Performance Evaluation of Industrial Effluent Treatment Plants

Discharge of poorly treated effluent from Milk based food industries with high levels of pollutants, caused by poor design & operation of treatment systems, creates major environmental problems. Considering the above stated implications an attempt has been made in this work to evaluate one of the Effluent Treatment Plant [ETP] for dairy waste. Samples were collected from six points: Raw effluent, Oil & grease trap, Equalization tank, Aeration tank-1, Aeration tank-2 & Secondary clarifier to evaluate the performance of ETP. Parameters analyzed for evaluation of performance of ETP are COD, 5-day BOD at 20°C, TSS, Total Nitrogen, Phosphorous, Oil & grease, Chloride & Sulphates. Mass balance of COD, TSS & Nitrogen was performed to find the fate of pollutants in ETP. Parameters like SAR, Na, Salinity, RSC, pH and Oil & grease were used to access the suitability of secondary effluent for reuse in irrigation. The COD, 5-day BOD at 20°C & TSS removal efficiency of ETP were 96%, 95% & 94% respectively. The TDS, SAR, RSC, Chloride, Potential salinity of secondary effluent were 966.7 mg/L, 0.06 meq/L, -2.1 meq/L, 209.9 mg/L & 10.7 meq/L respectively, which are acceptable range for irrigation.