Feasibility of reusing wastewater in irrigation of green space (Study case: city wastewater of Torbat Heydarieh)

The limitations of water resources in Iran have highlighted the need to reuse wastewater and recycle purified water as one of the solutions to obtain new water resources. In order to investigate the effect of wastewater on the quantitative and qualitative characteristics of Banafsheh and Mina plants in the water year of 2022, different percentages of mixing water with urban wastewater (25-50-75 and 100 percent) obtained from Torbat Heydarieh wastewater treatment plant as experimental treatments were compared with city water as the control treatment. It was implemented in the form of a complete randomized block statistical design with five treatments and four replications. During the growing season, the indicators of the number of flower, green area, flower height and dry weight were measured, and at the end of the growing season, the chemical properties of the soil were measured. Data analysis was done using SAS software at a confidence level of 95% and the results were compared using the LSD test. Based on the obtained results, different proportions of water and sewage had a significant effect on the number of flowers and green surface in both Banafsheh and Mina. But the use of these treatments showed a significant effect on the flower height only in the Banafsheh. By replacing 75% of irrigation water with wastewater the green area and the number of flowers increased by 11% and 54% in the Mina and by 22% and 10% in the Banafsheh respectively. Irrigation with wastewater caused an increase in Na, Ca and Mg elements, a decrease in Fe and an increase in soil EC and SAR compared to the control area. It is recommended to investigate the long-term effects of irrigation with wastewater on the concentration of elements, especially heavy metals, in soil and plants in order to achieve more accurate results.