ASSESSMENT STUDIES ON WASTEWATER POLLUTION BY TEXTILE DYEING AND BLEACHING INDUSTRIES AT KARUR, TAMIL NADU.

Abstract

The effluent samples from 3 different textile dyeing and bleaching industries E(1), E(2) and E(3), were characterized for their pollution potential. The concentration of total dissolved solids (TDS) were found to be 3785, 4500 and 4210 mg/L for the industries1, 2 and 3 respectively. The BOD’s and COD’s were 342.8 and 642.4 mg/L for E(1), 223.2 and 424.6 mg/L for E(2) and 456 and 838.4 mg/L for E(3). The pH of the effluents were 7.36, 7.8 and 7.6 for E(1), E(2) and E(3) respectively. This implies that the effluents were not in acidic region. The nitrate, nitrite and phosphate concentrations were 21, 37 and 30 mg/L, 0.5, 0.8 and 0.8 mg/L and 25, 36 and 20 mg/L fir E(1), E(2) and E(3). The levels of copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), lead (Pb) and chromium (Cr) were higher than the World Health Organization (WHO) standards for effluent discharge. This shows that the textile effluents have severe pollution potentials since the parameters measured have values above the tolerable limits compared to the world health organization (WHO) standards even if the industries promise their treatment. The results also showed that the ratio of COD:BOD were 1.87, 1.90 and 1.84 for E(1), E(2) and E(3) respectively, indicating that the effluents may not be able undergo up to 50 % substrate biodegradation, thus biological processes may not be feasible for the treatment of these effluents. The high values obtained for the parameters assessed, especially those of the concentrations of the solid and of the oxygen demands, call for a pretreatment of the effluent before its discharge into water body. Also, the high conductivity observed shows that sufficient ions are present in the effluents, thus suggesting that the chemical method of coagulation and flocculation may be an ideal treatment method.