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Recycle and Reuse of ‘Difficult to
Treat’ industrial waste water
Pinaki Bhadury
“By 2030, India will face 50% water supply shortage”
- Report by The 2030 Water Resource Group, 2009
Picture source : Google Images
Industries Shut Down Due to Water Shortage!
Wed, 29 Aug 2012 10:50:42 GMT | By Business Line Water shortage leaves industry parched Chennai: A slowing economy and a crippling power crisis have given industry sleepless nights. Adding to its woes is the poor south-west monsoon, which threatens to leave water-intensive manufacturing units high and dry.
Companies that have invested on rain water harvesting and other water saving systems are managing to tide over the shortfall. But, production at a few manufacturing facilities has been hampered. For instance, Southern Petrochemicals Industries Corporation (SPIC) has completely stopped production at its Tuticorin plant, in southern Tamil Nadu, as there is no water supply. The company said production has been suspended due to reasons beyond its control and that "production would resume once the water supply is restored." Last month, Grasim Industries suspended production at its staple fibre plant in Nagda (Madhya Pradesh); also, output at its chlor-alkali plant was reduced by half. However, with the delayed onset of the monsoon, work at these plants resumed gradually. Alkyl Amines Chemicals too faced production constraints with the Maharashtra Industrial Development Corporation restricting water supply to various industrial units in Kurkumbh. Water availability has improved at Kurkumbh, and the company's operations have been normalised. But industrial units in the area may still not be out of the woods.
Future Water Demands
3100
4500 3500
800
1500
100
700 600
900
2800
0
1000
2000
3000
4000
5000
6000
7000
8000
Exisiting Withdrawals 2030 Withdrawals Basins with Deficits Basins with Surplus Exisiting accessible reliable sustainable
supply
Bill
ion
cu
m
Water Demand, Supply, Resources & Availability
Municipal & Domestic Industry Agriculture
6900
4500
- 40%
Surface Water
Ground Water
9%
Source: Recreated chart from 2030 Water Resource Group Report – “Charting our Water for Future 2010”
• Global demand for fresh water will increase from 4500 to 6900 Billion M3 by 2030
• All the fresh water resources taken together has a capacity of 4500 Billion M3 , creating a shortage of 2700 Billion M3 or 40% of the demand
• India which has a shortage of fresh water resources, will be worst hit with maximum deficit of 50% of its demand unless steps are taken for water conservation
Water Demand Trends
Source: 2030 Water Resource Group Report – “Charting our Water for Future 2010”
Water – Scarcity and Pollution
India’s industrial zones are located in the water stressed regions
Da
ta s
ou
rce:
CSE
– ‘E
xcre
ta M
att
ers”
Waste Water Generation and its Use
18 Billion M3 a year
4.2 Billion M3
13.8 Billion M3
• India generates 18 Billion M3 of waste water every year
• Not all waste water from Domestic and Industry is treated
• Only 30% & 7% of sewage from Tier I & II cities is treated
• Rest is discharged untreated in to rivers and fields
• Untreated water is contaminating surface and ground water resources
• Treatment and Recycle will • Save precious natural resources from
pollution • Generate additional 32 Billion M3 water
for reuse annually both for industry and domestic sectors
Source: Central Pollution Control Board
Waste Water Recycle and Reuse can be new water resource and help reduce water stress
Industrial Effluents – Heavy Metals
• Study shows that some of the major industries discharge dangerous heavy metals which are considered to be highly toxic – Cr, Ni, Cd, Zn, Pb, Cu
• This leads to contamination of ground as well as surface water that leads to long lasting health problems and threatens the aquatic life of the marshy lands and landfall in to the sea
0
10
20
30
40
50
60
Engineering Paper Mill Fine Chemicals Dyes
mg/
litre
Heavy Metals in Industrial Effluent
Cr Cd Ni Zn Cu Pb Fe
A study conducted of the industrial belt in
Taloja, Navi Mumbai showed dangerous
levels of heavy metals being discharged in
the effluents from the industries in the
area
Source : “Toxicity Study of Heavy Metals Pollutants in Waste Water” by Ram S Lokhande
Dangerous Metals in Effluents
Water – Scarcity and Pollution • India’s water source is limited to 1122
Billion M3
• Of this 688 Billion M3 is used for
Agriculture
• Where as the industrial demand at 17
Billion M3 is rising by 35% year on year
• The only way industries can meet their
demand is through waste water recycle and
reuse
• Zero Liquid Discharge (ZLD) provides
maximum potential for water reuse
Industrial Effluent Pollutants Almost all industrial manufacturing processes generate effluents that are highly polluting
Major Industrial Effluent Pollutants
Refineries
• Toxic Hydrocarbons • Oils and grease with high BOD and COD
Battery Manufacturing
• Lead • Heavy Metals • Acids
Textiles
