Seasonal Variation in Physico-chemical Properties of Effluent Generated at a Sewage Treatment Plant in Varanasi and It’s Suitability for Irrigation

Abstract

The current investigation was carried out to ascertain the suitability of the influent and effluent of Varanasi's Bhagwanpur sewage treatment plant for irrigation as well as variations in its physicochemical properties throughout the year 2018. The suitability of the water for irrigation was evaluated by taking water samples from the plant's inlet, aerator, and outlet tanks. Then, these samples were examined for heavy metals as well as parameters like pH, EC, TDS, BOD, COD, and dominant anions and cations.The plant's effluent is suitable for irrigating agricultural fields because parameters like pH, nitrate, phosphate, and other cations are below the permissible limit and will provide the necessary nutrients for crops. However, higher concentrations of some heavy metals were a notable concern that will need close attention and ongoing monitoring in the near future if effluent water is to be used for irrigation. The treatment process significantly lowers the effluent water's COD, sulphates, and other ions to levels that allow for surface water discharge, but it leaves the BOD, nitrate, and phosphate content just above levels which are recommended, making it unsuitable for discharge into the holy Ganges since it will cause eutrophication.