ca mau eia.pdf (PDF) - AGA-Portal · contents pages 1. introduction 1 1.1 objective of the report 1 1.2 overview of ca mau power plant project 1 1.3 data and information sources 2

CONTENTS Pages 1. INTRODUCTION 1 1.1 OBJECTIVE OF THE REPORT 1 1.2 OVERVIEW OF CA MAU POWER PLANT PROJECT 1 1.3 DATA AND INFORMATION SOURCES 2 1.4 METHODS AND PROCESSES IN THE PREPARATION OF EIA REPORT 3 1.5 VIETNAMESE REGULATIONS, GUIDELINES AND ENVIRONMENTAL

STANDARDS APPLIED FOR THE PROJECT 4

1.5.1 Regulations and guidelines 4 1.5.2 Environmental standards applied for Ca Mau 2 power plant 4 1.5.3 Vietnamese standards applied for leaking, burning and exploding accidents 8

2. PROJECT DESCRIPTION 9 2.1 PLANT LAYOUT 9 2.2 THE POWER PLANT 9

2.2.1 Overview 9 2.2.2 Power Generation Process 9 2.2.3 Plant Auxiliary System 14

2.2.3.1 Share facilities for CM1 and CM2 Power plant 14 2.2.3.2 Cooling water System 14 2.2.3.3 Gas supply system for power plant 17 2.2.3.4 Fuel Diesel Oil System 19 2.2.3.5 Potable Water System 20 2.2.3.6 Demineralized Water Supply System 21 2.2.3.7 Wastewater Treatment System 21 2.2.3.8 Electricity System 21 2.2.3.9 List of used Chemicals in power plant 22 2.2.3.10 Fire and Explosion Fighting System 23 2.2.3.11 Communication System 24

2.3 CONSTRUCTION PHASE 24 2.3.1 Site Preparatory Works 24 2.3.2 Plant Construction 24

2.3.2.1 Main Plant 24 2.3.2.2 Wastewater Treatment System 25 2.3.2.3 Cooling Water System 25 2.3.2.4 Switchyard 26 2.3.2.5 Road system 26

2.4 PROJECT DISCHARGE SOURCES 26 2.4.1 Emissions 26 2.4.2 Effluents 26 2.4.3 Solid wastes 26

2.5 INVESTMENT FOR ENVIRONMENTAL PROTECTION 27 2.6 PROJECT SCHEDULE 28 3. EXISTING ENVIRONMENT OF THE PROJECT AREA AND ITS VICINITY 29 3.1 SCOPE OF PROJECT AREA 29 3.2 PHYSICAL ENVIRONMENT CHARACTERISTICS 29

3.2.1 Climate characteristic 29 3.2.2 Air quality in the project area 33 3.2.3 Hydrology Regime and Surface Water Quality 35

3.2.3.1 Hydrology regime at Cai Tau Confluence Area 35 3.2.3.2 Water quality 38

3.2.4 Sediment quality 40 3.2.5 Hydrogeology and groundwater quality 41

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3.2.6 Characteristics of Topography and Geology 42 3.2.7 Seismic, earthquake and erosion situation 44

3.3 BIOLOGICAL CHARACTERISTICS 44 3.3.1 Terrestrial ecosystem 44 3.3.2 Aquatic ecosystem 46 3.3.3 Natural Ecological Conservations at the project area and the vicinity 48

3.4 SOCIO-ECONOMIC CONDITION 48 3.4.1 Population 48 3.4.2 Administrative boundary and future planning orientation 49 3.4.3 Agricultural activities 49 3.4.4 Industrial production activities 50 3.4.5 Infrastructure and transportation 50

3.4.5.1 Infrastructure 50 3.4.5.2 Transportation 51

3.4.6 Aquaculture 52 3.4.7 Health and Education 52 3.4.8 Cultural relics, archaeology and tourism 52 3.4.9 Existing pollution sources before having project 53

4. POTENTIAL ENVIRONMENTAL IMPACT ASSESSMENT 55 4.1 CONSTRUCTION, INSTALLATION AND COMMISSION PHASES 55

4.1.1 Main sources of environmental impacts 55 4.1.2 Impact on physical environment 56

4.1.2.1 Air quality 56 4.1.2.2 Noise and vibration 58 4.1.2.3 Impacts on water quality 58 4.1.2.4 Impacts on soil quality 59

4.1.3 Impacts on biological environment 60 4.1.4 Interactions 60

4.2 OPERATION PHASE 61 4.2.1 Main source of environmental impacts 61 4.2.2 Impacts on physical environment 61

4.2.2.1 Air quality 61 4.2.2.2 Impact on water quality 67 4.2.2.3 Impacts on soil quality 82

4.2.3 Impacts on Biological environment 83 4.3 DECOMMISSION PHASE 83

4.3.1 Impact on physical environment 84 4.3.2 Impact on the biological environment 85

4.4 IMPACT ON THE SOCIO-ECONOMIC ENVIRONMENT 85 4.4.1 Impact on popualation and labour force distributtion 85 4.4.2 Impact on Agricultural development 86 4.4.3 Impact on industrial development 86 4.4.4 Impacts on transportation and infrastructure 86 4.4.5 Impact on aquaculture and fishery 87 4.4.6 Impact on public health 88 4.4.7 Impact on culture and landscape 88 4.4.8 Impact on economy 88

5. PRELIMINARY ENVIRONMENTAL RISK ASSESSMENT 89 5.1 SOME HAZARDOUS PROPERTIES OF FUELS USED IN THE PLANT 89 5.2 RESOURCE SENSITIVITY ASSESSMENT 91

5.2.1 Identify affected area 91 5.2.2 Sensitivity assessment of affected areas 92

5.3 DAMAGE ASSESSMENT OF ACCIDENTS 92 5.3.1 Gas leakage in the plant 92

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5.3.1.1 Possibility of gas leakage 92 5.3.1.2 Environmental damages 93

5.3.2 Fire/ explosion accident 94 5.3.2.1 Risk of fire/ explosion accident 94 5.3.2.2 Environmental damage 95

5.3.3. Oil and chemical spills 97 5.3.3.1 Chemical spills 97 5.3.3.2 Oil spills 98

6. MITIGATING MEASURES FOR ENVIRONMENTAL IMPACTS 99 6.1 MITIGATING MEASURES DURING CONSTRUCTING INSTALLING,

COMMISSIONING PHASES 99

6.1.1 Soil quality 99 6.1.2 Air quality 100 6.1.3 Water quality 100 6.1.4 Minimize negative impacts to Economic – Social 101

6.2 MITIGATION MEASURES FOR THE OPERATION PHASE 102 6.2.1 Air pollution treatment 102 6.2.2 Noise 103 6.2.3 Waste water treatment and discharge 103 6.2.4 Collection and treatment system for solid waste 105 6.2.5 Prevent incidents 106

6.3 DECOMMISSIONING PHASE 107 7. ENVIRONMENTAL MANAGEMENT PLAN 109 7.1 ENVIRONMENTAL MANAGEMENT PLAN FOR THE PROJECT 109

7.1.1 Environment Management Program 110 7.1.2 Checking and auditing environment management system 110

7.2 ENVIRONMENTAL MEASURING AND MONITORING PROGRAM 110 7.2.1 Monitoring Program for the Discharge Sources 111 7.2.2 Environment monitoring program in the vicinity 112

7.3 ENVIRONMENTAL MANAGEMENT TRAINING PROGRAM 115 7.4 EMERGENCY RESPONSE PLAN 115 8. CONCLUSIONS 117

LIST OF TABLES

Table 1.1 MAXIMUM ALLOWANCE LIMIT OF NOx, SO2 AND DUST IN AIR EMISSION OF THE THERMAL-POWER PLANT (TCVN 7440:2005) WITH CAPACITY > 600 MW, CONSTANT Kp = 0.7 FOR COMBINED CYCLE AND Kv = 1.2 FOR RURAL AREAS

Table 1.2 MAXIMUM LIMITS OF BASIC PARAMETERS IN THE AMBIENT AIR QUALITY (TCVN 5937:1995)

Table 1.3 MAXIMUM NOISE LIMIT IN PUBLIC AND RESIDENTIAL AREAS TCVN 5949:1995 (dB)

Table 1.4 ALLOWABLE VIBRATION LIMITS IN CONSTRUCTIVE AND INDUSTRIAL PRODUCTION TCVN 6962:2001 FOR SURROUNDING ENVIRONMENT

Table 1.5 THE LIMIT VALUE OF POLLUTANT PARAMETERS AND THEIR CONTENTS IN INDUSTRIAL WASTEWATER WHEN DISCHARGING INTO THE AQUATIC PROTECTION AREA - TCVN 6984-2001

Table 1.6 SUMMARY OF VIETNAMESE STANDARDS APPLIED FOR CA MAU 2 POWER PLANT Table 2.1 EMISSION DATA OF HEAT RECOVERY STEAM GENERATOR Table 2.2 DESIGN PARAMETERS OF ADDITIONAL COOLING WATER SYSTEM Table 2.3 ESTIMATION OF GAS DEMAND OF THE PLANT Table 2.4 INPUT GAS CHARACTERISTICS OF THE POWER PLANT Table 2.5 CHARACTERISTICS OF DIESEL OIL (DO) USED FOR CA MAU 2 POWER PLANT Table 2.6 ESTIMATED DIESEL OIL DEMAND OF THE PLANT Table 2.7 POTABLE WATER DEMAND OF CA MAU 2 POWER PLANT

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Table 2.8 LISTS OF USED CHEMICALS OF THE POWER PLANT Table 2.9 ENVIRONMENTAL PROTECTION FACILITIES OF CA MAU 2 POWER PLANT Table 2.10 SCHEDULE OF CA MAU 1 & 2 POWER PLANTS Table 3.1 STATISTICAL MONTHLY AVERAGE METEOROLOGICAL DATA AT CA MAU STATION

(1980 - 2004) Table 3.2 COMPARISON BETWEEN THE AVERAGE EVAPORATION AND RAINFALL IN THE

DRY SEASON (1980-2004) Table 3.3 ANNUAL AND SEASONAL RAINFALL IN CA MAU Table 3.4 THE MAXIMUM MONTHLY RAINFALL (MM) IN CA MAU IN COMPARISON WITH THE

STATISTICAL MEAN VALUES (1960-2004) Table 3.5 THE AVERAGE RAINFALL (MM) IN CA MAU STATION Table 3.6 ANALYTICAL RESULTS OF AIR QUALITY (day average) AT PROJECT AREA AND CAI

TAU RESIDENTIAL AREA IN 2005 Table 3.7 PARAMETERS OF NOISE AND VIBRATION Table 3.8 SUMMARY OF CURRENT CHARACTERISTIC AT TAC THU STATION Table 3.9 HYDROLOGICAL CHARACTERISTICS IN THE CA MAU GAS-POWER-FERTILIZER

COMPLEX IN BOTH DRY AND RAINY SEASONS, 2002 Table 3.10 PHYSIO-CHEMICAL PARAMETERS OF SURFACE WATER AT CA MAU POWER

PLANT IN 2005 Table 3.11 ANALYSED RESULTS OF CHEMICAL PARAMETERS OF SURFACE WATER Table 3.12 HEAVY METAL CONTENT IN SURFACE WATER (mg/l) Table 3.13 HEAVY METAL CONTENTS IN SEDIMENT Table 3.14 ANALYTICAL RESULTS OF GROUNDWATER QUALITY AT THE PROJECT AREA Table 3.15 RESULT OF HEAVY METAL CONTENTS IN GROUNDWATER AT THE PROJECT AREA Table 3.16 ANALYTICAL RESULT OF METAL CONTENT IN SOIL SAMPLES (µg/g) Table 3.17 THE ANALYTICAL RESULTS OF PHYTOPLANKTON AT THE PROJECT AREA Table 3.18 THE ANALYTICAL RESULTS OF ZOOPLANKTON AT THE PROJECT AREA Table 3.19 ANALYTICAL RESULTS OF BENTHOS AT THE PROJECT AREA Table 3.20 POPULATION AND LABOUR DISTRIBUTION AT HAMLETS 1, 3 AND 6 Table 3.21 THE DAILY NUMBER OF PASSENGER BOATS IN CAI TAU CONFLUENCE – KHANH

AN VILLAGE COMMUNE Table 3.22 AREA AND YIELD OF FISHERY AQUACULTURE IN U MINH DISTRICT Table 3.23 FIRE FOREST ACCIDENTS AT THE BEGINNING OF 2005 Table 4.1 MAIN SOURCES OF ENVIRONMENTAL IMPACTS DURING CONSTRUCTION/

INSTALLATION AND COMMISSIONING PHASES Table 4.2 ESTIMATION EMISSION VOLUME FROM OPERATION OF CONSTRUCTION

EQUIPMENT IN CONSTRUCTION AND INSTALLATION PHASE Table 4.3 COMPONENTS AND EMISSION VOLUME IN TESTING PROCESS FOR CA MAU 2

POWER PLANT Table 4.4 LOADS AND CONTENT OF REGULAR EMISSION GASES THROUGH THE STACK OF

CA MAU 2 POWER PLANT Table 4.5 THE HEIGHT AND DISTANCE OF AMBIENT BUILDINGS TO THE MAIN STACK OF CA

MAU 2 POWER PLANTTable 4.6 MAXIMUM AVERAGE GROUND CONCENTRATION OF POLLUTANTS WHEN

RUNNING FOR CA MAU 2 POWER PLANT FOLLOW OPTION 1&2 – WITH OBSTACLETable 4.7 MAXIMUM AVERAGE GROUND CONCENTRATION OF POLLUTANTS WHEN

RUNNING FOR THE BOTH PLANT 1&2 FOLLOWING OPTION 3&4 – WITH OBSTACLE Table 4.8 OPTIONS FOR COOLING WATER INTAKE AND DISCHARGE FOR CM1 AND CM2

POWER PLANTS Table 4.9 AVERAGE FLOW OF CAI TAU – ONG DOC RIVER (m3/s) IN THE DRY SEASON WHEN

THE POWER PLANTS COME INTO OPERATION (In case of opening Tac Thu sluice ) Table 4.10 AVERAGE FLOW RATE OF CAI TAU – ONG DOC RIVER (m3/s) IN THE DRY SEASON

WHEN POWER PLANT COMES INTO OPERATION (In case of Tac Thu sluice is closed) Table 4.11 AVERAGE AND MAXIMUM TEMPERATURE INCREASE ALONG CAI TAU – ONG DOC

RIVER BY 2 DISCHARGED OPTIONS IN 6 MONTHS OF DRY SEASON- DISCHARGED TEMPERATURE OF 35oC

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Table 4.12 AVERAGE AND MAXIMUM TEMPERATURE INCREASES ALONG CAI TAU-ONG DOC RIVER - DISCHARGED TEMPERATURE OF 40oC

Table INDUSTRIAL WASTEWATER TYPES OF THE CM2 POWER PLANT4.13 Table 4.14 THE AVERAGE BOD (mg/l) ALONG CAI TAU – ONG DOC RIVER WHEN BOTH POWER

PLANTS DISCHARGE INTO CAI TAU RIVER Table 5.1 LIMITS OF FLAMMABLE MIXTURE FORMING OF SOME ALKANES Table 5.2 CO2 CONTENT IN THE AIR AND CORRELATIVE CONSEQUENCES Table 5.3 POSSIBILITY OF GAS LEAKAGE IN THE CA MAU 2 POWER PLANT Table 5.4 GAS DISPERSION RESULT BY SAFETI MODEL Table 5.5 SUMMARY OF FIRE AND EXPLOSION ACCIDENTS IN THE POWER PLANT Table 5.6 EFFECTS FROM THERMAL RADIATION Table 5.7 OVERPRESSURE EFFECTS Table 5.8 AFFECTED SCALE OF FIRE/ EXPLOSION BY SAFETI MODEL Table 5.9

POTENTIAL OIL SPILLS IN THE POWER PLANT AND THE DO IMPORTING JETTY AREA

Table 7.1 REGULAR MONITORED PARAMETERS IN CA MAU 2 POWER PLANT Table 7.2 ENVIRONMENTAL SAMPLING LOCATIONS AT CA MAU POWER PLANT (In December,

2005) Table 7.3 PERIOD MONITORING PARAMETERS AND LOCATIONS AT SURROUNDING AREA OF

POWER PLANT Table 7.4 MONITORING FREQUENCY OF SURROUNDING ENVIRONMENT OF THE POWER

PLANT

LIST OF FIGURES Figure 2.1 DIAGRAM LAYOUT OF CA MAU 2 POWER PLANT Figure 2.2 MODEL OF COMBINED CYCLE POWER PLANT Figure 2.3 POWER GENERATION PROCESS DIAGRAM OF THE PLANT Figure 2.4 DIAGRAM OF COOLING WATER SYSTEM OF CA MAU 2 POWER PLANT Figure 2.5 SYSTEM TO PROVIDE FUEL GAS Figure 2.6 LAYOUT DISTRIBUTION OF CA MAU 2 POWER PLANT Figure 3.1 WIND ROSE AT CA MAU STATION Figure 3.2 LOCATION OF ENVIRONMENTAL SAMPLING STATIONS IN CA MAU POWER PLANT Figure 3.3 LOCATION OF HYDROLOGY MEASURING STATIONS IN PROJECT AREA Figure 3.3a MAP OF MAXIMUM FLOODING IN 2000

Figure 3.4 GENERAL PLANNED LAYOUT OF RESETTLEMENT AREA SERVING FOR INDUSTRIAL ZONES AND CENTER OF KHANH AN TOWN IN FUTURE

Figure 3.5 THE MAIN WATERWAY ROUTES TO PROJECT AREA

Figure 4.1 DIAGRAME OF COOLING WATER INTAKE SITE, DISCHARGE SITES IN OPTIONS AND TRANSECT SITES DESCRIBING MODELING RESULTS

Figure 4.2 AVERAGE FLOW ALONG CAI TAU – ONG DOC RIVER IN CASE OF WITHOUT AND WITH TWO POWER PLANTS – AS OPENING TAC THU SLUICE

Figure 4.3 AVERAGE FLOW RATE ALONG CAI TAU – ONG DOC RIVER WITHOUT AND WITH TWO POWER PLANTS (Case of Tac Thu closing)

Figure 4.4 HIGHEST TEMPERATURE INCREASE BY TWO DISCHARGE OPTIONS DURING 6 DRY MONTHS (DISCHARGED TEMPERATURE OF 35OC)

Figure 4.5 AVERAGE TEMPERATURE INCREASE BY TWO DISCHARGE OPTIONS DURING 6 DRY MONTHS (DISCHARGED TEMPERATURE OF 35OC)

Figure AVERAGE TEMPERATURE INCREASES ALONG THE RIVER BY TWO DISCHARGED OPTIONS IN SIX DRY MONTHS – DISCHARGED TEMPERATURE OF 40oC4.6

Figure 4. 7 MAXIMUM TEMPERATURE INCREASES ALONG RIVER BY TWO DISCHARGED OPTIONS IN SIX DRY MONTHS – DISCHARGED TEMPERATURE OF 40oC

Figure 6.1 WASTEWATER TREATMENT FLOWCHART OF CA MAU 2 POWER PLANTFigure 7.1 SAMPLING SITES OF WATER ENVIRONMENT MONITORING FOR CA MAU 1 AND CA

MAU 2 POWER PLANTS

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ABBREVIATION ANSI : American national standards institute BLEVE : Boiling liquid expanding vapor explosion BOD : Biological oxygen demand CCP : Cycle power plant CM1 : Ca Mau 1 CM2 : Ca Mau 2 CPMB : Ca Mau Gas – Power – Fertilizer Project Management Board CW : Cooling Water DC : Drill Collar DEIA : Detail Environmental Impact Assessment DO : Diesel Oil DTS : Total oil content EIA : Environmental Impact Assessment EPC : Engineering Procurement Construction E-SE : East-South East EVN : Electricity Vietnam FEED : Front End Engine Design GT : Gas turbine HP : High pressure HRSG : Heat recovery steam generators HSE : Health, Safety and Environment IGPF : Integrated Gas – Power – Fertilizer IP : Intermediate pressure ISC-ST3 : The Industrial Source Complex Short-Term LFL : Low flammable limit LP : Low pressure LPG : Liquid Petroleum Gas MONRE: : Ministry of Natural Resource and Environment MoSTE : Ministry of Science, Technology and Environment NFPA : National Fire Prevention Association ODA : Organization Development Assistance OREDA : Offshore Reliability Data PP : Power plant RDCPSE : Research and Development Center for Petroleum Safety and Environment RO : Reverse Osmosis SE : South East S-SE : South-South East ST : Steam turbine TCVN : Vietnamese standards THC: : Total hydrocarbon content ULF : Upper flammable limit UPS : Uninterruptible Power Supply USEPA : United State of Environmental Protection Agency UVCE: : Unconfined vapor cloud explosion VCE : Vapor cloud explosion VND : Vietnamese Dong VOC : Volatile Organic Compound WHO : World Health Organisation W-SW : West-South West WTS : Wastewater treatment system

REFERENCES

[1] PETROVIETNAM - NĐ-2005-07 PROJECT, DECEMBER, 2005 Investment Project of Ca Mau 2 Combined Cycle Power Plant - Volume 1: General explanation.

[2] SOUTHERN HYDRO METEOROLOGICAL CENTER, 2005. Hydro Meteorological Report of Ca Mau, during 1980 – 2004.

[3] DEPARTMENT OF NATURAL RESOURCE AND ENVIRONMENT OF CA MAU,

2005 Existing Environmental Report of Ca Mau province, 2005

[4] RESEARCH & DEVELOPMENT CENTER FOR PETROLEUM SAFETY AND

ENVIRONMENT (RDCPSE), DECEMBER, 2005. Supplemental Environmental Baseline Study Report for Ca Mau Power Plant

[5] RESEARCH & DEVELOPMENT CENTER FOR PETROLEUM SAFETY AND ENVIRONMENT (RDCPSE), JANUARY, 2004. Detail EIA Report for Ca Mau Power Plant Project

[6] LUU VAN THUAN-2005 Hydrology Report of Cai Tau, Trem and Ong Doc Rivers.

[7] PEOPLE'S COMMITTEE OF CA MAU PROVINCE, JULY, 2002

Existing Environmental Assessment Survey for predicting potential reserve, quality and production planning of underground water in Ca Mau province.

[8] INFORMATIC REMOTE SENSING DEPARTMENT - HO CHI MINH PHYSICAL SUBINSTITUTE, DECEMBER, 2002. Study on Shoreline Erosion and Variation for the Southwest Coastal Area from Ca Mau cape to Cambodian border using Satellite images

[9] DEPARTMENT OF SCIENCE, TECHNOLOGY AND ENVIRONMENT OF CA MAU PROVINCE Report on Existing Erosion along rivers in Ca Mau province.

[10] GOVERNMENTAL SCIENTIFIC COMMITTEE General Basic Surveying Program for the Mekong Delta 60-02

[11] PEOPLE COMMITTEE OF KHANH AN COMMUNE, 2005

Statistic data of social - economic situation of Khanh An Commune [12] CONSTRUCTIONAL CONSULTING COMPANY, MINISTRY OF CONSTRUCTION,

2000 Existing and protection and development Planning for Coastal Mangrove Forest in the Mekong Delta

[13] MANAGEMENT BOARD OF WHARF A, WARD 1, CA MAU CITY, 2002

Number of Daily boats/barges back and forth within six initial months of 2002

[14] NGO CHI HUNG, DEPARTMENT OF SCIENCE, TECHNOLOGY AND ENVIRONMENT OF CA MAU PROVINCE, 2002 EIA Report for forest fire and its impacts on social- economic condition

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[15] WORLD HEALTH ORGANIZATION, GENEVA, 1993 Assessment of sources of Air, Water, and Land Pollution – A Guide to Rapid Source Inventory Techniques and Their Use in Formulating Environmental Control Strategies Part one: Rapid Inventory techniques in Environmental Pollution by Alexander P. Economopoulos – Democritor University of Thrace

[16] PROF. Ph.D PHAM NGOC ĐANG, HA NOI SCIENTIFIC AND

TECHNOLOGICAL PUBLISHER, 1992. Air Pollution in Urban and Industrial Area.

[17] ASSOC. PROF. Ph.D. HOANG VAN BINH (NOVEMBER, 1996),

HO CHI MINH CITY INSTITUTE OF HYGENE AND PUBLIC HEALTH Professional Document - Industrial Toxicity and Prevention of infecting poisons in producing process (Volume 1),

[18] RDCPSE & DNV TECHNICA, APRIL, 2002

Quantitative Risk Assessment for Dinh Co - Thi Vai pipeline [19] AKIRA WADA ET ALL. JAPAN - AUGUST, 1975

Study on adaptability of prediction method of simulation analysis for diffusion of discharged warm water in the sea

[20] ENVIRONMENTAL BUREAU - MINISTRY OF SCIENCE, TECHNOLOGY

AND ENVIRONMENT, 1999 Guidelines for preparation and appraisal of Environmental Impact Assessment Reports of thermal power plant project.

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Revised report on DEIA for Ca Mau Power Plant Project (Part of DEIA for Ca Mau 2 Power Plant) 1

CPMB– RDCPSE-Final report June, 2006

Section 1.

INTRODUCTION

1.1 OBJECTIVE OF THE REPORT Ca Mau Power Plant sited into Ca Mau – Gas – Power – Fertilizer Project was approved to build at Khanh An commune, U Minh district, Ca Mau province by the Government in October, 2001. The project is invested by Petrovietnam and is directly managed by Ca Mau Gas – Power – Fertilizer Project Management Board (CPMB). According to the conclusion of the Head of State Guidance for the key Petroleum projects, Vice Prime Minister Nguyen Tan Dung, in the conference dated 1st September 2005, noticed that Ca Mau 2 power plant will be built to satisfy the deficient power of the country and effectively utilizes the natural gas resource at the Southwest continential shelf. This environmental impact assessment (EIA) report is complied according to the requirements of Petrovietnam and Ministry of Natural Resource and Environment (MONRE). Objectives of this report include:

− To update the existing environmental conditions at the project area for revised Ca Mau power plant project and its vicinity;

− To assess supplementary potential environmental impacts caused by Ca Mau 2 power plant implementation and propose mitigation measures to minimise the negative environemntal impacts and satisfy the Vietnamese law requirements;

− To provide the scientific basis for the Ministry of Natural Resource and Environment and Department of Natural Resource and Environment of Ca Mau to assess the compliance of the project owner 's requirement proposed in the EIA report.

1.2 OVERVIEW OF CA MAU POWER PLANT PROJECT The revised Ca Mau power plant project includes two (02) plants: Ca Mau 1 power plant and Ca Mau 2 power plant. The development process of two plants is summarized as follows:

Ca Mau 1 power plant approved in October 2001 is located in the Gas – Power – Fertilizer complex at hamlet 1, Khanh An commune, U Minh district, Ca Mau province. This is a Combined Cycle Gas Turbine Power Plant with design capacity of 750 MW which can use both natural gas or DO fuel. According to the technical design approved by the Minister of Industry No 299/QĐ-NLDK on 25th February 2004, the plant’s configuration is multi–structure one including two gas turbine generators, two heat recovery steam generators (HRSG), 1 condensing steam turbines generator and accompanied power generators. The detailed environmental impact assessment report of Ca Mau 1 power plant was carried out in 2003 and approved on 23rd April 2004 by Decision No 460/QĐ-BTNMT of the Ministry of Natural Resource and Environment (Appendix 1).



To overcome the electricity deficiency in the dry season of 2007-2008, the Government requests that Ca Mau 1 power plant will be run with two stages: i) put the Single Cycle Power plant to generate power in March 2007 and ii) then, complete and change into the Combined Cycle Power plant at the designed capacity 750MW. After calculation in detail design, emission gas content at the discharge sources is different with the mentioned emission gas in the approved detail EIA report for Ca Mau 1 power plant. However, when comparing with the current Vietnamese standards, the emission gas content at the top of stack is still lower than TCVN 7440-2005. So, the plant's main stack height is considered to reduce to 40m and the bypass-stack height is considered to reduce to 30m and it still satisfies Vietnamese standards for emission gas.

About wastewater of Ca Mau 1 power plant, according to the approved design, the cooling water of Ca Mau 1 power plant will be discharged into Cai Tau river, and the industrial effluents discharged from plant will be treated by the plant's treatment system, then routed to biological test pond together with the treated wastewater of Ca Mau fertilizer plant and finally discharged into Ong Doc river. But now, the fertilizer plant has not yet built and the biological pond is proposed to build in complex constructions of the fertilizer plant. So, the discharge site of treated industrial wastewater of Ca Mau 1 power plant is changed to discharge into Cai Tau river. The supplemented EIA for the above-mentioned changes was conducted in November 2005 and approved by the Ministry of Natural Resource and Environment according to Decision No 297/QĐ-BTNMTR of March 23, 2006 (Appendix 1). Ca Mau 2 power plant project is approved by the Petrovietnam Management Board according to the Decision No 1459/QĐ-HĐQT of February 15, 2006 for revised Ca Mau power plant project. Ca Mau 2 power plant has designed capacity of 750 MW and similar configuration to Ca Mau 1 power plant. It is planned to be built on the area of Ca Mau fertilizer plant in Ca Mau gas-power-fertilizer complex. The main fuel for Ca Mau 2 power plant 's operation is natural gas from PM3 - CAA block and Cai Nuoc block provided by gas distribution station sited in the gas-power-fertilizer complex. Ca Mau 2 power plant will also be built at the same time with the Ca Mau 1 power plant which is planned to complete in 2008. The detail description of Ca Mau 2 power plant will be presented in chapter 2 of this report.

The name of this report is taken according to the approved project name by the Government: “Revised Ca Mau Power Plant Project”. Part of EIA is newly made for Ca Mau 2 Power Plant. Therefore, this report is named “Revised report on DEIA for Ca Mau Power Plant Project (Part of DEIA for Ca Mau 2 Power Plant)”.

1.3 DATA AND INFORMATION SOURCES The technical data used in this report is supplied mainly by Ca Mau CPMB and the design consultant. The environmental data is carried out, measured, analysed and assessed by RDCPSE. Specially, the economic and social data is collected from the local authorities and related departments. Detail main used document are summarized as follows:

The general design document of Ca Mau 1 power plant project is provided by Ca Mau CPMB in November, 2005.

General explanation for investment project of Ca Mau 2 power plant - volume 1, December, 2005 together with technical drawings is

provided by Ca Mau CPMB.

Supplementary meteorological data in 2003 - 2004 is provided by Southern Meteorological Station.



The data of supplementary baseline environmental survey at the Ca Mau power plant area was conducted by RDCPSE in the sampling, measuring, vegetation field survey and meeting with local authorities from 19 –24th December, 2005.

The revised environmental protection law and the current environmental standards .

1.4 METHODS AND PROCESSES IN THE PREPARATION OF EIA REPORT

This detail EIA report is prepared in accordance with the Guidelines for preparation of the EIA report for investment projects (Circular No. 490/1998/TT-MoSTE) issued by MoSTE in 1998.

The main methods used in the preparation of this EIA report are as follows:

1. Statistical method: is used to treat the environmental analytical data, and the meteo-hydrological and socio-economic data;

2. Modeling method: is used to calculate and stimulate the air emission processes, the wastewater and the thermal dispersion caused by project activities. Some mathematic models are used for preparing this report including:

Air dispersion modeling ISCST3 - version 3.2 is used to assess the level of air dispersion in operational process of Ca Mau power plant. This model is established and developed by United State of Environmental Protection Agency (USEPA) and is accredited by international organizations to use as a calculating and forecasting tool of impacts to air quality by industrial air emission;

Hydraulic modeling SAL: is used to calculate the variation of hydraulic regime due to the cooling water intake activities of the project. This model was established by Assoc.Prof.Dr. Nguyen Tat Dac and is applied in calculating the hydraulic regime and the drainage ability of the whole Mekong Delta.

Wastewater dispersion modeling is used to calculate and to stimulate the organic wastewater dispersion and thermal dispersion process on the river/ canal system affected by the tides under different uses.

3. Field survey and measurement method: is used to take samples, field measure and analyse in the laboratories (air, water, soil, sediment and biology samples) at the project area. Moreover, this method is used to survey the vegetation cover, take the photographs and interview in the field trips for collecting the existing environment and socio-economic situation;

4. Social investigation method: is used to interview the authorities, departments and local residents at the project area.

5. Comparative method: is used to evaluate environmental quality of air, soil, water, sediment and biology in comparison with existing current Vietnamese and International environmental standards;

During prepation process this report, the project owner has co-operated closely with RDCPSE and the design consultant (Power Engineering Consulting Company No.2 and Electrowatt-Econo Consultant Company), general LILAMA contractor and Petrovietnam Health, Safety and Environment Division in order to ensure the accuracy and consistency from the used information. Furthermore, the project owner has co-operated closely with the local authorities, especially Department of Natural Resource and Environmet, Fishery Department, Agricultural and Rural Development Department and Construction Department in assessing and secllecting of wastewater discharge sites of the revised power plant project.



1.5 VIETNAMESE REGULATIONS, GUIDELINES AND

ENVIRONMENTAL STANDARDS APPLIED FOR THE PROJECT 1.5.1 Regulations and guidelines The current laws, regulations and guidelines are used to refer in the report including:

Revised Law on Environmental Protection, 2006.

Government Decree No.175-CP dated on October 18,1994 providing guidane for implement of the Law on Environmental Protection;

Government Decree No.143/2004/NĐ-CP dated July 12, 2004 revising and supplementing article 14 of Decree No.175-CP dated on October 18,1994 providing guidane for implement of the Law on Environmental Protection;

Approved Decision of Feasibilities Study report No.1333/QD-TTg dated October 8th, 2001 issued by Prime Minister;

Approved Decision of Bidding plan No.444/QD-TTg dated June 6th, 2002 issued by Prime Minister;

Approved Decision of Front End Engine Design (FEED) No.299/QĐ-NLDK dated February 25th, 2004 issued by Minister of Industrial Ministry;

Governmental Decree No.121/2004/NĐ-CP dated May 12th, 2004 providing the administrative purnishment, and environmental prtection.

Approved Decision No.1195/QĐ-TTg dated November 11, 2005 on providing instructive, specific policies for constructive investment of urgent power projects during 2006-2010.

Governmental Decision No.155/1999/QD-TTg dated July 16th, 1999 providing the regulations on hazadous waste management;

Circular No.490/1998/TT-KHCN&MT dated January 29th, 1998 issued by Ministry of Science, Technology and Environment on guidelines for preparartion and appraisal of Environmental Impact Assessment Reports of Investment Project;

Circular No.2262 market-Mtg of December 26th, 1995 issued by Ministry of Science, Technology and Environment on guiding of oil spills recovery;

Petroleum law dated July 6th, 1993 and Governmental Decree 84/CP dated December 17th, 1996 regulating details of the implementation of the petroleum law;

Governmental Decision No.41/1999/QD-TTG dated March 8th, 1999 providing the regulations of safety management for the petroleum activities;

Decision No.395/1998/QD-KHCN&MT of April 10th, 1998 issued by MoSTE about Regulations for Environmental Protection in searching, exploring, developing mines and exploiting, storing, transporting, processing oil and related services;

Vietnamese standards issued by Ministry of Science, Technology and Environment in 1995, 2001 and 2005.

1.5.2 Environmental standards applied for Ca Mau 2 power plant 1. Vietnamese standards about air emission limits In 2005, Ministry of Science, Technology and Environment issued "Air emission standards for thermo-power industry plant TCVN 7440:2005" providing the allowance maximum



This standard is applied to assess and appraise environmental requirements for the thermo-new power plants or operating thermo-power plants that is improved bigger and widen. The maximum allowance limit of pollutants (NOx, SO2 and dust) in air emission source of thermo-power plant is given in Table 1.1. Table 1.1 MAXIMUM ALLOWANCE LIMIT OF NOx, SO2 AND DUST IN AIR EMISSION OF

THE THERMAL-POWER PLANT (TCVN 7440:2005) WITH CAPACITY > 600 MW, CONSTANT Kp = 0.7 FOR COMBINED CYCLE AND Kv = 1.2 FOR RURAL AREAS

Unit: mg/Nm3

Used fuel Parameters

Coal Burning Oil Burning Gas Burning NOx (mg/Nm3) 840 (1000) 504 (600) 210 (250) SOx (mg/Nm3) 420 (500)

420 (500) 252 (300)

Dust (mg/Nm3) 168 (200) 126 (150) 42 (50) Notes: the value in the brackets () is the value in TCVN 7440:2005 which haven't revised by the project constant Kp & Kv. Owing to standard of TCVN 7440:2005 doesn't stipulate for CO content, so, the maximum allowance limit of CO in air emission will comply with the standard TCVN 6993:2001 with A technology (KCN = 0.6), constant Karea = 1.2 and discharge flow Q3 > 20,000 m3/h is 180 mg/Nm3. For the ambient air environment, Ca Mau 2 power plant will comply with the maximum allowance limits on ground according to TCVN 5937:1995 (Table 1.2).

Table 1.2 MAXIMUM LIMITS OF BASIC PARAMETERS

IN THE AMBIENT AIR QUALITY (TCVN 5937:1995)

Parameters Average of 1 hour Average of 8 hours Average of 24 hours CO (mg/m3) 40 10 5 NO2 (mg/m3) 0.4 - 0.1 SO2 (mg/m3) 0.5 - 0.3 Pb (mg/m3) - - 0.005 O3 (mg/m3) 0.2 - 0.06 Suspended dust (mg/m3)

0.3 - 0.2

Source: 31 compulsory Vietnamese Standards – Hanoi, 2002 Note: (-) : undefined

2. Vietnamese standards about noise and vibration − Noise limits for surrounding environment Noise caused by project implementation for commercial and service area and factories intermingling in residential area will be applied to TCVN 5949:1995 (Table 1.3).



Table 1.3 MAXIMUM NOISE LIMIT IN PUBLIC AND RESIDENTIAL AREAS TCVN 5949:1995 (dB)

Time No. Area From 6h to 18h

From18h to 22h

From 22h to 6h

1 Quiet areas: Hospital, library, sanatoria, kindergarten, schools

50 45 40

2 Residential, hotels, houses, administrative office 60 55 45 3 Commercial and service areas 70 70 50 4 Small industrial factories intermingling in residential

areas 75 70 50

Source: 31 compulsory Vietnamese Standards – Hanoi, 2002 − Vibration limits for surrounding environment Vibration caused by project constructive and industrial production activities for surrounding environment will be applied to TCVN 6962:2001 (Table1.4).

Table 1.4 ALLOWABLE VIBRATION LIMITS IN CONSTRUCTIVE AND INDUSTRIAL

PRODUCTION TCVN 6962:2001 FOR SURROUNDING ENVIRONMENT Vibration limits in

construction activity (dB)Vibration limits in

production activity (dB) No.

