عنوان مقاله [English]
Considering the problem of water shortage in Iran specially in arias such as yazd province that is located in the center of the country, wastewater reuse is one of the most important successful methods to overcome the problem of water shortage. In order to supply water for irrigation and to control the environmental pollution in the Shohada-e-Kargar hospital, the wastewater treated and then reused for irrigation of trees and green fields by using the extended aeration activated sludge system. According to this research, the average of wastewater effluent is approximately 250 m3/day. In this study pH and the content of BOD5, COD, TSS, and MPN in raw wastewater was 7.2, 330mg/l, 460mg/l, 280mg/l and 4.1*108/100ml respectively. The same parameters in the effluent were found 7.6, 45mg/l, 75mg/l, 60mg/l and 3.5*104/100ml respectively. The efficiency of this system for removal of BOD5, COD, TSS, MPN was 86.4% , 83.7%, 78.6% , 99.15% respectively. With respect to the water quality standards prepared by Iranian Environmental Protection Organization, the quality of this effluent is considered to be suitable for agriculture except for MPN which is decrease by increasing the detention time during chlorination. The important parameters of water quality shuch as EC, SAR, Na% in the effluent were 420µs/ml, 2.5, 37.5 respectively and the quality of this effluent is classified as acceptable for irrigation.