STUDY ON THE PERFORMANCE OF WASTEWATER TREATMENT PLANT DESIGNED FOR INDUSTRIAL EFFLUENTS

The present study was conducted to assess the performance of the treatment plant installed on the main effluent drain of Hayatabad Industrial Estate (HIE) for reducing pollution load. The objective of the study was to know about the pollution removal efficiency and suggest changes in the existent treatment plant, if required. For this purpose, samples were taken from the effluent, before and after it went through the treatment plant. It was found that the treatment was not sufficient to remove various physical and chemical parameters including Suspended solids (SS), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and Sulfide (S) in order to comply with Pakistan National Environmental Quality Standards (Pak-NEQS).The collected samples were then treated in the laboratory in order to identify and suggest suitable coagulant. For this purpose three different treatments .i.e. Lime, Alum and Alum+Lime were applied. The optimum doses identified were 25, 35 and 26:13 ml respectively. The settling time was 25, 35 and 20 minutes respectively for lime, alum and alum+lime. The results revealed that the combine treatment (Alum + Lime) effectively removed suspended load up to 90%, along with 82% BOD, and 80% COD respectively. Therefore, it was concluded that the installed small scale treatment plant is not enough in its present form and needs to be upgraded by adding a coagulation step.