EFFICIENCY OF WASTEWATER TREATMENT PLANT IN THE PUNJAB TANNERY SECTOR: A CASE STUDY OF DADA TANNERY

Tanning industry of Pakistan contributes significantly towards foreign exchange earnings of the country. Growing concern of international buyers on environmental compliance, during tanning process, has forced this sector to install wastewater treatment plants to address the issue. This study aims to evaluate the performance of wastewater treatment plant (WWTP) of a local tanning industry. Raw wastewater showed high concentration of organic matter and Chromium. Phosphorous concentration was found deficient for satisfactory biological treatment. WWTP showed overall removal efficiency of 88.81, 84.54 and 62.31% for total suspended solids (TSS), five day biochemical oxygen demand (BOD) and chemical oxygen demand (COD), respectively. Whereas, the mean effluent concentrations of TSS, BOD and COD were 216 mg/L, 199 mg/L and 1023 mg/L, respectively. The effluent from WWTP exceeded the National Environmental Quality Standards (NEQS) for TSS, BOD and COD. It was due to the low concentration of Mixed Liquor Suspended Solids (MLSS) in aeration tank and low Phosphorous concentration in wastewater. NEQS limits for BOD and COD could be met by adding Phosphorous and increasing the MLSS in aeration tank