Area

7h-19h 19h-7h 6h-18h 18h-6h

1 Quiet areas 75 Basic level* 60 55

2 Residential, hotels, houses, administrative office

75 Basic level* 65 60

3 Small industrial factories intermingling in residential areas

75 Basic level* 70 65

Source: 31 compulsory Vietnamese Standards – Hanoi, 2002 Note * Basic level is vibration level measured when without facilities working in the assessed area 3. Vietnamese environmental standard of wastewater − Discharging cooling water: According to the design, Ca Mau 2 power plant will take cooling water from Cai Tau river through the cooling water canal that is used together with Ca Mau 1 power plant. In the operational phase, the cooling water system doesn't take part in the technological process, but is used for indirect thermal exchange. So, the cooling water can be considered as non-pollution discharged water, so it hasn't to comply the Vietnamese Environmental standards of wastewater. As for the temperature of cooling water, Ca Mau 2 power plant will strictly comply the Vietnamese standard TCVN 5945:1995 with cooling water temperature ≤ 40oC into the received environment that used for the purposes of water traffic, irrigation, swimming and fishery aquaculture.



− Discharging industrial wastewater Industrial wastewater considered as the discharge water from production process will be treated to meet the Vietnamese standard before discharging into environment. According to the discharged quantity and river flow, the limit value of pollutant parameters and content in the treated industrial wastewater of Ca Mau 2 power plant when discharging into the river will not be exceed the limit value in column B of TCVN 6984:2001 (Table 1.5) applied for the aquatic protection area.

Table 1.5 THE LIMIT VALUE OF POLLUTANT PARAMETERS AND THEIR CONTENTS IN INDUSTRIAL WASTEWATER WHEN DISCHARGING INTO THE AQUATIC

PROTECTION AREA - TCVN 6984-2001

Q>200 m3/s Q= 50 - 200 m3/s Q<50 m3/s No. Parameters

F1 F2 F3 F1 F2 F3 F1 F2 F3

1 Color, Co-Pt at pH=7 50 50 50 50 50 50 50 50 50

2 Smell, Sensibility light light light light light light light light light

3 TSS mg/l 100 100 100 90 80 80 80 80 80

4 PH 6-8.5 6-8.5 6-8.5 6-8.5 6-8.5 6-8.5 6-8.5 6-8.5 6-8.5

5 BOD5 (20oC) mg/l 50 45 40 40 35 30 30 20 20

6 COD (mg/l) 100 90 80 80 70 60 60 50 50

7 As (mg/l) 0.1 0.1 0.1 0.08 0.08 0.08 0.05 0.05 0.05

8 Cd (mg/l) 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01

9 Pb (mg/l) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5

10 Fe (mg/l) 5 5 5 4 4 4 3 3 3

11 CN- (mg/l) 0.1 0.1 0.1 0.05 0.05 0.05 0.05 0.05 0.05

12 Oil & Mineral petrol (mg/l) 10 5 5 10 5 5 5 5 5

13 Fat (mg/l) 20 20 20 20 10 10 10 10 10

14 Organic Phosphor (mg/l) l 1 1 0.8 0.8 0.5 0.5 0.5 0.5 0.5

15 Total Phosphor (mg/l) 10 8 8 6 6 6 5 5 5

16 Cl- (mg/l) 1000 1000 1000 800 800 800 750 750 750

17 Surfactant (mg/l) 10 10 10 5 5 5 5 5 5

18 Coliform MPN/100ml 5000 5000 5000 5000 5000 5000 5000 5000 5000

19 PCB (mg/l) 0.02 0.02 0.02 0.01 0.01 0.01 0.01 0.01 0.01

Source: 31 compulsory Vietnamese Standards – Hanoi, 2002 Notes: -Q: river flow, m3/s

− F: discharged capacity , m3/day (24 hours) − F1: from 50 m3/day to lower than 500m3/day − F2: from 500 m3/day to lower than 5000m3/day − F3: equal or over 5000m3/day

The project owner has responsibilities to control emission gas, liquid effluents, and solid wastes generated from the project operation as well as monitoring the ambient environment surrounding project area in accordance with the environmental criteria listed in above tables during the project operation life. In general, Vietnamese standards applied for Ca Mau 2 power plant are listed in Table 1.6.



Table1.6 SUMMARY OF VIETNAMESE STANDARDS APPLIED FOR CA MAU 2 POWER PLANT

No. Parameters Standards NOx, SOx and dust at discharge sources TCVN 7440:2005 1 CO at discharge sources TCVN 6993:2001

2 CO, NOx, Sox and dust in surrounding environment TCVN 5937:1995 3 Noise in surrounding environment TCVN 5949:1995 4 Vibration in surrounding environment TCVN 6962:2001 5 Temperature of cooling water TCVN 5945:1995 6 Industrial wastewater TCVN 6984:2001

1.5.3 Vietnamese standards applied for leaking, burning and exploding accidents The gas leakage and fire detection and protection system will be designed, installed and operated and met the Vietnam standards (TCVN). The Vietnamese Standards applied to fire and gas leakage are listed as follows:

− TCVN 3254-89: Fire protection, general safety and requirements;

− TCVN 35738-93: Fire detection and alarm system, technical requirements;

− TCVN 4090-85: Main oil and oil products pipelines – design principle.

− TCVN 5307-91: Oil and oil product storage tank;

− TCVN 5739-1993: Fire fighting equipment – coupling heads;

− TCVN 6379-1998: Fire fighting equipment. Fire fighting water pipe. Technical Requirements;

− TCVN 2622-1995: Fire Protection for Buildings. Design Requirements;

− TCVN 5760- 1993: Fire extinguishing systems. General Requirements for project design, installation and utilization. Vietnam Construction standards, volumes 1, 2 & 3. Particularly about fire fighting and preventing, the project owner had submited a separate report on project general design fire fighting and preventing plan to Agency on Fire Protection and Fire Fighting - Ministry of Security.

Revised report on DEIA for Ca Mau power plant project (Part of DEIA for Ca Mau 2 power plant) 9


Section 2. PROJECT DESCRIPTION

2.1 PLANT LAYOUT [1] The Ca Mau 2 Power Plant is located in the Integrated Gas – Power – Fertilizer (IGPF) in Khanh An commune, U Minh District, Ca Mau province, which is 9 kilometer far from Ca Mau City to the Northwest. The Ca Mau Power Plant 2 is a combined cycle power plant (CPP), which uses natural gas for input fuel and has a capacity of 750 MW. In combined cycle power plant, all major facilities are standardized and manufactured in separate modules in order to minimise the on-site construction and fabrication costs. Therefore, the arrangement of these facilities of the plant is also based on a number of standard designs and module configurations. The plant overall layout arrangement is designed in accordance with these following factors:

• Standardized technology of the CPP • Design, technique and safety criteria and standards • Geological and topographical characteristics • Tie-in with the power network • Internal traffic • Fire and Explosion Prevention • Good management of shared facilities in the IGPF • Good management of the working environment in the IGPF

The diagram of plant layout arrangement of Ca Mau 2 power plant is presented in Figure 2.1. 2.2 THE POWER PLANT 2.2.1 Overview The Ca Mau 2 power plant has a capacity of 750 MW with the total area of ~ 10 hectares. The main fuel for the plant is natural gas produced at Block PM3 in Southwest Vietnam Sea. The stand-by fuel (will be used if there is emergency in gas supply) is Diesel Oil (DO), which are stored in two (2 oil tanks with capacity of) 5,000m3/tank. 2.2.2 Power Generation Process



The CPP is a multi-saft configuration comprising of 2 gas turbines (GT) of F generation, 2 heat recovery steam generators (HRSG), 1 steam turbine (ST) and following generators.

Electric and Control Container

Generator Lead Generator

Input System

Diffuser

Gas Turbine

HRSG

Figure 2.2 MODEL OF COMBINED CYCLE POWER PLANT The principal power generation process of the CPP is summarised as follow (Figure 2.3): Natural gas from distribution centre is heated (or DO from storage tanks) and fed into the combustion chambers of 2 gas turbines. In these chambers, thermal energy resulted from gas firing is converted into electrical energy. Exhaust from 2 gas turbines is subsequently routed to 2 HRSG. High-pressure steam from HRSG is directed to steam turbine (ST) and generator to produce electricity.

Condensation

Fuel

ST x 1 260 MW x 1

Steam

HRSG

Exhaust from GT

GT x 2 250 MW x 2

Figure 2.3 POWER GENERATION PROCESS DIAGRAM OF THE PLANT



a) Gas Turbine – Generator Unit The CPP will utilize the gas turbines of F-Generation, model V94.3A, which is manufactured by Siemens (Germany). The gas turbine V94.3A has a nominal rating of 260 MW (ISO Standard). The following generator is 165-350 MVA, 50 Hz, and designed in compliance with ANSI and IEC standards. The operating principle of the GT unit is summarised below: Compressors via intake air filter feed air for combustion in. After compressed, air is supplied to the combustion chamber where the gas or oil fuel is burned. Heat generated from fuel combustion process is converted into force rotating gas turbine compressors and generators. Each gas turbine unit comprises of compressor, gas turbine, cooling system and auxiliaries.

• The compressor consists of 15 blade stages with a pressure ratio of 17, and provide compressed air for fuel combustion process and turbine cooling;

• The gas turbine has 4 stationaries and having blades made of high temperature alloy. Blades of the first three rows are specially coated for protection against high temperature corrosion. The combustion chamber is annular type and has 24 HR3 burners, which is capable to fire both gaseous and liquid fuels. The HR3 burner is also low-NOx generation and minimizes the CO emission on account of the pre-mix and the stable and ultra-high efficient firing process.

• The cooling system use compressed air to cool the rotor and blades, without the need for other external cooling. The cooling air for the turbine is extracted from appropriate compressor stages, as each blade row requires cooling air at different pressure;

• Auxiliary systems: control and measurement system (monitoring rotation speed, temperature,..), mechanical protection system (safety blow off, hydraulic valve), liquid fuel auxiliary system (diffuser, premix, purging water,...), lube oil system, air-filter house, silencer, fire fighting system (detector, alarm, fire fighting,...), and etc.

b) Heat Recovery Steam Generator The HRSG is the important faction of the power plant, which is responsible for transferring heat from gas cycle to steam cycle. In HRSG, heat of exhaust gas from gas turbine is recovered to produce superheated steam from feeding water. HRSGs of Ca Mau 2 power plant have a design of 3 pressure stages: the high (HP), the intermediate (IP) and the low (LP) pressures. Steams from them are supplied to the appropriate stages of the Steam Turbine (ST) to generate electricity.



High-pressure Heat Recovery System

Feed water from HP feed pump is conducted to the HP section of HRSG. Exhaust gas from GT is fed into the system beginning from the superheated. Superheated steam from the super heater is directed to the HP Turbine. Exhaust from HP economizer is then delivered to the inlet of IP super heater of the IP Heat Recovery system. Intermediate-pressure Heat Recovery System

Similar to the HP process, feed water is heated in the IP economizer and steam is generated in the IP evaporator. Subsequently, the saturated IP steam is routed via the IP super heater and mixed with the exhaust steam “cool reheated steam” of HP Turbine. The mixed steam is the entering the reheat section for being reheated up to saturated state. This mixed steam, called “hot reheated steam”, is then supplied to the IP Turbine. Low-pressure Heat Recovery System Feed water, extracted from intermediate stage of IP feed water pump, will be heated in the LP economizer before entering the LP drum. Similar to the HP and IP process, steam is generated in the LP evaporator and may be superheated in superheated LP set subjecting to the design requirements of ST manufacturer. LP superheated steam is supplied to the LP Turbine together with exhaust from IP Turbine.



Exhaust in each HRSG after passing through heat exchangers will be emitted to the atmosphere via separate stacks with minimum height of 40 meters. Data on emissions of each HRSG is presented in Table 2.1.

Table 2.1 EMISSION DATA OF HEAT RECOVERY STEAM GENERATOR

Description Unit Gas Firing DO Firing Number of Stack 1 Stack / 1 HRSG 1 Stack / 1 HRSG Stack diameter m 6.5 6.5 Stack height m 40 40 Exhaust velocity m/s 20 21 Exhaust flow m3/s 674 736 Temperature at stack outlet ºC 97 138 Emission rate (approximate): N2O2CO2 and SO2H2O NOxSOx

% % % %

mg/Nm3

mg/Nm3

72.86 11.57 4.015 10.86 51.3 0.83

69.86 10.21 5.717 13.37 149.8

180-277*

Source: General Report of investment project for Ca Mau 2 Power Plant- volume 1- December, 2005 Note: * according to the Sulfur content of 0.3-0.5% wt. c) Steam Turbine – Generator Unit The steam turbine has three stationaries: high pressure (HP), intermediate pressure (IP) and low pressure (LP). Auxiliary systems are: auxiliary steam system, lube oil system, hydraulic control system, and steam valves. The generator is designed following IEC and ANSI standards, rating of 165-350 MVA and frequency of 50Hz. HP steam from HRSG is supplied to the HP stationary of steam turbine via the main stop valve and control valve. From the outlet of HP Turbine, the cold reheated steam is mixed with IP steam and then being superheated in IP super heater. The hot reheated steam is entering the IP Turbine via a stop valve and control valve. In LP Turbine, LP steam from LP section of HRSG is fed through a stop valve and control valve. The steam will depressurize among blade rows and rotate the generator. After the turbine, the steam is routed to the condenser surface-cooled by water. Separate HP, IP and LP steam by-pass stations will be equipped to accomplish high operational flexibility in start-up, halt and other abnormal operation. The by-pass system is designed with 100% of maximum steam capacity.



2.2.3 Plant Auxiliary System 2.2.3.1 Share facilities for CM1 and CM2 Power plant Share facilities for CM1 and CM2 Power plant are listed below:

1. Supplementary Cooling water (CW): CW intake canal is enough for 2 power plants. 2X100% CW supply pumps for each plant.

2. Water supply:

Demineral water treatment: Treatment process is located at CM1 power plant with capacity of 3X50% for 2 plants (standby equipment) and treated water is stored in 02 tanks with capacity of 800m3 at CM1 power plant and in 01 tank of 800m3 capacity at CM2 power plant;

Domestic water: Domestic water for both plants is treated at CM1 power plant, treated water is stored in tank of 150m3 and then pump to storage tank at CM1 power plant and is used for both plants;

Service water: is pumped from CM1 power plant to upper storage tank of CM2 power plant;

Fire fighting water supply: is supplied from fire fighting system of CM1 power plant.

3. Wastewater treatment: capacity of CM1 wastewater treatment system (WTS) is increased for both plants, wastewater of CM2 power plant is pumped to WTS of CM1 power plant to treat and discharge together with CM1 power plant.

4. Cl, HCl system: located at CM1 power plant and supply for both plants

5. pH control system for supplementary cooling water: located at CM1 power plant.

6. DO fuel supply: install two oil storage tanks of 2x5000 m3 at CM2 power plant, two of which have pipeline to oil jetty and connect with 2 oil storage tanks of CM1 power plant.

7. Warehouse: is shared for both plants and located at CM1 power plant.

8. Repair workshop: is built at CM1 power plant.

9. Specialized tool: big specialized tool is shared for both plants.

2.2.3.2 Cooling water System Similar to the CM1 Power Plant, the cooling system of Ca Mau 2 power plant is closed circulation type. Excess heat from the main condenser and the auxiliary cooling system will be transferred into the cooling water, which will be cooled at cooling towers. The recirculation process of cooling water is maintained by the main cooling pumps. Any water loss in the closed circuit system – mainly due to evaporation and tower blowing down- will be compensated by the additional water supply system with maximum flow rate Vmax=3.600m3/h. The cooling water system is presented in Figure 2.4. a) Main Cooling Water System The main cooling water system of Ca Mau 2 power plant consists of:

• The main cooling water pump station • The main cooling water pipelines

The main cooling water pump station is installed at water storage tank of the cooling water tower. Water is pumped from storage tank to the condenser and heat exchangers of the additional cooling system via two main cooling pumps. Upstream of the condenser, a pipeline cleaning system is provided in order to protect against block-ups and loss of heat conductivity.



Main cooling water pumps have the following design parameters:

• Total nominal flow rate: 10 m3/s • Cooling water pump configurations: 2 x 50% • Flow rate of each pump: 5 m3/s • Water pipeline diameter: 2,200 mm

Forced cooling water towers (equipped with blowers), with shared chamber configuration, are selected for the Ca Mau 2 power plant. Design data of the cooling tower:

• Number of chamber: 8 • Circulation flow: 35,835 m3/h • Hot water temperature (intake): 45°C • Cool water temperature (outlet): 35°C • Wet bulb temperature: 25°C • Relative humidity: 85.17 % (according to wet chamber temperature) • Drift loss (% of circulation): 0.0005 % • Evaporation loss (designed) 1.61 % • Design wind pressure (for construction): 1.00 kN/m² • Atmospheric pressure: 1,013 mbar

The operating principle of forced cooling tower is summarized as follows: Air flow generated from blower will be entering from the tower bottom, traveling upward and passing through heat exchanging panels. Water will be sprayed from the tower top, moving downward and exchanging heat with air flow, mainly due to the evaporation process. Heat exchanging panels installed at tower middle will improve the heat transfer efficiency between the water and the air flow. Resulting from the heat exchange with wind, water entering the tower having a temperature of 45oC will be cooled down to 35oC at the tower outlet in normal operation. When tail gas incident occurs, inlet temperature is 52.3oC and outlet one of about 40oC. b) Additional Cooling Water Supply System Additional supply water for the main cooling water system is taken from the Cai Tau River through a canal system and pumping station shared with Ca Mau 1 power plant. The intake canal and storage basin of the additional water pumping station is designed with the criteria presented in Table 2.2.

Table 2.2 DESIGN PARAMETERS OF ADDITIONAL COOLING WATER SYSTEM

Parameters Value Design flow (m3/s) 2 Water velocity in canal/pumping basin (m/s) 0.3 – 0.5 Bottom canal elevation (m) - 3.40 Canal area (m2) > 6 Canal width (m) 4 Minimum water level/canal depth in low tide (m) - 0.90 / 2.50 Minimum depth/ intake width (m) - 4.0 / 6

Source: General Report of investment project for Ca Mau 2 Power Plant- volume 1- December, 2005 In order to prevent debris coming along with water, screenings will be provided at the transition place at the intake gates of the canal and the pumping basin. In front of the screenings, there are installed with blocking panel to isolate the canal during maintenance.



In order to prevent oil penetrating from the river and/or the adjacent fuel import jetty, these blocking panels will be positioned in such the way that the fixed upper part of the panel will block the oil. At the additional water supply pumping station at the end of the canal, screenings will retain debris before water is pumped to the cooling water basin (circulation). Because the water quality of the Cai Tau River is acidified in the rainy season, it is required to treat the cooling water used for supplying and cooling by:

• Injection of NaOH solution to control pH • Injection of H2SO4 solution and anti-scaling agent • Clorination

c) River Water pH Control System The river water pH control system comprises of 2 dosing pumps, 2 caustic soda (NaOH) tanks, connecting pipes, valves and control equipment. During the rainy season (from end of May to September), when Cai Tau River water has a pH lower than 5.5 (about 3.0 – 4.0), the intake water will be injected with NaOH solution (caustic soda) to raise the pH to the safety level of 5.5-8.0. The caustic soda solution (30% or 50%, or similar to water treatment solution) will be stored in 2 (or 3) tanks. The capacity of these tanks will adequately supply the NaOH 50% solution in two weeks. The tanks will be constructed beside the clorination facility (outdoor) and the dosing pumps are roofed. The NaOH solution will be injected into the supply pipeline by the dosing pump, in which the solution will be diluted by water to yield the final diluted solution. At the cooling water intake gate, this solution will be dispersed via diffusers in order to create a good dispersion in the canal. With the water velocity in the canal of the addition cooling water system is 0.3-0.5 m/s (and the canal length of 200m), there is more than 6 minutes for the NaOH solution to mix with water before the cooling water flows to the pumping basin. d) Sulfuric Acid and Anti-Scaling Injection System The system consists of 2 acid dosing pumps. 1 sulfuric acid storage tank, 2 anti-scaling agent dosing pump, 1 anti-scaling agent storage tank, connecting pipes, valves and control equipment. Sulfuric acid will be injected/sprayed into the cooling water basin to protect against scaling and maintain the pH of water below 8.0, usage dose varies in range of 40 – 100 g of sulfuric acid per a cubic metre of supply water. The sulfuric acid injection process will be monitored by a pH meter. Sulfuric acid with concentration of 98% will be used. The anti-scaling agent will be injected into cooling water for prevention of scaling/corrosion at surface of heat exchangers.



e) Chlorination System The chlorination station will protect the cooling water systems of the power plant against the development of aquatic organisms such as algae, mollusks, and etc. which can block heat exchanging surfaces and reduce the operating efficiency of relevant systems and equipment. Active chlorine can be provided as free chlorine (Cl2) or hypochlorite solution. Available free chlorine in the market has the liquidified gas form and is stored in high pressure tank. Chlorine will be fed to the spraying system from storage tanks each has a capacity of 1 tonne. The chlorination system includes 4 chlorination chambers, 4 chlorinators, 2 evaporator, 4 storage tanks, 1 chlorine-leak detector, connecting valves, control equipment, and protective gears such as gas masks and compress air inhalation equipment. f) Cooling Water Monitoring At the water basin of the cooling tower, pH and conductivity will be continuously monitored. Monitoring equipment will be installed in the on-site sampling panel. In monitoring of the blow down water from cooling tower, the remaining chlorine will be analyzed to control the chlorine content in discharged water. 2.2.3.3 Gas supply system for power plant Fuel of the power plant is natural gas. Natural gas is routed via the pipeline from PM3 gas field to the gas distribution station. At the gas distribution station, natural gas is pre-treated, dried from water and other liquids, dust filtering, and pressurizing to 40-60 bar as technical requirement of the power plant. From the gas distribution station, natural gas is distributed by separate pipeline to the Ca Mau 1 power plant 1 and Ca Mau 2 power plant. The gas received at the plant front-end is dry and clean gas. Estimation of gas demand for the power plant is presented Table 2.3 and gas characteristics are presented in Table 2.4.

Table 2.3 ESTIMATION OF GAS DEMAND OF THE PLANT

Operation time Unit Gas from PM3 Field Gas from Block B 1-hour maximum Thousand m3 132.84 146.32 1-day average (20 hours) Thousand m3 2,656.75 2,926.45 1-day maximum (24 hours) Thousand m3 3,188.10 3,511.74 1-year

5000 hours Thousand m3 664,186.86 731,612.18 5500 hours Thousand m3 730,605.54 804,773.40 6000 hours Thousand m3 797,024.23 877,934.62 6500 hours Thousand m3 863,442.91 951,095.84 7000 hours Thousand m3 929,861.60 1,024,257.06

Source: General Report of investment project for Ca Mau 2 Power Plant- volume 1- December, 2005



Table 2.4 INPUT GAS CHARACTERISTICS OF THE POWER PLANT

No. Characteristic Unit Value Note 1 Gas fraction 1.000 2 Temperature oC 20 above dew point At 40 bar 3 Pressure Kpag 4000 – 6000 40 – 60 bar 4 Molar flow Kmol/h 0 – 6206 5 Mass flow Kg/h 0 – 134630 6 Z factor 0.8162 – 0.8724 7 Viscosity cP 0.0127 – 0.0136 8 Cp/Cv 1.439 – 1.568 9 Molar weight 21.693

10 Density kg/m3 40.46 – 64.33 11 Standard volume flow m3/h 0.000 12 Standard gas flow Nm3/h 0 – 146738 13 Dew point temperature oC -8.8 ÷ -5.77 14 Dew point temperature of

Hydrocarbon oC 9.47 – 9.86

15 Water mg/m3 76.97 16 C6 hydro % mol 0.0020 17 Methane % mol 0.7795 18 Ethane % mol 0.0678 19 Propane % mol 0.0403 20 i-Butane % mol 0.0118 21 n-Butane % mol 0.0091 22 i-Pentane % mol 0.0039 23 n-Pentane % mol 0.0023 24 H2O % mol 0.0001 25 CO2 % mol 0.0753 26 N2 % mol 0.0079 27 High calorific value MJ/m3 41.6 28 Low calorific value MJ/m3 37.7

Source: General Report of investment project for Ca Mau 2 Power Plant- volume 1- December, 2005 After the gas receiving point, an emergency stop valve will be installed. The fuel gas distribution system includes dust and liquid separators, collectors, condensate collector, metering equipment and the pre-heating system (if required). a) Stop Valve (Emergency Valve) Stop valve is installed behind the gas receiving point, which must be able to isolate the whole gas distribution system of GTs in an emergency case. Stop valve must be remotely operated with close and open functions are activated manually from the Center Control Room. b) Dust-Liquids Separator Two dust-liquids separators (2x100%) will remove dust and liquids in the natural gas. Dust and liquids will be separated by cyclones. c) Gas Venting It is not required to install a flare for the power plant because the excess gas will be flared at the gas distribution station located at the South of the plant. The plant will be equipped with



gas venting pipelines for the gas distribution system. These vents will be positioned safely above the ground in order disperse emissions into the atmosphere. d) Metering Station The metering station will measure and log the gas quantity used by the power plant. The pipeline metering system will measure the temperature and pressure independently, which are used to convert the quantity of gas from actual pressure to standard pressure. e) Dust filter After each dust-liquids separator, 2 dust filters (2 x 100%) will be installed. The dust filter is applied modern technology to remove dust, rust, and other solid contaminates from dry gas. f) Pre-heating System In case the gas turbine manufacturer requires gas temperature above 20oC greater than the dew point, the use of pre-heating system is also required. The pre-heat of gas will prevent the hydration, which can affect negatively to gas firing equipment. When operating the combined cycle process, the pre-heating is indirectly undertaken by hot water extracted from the IP economizer. The minimum gas temperature must be 20oC higher than the dew point of water or hydrocarbons. The gas distribution system is presented in Figure 2.5. 2.2.3.4 Fuel Diesel Oil System When there is an interruption in gas supply, the plant will have to use fuel. However, the plant will use DO having low sulfur content to reduce the SOx and dust emissions. Besides, when operating, the plant will use DO for a few days only throughout the year. The DO utilized for the power plant is the distillate oil meeting technical criteria of ASTM No.2 standard. Table 2.5 CHARACTERISTICS OF DIESEL OIL (DO) USED FOR CAMAU 2 POWER

PLANT

Value No. Properties Min Max Unit Note

1 Colour - 2 Density @ 15 °C 876 kg/m3 3 90% distillation temperature 338 °C 4 Flash point 38 °C 5

Sulfur content 0.5 %wt

Maximum allowable of TCVN 5689-

2005 is 0.25%kl

6 Nitrogen ppm 7 Corrosion 3 h / @ 10°C No.1 - 8 Viscosity @ 40 °C 1.9 4.1 cSt 9 Freeze point - 6.0 °C

10 Carbon residue of 10% distillate 0.35 %wt



Value 11 Ash 0.01 % 12 Na + K 0.5 ppm

0.5 2.0

13 Total heavy metal - V - Pb - Ca

10

ppm

14 Water and residue 15 %vol 15 Low calorific value 42.5 MJ/kg

Source: General Report of investment project for Ca Mau 2 Power Plant- volume 1- December, 2005 According to the calculated data for the maximum sulfur content of 0.5%, the concentration of SO2 at stack top is about 277 mg/Nm3, still lower than the discharge standard for power industry TCVN 7440-2005. However, when operating with DO, the Ca Mau 2 power plant will still use DO having sulfur content lower than 0.5%. The DO storage and distribution system of CM2 power plant consists of 2 storage tanks, each of which has capacity of 5.000 m3, oil recovery basin, main oil pump system, auxiliary pump system and oil pipelines. The two oil storage tanks are connected with the oil storage facility of CM1 power plant. The estimated DO demand of the plant is presented in Table 2.6.

Table 2.6 ESTIMATED DIESEL OIL DEMAND OF THE PLANT

Operation time Unit Fuel quantity 1-hour maximum Tonne 108.52 1-day average (20 hours) Tonne 2,170.48 1-day maximum (24 hours) Tonne 2,604.58 7-day average Tonne 15,193.38 7-day maximum Tonne 18,232.05

Source: General Report of investment project for Ca Mau 2 Power Plant- volume 1- December, 2005 Oil from storage tanks is delivered to gas turbines via the oil pumping system including pumps; double filters, isolating valves, 1-way valves, pressure gauges, and pressure switches behind and in front of the pump. 2.2.3.5 Potable Water System For every demand of technical water of the plant, potable water will be supplied from the Ca Mau Water Supply and Drainage Company to the plant front-end, and then directed to the potable water tank. The Ca Mau 2 power plant will be water-connected with the Ca Mau 1 Power Plant. Potable water is supplied for following systems:

• Dematerialized water • Domestic water/ service • Water for other purposes

List of potable water demand of the Ca Mau 2 power plant is presented in Table 2.7.

Table 2.7 POTABLE WATER DEMAND OF CA MAU 2 POWER PLANT

Description Unit Average demand Demineralized water m3/day 665.98 Domestic water m3/day 51.84 Other purpose water m3/day 51.84 Total M3/day 769.66

Source: General Report of investment project for Ca Mau 2 Power Plant- volume 1- December, 2005



2.2.3.6 Demineralized Water Supply System The demineralized water system will be shared with the Ca Mau1 Power Plant. The demineralization station will produce and supply demineralinized water to:

• Additional water for the condenser of steam turbine • Additional water for closed circuit cooling facilities of the auxiliary cooling system • Water for heat recovery systems • Water for cleaning compressors • Water for injection combustion chamber of gas turbine (for low-NOx burners when

using DO) • Water for chemical injection systems • Water for filling up the HRSG

Capacity of the additional demineralized water system for Ca Mau 2 power plant is 25 m3/h, the treatment process of system includes 2 stages: Reverse Osmosis (RO) and Ion Exchange. Water before entering the RO will be added anti-scaling agent and dechlorination to avoid membrane scaling and oxidizing. 2.2.3.7 Wastewater Treatment System In order to share facilities for 2 power plants for economizing investment expenditure, industrial wastewater treatment system will be used for both plants and located at Ca Mau 1 power plant – with enough capacity for both CM1 and CM2 power plant. The share wastewater treatment system consists of storage basins made of waterproof concrete.

• 1 oil-water separating basin • 1 wastewater storage basin • 1 neutralization basin • Pumps, pipelines, valves and control equipment.

Industrial wastewater of the CM2 power plant will be pumped to the share wastewater treatment system located in the CM1 power plant through separated pipeline system. Treated water met environmental standards will be discharged at the same industrial discharged location of CM1 power plant to the Cai Tau river. Detailed descriptions of the wastewater treatment system will be presented in Section 6 of this report. 2.2.3.8 Electricity System a) 220 kV Switchyard The voltage of 220 kV is selected for Ca Mau 2 Power Plant to tie-in with the power network of EVN. The outdoor 200 kV switchyard is designed with 1-breaker configuration. The layout of the switchyard is presented in Figure 2.6. Ca Mau 2 Power Plant will be connected with the national grid at 200kV-voltage via the 220kV transformer of Ca Mau 1 Power Plant. Additional transmission lines for Ca Mau 2 Power Plant are:

• A single 220 kV line Ca Mau – Bac Lieu • A double 220 kV line Ca Mau - Rach Gia • A single 220 kV line to Ca Mau Transformer Station • A single 220 kV line Ca Mau – Soc Trang



b) Self-Power System The power for the whole plant own usage is rooted from 2 self-transformers installed at the breaker between two gas turbines. The self-power consumption rate makes up of 2-3% of the generation capacity, equivalent 22.5 MW. The self-power system of the plants includes:

• The AC system which comprises a mid-voltage (6.6kV supplied for engine and machine > 200kW such as pumps) and a low-voltage system (0.4 kV supplied for machine and engine < 200 kW and control center);

• Main self-transformers (2 x 23 MVA), magnetic-activated transformers of gas turbines and steam turbine and unit-self usage (3 x 1.6 MVA), HRSG transformers (2 x 2 MVA), and plant-shared transformers (2 x 2 MVA);

• The emergency diesel generator of 400 kV with capacity of 750 kW;

• The DC system for control and supervision and supplied for DC engines. Tentatively, there are 2 voltage levels which are 220V (supplied for engines, controls, emergency lightning, and protection switches) and 48 V (supplied for communication system, electronics, fire alarms and computers); and

• The Uninterruptible Power Supply (UPS) system

2.2.3.9 List of used Chemicals in power plant Major chemicals listed in Table 2.8 will be used for the whole operation phase of the power plant.

Table 2.8 LISTS OF USED CHEMICALS OF THE POWER PLANT

No Description Purpose Storage

Volume Rate

For Boiler 1 Phosphate (5% solution) Boiler 1.0 m3 30l/h 2 Hydrazin (1-2% solution) Boiler 0.75 m3 16l/h 3 Ammonia (1-2% solution) Boiler 0.75 m3

For Cooling System

4 Chlorine Treating cooling water 1

ton/container

4 times/day

5 Sulfuric acid (98%) pH control 1x50m3 40-100g/m3

add 70l/h.

6 Anti-scaling agent Protecting against scaling and corrosion 1x5m3 10l/h

7 Sodium hydroxide, 30-50% pH control 3x60m3

2x60m3 5-8.5m3/h

8 Hydro Chloride acid Demineralizing & Neutralizing 2 X 25m3 8m3/h

9 Caustic soda Demineralizing & Neutralizing 2 X 15m3 12m3/h

10 Chloride iron Neutralizing 2 X 15m3 6m3/h



2.2.3.10 Fire and Explosion Fighting System The plant is designed for operating safely to people and equipment. In order to achieve this target, equipments are arranged properly so that the risks of fire and explosion are minimized. The system is designed in compliance with American National Fire Fighting Association (NFPA) standards. Areas having risks in the plant are gas distribution station, storage tanks area, transformer area, lube oil tank, gas turbine combustion chamber and machine house The plant will be equipped with the following fight fighting systems:

• Fire detector and alarm • Automatic Sprinkler • Stationary Foam System • Mobile Foam System • Tank water-cooler • Firewater posts • Fire extinguishers

The fire and explosion fighting system is designed in compliance with Vietnamese standards and NFFA as following:

• Maximum water pressure: 14 bar • Fire water flow: 12.0 litres/m2/min • Deluging rate: 10.0 litres/m2/min • Foam rate is 4.1 litres/m2/min to protect for DO storage tank • Outside of the dyke surrounding oil storage area, there will be installed foam hoses

with flow rate about190 liters/min. The Ca Mau 2 power plant will share the fire-water pumping station with the Ca Mau 1 Power Plant. Water supply for the fire water system is from potable water storage tanks of 2 x 2000m3. Only the foam system will be newly built. Firewater posts are equipped along the distribution system with the interval of 80m. Tools and accessories are provided in box at each post, Portable fire extinguishers are properly placed inside machine houses and buildings of the plant for fire preventing and fighting demand.

• Indoor fire-water posts are placed at turbine house, cooling water pumping station, water treatment station, and control room, gas distribution station and oil pumping station.

• Deluging systems are placed at hydraulic oil/lube oil system area, transformer area and lube oil storage area

• Outdoor fire fighting water posts are placed at gas turbine area, HRSG area .

• CO2 systems are placed at electric instrument room and central control room.

• Foam systems are placed at oil tank area and oil pumping station Smoke detectors are equipped in electrical machine rooms. Heat detectors are installed in the lube oil system, the transformer area, and the tank area. Gas leaking detectors are installed at the gas distribution station and the gas turbine area.



2.2.3.11 Communication System The plant communication system has the following functions:

• Communicate among the plant, the national and the regional control centers • Communicate among controls and supervisions of the plant

The communication system of Ca Mau 2 Power Plant includes:

• The internal PABX directory system • Optic cables for data transferring between CM1 and CM2 Power Plant • Direct telephone line to the National Power Control Centre (A0), the Southern Power

Control Centre, O Mon Power Plant and 220KV transformer stations of Rach Gia, Bac Lieu and Ca Mau.

• Data channel for connecting the computer network of the plant to the computer network of EVN.

According to the project schedule, the Ca Mau 1 Power Plant will come into operation firstly. Therefore, the Ca Mau 1 Power Plant will host the communication and data transferring for both the plants. 2.3 CONSTRUCTION PHASE 2.3.1 Site Preparatory Works The construction site is prepared and leveled to +1.97m (at the boundary) and +2.84m (at centre) by geotextiling/vacuum pumping and geotextiling/consolidating. The site has surface loads of 2 – 8 tonne/m2 (depending on technical facilities) and a slope of 0.5 – 1.1% for drainage. 2.3.2 Plant Construction As designed, the Ca Mau 2 power plant will share some constructions with the Ca Mau 1 power plant such as the administration office, reparation house, storage house; … Major constructions of the Ca Mau 2 power plant will be newly built as follow. 2.3.2.1 Main Plant The main plant consists of gas turbine and steam turbine houses. The turbine houses are designed as 1-level with steel frame. The drainage basin and the submersible drain pump are installed at the lowest point of the house. The main plant is constructed on the reinforced concrete base, pile supported. Another reinforced concrete base will be used for installation of turbines and generators. Ventilation for the main machine house will be natural ventilation via openings on the roof and wall. The venting fan at the top roof is equipped with the automatic gas detector for detecting gas leakage inside the building. Fire fighting equipment includes indoor firewater hose, automatic CO2 deluge system, CO2 and chemical fire extinguishers and emergency exits. a) Main Transformer



b) Transformers, HRSG and Main Stack These facilities are constructed on outdoor reinforced concretes supported with piles. Oil collection basins are designed below transformers and pumps will be provided to pump out the oil in emergency case. Discharged water is directed to the oil separation basin of the wastewater treatment system. The supporting frame of the stack is steel and 40 meters high for the main stack. c) Control Unit The central control unit comprises of main control room, server room, working room, DCS room, staff room, toilets, switch room and battery room. The control unit is also equipped with the fire fighting equipment, which are firewater hose, automatic CO2 deluge system, CO2 fire extinguishers and emergency exit and staircase. d) Fuel Storage The fuel storage includes 2 x 5.000 m3 oil tanks made by steel plates. All solders are inspected by sonic waves. Surrounding the oil tanks, earth embankment covered by waterproof concrete is constructed to avoid oil spill. The tank site is steeped and equipped with storm water/oily water channel directing to the oil separation basin before conduct to discharged system. 2.3.2.2 Wastewater Treatment System The Wastewater treatment unit comprises of these following facilities/areas:

• Demineralized water • Potable water • Chemical storage • Wastewater treatment • Electricity • Toilets • Labs • Working quarter • Basin and tank area

Besides water treatment unit, tank area, the Wastewater treatment works include:

• Wastewater basin • Neutralization basin • Treated water basin • Oil separation basin

2.3.2.3 Cooling Water System New-built system will be:

• The main cooling water pump station • The main chlorination system for cooling water

The main cooling water pump station has steel frame design with area of 14 x 17 m, comprising pumps, pipelines and accessories. All buildings above the base (floor and wall) are waterproof concrete and pile supported. The whole construction is protected against corrosion and has a metal roof without heat resistance cover. 2.3.2.4 Switchyard



The 200kV switchyard of Ca Mau 2 Power Plant is tied-in with the extension of Ca Mau 1 Power Plant switchyard in order to connect to the power grid easily. Gates, bars and carriers are made of steel coated with zinc by the hot dipping method, which are manufactured in the warehouse and fabricated on site. These structures will be joined by bolts, which are produced in compliance with Vietnamese Standard TCVN 102–73 and TCVN 62–73, and tested before exported. All incoming and outgoing lines of the switchyard will be installed inside the concrete canal. A safety mesh fence with the height of 1.8m will be implemented around the switchyard. 2.3.2.5 Road system The road system consists of domestic roads and interconnecting roads to traffic way outside the plant. The domestic roads are designed so that the transportation among facilities is the most convenient and shortest. Traffic ways outside the plant are expected to be incorporated into the Ca Mau integrated gas- power – fertilizer area.

