UASB TECHNOLOGY FOR SEWAGE TREATMENT IN INDIA: EXPERIENCE, ECONOMIC EVALUATION AND ITS POTENTIAL IN OTHER DEVELOPING COUNTRIES

Abstract

It’s nearly two decades since UASB (Upflow Anaerobic Sludge Blanket) concept for sewage (municipal wastewater) treatment was started in India and today it has taken an edge over the other developing countries having similar climatic conditions in the use of this technology. At present, about 23 full-scale UASB plants are in operation at various places in India with total installed capacity of about 9,85,000 m 3 /day (985 mld) and about 20 number are in pipeline which are likely to be commissioned within next 3-4 years. With financial assistance from international funding agency, the National River Conservation Directorate (NRCD) under the Ministry of Environment & Forests (MoEF), Government of India (GoI), formulated and launched a comprehensive action plan project for conservation of the river Yamuna under which 16 UASB sewage treatment plants (STPs) were commissioned in the period of 1999-2002. Experience shows that the present UASB reactor design and construction is quite different from the very first module of 5 mld treatment capacity that was constructed as a demonstration plant at Kanpur, India under the Ganga Action Plan (GAP) in late 80’s. The discrepancies in the initial UASB plants were recorded and now a new breed of UASB reactor is available with respect to the design, operation and maintenance, and materials of construction. Initially, most of the UASB plants were provided with final polishing ponds as post-treatment unit, but now other options for the same are being explored to meet the stringent regulations. This paper reviews the overall implications of UASB technology in India. Institutional and technical aspects with special reference to the Yamuna Action Plan (YAP) are presented. It also presents the potential of UASB technology in other developing countries with its future within India as well based on the evaluation of life cycle cost (LCC). Other sewage treatment technologies were also included while evaluating LCC. The LCCE can be used as a tool for selecting appropriate technology under similar climatic and economic conditions in other developing countries. LCC supports that UASB as one of the most favourable methods of wastewater treatment from all aspects.