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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. ISO 9001-2008. Dr. S. R. Wate, Director.
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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 ISO 9001-2008 Dr. S. R. Wate, Director CSIR-National Environmental Engineering Research Institute Nagpur
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 SMEsmay 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 programmefor 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.
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.
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.
Statewise operational CETPS in India* 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.
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.
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.
Setting up cepts what experts need to look into - selection criteria • Simplicity of operation and ease of maintenance. This is highly desirable for CETPs designed for SMEs. • 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 Contd…
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 highly varying flow rates. Contd…
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…
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.
Sustainability criteria for assessment of treatment technologies Contd…
Performance of CETPs All values are expressed in mg/l, except pH; ISW-Inland Surface Waters. Contd…
All values are expressed in mg/l, except pH. ISW-Inland Surface Waters.
Permeate recovery in 2-4 stage of reverse osmosis system 85 97 Stages of reverse osmosis 84 92 65 80 Permeate recovery, %
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.
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.
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).
Opportunities in CETPs Contd… • 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.
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.
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 ratesare being designed and implemented. Membrane technologies, whichwere formerly restricted to water desalination applications, are now being tested for the production of high qualitywater for indirect potable reuse, and are expected to become the predominant treatment technologiesin the near future. • In the field of sludge reclamation and reuse technologies, increased attention is being devoted to theproduction of sludge that is clean, has less volume and can be safely reused. Developments in this area havebeen 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 publicawareness. 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.