• Road for heavy machine transportation, 9 – 10m width; • Road for 40-tonne lorry, 8m width; • Road for light transportation, 4m width; • Road for pedestrian, 1.5m width; • Parking area

Buildings and areas are arranged in an appropriate distance, and tree lanes are provided among them to minimize dust and noise and to enhance shadowness. Roads will be constructed properly to each area type and made of reinforced concrete, configured to include 3 layers: rocks at the bottom, macadam in the middle, and concrete/asphalt layer on the top. 2.4 PROJECT DISCHARGE SOURCES 2.4.1 Emissions In normal operation, the power plant will use gas as fuel source. This is a clean fuel and the pollutants are only CO and NOx; SOx is almost none. When the plant uses DO for fuel, major pollutants are CO, NOx, SOx and dust. Load (calculated for 1 stack) is 674m3/s (with natural gas) and 736 m3/s (with DO). The EPC contractor will ensure emission rates always complying Vietnamese discharge standards. 2.4.2 Effluents Effluents of the plant are categorized as regular and non-regular effluents. Loads of these effluents are detailed in Section 4. 2.4.3 Solid wastes Solid wastes of the plant can be separated as industrial and domestic wastes:

• Industrial waste: Solid industrial wastes include packaging, oily rags, and sludge from water treatment. These waters are categorized for reuses. Disposal fraction will be collected and transferred to the landfill, or contracted with the provincial water supply and urban sanitation company for disposal.

• Domestic waste: Domestic wastes include garbage from living quarters, public areas, canteens and sludge from septic basins.

2.5 INVESTMENT FOR ENVIRONMENTAL PROTECTION



During implementation, project owner always estimates a part of budget for environmental protection works including:

- During the construction, installation and commissioning phases of the plant: budget for the environmental protection works includes in EPC contract of the power plant. All treatment system will be completed in the commissioning phase.

- In the operation phase: expenditure for the environmental protection works includes into operation cost of the power plant.

In practical, project owner has paid much attention to environmental protection issues even from feasibility study phase and technical design. All necessary equipment to mitigate environmental impacts have been invested such as safety system; Fire fighting and prevention equipments, wastewater treatment system, and solid waste collection and treatment system… Due to CM2 power plant is one part of Ca Mau Power plant complex, so some facilities in which environmental protection ones will also be shared for both plants such as: Fire fighting and prevention system, laboratory…Environmental protection facilities separately installed for CM2 power plant are shown in Table 2.9.

Table 2.9 ENVIRONMENTAL PROTECTION FACILITIES OF CAMAU 2 POWER PLANT

No Facilities Note

1 Waste water collection and treatment system (WTS)

Belongs to invest budget of WTS for both CM1 & CM2 PP

2 Valves and spare parts supplied fire fighting water for CM2 PP.

Belongs to budget for share Fire fighting and prevention system of both plants.

3 Equipments for air emission monitoring at top of main stack.

Belongs to budget for stack complex

4 Solid waste collection and treatment Will sign contract with Ca Mau Water supply and urban sanitation following by current price.

In the operation phase, the plant will have HSE staff. Especially, to ensure safety for plant operation activities, all employees working in the plant will be trained in safety and environmental protection issues. These training courses will concentrate on individual responsibilities for each worker during safety and environmental protection maintain process at working place of labours and its vicinity area. Environmental protection works include expenditures for planting green tree and establishment green belt at the plant boundary. This expenditure is included in budget of EPC contract. During the operation phase, project owner will strictly comply with the Government Decree No 67/2003/NĐ-CP on the environmental protection fee for wastewater. 2.6 PROJECT SCHEDULE



Major milestones of the project/power plant schedule are presented in Table 2.10.

TABLE 2.10 SCHEDULE OF CA MAU 1 & 2 POWER PLANTS

CM1 Power Plant CM2 Power Plant

No. Work Duration

(month) Start End Duration

(month) Start End

1 Tender and Bidding for EPC Contractor 01/2006

2 Award EPC Contract <1 11/2005 11/2005 <1 02/2006 02/2006 Implement EPC Contract 25 11/2005 12/2007 25 02/2006 03/2008

Site Preparation 24 03/2005 03/2007 6 12/2006 06/2007 Construction

Equipment installation 17 03/2006 08/2007 19 04/2006 11/2007

Open cycle operation 4 03/2007 07/2007 Combine cycle Commissioning 4 08/2007 12/2007 3 11/2007 02/2008

Plant temporary Licensing 1 12/2007 12/2007 1 03/2008 03/2008

3

Plant Transfer 1 12/2007 12/2007 1 03/2008 03/2008



Section 3.

EXISTING ENVIRONMENT OF THE PROJECT AREA AND ITS VICINITY

The main content of this section is to describe the environmental characteristics of the project area and its vicinity. The information will provide the basis for assessing potential environmental impacts caused by project implementation as well as a basic reference for future monitoring program. Due to Ca Mau 2 power plant is located on the planned land for fertilizer plant, where the Southern part is adjoined to Ca Mau 1 power plant at Khanh An Commune. The description of existing environment is based on the field monitoring results and analysis samples collected from 19 - 24/12/2005 and compared with the results in the EIA (Environmental Impact Assessment) report of Ca Mau 1 power plant in 2002. 3.1 SCOPE OF PROJECT AREA The Ca Mau 2 power plant is located in ward 3 & ward 1 of Khanh An Commune, U Minh District. Its Northern part is bordered on Ca Mau 1 power plant, the Eastern one is closed to Cai Tau confluence and the Western part is bordered on the Cai Tau K1 prison land (Figure 3.2). The project 's vicinity area in the space of 10km radius includes Tac Thu sluice, Cai Tau residential area, K1 Prison, Khanh An's resettlement area, Vo Doi Specific Forest, U Minh III and Tran Van Thoi forestry farms. 3.2 PHYSICAL ENVIRONMENT CHARACTERISTICS 3.2.1 Climate characteristic [2] Meteorological data of the project area is referred to the survey data in many years at Ca Mau Meteorological Station, located about 12.5 km far from the project area in the Southwest direction. 1. Temperature According to the statistical data during 1980 - 2004 at Ca Mau Meteorological Station, the annual average temperature is high (27.2oC). The variation ranges from 25.6 to 28.5oC. In the hottest month (April), the average temperature is from 27.7 to 29.8oC, and the variation is from 24.8 - 27.2oC in the coldest month (January). The temperature difference among months within a year is about 2.9 - 3.4oC. The daily highest different in the dry season is about 7-8oC, and the lowest in the rainy season is about 6 - 7oC. The absolute highest temperature is 37.8oC; the absolute lowest one is 16.20C and this remains in a short period of day. The monthly average temperature in the duration of 1980 - 2002 is showed in Table 3.1.



Table 3.1 STATISTICAL MONTHLY AVERAGE METEOROLOGICAL DATA AT CA MAU STATION (1980 - 2004)

Month I II III IV V VI VII VIII IX X XI XII Year

Temperature (oC) 25.6 26.1 27.4 28.5 28.3 27.7 27.5 27.3 27.1 26.9 26.8 25.9 27.2

Humidity (%) 78.6 78.1 76.5 77.1 82.1 85.0 85.1 86.4 86.8 87.0 83.7 80.2 82.2

Pressure (mb) 1012.2 1011.6 1010.5 1009.1 1008.7 1008.1 1008.2 1008.4 1009.0 1009.5 1010.2 1011.6 1009.8

Sunshine hours *

226.1 212.7 253.2 226.4 168.8 145.5 152.5 137.9 140.5 137.8 169.9 197.4 2168.6

Solar radiation (Kcalo/cm2) ** 452 470 530 459 388 364 372 362 370 359 375 373 406 Source: Southern Region Hydrometeorological center, 2005 Note: (*) from 1996 – 2004; (**) from 1996 – 2001

The statistical data shows that the monthly average temperature in the duration of 1980 - 2004 at Ca Mau is relatively high and stable. 2. Humidity

Humidity of the study area is closely related to rain and wind regime. The average relative humidity is quite high (82.2%). The relative humidity peaks at 87% in October (rainy season) and the lowest one is at 76.5% in March (dry season). The observed absolute lowest humidity is 40% in 1958. In the rainny season lasting from May to November, average humidity is about 82 - 87%. In the dry season, except December has, average humidity more than 80%, almost other months (from January to April), average humidity is lower than 80% (Table 3.1). The difference of humidity between the wettest month and the driest month is ranged from 9% to 11%.

The highest relative humidity in the duration of 1980 - 2004 is 90% (October, 1980), the lowest one is 71% (March, 1998), the annual average one is 82.2%.

3. Air Pressure

Based on the statistical data from 1980 to 2004, the annual average pressure was 1,009.8 mbar (Table 3.1), the variation is not much between months. The differences of air pressure among regions are not much. Therefore, it makes the balance and stability of the meteorological conditions in this area.

4. Sunshine

Ca Mau is located in the area where the average sunshine hours are quite high, the total annual average sunshine hours are 2,168.8 with about 6.8 - 7.5 hours/day. In the dry season, the average sunshine hours are 7-8 hours/day, equivalent to 219 hours/month. March usually has the highest average sunshine hours of about 253 hours/month, whereas October has the lowest one (137.8 hours/month) (Table 3.1). 5. Solar radiation

Solar radiation in the project area is rather high and stable with the average annual value of 406 Kcalo/cm2. 6. Evaporation

The annual average evaporation in Ca Mau is rather high about 973 mm (Piche). In dry season, due to high sunshine and low humidity, the evaporation is high and reaches the peak in March (124 mm). The deficiency of rainfall in comparison with maximum evaporation occurs in February (11 times higher than one in Ca Mau Station) (Table 3.2). In rainy season, the evaporation significantly decreases in comparison with the dry season. The lowest evaporation is only 52mm in October.



Table 3.2 COMPARISION BETWEEN THE AVERAGE EVAPORATION AND RAINFALL IN THE DRY SEASON (1980-2004)

Month Location Characteristic I II III IV XII Total Deficiency (mm)

Evaporation (mm) 100 99 124 105 87 614 Ca Mau Rainfall (mm) 18 9 32 97 88 231 383

Source: Southern Region Hydro Meteorological Center, 2005

7. Rainfall Annual rainfall The study area has a very high annual rainfall (2,484 mm in Ca Mau). The average number of rainy days in this area is quite high, approximately 163 - 171 days at Thoi Binh, 171 days at U Minh and 167 days at Ca Mau. Annually, there is about 1 rainy day per 2 days. Seasonal and monthly rainfall Monsoon regime has brought 2 distinguished seasons: rainy season and dry season. In general, the rainy season lasts 7 months from May to the end of November, which is the same time with Southwest monsoon season. In this period, the percentage is about 82 - 91% in comparison with the annual rainfall. Dry season begins in December and ends in April in next year. This period simultaneously occurs with Northeast monsoon season, which has only 9 - 18% of total annual rainfall (Table 3.3). Especially, sometimes, rainy season comes quite soon (1999), or very late (1998).

Table 3.3 ANNUAL AND SEASONAL RAINFALLS IN CA MAU

Rainy season (V-XI) Dry season (XII-IV) Station

Annual Rainfall (mm) X(mm) (%) X(mm) (%)

Notes

Ca Mau 2,484 2,222 89.5 262 10.5 1980-2004 U Minh 2,471 2,025 82 446 18 1984-2001 Thoi Binh 2,330 2,078 89 252 11 1984-2001

Source: Southern Region Hydro Meteorological Center, 2005 In the rainy season, the monthly average rainfall gradually increases from May (above 250mm and rainy days are higher than 11 - 15 days). The highest rainfall is observed from July to October (higher than 300mm of rainfall and 19 - 23 rainy days). In November, the average rainfall is decreased, in general it is only about 150mm with 10 - 12 rainy days. Variation of monthly rainfall is very high, particularly at the beginning and at the end of rainy season. There are about 10-25% of the observed years in which the annual rainfall was 1.5 times higher than ones in the same period (Table 3.4).

Table 3.4 THE MAXIMUM MONTHLY RAINFALL (MM) IN CA MAU IN COMPARISON WITH THE STATISTICAL MEAN VALUES (1960-2004)

Month Characteristic I II III IV V VI VII VIII IX X XI XII

Max 116 81 173 446 556 594 601 589 702 749 374 309 Average 18 9 32 97 290 306 330 343 337 332 170 88

P(%) 13 10 26 10 10 3 3 13 3 3 16 10 Source: Southern Region Hydro Meteorological Center, 2005 Notes: Max : highest monthly rainfall (mm) Average : average monthly rainfall over the years (mm) P% : percentage (%) of year number having higher value of monthly rainfall in comparison with the average ones



In the dry season, except the first and the last months (December and April), the rainfall is about 50 mm with 5 - 10 rainy days. The monthly rainfall in the middle of this period is approximately 10 mm with 1 - 2 rainy days (Table 3.5). Significant deficiency of fresh water usually happens in this period.

Table 3.5 THE AVERAGE RAINFALL (MM) IN CA MAU STATION

Month (mm)

Station Year (mm) I II III IV V VI VII VIII IX X XI XII

Notes

Ca Mau 2352 18 9 32 97 290 306 330 343 337 332 170 88 1960-2004

Thoi Binh 2330 14 27 31 133 272 335 328 331 322 323 167 46 1984-2001

U Minh 2471 20 25 64 167 236 286 355 348 340 304 156 45 1984-2001 Source: Southern Region Hydro Meteorological Center, 2005 In general, the project site is located in the area where the annual average rainfall is very high. However, the rain distribution is unequal within a year, therefore it causes water redundancy in the rainy season and water deficiency in the dry season. With the long dry season, it causes serious drought situation, which is a potential risk of forest fire, for example at U Minh Ha Melaleuca forest fired in March and April 2002. 8. Wind

There are 2 monsoon seasons per year: Northeast monsoon season often occurs from November to April, and Southwest monsoon season is from May to October. Northeast monsoon season including mainly Eastern wind occupies 50-70% of frequency within a month with the average wind velocity of 3.3 m/s (in February), the maximum wind velocity was 28.0 m/s (East direction, occurred in November, 1997 in Ca Mau). Southwest monsoon season is mainly generated by West direction (about 40 - 50% in monthly frequency) with the highest average wind velocity of 1.8 m/s. In this period, the highest wind velocity was 28 m/s. Wind roses of Ca Mau area is presented in Figure 3.1. 9. Special Climatic Phenomena Generally, storms and tropical low pressures scarcely land directly to the coastline of the Mekong Delta area. Because local people do not have the custom of storm prevention and protection, moreover, due to low and flat terrain, so the storms landing often cause great damages in a large area. In the period of 1997 - 1999, there were some typical storms such as storm No.5 (LINDA, 1997), tropical low pressures or the storm No.7 (1998), the storm No.10 (1999) landed to the inland or to the coast then be weaken. The damage caused by storms is severely, for example, the storm No.5 landed to the coastal zone of the Mekong Delta in November 5th, 1997. It landed directly to Ca Mau with rainfall of 278 mm in 10 days (from November 1st to November 9th) and it is 2 times higher than the usual average rainfall in November. In 1999, rainfall in Ca Mau is unusual, precipitation in April is at a high level (447mm, 4 times higher than the average value at the same time in many years). In June, rainfall is highest in a year (496mm) that higher than the average one in many years at the same time (324mm) is 172 mm. In October, the second rainfall peak of the year, rainfall in October, 1999 is 476mm, in which rainfall in the last 10 days of October is 264mm. These special climatic phenomenons are main reasons caused storms, heavy rain, great damages to properties and human living in the Mekong Delta.



The storm No.4 at the end of 2004 caused some damages to properties. There were 180 damaged houses and 03 damaged classes in Ca Mau City, 03 roofs - blow up houses in Nam Can, and 71 families were influenced due to unsteady irrigational embankment which made water flooding the agricultural land and lost farm products, fruits and cattles with total damaged value of 250 millions VND [3]. At the beginning months of 2005, prolonged drought caused droughts at some places in the area affected to agriculture production (fruits, farm products...) and fishery aquaculture (shrimps were infected by diseases and died by salinity increasing in a large area) [3]. 3.2.2 Air quality in the project area [4] To assess air quality at the CM2 power plant area and its vicinity, RDCPSE had conducted measurement and analysis of air quality and microclimate at 3 sites (Figure 3.2). The measurement was carried out during the period of 19-24th December, 2005. The analytical results of air quality at the project area and Cai Tau residential area are given in Table 3.6.

Table 3.6 ANALYTICAL RESULTS OF AIR QUALITY (day average) AT PROJECT AREA AND CAI TAU RESIDENTIAL AREA IN 2005

Parameters (mg/m3) Sampling site

H2S CO NO2 SO2 O3 NH3 Pb VOC Dust

CM 2 Power Plant area

CM2 power plant (KK1)

0.0012 2.1356 0.0140 0.0199 0.0417 0.0281 <0.01 <0.05 0.238

1600m far from CM1 power plant 's stack to Southern direction (KK2)

0.0015 2.1835 0.0118 0.0191 0.0437 0.0283 <0.01 <0.05 0.216

CM2 power plant – measured in rainy season-2002

0.002 1.096 0.016 0.023 0.028 0.048 <0.01 <0.05 -

Cai Tau residential area Cai Tau residential area (KK3)

0.0021 1.938 0.0148 0.0248 0.048 0.052 <0.01 <0.05 0.234

Cai Tau residential area – measured in 2002

0.002 1.055 0.014 0.019 0.029 0.047 <0.01 <0.05 -

TCVN 5937-1995 (average 24 hrs) - 5 0.1 0.3 0.06 - 0.005 - 0.2 Source: RDCPSE, 2005

Because the air quality measurement were carried out at the beginning of the dry season (December, 2005) but the rainy season in 2005 ended lately, So the analytical results will be compared with the ones of air quality and microclimate at project's vicinity areas in the rainy season, 2002 which are shown in Table 3.6. Generally, the measured pollutants in the air increased, particularly carbon oxide (CO) and Ozon (O3) are high at all sampling sites. The reasons are due to the CM1 power plant is in the hastily construction period and the number of vehicles at Cai Tau residential area, Khanh An Commune is higher than that in 2002. However, the measured air pollutants were still lower than the ambient air standards of Vietnam except dust, which spreads from the construction area of CM1 power plant to CM2 power plant and Cai Tau residential area. It is noted that the sampling and measurement carried out at the strong wind time due to tropical low pressures occurred at that time. Noise and Vibration



The measured results of noise and vibration in the period of December, 2005 are shown in Table 3.7.

Table 3.7 PARAMETERS OF NOISE AND VIBRATION

Microclimate parameters No. Measuring site Date Measured Time Noise (dB) Vibration (dB)

1 9h30 68.4 76.4 2 12h00 57.6 70.2 3 14h10 57.7 89.3 4

20/12/2005

16h20 57.7 67.2 5 8h00 65.7 85.6 6 9h45 63.9 72.4 7 13h00 63.3 74.2 8

21/12/2005

16h30 62.0 70.2 9 8h00 63.0 86.5 10 10h15 63.7 67.4 11 13h15 57.9 65.4 12

CM 2 Power Plant (KK1)

22/12/2005

16h30 61.4 64.4 13 9h10 56.8 69.2 14 12h10 56.2 65.4 15 14h30 56.3 68.4 16

20/12/2005

16h50 65.5 69.6 17 8h00 56.3 75.6 18 10h10 67.3 89.7 19 13h10 54.4 72.1 20

21/12/2005

16h45 56.4 68.7 21 7h45 56.9 69.5 22 10h00 56.3 72.5 23 13h00 56.7 70.2 24

Distance of 1600m far from power plant 1's stack in Southern direction (KK2)

22/12/2005

16h20 55.8 69.9 25 8h00 66.8 72.3 26 11h15 67.2 76.7 27 14h00 57.5 69.1 28

20/12/2005

16h40 56.5 65.7 29 8h10 55.7 62.4 30 11h10 54.6 65.4 31 14h00 62.2 82.3 32

21/12/2005

16h40 66.8 75.6 33 8h15 66.9 72.4 34 11h00 63.6 76.9 35 14h05 63.6 69.8 36

Cai Tau residential area (KK3)

22/12/2005

16h45 62.4 68.9 Vietnamese Standards 75 (*) 75**

Source: RDCPSE, 2005 (*) TCVN 5949:1995 Applied for production area intermixed with residential area, from 6-18 hours. (**) TCVN 6962:2001 Applied for production area intermixed with residential area, from 7-19 hours.

The measured results of noise and vibration [4] at the project area in December, 2005 are lower than allowance limits. However, at some measuring sites at the CM2 power plant and



its vicinity, the measured results are higher than allowance limits because of the operation of constructive machines at the CM1 power plant. 3.2.3 Hydrology Regime and Surface Water Quality 3.2.3.1 Hydrology regime at Cai Tau Confluence Area The project area is a confluence of 3 main rivers including Ong Doc, Cai Tau and Trem rivers. Like other confluences, this area is affected by tide of southwestern sea, of Cai Tau River from U Minh Ha upstream and Trem River from Rach Gia estuary. Furthermore, West sea tide from Ong Doc estuary as well as East sea tide from Ganh Hao river through Tac Thu canal and other canals in southern of Chac Bang Canal also influences this area. Moreover, it is affected indirectly by Hau River. The tidal regime at Ong Doc rivermouth and Rach Gia is not phase-synchronization. Therefore, the variation of the current is very complex. Direct effects of West sea tides to the project area are as follows: - At the spring- tide, the main tidal direction is from Ong Doc river leading to strong effect

on Tac Thu confluence. At the Tac Thu confluence area, one tidal direction goes into Tac Thu river and another goes reverse up to Cai Tau confluence. Then, the tide continues going in by two directions: one to Cai Tau rivulet and another to Tieu Dua rivulet. Therefore, Tac Thu river is conjunction between East and West tides. The main water interface between East and West tides is slanting toward the Ong Doc river.

- At ebb-tide, the area from Cai Tau conjunction to Tac Thu conjunction, there are two

supplementary sources such as: from Trem, Cai Tau rivers and from Tac Thu river. As the result, tidal foot rises. Rising water phenomenon is mostly clear during heavy rain period, especially in October coincided with spring-tidal period (water level amplitude measured in October 1989 varied from 15 - 20cm), which not only limits drainage ability via the area but also limits that one of the U Minh Ha area generally.

- The tidal amplitude in this area is quite small. In the rainy season/ flood season, the

variation of tidal amplitude is from 20-30 cm. In the dry season/ ebb season, the tidal amplitude varies from 45-60 cm. The lowest tidal foot varies from -15 cm to -30 cm while the crest of tide drops down. In the flood season, the crest of tide varies from 50-60 cm.

Variation of water level and current after having Tac Thu dock: - When Tac Thu dock exists, some issues will be solved as: preventing salinity intrusion

from Ong Doc river to upstream, drainaging out acid water in June and flood water in October as well as keeping water for U Minh area and its vicinity.

- For upstream of Tac Thu dock: Average water level will be lower about 8-10cm in the dry

season (due to high water consumption), so west tide through Cai Lon rivermouth will intrude furthermore into Chac Bang canal, salinity water will intrude to Vinh Thuan area.

- For downstream area of Tac Thu dock: as high tide, water level at downstream of Tac

Thu dock is about 25 - 28cm higher than the one at upstream. Current passing through dock is one-way current and depends on operation of dock. Current characteristic at Tac Thu station is summarized in Table 3.8.

Table 3.8 SUMMARY OF CURRENT CHARACTERISTIC AT TAC THU STATION

Characteristics Flow rate Measurement period



09-23/X/1989 08-23/VI/1990 08-23/II/1990 21/II-08/III/2002 Hmax (cm) 65 52 50 40 Hmin (cm) 28 -15 -30 -13 Hbq (cm) 56 19 14 13 Amplitude (cm) 20 50 57 44 Q+max (m3/s) 120.2 61.5 54.9 95.3 Q-max (m3/s) -67.5 0.0 -47.6 -103.2 Qbq (m3/s) 36.3 31.4 15.6 7.2 Number of hour for down flow 14-16 hrs 20-22 hrs 14-16 hrs 12-14 hrs Number of hour for back flow 4-5 hrs 0 hrs 4-6 hrs 7-8 hrs Number of hour for stand water 2-3 hrs 1-2 hrs 1-2 hrs 1-2 hrs

Source: Sub-Institute of Water Resources Planning, 2002 Note: - Amplitude: amplitude of highest daily water level;

- Q (+)max: the highest down flow (flow out toward West sea) - Q(-)max: the highest back flow (flow in from West sea)

- Qbq: average flow rate at measurement period - Tac Thu station on Ong Doc river, about 1km far from Tac Thu-Ong Doc confluence toward Ong Doc rivermouth.

According to the requirement of the detail design For Ca Mau Gas - Power - Fertilizer Complex project, Southern Institute of Water Resources Research had undertaken the measurement of hydraulic regime at 5 stations (Figure 3.3) at Cai Tau confluence including Ong Doc, Trem, Cai Tau rivers and Minh Ha canal in both dry and rainy season: the first period (dry season) lasted from 24th to 29th April, 2002 and the second one (rainy season) lasted from 22nd to 27th July, 2002. The detail assessment report on hydrological regime at the Ca Mau Gas – Power- Fertilizer Complex is presented in 3 specific separated reports. Some results of this survey are summarized in Table 3.9 [5].

Table 3.9 HYDROLOGICAL CHARACTERISTICS IN THE CA MAU GAS-POWER-FERTILIZER COMPLEX IN BOTH DRY AND RAINY SEASONS, 2002

Characteristics Season TV.1 TV.2 TV.3 TV.4 TV.5

I 0.26 0.26 0.25 0.26 0.32 Hmax (m)

II 0.31 0.29 0.29 0.30 0.35 I 0.13 0.15 0.14 0.13 0.17

Hmin (m) II 0.22 0.20 0.19 0.21 0.18 I 0.21 0.20 0.20 0.19 0.25

Hbq (m) II 0.26 0.25 0.23 0.25 0.25 I 0.13 0.11 0.11 0.13 0.15

Amplitude (m) II 0.09 0.09 0.10 0.09 0.17 I 0.12 0.08 0.06 0.13 0.06

Vmax(+) (m/s) II 0.14 0.11 0.18 0.18 0.08 I 0.15 0.16 0.13 0.18 0.10

Vmax(-) (m/s) II 0.12 0.14 0.13 0.15 0.11 I 23.08 8.33 6.46 33.82 3.96

Qmax(+) (m3/s) II 28.48 3.07 19.58 46.35 5.07 I 30.82 17.76 14.25 45.81 5.94

Qmax(-) (m3/s) II 24.68 4.02 14.35 39.95 7.27 I 4.31 1.34 0.88 4.55 0.16

Qbq(+) (m3/s) II 15.39 1.46 10.06 25.49 2.43 I 6.69 2.93 2.21 8.38 1.25

Qbq(-) (m3/s) II 12.44 1.88 8.19 28.49 3.39 I 284.82 164.35 159.27 459.90 130.99

Total volume (m3) II 2.256 0.103 1.327 3.731 0.604 Source: Southern Institute of Water Resource Research, 2002. Notes: TV.1 Trem river - 1,500m far from Cai Tau confluence TV.2 Cai Tau confluence (Period I) and Trai Giam canal (Period II)

TV.3 Cai Tau river - 1,500m far from Cai Tau confluence



TV.4 Ong Đoc river - 1,500m far from Cai Tau confluence TV.5 Minh Ha canal Period I: Hydrological period in dry season (24-29 April, 02)

Period II: Hydrological period in rainy season (22-27 July,02) Q(+)max: the highest down flow; Q(-)max: the highest back flow Convention of flow directions: Flow out to the West sea (+), down flow; Flow in from the West sea (-), back flow

The results from above table show that, the hydraulic regime in the Ca Mau gas-fertilizer-power complex is summarized as follows: - In general, water level of the area has variation though it is not directly affected from the

western of Hau river but due to rainfall, the main source caused flooding in the area and river morphology so the drainage capacity is limited.

- Because of the small oscillation in tidal amplitude, drainage capacity in this area is very limited and difficult, especially when having heavy rains simultaneously with flooding from Hau river caused inundation in large area.

- In the drought months in dry season, the current regime in the rivers depends mainly on tidal currents and the tidal effects from Ong Doc river. However, in the flooding period, besides the direct influence of tidal current, this area is also partly influenced by flood flowing from upstream of the Mekong river. This makes current circulation more complicated and the water velocity decreases. Therefore, the weak dispersion ability and weak transportation of suspended sediment cause alluvia deposition phenomenon in the canal system.

- Based on collected data from many years as well as site measurement results, it can be said that drainage ability in this area is suitable with long lasted ebb-tide, but it has a significant disadvantage with high tidal foot and small amplitude which makes much decrease of drainage capacity. The main drainage direction in Cai Tau confluence is running towards Ong Doc River.

Inundation situation Inundation phenomenon in the area is not only caused by raining but also by tide. The area is usually flooded in rainy season with flooding time lasts from 2 - 3 months (end of August to end of October) with general flooding depth of 0.3 - 0.5m, particularly of over 0.6m in some areas (Figure 3.3a). Besides, low riverside lands of the area are also inundated during spring tidal period of the year (December - January). Existing main hydraulic constructions in the project area [6]

- Along Ong Doc river, from estuary to Tac Thu confluence, there is an embankment with 38.5 km long and 500 m far from river on which is used as a road of 6m wide. High level of embankment is +2.0 to + 2.2m. Below it, there are some small sluices with 1 - 5m in width, from -0.5 to -1.5m in height.

- Along Cai Tau river, there are embankments in both riversides with 6m wide and 1.5-2.2m high.

- Along Trem river, there is embankment in western riverbank with 41km long, 6m wide and +1.5m to +2.2m high, without sluice below. At eastern riverbank, there is embankment with 24km long, 6m wide and + 1.5m to + 2.2m high. Below it, there is sluice with 1.8m wide and 1m high.

- Now, the construction of the Tac Thu sluice and dock and Bien Nhi sluice finished at the end of 2005 and they will be used in March, 2006. The operation of Tac Thu and Bien Nhi sluices can intake the seawater into the aquacultural ponds at the suitable time for shrimp aquacultural activities at some areas along Cai Tau and Trem riverbanks. Besides, they can also supply freshwater to prevent forest fire and to produce double rice crops.



Proposed operation of Tac Thu sluice Tac Thu sluice will be closed to the end of January for keeping freshwater. In December and January, freshwater will be pumped up and stored in order to supply water for trees and forest fire-fighting in the dry season. In February, after pumping enough water for forest-storage and other demands, Tac Thu and Bien Nhi sluices are operated to take seawater for shrimp aquacultural activities until the end of May. The sluice will be opened to get seawater at spring tide and will be closed at ebb-tide. The purpose is to reduce of expenditure of pumping seawater for shrimp aquacultural activities. The operation (open/close) of the sluice depends on the shrimp's growing periods. When the period of producing shrimps finishes (from June to October), the sluice will be operated one-way in order to prevent salinity intrusion, drainage acid water (alum water) and flood water. So, the shrimp aquacultural areas will be changed to growing rice. 3.2.3.2 Water quality Basing on the options of wastewater and cooling water discharge in CM1 & CM2 power plants, RDCPSE had conducted the measurement and analysis of water quality at 4 sites in Cai Tau and Ong Doc river systems (downstream of Tac Thu dock) in December, 2005 (Figure 3.2). The measured and analysed results are shown in Table 3.10.

Table 3.10 PHYSIO-CHEMICAL PARAMETERS OF SURFACE WATER AT CA MAU

POWER PLANT IN 2005

Site pH T0C EC (mS/cm) Salinity (‰) DO (mg/l)

RW-1.1 6.95 25.7 15.3 8.6 5.87 RW-1.2 6.93 27.3 15.2 8.4 6.20 RW-2.1 7.12 23.6 15.6 8.7 5.90 RW-2.2 7.10 26.4 19.6 11.1 5.90 RW-3.1 7.15 26.5 21.8 12.7 4.85 RW-3.2 7.25 28.1 19.9 11.3 6.10 RW-4.1 7.21 26.8 22.1 12.7 4.68 RW-4.2 7.21 27.0 21.1 12.2 5.70

Average-in dry season – 5/2002 7.53 31.8 50.2 31.5 7.08

Average-in rainy season – 7/2002 4.07 31.6 10.3 5.7 7.43

TCVN 5942-1995 5.5-9 - - - ≥ 2

Source: RDCPSE, 2005 Notes:

- RW 1.1: Cai Tau river, discharge site is 1.5-2 km upstream far from power plant at high tide; and RW 1.2 at ebb-tide.

- RW 2.1: Cai Tau river (where to take cooling-water for both power plants): high-tide; RW 2.2: ebb-tide. - RW 3.1: Ong Doc River (500m downstream far from Tac Thu dock): high-tide; RW 3.2: ebb-tide. - RW 4.1: Ong Doc river (1000m downstream far from Tac Thu dock): high-tide, RW 4.2: ebb-tide.

To compare with analytical results on Cai Tau and Ong Doc rivers in 2002 and 2005, it is summarized as follows:

- Because the rainy season in 2005 (December, 2005) lasted longer with heavy rainfall, so pH was increased, and the salinity was distinctly lower in 2005 in comparison with average one measured in dry season of 2002;

- The river's temperature in 2005 (23.6 - 28.1oC) was lower than in 2002 (31.6 - 31.8oC).

The analytical results on chemical components of the surface water quality at the project area in December 2005 are given in Table 3.11.



Table 3.11 ANALYSED RESULTS OF CHEMICAL PARAMETERS OF SURFACE WATER

Site Parameters (mg/l) Phenol

(μg/l) DTS TSS Total N

Total P NH4

+ NO3- NO2

- SO42- BOD5

RW - 1.1 <5 0.062 84.29 3.587 0.025 0.723 0.190 0.072 1378.42 3.28 RW – 1.2 <5 0.067 40.00 3.259 0.022 0.508 0.237 0.071 1349.09 3.47 RW – 2.1 <5 0.072 42.06 2.762 0.033 0.664 0.190 0.112 792.83 2.93 RW – 2.2 <5 0.071 46.00 3.205 0.042 0.508 0.172 0.144 996.17 1.56 RW – 3.1 <5 0.070 53.12 3.244 0.083 0.773 0.175 0.074 977.60 2.77 RW – 3.2 <5 0.066 78.37 2.604 0.064 0.561 0.182 0.090 990.31 2.44 RW – 4.1 <5 0.067 43.33 2.766 0.080 0.724 0.180 0.071 1148.68 3.55 RW – 4.2 <5 0.057 41.88 2.516 0055 0.753 0.193 0.062 1196.58 2.37

Average 2002 <5 0.026 - 1.50 0.083 0.56 0.07 0.05 3400 3.30 TCVN 5942-

1995 20 0.3 - - 1 15 0.05 - <25

Source: RDCPSE, 2005 Notes: - RW 1.1: Cai Tau River, the cooling water discharge position is 1.5 -2 km upstream far from the Power Plant :

high-tide; RW 1.2: ebb-tide. - RW 2.1: Cai Tau river (where to take cooling- water for both Power Plants): high-tide, RW 2.2: ebb-tide. - RW 3.1: Ong Doc river (500 m downstream far from the Tac Thu dock): high-tide; RW 3.2: ebb-tide. - RW 4.1: Ong Doc river (1000 m downstream far from Tac Thu dock): high-tide; RW 4.2: ebb-tide. Comparison the baseline survey results in 2002 and 2005 in all sampling sites with Vietnamese Standard TCVN 5942 - 1995, show as follows: - The total oil content (DTS), total N, NH4

+, NO3-, NO2

- in 2005 is higher than in 2002 but still lower than allowable limits.

- Especially, at station R2 , NO2- concentration was exceeded the allowance standard. It

means that water on Cai Tau river where cooling water intakes has signal for pollution.

Table 3.12 HEAVY METAL CONTENT IN SURFACE WATER (mg/l)

No. Sample Zn Cu Ba Pb Cd Fe Ni Cr Mn Hg As

ppm ppb 1 RW-1.1-KL < 0.005 < 0.005 < 0.25 0.010 < 0.005 3.69 < 0.08 < 0.08 0.65 < 0.001 0.70

2 RW-1.2-KL < 0.005 < 0.005 < 0.25 0.004 < 0.005 2.13 < 0.08 < 0.08 0.59 < 0.001 0.70

3 RW-2.1-KL < 0.005 < 0.005 < 0.25 0.002 < 0.005 1.53 < 0.08 < 0.08 0.33 < 0.001 0.40

4 RW-2.2-KL < 0.005 < 0.005 < 0.25 0.002 < 0.005 1.64 < 0.08 < 0.08 0.31 < 0.001 0.60

5 RW-3.1-KL < 0.005 < 0.005 < 0.25 0.002 < 0.005 1.21 < 0.08 < 0.08 0.24 < 0.001 0.70

6 RW-3.2-KL < 0.005 < 0.005 < 0.25 0.005 < 0.005 1.30 < 0.08 < 0.08 0.23 < 0.001 0.50

7 RW-4.1-KL < 0.005 < 0.005 < 0.25 0.003 < 0.005 2.47 < 0.08 < 0.08 0.27 < 0.001 1.00

8 RW-4.2–KL < 0.005 < 0.005 <0.25 0.002 < 0.005 0.95 < 0.08 < 0.08 0.20 < 0.001 0.70

Average 2002 < 0.005 < 0.005 <0.25 0.001 < 0.005 0.62 < 0.08 < 0.08 0.63 < 0.001 0.87

TCVN 5942-1995 2 1 4 0.1 0.02 2 1 1 0.8 0.002 - Source: RDCPSE, 2005

The analytical result of heavy metal content in surface water at the project area and its vicinity in 2005 shows that: - Most of the metal contents in surface water are below the allowance limit.

- The iron (Fe) content in 2005 is much higher than in 2002 but is still within the allowance limits of TCVN 5942 - 1995 (column B).

