Common Effluent Treatment Plant
Performance & Improvement; Issues and Opportunities
Seminar on
Technology Solution for Environment Upgradation
Forest & Environmental Department
Government of Gujarat
Gandhinagar
July 07, 2012
Dr. S. R. Wate,
Director
CSIR-National Environmental Engineering Research Institute
Nagpur
ISO 9001-2008
1
Small & Medium Scale Enterprises
•
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.
2
Problems in SMEs
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.
3
Common effluent treatment plant (CETP)
•
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.
Objectives of CETP
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.
4
STATEWISE OPERATIONAL CETPS IN INDIA*
Sr. no.
State
No. of CETP
Flow, MLD
1.
Andhra Pradesh
3
12.75
2.
Delhi
15
133.2
3.
Gujarat
28**
500.35
4.
Himachal Pradesh
4
1.1
5.
Haryana
1
1.3
6.
Karnataka
9@
-
7.
Madhya Pradesh
3
0.9
8.
Maharashtra
23#
173.35
9.
Punjab
4
57.7
10.
Rajasthan
2
71.15
11.
Tamil Nadu
36
44.4
12
Uttar Pradesh
2
70
130
1066.20
Total
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.
5
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.
6
What SMEs look for in wastewater management
• Maximum reduction in the effluent quantity generation.
• Environmental compliance.
• Generation of reusable water, if possible revenue generation.
• Minimum operating cost.
7
SETTING UP CEPTS WHAT EXPERTS NEED TO LOOK INTO - SELECTION CRITERIA

Life cycle cost
This 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.

Reliability
Measure 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…
8

Performance
This 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 objectives
This 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 quality
This 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 pretreatment
This 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
Contd…
highly varying flow rates.
9

Adaptability to upgrading
This may or may not be a significant consideration for CETPs designed for SMEs,
depending on local conditions.

Ease and availability of major equipment
This 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 delivery
Generally, systems that minimize post installation service for CETPs are desirable. If
chemicals are used, it is critical that they be readily available.

