Conservation of Ground Water at Maheshtala Bleaching and Dyeing Cluster, a Populated Area in West Bengal, India by Implementing Ultra filtration and Reverse Osmosis Based Effluent Treatment Plant—A Case Study

Abstract

The present study endeavors to assess the quantity and nature of effluents generated from textile bleaching and dyeing units in Maheshtala cluster, West Bengal, India and to provide a treatment process to conserve groundwater resources. Installation of decentralized common effluent treatment plants (CETP) with advanced membrane based treatment system will save ground water which can be reused. Effluent discharged from medium, small and tiny units of this cluster estimated at 20,000 KLD lifted through pumps from groundwater aquifer. Studies in Kalikapur area under Maheshtala cluster during 2012–2016 showed following mean concentrations of various physico-chemical variables: pH (7.29), BOD (150 mg/l), COD (457 mg/l), TDS (3534 mg/l), TSS (108 mg/l)) and metals such as Cd (0.02 mg/l), Pb (0.20 mg/l), Cr (0.21 mg/l), Fe (1.69 mg/l) and Na (2367 mg/l). These values exceeded the standard permissible limits stipulated by IS: 10500 (2012) and WHO (2003). Due to absence of CETPs in the cluster wastewater laden with toxic trace metals affects the environment and human health, degrades the quantity and quality of both surface and groundwater, contaminates agricultural land, crops, fruits and vegetables, and causes harm to aquatic life forms. Four to five decentralized CETPs are required to install at different locations of the Mahestala region with a capacity of 5000 KLD each, at least one in Kalikapur area, to purify large volume of wastewater (20,000 KLD) and to produce reusable groundwater to an extent of 11,000 KLD (55%) in a populated urban area at Maheshtala near Calcutta, a leading city of India. Further, population and textile bleaching and dyeing industries in last 10 years are increasing. The reuse of wastewater is inevitable as rainfall is decreasing in last 10 years and a result the groundwater recharge is also decreasing as per West Bengal Statistical Handbook 2014.