Evaluation of Effluent Quality of Ekbatan Wastewater Treatment Plant for Agricultural Irrigation with CWQI Model

The aim of the study was to evaluate effluent quality of Ekbatan wastewater treatment plant for agricultural irrigation with CWQI model.
This study was a descriptive- analytical one and lasted for 48 months. In order to determine suitability of effluent quality for being reused in the agricultural irrigation, a total of 22 physicochemical parameters and 3 microbial parameters were measured during four seasons based on one weekly sample (a total of 54 samples). The results were entered into CWQI Calculator software to evaluate the effluent quality for agricultural irrigation.
CWQI value for agricultural irrigation is 56, it means water quality is frequently threatened (conditions often depart from natural or desirable levels). The results also showed that CWQI values for other usage such as drinking, aquaculture and livestock feeding are 30, 38 and 53, respectively and the best possible usage is for livestock feeding.
The results showed that the effluent quality was appropriate for irrigation but was in boundary region. Turbidity and Mercury are the most important factors of low CWQI value. According to the study, the effluent can be used for agricultural irrigation and high quality drinking water usage will be avoided.