Risk assessment model to prioritize sewer pipes inspection in wastewater collection networks

• Published in: Journal of environmental management 2017-04, Vol.190, p.91-101
• Main Authors: Anbari, Mohammad Javad, Tabesh, Massoud, Roozbahani, Abbas
• Format: Article
• Language: English
• Subjects: Bayes Theorem; Bayesian Network; Cities; Databases, Factual; Fuzzy inference system; Inspection priority; Iran; Models, Statistical; Models, Theoretical; Probability; Risk assessment; Risk Assessment - methods; Waste Disposal, Fluid - instrumentation; Waste Disposal, Fluid - methods; Waste Water; Wastewater collection networks
• ISSN: 0301-4797; 1095-8630
• DOI: 10.1016/j.jenvman.2016.12.052

In wastewater systems as one of the most important urban infrastructures, the adverse consequences and effects of unsuitable performance and failure event can sometimes lead to disrupt part of a city functioning. By identifying high failure risk areas, inspections can be implemented based on the system status and thus can significantly increase the sewer network performance. In this study, a new risk assessment model is developed to prioritize sewer pipes inspection using Bayesian Networks (BNs) as a probabilistic approach for computing probability of failure and weighted average method to calculate the consequences of failure values. Finally to consider uncertainties, risk of a sewer pipe is obtained from integration of probability and consequences of failure values using a fuzzy inference system (FIS). As a case study, sewer pipes of a local wastewater collection network in Iran are prioritized to inspect based on their criticality. Results show that majority of sewers (about 62%) has moderate risk, but 12%of sewers are in a critical situation. Regarding the budgetary constraints, the proposed model and resultant risk values are expected to assist wastewater agencies to repair or replace risky sewer pipelines especially in dealing with incomplete and uncertain datasets. •Efficient risk assessment method can increase the sewer network performance.•A new probabilistic risk assessment model was developed using Bayesian Networks.•Both structural and hydraulic failures have been included in the model.•Probability and consequences of failure values was integrated using FIS.•Proposed model can assist wastewater agencies to detect risky sewer pipelines.