3.2.4 Sediment quality

Grain size distribution [4]



The analytical results on grain size of sediment samples at Cai Tau and Ong Doc rivers are shown in the below diagram:

AVE 2002 Sidement Total OM AVE 2002

Source: RDCPSE, 2005 According to the analytical results, the sediments at 4 sampling sites are quite homogenous and fine silt. The comparision with analytical results in 2002 shows that the sediment from the upstream to the confluence of Cai Tau river and Ong Doc river (downstream of Tac Thu dock) is fine silt and has not much variation.

Hydrocarbon content The analytical results of hydrocarbon in sediment in 2005 at 4 sites varied from 77-177 µg/g. Among them, highest value is at station R2, the place to take cooling water for two power plants. The high hydrocarbon content is due to this site locates closely Cai Tau residential area and the river confluence. So, it is received the waste discharges from human activities.

Metals in sediment The analytical results of metal content in sediment on Cai Tau and Ong Doc rivers in 2005 are shown in the table 3.13.

Table 3.13 HEAVY METAL CONTENTS IN SEDIMENT

Cu

Pb

Zn

Cd

Ba

Ni

Cr

Mn

Hg

As

Fe No.

Samples (µg/g) (%)

1 S - 1.1 - KL 30.68 21.44 89.38 < 1 214 29.78 64.86 267 0.32 6.80 4.03 2 S - 1.2 - KL 30.03 20.81 88.90 < 1 196 31.49 61.29 273 0.05 6.30 4.00

3 S - 2.1 - KL 28.94 23.79 101.82 < 1 187 28.31 57.68 190 0.95 5.10 7.07 4 S - 2.2 - KL 27.69 15.18 80.23 < 1 173 24.58 55.65 148 0.08 3.10 8.52 5 S -3.1 - KL 36.93 21.06 108.51 < 1 224 35.13 67.96 330 0.21 5.60 3.45

6 S - 3.2 - KL 31.77 21.67 110.33 < 1 202 34.33 62.32 300 0.07 5.30 3.61

7 S - 4.1 - KL 34.88 20.35 112.26 < 1 185 33.86 57.25 273 0.09 6.60 4.33

8 S - 4.2 - KL 30.88 22.50 97.17 < 1 201 31.42 60.37 465 0.23 6.40 3.26

Average 2002 34 19 91 < 1 190 26 58 320 0.068 16 3.1 Source: RDCPSE - 2005 The above results show that the iron (Fe) content is high on Cai Tau river (where to take cooling water). This can be due to washing out of acid sulfate soil process. The acid sulfate soil contains a lot of pyrites (FeS2) which causes increasing iron ion in river bottom sediment.

11783

1.5

707977

TB 2002 = 128

AVE 2002 = 29.2

0

50

100

150

R1 R2 R3 R4 ? 1 ? 2

Station

Tota

l OM

(mic

rogr

am/g

ram

) Formatted: Font: Bold

Formatted: Font: 10 pt



However, to compare with the analytical results in the dry season on Cai Tau river (N3), in 2002, the iron content in sediment obviously increases in the rainy season in 2005. Other parameters such as Ba, Mn, etc. in the rainy season of 2005 are higher than in 2002; but Hg and Cd are still low. 3.2.5 Hydrogeology and groundwater quality Refer to the document of "Existing investigation, evaluation and forecasting variation of groundwater capacity, quality and exploitation planning in Ca Mau province" shows that hydrogeology in Ca Mau can be divided into 6 main aquifer strata as below [7]:

Stratum 1 – Holocene aquifer stratum (QIV): distributes in the whole province, two per three (2/3) area is often submerged. The bottom depth is from 30 to 42 m. The composition mainly consists of clay silt, sand, fine sand clay, humus, having ash-grey, brown-grey colour with the thickness of 30 - 50 m. Groundwater is completely brackish water due to the interaction with the river/ canal surface water (affected by tide). Characteristic of this aquifer is hard water, pH = 7.7-8.3, carbonic corrosion and nitrite pollution (NO2

- = 0.53-21 mg/l).

Stratum 2 - middle Pleistocene - late aquifer stratum (QII-III): is located under QIV layer and covers in the whole province. Depth of the bottom layer is in the range of 98-136m. The isolated layer with QIV stratum is clay and mixing clay; the below is gravel sand layer containing water. Water in this layer is generally fresh water.

Stratum 3 - early Pleistocene (QI) aquifer stratum: is located under the QII-III layer and cover in the whole province. Depth of the bottom layer is 160-200m. The isolated layer with QII-III stratum is the clay and mixing clay; the below is gravel sand layer containing water. At the present, water in this aquifer is generally fresh, soft and contaminated by nitrite, nitrate. It is possible to get brackish water at the depth of 170m (Tan An Dong village).

Stratum 4 - Pliocene aquifer stratum (N2): located under QI stratum and extend to the whole province. Water in this layer is generally fresh, soft and contaminated by nitrite, nitrate and a lot of residue.

Stratum 5 - N13: this stratum is located under N2

1 stratum and not covered in the whole province.

Stratum 6: fissure water in base stones before Kainozoi period: it is exposed at the Hon Khoai, Hon Chuoi islets, At Nam Can Town, fissure water can be found at 372m depth (granite).

The analytical results of ground-water quality at a drilling-well at Power Plant 2 in 2005 and the comparison with the analytical results of groundwater in 2002 in this area [5] are shown in the table 3.14.

Table 3.14 ANALYTICAL RESULTS OF GROUNDWATER QUALITY AT THE PROJECT AREA



Parameters Results in 12/2005

Average results in 2002

TCVN 5944:1995

pH 7.55 7.36 6.5 - 8.5 Temperature (0C) 30 - - Conductivity (mS/cm) 1.48 0.85 - Salinity (‰) 0.8 0.5 - Hardness (mg CaCO3/l) 200.5 153 300 - 500 TDS (mg/l) 540 371 - Cl- (mg/l) 109.9 87 200 - 600 TSS (mg/l) 2.67 49 750 - 1500 NO3

- (mg/l) 0.016 0.243 45 NO2

- (mg/l) 0.002 0.078 - SO4

-2 (mg/l) 0.49 2.3 200 Phenol (μg/l) <5 <5 1 Feacal coliform (MPN/100ml) 8 140 - Coliform (MPN/100ml) 23 4593 3

Source: RDCPSE - 2005

Table 3.15 RESULTS OF HEAVY METAL CONTENTS IN GROUNDWATER AT THE PROJECT AREA

Parameters

Zn

Cu

Ba

Pb

Cd

Fe Ni Cr

Mn

Hg

ppm

As ppb

2005 < 0.005 < 0.005 < 0.25 < 0.001 < 0.005 0.57 < 0.08 < 0.08 < 0.03 < 0.001 <0.20

Average 2002 0.098 < 0.005 < 0.25 < 0.001 < 0.005 1.01 < 0.08 < 0.08 < 0.03 < 0.001 <0.20

TCVN 5944-1995 (mg/l) 5 1.0 - 0.05 0.01 1-5 - 0.05 0.1-0.5 0.001 0.05

Source: RDCPSE - 2005 The analytical result of groundwater quality at the project area in 2002 and in 2005 shows that all of the water quality parameters are below the allowance limits of Vietnamese Standards TCVN 5944-1995, except the Coliform. 3.2.6 Characteristics of Topography and Geology [7]

Topography Ca Mau is annual alluvial deposit ground and in general, the geographical structure is weak. Topography in Ca Mau is divided into five zones of ecological topography as follows:

1. Topography of triangular delta sediment: Ca Mau City is ecological region with the highest altitude. Average elevation of Ca Mau City is from 0.9-1.3m and the elevation of the surrounding fields is about 0.5-0.7m (the altitude system of Mui Nai Cape, Ha Tien).

2. Topography of alluvial deposit cape: it includes almost districts belonging to the province such as Ngoc Hien, Dam Doi, Cai Nuoc, U Minh, Tran Van Thoi and one part of Ca Mau City. The region is covered by mangrove absolutely affected by tidal regime with a lot of complex water transition areas, high rainfall; therefore, aquatic-forest products are abundant and a place of the special one rice-crop.

3. Topography of Hollow rain water submerged region: the typical region is in Thoi Binh, U Minh districts. This is covered by Melaleuca forest on low area and due to high rainfall here, it is difficult to drain.

4. Topography of central suspended edge region: It is located in Thoi Binh district and is a sub-region with favourable soil condition, high rainfall, rare submergence.



5. Topography of central hollow at Co estuary: belonging to U Minh, Thoi Binh districts. This area is submerged and salinity and acid sulphate contaminated.

Geology

Based on the geological survey report at Ca Mau Gas-Power-Fertilizer Complex undertaken by Power Engineering Consulting Company No.2 in October, 2003, the total 6 soil layers and 2 sub-layers are identified as follows:

- Layer 1: melt clay silt with average thickness of 16 m, low intensity of cutting and compressive resistance, high sensitivity;

- Layer 2: Flexible hard clay to semi-hard with relative high intensity of cutting and compressive resistance, but thin thickness (lower than 11 m).

- Layer 3: Flexible soft clay to flexible hard clay containing humus and poor homogenous.

- Layer 4: sandy clay alternating clay layers with intensity of high cutting and compressive resistance, but thin thickness (average 3.6 m) and poor homogenous.

- Layer 5: semi-hard clay alternating fine sand layer at the depth of 40-45 m. Although intensity of cutting and compressive resistance is at mean level but the result of horizontal compressive resistance shows that compressive module and the thickness are very high (more than 30 m).

- Layer 6 and sub-layer 5a: these layers have rather high intensity of cutting and compressive resistance, higher than upper layers.

Analysis result of each soil layer shows that the depth foundation solution is suitable. The 5.5a and 6 layers may be made as base for pile foundation feet. For works having small concentrative loading capacity, piles may be driven through thick and soft layer 1, thin clay layer 2 and inhomogeneous layers 3 & 4. The analytical result of metal content in soil samples at the project area in 2005 [4] is given in Table 3.16.

Table 3.16 ANALYTICAL RESULT OF METAL CONTENT IN SOIL SAMPLES (µg/g)

Samples Cu Pb Zn Cd Ba Ni Cr Mn Hg As Fe (%)

S - Đ1.1 - KL 27.38 16.05 74.65 < 1 186 26.50 63.73 297 0.05 5.20 3.06

S - Đ1.2 - KL 30.41 22.21 76.60 < 1 203 28.57 70.10 280 0.12 6.20 3.29

S - Đ2.1 - KL 19.12 18.25 48.96 < 1 308 15.66 35.39 269 0.03 6.80 2.14

S - Đ2.2 - KL 17.69 19.77 45.09 < 1 265 14.24 29.60 257 0.03 4.70 1.76

TCVN 7209:2002 (*) 100 300 300 10 - - - - - 12 -

Source: RDCPSE, 2005. Notes: Đ1: closed to Power Plant 1

Đ2: gate of Power Plant 2 TCVN 7209:2002 (*): Maximum limits of total As, Cd, Pb, and Zn - applied for industrial land.

The analytical result of metal content at the CM2 power plant (in the proposed area of Fertilizer Plant) in two years (2002 & 2005) shows that the contents of Arsenic (As), Cadimi (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) are much lower than the Vietnamese Standards TCVN 7209:2002 which are applied for industrial land. 3.2.7 Seismic, earthquake and erosion situation



Seismic and earthquake The project area is not situated in pronounced earthquake epicenter area. According to MSK scale, the earthquake intensity of 6 for the Ca Mau area is confirmed equivalent to ground surface acceleration basic coefficient of 0.05 g.

Erosion Refer to the Report "Study on the shoreline erosion and variation along Southwest coastal area from Ca Mau cape to Cambodian border" [8] undertaken by Ho Chi Minh City Physics Sub-institute and the Report "Existing of riverside erosion in Ca Mau Province" prepared by DoSTE of Ca Mau [9] show that the eroded areas often concentrate at the following areas:

• The coastal zone: the Eastern coastline was eroded much stronger than the Western coastline. Toward to the western sea, in the coastal area of Thailand gulf belonging to U Minh, Tran Van Thoi districts during 1992 - 2001 was eroded about 100-335m. In addition, the coastal zone, from Ganh Hao estuary to Ho Gui River mouth (Dam Doi district), was strongly eroded with the rate of more than 10m/year.

• The riverside area: there are 3 strong eroded areas (erosion rate is more than 10 m/year) such as: Tan Tien market (Dam Doi district), Nam Can townlet, Nam Can port, Cai Nai hamlet (Ngoc Hien district), Ca Nay market (Ngoc Hien district). The result shows that the eroded areas often occur at the bendy sections, the river-confluence with the high tide amplitude and crowded inhabitants, constructive works and high density of boats anchoring at large flow rivers.

• In addition, at present, the usual and important eroded routes have high density of boats such as: Bay Hap river from Ca Mau to Dam Cung, Ong Doc river from Ca Mau city to Ong Doc river mouth. The main reason is due to waves generating from waterway transport means (mainly is heavy loading and high-speed ships)

Period of erosion occurrences are often in three months from May to August, especially in May and June. This period coincides with the duration of lowest tidal peak corresponding to the lowest average water level on the rivers/canals and also in the beginning of the rainy season. Most erosion cases happened in heavy rains, at the lowest ebb-tide and at night time. 3.3 BIOLOGICAL CHARACTERISTICS 3.3.1 Terrestrial ecosystem Flora system

Based on the vegetation field surveys in 2002, 2003 and 2005 conducted by RDCPSE, there are two main flora groups in the project area and its vicinity as follows: semi-natural melaleuca forest, planting melaleuca forest and seasonal flooded grassland and crop plants. At Ca Mau Gas-Power-Fertilizer Complex, vegetation is mainly rice-field, Eleocharis grassland, hodgepodge plants, Melaleuca, Eucalyptus, coconut, Melastoma, Annona... In the vicinity, Vo Doi specific forest is located 8.5 km far from the project area with following characteristics: ♦ The structure of semi-natural melaleuca forest is separated to 2 distinguished layers.

The wooden tree layer consists of melaleuca with density of 1 - 2 trees/m2. Other wooden trees are available with small quantity such as Ilex simosa and Alstonia spathulata. Regional liana ecosystem is especially well growth with Stenochlaena palustris, Flagellaria indica, Sumatra Scleria sumatrensis and Dioscorea glabra. On the



banks along the forest boundary, Stenochlaena palustris and Sumatra make thick brushes with the presence of Cayratia trifolia, Ageratum conyzoides, Thespis divaricata, Vigna luteola and Hygrophila salicifolia.

− The planted melaleuca forest depending on varied ages distributes almost half of eastern

region. In mature forest, it is often thinly and exists well growth vegetation closing on the ground. In addition, there are still grassplots with the natural regeneration of young melaleuca.

− The grassplot community is predominant with Eleocharis dulcis, in addition, there are some grass plants exist: Cyperus halpan, Cyperus polystachyos, Fuirena umbellata, Philidrum lanuginosum and Phragmites vallatoria. There are occasionally Cyperus elatus and Cyperus digitatus mingling with Eleocharis grassplot and Phragmites. On the upper layer, Phragmites vallatoria is predominant. Moreover, there are other popular plants such as: Cayratia trifolia, Vigna luteola, Panicum repens and Melastoma affine. Phragmites vallatoria forms thick brush layer of 3m high.

− The internal canals in Vo Doi special-use melaleuca forest have a diversity floral community with floating and submerged species like water-hyacinth (Eichornia crassipes), Pistia stratiotes, Salvinia cucullata, Ipomoea aquatica, Azolla pinnata, Spirodela polyrrhiza, Lemna aequinoxialis and rare wolffia is acute water-fern Lemna tenera (Tran Triet pers.comm).

− Agriculture plants: the major agriculture plant is rice combined with forest planting and some other fruit trees such as: banana, papaya, coconut, etc. and other farm products. Moreover, Ca Mau province has planned 215 ha sugar cane at Thoi Binh and U Minh districts consisted of 127ha along Trem River, 88 ha at Khanh An resettlement area [10].

Fauna

U Minh melaleuca forest is a favourable habitat for a lot of animals. At the beginning of the rainy season, fish from rivers swimming into rice-fields and canals in malaleuca forest for breeding and growing. Flooding water brings more alluvial and organic matter accompanied with decayed compositions in the melaleuca forest to form a rich food source for plankton and fresh-water small fish and shrimp. These organisms feed on carnivorous fish such as; snake-head (Ophiocephalus striatus), Ophiocephalus micropeltes, Ophiocephalus lucius, to make them growing well. Prawn, fish, amphibians are also a food source of otter, water-snakes (Enhydric enhydris, Homalopsis buccata, Enhydris bocourti and green dendrophis Trimeresurus popeorum). The abundance of shrimps and fish in the melaleuca forest has attracted a lot of birds for feeding such as: stork, heron, night heron, ibis, Phalacrocorax niger, Galinular chloropus. In addition, there is also the presence of Ibis leucocephalus, Xenorynchus asiaticus. Cionia episcopus, Pelecanus philippensis, Leptoptilos dubius. Besides, there are insectivorous birds such as: Merops viridis, Lonchura punctulata, Ploceus philippensis burmanicus, Passer montanus, Fringilla montifrigilla. Additionally, seasonal inundated condition has created favourable habitat for deer, wild pig, weasel, wildcat, varan, pangolin, python. On the melaleuca branch, there are bats, monkeys, squirrels, etc. (Phung Trung Ngan, 1987). Insects in the melaleuca forest are rather abundant including 45 species belonging to 7 orders, in which bee species is dominant with honey-bee, wasp ... (Phung Trung Ngan, 1987). According to previous surveys, at Vo Doi special-use forest, Tran Van Thoi, U Minh III forestry farms, there are 12 amphibian species, 32 reptilian species, 100 species of birds, 18 mammalian species. Up to now, animals in melaleuca forest are reducing considerable.



Tiger, panther, deer... cannot be found, the valuable rare birds are also reducing, the remained amount remains not much [10]. The latest surveys of Birdlife Vietnam (2000) had recorded 82 bird species at Vo Doi special-use forest, Tran Van Thoi, U Minh III forestry farms, where the quantity of bird species is the third grade in comparison with other wetlands in the region. Birds are really abundant with Chinese little bittern (Ixobrychus sinesis), Bronze-winged Jacana (Metopidius indicus) and warbler (Porphyrio porphyrio). However, there are no recorded "threaten species" in this area. According to Vo Doi forestry officers, woolly-necked stork (Cionia episcopus) is often observed at the buffering zone. The environmental disturbance and destruction, especially forest fire, are reasons caused disappearance of big water birds [9]. Forestry birds such as: scarlet minivet (Pericrocotus brevirostris) and indochinese cuckoo shrike (Coracina polioptera) are found in mature forest. Besides, red squirrels (Calloscirius sp.) are often observed along the canal banks. Large flying fox (Pteropus sp.) used to be famous before, they lived concentrated in a large area at Vo Doi, but there are few at present. On the field survey along the gas pipeline conducted by RDCPSE within 3 – 7th January, 2003, a flock of bats flying from Vo Doi special-use forest to U Minh III forest was observed. 3.3.2 Aquatic ecosystem Phytoplankton [4]

The analytical results of phytoplankton in 2005 at the project area are summarized in the Table 3.17.

Table 3.17 THE ANALYTICAL RESULTS OF PHYTOPLANKTON AT THE PROJECT AREA

Number of species (/site(0,04m3)

Density (x1000 TB/m3)

Phylum

R1 R2 R3 R4 R1 R2 R3 R4 Bacillariophyta 19 12 22 25 842 460 1380 1148 Chlorophyta 1 1 0 1 20 16 0 14 Chrysophyta 0 1 0 0 0 4 0 0 Cyanophyta 3 2 2 6 396 184 1040 875 Dinophyta 1 0 1 1 14 0 28 11 Euglenophyta 6 2 2 1 66 20 28 4 Total 30 18 27 34 1,338 684 2,476 2,051 Diversity (Hs) 3.21 3.26 2.71 3.60

Source: RDCPSE-2005 Notes: R1: Cai Tau river, at cooling water discharge site, upstream of the plant

R2: Cai Tau river, cooling water intake site R3: Ong Doc river, 500m downstream far from Tac Thu dock R4: Ong Doc river, 1000m downstream far from Tac Thu dock.

The above result shows that:

- There are about 18-24 species found at 4 surveyed sites in 2005.



- The founded species belong to 6 different algal phyla: Bacillariophyta, Cyanophyta, Euglenophyta, Chlorophyta, Dinophyta and Chrysophyta. Bacillariophyta is most dominant, occupying 71.6% total recorded species. Next are Cyanophyta, Euglenophyta, Chlorophyta, Dinophyta and Chrysophyta.

- Although density of phytoplankton in Cai Tau river (R1&R2) is lower than the one in Ong Doc river (R3&R4), the number of species is quite equal in both rivers. With the high number of species and density, the typical diversity parameters of community varied not much among the sites. Particularly, at R3 site, the diversity is low due to high density but low number of species. This is because the R3 site located on Ong Doc river, downstream of Tac Thu dock where there are a lot of fishery aquaculture activities. So at this site, the water is turbid because of discharged water from aquacultural ponds (the TSS equals 66, higher than three other sites). The development of phytoplankton community depends on the light. At the R2 site, the number of species and the density of community decrease significantly while the diversity is still high. This site is located next to Cai Tau residential area so, it is polluted by organic matters (the NO2

- in the surface water is 0.13 mg/l, exceed the permitted limits 0.05 mg/l - TCVN).

Zooplankton The analytical parameters of zooplankton in 2005 [4] at the project area are shown in the Table 3.18.

Table 3.18 THE ANALYTICAL RESULTS OF ZOOPLANKTON AT THE PROJECT AREA

Number of species (/ site( #5m3)

Density (individual /m3)

Group

R1 R2 R3 R4 R1 R2 R3 R4 Amphipoda 0 0 1 1 0 0 1 1.3 Chaetognata 3 2 3 3 6.7 1.6 1.9 4.0 Cladocera 1 1 0 1 6.7 1.6 - 2.0 Copepoda 5 7 11 14 326.2 979.2 614 1229 Decapoda 2 1 2 1 6.5 1.1 2.2 3.1 Larvae 4296.8 514.6 432.3 714.5 Medusae 3.8 3.2 4.1 5.1 Total 11 11 17 20 4646.8 1501.2 1055.6 1959.1 Diversity (Hs) 1.65 0.67 1.65 1.92 Source: RDCPSE, 2005 Above analytical results show that the diversity is lowest at the R2 site on Cai Tau river where is planned for taking cooling water, because this area is polluted. It is clearly to identify in the above analytical results (the NO2

- is higher than allowable limit).

Benthos [4] The analytical results of benthos in December, 2005 are shown in Table 3.19.

Table 3.19 ANALYTICAL RESULTS OF BENTHOS AT THE PROJECT AREA

Number of species Density (individual /m2)



(/ site( 0,15m2) Group R1 R2 R3 R4 R1 R2 R3 R4

Crustacea 1 0 2 2 27 0 20 13 Polychaeta 0 0 2 3 0 0 87 167 Total 1 0 4 5 27 0 107 180 Diversity (Hs) 0 0 1.65 1.34

Source: RDCPSE, 2005 The above analytical result of benthos shows that at R1&R2 sites on Cai Tau River, the benthic community is very poor. Especially, at the R2 site, where is planned to intake the cooling water, the benthic community disappeared completely. The sediment of this area (R2) has the high content of hydrocarbon. This may be this area is affected by the wastewater from the residential area and Ngoc Sinh Fishery Processing Factory on canal 21. Aquacultural resources

According to the result from meeting between RDCPSE and Ca Mau Fishery Department (June, 2002 and January, 2003), the aquacultural resource at canals/ rivers around the project area (Ong Doc river, Trem river and Cai Tau river) is insignificant because of the poor aquatic communities. As for Vo Doi specific forest, freshwater fish and shrimp are rather abundant owing to the decayed cover in the melaleuca forest is a rich food source for aquatic species. 3.3.3 Natural Ecological Conservations at the project area and the vicinity At the Ca Mau Gas-Power-Fertilizer Complex, there is no any bird sanctuary or ecological conservation area. However, in the radius of 10km, there is Vo Doi specific forest about 8.5-9 km far from the project area. Total area of Vo Doi specific forest (9o15'N, 104o55'E) is about 3,724 ha belonging to U Minh Ha, Ca Mau province. This is the remained oldest melaleuca forest. Flora is mainly Melaleuca cajuputi, Phramites karka, Saccharum arundinaceum... Animals are rather abundant such as: wild pig (Sus scrofa), deer (Cervus unicolor), weasel, squirrel, python, snake, turtle and other wild animals. 3.4 SOCIO-ECONOMIC CONDITION 3.4.1 Population [11] Population of Khanh An commune accounting to 2005 was about 18,000 (Khanh An People's Committee) consisting of mainly Kinh, Khmer and Chinese. Due to topography condition, production activities and infrastructure, Ca Mau inhabitants concentrate at the town, townlet, river confluence and along the canal banks. At the project area, inhabitants concentrate at Cai Tau residential area (opposite to Gas-Power-Fertilizer Complex). Since 2001, inhabitants in the Gas-Power-Fertilizer Complex (hamlets 1, 3 and 6) had to move to temporary resettlement area belonging to the K1 Cai Tau Prison area. Integrated situation of population and labor distribution at hamlets 1, 3 and 6 is given in Table 3.20.

Table 3.20 POPULATION AND LABOUR DISTRIBUTION AT HAMLETS 1, 3 AND 6

No. Population situation Hamlet 1 Hamlet 3 Hamlet 6



No. Population situation Hamlet 1 Hamlet 3 Hamlet 6 1 Number of people 1548 458 1156 2 Number of people at labor-age 1049 281 694 3 Total household 291 81 256 4 Agriculture-forestry-fishing household 260 79 214 5 Industry-construction household 5 - 3 6 Service household 11 - 34 7 Other service activities 13 2 5

Source: People Committee of Khanh An village, U Minh District, 2001 3.4.2 Administrative boundary and future planning orientation The Ca Mau Gas-Power-Fertilizer Complex is located at Khanh An commune, U Minh district. Khanh An natural area is 5,065 ha, in which productive land area are 3,352 ha. Khanh An commune has 10 hamlets ordered from 1 to 10. The power and fertilizer plants are located at hamlets 1,3 and 6 next to residential area of hamlet 4. According to information of Ca Mau Construction Department in December, 2005, the scheme orientations of Khanh An commune are mainly Khanh An residential area, traffic systems and Ca Mau Industrial Gas-Power-Fertilizer Complex. In present, Ca Mau province has constructed road of 14 km length from Ca Mau city to Ca Mau Industrial Gas-Power-Fertilizer Complex. The new resettlement area is 1,080 ha that is planned to build at U Minh III farm-land far away from the project area (Figure 3.4). This new resettlement area is divided into 918 separately portions for households with the model of city house, garden house, agricultural land, school, entertainment area, etc. In fact, this area is still wild land where has not yet construction activities. In general, Ca Mau is undeveloped industrial province. So, the Ca Mau Gas-Power-Fertilizer complex is the first and the largest heavy industrial area in the province's development planning orientation from 2001 to 2010. 3.4.3 Agricultural activities At the project area, yield of rice is very low (25-30 bushels/0.1 ha) where there are only double rice crops. At the present time, due to taking sea water for aquaculture, there is only one crop of autumn-summer). The spring-winter crop is changed to shrimp cultivation. At present, one rice-crop and one shrimp-crop pattern is enlarging quickly, and the area of rice cultivation curtails gradually. Since 2001, most of the rice area along Cai Tau river and Minh Ha canal had changed to ecological shrimp development. Accounting to 2005, total shrimp-crop area of Khanh An commune is 2,846 ha and the shrimp cultivated area is 557 ha. There are 1,384 households feeding shrimps alternating with sea-perch, pointed-tailed goby (Pseudapocryptes elongates), crab, etc. The area for double rice crops in the province remains only 116 ha [11]. The area of fruit-trees, vegetables and crops highly increases because many households used their house's pond edge and their boundary for cultivating. Due to the price of sugar-cane in 2005 is higher than in the former years, household's difficulty is reduced by the profit from sugar-cane. Because of the bird flu at the beginning of 2005, a large number of infected poultries were destroyed. This makes the proposed plan uncompleted.



Achievements in 2005 of the people in Khanh An commune are as follows [11]:

- The area of autumn-summer crop occupied 116 ha which concentrates at hamlet 6, 7 and 8. The harvest was completed in September, 2005 with productivity of 6 tons/ ha.

- The area of shrimp aquaculture occupied 2,846 ha. The plan of 2005 was completed. The average productivity is 60-80 kg/ha. The estimated productivity is 227 tons, equivalent with 70% of the plan.

- There are 21 households with model of 30 millions/ha/year production and 6 households with shrimp-rice-fish model.

- The organisation of producing at the resettlement area has not yet carried out, but the main remaining matters of land in the commune area were solved.

- About the bird flu epidemic, two inoculations were conducted against the epidemic for 7,847 poultries, gaining 100% compared with the surveyed data. The protection and prevention plan of bird-flu disease is available for the next period.

3.4.4 Industrial production activities Ca Mau Gas-Power-Fertilizer complex is the biggest high technical industrial zone of Ca Mau province that is constructed in Khanh An commune. It includes power plant, fertilizer plant, gas distribution station and PM3 - Ca Mau gas pipeline system. In 2005, a processing fishery factory named Ngoc Sinh has operated in the commune. 3.4.5 Infrastructure and transportation 3.4.5.1 Infrastructure Power supply

At present, the average quantity of electricity is 100 kwh/person.year, equivalent with 30% the national level. It is estimated that electric capacity demand of Ca Mau province in 2005 is about 59 MW and the 110kV stations of Ca Mau province will be supplied by 220 kV stations arrived from Bac Lieu province in 2010 in order to supply stable electricity for Ca Mau. Besides, in order to synchronize with the gas turbine thermo-electricity plant, a 220 kV station will be built in Ca Mau in the period 2006 - 2010. A transformer station at hamlet 10 was built by Management Board of the Southern grid A, Khanh An commune with the power from 220 kW to 110 kW which is supplied for province's activities. The area of transformer station is about 31,000 m2. Ca Mau Power Department had completed pulling the low voltage power wire (1000m) from T13 sluice to the new canal at hamlet 10 which is supplied for inhabitants of this area (over 25 households). Telecommunication

At present, Vinaphone, Mobiphone and Viettel waves are available at the project area. At Khanh An, there are 483 telephones with average of 3.5 telephones/100 persons. The telecommunication system serves well and provides much more information for commune people [11]. Water supply



At present, Ca Mau Water Supply Company is studying for enlarging and upgrading the water supply system of Ca Mau city. It is estimated that output capacity is 35,000 m3/day (15,000 m3/day at present) from ODA fund of Italian government and contribute capital. 3.4.5.2 Transportation Road transportation

Before 2002, it seems to have no road transportation system from Ca Mau city to Khanh An commune and waterway transportation is the main mean of the local people in this region. However, since the site clearance and local people removal for Ca Mau gas-power-fertilizer complex project (2001) is implemented, the People Committee of Ca Mau province has carried out to construct a road of 6m in width along Minh Ha canal, connecting from Ca Mau to U Minh district. In addition, Petrovietnam has cooperated with Ca Mau province to build a new road of 14.5 km length from Ca Mau city to gas-power-fertilizer complex at Khanh An. This project was approved in October 10th, 2005 and named "transportation system from Ca Mau city to gas-power-fertilizer complex". The beginning of construction was announced in December 10th, 2005 and it is planned to complete in 14 months. Waterway transportation [12]

Ca Mau has closed waterway system that is quite convenient for inter-provincial, inter-district and internal transportations. However, during the exploitation, many banks along rivers and canals have been eroded. Following are main internal waterway routes passing through project area:

Ca Mau city - Ong Doc river: 40 km length Ca Mau city - Ganh Hao - Bay Hap: 31.5 km length Ca Mau city - Dam Doi - Tam Giang - Nam Can: 71 km length Ca Mau city - Cai Tau - Tieu Dua: 51 km length

Diagram of main waterway systems from the project area to the nearby provinces is shown in Figure 3.5. At Khanh An commune, ferry boats arriving and leaving Khanh An commune are very crowded. The number of boats passing Cai Tau confluence is given in Table 3.21 [13]

Table 3.21 THE DAILY NUMBER OF PASSENGER BOATS IN CAI TAU CONFLUENCE - KHANH AN VILLAGE COMMUNE

No.

Waterway route Quantity of return boat /day (boat)

Passengers/boat (passenger)

1 Ca Mau – U Minh 30 25 2 Ca Mau – Thoi Binh 30 25 3 Ca Mau – Thoi Binh 2 35 4 Ca Mau – Thoi Binh 2 45 5 Transport boat – other boats 40 -

Source: Management office of Wharf A, Ward I, Ca Mau city (2002) 3.4.6 Aquaculture



According to statistical data of Ca Mau Fishery Department in 2005, the area and the yield of fishery and shrimp aquaculture in U Minh district from 2000 to 2005 are shown in Table 3.22.

Table 3.22 AREA AND YIELD OF FISHERY AQUACULTURE IN U MINH DISTRICT

Parameter Unit 2000 2001 2002 2003 2004 2005 Surface-water area for fishery aquaculture

ha

15,524

23,271

22,458

22,628

22,203

22,200

Surface-water area for shrimp aquaculture

ha

2,294

9,410

12,235

11,791

10,955

11,360

Yield of fishery aquaculture

ton 15,496 12,885 4,228 4,604 5,612 6,546

Yield of breeding fish ton 15,300 11,692 2,129 2,256 3,500 3,910 Yield of breeding shrimps ton 196 1,193 2,100 2,348 2,112 2,636

Source: Ca Mau Fishery Department, 2005 The above statistical data shows that the conversion into fishery aquaculture structure most popular occurred in 2001 & 2002. However, in 2005, the surface-water area for fishery and shrimp aquaculture was reduced. Project area is located in freshen-water zone, it is not the key aquacultural development area of the Ca Mau province. The aquaculture area from Ong Doc estuary to Khanh An commune (project area) is about 25,000 ha, occupying 10% in the total area of the commune [Ca Mau Fishery Department]. Since 2001, Khanh An village has implemented agricultural structure changes from double rice crops to one shrimp and one rice crops in large area. This got supports from local people. Until now, the progress of structural conversion is quite fast and the economic effect is quite good. To 2001, there are 2,391ha converted in the whole village, occupying 71.33% in the total cultivated area of the commune. The productivity of shrimp farming in 2001 was 430.38 tons and the average productivity was 180 kg/ha/year. According to the report of Ca Mau Fishery Department in 2005, in Khanh An commune the aquacultural yield is not high, estimated only about 60-80 kg/ha in 2,800 ha of cultivated area. 3.4.7 Health and Education [11] Health: At Khanh An commune, there are one medical station with 1 doctor, 3

physicians, 1 pharmacist and 3 nurses (1 midwife nurse) with 20 patient beds. According to Department of Health of Ca Mau, existing diseases at the project area are mainly bronchitis, pneumonia, diarrhea, petechial fever and typhoid.

Education: Khanh An commune has 9 schools with 39 rooms and 106 teachers. The

total pupils are 2,258 in the year 2005-2006 [People Committee of Khanh An commune] including:

+ Secondary school: 882 pupils (reduce 190 pupils than last year) + Primary school: 1,113 pupils (reduce 168 pupils than last year) + Garden school: 263 pupils (increase 33 pupils than last year)

3.4.8 Cultural relics, archaeology and tourism Ca Mau has many natural conservation areas with many beauty landscapes, bird sanctuaries, melaleuca and mangrove forests... attracting ecological tourists. However, due to the disadvantage of transportation, Ca Mau tourism hasn't developed yet. At the project area, there is CaoDaism pagoda - Cuu Linh Chau, which is situated very close to Cai Tau confluence. It was removed before constructing gas-power-fertilizer complex. 3.4.9 Existing pollution sources before having project



▪ Domestic waste At the project area, the hygiene situation of Cai Tau residential area is very poor. There is a lot of garbage along the canal banks. Rubbish is discharged directly into the canals where a lot of nylon bags and fruit peels are drifted. Along Ong Doc river-banks, there are some existing temporary domestic waste landfills caused pollution to water source. Existing waste treatment of Ca Mau province:

- At present, the waste treatment system is unavailable in the province. The solid domestic wastes from the fishery processing factories are discharged directly into river.

- In province, there is only one domestic waste landfill located in Hamlet 1, An Xuyen commune and on national highway No. 63 in the suburb of Ca Mau city, where all domestic wastes are collected and transported by road transportation.

Industrial production activities

In Khanh An commune, Ngoc Sinh Processing Fishery Factory is operating. Its wastewater is discharged directly to the canal 21 of Cai Tau river. This has caused water pollution for this canal and Cai Tau river in May, 2005. Khanh An commune People Committee and Department of Natural Resource and Environment had warned and administrative finned. Ngoc Sinh factory promised to make good and a waste treatment system has been built . Boats/ships activities

Boat/ship density in Ca Mau province is very high. Moreover, the means (barge, passenger boat, transportation boat, wooden barge, high speed canoe and motorized sampan, etc.) and boat's capacities are quite difference, especially steersmen were trained in a short training course or without any course. So, the potential risk of boat/ship collision is very high. In addition, a significant amount of lubricant, residue oil are discharged from dense boats activities to the rivers/canals that causes water pollution and destroys aquatic environment. Aquacultural activities

Wastewater and disposal mud from shrimp ponds are pollution sources to water quality of surrounding areas. Especially, at the shrimp industrial cultural areas along Ong Doc river where has no disposal mud treatment system, but were discharged directly into the river. In addition, the utilization of food and preventive and protection medicine for aquacultural development had partly caused water pollution. At Ong Doc estuary, wastewater from fish powder processing factories, sea product processing factories, fish source processing factories... were discharged directly into Ong Doc river causing serious pollution to the aquatic enviroment. It is noted that before having presence of Ca Mau gas-power-fertilizer complex (2000-2003), there are some existing diseases causing shrimp-death at aquacultural areas along the river banks of Ong Doc, Minh Ha, Trem and Cai Tau river/canals. This originates from the unprompted pattern changed from rice field to shrimp pond, the polluted water or the disease. Therefore, this phenomenon will continue happening after Gas-power-fertilizer complex coming into operation. It is necessary to have cooperation between Department of Natural Resource and Environment, Department of Fisheries and Project Management Board in order to verify clearly causes/ reasons, not accuse from power plant operation. Wastewater generated from power plants is always treated and managed according to discharge permits, which are issued by Ministry of Natural Resource and Environment.



