Efficient Grey Water Treatment and Reuse Options for India—A Review

Abstract

Water scarcity is emerging as a major issue in the urban and peri-urban regions of India which is caused by a high population density, low rainfall and high groundwater extraction. Grey water (GW) treatment and reuse within the same house is an easy option to overcome short-range water shortages (>50%) but requires overcoming social barriers. Biological treatment of GW is challenging due to low fermentable C, complex chemicals such as surfactants and xenobiotics and highly variable loads on treatment systems. Commercial GW treatment technologies are nascent and need to overcome techno-economic bottlenecks as well as enable social integration. This paper reviews small GW treatment technologies and experiences and in turn attempts to collate lessons for India. Downscaled versions of several key wastewater technologies such as membrane bioreactor (MBR), rotating biological contactor (RBC) and constructed wetland (CW) have been captured and their problems for adaptation to Indian conditions are brought out. CW and biofilm reactors appear most suitable considering current conditions.