Investigating the Feasibility of Reuse of Effluent from Wastewater Treatment Plant in Borujen City, Iran, for Agricultural and Irrigation Uses

Background: Today, due to the expansion of agricultural activities and the occurrence of successive droughts, the utilization of urban effluents for agricultural purposes is a suitable and economical way. However, the safe and responsible use of these resources is essential. Given that the municipal wastewater treatment effluent of Borujen City, Iran, is used to irrigate potato, alfalfa, and wheat products in the form of flood irrigation, the purpose of this study is to investigate the possibility of reusing the effluent of this wastewater treatment plant for agricultural irrigation. Methods: In this descriptive-analytical study, the physical, chemical, and microbial properties of the effluent of Borujen municipal wastewater treatment plant were measured according to the standard methods for the examination of water and wastewater, for 6 months and then were compared with the standard of Institute of Standards and Industrial Research of Iran and the Food and Agriculture Organization (FAO). Findings: The mean concentrations of five-day biological oxygen demand (BOD5), chemical oxygen demand (COD), and total dissolved solids (TDS) parameters in the effluent were 10.00 ± 1.17, 39.19 ± 4.10, and 513.17 ± 8.70 mg/l, respectively. The average of chemical parameters including Cl-, SO42-, PO43-, NO3-, NO2-, Na, Mg, Ca, HCO3-, CO32-, alkalinity, and the average concentration of heavy metals and effluent alkalinity were within the standard range of Industrial Research of Iran and FAO. The average turbidity in the effluent was 54.27 ± 16.47 nephelometric turbidity unit (NTU). This effluent, in terms of sodium adsorption ratio (SAR), was in excellent water group and in terms of electrical conductivity (EC) was in the acceptable water group. The average concentration of heavy metals was less than the permissible level for these metals. The mean concentrations of total coliform and fecal coliform were higher than the standard set for these parameters. Moreover, no parasite eggs were detected in the effluent. Conclusion: The average chemical parameters of effluent of Borujen wastewater treatment plant were within the standards of effluent use in agriculture. However, the concentration of biological parameters of the effluent was higher than the standard level; and in case of more microbiological purification, it can be used for irrigation of edible agricultural products