Most existing studies analyse the early decision‐making processes of public–private partnership (PPP) projects from the perspective of the government or investors, as such decisions involve lengthy negotiations and are likely to lead to unfair results. Hence, there is a need for fair and reasonable investment decision‐making methods. This study investigates the investment return system of PPP wastewater treatment projects. The net present value of investment income is considered the investment decision indicator of social capital, while value for money (VFM) is the indicator of government decision‐making. Considering both yield and VFM, the system dynamics method and Vensim software are used to establish the investment decision model. A case study validates the proposed model and predicts a reasonable range of unit prices and concession periods for wastewater treatment through government–enterprise cooperation, to improve the transparency and initial decision fairness of PPP sewage treatment projects.

中文翻译：

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基于物有所值的污水处理公私合作项目投资决策模型

现有的大多数研究都从政府或投资者的角度分析了公私合营（PPP）项目的早期决策过程，因为此类决策涉及冗长的谈判，并可能导致不公平的结果。因此，需要一种公平合理的投资决策方法。本研究调查了PPP废水处理项目的投资回报系统。投资收益的净现值被认为是社会资本的投资决策指标，而物有所值（VFM）是政府决策的指标。同时考虑收益率和VFM，使用系统动力学方法和Vensim软件建立投资决策模型。