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Forest & Environmental Department Government of Gujarat

Gandhinagar

July 07, 2012

Common Effluent Treatment Plant Performance & Improvement; Issues and Opportunities

CSIR-National Environmental Engineering Research InstituteNagpur

ISO 9001-2008

Dr. S. R. Wate,Director

Seminar onTechnology Solution for Environment Upgradation

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• In India, Small & Medium Scale Enterprises (SMEs) contribute significantly to global economy but face stiff environmental regulations.

• Quantity of wastewater generated from SMEs may not be large, but unfortunately it aggregates to be a major pollution contributor.

• MoEF issued a notification in January, 1991 to ensure compliance of Environmental Standards in polluting industries.

• MoEF formulated 15 point programme for priority action to promote and setup Common Effluent Treatment Plants (CETPs) in clusters of small scale industrial units across the country.

• CETP is listed among 54 polluting industries.

Small & Medium Scale Enterprises

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SMEs do not have wastewater treatment facilities due to the following reasons:

• Huge capital investment for installation of effluent management systems.

• High operation & maintenance expenditure such as skilled manpower, energy, chemicals and laboratory.

• Land availability constraint.

• Lack of awareness and understanding the seriousness of the environmental issues.

Problems in SMEs

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The major objectives of CETP while protecting the environment include, • Achieving ‘economy of scale’ in waste treatment, thereby reducing cost of pollution

abatement for individual industry.

• Minimizing problem of lack of technical assistance and trained personnel.

• Solving the problem of lack of space in the individual industry as centralized facility can be planned in advance to ensure that adequate space is available.

• Homogenization of wastewater for heterogeneous industrial cluster.

• Reducing the problems of monitoring by the regulatory bodies.

• Organizing the disposal of treated effluent & sludge.

• Improving the possibilities of recycle/reuse.

• Improving public image & employer morale.

• CETP is concept of treating effluents by means of a collective effort mainly for a cluster of SMEs units.

• Concept is similar to the Municipal Corporation of cities and towns treating sewage of all the individual houses.

Common effluent treatment plant (CETP)

Objectives of CETP

STATEWISE OPERATIONAL CETPS IN INDIA*Sr. no. State No. of CETP Flow, MLD

1. Andhra Pradesh 3 12.752. Delhi 15 133.23. Gujarat 28** 500.354. Himachal Pradesh 4 1.15. Haryana 1 1.36. Karnataka 9@ -7. Madhya Pradesh 3 0.98. Maharashtra 23# 173.359. Punjab 4 57.7

10. Rajasthan 2 71.1511. Tamil Nadu 36 44.412 Uttar Pradesh 2 70

Total 130 1066.20

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Source: *Central Pollution Control Board Report on Performance Status of Common Effluent Treatment Plants in India, October 2005.

**Gujarat Pollution Control Board, 2010 .@Karnataka Pollution Control Board, 2012. #Maharashtra Pollution Control Board, 2012.

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Approach for designing CETP • Quantity of wastewater generated.

• Characterization of wastewater.

• Inlet feed water quality.

• Wastewater treatability and treatment option.

• Low foot print.

• Mode of disposal of treated effluent.

• Disposal of sludge.

• Recycle/reuse of treated water.

• Modular process, scalable and flexible.

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• Maximum reduction in the effluent quantity generation.

• Environmental compliance.

• Generation of reusable water, if possible revenue generation.

• Minimum operating cost.

What SMEs look for in wastewater managementWhat SMEs look for in wastewater management

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SETTING UP CEPTS WHAT EXPERTS NEED TO LOOK INTO - SELECTION CRITERIA

Life cycle costThis includes installation costs and operation costs, which are usually capitalized over the life of the project to provide a common basis for comparing different options.

Cost-effectiveness

Expressed as a unit cost to provide a basis for comparing different options (Rs./m3). For example, economies of scale often reduce the unit cost of treating wastewater but are not necessarily cost-effective if wastewater flows are not high enough to allow the technology to perform optimally.

ReliabilityMeasure of how well a system performs in relation to expectations without breakdowns or failure to treat wastewater to meet water quality objectives. Reliability also is associated with simplicity of operation and ease of maintenance. Reliable systems that require highly skilled operators and careful maintenance would be less appropriate.

Simplicity• Simplicity of operation and ease of maintenance. This is highly desirable for

CETPs designed for SMEs.

• Contd…

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PerformanceThis is usually measured in terms of percent removal or may be expressed as typical treated effluent concentrations required to meet water quality objectives by a particular treatment option or combination of options.

