development of a risk-based algorithm for selection of the best wastewater reuse alternative

wastewater reuse is an essential issue in water resources management. wastewater reuse alternatives application results in hazards that should be investigated for alternatives' risk analysis. the purpose of this study is to develop an algorithm for risk analysis of wastewater reuse alternatives. therefore, by integrating experts’ comments, risk evaluation and assessment model is developed, and alternatives are evaluated from three aspects of environment, health-society and economic risks. in this model, risk is a combination of likelihood, severity of hazard and vulnerability of the system. based on the calculated risks and using fuzzy vikor, wastewater reuse alternatives are prioritized and the best alternative is selected. in this study, shahrak-ekbatan wastewater reuse system is evaluated with three alternatives of “irrigation of green space in treatment plant”, “irrigation of green space in shahrak-ekbatan” and “discharging excess reused wastewater to firoozabad stream”. then first alternative is selected as the best alternative. also, the second alternative is selected, because of its acceptable risk. but third alternative is rejected because of its high risk, and that can be replaced with potential alternatives such as “recreational purposes”. developed approach in this study provides better understanding for users. results of this approach are very important in risk management.