U Minh melaleuca forest fire [14] In the dry season 2002, several serious forest fire accidents were happened at U Minh melaleuca forest. Forest fire had caused great damages to U Minh old malaleuca forest. In which more than 4,600 ha U Minh Ha forest area was fired and 3,800 ha was completely destroyed. More than 4,000 ha primary U Minh Thuong melaleuca forest was fired. In the recent years, dry climate, long lasting hot sunshine, forest area is drought sooner, water in canal system is not adequate for transportation and fire fighting in time. In the melaleuca forest, there is a thick vegetation layer, so fire is easy to spread out a large area and causes big fire. On the other hand, the custom of getting honey, illegal hunting birds and fish in the melaleuca forest and careless fire use is always a threaten in the dry season. At present, measures of fighting protection and prevention are not secure that forest fire will not happen in the coming years. In recent years, local authorities paid attention to the forest fire fighting and prevention works together with the favourable climate (heavy rain), the forest fires occurred not so many. In 2002, in the whole province, there are 66 forest fires which fired area are about 4,423 ha. In the dry season in 2003-2004, there are 3 forest fires that damage 3,200 m2 forest. The happening of fire forest in Ca Mau province in 2005 [3] is shown in Table 3.23.

Table 3.23 FIRE FOREST ACCIDENTS AT THE BEGINNING OF 2005

Time Location Area of

damaged forest (ha)

Solution Reasons

(if defined)

14/03/2005

Tran Van Thoi forest fire, sub-area 051 0.16

-Forest-fighting means: high capacity pumps

-Fire-fighting force: 50 persons

Careless smoking while tidying up

Tran Van Thoi forest fire, sub-area 50

9 Means and fire-fighting forces at site

-

15/04/2005 Vo Doi Forestry Station of special-use forest

10

Means and fire-fighting forces on the spot

-

Source: Existing environment of Ca Mau province, 2005



Section 4.

POTENTIAL ENVIRONMENTAL IMPACT ASSESSMENT As mentioned in chapter 2, Ca Mau 2 power plant is carried out on basic of two times multiple of the Ca Mau 1 power plant. It was constructed in area of 10ha, belonging to the land of proposed fertilizer plant. Due to capacity and configuration of Ca Mau 2 power plant is similar to Ca Mau 1 power plant, therefore the environmental assessment for the Ca Mau 2 power plant will similar to Ca Mau 1 power plant.

4.1 CONSTRUCTION, INSTALLATION AND COMMISSION PHASES 4.1.1 Main sources of environmental impacts Due to area of the Ca Mau 2 power plant had been cleared, vegetation cover was removed and it was filled up to 1.5m since 2002, so in present, the site foundation needs to consolidate and treat only. The activities related to construct temporary port for transporting super size and super weight equipment and imported DO jetty for the two power plants were mentioned in EIA report of Ca Mau 1. So the main polluted sources in construction and installation/commission processes of Ca Mau 2 power plant are summarized in table 4.1.

Table 4.1 MAIN SOURCES OF ENVIRONMENTAL IMPACTS DURING COSTRUCTION/ ISTALLATION AND COMMISSIONING PHASES

Environment Polluted source Pollutants Level Air -Filling up and consolidating foundation;

-Equipment installation -Operation of constructive equipment; -Painting exposed surface -Equipment commissioning and Testing

-Dust, CO, NOx, SOx, VOC, CH4, Hydrocarbon

Water - Piling -Embankment building around the plant -Transportation of construction material and equipment -Boat/ship activities

-Sludge -Liquid wastes -Solid wastes -Alum water: Fe2+, Al3+.

Soil -Filling up and consolidating foundation -Dredged sludge disposal -Construction wastes disposal -Domestic sewage disposal

-Construction wastes -Domestic sewage -Hazardous wastes

Biology -Piling -Embankment building around the plant -Transportation of construction material and equipment -Boat/ship activities

-Sludge -Liquid wastes -Solid wastes



4.1.2 Impact on physical environment 4.1.2.1 Air quality Dust Due to urgent demand about construction progress of the both plants 1&2, so many works will be deployed at the same time. The process to conduct with works: excavating, filling up, sand pump, consolidating foundation, building works used brick, stone, steel, etc… will generate a significant quantity of dust. According to the analyzed results of dust content at the project area in December 2005, the dust content at project area is higher than allowable standard due to consolidating foundation activities for the Ca Mau 1 power plant. Above construction activities together with the operations of vehicles transporting sand from sand unload sites to filling up sites will generate large dust at construction area and maybe affect to Cai Tau residential and resettlement area. Effect duration from above activities will last appropriately 16 months. Dust also generates from polishing, welding and painting activities during installation of gas turbine units, fuel gas supplying pipeline, cooling tower and storage tanks. The fine dusts and paint vapor might affect to respiratory organs of labors working directly in the construction site and cause asthma, pneumonia and bronchitis disease. In brief, dust generated from the power plant construction and installation activities will cause direct impacts on the labor force in project area and indirect affects on 300 households in the resettlement area and Cai Tau residential area. Impact level is considered as moderate in the first year and then reduces gradually to minor level in the following years of construction and installation phase. Emissions Emission from construction equipment Operation of construction equipment will discharge a significant quantity of different emission gases into environment depending on the transportation ways and operation of each equipment, including:

Activities of sand backfill and construction material transportation: Due to the project area can not satisfy construction material demand, so materials such as: sand, cement, and stone will be transported from An Giang, Kien Giang and Can Tho provinces. As calculation, backfill sand is transported to unload site by barge and then it will be transported to the consolidating foundation area by trucks of 10 – 12 tons (7m3). Depending on the operating capacity of construction equipment, used fuel is estimated of 60 litters DO/shift for dredgers and trucks and 80 – 90 litters DO/shift for heavy machines such as rammer, grader, digger and pile driver. This work is completed in 16 months.

Transportation and installation activities: installation process of equipment units and

utility system has to use heavy cranes, equipment installing machines, lorries for the power plant. It is estimated that 5 cranes, 10 trucks, 2 air compressors will be used for transportation. Period for equipment installation is about 18 months.

According to the quick assessment method of World Health Organization WHO 1993 [15], estimation emission volume of diesel engines used in the construction period is summarized in table 4.2.



Table 4.2 ESTIMATION EMISSION VOLUME FROM OPERATION OF CONSTRUCTION EQUIPMENT IN CONSTRUCTION AND INSTALLATION PHASE

Operation Amount

(piece) Used

DO (ton)TSPb

(Ton) COc

(Ton) SO2

a

(Ton) NOxd

(Ton) VOCe

(Ton)1. Operation of consolidating foundation (16 months) Dredger 14 565 2.43 7.91 0.034 39.55 2.26 Pile driver 10 538 2.31 7.53 0.032 37.66 2.15 End dump lorry 70 2.822 12.11 39.51 0.170 197.54 11.29Bulldozer 10 538 2.31 7.53 0.032 37.66 2.15 All kind of rammers 7 376 1.62 5.26 0.023 26.32 1.50 KOBE digger 11 591 2.54 8.27 0.036 41.37 2.36

Total 1 23.32 76.01 0.327 380.10 21.712. Transportation and installation power plant (18 months) Air compressor 2 151 0.65 2.11 0.009 10.57 0.60 Crane 5 302 1.30 4.23 0.018 21.14 1.21 Truck 10 454 1.95 6.36 0.027 31.78 1.82

Total 2 3.25 10.59 0.045 52.92 3.03 According to above data shows emission in the filling up and consolidation period is the most considerable. However, because the construction equipment operating at ventilated rural plain area so the emission will be dispersed quickly and impact level is considered as small and only limited within the project area. Emission from commissioning phase

In commissioning phase, Ca Mau 2 power plant will be tested by combined cycle in about 40 days by natural gas and DO fuel under loading regime of 100%. Emission volume and component of exhausted gas from stacks are presented in table 4.3.

Table 4.3 COMPONENTS AND EMISSION VOLUME IN TESTING PROCESS FOR CA MAU 2 POWER PLANT

Pollutant content

(mg/m3) Testing regime* Flow rate

(m3/s) Time (Day)

ToC

CO NOx SOx Testing by natural gas Full loading 100% 674 30 97 12.5 51.3 -

TCVN 7440-2005 180* 210 252 Testing by DO fuel Full loading 100% 736 10 138 12.5 149.8 277

TCVN 7440-2005 180* 504 420 Note: * Apply: TCVN 6993:2001 with KCN=0.6 (A level technology)

Karea=1.2 (industrial zone in pure rural area) Q3 corresponding to discharge sources with released flow rate > or = 20,000m3/h

In the first test, a significant black smoke will generate including dust and undesirable products such as lubricants adhered to surface of heatproof equipment. In case of testing by natural gas, volume of CO and NOx in emission gas is much lower (4.1 to 14.4 times) than Vietnamese standard TCVN 7440:2005. In case of testing by DO fuel, volume of SOx, NOx in emission gas are still lower 1.5 to 3.4 times than TCVN 7440:2005. Moreover, as planning, the commissioning and testing duration



run mainly by natural gas, DO testing duration is only 10 days. So impact level in this case is considered as small level. 4.1.2.2 Noise and vibration The same with construction and installation equipment of the Ca Mau 1 power plant, the operation of heavy machines (Pile driver, compressor, crane and concrete mixer. etc.) will generate noise which will directly affect to workers working in project area and adjacent areas. Especially, the noise generated from pile driver (75dB) is not great in comparison with the noise generated from bulldozer but stretched, so it makes uncomfortable for local people, especially at night time.

Moreover, the direct driving a great quantity of concrete pile for foundation consolidating to the depth of 60 meters not only generated noise but also cause strong vibrating within radius of 200 meters in the project area. Thus, noise generated from construction equipment ranging within 75 – 93 dB will directly affect to health of construction workers and residents living in Cai Tau area within radius of 200 meters, especially at night. Impacts level is assessed as small but uninterrupted during working process. 4.1.2.3 Impacts on water quality Ca Mau 1 & 2 power plant project is located next to Cai Tau confluence area of three rivers (Cai Tau, Trem and Doc river). Due to the road system in the project area is not developed, therefore all transportation activities of construction material and equipment units of the power plan must be transported by waterway system. Therefore many construction activities of the project may affect to water quality including: Transportation activities for construction material and super size, super weight

equipment; Dredge activities and expanding port area; Piling for consolidating foundation. Domestic wastewater from camps of construction workers.

Above activities will affect to environment as follows: Make changes local current regime due to dredging and expanding the port area. The

excavating port too deep will make the current from Trem River increased toward the port.

Increase alum washing out process at the beginning of rainy season due to piling and excavating activities. Moreover, during foundation consolidation process, vacuum pump of alum water to the adjacent river/canal will make decreasing pH of Cai Tau, Trem and Doc rivers (pH value in the range of 3.81 to 4.25) and increased toxicants content such as H+, Al+3, Fe+2, SO4

-2.

Disturb water environment due to activities of expanding port and boat activities for equipment and material transporting and increase suspend solid (TSS) and pollutants in the sediment at Cai Tau confluence area. The affected area within distance of 1 to 3 kilometers from dredging site with the impact level is considered as medium during construction phase.

Hydrotest water: hydrotesting process of pipeline system will be carried out at each section so the process will be simply so much and save a lot of testing water. As planed, pipeline hydrotesting process will use mineral water and tank hydrotesting will use portable water supplied by Ca Mau Water Supply Company and no chemical will be



used. Maximum water used for hydrotest is about 5,000m3 for oil storage tank. After testing, all hydrotested water will be discharged to rainy drainage system of the plant to the Cai Tau river and impact on surrounding environment is insignificant.

Domestic wastewater generated from construction area will be discharged through the hygienic septic tanks system. During the plant construction phase, there are about 1500 to 2000 persons working within 28 months. Estimated domestic wastewater quantity in the construction/installation phases is about 189,000 to 252,000 tons. However, wastewater from the camp area of construction workers located outside the plant area must be discharged through the temporary toilet system next to cannel/rivers. So it can cause organic pollution and water-born diseases such as: cholera, typhoid, dysentery.

Therefore when undertaking all construction activities of the CM1 and CM2 power plants at the same time will reduce significant pH value of Cai Tau, Ong Doc, Trem rivers. The alum pollution level due to construction activities of the power plant to water environment at Cai Tau confluence is considered as medium in rainy season (from May to October) in the two first years of construction phase and as small in the following year for the adjacent areas of project in the range of 5 to 7 kilometers on the downstream of Cai Tau and Ong Doc rivers. 4.1.2.4 Impacts on soil quality

Change of soil structure Due to geological characteristics at the plant area, there is a weak soil layer with a thickness of 17 – 20 meters, therefore all the power plant area must be filled up and consolidated to the elevation of +1.97 to +2.84 meters by pre-loading combined to vacuum compressing method. In the area where super weight equipment will be installed such as transformer units, gas turbines, cooling tower and storage tanks, it must be piled the concrete piles to the depth of 60meters. Total of the concrete piles must be piled about 329 concrete piles with 100m in length and 49,000m of cram concrete piles. Above construction activities cause strong disturbance to the soil environment, direct affect to 10 ha of agricultural area and change of soil structure from wetland (high porosity, high compressibility, high melt ability) to construction soil (low porosity, low compressibility,…).

Soil pollution due to solid wastes disposal Non-hazardous solid wastes generated during construction and installation phase include: metal, plastic, small amount of other materials from construction phase and used packaging from installation and commissioning process. Hazardous wastes are paints, solvent, welding rods, engine and waste oil are estimated as very low. It is noted that in the rainy season, the heavy rain may wash out contaminants on surface to water source and the construction in rainy season will be more complicated and the incident risk may be increased at different levels. According to the criteria of Viet Nam Hygiene and Public Health, quantity of domestic solid waste generated during construction phase (28 months) is estimated in range from 1,071 to 1,428 tons. All of them will be collected and treated by Ca Mau Urban Hygiene Company to limit soil pollution. Briefly, the project activities during the site preparation, construction and installation phase will lose surface organic soil, decrease considerably agricultural land area (10 ha), change of land-use, soil structure and enhance alum leakage ability. However, the land-use purpose of project area is converted from agricultural land to industrial land. Therefore, impact level on soil environment is assessed as moderate during construction phase.



4.1.3 Impacts on biological environment Due to the plant ground was cleared and surface soil layer was removed since 2002, so at present, the Ca Mau 2 Power plant site has filled up by sand and the vegetation cover near the plant area is not diversity. Therefore, the plant constructive activities are not affected to the terrestrial ecosystem.

Expanding port activities to serve for the both CM1 and CM2 plants will cause sediment disturbance at Cai Tau river area, that cause affect on aquatic ecosystem especially affect to bottom fauna species. However, according to the analyzed results in environmental baseline report, which was carried out at the project area in 2002 showed that the aquatic species is very poor. Thus, impact level on the aquatic ecosystem during construction phase is assessed as low to moderate. 4.1.4 Interactions Coordination between investor and constructors

The progress rate of Ca Mau 2 power plant is very urgent. Beside, the constructor of the Ca Mau 1 power plant is also the constructor of the CM2 power plant, therefore at the same time, both CM1 and CM2 power plant are constructed so the reasonable arrangement of execution equipment and coordinate the work between the both plants are necessary. The management of constructional works at the same time in the same industrial units will not avoid the difficulties about manpower and material power sources. Therefore, if there is not synchronous coordination between construction units as well as constructors and sub-constructors, that will generate of complicated problems. Beside, the presence of large labors coming from different areas will cause disturbance living condition of local people such as increasing cost of living, as well as raising some conflicts between workers and local residents. Activities of local boat

The project area is surrounded by large rivers as Cai Tau, Trem and Ong Doc, so before having the gas-power-fertilizer complex, the boat density was busy including high speed passenger boats, barges, oil and petrol transportation ships. According to statistical of A wharf management board of Ca Mau city, everyday the quantity of passenger boats (25 – 45 persons/boat) and constructive material, oil and petrol transportation ships is about 104 boats. In which the passenger boats are 66 boats/day with berthing frequency of 30 minutes. Furthermore, due to high quantity of local residential boats from Cai Tau area and inland areas to Cai Tau market trading (at least, each household has one boat); therefore boat density in this area increase highly. Moreover, due to road traffic system has not yet developed, so all transportation of agricultural products and constructive material and traffic of local residents are by waterway means. It is noted that, almost owners of traffic means do not obey strictly waterway traffic regulations, especially speedy boats and boats, so potential boat/ship collision risk is relatively high. As development the revised Ca Mau power plant project, above boat/ship operations will cause an interactive effect with barges/boats back and forth the port area. And their presence as well as ships for supply and constructive material transportation of the project will also cause increasing boat density, which is already crowded at this area. Constructive activities will obstruct partly the living of local resident and make increasing of potential risk of ship collision between transportation boats and big passenger boats, speed – canoes and constructive barges or between ships with port works, if lacking cooperation of project management board and local authorities as well as ship owners don’t obey the signal buoy system.



4.2 OPERATION PHASE 4.2.1 Main source of environmental impacts In operation phase of the power plant, main activities can effect to environment including: - Operation of gas turbine using natural gas or DO; - Operation of cooling tower; - Cooling water intake and discharge; - Waste disposal. Above activities will generate emission gases, wastewater and solid waste including:

− Emission gases from HRSG contain NOx, CO and in case of using DO fuel, it contains more SOx. Emission gases emit to environment through the main stack of 40m height;

− Wastewaters including: regular discharge cooling water with highest temperature is about 35oC and in case of tail gas incident (rarely occur) the highest temperature is 40oC; discharge water from boiler is demineralization one containing small content of phosphate, ammoniac and hydrazine which are regular routed into temperature exchange tower and then together discharge with cooling water; and other industrial wastewaters;

− Other solid wastes including: industrial waste, mud waste from wastewater treatment system, oil sludge waste and domestic waste.

If there are not reasonable management or unreasonable disposal for these pollutants, that will cause affect to environment quality.

4.2.2 Impacts on physical environment 4.2.2.1Air quality Ambient air quality of the power plant may be affected by emission gases from operation of turbine in the plant and dust, steam from operation of cooling tower. Besides, noise generated from the plant also affects to workers working in the plant and local residents living near the plant. 1. Impacts of regular emision gases from turbines Similar to the configuration of Ca Mau 1 power plant, Ca Mau 2 power plant includes two gas turbines and one steam turbine that designed to burn both natural gas and DO fuel. The main fuel for operation of the power plant is natural gas from PM3-CAA and Cai Nuoc blocks. When the gas supply source is interrupted, the power plant will use imported DO fuel with highest content of sulphure of 0.5%wt and using quantity of about 108.5 tons/hour.

Load and content of regular emission gases from gas turbines Emission gases generated from operation of the plant will discharge to the environment through two main stacks of 40m height. Emission gases generated from natural gas burning is mainly NOx, CO and a small quantity of unburned hydrocarbon. In case of DO burning, the mainly emission gases consist of NOx, SO2, CO and dust (ash). Estimating load and content of regular emission gases from the combine cycle power plant through main stack are ssummarized in table 4.4.



Table 4.4 LOADS AND CONTENT OF REGULAR EMISSION GASES THROUGH THE STACK OF CA MAU 2 POWER PLANT

Emission gases Parameter Unit

Gas burning Do burning TCVN

7440:2005 Stack coordinate X=1021746,52; Y=396813

X=1021746,52; Y=396853

Stack height m 40 Stack diameter m 6,5 Emission gas flow rate Nm3/s 674 736 Emission gases temperature oC 97 138 Emission gas velocity m/s 20 21 Emission gas component SOx mg/Nm3 0.85 277 252a

420b

NOx mg/Nm3 51.3 149.8 210a

504b

CO mg/Nm3 12.5 12.5 180c

Dust mg/Nm3 5.0 10.0 42a

126b

Note: DO with sulfur content of 0.5%kl. a- Discharge standard in case of using gas fuel b- Discharge standard in case of using oil fuel c- Comply TCVN 6993-2001 In both cases, natural and DO burning, emission gas components at stack outlet are lower than dicharge standard of thermo-electric industrial branch TCVN 7440:2005 (for NOx, SOx and dust) and TCVN 6993:2001 (for CO). Besides, to assess the environmental combinative impacts of both plants 1&2, quantity of regular emission gases from stacks of the Power plant 1 will be also calculated in emission gas dispersion modeling.

Selected options for calculating dispersion ability of air emission Ca Mau 2 power plant is located next to Ca Mau 1 power plant, so following options are selected for calculating dispersion ability of air emission:

Option 1: Calculation of dispersion ability of air emission from Ca Mau 2 combined cycle power plant through two main stacks of 40m height in case of 100% natural gas burning;

Option 2: Caculation of dispersion ability of air emission from Ca Mau 2 combined cycle power plant through two main stacks of 40m height in case of using 100% DO fuel with maximum sulphur content of 0.5%wt

Option 3: Combined calculation of dispersion ability of air emission from CM2 combined cycle power plant through two main stacks of 40m in height and CM1 combined cycle power plant through two main stacks of 40m height in case of using 100% natural gas;

Option 4: Combined calculation of dispersion ability of air emission from CM2 combined cycle power plant through two main stacks of 40m height and CM1 combined cycle power plant through two main stacks of 40m height in case of using 100% DO fuel with maximum sulphur content of about 0.5%wt.



Modeling for calculating of regular air emission dispersion ability Air emission dispersion modeling ISC- ST3 – version 3.2 (The Industrial Source Complex Short-Term) is used as calculating dispersion ability of regular air emissions in the plant. This modeling established by United State Environment Protection Association (USEPA) is used to determine pollutant contents from regular emission source, stacks, area and uncovered tanks.ect. It was established basing on the co-ordination of different dispersion modeling algorithms to assess impacts on air quality of emission gases. The basic principal of modeling is Gaussian equation (Appendix 2). ISCST3 modeling uses meteorological data for each hour to calculate the raising, moving, dispersion and accumulation of air column in a specific area. The modeling will calculate content or accumulation for each discharge source or receive source for each input meteorological data for each hour and average meteorological data for short-term or all of stage. Before running specific options, this modeling has always been tested with specific sample case (same input data running same discharged modeling) to determine modeling accuracy. In case output result of testing running is in accordance with the sample result, this proves that air dispersion modeling has high accuracy. In practical, ISC-ST3 modeling version 3.2 using in RDCPSE is American commerce one with high accuracy. This is acknowledged by all over the world and using it to calculate air emission dispersion for discharge sources and area. In Vietnam, this modeling is used for calculation air emission dispersion for most of key projects such as Dung Quat petroleum refinery plant, Phu My Fertilizer plant & Power plant complex, Dinh Co Gas processing plant, Ba Ria power plant, Dinh Co – Ba Ria - Phu My gas distribution plant, Thi Vai LPG Terminal, CM1 Power plant... To compare with air emission dispersion results at the power plant which was modelised in detail EIA report for Ca Mau power plant (approved on april/2005), in this report has used meteorological data (temperature, wind velocity, wind direction, cover level, sunshine) recorded at Ca Mau meteorological station in 4 times/day within 1998-2000 but these data were imitative calculated for 24 hours/day by the Southern meteorological station. Especially, solar radiation data used for calculating atmospheric stability and disturbance is based on the data recorded at Can Tho meteorological station (which was chosen for calculating the solar radiation for all of Cuu Long river delta area by the Southern meterological station) In calculation process, topography factor and elevation of neighboring buildings have been considered . But due to the specific charateristics of the power plant area is a plain region, there are not obstacles here (building, mountain, hill .ect.). therefore, the modeling calculation is only considered to elevation of ambient building of the plant. The height and distance of ambient buildings of Ca Mau 2 power plant to the main stacks are calculated in air emission dispersion modeling are shown in table 4.5: Table 4.5 THE HEIGHT AND DISTANCE OF AMBIENT BUILDINGS TO THE MAIN STACK

OF CA MAU 2 POWER PLANT

No. Ambient building coordinate Height (m) Distance to the main stack (m)

2 Cooling tower X=1021772.29 Y= 3966777.61

15.18 18.70

Fuel tank 1 X=1021799.79 Y=396959.10

17 53.18 3

Fuel tank 2 X=1021741.79 Y= 396959.10

17 53.18



Ground air emission content was forcasted for a range of wind velocity that corresponds to each asmopheric stability and a real set of mixing height. All of wind direction was modeled to calculate variation of air emission plume corresponding to different wind directions.

Modeling results The result of air emission dispersion modeling of the CM 2 power plant and combination with the emisson gas of the CM 1 plant will be assessed based on TCVN 5937-1995 – maximum allowable concentration of some pollutants in ambient atmosphere is summarized in tables 4.6 & 4.7. Table 4.6 MAXIMUM AVERAGE GROUND CONCENTRATION OF POLLUTANTS WHEN RUNNING FOR CA MAU 2 POWER PLANT FOLLOW OPTION 1&2 – WITH OBSTACLE

Average 1 hour Average 24 hours Average year Stack

Maximum content (μg/m3)

Distance (m)

Main directio

n


Distance (m)

Main direction


Distance (m)

Main direction

Option 1: CM 2 power plant using 100% natural gas SO2

1 0.234 1616.9 SE 0.083 3179.4 W - SW 0.009 4278.6 E-NE 2 0.233 1593.1 SE 0.084 3219.4 W - SW 0.009 4250.3 E-NE Both 0.467 1604.9 SE 0.167 3199.4 W - SW 0.018 4264.4 E-NE TCVN 5937:1995 500 300 NOx

1 14.936 1616.9 SE 5.288 3179.4 W - SW 0.588 4278.6 E-NE 2 14.907 1593.1 SE 5.363 3219.4 W - SW 0.587 4250.3 E-NE Both 29.844 1604.9 SE 10.651 3199.4 W - SW 1.175 4264.4 E-NE TCVN 5937:1995 400 100 CO 1 3.639 1616.9 SE 1.288 3179.4 W - SW 0.143 4278.6 E-NE 2 3.632 1593.1 SE 1.306 3219.4 W - SW 0.143 4250.3 E-NE The both 7.270 1604.9 SE 2.595 3199.4 W - SW 0.286 4264.4 E-NE TCVN 5937:1995 40.000 5.000 - Suspended dust 1 1.459 1616.9 SE 0.517 3179.4 W - SW 0.0575 4278.6 E-NE 2 1.457 1593.1 SE 0.524 3219.4 W - SW 0.0574 4250.3 E-NE The both 2.917 1604.9 SE 1.041 3199.4 W - SW 0.114 4264.4 E-NE TCVN 5937:1995 300 200 - Option 2: CM2 power plant using 100% DO as fuel SO2

1 75.158 1958.7 South 18.090 3558.6 South 2.041 4278.6 E-NE 2 74.759 1959.6 South 17.865 4358.2 South 2.032 4250.3 E-NE The both 149.917 1959.0 South 35.565 3558.8 South 4.072 4264.4 E-NE TCVN 5937:1995 500 300 NOx

1 40.070 1958.7 South 9.644 3558.6 North 1.088 4278.6 E-NE 2 39.856 1959.6 South 9.524 4358.2 North 1.083 4250.3 E-NE The both 79.926 1959.0 South 18.961 3558.8 North 2.171 4264.4 E-NE TCVN 5937:1995 400 100 CO 1 3.344 1958.7 South 0.805 3558.6 South 0.091 4278.6 E-NE 2 3.326 1959.6 South 0.795 4358.2 South 0.090 4250.3 E-NE The both 6.670 1959.0 South 1.582 3558.8 South 0.181 4264.4 E-NE TCVN 5937:1995 40.000 5.000 - Dust 1 2.713 1958.7 South 0.653 3558.6 South 5.412 4278.6 E-NE 2 2.699 1959.6 South 0.645 4358.2 South 0.073 4250.3 E-NE The both 5.412 1959.0 South 1.284 3558.8 South 0.147 4264,4 E-NE TCVN 5937:1995 300 200 - Note: - SE: South East W-SW: West- South West - E-SE: East-South East - Using DO, Sulfur concentration: 0,5%wt



Table 4.7 MAXIMUM AVERAGE GROUND CONCENTRATION OF POLLUTANTS WHEN RUNNING FOR THE BOTH PLANT 1&2 FOLLOWING OPTION 3&4 – WITH OBSTACLE

Average 1 hour Average 24 hours Average year Stack

Maximum content

(μg/m3)

Distance (m)

Main direction


Distance (m)

Main dispersion direction


Distance (m)

Main direction

Option 3: CM2 & CM1 power plants using 100% natural gas SO2 0.911 1775.8 S-SE 0.331 3774.6 South 0.030 4020.2 West TCVN 5937:1995 500 300 NOx 58.180 1775.8 S-SE 21.110 3774.6 South 1.924 4020.2 West TCVN 5937:1995 400 100 CO 14.174 1775.8 S-SE 5.389 3774.6 South 0.469 4020.2 West TCVN 5937:1995 40.000 5.000 - Dust 5.686 1775.8 S-SE 2.063 3774.6 South 0.188 4020.2 West TCVN 5937:1995 300 200 Option 4: CM2 & CM1 power plants using 100% DO as fuel SO2 288.587 1774.6 South 74.266 3774.6 South 6.825 4020.2 West TCVN 5937:1995 500 300 NOx 153.856 1774.6 South 39.594 3774.6 South 3.639 4020.2 West TCVN 5937:1995 400 100 CO 12.839 1774.6 South 3.304 3774.6 South 0.304 4020.2 West TCVN 5937:1995 40.000 5.000 -

Dus 10.418 1774.6 South 2.681 3774.6 South 0.246 4020.2 West TCVN 5937:1995 300 200 Note: - S-SE: South-South East - Burning by DO, Highest sulphur concentration: 0,5%wt

Environmental impacts of regular emission gases Impacts of air emission from stacks of Ca Mau 2 power plant as well as the both CM1 and CM2 power plants are assessed basing on the worst situation due to using maximum ground concentration as forcast for above pollutants to compare with air quality standard. This concentration is found at specific sites. The concentration at other places is lower. When the plant uses DO fuel, the emission gases in this case are calculated in the worse case with sulphur content of 0.5%. Diagram of pollutants dispersion: SOx, NOx and CO in four selected options are showed in Appendix 2.

Maximum ground average concentration of pollutants from particular stack and both stacks in the plant 2 as options 1 & 2 are summarized as follows:

- SO2 concentration on the ground Maximum average daily ground concentration of SO2 from particular stacks as well as the both stacks in case of using DO (sulfur content of 0.5%wt) is higher than case of using natural gas, but it is still much lower than allowable ambient air concentration of TCVN 5937:1995. Maximum hourly and daily average ground concentration of NO2 is within 1.6 to 3.2 kilometers from foot of stacks towards Southeast and West-South West in case of using gas or South in case of using DO fuel.

- NOx ground concentration Maximum average hourly and daily ground concentration of NOx from stacks in Ca Mau 2 power plant using DO fuel is also higher 2.7 times than using natural gas. Maximum 1 hour and 24 hours average ground concentrations of NOx from two stacks using DO fuel are 79.93μg/m3 and 18.96 μg/m3 respectively (far about 2km from stack toward the South or 3.6km toward the East – Northeast) are much lower than allowable standard of 400μg/m3 for average 1 hour and 100 μg/m3 for average 24 hours.



- CO ground concentration

Maximum average hourly ground concentration of CO from stacks of the CM2 power plant in both cases using natural gas and DO fuel is 6.67 – 7.27 μg/m3, at place far about 1.6 - 2km from foot of stack toward the Southeast or the South. This concentration is much lower than ambient air environment standard (40,000 μg/m3).

- Dust concentration on the ground Maximum 1 hour and 24 hours average ground concentration of dust in case of using DO as fuel (5.411μg/m3 and 1.28μg/m3 respectively) is 2 times higher than case of using natural gas (2.917μg/m3 and 1.041μg/m3 respectively) and are much lower than Vietnam standard (TCVN 5937:1995).

Thus, pollutants generate due to operation of Ca Mau 2 power plant are very smaller and lower than ambient air environment standard.

Maximum average ground concentrations of pollutants dispersed from four stacks of both plant 1&2 following options 3 & 4 are summarized as follows:

When Ca Mau 2 power plant comes into operation in March, 2008, Ca Mau 1 power plant has been stabilized operation. So environmental impact from regular emission gases of Ca Mau 2 power plant will be assessed in combining with air emission impact of Ca Mau 1 power plant. Result of air emission dispersion modeling from four stacks of both CM1 and CM2 power plants is summarized as below:

- In worst case, when the both plants are using DO with sulfur content 0.5 % wt, maximum average daily ground concentration of SO2 is 74.266μg/m3. This concentration is lower than ambient air environment standard of 300 μg/m3 (TCVN 5937:1995).

- NOx ground concentration is highest when both plants using DO fuel. Maximum hourly and daily average ground concentrations are 153.856 and 39.59 μg/m3 respectively. Those concentrations are also lower than allowable limit of ambient air environmental standard.

- CO ground concentrations in case of using natural gas as well as in case of using DO fuel are almost the same and are very small comparing with Vietnamese standard (TCVN 5937:1995).

- When Ca Mau 1 and Ca Mau 2 power plants using DO as fuel, maximum daily average ground dust concentration is about 2.68μg/m3 that is very small comparing with allowable standard.

According to the result of environmental baseline survey at Ca Mau 2 power plant area on December 2005, contents of pollutants are as follows:

- SO2: 38 μg/m3

- NOx: 27 μg/m3 - CO: 3500 μg/m3

Regular air emission dispersion from the operation of Ca Mau 2 power plant in both cases of using 100% natural gas and 100% DO as fuel with maximum sulfur content of 0,5%wt adding to existing environment concentration is still lower than allowable limit of ambient air environmental standard (TCVN 5937:1995). So, air emission of Ca Mau 2 power plant in the both case of using natural gas and DO as fuel will not cause significant impact on air environment of the area.



Due to CM2 power plant is gas turbine combined cycle power plant, emission temperature at stack outlet is not high (97oC). Furthermore, Ca Mau power plant is built on agricultural area and it is not obstructed by any building. So air emission from stack of 40m height will not cause heat pollution for ambient air environment. 2. Impacts of dust and steam from cooling tower system. Operation process of the cooling tower system follows the obligatory cooling principal. Cycle water sprays down through tap that will be continuously knocked against net bar and wind will be sucked from underneath to make very small water drops. These drops contact air causing maximum increasing heat exchange surface. Process of wind inverse blowing from underneath will take away considerable water and dust (containing water) to the atmosphere, causing local increasing the dust concentration at the adjacent area of cooling tower. Furthermore, the continuous operation process of cooling tower will cause sedimentation on the surface of heat exchange system and net box. That will cause increase dust content in water sweeping to the atmosphere. However, scale of dust dispersion only limited in plant area and impact level is assessed as minor and long-term during the plant operation. 3. Impacts of noise In the operation phase of the power plant, the noise mainly generates from gas and steam turbines, fans of cooling tower system and main pumps (supply water, condensed water, cooling water.) These equipment continuously operating and make noises during 24 hours in day. Similarly with Ca Mau 1 power plant equipment, Ca Mau 2 power plant equipment are designed with purpose to limit and reduce noise to ensure the allowable standards for workers and noise standards for resident living around the plant, such as:

In the plant area, noise from the normal operating of equipment and turbine will be limited under 85dB in distance of 1m and height of 1.5m above the surface of the noisy equipment. In case of incidents happening at exhausted pipe that has limited noise of 100dB in the distance of under 1m from noise equipment (anti-noise coverage) and related pipeline. In general, noise generated from the plant operation will effect directly on labor force, cause tense, headache and may reduce working productivity. The noise impact on the labor force inside the plant is assessed as moderate during the plant operation.

For outside of the plant area: installing the soundproof wall at the gas and steam turbine apartment as well as other equipment generating noise will limit much noise to outside. At the plant boundary, the project will obey noise standards for industrial plants built in the resident area (75dB in daytime and 70dB in nighttime and 50dB in mid-night to morning). Therefore, the noise impact level on the resident area surrounding the plant is assessed as insignificant.

4.2.2.2 Impact on water quality The sources impact on water quality due to operation of Ca Mau 2 power plant as follows: − Cooling water intake for both CM1 and CM2 power plants − Cooling water discharge − Industrial wastewater discharge − Domestic wastewater discharge



To set up discharge site and assess impact level of above affected sources, RDCPSE has used the model of “Calculation of current regime and dispersion of wastewater and cooling water” designed by Associate Professor Dr. Nguyen Tat Dac. This model was built basing on theoretical basis of Japanese wastewater dispersion model 1975 using dispersion calculation of cooling water for Japanese power plant as well as other plants in the world. This model has used hydraulic field from SAL hydraulic model to calculate the water velocity and water level. This model was also used by Netherlands company NEDECO to make the Master plan of the Mekong delta and HASKONING company (Netherland) and used for calculating current regime of waterway route from Ho Chi Minh City - Kien Luong – Ca Mau and utilised to assess the environmental impacts for many projects such as: Phu My power plant, O Mon power plant, projects in Thi Vai – Vung Tau, Saigon – Dong Nai and Mekong delta. The basic calculation of this model is showed at the appendix 3. Input data of current velocity, water level and using capacity to calculation for modeling is taken from hydrographic measure during December 2000 to July 2001. The scale of calculation basing on hydraulic model to calculate for the whole Ca Mau peninsula is limited from Hau River inward and from Cai San to the sea. This model is used for planning projects in Ca Mau peninsula and it was applied to calculate the variation of current regime, water level, temperature and pollutant dispersion ability (ToC, BOD, DO, NH4

+, NO2-, NO3

-, total N...) on the river system controlled by the tide at different using water conditions. The continuous intake of cooling water (2m3/s) and continuous discharge (0.4m3/s) into Cai Tau River also affect to the current variation and pollutant dispersion in treated industrial wastewater into Cai Tau river. Moreover, Ca Mau 2 power plant comes into operation in March-2008, the CM1 power plant are operating regularly and also discharge cooling water and industrial wastewater into Cai Tau river. So when calculating the modeling, all discharges and intakes of both plants (CM1 and CM2 power plants) are also considered to assess combined impacts from their activities:

1. Cooling water intake is 2m3/s for CM1 & CM2 plants; 2. Cooling water discharge is 0.4m3/s of CM 2; 3. Cooling water discharge is 0.4m3/s of CM 1; 4. Industrial wastewater discharge is 0.008m3/s of both plants

On the other hand, the existing of Tac Thu dock and the closing of Tac Thu sluice in dry season for preventing salinity intrusion are selected period for running model of current variation and wastewater dispersion. Options of cooling water intake and wastewater discharge for both CM1 and CM2 power plants are summarized in Table 4.8 and Figure 4.1 (vertical section).

Table 4.8 OPTIONS FOR COOLING WATER INTAKE AND DISCHARGE

FOR CM1 AND CM2 POWER PLANTS

Opt.

Discharge condition Q (m3/s) Intake/discharge site

Coordinate Note

P.0 Current option: present of Tac Thu sluice, but without power plant for comparing Intake cooling water for both CM1 and CM2 power plants

2 Cai Tau river (VT0)

X=1022138.062 Y=397125.328

Discharging cooling water of the CM1 power plant

0.4 Cai Tau river (VT1)

X=1022595.920 Y=396887.920

Discharging industrial wastewater of CM1 & CM2 power plants

0.008 Cai Tau river (VT 2)

X=1022311.527 Y=397024.993

P.1

Discharging cooling water of CM2 power plant

0.4 Cai Tau confluence (VT4)

X=1021946.000 Y=397733.000

- Running in 6 months of dry season (Nov.–Apr.) -The Tac Thu sluice is closed to keep fresh water.



