The necessity of utilizing unconventional water resources and wastewater has emerged today as an unavoidable imperative, particularly in Iran. The limitations of water resources have directed researchers’ attention toward the rational use of unconventional waters, such as wastewater. The overall aim of the present study is the optimal utilization of wastewater in the cultivation of non-fruit-bearing trees, industry, and eco-park applications, leveraging sustainable development indicators. In the present study, to achieve the objectives and prioritize the use of wastewater (in tree cultivation, eco-park development, or industrial applications), the fuzzy Shannon entropy method was employed to determine the importance of evaluation criteria, and the Fuzzy Additive Ratio Assessment (ARAS) method was used for assessing and prioritizing the options. Given the presence of uncertainty in experts’ opinions, fuzzy concepts and theory were utilized to reflect this uncertainty in the process of evaluating the options. An integrated fuzzy Shannon Entropy–ARAS framework is proposed to evaluate and prioritize wastewater reuse alternatives under sustainability criteria. In order to identify the evaluation criteria, relevant literature and previous studies were reviewed, and a questionnaire was designed and distributed among experts. To identify and prioritize the influential criteria, the snowball sampling technique was employed. During the implementation of this technique, 10 out of the initial 20 criteria were excluded, and ultimately, 10 key and impactful criteria were selected. The results of implementing the fuzzy Shannon entropy and fuzzy ARAS methods revealed that the optimal use of treated wastewater in the Shahrkord plain should initially focus on non-fruit-bearing trees. The second priority for utilizing treated wastewater in the Shahrkord plain is for the construction of eco-parks, while the third priority is its use in industry.
Dehkordi et al. (2026) studied this question.