Quality assessment of treated effluent of mayapuri CETP for agricultural use

The quality of treated effluent of Mayapuri Common Effluent Treatment Plant (CETP), Delhi was investigated to judge its suitability for agricultural use. Samples of the treated effluent were periodically collected and analyzed for agriculturally significant physico-chemical and biological parameters by standard methods for the examination of water and wastewater of American Public Health Association. Indices like sodium adsorption ratio (SAR), Na %, residual sodium carbonate (RSC), permeability index (PI), and US salinity diagram were utilized for better understanding of quality of effluent for irrigation. Characterisation for agricultural use was done in accordance with the guideline of Food and Agricultural Organization (FAO) and Environmental protection Act, 1986 (EPA, 1986). Results of pH, HCO₃⁻, NO₃⁻, SO₄^2-, RSC, microbes and trace elements (Cd, Cr, Pb, Zn, and Fe) of samples indicated that this water was under good to slight to moderate quality for agricultural use. However the water quality of treated effluent was characterized as very high salinity hazard (C4) to medium sodium hazard (S2) which can be considered unsuitable for irrigation. The treated effluent can irrigate on an average 8 hectare of land per day and can also supply 3.69–6.04 kg N, 0.49–1.05 kg P and 5.1–8.45 kg K per hectare. Conclusively the treated effluent can't be used directly for irrigation however appropriate dilution with good quality water can make it suitable for use.