The effects of using treated municipal wastewater on groundwater quality of north of Isfahan

In order to investigate the effect of using treated wastewater in agriculture on the chemical quality of groundwater at the northern region of Isfahan, an area of 6000 hectares was studied during the years 2018 and 2019 by sampling 46 wells. The location of the studied wells was in two areas under long-term irrigation with effluent for at least 10 years and the control area. Chemical parameters of the samples such as electrical conductivity (EC), chemical reaction (pH), anions including bicarbonate, sulfate, chloride, nitrate and cations including calcium, magnesium and sodium were measured. The results showed that the effect of using treated wastewater on groundwater quality of the region, in shallow and deep wells has a different behavior. Due to the long-term use of treated wastewater for irrigation of agricultural lands, none of the chemical parameters of the deep wells were significant in compared to the control area. But, in area with shallow groundwater, the chemical parameters of EC, bicarbonate (HCO3) and chlorine (Cl) were significant at 5% level as compared to the control. Most of the wells in this area are deep and only 8% of the wells are shallow. Therefore, according to the results, the use of treated wastewater for agriculture in this region has a negligible effect on the chemical quality of deep groundwater and therefore is recommended for use in agriculture.