Performance assessment of cetps post zero liquid discharge implementation in tiruppur, tamilnadu

Modern industrialisation has resulted in wide spread use of water for the industrial chemical processes and thus resulting not only in depletion of natural resources but also the large scale environmental pollution by the discharge of the untreated or partially treated waste water to land and water bodies. The present study covers the waste water pollution resulted by several CETPs located in an around Tiruppur area which discharges to the river Noyyal. Over a period of years with the increase in the production, quantity of waste water getting generated and discharged got increased which eventually depletes both the Noyyal river as well as the surrounding ground water quality. Some of the chemicals such as Sodium chloride used in textile bleaching process without proper treatment and recovery reaches to the water bodies and land resulting in high level of Total dissolved solids in the entire area. This ultimately affect the availability of good drinking water and resulting in dependency of tanker water for drinking water which is brought from places which are around 30 km away from Tiruppur city. In late nineties, the industrial units in Tirupur area have started putting up effluent treatment plants, either individually or collectively depending on their convenience and location in order to prevent water pollution as well as to revive and restore the health of the already damaged environment. Apart from the individual ETPs, 7 CETPs with physicochemical treatment facilities were commissioned during 1998-99 to treat about 40450 KLD of effluent and let-out the treated effluent into drainage canals which join Noyyal river. Due to inadequate treatment facilities, these CETPs as well as the individual ones failed to meet the quality criteria especially the total dissolved solids level of less than 2100 mg/l prescribed for treated effluent (Central Pollution Control Board Standard, 2000). Hence, they were directed to incorporate Zero Liquid Discharge (ZLD) system during the year 31st July 2007 so as to ensure recovery & reuse of water and salt as well as minimize sludge generation.