Urban Rejected Water Reuse in Agriculture for Irrigation in Major Cities of India: A Synoptic Review

Indiscriminate and rapid urbanization without sufficient infrastructure to manage huge domestic sewage (urban rejected water) generated by urban centers posing serious threats to different ecosystems in many places across the world. On the other hand, the downstream of urban centers facing an acute shortage of water for irrigation. In recent years reuse of urban waste water is being increased in many countries including India irrespective of adverse impacts on other ecosystems. The present study has provided a synoptic review on urban rejected water reuse for irrigation in the major cities of India with a special focus on banks of the Musi river basin in South India where huge wastewater irrigation is being practiced in the world in comparison with global waste water irrigation practices. In all the cases major contaminants namely fecal coliform, nitrates, Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Dissolved Oxygen (DO) are found in water and with increased soil and groundwater salinity on long term use. The review indicated that there a large scope to intensify the irrigation with proper treatment of wastewater. The study also suggested to understand the impacts of rejected water reuse impact on soilwater-food chain and also emphasizes the need for the establishment of sufficient ETPs to minimize the adverse impacts and also to protect hydroagro ecosystems.