Prioritizing potential use of urban treated wastewater using expert-oriented and multi-criteria decision-making approaches: a case study in Iran.

Allocating effluent of wastewater treatment plants to users of economic sectors and satisfying their requirements has created a challenging debate and a need for prioritization. This study assesses the importance of sectors that utilize treated wastewater (TWW) using risk and social acceptability indexes based on expert-oriented approaches. Considered sectors are agriculture, industry, urban green space and natural resources and the study area is located in Iran, around the Isfahan North Wastewater Treatment Plant. The risk index is calculated using Frank and Morgan model and consequently TWW use in the industrial sector is less dangerous than other sectors. Moreover, the social acceptability index, which was determined using Mamdani fuzzy inference set, indicates higher acceptability of TWW use in natural resources sector compared with other sectors. By constructing the conceptual model, generating the decision matrix and using the results of gray relational analysis decision-making model for the four sectors, the allocation priorities of TWW became industry, natural resource, green space, and agriculture respectively. It is suggested that Water and Wastewater Company grant permission for TWW use to water-consuming industries and man-made forests development, which result in increasing employment, reduction of harmful effects of dust, and water consumption decrease.