Comparing quality of the wastewater treatment plant effluent in Lia industrial zone (Qazvin) with Iranian environmental protection standards (2015)

Background: In order to prevent water pollution, protect public health, and reuse of the treated wastewater; controlling on quality of the wastewater treatment plant effluent has been considered a necessary. Objective: To compare the quality of wastewater treatment plant effluent in Lia industrial zone with Iranian environmental protection standards. Methods: This cross-sectional study was performed in one of the industrial zones in Qazvin (Lia). Samples were collected from wastewater treatment plant from May to September 2015 and analyzed in the laboratory. Chemical oxygen demand (COD) parameters were determined twice per week when the pH values were daily measured by pH meter. Sampling was carried out weekly to determine other important operational parameters including biochemical oxygen demand (BOD), total suspended solids (TSS), total coliform (TC) and fecal coliform (FC). Sampling and experiments were done according to the latest standard methods. The data were analyzed with SPSS 16 software (T-Test a single group). Findings: The average of BOD, COD, TSS, FC, TC in effluent were achieved to 73.3±13.2, 156.2±42, and 76.43±50.8 mg/L 1.1×103,1.1×103 MPN/100 ml respectively. The total average of removal efficiencies for BOD, COD and TSS were calculated 92.41%, 92.75%, and 87.46%, respectively. Conclusion: The results obtained that the wastewater treatment plant systems can be used as an efficient system for reduction of common pollutants by providing the Iranian standards for irrigating when the most important such as BOD, COD, TSS and PH are considered. The quality of the treated wastewater was found to be within the permissible Iranian standards for irrigating. However, it is important to keep in mind that reduce microbial contamination within standards is needed to be considered.