Sustainability assessment of urban water environment treatment public-private partnership projects using fuzzy logic

Purpose In recent years, with the increasingly serious urban water environmental pollution, the government has exerted considerable effort to promote the comprehensive improvement of the water environment and conducted numerous urban water environment treatment public-private partnership (PPP) projects (UWETP-PPP). The sustainability assessment of UWETP-PPP has important theoretical and practical significance for the public and private sectors to systematically evaluate the sustainability of projects and promote the sustainable development of projects. Therefore, the purpose of this paper is to advance a method to evaluate the sustainability of UWETP-PPP. Design/methodology/approach The paper adopted fuzzy logic method to evaluate the sustainability of UWETP-PPP. First, this paper constructed the sustainability assessment indicator system of UWETP-PPP. Second, this paper determined the appropriate linguistic scale for assessing the performance ratings and importance weights of UWETP-PPP sustainability indicators and collected experts' evaluations of the project through questionnaires. Then, the linguistic variables were approximated as fuzzy numbers through the concept of fuzzy theory. Finally, the sustainability of the project was determined and the weak sustainability aspects of the project were identified by calculation. Findings The feasibility of this method was verified by a specific case. And, the results of the case study showed that the UWETP-PPP in Xuchang City, China, was sustainable, and the indicators of weak sustainability of the project were identified, namely, internal return ratio (IRR), sustainable cash flow, provision of employment opportunities, energy efficiency, comprehensive use of water resources, use of innovation materials, renewal of project facilities, adoption of advanced engineering technology, use of construction waste and waste recycling and reuse. This paper also proposed corresponding suggestions for further improving the sustainability of the UWETP-PPP in Xuchang City, China. Originality/value This paper makes two contributions: first, the fuzzy logic method is applied to provide new ideas for a sustainability assessment of UWETP-PPP, and the assessment results facilitate ways to monitor and estimate the degree of sustainability. Second, the identified indicators of weak sustainability provide useful references for the public and private sectors regarding implementing appropriate measures to improve the sustainability level of UWETP-PPP.