Intake water for both CM1 and CM2 power plants

2 Cai Tau river (VT0)

X=1022138.062 Y=397125.328

Discharging cooling water of the Ca Mau power plant 1

0.4 Cai Tau river (VT1)

X=1022595.920 Y=396887.920

Discharging industrial wastewater of CM 1&CM2 Power plants

0.008 Cai Tau river (site VT 2)

X=1022311.527 Y=397024.993

P2

Discharging cooling water of the Ca Mau 2 power plant

0.4 Cai Tau river (site VT 3)

X=1021964.009 Y=397256.066

Due to two power plants located at area influenced by tide of East Sea and West Sea, it’s heavy rainfall in the rainy season but it seems to have no rain in the dry season. So surplus water occurs in the rainy season and water lacking in the dry season. Therefore, in thermal dispersion modeling of cooling water and pollutant dispersion modeling will only consider and run for six dry months with the worst case of Tac Thu sluice closing to keep water. It’s noted that all sites of cooling water intake (VT0), cooling water discharge of the CM1 power plant (VT1), discharging industrial wastewater of the CM1 and CM2 power plants (VT2) and discharging cooling water of CM2 power plant (VT3 or VT4) are all on the left bank of Cai Tau river (see from Cai Tau confluence) within 1500m in length (from cooling water discharge site of CM1 power plant (VT1) to Cai Tau confluence (VT4). The existing of the water intake and discharge area can be summarized as follows:

The Cai Tau river’s width is about 60m, in the future it will be enlarged for a port of 160m. The river water is saline intruded in the dry season, the values of pH, salinity, and turbidity vary clearly depending season. Basing on analysis result of water quality in December, 2005 and comparing to analytical data of 2002, the water section of Cai Tau river at the power plant has signal of organic pollution due to the wastewater of Ngoc Sinh seafood processing plant and Cai Tau residential area.

Riverbed topography of Cai Tau river is rather flat, sediment is fine silt, black-brown mixing with decayed leaves and roots. Before dredging, depth of this river is about 2.5-3m and after dredging to expand port area, the depth of this section will be 4m.

At present, left bank of Cai Tau River section is no vegetation because of clearance and consolidation process at two power plants. In the future, this river bank will be concreted for anti-erosion;

Right bank of the Cai Tau river section is the Cai Tau residence center with a lot of boats. All of domestic waste water discharge directly into Cai tau river causing bad smell;

300m far from Cai Tau confluence towards Ong Doc river, Tac Thu ship dock has already finished and being testing process.



33350.7

3336 0.7

Site 1 33371725

0.11726

0.11727

0.1

Site 2 1728 3341

0.13342 3343

0.1 3365Site 0 3343 0.25 Distance between two transects (km)

3365 0.25

33660.25

Site 3 33673368

0.253369

0.2533701729

0.317303344

0.43345

0.4

Site 4 33463347

0.6 3348

0.633491731

0.71732

0.71733

0.717341735

0.35 Ca M au city1736

0.35

Intake 2m 3

Transect name infront of water Transect name rearwards of water taking site

Tac Thu Sluice

To Thoi Binh

Cai Tau Confluence

NOTE

W ater intake site

W astewater discharge site

W est sea directionTransect

nam eDistance

(km)

Ca M au power plant 1 area

Fig 4.1 DIAGRAME OF COOLING WATER INTAKE SITE, DISCHARGE SITES IN OPTIONS AND TRANSECT SITES

Note: To distinguish current regime or concentration before and after discharged site as well as intake site, in calculation schema prior and behind section will be named. At Cai Tau confluence or Tac Thu confluence to Ca Mau will also such section to distinguish dividing of current. In data tables, these points are marked by red circle ( ), section name is recorded by ordinal number as Figure 4.1. Tac Thu sluice is symbolized as blue cross ( ). Location of intake and discharge sites is symbolized as follows:



− VT0: Cooling water intake site for both CM1 & CM2 power plants - VT 1: Cooling water discharge site of CM1 power plant - VT 2: Industrial discharge site of both CM1 & CM2 power plants - VT 3: Cooling water discharge site of CM2 power plant at Fertilizer port - option 2 - VT4: Cooling water discharge site of CM2 power plant at Cai Tau confluence - option 1 Modeling Results 1. Variation of water current of Cai Tau river and Ong Doc river due to cooling water

intake and wastewater discharge The project area is controlled by two tidal regimes, semi-diurnal tidal regime from East Sea with amplitude of 3m from Ganh Hao, My Thanh rivers, and diurnal tidal regime of West sea with amplitude of 1-1.5m from Ong Doc and Cai Lon river. Current direction often changes one or two times within 30 minutes/time during a day. When tidal turning, current is almost zero (stand current). This characteristic will make discharged effluents not yet diluted then turned oppositely.

In case of Tac Thu sluice is opened When existing both CM and CM2 power plants at this area, the regular intake of cooling water with flow rate of 2m3/s from Cai Tau river and discharge cooling water as well as treated industrial wastewater into Cai Tau river will change the current on this river system. When both power plants come into operation, average flow rate of Cai Tau – Ong Doc river as opening Tac Thu sluice, is given in Table 4.9 and Figure 4.2.

Table 4.9 AVERAGE FLOW OF CAI TAU – ONG DOC RIVER (m3/s) IN THE DRY SEASON WHEN THE POWER PLANTS COME INTO OPERATION

(in case of opening Tac Thu sluice)

Transect’s name

Qaver. P0 Qaver. P1 Qaver. P2 Position

3335 21 23.2 24.5 3336 21 23.2 24.5 3337 21 23.2 24.5 1725 21 23.6 24.5

VT1

1726 21 23.6 24.5 1727 21 23.6 24.5 1728 21 23.6 24.5 3341 21 23.6 24.5

VT2

3342 21 23.6 24.5 3343 21 23.6 24.5 3365 21 21.6 22.5

Taking 2m3/s VT0

3366 21 21.6 22.5 3367 21 21.6 22.5 3368 21 22 22.5

VT3

3369 21 22 22.5 3370 21 22 22.5 1729 13.2 14.4 14.7

Cai Tau confluence VT4

1730 13.2 14.4 14.7 3344 13.2 14.4 14.7

Tac Thu sluice

3345 13.2 14.4 14.7 3346 13.2 14.4 14.7 3347 13.2 14.4 14.7



3348 13.2 14.4 15.5 3349 13.2 14.4 15.5 1731 13.2 14.4 15.5 1732 13.2 14.4 15.5 1733 13.2 14.4 15.5 1734 13.2 14.4 15.5 1735 25.7 26.2 27.1

T-junction to Ca Mau city

1736 25.7 26.2 27.1 1737 25.7 26.2 27.1 3350 25.7 26.2 27.1 3351 25.7 26.2 27.1 3352 25.7 26.2 27.1

12

14

16

18

20

22

24

26

28

3335

3337

1726

1728

3342

3365

3367

3369

1729

3344

3346

3348

1731

1733

1735

1737

3351

Transection's name

Q (m

3/s)

P0 P1 P2

Taking 2m3/s

Cai Tau river sectionTac Thu river section

Figure 4.2 AVERAGE FLOW ALONG CAI TAU – ONG DOC RIVER IN CASE OF WITHOUT AND WITH TWO POWER PLANTS – AS OPENING TAC THU SLUICE

Calculation results in the dry season (from November to April) in Table 4.9 and Figure 4.2, in the case of Tac Thu opening show that:

- Regular cooling water intake of 2m3/s for both CM1 and CM2 power plants will increase the water volume from Cai Tau river toward Ong Doc river which makes increasing flow. For example, at cooling water intake site VT0, average flow increases from 0.6 to1.5 m3/s and at cooling water discharge (VT1) and industrial wastewater discharge (VT2) of the CM1 and CM2 power plants increases from 2.2 to 3.5m3/s.

- Current velocity of the Cai Tau river section from cooling water discharge site of CM1 power plant (VT1) to Cai Tau confluence is higher than the current velocity from Cai Tau confluence to Ong Doc – Tac Thu confluence.

- The tendency of average flow is from Ca Mau flowing to Ong Doc river and from Cai Tau confluence flowing to the sea via Ong Doc river.



In case of Tac Thu sluice is closed Average flow of Cai Tau – Ong Doc river is given in Table 4.10 and Figure 4.3.

Table 4.10 AVERAGE FLOW RATE OF CAI TAU – ONG DOC RIVER (m3/s) IN THE DRY

SEASON WHEN POWER PLANTS COME INTO OPERATION (In case of Tac Thu sluice is closed)

Transect’s name Qaver.P0

Qaver.P1 Qaver.P2 Position

3335 23.3 20.6 20.2 3336 23.3 20.6 20.2 3337 23.3 20.6 20.2 1725 23.3 21 20.6

VT1

1726 23.3 21 20.6 1727 23.3 21 20.6 1728 23.3 21 20.6

3341 23.3 21 20.6 VT2

3342 23.3 21 20.6 3343 23.3 21 20.6 3365 23.3 19 18.6

taking 2m3/s VT0

3366 23.3 19 18.6 3367 23.3 19 18.6 3368 23.3 19 19

VT3

3369 23.3 19 19 3370 23.3 19 19 1729 0 0 0


1730 0 0 0 3344 0 0 0

Tac Thu Sluice

3345 0 0 0 3346 0 0 0 3347 0 0 0 3348 0 0 0 3349 0 0 0 1731 0 0 0 1732 0 0 0 1733 0 0 0 1734 0 0 0 1735 20.6 19.9 19.8

Confluence to Ca Mau city

1736 20.6 19.9 19.8 1737 20.6 19.9 19.8 3350 20.6 19.9 19.8 3351 20.6 19.9 19.8 3352 20.6 19.9 19.8



Fig.4.3 AVERAGE FLOW RATE ALONG CAI TAU – ONG DOC RIVER WITHOUT AND

WITH TWO POWER PLANTS (in case of closing Tac Thu sluice) From above results in case of closing Tac Thu sluice, it can be drawn as follows:

− When Tac Thu sluice is closed, maximum down flow and back flow current on the Cai Tau river much decrease in comparing as sluice opening. Immediate current in Ong Doc river section from Cai Tau confluence to Tac Thu confluence is very small and average current is mostly zero.

12

14

16

18

20

22

2433

35

3337

1726

1728

3342

3365

3367

3369

1729

3344

3346

3348

1731

1733

1735

1737

3351

Transect's name along the river

Q (m

3/s)

P0 P1 P2

Taking 2m3/s

Cai Tau river section Tac Thu river section

(Q>0 from Cai Tau-Tac Thu-Ong Doc river to the sea)

− At the cooling water intake site (VT0), average flow reduces from 2.3 to 2.7m3/s. At the cooling water discharge site of CM1 power plant (VT1) and the CM2 power plant (VT3), the average flow decreases from 4.3 – 4.7m3/s.

− The continuous cooling water intake of 2m3/s for both CM1 and CM2 power plants will make the water level reduced from 1 to 6cm.

− Although the current on Cai Tau and Ong Doc rivers decreases in comparing with case of opening sluice but it is still higher than flow on the downstream river from Tac Thu sluice.

2. Heat pollution on Cai Tau river due to the cooling water discharge

After the heat exchanging process at cooling tower, the used cooling water (CW) will be regularly discharged into Cai Tau river with flow rate of 0.4m3/s (1,440m3/h) with the discharged temperature in normal operation condition at 35oC. In case of gas tail incident (rarely happen), cooling water discharge temperature is highest of 40oC. Because the cooling water is not taken place to technological process, but it only used for heat exchange, so it is classified as a clean wastewater (not polluted by pollutants and plant’s chemical). In practical, cooling water at the discharge end in CM2 power plant will be routed via discharged pipeline with 1,038m length to Cai Tau river, in which 250m is closed pipeline and 788m open pipeline. Therefore the temperature at the outlet to Cai Tau river will reduce considerably and completely meet Vietnamese Standard TCVN 5945:1995. However, due to high quantity of regular cooling water discharged into the river that is controlled by both East and West sea tide, so heat impact on environment has to be also assessed in detail.



In order to assess the heat impact of cooling water on the Cai Tau’s aquatic environment and its vicinity, RDCPSE has used cooling water dispersion model running for two following options in normal case (35oC) and in emergency one (40oC).

- Option 1 (P1): cooling water discharged to Cai Tau confluence (VT4) - Option 2 (P2): cooling water discharged to Port area (VT3)

Input data of Modeling During calculating, it is necessary to consider all of the accumulative effects between CM1 & CM2 power plants as mentioned in Table 4.8 including intake and discharged cooling water effluents and Tac Thu sluice are shut down in the dry season. Input data of cooling water dispersion modeling is listed as follows:

- Average temperature of river at the discharge site is 28oC - Cooling water temperature at outlet is 35oC in normal operation - Cooling water temperature at outlet is 40oC in tail gas incident - Discharge flow rate of 0.4m3/s - Average atmosphere temperature in Ca Mau area is 30oC - Average wind speed in Ca Mau area is 1.5m/s - Relative humidity in Ca Mau area is 80% - Temperature’s diffusion coefficient is 30m2/s − Heat exchange coefficient depending on Hydro meteorological condition and referred

from Wada chart: Qo=530cal/m2/s and Q1=17cal/m2/s.oC [19] - Calories at heat source to the river are calculated by formula: W=ρ.Cρ.q.Ts with q

(discharged flow rate), ρ (water density), Ts (discharged temperature), Cρ (heat capacity of water) [Appendix 3].

- Discharge mode: horizontal discharge to the surface layer through discharged outlet far about 15m from riverbank.

Modeling results

In case of discharged cooling water temperature of 35oC The detail result of average and maximum temperature increase along Cai Tau - Ong Doc river in two discharged options with discharged temperature of 35oC is shown in Table 4.11 and Figures 4.4 & 4.5.

Table 4.11 AVERAGE AND MAXIMUM TEMPERATURE INCREASE ALONG CAI TAU - ONG DOC RIVER BY 2 DISCHARGED OPTIONS IN 6 MONTHS OF

DRY SEASON - DISCHARGED TEMPERATURE OF 35oC

Transect name

TmaxP1 TmaxP2 Taver,P1 Taver,P2 Distance (km) Site

3335 2.96 3.03 0.65 0.66 0 3336 3.14 3.17 0.87 0.86 0.7 3337 3.50 3.50 1.09 1.07 1.4 1725 3.50 3.50 1.11 1.10 1.4

VT1

1726 3.44 3.44 1.04 1.04 1.5 1727 3.37 3.37 0.98 0.98 1.6 1728 3.31 3.36 0.90 0.92 1.7 3341 3.31 3.36 0.91 0.92 1.7

VT2

3342 3.28 3.34 0.89 0.92 1.8 3343 3.28 3.34 0.87 0.92 1.9 3365 3.28 3.34 0.87 0.91 1.9

Take 2m3/s VT0

3366 3.18 3.42 0.87 0.91 2.15



3367 3.16 3.50 0.88 0.98 2.40 3368 3.16 3.50 0.88 1.05 2.40

VT3

3369 3.33 3.29 1.01 1.05 2.65 3370 3.50 3.26 1.10 0.46 2.9 1729 3.50 3.26 1.10 0.44 2.9


1730 0.01 0 0 0 3.2 3344 0.07 0.08 0.05 0.06 3.2

Tac Thu sluice

3345 0.07 0.08 0.05 0.06 3.6 3346 0.07 0.08 0.05 0.06 4 3347 0.07 0.08 0.05 0.06 4 3348 0.08 0.09 0.06 0.06 4.6 3349 0.14 0.13 0.06 0.06 5.2 1731 0.14 0.13 0.06 0.06 5.2 1732 0.27 0.26 0.06 0.06 5.9 1733 0.42 0.41 0.07 0.07 6.3 1734 0.66 0.65 0.07 0.07 7 1735 0.66 0.65 0.07 0.07 7

Confluence to Ca Mau

1736 0.64 0.63 0.07 0.07 - 1737 0.64 0.63 0.07 0.07 - 3350 0.64 0.63 0.07 0.07 - 3351 0.62 0.61 0.07 0.07 -

Note: Distance (km) is calculated from transect 3335 to Tac Thu confluence to Ca Mau. At discharge site will have closed prior and behind transects so distance at this site is considered as zero. When current is conversed (v=0), temperature reaches maximum value.

Fig 4.4 HIGHEST TEMPERATURE INCREASE BY DISCHARGED OPTION DURING 6 DRY MONTHS (DISCHARGED TEMPERATURE OF

35oC)

0

0.5

1

1.5

2

2.5

3

3.5

4

0Km 0.7

1.4

1.4

1.5

1.6

1.7

1.7

1.8

1.9

1.9

2.15 2.4

2.4

2.65 2.9

2.9

3.2

3.2

3.6 4 4

4.6

5.2

5.2

5.9

6.3 7

Distance (Km)

ToC

Tmax P1 Tmax P3

CW discharge site-CM1 CW discharged site CM2(P2) CW discharged site CM2 (P1)



Fig. 4.5 AVERAGE TEMPERATURE INCREASE BY DISCHARGED OPTION DURING 6 DRY MONTHS (DISCHARGED TEMPERATURE OF 35oC)

0

0.2

0.4

0.6

0.8

1

1.20K

m 1.4

1.5

1.7

1.8

1.9

2.4

2.65 2.

9

3.2 4

4.6

5.2

6.3

Distance (Km)

ToC

TbqP1 TbqP3

CW discharge site-CM1 CW discharge site- CM2 (P2) CW discharge site- CM2 (P1)

The above results show that: Regular cooling water discharge of the two power plants into Cai Tau river will cause

light increase of water environment’s temperature on Cai Tau river section from cooling water discharge site of CM1 power plant (VT1) to Cai Tau confluence (VT4) in the distance of about 1.5km. This will cause insignificant impact on water quality of Cai Tau and Ong Doc rivers.

At the discharge site, the average temperature’s increases of both discharge option 1

and 2 are similar at 1.1oC. At cooling water intake site, the temperature difference decreases about 0.87 - 0.91oC. From downstream of Tac Thu sluice following to Ong Doc river, temperature difference according to two options is only 0.05oC – 0.07oC.

At the stand tide (v=0), the maximum temperature increase at the discharge sites vary in

the range of 3.26-3.5oC. At the cooling water intake site (VT0), far from cooling water discharge of CM1 (VT1) and CM2 (VT3) is about 500m, maximum temperature increase is about 3.28oC for option 1 and 3.34oC for option 2. Because Cai Tau river is controlled by west sea and east sea tide, so in a day, there are at least one tidal change (diurnal tide) and maximum 2 tidal changes (semi-diurnal tide), each tidal changing time lasts only in 30 minutes. Thus, the time of high temperature lasts in the range of 30 minute to 1 hour/day. Furthermore, highest temperature increase at stand tide is still within in seasonal variation so it will cause insignificant impact on cooling water intake for two plants and water supply for aquaculture along the Cai Tau river.

Comparing the two options, temperature increase between them is similar.



In case of discharged cooling water temperature of 40oC In case of gas tail incident, calculation result of average and maximum temperature increase along Cai Tau - Ong Doc river in two cooling water discharge options with discharged temperature of 40oC in six dry months are summarized in Table 4.12 and Figure 4.6 &4.7.

Table 4.12 AVERAGE AND MAXIMUM TEMPERATURE INCREASE ALONG CAI TAU-ONG DOC RIVER

Section name Taver,P1 Taver,P2 TmaxP1 TmaxP2 Distance (km) Site 3335 1.64 1.42 7.61 7.8 0 3336 2.13 1.86 8.08 8.16 0.7 3337 2.66 2.34 9 9 1.4

1725 2.73 2.42 9 9 1.4

VT1

1726 2.56 2.29 8.85 8.86 1.5 1727 2.38 2.16 8.66 8.59 1.6 1728 2.21 2.03 8.52 8.47 1.7

3341 2.21 2.03 8.5 8.46 1.7 VT2

3342 2.17 2.02 8.44 8.41 1.8 3343 2.13 2.01 8.43 8.46 1.9 3365 2.13 2.01 8.43 8.46 1.9

intake 2m3/s VT0

3366 2.13 2.16 8.15 8.7 2.15 3367 2.13 2.32 8.11 9 2.40 3368 2.14 2.35 8.11 9 2.40

VT3

3369 2.46 1.57 8.55 8.45 2.65 3370 2.67 1.06 9 8.37 2.9 1729 2.66 1.03 9 8.36 2.9


1730 0.01 0 0.02 0.01 3.2 3344 0.13 0.13 0.18 0.18 3.2

Tac Thu sluice

3345 0.13 0.13 0.18 0.18 3.6 3346 0.13 0.13 0.19 0.19 4 3347 0.13 0.13 0.19 0.19 4 3348 0.14 0.14 0.22 0.21 4.6 3349 0.15 0.14 0.33 0.32 5.2 1731 0.15 0.14 0.33 0.32 5.2 1732 0.16 0.15 0.66 0.64 5.9 1733 0.17 0.15 1.04 1.02 6.3 1734 0.17 0.16 1.62 1.60 7 1735 0.18 0.16 1.62 1.6 7


1736 0.18 0.16 1.59 1.56 - 1737 0.18 0.16 1.58 1.54 - 3350 0.18 0.16 1.58 1.54 - 3351 0.18 0.17 1.53 1.5 -



0

0.5

1

1.5

2

2.5

3

3335

3336

3337

1725

1726

1727

1728

3341

3342

3343

3365

3366

3367

3368

3369

3370

1729

1730

3344

3345

3346

3347

3348

3349

1731

1732

1733

1734

1735

1736

1737

3350

3351

3352

Location along river

tem

pera

ture

incr

ease

ToC

P2 P1

Cai Tau river Tac Thu - Song Doc river

Fig. 4.6 AVERAGE TEMPERATURE INCREASE ALONG THE RIVER IN TWO OPTIONS

IN SIX DRY MONTHS – DISCHARGED TEMPERATURE OF 40oC

0

1

2

3

4

5

6

7

8

9

10

3335

3337

1726

1728

3342

3365

3367

3369

1729

3344

3346

3348

1731

1733

1735

1737

3351

Location along river

Tem

pera

ture

incr

ease

ToC

P2 P1

Cai Tau River Ong Doc River

Fig. 4.7 MAXIMUM TEMPERATURE INCREASE ALONG THE RIVER IN TWO OPTIONS

IN SIX DRY MONTHS – DISCHARGED TEMPERATURE OF 40oC Above results show that:

In case of tail gas incident, cooling water discharge of CM1 & CM2 power plants to Cai Tau river will increase significantly temperature of water environment on Cai Tau river section from cooling water discharged point of CM1 power plant to Cai Tau confluence (1.5km). However, cooling water temperature at outlet still meets Vietnamese

≤40oC. environmental standard of

At discharge site, average temperature increases about 2.6oC in option 1 (VT4) and 2.3oC

in option 2 (VT3). At cooling water intake, temperature difference is about 2.1oC

following option 1 and 2.0oC in option 2. From downstream of Tac Thu sluice via Ong Doc river, temperature only about 0.13-0.19oC. increase of two discharged options are



At the stand tide (v=0), maximum temperature increase are rather highly (8-9oC) due to discharge water is almost no diluted. At this time, highest temperature increase at cooling water intake is about 8.4oC that cause directly impact on cooling water intake for 2 plants. However, in case of tail gas incident occured, the plant only operates at this regime within very short period. Furthermore, period for high temperature increase lasts no longer only about 30 minutes to 1 hour per day.

3. Impact of industrial wastewater Industrial wastewater created during the the CM2 power plant’s operation, as well as the CM1 power plant, includes: − Water from heat recovery steam generator: continuous discharge with regular average

flow is about 4.6m3/hour at 100oC. Blow down water from the heat recovery steam generator is demineralizing water containing following components: + Phosphate: 6 mg/l + Ammoniac: 5 mg/l + Hydrazine: 2 mg/l + EC: 3 - 5 μS

The released water from blow down boiler with flow rate of 4.6m3/h is routed to cooling water tower to mixed with cooling water (1200m3/h) and then discharged to Cai Tau river. Basing on calculation, concentration of ion phosphate in boiler blow down is < 3mg/l and concentration of ion phosphate in cooling water discharge after mixing is < 0.012mg/l. According to the Industrial wastewater standard as discharge to the river that used for aqua-product protection purpose (TCVN 6984:2001), allowable limit for total phosphor content is 5mg/l. Thus, concentration of ion phosphate in cooling water discharged to Cai Tau river is very small and it will not cause any impacts on water quality of Cai Tau river.

− Other wastewaters: including regular and irregular industrial wastewater. Flow rate of these effluents are summarized in Table 4.13.

Table 4.13 INDUSTRIAL WASTEWATER TYPES OF THE CM2 POWER PLANT

Discharged flow rate (m3/h) Sources Normal Maximum

Regular wastewater − Wastewater from RO of demineralization system 10 10 − Condensing water from gas supplying unit 0.01 001 − Wastewater from area of generator of GT 0 2 − Wastewater from area of generator of ST 0 72 − Wastewater from boiler 0 2 − Wastewater from transformer station 0 36 − Wastewater from DO storage tanker 0 10 − Wastewater from gas compressor 0.1 0.1 − Wastewater from septic tank 1.7 3 Total 11.81

(# 0.0033 m3/s) 135.11

(# 0.0375m3/s) The plant’s operation also generates an irregular wastewater (3-5 years/time) mainly from de-mineralizing water system, wastewater from the heat recovery boiler, transformer area, generator and diesel tank area. Estimated irregular wastewater is about 374m3/h. Other regular and irregular industrial wastewaters containing a large quantity of suspended solid, lubricant oil, and low pH will be routed to share treatment system located in CM1 Power plant. Oily wastewater will be separated oil; others will be leaded to preliminary sedimentation tank. Pre-treated wastewater will be directed into common tank and treated



(neutralizing, separating, etc.). Treated wastewater met Vietnamese Standard TCVN 6984:2001 will be discharged together with industrial wastewater of CM1 power plant to Cai Tau river with discharged flow rate of 0.008m3/s at VT2 (coordinate X= 102231.527; Y= 397024.993). To evaluate effluence of industrial wastewater discharge of both CM1 & CM2 power plants by organic pollution dispersion modeling on river/canal system during 6 months of the dry season and in case of closing TacThu sluice, input data include: − Cai Tau river water is considered as rather clean with BOD of about 5mg/l; − Industrial wastewater after treatment met Vietnamese standard is considered as light

pollution with discharged BOD of about 15mg/l; − Discharged wastewater flow rate of 0.008m3/s; − Discharge mode: horizontal discharge to the drainage closing to riverbank. According to modeling results, average and maximum BOD content along Cai Tau – Ong Doc river following location and transect is summarized in Table 4.14.

Table 4.14 THE AVERAGE BOD (mg/l) ALONG CAI TAU – ONG DOC RIVER WHEN

BOTH POWER PLANTS DISCHARGE INTO CAI TAU RIVER

Transect’s name

BOD (baseline) (mg/l)

Average BOD (mg/l)

BOD max (mg/l)

Distance (km) Site

3335 5 5.07 5.74 0 3336 5 5.07 6.19 0.7 3337 5 5.06 6.95 1.4 1725 5 5.07 7.04 1.4

VT1

1726 5 5.15 9.30 1.5 1727 5 5.23 14.73 1.6 1728 5 5.30 15 1.7

3341 5 5.30 15 1.7 VT2

3342 5 5.22 12.89 1.8 3343 5 5.15 9.48 1.9 3365 5 5.13 9.48 1.9

intake 2m3/s VT0

3366 5 5.09 7.54 2.15 3367 5 5.05 6.60 2.40 3368 5 5.04 6.35 2.40

VT3

3369 5 5.04 5.86 2.65 3370 5 5.03 5.77 2.9 1729 5 5.03 5.77 2.9


1730 5 5 5.01 3.2 3344 5 5 5.01 3.2

Tac Thu sluice

3345 5 5 5.01 3.6 3346 5 5 5.01 4 3347 5 5 5.01 4 3348 5 5 5.01 4.6 3349 5 5 5.01 5.2 1731 5 5 5.01 5.2 1732 5 5 5.03 5.9 1733 5 5.01 5.04 6.3 1734 5 5.01 5.06 7 1735 5 5.01 5.06 7


1736 5 5.01 5.06 - 1737 5 5.01 5.06 - 3350 5 5.01 5.06 - 3351 5 5.01 5.06 -



The dispersion modeling result of wastewater shows that, the average BOD at discharge site (VT2) of two power plants only differs with baseline BOD of river of 0.3mg/l. The maximum BOD content at discharge site is 15mg/l due to stand tide (v=0) it is not diluted. From Cai Tau confluence down to Ong Doc river, BOD content is approximate baseline BOD of river is about 5 mg/l. At water intake site, average BOD (5.15mg/l) increases insignificantly in comparison with baseline BOD of Cai Tau river of 5 mg/l. Generally, the discharge treated industrial wastewater of CM1 and CM2 power plants will cause insignificant on the water quality of Cai Tau - Ong Doc river due to very small discharged volume. 4. Domestic wastewater During the operation phase, number of the working staff at the Ca Mau 2 power plant is about 150 persons. According to the discharge criteria from Vietnam Institute of Hygiene Public health, the daily domestic wastewater volume is about 25m3. Domestic wastewater will be treated in septic tank system and then routed to share treatment system of both plants before discharging to Cai Tau river. Due to very small amount of wastewater so it is almost no impact on water quality of Cai Tau river. 5. Run-off water The run-off water from different areas will be also collected in floor water drainage system. Run off water through oil tank area, outdoor transformer, equipment washing water, rainy water drainage in initial rain (about 5 minutes to heavy rain) can be oily. That will be treated at oily separation system and then routed to common treatment tank of the plant. In case heavy rain, run off water is supposed clean and discharge into Cai Tau river. Rain water discharge system in the plant is devided into many areas. Generally, runoff water will not cause any affect to surface water quality. 4.2.2.3 Impacts on soil quality The operation of the Ca Mau 2 power plant will impact to soil quality and sediment due to oil spill or oil/chemical leak and other solidwaste. 1. Effects due to DO and chemical storage in the plant For the productive demand, the plant has to store a big quantity of chemicals for operation, and maintainance for 12 months. Similar to CM1 ower plant 1, CM2 power plant 2 will use some normal inorganic substances belonging to list of non-toxic or less toxic chemicals. Almost subtances (H2SO4, HCl, NaOH, NaCl, Na2CO3, Na2SO3, Al2(SO4)3, FeSO4, …) are available in Vietnam and transported from Ho Chi Minh City. At the plant, acid H2SO4 is stored with volume of 50m3 and other chemicals is about 5 m3. The regular use of strong acid or alkaline as well as a big quatity of chemicals in the plant’s area might cause spillage or leakage due to mistake or fault of the workers. For these spillages, unless managed or suitably collected, they will pollute the groundwater and the run-off water. Although the plant surface has been cemented, chemical tanks in the area wilth embankment and anti-absorbent ground, but the soil environment might be polluted by strong alkaline or acid leakage. In case of the natural gas supplying is interrupted, the plant will have to use alternative DO fuel. Diesel oil is stored in two tanks with volume of 5,000m3/tank. These are specific tanks (double hulls) located on the concrete foundation and having bunded around, that can contain 110% tank volume. Run-off water or leakage oil in the bund will be directed to oil treatment system. Therefore, the spillage effect in the plant is considered as minor level. It is necessary to minimise the oil spilll risk while unloading from ship to the plant’s tanks, because the plant is located closed to T21 Canal, connecting to Cai Tau Confluence, so the environmental risk is rather high.



2. Effect of solid waste The CM2 power plant operation will generate a quantity of solid waste from some following sources: − Industrial waste: including packing, oily rag, and little oil, chemical from normal activities

and maintenance of the plant. The estimated quantity of industrial is about 0.5 – 1tone/day;

− Sludge from the wastewater treatment: including residual sludge from the wastewater treatment, as well as from the cooling tower;

− Residue oily waste: generated from the oily separation system; − Domestic waste: in operation phase, about 150 employees will work in the Ca Mau

Power plant 2. Estimated domestic waste is about 0.85kg/person/day and food-waste of 0.58kg/person/day. Therefore, the waste quantity of the power plant is about 200 kg/day.

Unless the waste is well managed or discharged at the right place, they will cause significant effects to soil/groundwater quality. Project owner will sign contract with the Ca Mau Environment and Urban Company in order to collect and treat this waste. In general, the solid waste from power plant activity is minor and less toxic, so the effect on the soil environment and ground water is insignificant. 4.2.3 Impacts on Biological environment Like the CM1 power plant, normal operation of the CM2 Power plant will not cause considerable effect on the terrestrial environment. The normal operation will not cause significant effects to the surrounding vegetation where is mainly rice field. The Vo Doi specific forest is considered as the nearest place from the project area with distance of 8 –10 km. Therefore, the operation might only reduce the number of the birds, coming here for food. The considerable impact on the biological environment from the plant operation is on the aquatic environment due to the cooling water intake. The added cooling water for the CM2 power plant is 1,440 m3/hour, will impact on the aquatic ecosystem as follows:

− Effect of cooling water intake: Although the mouth of cooling water suction pipe is installed a bar-screen system with different hole sizes from 20cm, fixed net hole of 2cm and spin net with hole size less than 1cm. But the cooling water suction with velocity of 0.3m/s could also entrain a number of organisms including zooplankton, phytoplankton, fish egg, larvae and young fish/prawn. It is impossible to forecast the exact influence of the cooling system to pulled organisms, but dead rate will be high, especially fish eggs;

− Effect of cooling wastewater discharge: according to cooling water dispersion modeling result in the case of normal operation with cooling water discharge temperature of 35oC, the average temperature at discharge point will increase about 1.1oC. The slight temperature increase will not cause directly impact on aquatic ecosystem. In case of tail gas incident, the increment of average temperature will be about 2.2 – 2.4oC and maximum temperature will be about 8 - 9oC. The temperature increment will cause local thermal pollution around discharge points and increase the metabolism, the fast growing of some algae (for example green alga at 30 – 35oC and blue alga at 35 – 40oC) and cause effects on aquatic organism because the blue alga is a poor food.

4.3 DECOMMISSION PHASE According to the basic design, the CM2 power plant will operate in 25 years. At the point of the report reparation, there isn’t any detailed plan for the decommission phase. There are two options might apply in the decommission phase:



1. Partly removal: only some equipment units will be dismounted and moved away, other works can be preserved to reused for other purposes;

2. Wholy removal: equipment units will be dismounted and moved away. Main environmental impact sources mainly concern with the commissioning and transporting the plant and utilities. These activities will disturb the project area and obstruct other activities at its vicinities. In addition, the decommissining of the Plant’s productive workshops will generate a quantity of hazardous and non-hazardous waste including fuel oil, lubricant scrap from used equipment, etc. Moreover, there are also domestic waste, wastewater generated from the plant area.

Option 1: In case of partly removal, some following impacts can happen: - Disturb the soil environment at the project area; - Disturb the natural condition and environment at the plant area; - Impact on the surrounding areas due to noise, dust, shining,.etc. - Disturb all roads due to transportation..etc. - Discharge debris of tanks, pipes, bricks..etc. - Transporting filling material for gully before covering. - Polluting soil and sediment in and around the project area depending on the future used

purpose. Option 2: In case of wholy transfer, environmental impact is similar to the above case, however the impact level will be higher. In general, environmental impact in this phase is similar to the one in the construction/commissining phase but it occurs in a short time and slighter. Main environmental impacts from two options like above mention as follows: 4.3.1 Impact on physical environment 1. Air quality Decommission process of heat and electric mechanism equipment, gas pipeline system and ultility equipment will generate a considerable quantity of residual hydrocarbon and chemical fume in the equipment units and dust will pollute the atmospheric environment. However, the decommission activities only occur in a short time (approximate 6 months) so the environment impact is considered as temporary moderate level. 2. Water quality The decomission of equipment units and chemical, fuel storage tanks can leak chemicals and other pollutants into the adjacent river (new canal and Cai Tau river). Leakage of strong acid or alkaline chemicals will cause suddend reduction of increment of pH in the water column. In case of fuel oil leakage to water environment,the impact level is considered as from minor to major depending on the leaked fuel volume. Futhermore, domestic waste genrated in this phase may cause pollution on water environment due to increasing of organic matter content. 3. Soil quaity A few waste will be remained after commission. If not well managed, it will pollute the soil from minor to major level in the project area. In case of removing and disconnecting the fuel and acid/alkaline storage tanks, that will pollute the soil due to leakage or spillage. If the fuel pipeline is left, it can longterm pollute the soil environment because of metal erosion and decomposition.



4.3.2 Impact on the biological environment Decommission activities will impact on the aquatic and terrestrial biological environment. Normally, the impact during the decommission phase on the biological is lower than one during the construction/commission phase. 4.4 IMPACT ON THE SOCIO-ECONOMIC ENVIRONMENT The Ca Mau Power plant construction will cause positive and negative impact on socio-economical environment of Khanh An cummune in particular and Ca Mau Province in general. 4.4.1 Impact on popualation and labour force distributtion Movement and resettlement

All works for people migration and site clearance of Ca Mau Integrated Gas – Power - Fertilizer area had been completed in 2001 by Ca Mau People Committee. Petrovietnam had paid satisfactorily compensation for local people and finished since 2001. However, in order to stabilize the living condition for local people in initial years, Petrovietnam had supported the People Committee of Ca Mau Province and Khanh An Commune to build a temporary resettlement area with 300 fourth level houses at Cai Tau K1 prison land, about 300m from the power plant. Recently, ADB (capital loan bank for the project) inspected and interviewed local people who satisfy with compensation. The construction of new resettlement area is responsibility of Ca Mau People Committee. Until now, new resettlement area was planned (Fig. 3.4) and divided into plots, dug surrounding canal and built sluice to prevent fresh water for U Minh 3 farm.

