Characterization of domestic grey water composition of Shivamogga urban municipal corporation, Karnataka, India

A study was conducted at Organic Farming Research Centre, Zonal Agricultural and Horticultural Research Station, UAHS, Shivamogga, from 2018 to 2019 to characterize the composition of municipal domestic grey water of Shivamogga city. Ten grey water samples were collected in plastic can by employing random sampling from each ward out of 35 wards 350 grey water samples were collected from Shivamogga municipal city corporation jurisdiction The pH of the domestic grey water was ranged from neutral to alkaline (6.58-8.91) and electrical conductivity was 0.2 – 2.16 dS m-1 with total dissolved solids are ranged from 68.32-1227.25 mg L-1. BOD and COD values are within the permissible limit and ranged from 6 to 32.4 mg L-1, 0.12 to 444 mg L-1, respectively and BOD/COD (0.13 mg L-1) ratio was well below the 2 mg L-1. Among the cations, sodium (0.3-22.98 meq L-1) and potassium (0-22.49 meq L-1) concentrations range was observed and mean cationic concentration was in the order of Na (11.26 meq L-1) > K (7.30 meq L-1) > Ca (2.24 meq L-1) > Mg (1.58 meq L-1). In anions, bicarbonate (0.6-15.3 meq L-1) and chloride (0.5-11.32 meq L-1) concentration was higher in the grey water and carbonate (0-4.2 meq L-1), phosphate (0.01-10.82 meq L-1) and sulphate (0.02-22.0 meq L-1). Among the nitrogen forms nitrate –N (1.12-427.84 mg L-1) and ammonical –N (1.18-40.32 mg L-1) was observed. The mean concentration of micronutrients in domestic grey water was zinc (0.12 ppm), iron (0.41 ppm), manganese (0.15 ppm) were within the permissible range except copper (0.27 ppm) and boron (1.33 ppm) which was above the permissible range and unsuitable for irrigation purpose. Grey water sodium adsorption ratio (SAR:0.13-19.77meq L-1) and residual sodium carbonate (RSC:0.9-7.7 meq L-1) indicated grey water can be used for irrigation purpose with management. Suspended solids (100-2000 ppm) in grey water were above the permissible limit and very hard in nature due to various dissolved salts. Heavy metals are below detectable limit and pathogen E. coli present in the range of 0-1× 103 CFU ml-1.