Recently, attention has been given to water shortage in Iran; especially in areas such as the province of Yazd, which has arid and semi-arid climate and is located in the central plateaus of Iran. In these situations, re-using sewage is one of the ways we can overcome the problem of water shortage. In order to combat the issue of water shortage and protect the environment, the Yazd combined cycle power plant has applied the effluent of the hygienic sewage treatment system (the active sludge system with extended aeration modification) for irrigation, which is the aim of this study. Studies show that every worker of this power plant uses 85 liter of water and produces 30 liter of hygienic sewage in every work shift. According to experiments that have been carried out on samples of raw sewage, pH, BOD5, COD and TSS were found in 6.9 , 306.45mg/l, 595.85mg/l, 376.35mg/l, respectively. The amounts of the same parameters were 7, 65.80mg/l, 139.1mg/l, 34mg/l in the samples exiting treatment system, which are in accordance with Iran Department of Environment standards and with the irrigation criteria either. The system efficiency in eliminating some parameters is as follows, 76 % COD, 78% BOD5 and 90 % of TSS. The most important effluent parameters in respect to irrigation water standards are SAR, Cl¯ and EC that have been measured in 6.15meq/l, 10meq/l and 1.882 µ mohs/cm, respectively. Based on comparisons between these amounts and the Wilcox diagram, the treated sewage is categorized as medium according to the quality of water used for irrigation. So it has been used to irrigate the green space within the ambit of the Yazd combined cycle power plant.