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Dr. BUI Xuan Thanh

Associate Professor

Faculty of Environment & Natural Resources

Ho Chi Minh City University of Technology Email: bxthanh@hcmut.edu.vn (+84 965 37 6073)

Taipei - Taiwan

International Conference on Forward-looking Water Management November 8-9, 2018

Organized by

Water Resources Agency, MOEA, Taiwan

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CONTENT

General Information 1

Water Pollution in Viet Nam 2

Solutions 3

Conclusions 4

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Two biggest deltas in Vietnam:

• 68.4% of country rice cultivated

areas

• 71.3% of rice quantity

GENERAL INFORMATION

Vietnam Delta (Wikipedia)

Red River Delta:

Population: 19999 people

Total area: 21068 km2

Density: 949 people/km2

Mekong Delta:

Population: 17331 people

Total area: 40548 km2

Density: 427 people/km2

4 4

VIETNAM WATER MARKET

In the next 5 years, the demand for

water sector investment

10 billion USD

Investment demand (Statistics Ministry of Construction, 2018)

Water Supply

3.3 billion USD Water Drainage

6.9 billion USD

5

VIETNAM WATER MARKET

Water Supply (Vietnam Environment Administration Journal)

• 100 enterprises manage ~ 500 large & small water

supply systems in urban centers nationwide.

• Total water supply capacity: 7 million m3/day

Price: Vary with locations & water resources (1$ =23,000 VND

Location Company Price (VND/m3)

Ha Noi Hanoi Water Ltd. Co. (HAWACO) 5,973

Ho Chi Minh Sai Gon Water Supply Corp. (SAWACO) 5,300

Binh Duong Binh Duong Water Environment JSC. (BIWASE) 8,500

Da Nang Da Nang Water Supply JSC. (DAWACO) 3,809

Tuyen Quang Tuyen Quang Water Supply & Sewerage JSC 4,500 – 5,500

Industry/Services Most of industries/services 12,000

6 6

VIETNAM WATER MARKET

Profit:

• Saigon Water Corp. (SAWACO): subsidy

• PHUWACO water supply JSC: Net profit ~ 6.53% in 2012. (after 5 years)

• Ben Thanh WASUCO JSC: Net profit ~ 3.3% in 2017.

• Dong Nai Plastic Corp. (Just invest in Water Sector in 2017):

Revenue ~ 70 billion VND & Net Profit ~ 5 billion VND.

Water Sector in Vietnam:

• Steady growth & good profits

• Lots of attention.

(Doanh nhan Sai Gon, 10/7/2018)

7 7

WATER SUPPLY - HCMC

Others(Private

company)

Tan PhuWTP

Kenh DongWTP

Tan HiepWTP

BOO ThuDuc WTP

BOT Binh AnWTP

Thu DucWTP

Ground water Surface water Sai Gon River

Surface water Dong Nai River

75,000 m3/day (5%) 1,445,000 m3/day (95%)

Water Production and Distribution of SAWACO

(SAWACO, 2014)

Water supply planning until 2025 (Prime Minister Decision 729/QĐ-TTg)

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Surface Water

Issues

9 9

Saigon river water quality is being deteriorated with time, increase in organic & ammonia pollution (Dan et al., 2013)

COD, DOC > standard limit for water supply purpose

ORGANIC POLLUTION In SAIGON RIVER

Variation of COD & DOC along Saigon river:

From Dau Tieng lake to Downstream (km)

10 10

(Dan et al., 2013)

Ammonia > Standard limit for water supply purpose (QCVN 08-MT:2015/BTNMT: NH4-N < 0.3 mg/L)

NUTRIENT POLLUTION In SAIGON RIVER

Variation of TKN & Ammonia along Saigon river: From Dau Tieng lake to Downstream (km)

11 11

SAIGON WATER QUALITY: Hoa Phu STATION (SAWACO, 2016)

Parameter Unit 2011 2012 2013 2014 2015

pH - 6.17 ± 0.37 6.22 ± 0.13 6.33 ± 0.23 7.07 ± 0.06 7.12 ± 0.06

Color Pt-Co 288 ± 114 256 ± 113 189 ± 59 291 ± 147 280 ± 162

Turbidity NTU 41 ± 17 35 ± 17 25 ± 10 40 ± 19 44 ± 19

Alkalinity mg/L 17 ± 4 17 ± 2 16 ± 3 25 ± 4 25 ± 3

SS mg/L 31 ± 18 26 ± 9 21 ± 10 35 ± 18 33 ± 12

Ammonia mg/L 0.47 ± 0.24 0.33 ± 0.18 0.34 ± 0.18 0.24 ± 0.05 0.20 ± 0.09

Nitrite mg/L 0.01 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 0.01 ± 0.01 0.01 ± 0.02