Ability to meet water quality objectivesThis is a primary screening criterion. Any system that is not able to meet water quality objectives does not need to be considered any further.

Adaptability to change in influent qualityThis is a very important criterion for CETPs designed for SMEs because wastewater quality tends to be more variable than for conventional municipal wastewater treatment.

Performance dependent on pretreatmentThis may or may not be a significant consideration. All other things being equal, however, options that can meet water quality objectives without pretreatment would be favored.

Adaptability to varying flow rate. This is an important criterion for CETPs designed for SMEs, if the industries involved have highly varying flow rates. Contd…

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Adaptability to upgradingThis may or may not be a significant consideration for CETPs designed for SMEs, depending on local conditions.

Ease and availability of major equipmentThis is a primary consideration in the design. If the equipment is not available locally or regionally, or is not available at a price that is reasonable due to high transportation costs, the option can be excluded from further consideration.

Post installation service/chemical deliveryGenerally, systems that minimize post installation service for CETPs are desirable. If chemicals are used, it is critical that they be readily available. 

Personnel skill levelGenerally, options that require low personnel skill levels are preferred for CETP in SMEs to options that require a high skill level. This generally goes along with simplicity of operation and ease of maintenance.

Contd…

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Energy utilizationGenerally, options that require no or low energy are preferred for CETPs designed for SMEs to those that are energy intensive.

Residue production and cost of disposalThis is a major consideration for CETPs in design. Sludges are sufficiently contaminated that they are not suitable for land application. In this situation, options that minimize sludge production are desirable. 

Potential for effluent use/reuseHigh potential for effluent use or reuse would be a favorable characteristic for CETPs designed for SMEs.

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Wastewater characteristics

Wastewater quality Treatment options

Low TDS and low BOD Low organic Chemical treatmentLow TDS and high BOD Organic effluent Anaerobic + aerobic treatmentLow TDS and high COD Highly organic Chemical oxidation by hydrogen peroxide or

ozone or sodium hypochloriteChemical + biological treatment

Refractory Chemical oxidation + biological treatmentHigh TDS Inorganic salts Solar evaporation

Forced evaporation (after separation of volatile organic matter)Membrane separation

High TDS and high COD Highly organic effluent Incineration (based on calorific value) +Secure landfill of incineration ash

Waste is not easilybiodegradable but toxic

Thermal DecompositionChemical oxidation (hydrogen peroxide, ozone, etc.)Evaporation + Secured landfill

Waste is not toxic but mostlyinorganic salts

Chemical treatment (recovery, precipitation etc.)Evaporation + secured landfill of evaporated residue

Selection of technology based on influent quality for CETP

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FunctionalPerformance Expressed in removal of BOD/COD, heavy metals, organic micro-pollutants,

pathogens and nutrients.Adaptability Possibility for implementation on different scales, increasing/decreasing capacity,

anticipated changes in legislation, etc.Durability Lifetime of installation.Flexibility Sensitivity of the process in terms of toxic substances, shock loads, seasonal

effects, etc.Maintenance required

Frequency, costs and time needed for maintenance.

Reliability Sensitivity of the process in terms of repairs and maintenance.

Economic Affordability Costs in relation to national/regional budget. Foreign exchange required in relation

to national/regional foreign exchange requirements.Costs Net present value of the investment costs (specified for land, materials, equipment

and labour), maintenance costs.Cost effectiveness

Performance relative to costs.

Labour Number of employees needed for operation and maintenance. Willingness to pay

The amount of money spent by users in relation to their total budget for improvised treatment.

Sustainability criteria for assessment of treatment technologies

Contd…

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Resource utilizationEnergy Energy used, produced and ‘lost’ during installation, operation of the

wastewater treatment system. Energy ‘lost’ indicates the amount of energy no longer available due to emissions on waste disposal. Eg. sustainable energy sources.

FunctionalLand area The total land area required. The feasibility of integrating the wastewater

treatment system (partly) in green areasNutrients Amount of nutrients suitable for reuse.Organic matter Amount of organic matter recycled through sludge reuse. Amount of

organic matter recycled through biogas production.

SocialInstitutional requirements

Effort needed to control and enforce existing regulations. Indication of embedding of technology in policymaking.

CulturalAcceptance Indication of the cultural changes and impacts: convenience and

compatibility with local ethics.Expertise Number of engineers needed for installation and operation. Indication

whether a system can be designed and built or can be repaired, replicated and improved locally (in the country) or only by specialized manufacturers.

