Performance Evaluation of Wastewater Treatment Plant for Milk Based Food Industry

Abstract

Dairy industry is one of the major industries causing water pollution. In India, dairy industry generates about 6-10 L wastewater/L of milk processed depending upon the process employed and product manufactured. Considering the increased milk demand by 2020 A.D., the milk based food industries in India is expected to grow rapidly and have the waste generation and related environmental problems are also assumed increased importance. Poorly treated wastewater with high levels of pollutants caused by poor design, operation or treatment systems creates major environmental problems when discharged to surface water or land. Considering the above stated implications an attempt has been made in the present project to evaluate one of the WWTP for dairy waste. Samples were collected from six points; Raw effluent [P-1], Oil and grease trap [P-2], Equalization tank [P-3], Aeration tank 1 [P-4], Aeration tank 2 [P-5] and Secondary clarifier [P-6] to evaluate the performance of WWTP. Parameters analyzed for evaluation of performance of WWTP are COD, BOD5 at 20° C, TSS, Total Nitrogen, Phosphorous, oil and grease, Chloride and Sulphates. Mass balance of COD, TSS and Nitrogen was performed to find the fate of pollutants in WWTP. 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, BOD5 at 20° C and TSS removal efficiency of WWTP were 96%, 95%and 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 and 10.7 meq/L respectively, which are in acceptable range for irrigation.