Nitrate mg/L 0.50 ± 0.20 0.58 ± 0.16 0.35 ± 0.13 0.62 ± 0.27 0.98 ± 0.15

Fe mg/L 1.05 ± 0.22 0.95 ± 0.21 0.76 ± 0.16 0.96 ± 0.24 0.81 ± 0.18

Mn mg/L 0.13 ± 0.04 0.13 ± 0.05 0.10 ± 0.02 0.15 ± 0.09 0.13 ± 0.06

BOD5 mg/L 4.6 ± 1.2 4.9 ± 1.0 4.2 ± 0.6 2.3 ± 0.7 2.2 ± 0.7

COD mg/L 12.0 ± 0.9 11.2 ± 1.1 10.8 ± 1.1 11.3 ± 1.5 10.8 ± 1.5

12 12

Reservoir Sand

filtration

Sedimentation

tank Mixing tank

Chlorine

Pump

Station River Receiving tank

Distribution

network

Chlorine

Chlorine Alum/PACl

SURFACE WATER TREATMENT TECHNOLOGY

Conventional treatment

technology & use high

chlorine dosage!!!

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Chlorine is widely used for disinfection & pre-chlorination in WTP DBPs.

DBPs in drinking water serious problem to human health

SECONDARY POLLUTION: THMs

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0.0

1.0

2.0

3.0

4.0

5.0

1 2 3 4 5 6 7 8 9 10 11 12

Ch

lori

ne

(g

/m3)

Month

Dosing Dose

(g/m3)

Chlorine demand (kg/day)

min max Average

At pump station 1 – 2 300 600 450

At receiving tank 2 – 4 600 1.200 900

At clean water

storage tank

0.3 – 0.5 90 150 120

Before pumping to

pipe system

0.5 – 1.0 150 300 225

Total 1140 2250 1695

Chlorine (3-4 mg/L) dose used at Hoa

Phu pump station for pre-chlorination (SAWACO, 2016)

Chlorine dose at Tan Hiep WTP (SAWACO, 2013)

CHLORINE DOSAGE

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TOC reached threshold (4 mg/L) of QCVN 08-MT:2015/BTNMT; TOC is mainly in dissolved form as DOC not removed by

coagulation & filtration; THMFP of raw water at Hoa Phu intake was high (380-420 μg/L)

0

20

40

60

80

100

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr

DO

C/T

OC

(%

)

DO

C, P

OC

(m

g/L)

POC DOC DOC/TOC

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

0

100

200

300

400

500

TOC

(m

g/L)

THM

FP (

g/L)

Month THMFP TOC

ORGANIC & DBPs MONITORING (Dan et al., 2016)

THM standard

16

0

100

200

300

400

500

concentration

(ug/L)

TotalTHMInternationalStandards

THM Standard Limits in Different Countries

Vietnam Standards: (TTHM: 460 μg/L)

QCVN 01/2009 Ministry of Health

- CHCl3: 200 μg/L

- CHCl2Br: 60 μg/L

- CHClBr2: 100 μg/L

- CHBr3: 100 μg/L

17

Compact Surface WTP in Long An province (built by SAWACO)

SURFACE WATER TREATMENT PLANT

Sedimentation tank in Thu Duc WTP

18 18

Technology limits:

• Conventional water treatment (large footprint)

• Effective removal of turbidity, SS, colloids.

• Ineffective to remove TOC & micro pollutants

(EDC, PhCPs, Pesticides,...)

• Use Chlorine as disinfectant THMs formation

• Tap water is not drinkable like in Japan/Europe!

TECHNOLOGY EVALUATION

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Groundwater

Issues

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Arsenic contamination:

+ As = 1 - 46.9 g/L (Long An province)

+ As > 100 g/L (Dong Thap. An Giang

provinces near Cambodia)

(WHO, QCVN 01/BYT ~ 10 g/L for

drinking water) (Thanh et al., 2011)

Map of well distribution & water

exploitation reserve in MD provinces

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(Khanh et al., 2013)

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High As conc. was found at the well with depth of 200-300 m. [16 samples in Long An province exceed the WHO’s standard, 10 ppb] (Thanh et al., 2011)

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Sand

filtration

Sedimentation

tank Mixing tank Pump

Station Tray aeration

Distribution

network Reservoir

Chlorine

Ground

water

Lime

Chlorine

HCMC:

Air contact + sand filtration Aeration tray + sand filtration

GROUNDWATER TREATMENT TECHNOLOGY

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Technology limits:

• Conventional treatment technology (aeration + filtration)

• Effective removal of Fe/Mn, SS.

• Ineffective removal: Ammonia, Arsenic, TOC &

micro pollutants.

• Use of Chlorine as disinfectant (low dosage in MD provinces)

THMs formation.

TECHNOLOGY EVALUATION

• Can not remove Salt from water Need of novel tech.

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Saltwater Intrusion

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• Movement of saline water into freshwater aquifers • Driven by lowering of aquifer freshwater levels

Groundwater Flow Patterns (Ranjan, 2007)

SALTWATER INTRUSION?

Three primary mechanisms:

• Subsurface sea water

movement (large scale

intrusion)

• Seepage from tidal canals &

streams

• Lowering water table (well

extraction)

well

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2nd Week of 4/2016 3rd Week of 4/2016 1st Week of 5/2016 (forecast)

Station Nha Be Cat Lai Ferry Thu Thiem Ong Thin Canal C An Ha canal bridge bridge sewerage

Salinity > 4 - 14 0/00 for all stations (2016)

SALINE INTRUSION IN HCMC

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SALINE INTRUSION: RED RIVER DELTA

Red River Delta (Wikipedia)

• Offshore salinity: 33‰ in dry season &

32‰ in “flood” season.