Stimulating sustainable behavior

Possibilities for technical stimulation of sustainable behavior and participation by the end user.

Contd…

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Inlet effluent quality and discharge Standards for CETPParameters Inlet effluent quality

pH 5.5 - 9.0

Temperature (oC) 45.0

Oil and grease 20.0

Cyanide 2.0

Ammoniacal-N 50.0

Phenolic compounds 5.0

Hexavalent Chromium 2.0

Total chromium 2.0

Copper 3.0

Nickel 3.0

Zinc 15.0

Lead 1.0

Arsenic 0.2

Mercury 0.01

Cadmium 1.0

Selenium 0.05

Fluoride 15.0

Boron 2.0

All values are expressed in mg/l, except pH and temperature.Source: The gazette of India: Extraordinary- Part II- Sec.3 (i) pp10 Dt. 27th Feb 1991

Parameters Discharge Effluent Standards into ISW

pH 5.5-9.0

SS 100

TDS 2100

COD 250

BOD (3d, 27°C) 30

Oil & Grease 10

Chlorides 600

Sulphates 1000

Phosphates 5

Ammoniacal-N 50

Fluoride 2.0

Arsenic 0.2

Cyanide 0.2

Mercury 0.01

Iron 3

Manganese 2

Chromium 2

Copper 3

Zinc 5

Nickel 3

Lead 0.1

Selenium 0.05

All values are expressed in mg/l, except pH ISW-Inland Surface Waters.

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CETP :GETP, Palsana (Textile industry)

Parameter Equalized effluent

Secondary effluent

Discharge Standard into

ISW

pH 7.8-8 7.9-8.2 6.5-9.5

SS 88-140 12-22 100

COD 678-832 84-100 100

BOD 272-310 26-30 30

TDS 1632-2036 1604-2036 2100

CETP: Punjab (Electroplating industry)

Parameter Equalized effluent

Secondary effluent

Discharge Standard into

ISW

pH 2.1 7.5 6.5-9.5

SS 36-48 26 100

COD 368-376 224 250

BOD 48-52 24 30

TDS 12720-12820 12684 2100

CETP :Tirupur (Textile industry)

Parameter Equalized effluent

Secondary effluent

Discharge Standard into

ISW

pH 7.1-8.6 8.2-8.6 6.5-9.5

SS 120-675 26-62 100

COD 550-950 270-475 250

BOD 210-342 92-210 30

TDS 6010-6644 6534-6840 2100

CETP:Ankaleshwar (Heterogeneous effluent Dye & dye intermediates, Pharm., textiles

Parameter Equalized effluent Tertiary effluent

Discharge Standard into

ISW

pH 0.38-0.56 7.7-7.88 5.5-9.0

SS 1776-1864 100-132 100

COD 5107-8373 382-395 250

BOD 2200-2400 40-50 30

TDS 68200-68830 7532-11836 2100

All values are expressed in mg/l, except pH; ISW-Inland Surface Waters.

Performance of CETPs

Contd…

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CETP;Ranipet (Tannery effluent)

Parameter Equalized effluent

Tertiary effluent

Discharge Standard into

ISW

pH 7.7-8.2 6.6-6.7 5.5-9.0

SS 2015-2459 45-50 100

COD 7480-9898 122-130 250

BOD 2545-3068 10-12 30

TDS 19856-2115 13209-13245 2100All values are expressed in mg/l, except pH.ISW-Inland Surface Waters.

CETP:Jeedimetla (Heterogeneous effluent, pharmaceuticals & textiles etc)

ParameterEqualized effluent

Tertiary effluent

Discharge Standard into

ISW

pH 8.8-8.3 7.9-8.0 5.5-9.0

SS 752-848 86-96 100

COD 10200-14400 876-960 250

BOD 4050-5380 68-88 30

TDS 35368-39218 15063-16800 2100

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Performance Treatment option Efficiency (%)High Chemical precipitationbio-oxidationchemical

precipitationsand filtration activated carbon adsorption

BOD : 84-93COD : 80-90

SS : 77-98Chemical precipitationbio-oxidationsand filtrationdual media filtrationChemical precipitation (3 stage)media filtrationactivated carbon adsorptionOzonationbio-oxidationsand filtrationactivated carbon adsorption.

Moderate Electro-coagulationbio-oxidationchemical precipitationsand filtrationactivated carbon adsorption.