Job and Training During the site filling up process (2002), the project had used 100% local manpower. The CM2 power plant implementation will need 1,500-2,000 workers in construction phase and about 258 workers experts in the operation phase. The training program for local workers also improves their knowledge/skill for the local labor force. However, the current educational background of workforce in Ca Mau is not high, about 21.7% of population had already learned/graduated from high school and only 7 - 8% of the population is skilled workforce. To meet a part of manpower demand of the plant, young labor force of the province could be employed and joined short or long-term trained to upgrade their skills to serve for the plant in the future. However, according to the complaint of Khanh An People Committee (Secretary of Khanh An commune, 22/12/2005) the priority norm of labor training for the Khanh An commune is not correspondent with the whole local current labor force. Thus, the execution of the power plant will cause the change of labor and occupation structure in long-term at the area and form a more skilled workforce. Besides, construction and development of the Ca Mau gas – power – fertilizer complex in general and the power plant in particular will push the development of other industrial branches such as transportation, services, commerce and industry. The project implementation will also impulse development of the local economy, enhance living standard and educational background of the local inhabitants. Increase of population density During the project implementation of the CM1 and CM2 power plants, there will be a number of immigrating labors coming from other provinces. That will increase the population density



in the area. The Khanh An population at 12/2005 is about 18,000 persons and according to site survey result, the existing population density in the project area is not high, they only concentrate along Cai Tau river. Therefore, construction of workforce camps during construction phase will not affect to local land fund. During construction phase, immigrating labors may cause some disturbances on the local life. These effect may be positive, enhance the diversity and plentifulness for the local culture. But, unless the local authority has a suitable management measure, the social evils may occur and that will disturb strongly on the local living due to the different lifestyle, habit and custom between the local residents and the project’s workforce. Several differences between the immigrant and the resident may happen in the construction phase. However, when the project comes into the operation phase, the project workforce will decrease (60%) and most technical staff will stay in the project’s building at Ca Mau city. Therefore, the effect of population increase is considered as minor level. 4.4.2 Impact on Agricultural development The power plant construction will permanently lose 10ha of agriculture land of Khanh An commune leading to the completely change of land use structure of hamlet 1 and effect directly on all moved households. But if it is generally considered the project area had already been changed land use purpose from agricultural to industrial land and land fund of Ca Mau is large, therefore, when the plant comes into the operation phase, impact level on the agricultural production is insignificant in comparison to benefits of the project for Ca Mau province in the future. 4.4.3 Impact on industrial development Up to now, Ca Mau province has several industrial branches such as aquatic product processing for export, rice grinding, medium and small mechanisms, ship building and repairing, foodstuff processing. The power plant execution will develop some industrial branches such as mechanism, construction, commercial service, etc. That contributes an important role in development of industrial production value in the area. The construction and development of the adjusting Ca Mau power plant will contribute in renewing and upgrading the whole infrastructure system of the area such as road system, enhancing power supplier, building wastewater drainage system, communication, commercial and service development, pushing up local industrial development and creating conditions for development of other projects in the area. The power plant 1 & 2 construction has used natural gas, pushing the development process of petroleum and energy industry. In addition, the development and activities of main industrial branches such power plant and other projects in Ca Mau industrial zone will create job for other small industrial branches to serve plant’s maintenance and operation. That has created many jobs and business investment chances for the local. 4.4.4 Impacts on transportation and infrastructure

Waterway traffic Ca Mau province has density waterway system cresting convenient condition for construction material and agricultural good transportation from Ca Mau to other provinces and vice versa. At present, Ca Mau has 4 interprovincial and 4 internal waterways. Those main waterways play key role of the strategy for economic construction and development of the province. During the site filling and consolidation for the project area, most sand and constructive material will be transported from Can Tho City to the plant (198km) by barge of 100 – 200tones/barge or large-barge of 80 tones/boat. Thus, estimated time for sand



transportation is about 16 months, the estimated number of boat/barges transporting over the waterway Can Tho – Trem river – Cai Tau river is about 100 barges/day and about 90-100 barges/day back and forth the Cai Tau area. During the construction and installation phase, cement will be transported from Kien Giang through Kien Luong – Xeo Ro – Trem – Cai Tau. Steel, super-weigh and super-size will be transported by barge of 300 tones following Can Tho – Ca Mau or Ho Chi Minh – Can Tho – Ca Mau. The estimated number of barges passing temporary port is about 15 – 20 barges/day during 18 – 24 months. The transporting of these materials will increase waterway traffic density over the main route (Trem River) and Cai Tau confluence, leading to the waterway and increment of collision risk on the canal/river system. The impact level is assessed at moderate level during the plant construction phase. During the operation phase, normal boat density is low at the DO unloading jetty (the highest is once per day) but that also lead to the increment of boat density and collision risk at port area.

Road traffic and infrastructure Beside the plant construction, PetroVietnam has cooperated with Ca Mau People Committee to construct infrastructure system for project activities and local resident such as the road system 14.5km long from Ca Mau city to the gas-power-fertilizer complex; installation of power supplied network, wastewater drainage and communication system etc. These activities will make the completely change of the area’s infrastructure from no internal road to interprovincial roads that give good condition to enhance living standard of local resident and create favorable condition for national and foreign investors into Ca Mau as well as pushing the industrialization and modernization of Ca Mau province in the future. 4.4.5 Impact on aquaculture and fishery According to the site survey result about the fishery existing status along Cai Tau river in Jan 2003 and Dec 2005 showed that almost agricultural households living along Cai Tau river (1-3km far from the plant) changed into ecological spawn 1 crop (in the dry season) since 2003 over their rice fields with low prawn productivity. Due to the cooling water from the revised power plant project (CM1 and CM2 power plants) is evaluated as clean wastewater, so the regular water intake of 2m3/s supplemented cooling water and discharge 0.8 m3/s directly into Cai Tau river of the two plants will not cause significant effects to Cai Tau river aquatic ecosystem, it just locally affects at discharge site (average temperature increasing of 1.1oC and maximum temperature of 3.5oC in comparison with the river’s current temperature (28oC)). Therefore, discharge cooling water will not cause any significant impact on the aquacultural activities along Cai Tau river. According to diluting wastewater model had showed at section 4.2.2.2, the discharging a treated wastewater (0.008m3/s) of both plants into Cai Tau river will cause insignificant impact on the aquacultural area due to the small wastewater and located out of the aquacultural area (Ong Doc river downstream) and ecological prawn area (Cai Tau river downstream). According to the evaluation of Ca Mau Fishery Department (June,2002 and December, 2005), catching fish activities on the river/canal surrounding the project (Ong Doc, Trem, Cai Tau rivers) is insignificant, about 6 fixed bottom nets at Ong Doc river and no net on Cai Tau and Trem river up to June, 2002. Therefore, the project operation will not cause any impact to fishing activities of local people. It is noted that before having presence of CM1 and CM2 power plants, the Cai Tau river’s water quality at the water intake point (VT0) in two measuring times: dry season 2002 and



dry season 2005 has tendency decreased due to discharging wastes from Cai Tau residential area and Ngoc Sinh aquatic product processing company on the K21 canal. 4.4.6 Impact on public health During the construction and installation phase, noise generated from operation of vehicles, and other construction equipment will cause noise that can affect to human health at construction site and adjacent area. The considerable emission of natural gas during the commission or commission will directly effect on the workers who work on site project area such as headache and dizzy. However, the gas venting is only carried out when the system is over-pressure and volume of venting gas is very small, so affected level on the workers who operate the plant is assessed as minor. Health care During the construction phase, temporary camp areas are supplied clean water and hygiene equipment. If wastewater is not adequately treated and directly discharged into the river, it will cause waterborne diseases such as cholera, dysentery, and typhoid. According to the project plan, there is a public health station for taking care the project’s employees and assisting in checking up health sickness for local resident in necessary. 4.4.7 Impact on culture and landscape Accompanying to the activities of Ca Mau 1 power plant, the activities of the power plant 2 at Cai Tau confluence - Khanh An commune will change the area’s landscape (view obstruction, noise, etc). The landscape will completely be changed from rural area to modern industrial zone. Light system from work units on the night that irritates to the local people and destroys the harmonious landscape of the pure rural countryside. Although Ca Mau province has a lot of protected areas with beautiful natural landscape, ecological tourist areas attracting visitors but project area is pure rural one and there is not any protected area or bird ground. Vo Doi specific forest is considered as the nearest place from the project area, but it is 8.5km far from the plant. All plant’s activities will not only cause effect on the special-use forest but also impulse the service activities for tourist development. In summary, construction and development of Ca Mau adjusting power plant will change the landscape because the plant’s activities and impact level is assessed as moderate during the project’s life times. 4.4.8 Impact on economy The revised Ca Mau power plant project is one of Vietnamese strategic projects with high efficiently natural gas utilization from southwest gas fields to produce and satisfy additional charge power demand in the future. The plant’s development has pushed up the area’s economic development and enhancing industrialization and modernization process of the country as well as increasing attraction of foreign investment at Ca Mau province. The project’s development is strongly pushing up, stimulating and exchange economic structure. It contributes an important socio-economic living enhance and securely keeping the politics-security for fatherland’s southwest area.



Section 5.

PRELIMINARY ENVIRONMENTAL RISK ASSESSMENT Environmental risks generated during implementation of the Ca Mau 1 power plant have been assessed primarily in the DEIA report for the Ca Mau 1 power plant. The additional construction of Ca Mau 2 power plant in the planned land for Ca Mau fertilizer plant of the Ca Mau gas - power fertilizer complex will increase risks of accident occurrence in the area as well as change environmental impacts when the accident occurs. Purpose of this section is to identify potential dangers and risks, which may occur during the implementation of the Ca Mau 2 power plant project, to qualitatively and quantitatively calculate risk possibility (with available data) as well as to identify effects on people, equipment and environment upon accident occurs in the Ca Mau 2 power plant. Here, changes in the environmental risks during the operation of the Ca Mau 1 power plant when the Ca Mau 2 power plant exists will also be considered. These assessments will help to have overall view on the project security in order to get appropriate mitigating measures in the project design and operation. More detail risk analysis and assessment about the project equipment and operation manual will be mentioned in separated reports during the project detail designing. 5.1 SOME HAZARDOUS PROPERTIES OF FUELS USED IN THE PLANT The main fuel of Ca Mau 2 power plant is natural gas exploited from Southwestern gas fields including from block PM3 in period 2003 - 2015 and then supplemented from Cai Nuoc field. The natural gases are composed mainly of alkanes from C1 to C5 with methane content of approximately 77.95% wt. Besides, the natural gases also contain 7.53% mol. of CO2 and almost no hydrogen sulfide. In case the natural gas supply is interrupted, the power plant will use stand-by fuel as imported diesel oil (DO) with maximum sulfur content of 0.5%wt. 1. Natural gas Some concerned hazardous properties of natural gas are:

- Natural gas exists in equipment under high pressure, so when leakage occurs, gas will be quickly escaped out and be difficult to control;

- Natural gas is flammable and form flammable mixture with oxygen when they are leaked into atmosphere. Limits of flammable mixture forming in the air of some alkanes are shown in Table 5.1.

When the flammable mixture is formed (flammable gas content in the air is in the range between low flammable limit (LFL) and upper flammable limit (ULF)), it may fire even with very little ignition (e.g. a electric spark). If firing process occurs inside a closed system, gas mixture will be heated and strongly expanded, inside pressure will be increased suddenly and lead to explosion, which is very dangerous for people and equipment in the affected area.



Table 5.1 LIMITS OF FLAMMABLE MIXTURE FORMING OF SOME ALKANES

Alkanes Low flammable level (LFL) (% in the air)

Upper flammable level (% in the air)

Methane (CH4) 5.0 15.0 Ethane (C2H6) 3.1 15.0 Propane (C3H8) 2.1 9.5 Butane (C4H10) 1.6 8.5 n-Hexane (C6H14) 1.2 7.4

Source: [16]

- Due to natural gases are heavier than the air, therefore once released, natural gases always drifts downwind and accumulates at lowest areas;

- Natural gas density is only about half of the water density, so it always floats on the water surface.

Methane

Methane is very flammable and creates colorless flame, secondary pollutants such as COx, THC and soot when be burned. Methane is assessed as low toxicity to creatures. However, people and animal will be dizzy or unconscious when respires a lot of methane. Very high concentration of methane in the air will lead to reduce oxygen content under respirable threshold and cause human and animal death. Methane content in the air of over 4.5% will cause suffocation due to lack of oxygen. Poison symptoms like convulsion, suffocation, pneumonia, lung abscess. When methane content in the air very high (over 40,000 mg/m3 equivalent to 5.6%) will decrease oxygen content to under respirable threshold and at content of over 60,000 mg/m3 (equivalent to 8.4%) will cause convulsion, respiratory and heart disorders, even lead to deaths of human and animals [17].

Carbon dioxide (CO2) Carbon dioxide is a colorless, odorless gas with a faint acid taste. CO2 is existed in the normal atmosphere at concentration varying from 0.03% to 0.06%. At concentration of 5%, CO2 in the atmosphere may cause shortness of breath and headache. CO2 with concentration of 10% in the air can produce unconsciousness for exposed people and lead to death from oxygen deficiency. CO2 does not give a warning of its present in an asphyxiating concentration and a person may unwittingly enter a confined space or descend into tank or vessel and be overcome before he becomes aware of the danger and can not make his escape. Concentration of CO2 in the air and correlative consequences are summarized in Table 5.2:

Table 5.2 CO2 CONTENT IN THE AIR AND CORRELATIVE CONSEQUENCES

Concentration of CO2 in the air (%) Consequence 0.15 May cause shortness of breath

0.3 - 0.6 Unable to work 3-6 Fatality danger

8 - 10 Headache, visual trouble, Asphyxiated 10 - 30 Immediate asphyxiated

35 Dead Source: [17]



♦

♦

♦

2. DO Diesel oil (DO) is a petroleum distillate belonging to medium fraction, light color and its main components include paraffin, olefin, naphthalene and hydrocarbons. DO has flash point over 60oC and boiling point in the range of 163 – 371oC. Aromatic hydrocarbon content is quite high, occupied 20 – 30% volume. That is one of the oil features causing toxic to the environment. Besides aromatic hydrocarbon, sulfur (0.1 – 0.5% wt.) and nitrogen are high toxic compounds, which need to be paid attention during environmental impact assessment and overcoming the accidental consequences. DO can be expected to spread on the water surface, evaporate, disperse, dissolve and dilute in first hours released into environment. DO is highly biodegradable (Hinchee et al, 1995a and 1995b). The water-soluble fraction is more readily available to microorganisms and it can be expected to degrade relatively rapidly following spillage into environment. Various environmental factors including temperature, oxygen concentration, nutrient availability and salinity of water environment will influence of the rate of degradation. DO is high toxic. Results of toxicity test on Artemia and Penaeus monodon (larvae) of commercial DO in Vietnamese market shown that, even at the oil concentration of 10 ppm, some responses showing the toxic effects of diesel oil on Penaeus monodon were recorded: decrease in swimming, 10% lethality. At the oil concentration of 80ppm, approximate 96% of Penaeus monodon died after 4 days exposing in polluted oil. 5.2 RESOURCE SENSITIVITY ASSESSMENT 5.2.1 Identify affected area The configuration of the CM2 power plant is the same as that one of the CM1 power plant, of which some equipment systems are used for both plants such as cooling water intake and discharge system, DO loading port. Therefore, in the operation of the Ca Mau 2 power plant, the most severe accidents that might occur include gas leakage (natural gas), fire/ explosion accidents if fire source exists, and DO spillage from DO tanks inside the plant. These accidents, especially fire/ explosion will cause severely effects to human, equipment and environments. Affected area when accident occurs depends on nature of each accident, environmental conditions, etc. Summary of affected areas are as follows:

Gas leakage: Leaked gases will disperse into the atmosphere and will affect mostly the plant area. Their effect may reach to the CM1 power plant area, Cai Tau prison area and surrounding residential areas within radius of 1000m toward to wind direction;

Fire and explosion: affected area mainly is the plant area. The affected area may be larger in terms of covered area of smoke and dust when accidents occurs (within radius of 1000m);

Oil spill: spilled oil from DO tanks in the CM2 power plant will generally affect insignificantly the environment due to the DO tanks are laid in the area surrounded by bunds. However, if oil spills during DO loading/ unloading, K21 canal and Cai Tau river may be affected.

Generally, in case that an accident happens, the Ca Mau 2 power plant area will be mostly affected and the area of Ca Mau 1 plant will also more or less be affected.



5.2.2 Sensitivity assessment of affected areas Environmental sensitivity can be determined by assessing biological resources, topography, geomorphology and socio – economical activities in the area. The CM2 power plant construction area is located in Northwestern corner of the land planned for Ca Mau fertilizer plant construction. The North of the plant is bordered with CM1 power plant, the West - with Cai Tau jail, the East and South will be bordered with Ca Mau fertilizer plant. According to Ca Mau province planning, the Ca Mau gas - power - fertilizer complex will be located within Khanh An industrial zone of the province in future. Residential areas are quite closed to the plant: Northern of the power plant No. 1 is residential area of hamlet 1 – consisting mainly of residential houses, orchards (coconut) and ornamental plant. Vegetation cover in left bank of Cai Tau river is mainly water coconut (Nipa). Residential area of hamlet 10, resettlement area and a part of U Minh 3 farm land consisting mainly of agricultural land and small replanted Eucalyptus forests locate adjacently to the Cai Tau jail in the west of the plant. Residential area of hamlet 4 and resettlement area locate in the Cai Tau confluence in the northeast of the plant. Residential area of hamlet 6 is adjacent to the South fence of the fertilizer plant. Further are residential areas spreading along two banks of Minh Ha canal. Here are about 1000 ha of 1 shrimp crop, which is transferred from rice fields by local residents. The environmental sensitivity indexes are assessed from medium to high. 5.3 DAMAGE ASSESSMENT OF ACCIDENTS During operation of the Ca Mau 2 power plant, dangers and risks including gas leakage, fire/ explosion and oil spill may occur. 5.3.1 Gas leakage in the plant 5.3.1.1 Possibility of gas leakage Gas fuel using for the plant will be supplied to the plant's fence by pipeline. As planned, natural gas volume using for the power plant is about 2.1 ÷ 2.4 million m3/day. From the plant's fence, gas will be directed to the turbines via the gas supplying system consisting of emergency shutdown valves, liquid separator, cold vents, measurers, filters and heaters. Gas may be leaked from valves, flanges, and gas treatment equipment as well as from gas pipeline in both operation and maintenance processes by many reasons as follows: - Internal corrosion: If water presents inside the pipeline, corrosion will occur due to the

reaction between carbon dioxide and water, which may still present in the gas flow, forming acid leading to corrosion;

- External corrosion; - Corrosion caused by pipeline unstable structure or mechanical damages including the

damage of material, weld, connection, etc.; - Abnormal situation such as the overpressure inside the pipeline, equipment, etc.; - Outside effects caused by sabotage, gas theft and other construction activities along the

pipeline; - Natural calamity: séisme, depression, etc... At the time of the report preparation, detail design of the gas supplying system is not yet available, therefore, possibility of gas leakage could not be calculated exactly. Estimated possibility of gas leakage occurrence from the main equipment of the gas supplying system and the gas turbines are summarized in following table:



Table 5.3 POSSIBILITY OF GAS LEAKAGE IN THE CA MAU 2 POWER PLANT

Equipment Frequency

of gas leakage/ unit

Quantity Frequency

of gas leakage

Source

Leakage from gas pipeline 4.9 x 10-5 150m 7.35 x 10-3 Leakage from ESV 7.3 x 10-4 1 0.73 x 10-3 Leakage from liquid separator 1.9 x 10-3 2 3.80 x 10-3 Leakage from measuring equipment 2.3 x 10-4 2 0.46 x 10-3 Leakage from filter 3.6 x 10-3 2 7.20 x 10-3 Leakage from gas heater 3.0 x 10-3 1 3.00 x 10-3

Leakage from gas turbine 4.6 x 10-4 2 0.92 x 10-3 OREDA- 97

Total 23.46 x 10-3 Notes: OREDA: Offshore Reliability Data Therefore, probability of gas leakage during the operation of Ca Mau 2 power plant is approximately 0.023 times/year. After the gas leakage exists, leaked gas/ vapor may mix with air to form flammable mixture, which will lead to fire/explosion accident only in case that flame source exists. Therefore, probability of changing one gas leakage to fire/explosion accident practically is very low. 5.3.1.2 Environmental damages Dispersion of leaked gas will be identified by SAFETI Micro Version 5.31 model. Here, only the worst gas leakage case as gas pipeline broken is modeled. Gas dispersion results of the SAFETI model running are summarized in Table 5.4.

Table 5.4 GAS DISPERSION RESULT BY SAFETI MODEL

Distance from leaked point

(m)

Natural gas content (% mol)

Concentration of CH4 in the air

(% mol)

Concentration of CO2 in the air

(% mol) 10 50.60 39.44 3.81 20 34.23 26.68 2.58 25 28.03 21.85 2.11

38.3 20.00 15.59 1.51 51.1 15.70 12.24 1.18 128 6.76 5.27 0.51

157.8 5.51 4.30 0.41 Concentration of CH4 within upper (UFL) and low (LFL) flammable levels of 15% and 5% respectively, which may potentially cause fire/ explosion, are found within radius 40 ÷ 200m from leaked point. And CO2 concentration that may be dangerous for human life are within radius of 10m from leakage point. Therefore:

− If accident occurs in the gas pipeline section from connect point between the power plant and gas supply next to the plant western fence, leaked gas will affect the plant administration area and may reach to Cai Tau jail area located next to the plant fence.

− In case that the gas pipeline is broken at other section, at gas treatment and distribution station or at two gas turbines, released gas will only affect to the CM2 power plant area.

Generally, leaked gas will cause direct effects on project workers working in the plant. Environmental impact caused by gas leakage is considered as minor. With probability of gas leakage occurrence at medium level, environmental risk of gas leakage accident is assessed as minor and acceptable.



5.3.2 Fire/ explosion accident 5.3.2.1 Risk of fire/ explosion accident During operation of CM2 combined cycle power plant,following typical accidents may happen:

- Fire/ explosion accidents generated by short circuit in main electrical equipment such as power generators, transformer, electrical lines. etc.

- Fire/ explosion accident caused by gas or fuel leakage: usually occurs at gas received/ delivered place, turbine covers, combustion chamber, gas filters, fresh and waste fuel tanks, etc.

Probability of fire/ explosion caused by short-circuit is actually very small. Up to now, there is almost no fire/ explosion caused by short-circuit in power plants. Therefore, only fire/ explosions caused by gas or fuel leakage are discussed hereinafter. 1. Fire accident The main fire accidents are classified as follows: Flash fire: Flash fire occurs with rapid rate of gas mass. It usually is fatal for anyone within or near to the flame. It occurs rapidly, so it will not damage to facilities presented in the incident area; Jet fire: Jet fire is a high intensity fire with flare type caused by gas or gas/fluid stream leakage under high pressure, released gas has spurt type and flame up. It is usually fatal for anyone within it and major damage to facilities within the flame. There is one special case of jet fire - impinged jet fire. Impinged jet fire occurs when leaked gas stream clashes into obstacles and forms a whirled vapor cloud. The formed whirled vapor cloud trends to disperse and quickly mix with air by the leaked gas stream dynamic. If the vapor cloud is fired, it will form high intensive fire. Pool fire: Pool fire is a fire on the surface of a pool of flammable liquid, which may occur either from a large rapid release or following a continuous liquid release. As with the jet fire, it may be fatal for anyone within or near to the flame, and may damage or destroy any properties within the flame. 2. Explosion accident Explosion is a process related to pressure wave formation generated from very quick energy freeing. Explosion accident type are described as follows: Vapor cloud explosion (VCE) Vapor cloud explosion can occur because of the combustion of a gas cloud, which is whirly distributed in the air. Whirled vapor cloud will accelerate the combustion process until the expanding cloud of combustion gases generates an appreciable overpressure and explosion. There are two types of vapor cloud explosion as follows:

- Unconfined vapor cloud explosion (UVCE) – this is a vapor cloud explosion occurred in open area. Normally, all UVCEs would not cause significant shaken effects due to vapor clouds will be combusted as eddy flame with high heat radiation.

- Confined vapor cloud explosion (CVCE) – this is vapor cloud explosion generated within small or closed space such as in tanks, drums, and pipeline or in closed building. This type of explosion usually creates strong shaken effects, which may destroy surrounding projects.



Two unconfined vapor cloud explosion and confined vapor cloud explosion explosions may be fatal to anyone within it and cause significant damage both within and beyond the region of the cloud. Boiling Liquid-Expanding Vapor Explosion (BLEVE) Boiling liquid-expanding vapor explosions most likely occur in fluid tanks under pressure. These accidents start with a fire outside the tank and the flame heat the fuel tank. At that time, liquid inside the tank will be boiled, evaporated and expanded leading to increasing vapor pressure inside the tank. When pressure exceeds the acceptable limit, the tank will be ruined and cause explosion. Besides, liquid fuel is flammable compound, its vapor releases out at high temperature and pressure, which will easily form a fire ball and continuously be burned by existing flame in the tank surrounding area. In case of the power plant, BLEVE accident may occur in the DO tank. Fire and explosion accidents. which may occur in the power plant are given in Table 5.5.

Table 5.5 SUMMARY OF FIRE AND EXPLOSION ACCIDENTS IN THE POWER PLANT

Accident type Cause Accident occurred place

Fire CH4 (natural gas). DO

In gas pipeline to turbines, gas filter station, DO storage tank area

Vapor cloud explosion (VCE)

CH4 (natural gas). DO

In gas pipeline to turbines, gas filter station, DO storage tank area

Boiling liquid expanding vapor explosion (BLEVE) DO DO tanks

Generally, leaked gases are easier to be fired than leaked DO because they spread more quickly and consists of many compositions with lower flash point. Most serious fire/ explosion accident, which may happen in the power plant, is the gas pipeline broken to the turbines. In this case, gas released volume is biggest. 5.3.2.2 Environmental damage Fire/ explosion accident will cause severe impacts on human, environment and damage equipment, and facilities. 1. Impacts on personnel The main effect mechanisms on human caused by fires/ explosion accidents includes: − Thermal impacts include thermal radiation and convective heat. The degree of damage

caused by thermal radiation is related to both the intensity of incident radiation flux and the time for which a person is exposed. Thermal radiation of greater than 37.5 kW/m2 will cause instant lethality (Table 5.6). However, such level threshold is quite high and unlikely to reach (only exceptional catastrophes).

Table 5.6 EFFECTS FROM THERMAL RADIATION [18]

Thermal radiation

criterion level Effects

37.5 kW/m2 Immediate fatality 12.5 kW/m2 Extreme pain within 20 seconds 4.7 kW/m2 Can bear for 15 – 20 seconds. harmful after 30 seconds contact2.1 kW/m2 Can be exposed for 1 minute 1.2 kW/m2 The same as sun shinning effect in summer noon



− Impacts of smoke: smoke comprising of toxic gases such as CO (main content) NOx and SO2 depends on the materials burnt, and leading to oxygen depletion and impaired visibility. CO is usually the main cause of death in fires. The effects of CO2 on the human body are two levels. Firstly CO2 will cause toxic effects when present in concentrations greater than 3%. Secondly CO2, when absorbed into the blood stream acts as a trigger to the brain to increase the breathing rate in order to draw more oxygen into the lungs.

− Overpressure explosion: an overpressure of 0.2bar (2.9psi) is adopted as the limit for causing fatality, i.e. all personnel inside the overpressure region of 0.2bar will die whereas no fatalities outside this region will occur. For those personnel trapped within a combustion cloud, regardless of the overpressure a 100% fatality rate is adopted as personnel will be caught in the flame.

2. Failures to Equipment Times to failure for an unprotected steel beam are 5 minutes under jet flame (250 kW/m2). 10 minutes under pool fire (150 kW/m2) and 30 minutes under thermal value of 37.5 kW/m2 while times to failure for pipeline and vessel are 5,10 and 60 minutes respectively [18]. If steel pipeline contains liquid under pressure, are heated in the fire, the pipeline and liquid temperatures increase. These impacts will reduce the pipeline durability, thermal stretching of pipeline section between two connected points make pipeline bend down, lessen pipe rack durability and damage flanges (Table 5.7).

Table 5.7 OVERPRESSURE EFFECTS [18]

Overpressure level Effect

0.35 Bar Heavy damage to factory, building and technological equipment

0.1 Bar Cause repairable damage for factory, building and technological equipment

0.05 Bar Cause window glasses broken and human injure

0.02 Bar 10% window glasses broken Here, only the worst case as fire/ explosion occurring due to gas pipeline from gas filter station to turbines broken is modeled. Results of the SAFETI Micro model running in this case are as follows:

Table 5.8 AFFECTED SCALE OF FIRE/ EXPLOSION BY SAFETI MODEL

Fire/ explosion type Effect level and extend Jet fire - Thermal radiation (kW/m2) 10 20 37.5 - Distance (m) 261.5 241.0 224.4 Flash fire Extend 444 m Boiling liquid expanding vapor explosion (BLEVE) - Thermal radiation (kW/m2) 4.0 12.5 37.5 - Distance (m) 195.8 112.5 63.44 Explosion with early ignition - Overpressure (bar) 0.02 0.14 0.21 - Distance (m) 342.3 183.4 170.9 Explosion with late ignition - Overpressure (bar) 0.02 0.14 0.21 - Distance (m) 339.8 182.9 170.4



According to model results in case of fire occurrence:

- If jet fire accident occurs in gas pipeline section from the plant fence to gas treatment and distribution station, it will cause critical harm to people presented in the whole plant area, especially in administration area. Overpressure effect also reaches to Cai Tau jail and the power plant administration areas;

- If jet fire accident occurs near the gas treatment and distribution station or in pipeline section from the station to the turbines, the main affected area will limit within the CM2 power plant. The Cai Tau jail and the CM1 power plant areas will also be affected in lower level. The most serious is effect of thermal radiation on DO tanks, which may lead to BLEVE accident;

- In case of flash fire, the flame may spread to the Cai Tau jail, CM1 power plant and Fertilizer plant.

Explosion accidents will affect mainly the power plant area due to thermal radiation and overpressure intensities usually quickly reduce by distances. Overpressure effect may occur in the CM1 power plant (at administration building and DO tank areas) in case of explosion with late ignition in gas pipeline running next to the plant fence. The power plant is constructed far from residential area (these residential areas themselves are thin population). Thus, occurred fire/ explosion would not affect adjacent residents. However, thermal radiation may affect crop productivity of some rice fields adjacent to the power plant. In case of fire/ explosion accident, a big volume of unburned CH4 and combustion products such as CO, NOx, organic peroxide and dust will disperse into atmosphere. These are main pollutants, which diminish air quality and may affect to human and fauna health. However, when accident happens, high concentration of these air pollutants in the atmosphere will only exist locally within the plant and in short period of time. These air pollutants will disperse quickly by wind effect and their concentration in the air will reduce under toxicity level. Thus, impacts on environment caused by fire/ explosion are only as minor and short-term. Thus, consequence of fire/ explosion accidents in the CM2 power plant is assessed as significant. However, possibility of fire/ explosion accident occurrence during the Ca Mau power plant operation is only at minor level. Therefore, environmental risk caused by fire / explosion accidents during the operation of CM2 power plant will only be at moderate level, but already reached the limit and should have risk monitoring and mitigating measures. 5.3.3 Oil and chemical spills 5.3.3.1 Chemical spills During the power plant operation phase, following main chemicals will be used: caustic soda (NaOH 30 or 50%), sulfuric acid (H2SO4 98%), hydrochloric acid (HCl 33%). These chemicals will be delivered to the plant by tank trucks. Chemical loading from the trucks to storage tanks may cause chemical spillage into environment. In addition, chemicals may also be leaked from storage tanks, pumps, pipelines, etc. However, there are impoundment dyke around chemical storage tanks in the plant and under tank bottoms are waterproof layers. Spilled chemicals will be collected and would not be released into environment. Therefore, chemical spill accident would not cause significant impact on environment. Although, chemical spill may threaten people due to these are toxic chemicals, which may cause skin burn, raspy throat, etc. The plant operators have to be equipped with protective clothing and to grasp thoroughly first aid action when being chemical adhesion.



♦

5.3.3.2 Oil spills

Risk of oil spills Oil spill causes during the power plant implementation include:

Table 5.9 POTENTIAL OIL SPILLS IN THE POWER PLANT

AND THE DO IMPORTING JETTY AREA

No. Causes Spilled oil Quantity to environment

1 DO tanks leaked/ broken Little (*)

2 Leakage upon DO transferring from the DO jetty to the storage tank area

Insignificant

Note: (*) DO storage tanks are placed inside impoundment dyke which can contain 110% tank capacity, so that spilled DO will be kept inside and release probability into the environment is very little

Generally, spilled oil volume into environment at oil spill accident in the power plant No. 2 is small, but the storage tanks located next to the canal K21 and the project area has dense river/ canal system, therefore, oil spilling into the river/canal environment will cause significant impact. ♦ Environmental damage Spilled oil into environment will evaporate, dissolve into water column, settle down into sediment surface and oil film spread on water surface. During the oil weathering process, the oil toxicity is reduced due to evaporating of the toxic compounds, particularly the aromatics with low boiling points (benzene, toluene, xylen, and ethylbenzene). If the evaporation is obstructed by natural dispersion, the dissolved amount of toxic components in water will increase. Low energy shoreline and sheltered areas are most likely at risk. Also possibility of accumulating higher concentrations of oil components will increase the risk for sheltered and shallow water. Because of the project area is confluence of 3 main rivers such as Ong Doc river, Cai Tau river and Trem river, it will be influenced by both Western tide from Ong Doc river mouth and Eastern tide from Ganh Hao river via Tac Thu canal. Eastern tide is semi- dual regime, and Western tide is dual one. Furthermore, tidal regime in Ong Doc river mouth and Rach Gia are not phasing synchronic. Current regime in the project area is very complicate. Oil spilled into the water environment will affect planktons, benthos, fishes and larva. Spilled oil also severely affects mangrove trees along the Cai Tau riverbank and aquacultural activities in the area. Impacts of oil spill into water environment have already assessed detail in DEIA report for the Ca Mau 1 power plant. Besides, when spilling into the environment, DO quickly evaporate. There are aromatic compounds in the DO vapor, which are very toxic. Light molecules with higher toxicity will be evaporated quicker. Constituents with boiling - point of under 200oC can evaporate entirely within 24 hours. DO vapor released into the environment will cause very strong and unpleasant odor leading to eye smarts and tearing. Evaporated organic substances cause eye smarts, respiratory trouble and may cause skin diseases for human at high concentration, forming photochemical oxygen, which thin ozone layer of stratosphere. Thus, in case that DO spill occurs at the DO tank area inside the Ca Mau 2 power plant, it will directly affect the plant workers, administration area of Ca Mau 1 power plant and fertilizer plant (if being constructed here). However, impacts on air quality will occur only in short period of time.



Chapter 6.

MITIGATING MEASURES FOR ENVIRONMENTAL IMPACTS Mitigating measures for adverse environmental impacts created during constructing and operating processing of Ca Mau 2 Power plant will be promoted in this chapter to ensure clean environment as well as sustainable development process. These mitigation measures base on improvements and adjustments of technology, management process and/or actual activities. They will be mentioned below, following development phases of the project and adverse environment impacts which need to be mitigated. 6.1 MITIGATING MEASURES DURING CONSTRUCTING

INSTALLING, COMMISSIONING PHASES Mitigation measures during construction, installation, commission phases are promoted as follow: 6.1.1 Soil quality The main purposes of mitigation measures on soil quality impact in construction area are: - Prevent soil erosion. - Prevent soil pollution from fuel assembling zone. - Reduce impact of solid waste. No Object/ Aim Mitigation measures Remain

impacts A1 Prevent

erosion Planning for surface leveling and consolidation in dry season, limiting consolidate time.

None

A2 Prevent erosion

Gravel, construction materials and stone will be spreaded on the roads where construction materials and super heavy equipment are transported.

None

A3 Soil pollution

Setting water-proof material layer below tanks to prevent pollutions.

None

A4 None hazardous solid waste

Contract with Ca Mau Water Supply and Urban Facilities Company for daily collecting and transporting to landfill, 9km far from project zone.

None

A5 Hazardous solid waste

Contract with Ca Mau Water Supply and Urban Facilities Company for periodic collecting (paint, solvents, oil filter, engine oil, wasted oil, weld stick, etc.) into safety tanks which marked clearly before transporting to the landfill stipulated by DONRE of Ca Mau.

Local impact in landfill only



6.1.2 Air quality The main purposes of mitigation measures on ambient air quality impact in constructing zone are:

- Minimize emission factors such as dust, SO2, and VOC to atmosphere from means and equipments served for construction.

- Minimize impacts of noise to residential zone. - Prevent respiratory diseases.

No Objects / Purpose

Mitigation measures Remain impact

B1 Exhaust from means of road transportation

Only use transportation means registered to meet legislative standards (TCVN 5947:1996)

Insignificant

B2 Dust Maintain spraying water frequently on constructing site, assembling material zone and center of transportation (especially in dry season).

Insignificant, met TCVN 5937:1995

B3 Dust Using cover material on transportation means to transport construction equipment.


B4 Noise Arranging working time logically to avoid rest time of residential zone, restraining of transportation in rush hour. Stipulate transportation speed for vehicles (<30km/h) to minimize noise generated, especially as passing through residential area or rest hours of residents.


B5 Dust, noise Maintaining frequently vehicles and constructive equipment to minimize noise, vibration and exhaust.

Insignificant, met TCVN 5949:1998, TCVN 3985:1999, TCVN 5937:1995

B6 SO2 Using low sulfur fuel (<0.25%) for vehicles and equipments.


B7 Prevent from respiratory diseases for labour workers

Well ventilation for working areas created dust and exhausted gas such as welding, paint spraying, warehouse and supply safety individual equipment suitable for workers as hamlets, masks, protective clothes…

None

6.1.3 Water quality The main purposes of mitigation measures on water quality impact surrounding the constructing zone of the plant are:

- Prevent groundwater pollution at material assembling zone supported construction works.

- Minimize adverse impacts to surface water.



No Object / Aim Mitigation measures Remained impacts

C1 Ground water, surface water

Using impoundment bunds for fuel tankers to avoid fuel leakage and spillage to adjacent canal.

Insignificant,

C2 Surface water Keeping safety in waterway material transportation.

Insignificant,

C3 Surface water Using freshwater to hydro-test and hydrotesting will be carried out following each phase (reuse and recycle) to save water.

In case of using chemicals, non-toxic or low toxic chemicals should be used and will not discharge directly to canal around project zone.

Insignificant,

C4 Surface water Install mobile toilets at camps during construction, not discharge domestic wastewater directly to adjacent canals.

Insignificant,

C5 Surface water Collecting solid waste completely in construction area, absolutely avoid discharging solid waste to canals.

None

6.1.4 Minimize negative impacts to Economic – Social Main purporses of mitigating measures on socio-economic impacts are: - Guarantee security - Protect laborer/worker health - Making active and helpful relationship with local population.

No Object / Aim Mitigating measure Remain impacts

D1 Local labour structure

Cooperate with the local authority to have a management plan of employee source in order to balance work-force and avoid adverse impacts to the local labour structure.

Negligible after construction phase.

D2 Community relationship

Keep closely relationship with the local inhabitants and authority in order to be informed and coordinated to solve problems generated during the project implementation.

Positive impacts

D3 Labour force Comply with the stipulations/regulations of Viet Nam Government in hiring the professional and manual labors. Make the convenient condition to enhance skill level for worker to be suitable with the plant development requirements.

Positive impacts

D4 Public order and security

Keep order and security at the project zone None

D5 Labor health Support safety and health protection equipment to the labours such as safety helmets, safety-working clothes, ears protective equipment and ensure the sanitary conditional working place.