• Coastal salinity: 25 - 29 ‰.

• Sea level rise 1 m → 1.668 km2 area

waterlogged, affects 1.874.011 people.

• Lack of water in dry season.

(Vu Minh Cat, 2006)

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Bac Lieu & Ca Mau provinces: saline water 20 g/L.

Fruit’s price loss in Ben Tre: 3,000 - 7,000 millions VND.

Drough have worsened the sanility problems in Bac Lieu province (Khanh Hoa, 2016)

SALINE INTRUSION IN MEKONG DELTA

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Damaged in Cu Lao Dung, Soc Trang province,

31,000 ha of rice fields, upland gardens, fruit orchards & shrimp farms.

24,000 ha of rice & sugarcane cultivation

23,000 farming families.

Sugarcane field is destroyed by saltwater intrusion in Cu Lao Dung

district, Soc Trang province in 2015 (Nhan Dan New, 2015)

SALINE INTRUSION

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• A temporary solution

• Unclear quality

• Release plastic wastes

SOLUTION: BOTTLED WATER

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Salt intrusion Lack of freshwater for drinking (Survey from 1001 Fontain Co.)

Best choice

for local

people

• 100% of households already drink 20 L BW

• 70% use 20L BW as their only drinking water source

• Average price = VND 11,000 for 20L ($2.4 cts / liter)

• 14 different brands observed in 1 street!

SOLUTION: BOTTLED WATER

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0

10

20

30

40

50

60

70

80

Price (

thousand V

NĐ

)

Brand

Famous Brand

Local Brand

SOLUTION: BOTTLED WATER

20 L

Bottled Water

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Preventing salt intrusion

by water gate in Hau Giang

Combine rice farming

in rotation with shrimp culture

SOLUTION: DAM & FARMING MODEL

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+ Prevent sea water intrusion, regulate temperature & salinity of pond

water, treat wastewater, clean the air, minimize impact of

environmental pollution.

+ Can combine with aquaculture to bring high economic efficiency

SOLUTION: Mangrove Forest

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Built on the mouth of river reduce coastal salt water intrusion

by constructing offshore sand islands creates a tidal area

with brackish water.

Balance island in Haringvliet, Netherlands (www.dutchwatersector.com, 17/2/2015)

SOLUTION: BALANCE ISLAND

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Water Reservoir: increase water storage, ensure continuously water

supply

Lake Biwa, Japan (www.water.go.jp)

Lake Biesbosch, Netherlands (www.aerostockphoto.com)

SOLUTION: WATER RESERVOIR

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CURRENT DESALINATION TECHNOLOGY

RO is currently the Best Available Technology (B.A.T) for salt removal from water

Reverse Osmosis (RO)

Distillation

Ion exchange

Electro Dialysis

(ED)

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CURRENT DESALINATION TECHNOLOGY

Reverse Osmosis Technology

Advantages:

•Apply for sea water treatment;

•Good treatment performance;

•Large scale system;

•Currently wide application;

Drawbacks:

• High investment/operation cost (OPEX 0.25 $US/m3

, CAPEX 0.45 $US/m3 - Garcia et al., 2013)

• High pressure pump (~100 bar)

• Pretreatment (anti-scaling) required;

• Not effective for very high TDS water;

• Less removal of organics.

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DIRECT CONTACT MEMBRANE DISTILATION

SYSTEM

Only vapor (hydrophobic) pass through hydrophobic membrane

Pore size: 0.45 µm

Flux: 4.1 L/m2.h

Start

Product

28 oC

vapor

Liquid

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TREATMENT PERFORMANCE OF DCMD

No. Parameters

RO Membrane (Lee et al., 2016)

Membrane Distillation (This study)

Effluent Removal Effluent Removal

1 TDS < 129.7 mg/L ~ 99 % < 20 mg/L 99.69 %

2 Chloride - - < 1.4 mg/L 99.93 %

3 Sulfate - - <1.9 mg/L 99.4 %

Concentrated water

• Make sea salt; • Discharge into sea; • Use as draw solution in FO tech.

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• Sea level rise will increase 62-82 cm in 2100 Vietnam

will lose 39% total area of Mekong Delta, 16.8% total area

of Red River Delta;

• Salt conc. increases by 1.2-10 0/00 & moves deeper inland

in the future;

• Water will be scarcity in terms of quality & quantity;

• Advanced water treatment & desalination technologies

must be applied.

• Sustainable water management policy!

CONCLUSIONS

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Thank You!

• HCMUT; Temasek Polytechnic (Singapore) • EPFL (Switzerland); ENSIL (France)

BIOSEP Research Group:

Dr. Bui Xuan Thanh

Ho Chi Minh City University of Technology [C] +84-965-37-6073

[E] bxthanh@hcmut.edu.vn

[I] www.buixuanthanh.com

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