Comparative study on decentralized treatment technologies for sewage and graywater reuse - a review.

Currently, reservoirs, lakes, rivers etc. are being overloaded by the demand for fresh water, due to rapid industrialization and population explosion, and also the effluents from industries and domestic wastewater are continuously polluting these resources. To address this issue, several decentralized wastewater treatment system (DWTS) have been installed all over the globe to reuse and recycle wastewater/graywater for non-potable uses such as fire protection, toilet-flushing, and landscape irrigation. In this review, a comparison between different DWTS was carried out to evaluate their performance, merits and limitations. Hybrid technologies like the electrically enhanced biomass concentrator reactor and integration of physical/ biological methods with bio-electrochemical systems such as microbial fuel cells were found to be the most promising methods for near complete removal of pollutants from wastewater and also the issue of membrane fouling was reduced to a good extent.