In order to make up for the shortage of public-private partnership (PPP) model, more and more sewage treatment PPP projects have adopted the asset-backed securitization (ABS) model. To ensure success of sewage treatment PPPABS projects, risk evaluation, which has remained scarcity and unscientific, is becoming an urgent problem to be solved. Firstly, this paper identifies critical risk factors by literature analysis and expert interview. The final risk system is established from the perspectives of macrorisks, basic asset risks, transaction structure risks, operational risks, and other risks, which include 17 second risk factors. Then, the overall risk evaluation method is proposed based on combination weight method and Dempster–Shafer (D-S) evidence theory. Next, Beijing capital Co. Ltd. sewage treatment PPPABS project as a case is employed to verify the feasibility and effectiveness of the proposed method. Finally, awareness of existing risks, suggestions from law risk, quality risk, underwriting and issue risk, and credit enhancement are provided for sewage treatment PPPABS projects. All above studies are expected to provide helpful references for evaluating overall risk of sewage treatment PPPABS projects.

Construction of sponge city PPP projects is perceived as a feasible measure for achieving the sustainable urbanization. To ensure the success of sponge city PPP projects, reasonable sharing of risks among participants, which has remained scarce and unscientific, is becoming an urgent problem to be solved. In order to enable the individual participant to accurately grasp the situation of his own risks, specifically for the individual participant, this paper constructs a risk-sharing framework for sponge city PPP projects. Firstly, this paper identifies critical risk factors by the Delphi method. The final risk evaluation index system is established from the perspectives of political risks, economic risks, construction risks, and operational risks, which include 16 secondary risk factors. Then, risk factors’ weights are determined based on a combination weight method (combining the G1 method and the C-OWA operator). Next, in order to share risks reasonably, the first step is to obtain the risk factors that can be borne by one participant and define the risk factors that need to be shared among participants through the method of combining GCA method and TOPSIS method. The second step is to build a model based on the utility theory to determine the proportion of risks shared among participants. Finally, the sponge city PPP project in Qingshan demonstration area of Wuhan city as an example is employed to verify the feasibility and effectiveness of the constructed risk-sharing framework. All the aforementioned studies are expected to provide helpful references for reasonable risk sharing in sponge city PPP projects.