Performance evaluation of the wastewater treatment plant of Pelareh Dairy Industry, Iran

Pelareh Dairy Industry (PDI) is located in the west of Iran. The aim of the present study was to assess the quality and quantity of PDI wastewater and compare the results with the regulations. PDI has a wastewater treatment plant that consists of sewage collection system, screening system, equalization tank, clarification tank, anaerobic system for pretreatment, activated sludge processing, disinfection, and solids drying beds. In this research, seven quality parameters, including chemical oxygen demand (COD), five-day biochemical oxygen demand (BOD5), nitrate (NO3), total suspended solids (TSS), phosphate (PO4), temperature (Tºc), and pH, were measured as qualitative variables. Thus, 20 samples were collected from influent and effluent zones. Wastewater samples were collected using random grab sampling during peak hours. Based on the results, the average (SD) COD concentration of the raw wastewater in wet season and dry season was 2152.22 (1384.00) and 1813.38 (518.33) mg/l, respectively. The results revealed that the removal efficiency of BOD5, COD, and TSS at the studied plant was 89.22%, 88.79%, and 71.72%, respectively. Based on achieved results, the pollution load of PDI effluent wastewater was determined and presented. Based on the obtained results, the pollution load based on BOD5 variable was 15.71 kg/day. The obtained results indicate that the treatment plant was not efficient enough to be considered as a treatment process for the removal of suspended solids and organic matter.