The objective of this study is to verify the overall performance and evaluate the wastewater quality of the wastewater treatment plant at the Abu Ghraib Dairy Factory and compare the results with the Iraqi Quality Standards (IQS) for effluent disposal and with the national determinants of treated water use. Agricultural irrigation wastewater, which included daily assessment records of the main parameters affecting wastewater [five-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total dissolved solids (T.D.S), total suspended solids (TSS), phosphate (PO4), nitrate (NO3), hydrogen ion concentration (pH)] obtained from the quality control department of Abu Ghraib dairy plant registered from January 2017 to December 2020. The results of the studied treatment plant showed that the removal efficiency of the influencing parameters is BOD5, COD, TDS, SS, PO4, NO3 were 95.25, 96.61, 71.54, 32.50, and 4.43%, respectively, based on the results obtained from the daily records of laboratory examinations of the plant. These results indicate that the quality of treated wastewater was not following the Iraqi Quality Standards (IQS) for liquid waste disposal due to the failure to achieve the required treatment for phosphate. It is not allowed to use in agricultural irrigation due to the inability to achieve the necessary treatment for the total suspended solids. According to the national determinants of reusing treated wastewater for irrigation, the performance of the treated plant was not efficient enough to achieve the required wastewater treatment.