Personnel skill level
Generally, 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…
10
 Energy utilization
Generally, 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 disposal
This 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/reuse
High potential for effluent use or reuse would be a favorable characteristic for CETPs
designed for SMEs.
11
Selection of technology based on influent quality for CETP
Wastewater
characteristics
Wastewater quality
Treatment options
Low TDS and low BOD
Low organic
Chemical treatment
Low TDS and high BOD
Organic effluent
Anaerobic + aerobic treatment
Low TDS and high COD
Highly organic
Chemical oxidation by hydrogen peroxide or
ozone or sodium hypochlorite
Chemical + biological treatment
Refractory
Chemical oxidation + biological treatment
High 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 easily
biodegradable but toxic
Thermal Decomposition
Chemical oxidation (hydrogen peroxide,
ozone, etc.)
Evaporation + Secured landfill
Waste is not toxic but
mostly
inorganic salts
Chemical treatment (recovery, precipitation
etc.)
Evaporation + secured landfill of evaporated
residue
12
Sustainability criteria for assessment of treatment technologies
Functional
Performance
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.
Contd…
13
Resource utilization
Energy
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.
Functional
Land area
The total land area required. The feasibility of integrating the wastewater
treatment system (partly) in green areas
Nutrients
Amount of nutrients suitable for reuse.
Organic matter
Amount of organic matter recycled through sludge reuse. Amount of
organic matter recycled through biogas production.
Social
Institutional
requirements
Effort needed to control and enforce existing regulations. Indication of
embedding of technology in policymaking.
Cultural
Acceptance
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…
14
Inlet effluent quality and discharge Standards for CETP
Parameters
pH
Inlet effluent quality
5.5 - 9.0
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
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
Phosphates
5
Copper
3.0
Ammoniacal-N
50
Nickel
3.0
Fluoride
2.0
Zinc
15.0
Arsenic
0.2
Lead
1.0
Cyanide
0.2
Arsenic
0.2
Mercury
0.01
Mercury
0.01
Iron
3
Cadmium
1.0
Manganese
2
Selenium
0.05
Chromium
2
Fluoride
15.0
Copper
3
Zinc
5
Boron
2.0
Nickel
3
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
Lead
0.1
Selenium
0.05
All values are expressed in mg/l, except pH
ISW-Inland Surface Waters.
15
Performance of CETPs
CETP :Tirupur (Textile industry)
CETP :GETP, Palsana (Textile industry)
Equalized
effluent
Secondary
effluent
Discharge
Standard into
ISW
pH
7.1-8.6
8.2-8.6
6.5-9.5
100
SS
120-675
26-62
100
84-100
100
COD
550-950
270-475
250
272-310
26-30
30
BOD
210-342
92-210
30
1632-2036
1604-2036
2100
TDS
6010-6644
6534-6840
2100
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
COD
678-832
BOD
TDS
Parameter
Parameter
CETP: Punjab (Electroplating industry)
CETP:Ankaleshwar (Heterogeneous effluent
Dye & dye intermediates, Pharm., textiles
Equalized
effluent
Secondary
effluent
Discharge
Standard into
ISW
pH
2.1
7.5
6.5-9.5
SS
36-48
26
COD
368-376
BOD
TDS
Parameter
Parameter
Equalized
effluent
Tertiary effluent
Discharge
Standard into
ISW
pH
0.38-0.56
7.7-7.88
5.5-9.0
100
SS
1776-1864
100-132
100
224
250
COD
5107-8373
382-395
250
48-52
24
30
BOD
2200-2400
40-50
30
12720-12820
12684
2100
TDS
68200-68830
7532-11836
2100
All values are expressed in mg/l, except pH;
ISW-Inland Surface Waters.
Contd…
16
CETP:Jeedimetla (Heterogeneous effluent,
pharmaceuticals & textiles etc)
CETP;Ranipet (Tannery effluent)
Equalized
effluent
Tertiary
effluent
Discharge
Standard into
ISW
pH
8.8-8.3
7.9-8.0
5.5-9.0
pH
SS
752-848
86-96
100
COD
10200-14400
876-960
BOD
4050-5380
TDS
35368-39218
Parameter
Tertiary
effluent
Discharge
Standard into
ISW
7.7-8.2
6.6-6.7
5.5-9.0
SS
2015-2459
45-50
100
250
COD
7480-9898
122-130
250
68-88
30
BOD
2545-3068
10-12
30
15063-16800
2100
TDS
19856-2115
13209-13245
2100
Parameter
Equalized
effluent
All values are expressed in mg/l, except pH.
ISW-Inland Surface Waters.
17
Performance of primary, secondary and tertiary treatment
Performance
Treatment option
High
Chemical precipitationbio-oxidationchemical
precipitationsand filtration activated carbon
adsorption
Efficiency (%)
BOD : 84-93
COD : 80-90
SS : 77-98
Chemical precipitationbio-oxidationsand
filtrationdual media filtration
Chemical precipitation (3 stage)media
filtrationactivated carbon adsorption
Ozonationbio-oxidationsand filtrationactivated
carbon adsorption.
Moderate
Electro-coagulationbio-oxidationchemical
precipitationsand filtrationactivated carbon
adsorption.
Low
Bio-oxidationsand filtrationdual media
filtrationactivated carbon adsorption
Chemical precipitationsand filtrationactivated
carbon adsorption
Catalytic oxidation
BOD : 68-79
COD : 60-73
SS : 64-78
BOD : 56-70
COD : 48-65
SS : 52-74
BOD : 24-25
COD : 21-23
SS : 56-60
18
Stages of reverse osmosis
Permeate recovery in 2-4 stage of reverse osmosis system
RO IV
85
RO III
84
RO II
40
97
65
50
60
92
80
70
80
90
100
Permeate recovery, %
19
Ranking of technology options

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.
20
ISSUES & CONSTRAINTS IN CETP OPERATIONS
• 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.
21
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).
22
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…
23
•
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.
24
Conclusion
•
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.
25