The aim of this study is to develop a multi-objective decision-making method, named Simultaneous Evaluation of Criteria and Alternatives (SECA) for optimal ranking of wastewater allocation alternatives. This multi-objective decision-making method is for the continuous environment, meaning that experts can choose the best solution among the solutions obtained. The SECA multi-objective non-linear programming method has three objective functions: (i) maximization of the overall performance of alternatives, (ii) minimization of the deviation of criterion weights from reference point based on the within-criteria variation information, and (iii) minimization of the deviation of criterion weights based on the between-criteria variation information as well as two limitations for the weights of criteria. First, 15 criteria from different fields, including economic, socio-cultural, technological, and environmental, and six alternatives were determined for reusing wastewater, including reuse in the industrial sector, for recreational consumption, supplying environmental demand, artificial aquifer recharge, agricultural irrigation, and landscape irrigation. Then, decision-making matrix was constructed and reference points were calculated. By programming the SECA code in Lingo software and considering different β values, different weights for criteria and alternatives were ranked. In the other words, determining the best value for β was the most important step, so different values for β from 0.1 to 10 were examined. Results showed that in the value of β equal to 4, the maximum value of the objective function was obtained as 0.6926. Therefore, it was the best value for β and the weight of the effects on water resources criterion was equal to 0.0957 and was the most important criterion, and the allocation alternative in the environmental sector with a score of 0.8575 was the best wastewater allocation alternative. Followed by the environmental sector alternative, landscape irrigation, industrial sector, artificial aquifer recharge, agricultural irrigation, and recreational consumption were placed. Therefore, water supply for the environmental sector by considering the effect of wastewater on water resources is the best alternative for optimal allocation of wastewater.

本研究的目的是开发一种多目标决策方法，称为标准和替代方案的同时评估 (SECA)，用于对废水分配替代方案进行最佳排序。这种多目标决策方法是针对连续环境的，这意味着专家可以在获得的解决方案中选择最佳解决方案。SECA 多目标非线性规划方法具有三个目标函数：（i）最大化备选方案的整体性能，（ii）基于标准内变化信息，最小化标准权重与参考点的偏差，以及（ iii) 最小化基于标准间变化信息的标准权重偏差以及标准权重的两个限制。首先，来自不同领域的15个标准，包括经济、社会文化、技术和环境，并确定了六种废水再利用的替代方案，包括工业部门再利用、娱乐消费、供应环境需求、人工含水层补给、农业灌溉和景观灌溉。然后构建决策矩阵并计算参考点。通过在 Lingo 软件中编写 SECA 代码并考虑不同的β值、标准和替代方案的不同权重被排序。换句话说，确定β的最佳值是最重要的步骤，因此检查了 0.1 到 10 之间的不同β值。结果表明，在β值等于4时，目标函数的最大值为0.6926。因此，它是β的最佳值对水资源影响的权重为0.0957，是最重要的标准，环境部门中得分为0.8575的分配方案是最佳的废水分配方案。其次是环保部门替代，景观灌溉、工业部门、人工蓄水层补给、农业灌溉和休闲消费被放置。因此，考虑废水对水资源影响的环保部门供水是废水优化配置的最佳选择。