• Dye, Color • Surfactants • Phenols • Heavy Metals (e.g. Cr, Co, Zn, Pb, or Ni) • Halogens • Amines
Major Industrial Effluent Pollutants
Chemical & Pharma
• Organic Solvents • Methanol • Toluene • Hexane • Branched chain fatty acids & Ketone
Paints & Inks
• Heavy Metals • Solvents
Pulp & Paper
• High BOD & COD • Heavy Metals • Inflammable Solvents
Major Industrial Effluent Pollutants
Metals
• Low pH Acid Waste • Heavy Metals • Cyanide waste, • Paint waste
Beverages & Sugar
• Spent Wash containing Methanol
• High BOD & COD
Leather & Tanning
• BOD
• COD
• Sulphate,
• Chromium
• Oil & Grease
Industrial Wastewater Treatment Methods & Technologies
Physio/Chemical methods
• Screening
• Centrifuging
• Filtration
• Sedimentation
• Flotation
• Solvent extraction
• Ion exchange
• Reverse osmosis
• Adsorption
• Oil / water separators
Separation Techniques
• Ion exchange
• Evaporation
• Molecular filtration
• Solvent extraction
• Electrodialysis
EVAPORATORS
ION EXCHANGE COLUMN ELECTRODIALYSIS
MOLECULAR FILTRATION
Biological Methods
• Standard Processes
– Activated sludge
– Trickling filter
• Submerged fixed film (bio film) reactors
• Sequencing Batch Reactors
• Anaerobic treatment
– Digester
– Up flow anaerobic sludge bed (UASB) reactors
ATTACHED GROWTH TREATMENT
UASB ANAEROBIC TREATMENT
DIGESTER
ACTIVATED SLUDGE PROCESS
Industrial Applications All industries can use a combination of these technologies to safely treat and
reuse the effluent in their process
Recycle of Textile Effluent • Recycling of Dye bath waste water applied for those dyes (direct, disperse, acid and basic) which are not
decomposed during dyeing
• Reconstitution of dye bath gives saving of water, dyes and auxiliaries
Parameter Dyeing Dyeing & printing
BOD5 (mg/l) 200-570 300-480
COD (mg/l) 640-1200 880-1130
TSS (mg/l) 320-940 200-450
TDS (mg/l) 1280-1540 1000-1900
Chloride (mg/l) 400-750 90-1100
Chromium (mg/l) 0.5-3.6 1.5-12.6
O & G (mg/l) 17-32 11-40
Copper (mg/l)
0.4-0.5
0.10
The Journal of Cotton Science 11:141–153 (2007)
Wash Water Collection Tank
Dye Bath Waste Water
Textile Dyeing Process
Flocculation Tank
Primary Clarifier
Biological Treatments
Secondary Clarifier
Filtration & Ozonation
RO
stage I
RO
stage II Filtration Bed
Nan
o
Filtration
Evaporators
Crystallizers
Zero Liquid Discharge System for Molasses Based Distilleries
Parameter Direct Spent Wash
Bio-methanated
BOD5 (mg/l) 40000–60000 5000–8000
COD (mg/l) 80000–100000 20000–25000
TSS (mg/l) 60000–120000 35000–40000
pH 4–5.3 7–7.5
Distillery Spent Wash
Bio- Methanation
Concentration By Evaporation/RO
Reusable Condensate
Water
Concentrate
Spray Dryer Rotary Dryer
Powder/Mixed Fuel
Mixed with Rice Husk/ Bagasse
Air Heater Air Heater
Boiler
Turbine Power
Generation Back Pressure/ Bleed Steam for Process use
Manufacturing facility effluent
Chemical Reaction Tank
Equipment wash down water
Chemical Dosing
Clarifier Settling
Reused for paste makeup & for acid dilution in the electrolyte makeup area
Solid collection
The solids should be returned to paste makeup with some blow down
Stream with Oil and Grease
Common Collection Sump
Oil & Grease Removal Treatment
Metal recovery from Electroplating effluent
Chemical Reaction Tank
Chemical Dosing
Clarifier Settling
Media Filtra- tion
pH Correction
Collection Tank
Ion Exchange Units
Reuse of Waste water in Industry
Recovery of metals is accomplished by alkaline, sulfide, phosphate, or carbonate precipitation.
If the wastewaters contain fluoride, then use of lime as the precipitating agent.
For Cr+6 addition of (slightly soluble) FeSO4 will effect sulfide precipitation of Metals, and at the same time reduce the hexavalent chrome to Cr+3 which is far less toxic.
If the pH is maintained between 8.0 and 9.0 during this process, then the trivalent chrome will be precipitated as the hydroxide
Addition of Ferrous Sulfide
pH Adjustment
Slow Mixing
Sedimentation
Filtration
Ion exchange can then be employed to reduce the concentrations of these substances to non-detect levels
The product water can then be returned to the process for use as either plating bath makeup water or rinse makeup water.
Metal recovery from Electroplating effluent
Treated
Water
Feed Tanks Effluent
Feed
It is common in most refineries to collect all process wastewaters and to combine them into a single wastewater.
Dissolved Air Flotation
API Separator
Equalization basin
Sludge Recycle Sludge Wastage
Activated Sludge Process
Aeration basin Clarifier settling
Petroleum Refinery Effluent Treatment
Effluent
Equalization Dissolved Air Flotation (DAF)
MBBR Biological Reactor
Clarifier
Waste
Effluent
Sludge Waste & Recycle
Chemical Reaction & Precipitation
Advance Filtration
Micro Nutrients Dosing
Chemical Dosing
pH control Dosing
For Disposal Or Recycle
Chemical & Pharma Effluent Treatment
Disinfection Pre-treatment
Primary Activated sludge Clarifier Chemicals
Sedimentation Sand filter
MF/UF Disinfection
Reverse Osmosis Disinfection/Oxidation
Reverse Osmosis Disinfection/ Oxidation
Water Reuse Treatment Trains
Screening MBR Disinfection
Raw Sewage
