Description

0 INTRODUCTION 

Urbanization has empowered the migration of people from villages to the urban areas in India. With rapid growth in urbanization, a number of environmental issue have emerged. In urban areas, water is tapped from rivers, streams, wells and lakes for domestic and industrial purposes, Bhagat (2012). Almost 80% of the water supplied for domestic pupose, comes back as wastewater. In most of the places in India, untreated wastewater is left out which either sinks into the ground and act as a major pollutant source for ground water or is discharged into the natural streams causing pollution in downstream areas, Bhagat et al.(2009). A major problem in urbanized areas is the collection, treatment and disposal of residential wastewater, Mukherjee et al.(2015). Because huge volume of sewage is generated in many cities/ towns and the waste is not treated adequately and disposed off in the open drains which flows downstream and mixes in water bodies. The intensive use of ground water and the large quantity of wastewater generation in modern time often pose a threat to ground water quality. Therefore it is very much essential to treat the domestic wastewater in proper manner by installation of sufficient capacity of sewage treatment plants (STPs) to prevent the contamination of ground water and surface water bodies etc. Majorly it was observed that, cities have no proper sewerage network to collect entire sewage generated. Due to insufficient collection system major part of untreated sewage discharged directly/indirectly in open drains which lead to contamination of surface water bodies. Release of untreated sewage is single most critical cause for pollution of surface and ground water since there is a huge gap between generation and treatment technology for domestic wastewater in India. The problem is not only of insufficient treatment capacity but also operation and maintenance of treatment plants. Several sewage treatment plants are established under centrally financed National River Action Plan, CPCB (2009). However, their operation and maintenance is generally not up to the mark. Huge investment is done on establishing sewage treatment plants and if not properly operated, the entire exercise becomes wortheless. In order to ensure that these STPs function properly it is necessary to carry out study to evaluate their performance and identify main problems. The quality of water resources defines the quality of life but the contrary water crisis has been the major environmental concern from the past decade. Water resources are getting contaminated by various factors. Among various issues in India, the major environmental issue is water pollution. The largest source of water pollution in India is untreated sewage, Changte M.K. (2015). Other sources of pollution include agricultural runoff and unchecked small scale industry. Most rivers, lakes and surface water in India are highly contaminated. The pressure of increasing population, growth of industries, urbanization, energy usage, deforestation, mining, untreated effluent discharge from industries and municipalities, use of non-biodegradable pesticides, use of chemical fertilizers instead of organic manures, lack of environmental awareness, lack of implementation of environmental rules and regulations and environment improvement plans, etc are the main cause of water pollution, CPHEEO (1999). The pollutants from industrial and domestic discharge find their way to surface water reservoirs and rivers and are also percolating into ground to pollute ground water sources. The polluted water may have unacceptable physiochemical and biological content like colour, odour, taste, turbidity, organic matter contents, harmful chemical contents, toxic and heavy metals, pesticides, oily matters, industrial waste products, radioactivity, high Total Dissolved Solids (TDS), acids, alkalies, domestic sewage content, virus, bacteria, protozoa etc. The organic matter may be biodegradable or non-biodegradable. Pollution of surface waters (rivers, lakes, ponds), ground waters, sea water is all harmful for biodiversity.