BOD : 68-79COD : 60-73SS : 64-78

Low Bio-oxidationsand filtrationdual media filtrationactivated carbon adsorption BOD : 56-70

COD : 48-65SS : 52-74Chemical precipitationsand filtrationactivated

carbon adsorptionCatalytic oxidation BOD : 24-25

COD : 21-23SS : 56-60

Performance of primary, secondary and tertiary treatment

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40 50 60 70 80 90 100

RO II

RO III

RO IV

Permeate recovery, %

Stag

es o

f rev

erse

osm

osis

65 80

84 92

85 97

Permeate recovery in 2-4 stage of reverse osmosis system

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Selection of an appropriate treatment option for optimum performance

with due consideration to investments requires comparison of different

options with respect to certain criteria.

Parameter governing selection of wastewater treatment options Capital cost O&M costs Treatment performance Water recovery Treatment time Foot print Sludge production Reject generation.

Ranking of technology options

ISSUES & CONSTRAINTS IN CETP OPERATIONS

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• Consistency in compliance to the prescribed standards by the CETPs.

• Existing treatment schemes are unable to handle ever-increasing hydraulic load, new pollutants, stringent regulatory norms.

• Improper technological combination for wastewater treatment is discouraging water reuse and recycling.

• Poor management of treatment units.

• No separate treatment units to deal with hazardous and toxic effluents.

• Dismal percentage of water reuse practice in industries.

• Lack of access to capital investments and working capitals.

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AREAS FOR IMPROVEMENT IN CETPS

Reduce pollutant loads discharged into the receiving aquatic environment through adoption of recent developments in the areas of effluent management systems. 

Development programmes for water and chemicals recovery through adoption of advanced oxidation and membrane filtration process.

Utilization of sludge/solids as raw material for construction activities after ascertaining its properties.

Induction of energy efficient technologies particularly in oxygen transfer in activated sludge process (diffused aeration systems), gas transfer, solids separation and thermal decomposition .

Replacement of major energy intensive electrical components with high efficiency motors for aerators, blowers, pumps and centrifuges eg variable-frequency drives.

Installation of SCADA (supervisory control and data acquisition) based systems for better operational and management control of the CETPs.

Combined heat and power (CHP) or cogeneration as an option to reduce solids and generate energy/power (eg. turbines, micro-turbines, internal combustion/reciprocating engines, steam engines/turbines, and fuel cells). 

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OPPORTUNITIES IN CETPS

• Development and optimization of new methods and process configurations for resource effective wastewater treatment.

• Development of equipment for wastewater treatment and separation technology .

• Development of new methods process configurations for water production from wastewater.

• Development of low cost and wastewater specific membranes for water reuse/reclamation.

• Improvements in membrane performance including the development of lower pressure membranes (e.g. reduce fouling, increase flux, improve rejection, increase integrity, increased longevity,etc.).

• Concentrate/reject treatment and disposal strategies for zero liquid discharge schemes.

Contd…

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• Development of energy efficient advanced oxidation for organic and recalcitrant compounds in wastewater.

• Alternative disinfection systems for wastewater including ozone, UV, chlorine dioxide and gaseous/liquid chlorine.

• Improvements and cost reductions in thermal processes for chemicals and energy recovery such as evaporation and plasma incineration.

• Development of treatment options/packages for country specific wastewaters.

• Delineation of treatment option/schemes to reduce energy consumption and hazardous wastes disposal.

• Development of instrumentation package for automation of the treatment package and bringing down cost of components.

• Strategies to speed up the development and adoption of new technologies.

• Develop best management practice for industrial customers.

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• A worldwide trend toward acceptance of the concept of reuse is currently observable, as water shortages have intensified. This should aim at increasing in the use of multiple water reuse practices.

• New technologies offering significantly higher removal rates are being designed and implemented. Membrane technologies, which were formerly restricted to water desalination applications, are now being tested for the production of high quality water for indirect potable reuse, and are expected to become the predominant treatment technologies in the near future.

• In the field of sludge reclamation and reuse technologies, increased attention is being devoted to the production of sludge that is clean, has less volume and can be safely reused. Developments in this area have been slower than in the field of wastewater treatment, but a number of new technologies have emerged, including high-solids centrifuges, plasma incinerators. Sludge land filling and incineration continue to decrease due to stricter regulations and increased public awareness. The current trend should be in the direction of more reuse opportunities. Volume reduction with a view to decreased disposal requirements is also an ongoing concern.

Conclusion