Low efficiency of sewage treatment plants due to unskilled operations in India

Centralized sewage treatment plants may not be a sustainable solution for a developing country such as India. Therefore, we conducted for the first time an integrated assessment of the different technologies currently used for sewage treatment in the state of West Bengal, India. Five decentralized sewage treatment plants and one centralized sewage treatment plant located in different parts of Kolkata were evaluated. We compared influent and effluent water quality, energy consumed, capital and operating costs, and treated wastewater reuse potential. F test was used to validate results on the effect of working days and holidays and seasons on treated water quality. Wastewater management strategy was assessed by performance indicators. Our results show that treatment efficiency was lowest in anaerobic plants not because of faulty technology but due to unskilled operation. Therefore, performance improvement of plants is expected if factors such as monitoring, training of staff, regular and scrupulous desludging, reuse aspects, and rational water tariff are implemented earnestly.