A sustainability evaluation framework for WET-PPP projects based on a picture fuzzy similarity-based VIKOR method

This paper aims to construct a sustainability evaluation framework based on the extended VIsekriterijumska optimizacija i KOmpromisno Resenje (VIKOR) method under a picture fuzzy environment. First, a sustainability evaluation index system for water environment treatment public-private-partnership (WET-PPP) projects is constructed from the perspectives of the economy, engineering, environment, management, and society, including five criteria and 20 sub-criteria. The constructed index system considers engineering sustainability and management sustainability, and can thus more comprehensively evaluate the “sustainability” of the project and meet the requirements of the new economic environment. Second, a corresponding method for the sustainability evaluation of WET-PPP projects is proposed based on the picture fuzzy similarity-based VIKOR method. The main advantages of the proposed method include the following: (1) the sustainability evaluation process for WET-PPP projects involves linguistic terms and picture fuzzy numbers (PFNs), which can not only more comprehensively describe the uncertainty of human cognition and decision-making processes in the form of positive, neutral, and negative membership functions, but can also reduce the difficulty for decision-makers (DMs) to provide evaluation information; (2) the proposed evaluation method combines picture fuzzy similarity and the traditional VIKOR method, and can therefore not only obtain compromise solutions but can also ensure the stability and feasibility of the evaluation results. Finally, a case study of WET-PPP projects in China is provided to testify the feasibility and effectiveness of the constructed framework. The results indicate that the proposed framework can improve the accuracy of decision-making and can be applied for handling evaluation problems.