Investigation of pollution index parameters in the effluent of wastewater treatment plants in industrial towns of Guilan province

Nowadays, the importance of water is known more than before as a life factor and the axis of sustainable development that to protect and manage it, it needs to be controlled using laboratory tests and regular monitoring program. The purpose of this study was to investigate the treatment plant effluent of three large industrial towns in Gilan province and comparing the index parameters with Environmental Protection Organization standards; the measured parameter included pH, TDS, DO, COD and BOD5. The results showed that, some index parameters in the treatment plant effluent in some industrial towns were more than the approved discharge standards to the receiving environments which indicates the necessity of paying attention to regular monitoring and investigation of wastewater treatment systems in industrial towns more than before.