None



No Object / Aim Mitigating measure Remain impacts

- Develop the Health and Safety Program aiming identification, assessment and inspection of the safety and health risk for the employees in order to have health protection plan during the project implementation.

The medical equipment of the plant may also be used for the local people in necessary case.

6.2 MITIGATION MEASURES FOR THE OPERATION PHASE As mentioned in environmental impact assessment chapter (chapter 4), main adverse environment impacts in operation phase are air emission, noise, wastewater, solid waste and incidents. Thus, mitigation measures focus as follows:

1. Air pollution treatment 2. Noise treatment 3. Waste water collection and treatment 4. Solid waste collection and treatment 5. Prevent incidents

6.2.1 Air pollution treatment During operation, main fuel used for the turbines is natural gas. In case of temporary interrupted of gas source, diesel oil will be replaced. The operation of gas turbines will regularly discharge NOx and CO to the environment through stacks. Mitigation measures for air emissions from stacks of gas turbines will be applied as follows:

No Object/ Aim Mitigation measures Remain impacts

E1 Exhaust gas from turbines

Use the F generation gas turbine with dry combustion chamber system to reduce NOx emission.



Regular monitor during plant operation to ensure that turbine operation complying with the design.



Comply strictly the maintenance schedule according to regulations of manufacturer



Install the main stack of 40m minimum height, stack diameter is about 6,5 meters so that pollutants in exhaust gas will be dispersed rapidly and ensure that NOX, CO concentration are always lower than TCVN 7440:2005 standard.



Install automatic monitor equipment at the top of the stacks.


E6 Exhaust gas from turbines & urgent diesel generator

Using high quality fuel with low sulfur (<0.25%) and create less dust.




6.2.2 Noise Noise will significantly generate due to operation of the plant and auxiliary-equipment such as gas turbine, steam turbine, pumps, compressor, fans, water treatment plant, cooling water pump, demineralization plant. So, the above equipment needs to be designed complying with noise standard applied for rural area in the boundary of the plant at every time:

No Object/Aim Mitigation measures Remain impacts

F1 Noise in plant zone

Select and install the low noise equipment and accessories.



Install soundproofed wall or construct soundproofed house around the equipment such as gas turbine, steam turbine, air compressor, etc. to reduce noise.



Air pipelines of gas turbines, cooling towers, safety valves, and diesel engine of fire-fighting pumps are also soundproofed; and parts of small equipment are sound-proofed in separated hull.



Install the noise and vibration sensor system at highly noise and highly vibration zone such as air compressor, turbines, etc.



Equipment in plant zone and port zone will be designed according to industrial standard to ensure that the maximum value of noise is 85 dBA at 1m far from noisy equipment.



Making period maintenance plan for equipment to minimize noise and vibration.



Equip anti-noise equipment for the workers working in the plant especially at the high noisy areas.


F8 Noise to residential zone

Establish a green-tree buffer zone between the project area and resident area by newly planting green-tree corridor around the plant.


6.2.3 Waste water treatment and discharge During operation phase of the plant, wastewater generated from many sources will be treated to ensure that it meets the standard before discharging to environment. It may be classified as follows. - Cooling water collected from cooling tower. - Waste water containing oil and lubricant is collected from production zone such as pump

station, transformer station, DO tanker, and workshop. - Waste water from sanitary toilet.



- Rainy runoff water directly discharge from non-production area of the plant such as transportation road, administrative area…

Specific treatment measures for each kind of wastewater will be shown as below:


G1 Cooling water discharge

Cooling water should take into open gully system to minimize the temperature (<40oC) before discharge to the environment, mitigate heat pollution.


G2 Cooling water discharge

Limit cooling water discharge at stand tide (v=0) to reduce heat pollution.


G3 Chemicals contaminated wastewater

Collect to the neutralize tank of wastewater treatment system. Treat until meeting Vietnamese standard TCVN 6984-2001 before discharge to Cai Tau river.

Insignificant, met TCVN 6984-2001

G4 Oily wastewater

Collect to oil separator tank and conduct to neutralize tank of wastewater treatment system. Treat until meeting TCVN 6984-2001 before discharge to Cai Tau river.


G5 Domestic wastewater

Collect into the septic tanks and then to the neutralize tank of wastewater treatment system. Treat until meeting TCVN 6984-2001 before discharge to Cai Tau river.


Detail of wastewater collection and treatment system of the whole plant is shown in Figure 6.1. Function of main equipment in share wastewater treatment system of both CM1 & CM2 power plants is summarized as below. Septic tank Septic tank is domestic wastewater collection site. Inside of the septic tank, BOD of domestic wastewater will be decomposed by anaerobic microorganisms. Oil separate tank Oil separator tank will separate the oil from water by effect of gravity. It will be designed to ensure that oil concentration in water equal to or less than 5 ppm according to TCVN 6984:2001. Neutral tank Neutral tank is a place that receives effluents treated from septic tank and oil separator tank as well as cooling tower. Neutral tank is equipped with pH and temperature sensor. NaOH or H2SO4 solution will be added to adjust pH complying with Vietnam standard. The temperature of output water from this tank will be adjusted to ensure the maximum variation is 5oC to compare with the water’s temperature of Cai Tau River. The output water of neutral tank will meet the Vietnam standard TCVN 6984:2001 and then lead to treated water storage tank.



Storage tank for treated water Function of storage tank for treated water is to maintain a stable discharging output as discharge treated wastewater to Cai Tau river. Discharging output will be tested by wastewater dispersion model to mitigate adverse impacts on surface water quality as well as disturbance impact on sediment of riverbed. 6.2.4 Collection and treatment system for solid waste Activities in construction and operation phases of Ca Mau power plant will generate solid waste and hazardous waste that is undesirable and unavoidable secondary products . The aim of mitigating measures is to limit generating rate of solid waste and to manage discharging activities. Basing on that, mitigation measures will be proposed as below:


H1 Solid waste - Contract with Ca Mau Water Supply and Urban Facilities Company for collecting and separating solid waste from discharged sources before treating and discharging to the environment.

- Strictly monitor and control wastes collection and treatment

Insignificant,

H2 Non- hazardous solid waste

Limit or recycle non-hazardous solid waste at realizable phases to mitigate quantity of solid waste.

Insignificant,

H3 Collecting of hazardous solid waste

Contract with Ca Mau Water Supply and Urban Facilities Company for collecting, transporting, treating and discharging hazardous solid waste according to Ca Mau DONRE regulations.

Setting solid waste containers accompany with guideline board at proper sites to limit scatter of hazardous solid waste in plant zone.

Building the temporary landfill in plant to storage hazardous solid waste before transporting for treatment.

Insignificant,

H5 Hazardous waste

Used chemicals and lubricants will be stored separately and suitably before reusing or transporting for treatment.

Insignificant,

H6 Other wastes Other wastes will be collected and discharged to local landfill

Impact in landfill only



6.2.5 Prevent incidents To ensure safety for all activities of the project, during general design phase of the Ca Mau power plant, the project owner had contacted and submitted a specific report about design of fire preventation and fighting system to Agency on Fire Protection and Fire Fighting - Ministry of Security. Preventing and protection measures will be developed and strictly implemented to avoid leaking or spillage of chemical and fuel. These measures are applied as follows: No Objects/

Aim Mitigation measures

I1 Leaking, spillage incident

Closely controlling liquid product export/import processing to minimize leaking and spillage incidents.


Install flow meter, overflowing pipes, and safety shutdown valves to prevent overflowing due to supply amount exceeds the maximum capacity of equipment.


Equip anti-corrosion layers for collective equipment, storage tanks and wastewater treatment facilities to prevent chemicals in wastewater eroded equipment and leaked out.

I4 Fire and explosion incident

Design and install fuel tanks complying to design standard of API 650, fire preventing and fighting standard agency of US and Vietnamese standard:

- Fuel will be stored at temperature below flashing point. Oil temperature will be controlled frequently. Setting cooling water tap at shell and bottom of oil tanks to prevent the increasing of oil temperature. Speed of cooling water spraying is about 30liters/second/meter in perimeter (TCVN 5307-1991). Cooling water will be taken from fire fighting water system.

- Arrange fuel storage tanks separately in safety embankment and they are put on waterproof hard ground to prevent spillage, leaking. Minimize distance between tanks and other equipment/construct is 30 meters (TCVN 2622-1995)

- Equipping oil storage tank that is painted by 3 rust-proof layers and using ventilated-ducts that limit operational pressure of storage tank is not over 0.15 bar.

- Install leaking detector, spillage control equipments and emergency shut-off valves at closing magnetic type to prevent leakage/spillage at fuel storage tank area.

- Install the automatic fire detector and automatic fire fighting equipment system at fuel tank areas and fuel pump station.


- Install the automatic fire detector, automatic fire alarm and auto fire fighting system at gas turbine and generator. When fire occurs, system will automatically control and transmit signals to



No Objects/ Aim

Mitigation measures

emergency stop the turbines, turn off ventilation fans, alarm and start the CO2 fire fighting system to extinguish a fire.


- Checking periodic the pump system, duct pipeline, fuel tanks, chemicals, fuel storage tanks and wastewater tanks in order to repair or timely replace damaged pieces of equipment, avoid causing spill incident.


- Establish the network of fire preventing and fighting system with safety exits and staircase at logical place and establish fire-fighting system according to technical requirement of industrial factory.

I8 All incidents - Establish emergency response plan for each kind of potential incident.

I9 All incidents - Equip and supply equipment and system to ensure safety for transportation, using and storing chemicals.

- Working places will be supplied with eye clearer, safety cleaning water taps, individual labour safety equipments such as: mask, safety glasses, gloves, etc.

- All factory members will be frequently exercised for fire preventing and fighting, oil spill response, especially members who working at storage area.

6.3 DECOMMISSIONING PHASE Adverse environmental impacts from stopping, moving and dismounting equipment of the plant are also similar to the ones generated from constructing/ installing phases. Thus, mitigating measures for adverse environmental impacts in this phase are similar as applied in construction phase. Besides, the plant will apply some specific mitigating measures for decommissioning phase as follows: K1. Establish logical plan for stopping activities and dismounting as well as pay attention

to interaction with other constructions located in the area; K2. Inform decommissioning plan to authorities, related institutions and individuals to

avoid generating interaction adverse impacts that causes disadvantage for them. K3. Dismounting time will be limited at minimum level and suitable dismount technique

will be used to avoid adverse impacts on adjacent environment and residents. K4. Collect and timely classify all dismounted materials to suitable reuse and discharging K5. All decommissioning activities will be monitored to avoid incidents causing

environmental impacts.



K6. Set a suitable zone for assembling dismounted materials and choose appropriate partners for liquidation equipments in order to quickly clean up the ground.

K7. Restoring plant area as original status by replanting vegetation cover in order to

support for land-use purpose of Vietnamese authorities and Project Management Board showing at that time.

K8. Cooperate with local authorities before dismounting in order to provide a specific plan

that helps the labour forces of the plant aim to minimize potential unemployment situation after plant stops its activities.

Decommissioning activities could be carried out after 25 operational years. At that time, Vietnamese and International environmental policies and laws could be much changed. Mitigating measures for environments impacts in decommissioning phase mentioned in this report could be changed to in accordance with future real situation.



Section 7.

ENVIRONMENTAL MANAGEMENT PLAN Environmental management plan for Ca Mau 1 power plant had been mentioned and approved in detail envieronmental impacts assessment (DEIA) report for Ca Mau power plant project. In fact, the Ca Mau 2 power plant is enlarged part of the revised project. Thus, environment management plan should be corrected to enlarge for the Ca Mau 2 power plant. Environment management plan is established according to Vietnam environmental standards basing on continuos process: “Planning, implementation, monitoring and assessment”. Environmental monitoring program has been established from design phase and carried out throughout project implementation. 7.1 ENVIRONMENTAL MANAGEMENT PLAN FOR THE PROJECT The project will establish, maintain objectives and devolve tasks for each rank and department related to environment. Environmental objectives and tasks of the project are identified based on environment requirement as follows:

Satisfy environment, safety and health standards established for the project;

Control and restrict all environment impacts to equal or less than the levels as mentioned in EIA report for the project;

Comply with commitments of environment management proposed by the Project Management Board and maintain technical parameters in order to meet environmental, safety and health related legal requirements as mentioned in this report;

Continuously upgrade safety and environment management during project implementation.

To implement objectives as above-mentioned, organization and direction for program implementation is an important factor and include as follows:

Establish a Safety and Environment Unit and in cooperation with other departments such as technical, security departments... to monitor safety and environment matters;

Provide information related to organization, regulations and necessary guideline for implementing environment practices;

Establish and implement checking, monitoring, review and audit to ensure that environment management plan is appropriate;

Improve and complete environment management system.



7.1.1 Environment Management Program Environment management program will include following activities: Monitor discharge sources and discharge sites; Waste management; Establish environment management plan; Establish emergency response plan; Train staff on safety and environment; Monitor, keep result of operations related to safety and environment of the project.

Regularly review and effectively audit environment management plan and correct the plan if necessary. 7.1.2 Checking and auditing environment management system Checking and auditing environment management system for Ca Mau 2 power plant as well as the Ca Mau 1 power plant include: Consider environment management system. This checking process will provide following

issues: − Existing environment and identifying potential environmental pollution − Introduce technical solutions and advanced technology as well as improve

environment management and monitoring programs so that they are suitable for reality situation.

Consider environment: periodically inspect on special subjects as follows:

− Hygiene condition at the project area − Wastewater system, wastewater quality − Waste management − Equipment and measure for accident response

Auditing environment: auditing environment management and technology issues that

may be implemented “separately” or in coordination with safety audit. Results of auditing, assessing, conclusions and recommendations will be documented to establish a concrete implementation plan and considering, correction and improve factors in environment management system so that they are suitable for reality situation. 7.2 ENVIRONMENTAL MEASURING AND MONITORING PROGRAM Main objectives of environment monitoring plan include: - Identify all environment changes which may cause adverse effects on environment by

the project implementation; - Monitor discharge sources (gas emission, waste water and solid waste) and operation of

environmental protection equipments in order to ensure that these activities will comply to legislative requirements;

- Check monitoring process and inspect installation system and equipments in respect of pollution prevention and control;

- Prevent potential incidents; - Propose appropriate environment protection measures based on results of

environmental monitoring; - Overcome and repair all weak-points based on results of environment monitoring

program.



Environment monitoring for the project is divided into 2 following types: - Regular monitoring gas emission quality, waste water generated by project operation; - Periodical monitoring surrounding environment of the project area. Environment monitoring program will be carried throughout all project implementation phases, from pre – construction, post – construction and during operation phase. 7.2.1 Monitoring Program for the Discharge Sources Purpose of regular monitoring discharge source is to ensure that waste sources must be treated to meet discharge standards before discharging into environment to mitigate environment impacts generated and have timely measures for preventing and correcting. . Monitoring program for the discharge sources of the CM2 power plant is similar as the one for CM1 power plant including regularly monitoring all discharge sources in plant (gas emission, waste water and solid waste). Monitoring will be implemented regularly by directly automatic measuring at discharge source or sampling to analyze regularly. Results of sample measuring and analyzing will be recorded in files to monitor and audit. Refer to environmental survey and monitoring programs for the thermal power plant projects promulgated by Agency of Environment - Ministry of Science, Technology & Environment in 1999 [20], monitoring program of discharge sources includes: - Monitor strictly collecting and discharging solid waste in construction, operation and

decommissioning phases of the project; - Daily monitor the discharge sources of wastewater, gas emission, checking operation

process of wastewater treatment system to timely repair if wastewater quality not meet the Vietnamese standards ;

- Monitoring results will be documented to report to higher authorities to have timely

solvable measures in order to prevent environment impacts.

Table 7.1 REGULAR MONITORED PARAMETERS IN CA MAU 2 POWER PLANT

Discharge source

Parameter Frequency Sampling site

Gas emission Dust, SO2, NOx, CO, CO2

Weekly 3 sampling sites at following location: − 2 sites at two stacks − 1 site at cooling tower

Noise Noise, Vibration Monthly 4 sampling sites at following location: − gas turbine, − steam turbine − gas compressor − Cooling tower

Cooling water

Discharge flow, pH, temperature, TSS, Cl-

Weekly 1 site at discharge point in the plant before flowing to the discharge canal to Cai Tau river

Industrial wastewater

pH, temperature, turbidity, TSS, BOD5, total oil content

Daily - 1 site at input of wastewater treatment system

- 1 site at output of wastewater treatment system



Continuous gas emission monitoring system of gas turbine Beside above-mentioned monitoring system, project owner has provided a set of continuous gas emission monitoring system of two gas turbines of CM2 power plant. This is an automatic system used for monitoring gas emissions from two gas turbines. This system will monitor CO, CO2 and SO2 content from each gas turbine and continuous monitor O2 and opaque of discharged gas. Equipment of continuous air emission monitoring system will be calibrated to ensure that emission gas limits must be complied with Vietnam standard requirements. The continuous air emission monitoring system will be placed in air conditioner roof cover, air samples will be taken from discharged gas pipe of each gas turbine. Sampling pipes will be provided an electric heater to prevent condensation and absorption discharge gases. Another function of this system is to keep sample for each channel and is used in the case of transferring it to take gas samples of other turbine. 7.2.2 Environment monitoring program in the vicinity Characteristic of the power plant is situated on wetland area, environment diversity and sensitive including canals, rivers, agriculture soil, residential area and mangrove, so surrounding environmental monitoring program will be undertaken throughout project execution to immediately identify environmental pollution source and propose treatment measures. To identify environment changes, environmental measuring and monitoring program will be implemented before starting construction works and throughout operating phase until finishing decommissioning activities. Environment measuring and monitoring program will be implemented according to each phase as follows: 1. Pre – construction phase Environmental measuring and monitoring program will be implemented before starting plant’s construction, which is considered as environmental baseline study. Environmental baseline study had carried out as a part of EIA report. Collected data from environmental baseline study will be used as basic for environment management and next monitoring activities. Environmental baseline study for Ca Mau power plant project area had been supplemented surveyed in period from December 19th to 24th, 2005 by RDCPSE. Analytical results of Environmental baseline are shown in section 3 of this report. Information and database in survey program include:

- Biological environment: terrestrial and aquatic ecosystem;

- Socio – economic condition in the project area;

- Sampling and analyzing physio-chemical and biological parameters will identify the environment quality of the project area including air, water, soil, and sediment quality. Sampling locations are shown in table 7.2.



Table 7.2 ENVIRONMENTAL SAMPLING LOCATIONS AT CA MAU POWER PLANT IN DECEMBER, 2005

Co-ordinate Sample

type Station Sampling location Latitude (North)

Longitude (South)

R1 Cai Tau river – discharge point of cooling water CM1 09o14.993' 105o03.555'

R2 Cai Tau river – intake point of cooling water 09o14.544' 105o03.938'

R3 Ong Doc river – far from downstream of Tac Thu sluice of 500m 09o13.857' 105o04.512’

Surface water

R4 Ong Doc river – far from downstream of Tac Thu sluice of 1000m 09o13.586' 105o04.736'

Đ1 In the plant area – bordered on the Power plant 1 09o14.333' 105o03.637' Soil

Đ2 At surface sluice of Power plant 2 09o14.262' 105o03.658' Ground water

G1 Site of drilling well of Lilama Project Management Board 09o14.320' 105o03.582'

K1 Power plant 2 area 09o14.529 105o03.910' K2 Far from south of main stack base of

Power plant 1 of 1600m 09o13.963' 105o03.541'

Gas

K3 Cai Tau residential area 09o14.456' 105o04.456' Note: - R1÷ R4: sampling sites of surface water, sediment, benthos and plankton; - Đ1÷Đ2: soil sampling sites - G1: ground water sampling sites - K1 ÷ K3 air sampling sites 2. Construction phase During construction phase, construction activities must ensure to properly implement technology requirements and appropriate to mitigation measures of environmental impacts as mentioned in this report. EPC constructors must take responsibility for dust, noise monitoring at the project execution area and discharge flow from wastewater treatment system in order to ensure that pollution parameters are within allowable standards. After finishing construction and commissioning, the project will carry out one more survey and sampling in order to identify natural environment changes in construction phase. Monitoring parameters and frequency are shown in Table 7.3 and 7.4. Results of environmental monitoring in pre – construction phase and construction phase will be baseline data for environment monitoring of the next phase. 3. Operation phase Due to the surrounding area is influenced by combined impacts from project life-time operation, it is necessary to have period monitoring plan, equipment maintenance plan in order to immediately detect and prevent potential impacts on economics as well as natural environment during operation phase of the plant. Result of environmetal monitoring, equipment system maintenance as well as breakdowns and incidents in operation phase must be monitored, recorded in files and reported in detail. Monitoring program of ambient environment of the power plant is undertaken 2 times/year in the dry and rainy season.



Monitoring program of ambient environment will be enlarged for Ca Mau 2 power plant. Supplementation sampling location, analytical parameters and monitoring frequency at surrounding of Ca Mau 2 power plant are shown in table 7.3 and Figure 7.1.

Table 7.3 PERIOD MONITORING PARAMETERS AND LOCATIONS AT SURROUNDING AREA OF THE POWER PLANT

Environment Parameter Sampling site Air Dust, temperature, humidity,

SO2, NOx, CO, CO2 2 sites, in which: − 1 site at 1,775m far from CM 2

Power plant’s stack’s foot toward South-Southeast

− 1 site at temporary resettlement areaSurface water ToC, pH, TSS, COD, BOD5,

DO, Cl-, total N, total P, SO42-

, total oil, total coliform, heavy metals.

2 sites, in which: − 1 site at discharge point of cooling

water of the CM 2 power plant to Cai Tau river

− 1 site far from downstream of Ong Doc river of 500 - 1000m

Ground water Colour, pH, TSS, Cl-, hardness, NO3

-, NO2-, SO4

2-, Coliform.

1 site, in which: − Cai Tau jail area

Sediment Hydrocarbon, Heavy metals

2 sites at surface water sampling location

Biology Zooplankton, phytoplankton, benthos

2 sites at surface water sampling location

Besides, in Ca Mau Integrated Gas – Power – Fertilizer (IGPF) area, an automatic monitoring station for ambient air environment will be equipped. 4. Decommissioning phase During decommissioning phase, dismantling works must be strictly monitored on-site. After finishing all dismantling works, an environmental survey program will be carried out in the surrounding project area to ensure that residual impacts are significant and acceptable. Sampling locations as well as monitoring parameters in environmental monitoring program in this phase are the same as periodically monitoring for surrounding environment quality and are shown in Table 7.4.

Table 7.4 MONITORING FREQUENCY OF SURROUNDING ENVIRONMENT OF THE POWER PLANT

Phase Monitoring Frequency Pre-construction 1 time in rainy season and 1 time in dry season for

environmental baseline study

Construction 1 time after finishing plant construction and installation

Operation 2 times/year

Decommissioning 1 time survey Note: Monitoring frequency may be changed when particularly legal regulations are promulgated in the future.



Results of environmental measuring and monitoring program will be kept on records and submitted to competent authorities of environment such as Ministry of Natural Resources and Environment and Department of Natural Resources and Environment in Ca Mau province. 7.3 ENVIRONMENTAL MANAGEMENT TRAINNING PROGRAM Safety and environmental management training program is an important part in environment management program. During construction and installation phase, Project Management Board will coordinate with constructors in order to ensure that project staffs are trained on labor safety and environment protection. In operation phase, all staffs of power plant will be trained on environment safety throughout training courses, operation processes and guidelines, fire fighting exercises and practices, ect. Project Management Board will establish and maintain training programs that regularly updated to help staff at all levels and related functional departments are aware of their responsibility on environment protection. Environment training programs will be implemented appropriately for groups selected in the project and include as follows: Environment Management system; Environment guidelines and procedures; Vietnam Environment law; Existing environment problems and detailed environment problems for the project; Mitigation measures on organization and technique; Environment protection in production; Regularly audit and assess environmental protection implementation; Periodically training courses on incident response, first aid, fire and explosion, ect.

Beside, project staff will be also trained on special subject. Project Management Board takes responsibility for ensuring information quality and monitoring overall environment management function. 7.4 EMERGENCY RESPONSE PLAN Emergency incident response plan of Ca Mau 1 power plant has been established and approved to mitigate harms on humans and environment in the project area and its vicinity in case of incident. This plan will define necessary activities when incident happens, in order to minimize human, property, equipment and environment damages. This plan must be also corrected and enlarged for Power plant 2. Emergency response plan includes:

Classify and determine all potential incidents due to equipment operation such as fire and explosion caused by external cause or pipeline itself and equipment;

List of internal and external notices;



Schema on emergency responsibility organization and information notification sequence;

Identify role, responsibility of organizations and personals in incident response;

Necessary equipments for directions and on-site response;

Periodically training and on emergency response:

- Study and practice emergency response exercises, basic first aid, safety and fire-explosion courses …

- Study on operation, guideline of plant safety and protection regulation for local people;

- Continuously draw experience from real practice and throughout emergency response exercises

Regularly update new information for emergency response plan.

Particular implementation steps in case of emergency response:

- Isolate whole system or pipeline equipment.

- Communicate to emergency direction board, emergency assistance board and other response organizations.

- First aid and move victims away from incident area.

- Response the system from emergency situation. Beside, prevention and fire fighting plan for the CM2 Power plant is also particularly edited and approved by related competent organization. Briefly, during operation, safety objectives in production process will always be paid attention and so, mitigation measures as above mentioned will be strictly complied to reduce as much as possible potential risk of the abnormal accidents affected the Plant operation.



Section 8. CONCLUSIONS

The revised project of Ca Mau Power Plant is one of the strategic projects of Vietnam in order to use most effectively the natural gas from Southwest gas fields and meet the power shortage demand in the future. The project development will impulse the local economic development and promote the national industrialization and modernization. It is the strong motive force to stimulate the development and the change of economic structure in the province, to improve the province's economics and society and keep the security and politics at the border of Southwest area . The Ca Mau 2 power plant has the designed capacity of 750 MW which is undertaken on the basis of multiplying two times with the Ca Mau 1 power plant's capacity, so it has similar configuration as CM 1 power plant. The Ca Mau 2 plant will be constructed simultaneously with the Ca Mau 1 plant on the proposed fertilizer plant's land and is planned to complete in 2008. Similar to Ca Mau 1 power plant, the construction and installation process of Ca Mau 2 power plant will disturb the soil structure, increase the alum creating ability and soil erosion, especially at the beginning of rainy season period. The dredge activities to widen port and the equipment transportation will change the local water current regime and disturb the water environment. It makes increasing the suspended solid and pollutants content in river-bed (mud) at the area near Cai Tau confluence. The impact level is assessed as medium during the construction process. In the operational phase, the content of pollutants in emission gas at the two main stacks of the plant in both cases using natural gas and diesel is lower than the emission gas standards TCVN 7440:2005 applied for thermo-electric industry. In the field of gas emission in both cases of the two power plants (Ca Mau 1&2) using total natural gas and using total (100%) diesel with maximum sulphuric content of 0.5% weight, the maximum hourly and daily content on ground of the emission gas (NOx,CO,SOx) is lower many times than the Ambient Air Standards of Vietnam TCVN 5937:1995. It shows that the emission gas of Ca Mau 2 power plant in both cases using natural gas and diesel affects the local ambient air environment insignficantly. The continuous intake of supplementary cooling water with the volume of 2 m3/s from Cai Tau river and the frequent discharge of cooling water or treated industrial wastewater into Cai Tau river will change the local current of this river system. In dry season (November to April), when Tac Thu sluice is opened, the continuos intake of cooling water for both power plants (1&2) will increase the water volume from Cai Tau river toward Ong Doc river, and increase the current velocity, but not affect the volume of irrigational water for local agriculture. When the Tac Thu sluice is closed, the maximum current upstream and downstream of Cai Tau river is decreased much in comparison with the one in the case of opening Tac Thu sluice. The continuos intake of 2 m3/s cooling water for both power plants (1&2) makes the water level of Cai Tau river decrease from 1 to 6 cm. At cooling water intake site, the flow decreases about 2.3 to 2.7 m3/s. At cooling water discharge site of two power plants (1&2), the flow decreases about 4.3 - 4.7 m3/s.



The continuos cooling water discharge of Ca Mau 2 power plant into Cai Tau river (option 2) will be more optimal than the discharge into Cai Tau confluence (option 1). In the normal operation condition, with the temperature of cooling water discharge of 35oC, the continuos cooling water discharge of two power plants will only slightly increase (average one of 1.1oC and highest one of 3.5oC at calm tide) temperature of the river. This will impact insignificantly on water quality of Cai Tau river and Ong Doc river. In case of tail gas incident, with the cooling water discharge temperature of 40oC, cooling water discharge of two power plants will cause increasing the temperature significantly for section of Cai Tau river from cooling water discharge site from the CM 1 power plant to Cai Tau confluence (average increase temperature of 2.3oC and highest one of 9oC at calm tide). However, Cai Tau river section is affected by East and West sea tide, so the high temperature increase only lasts from 30 minutes to 1 hour a day. Because the treated industrial wastewater volume of two power plants (1&2) is very small, the discharge of the treated industrial wastewater volume of the two power plants (1&2) insignificantly affects the Cai Tau and Ong Doc rivers' water quality. In order to conduct environmental protection better, the project will develop environmental management plan combined with environmental monitoring plan. The environmental management plan will control and implement the mitigation measures, simultaneously guide employees to obey strictly the environmental standards in order to ensure all of the pollutants created in operational period will be strictly controlled within allowable limit. Recognize the importance of environmental protection, the project owner commits that they will strictly obey the Vietnamese standards, the advanced technical solutions, the mitigation measures for environmental pollution and the suitable environmental management plans as mentioned in this report including:

1. Emission gas SOx, NOx and dust at the discharge sites meet TCVN 7440:2005, other emissions will comply Vietnam current environmental standard;

2. Pollutant content of the ambient air quality will meet the Vietnam current environmental standard;

3. Temperature of cooling water discharge will comply the Vietnam current environmental standard (<40oC)

4. Treated industrial wastewater will comply the Vietnam current environmental standard In the project implementation period, the project owner always anticipates a part of budget for environmental protection including:

1. In the construction, installation and commissioning phases: the expenditure for environmental protection (including construction and installation of wastewater treatment system; waste collection and treatment, etc.) is in the EPC package of the power plant. Whole of the treatment system will be completed at the plant’s commissioning phase.

2. In operational phase: the expenditure for environmental protection will be in the plant's operational fund.

Furthermore, the project owner will closely coordinate with the state organizations and the local authorities to implement the project safely and to get the high economic and social effect. The project owner commits to strictly implement the measures mentioned in the EIA report in order to implement the project safely, effectively; less affect the environment and will be legally responsible if the project breaks the Vietnamese environmental regulations and standards and if the environmental pollution accident occurs.

APPENDIX 1

APPROVAL DECISION OF ENVIRONMENTAL IMPACT ASSESSMENT REPORT

1. Approval Decision No.460/QĐ-BTNMT of MONRE on April

23, 2004 for DEIA report of Ca Mau power plant. 2. Approval Decision No.297/QĐ-BTNMT of MONRE on March

23, 2006 on approval of supplemental EIA report for Ca Mau power plant.

APPENDIX 2

BASIC THEORY AND RESULTS OF AIR EMISSION MODEL

1. CA MAU 2 COMBINED CYCLE POWER PLANT – USING 100%

NATURAL GAS FUEL

2. CA MAU 2 COMBINED CYCLE POWER PLANT – USING 100% DIESEL OIL FUEL

3. CA MAU 1&2 COMBINED CYCLE POWER PLANTS – USING 100% NATURAL GAS FUEL

4. CA MAU 1&2 COMBINED CYCLE POWER PLANTS – USING 100% DIESEL OIL FUEL

APPENDIX 3

BASIC THEORY AND RESULTS OF COOLING WATER DILUTION MODEL

EMISSION GASES DISPERSION MODELING To determine the dispersion of emission gases from stacks in the Ca Mau power plant, a refined dispersion modeling program ISC- ST3 (The Industrial Source Complex Short-Term) have been used. This model was developed by the US Environment Protection Agency and is used to predict pollutant concentrations from continuous point, flare, area, line, volume and open pit sources. The ISC dispersion model combines various dispersion modelling algorithms to assess the air quality impact of emissions. The basis of the model is the straight – line, steady state Gaussian plume equation. The concentration of one site far from stack a distance x, from central line of plume horizontally a distance y, from ground a distance z; is calculated by basic equation: Where:

C(x,y,z) = Q 2πσyσzu

exp - y2

2σy

2exp

- (z – H)2

2σz

2exp

- (z+H)2

2σz

2+

C(x,y,z): Concentration at co-ordinate of (x,y,z), (g/m3) u : Wind velocity at the top of stack (m/s) Q : Loading of polluted substances (g/s) H : Stack height (m) σy ,σz : Vertical and horizontal deviation of gas plume (m)

Neccessary input data for the emission dispersion model running are as follows:

Neccessary data Unit Type of emission source Point; Area Number of emission source 1..nStack height mStack diameter mStack position (x,y) mExit gas temperature oC or KelvinGas exit velocity m/sElevation of emission area in comparison with general foundation

m

Pollutants (gas / particulate) NOx, COx, SOx; dust....Pollutant rate g/sPollutant's concentration mg/Ncm (mg/m3)Length of emission area mHourly meteorological data : - Year; month; day; hour (1997; 1..12; 1..31; 1..24)- Wind direction 0..360o

- Wind speed m/s- Ambient temperature oC- Atmosphere stability A..GType of emission area Urban, ruralEmission flowrate of each source kg/ min.

i

ISCST3 requires hourly meteorological data records to define the plume rise, transport, diffusion and deposition conditions in a given area. The model estimates the concentration or deposition value for each source and receptor combination for each hour of input meteorology, and calculates selected short – term or the entire period of input meteorology averages. To calculate the distance (meter) from a stack to an impacted areas, the UTM Coordinate System is used. For example, the coordinate of a stack at (7 43400m E, 11 56600m N) is briefly written (43400, 56600).

ii

CALCULATION METHOD FOR DISPERSION OF ORGANIC POLLUTION IN RIVER/CANAL SYSTEM

Present, domestic wastewater occupies up to 90% of total wastewater volume causing water source pollution, of which mainly are organic wastes. In self- cleaning process, organic wastes are mainly biochemical decomposed and dilluted by current. Required oxygen volume for microorganisms to decompose organic wastes in one volume unit of wastewater sample is called Biochemical Oxygen Demand and counted by mg of oxygen per litre. Natural water has dissolved a certain oxygen volume called Dissolved Oxygen. Oxygen content in water changes by many reasons as follows: - Oxygen dissolution from the air into the water. - Oxygen generation in the water caused by photosynthesis of phytoplankton - Oxygen loss for oxidation to decompose organic compounds in the water and

sediments in the bottom. - Part of oxygen is neccessary for plankton respiration. Imitating DO, BOD changes in the water is great part of water quality researching projects. On the one hand, DO is general parameter for life in water environment and almost wastes interact with oxygen. On other hand, BOD is main reason for DO content reduce in the water. Therefore, BOD imatating model always associates with DO. In recent years, due to quick development of Personal Computer and perfection of digital methods, mathematic model for water quality imitating proves as a strong, rapid and economic tool for designers and managers, especially in water resource sector.

Basic equations and solved algorithms When examining water quality problems in river/ canal system, one-way model is often used and hydraulic components (field of velocity) are drawn from measuring or from hydraulic model through solving following set of Saint-Venant one-way equations:

)1(qxQ

tZW =

∂∂

+∂∂

)2(02

2

=+∂∂

+⎟⎟⎠

⎞⎜⎜⎝

⎛∂∂

+∂∂

ARCQQg

xZgA

AQ

xtQ

where : W - width of water surface; A - area of horizontal tangent surface; Z - water level in comparison with standard altitude; Q - flowrate through horizontal section; g - gravitation acceleration; C - resistance coefficient; R - hydraulic radius; q - entering flowrate such as pump, discharge; t - time ; x - coordinate along the river. After solving (1)-(2) by digital method with appropriate begining and edge conditions, water level Z, flowrate Q and field of velocity are found.

iii

BOD and DO changes in the river/ canal are described by following one-way dispersion equation: a) For BOD with concentration B :

)3().( 312

2

qBAqBKKB

Aq

xBE

xB

AQ

tB

++−−∂∂

=∂∂

+∂∂

b) For DO with concentration D :

)4(.)( 122

2

qs DAqBKKDDD

Aq

xDE

xD

AQ

tD

+−−+−∂∂

=∂∂

+∂∂

where : Bq, Dq are BOD and DO contents in entering flow. Ds is oxygen saturation. K1 is constant for BOD change. K2 là gas penetration constant. K3 is constant for BOD change by sedimentation. U=Q/A is average current speed. E is dispersion coefficient. Generally Ds is a function of temperature. Gas penetration constant K2 usually is function of current speed and depth. One of the practical formulars for K2 is Bennett and Rathbun formular as follows: U 0.674

K2 = 2.33 ⎯⎯⎯⎯ h 1.865

where : U - average current speed ( m/s) ; h - average depth (m) ; K2 measured by unit/day. Wrigh and McDonnel [1] have recomended following formular for K1: K1 = 99.3 Q -0.49 ( 1/day ) both K1 and K2 are functions of temperature. Q (m3/h) is flowrate. To examine self- cleaning ability of each river, self- cleaning constant f is advanced and defined by following formular: f = K2 / K1. It is noted that although K2 and K1 depend on temperature, their ratio, f, almost not depends on temperature. Equations (3)-(4) have the same form:

)5(2

2

bSaxSE

xSU

tS

+−∂∂

=∂∂

+∂∂

where a > 0 and b is known constant; S is BOD or DO contents. Equation (5) is solved digitally by decomposition method, of which the loading equation is solved purely in first time step:

)6(bSaxSU

tS

+−=∂∂

+∂∂

but along the set of specific lines dx/dt = U, its root is:

( )abat

abSS +−−= exp)( 0

where S0 is concentration at the specific line root.

iv

Following is to solve diffusion equation:

2

2

xSE

tS

∂∂

=∂∂

After the solving process, we have root of (5) equation within one time step. This process is repeated for next step.

Calculation program for BOD and DO contents in complicated river/ canal system WQ

Based on the above mentioned algorithms, a computer program has been developed named WQ (Water Quality). Calculated results are as follows: - Water level, flowrate, speed, BOD and DO contents at all concerned points in the

river system. - Maximum, minimum and average values of the above mentioned parameters. - Self- cleaning constant at concerned points. - It is available to imitate complicated system with water storaging areas, water

supplying and using projects, tidal affected river/ canal systems. Reference 1. WHO, Assessment of sources of Air, Water, and Land Pollution, Part II. Geneva,

1993.

v

Documents

ca mau eia.pdf (PDF) - AGA-Portal · contents pages 1. introduction 1 1.1 objective of the report 1 1.2 overview of ca mau power plant project 1 1.3 data and information sources 2