中文摘要：

污水处理项目采用PPP模式,通常签订具有较高风险的长期合同。而此类项目通常签订具有较高风险的长期合同。因此,合理定价及建立价格动态调整机制,成为提高政企合作效率和稳定合作关系的关键因素。本文基于项目现金流量和社会资本预期收益率确定的N PV模型,提出了价格动态调整的触发机制和方法,并以王小郢污水处理PPP项目为实例进行验证,对应用本模型计算的结果与该项目实际运营情况的误差进行分析。结果表明：N PV模型能够维持合理的社会资本回报率,对风险分担有合理的掌控方法,对价格的动态调整具有指导性意义。

英文摘要：

The sewage treatment project adopts PPP mode, and the project usually with a higher risk of long-term contracts. Therefore, reasonable pricing and the establishment of a dynamic price adjustment mechanism are the key factors to improve the efficiency of government-enterprise cooperation and stability. Based on the NPV model of project cash flow and expected returns of social capital, this paper proposes the triggering mechanism and method of price dynamic adjustment, and the wastewater treatment project of Wang Xiaoying was used as an example to verify the results. The error of the calculation result of this model and the actual operation of the project was analyzed. The results show that the PPP project pricing can main- tain a reasonable returns on social capital and have a rational control over risk sharing, which is of guiding significance for dynamic price adjustment.