Research on the risk evaluation of urban wastewater treatment projects based on an improved fuzzy cognitive map

To address the issues of ambiguous uncertainty and conflicting evidence in risk evaluation of wastewater treatment public-private partnership (PPP) project, a risk evaluation approach based on an evidence-based reasoning (ER)-improved fuzzy cognitive map (FCM) and 15 secondary evaluation indexes system are pro-posed. Then, ER is used to fuse expert opinions to obtain a correlation matrix. Finally, the rank evaluation results are obtained by FCM inference. External environmental risk (S), investment and financing risk (F) are the risk factors that have the greatest impact and sensitiveness on PPP wastewater treatment projects. For predictive analysis, the maximum project risk value was 0.5523 when the S value was set to 1, followed by the project risk value when the F value was set to 1. For diagnostic analysis, the greatest change in S value converged to 0.4978 when all risk factors were set to a neutral value of 0.5, while the greatest change in project risk was observed when all risk factors were set to 1. In addition, policy and legal risk, economic risk and market risk are the most sensitive risk factors among all secondary risk factors. The results are able to provide reliable project risk assessment solutions for project decision makers.