Prioritization of maintenance work in wastewater networks using decision support methods

Abstract

Abstract Sanitation networks are extremely important infrastructures because of their function and capital-intensive nature. Indeed, network knowledge is essential for a reliable prioritization of maintenance work. In this context, this research work is interested in the evaluation and the prioritization of the defects of an Urban Sanitation Network (USN), taking into account the criteria of the FMECA method (failure mode and effects and criticality analysis), namely the probability of defect occurrence (P), the defect's detectability (D) and the defect impact (I). The methodology adopted is based on the combination of three methods: the analytic hierarchy process (AHP) used to assign weights to FMECA criteria, the weighted product model (WPM) method to determine the defect impact and the technique for order of preference by similarity to ideal solution method (TOPSIS) to classify sanitation defects in descending order in order to prioritize maintenance interventions. A case study of a real sewerage project in the city of Bejaia (Algeria) essentially composed of eight non-visitable sections evaluated from television inspections was used to illustrate and validate the proposed model. The results show that the following defects: collapse, chemical attack, pipe surface degradation, and abrasion are considered as critical defects requiring immediate intervention due to their significant influence on the section performance rate, which is between 0%≤P<50%, contrary to the other studied parameters which present a performance rate of P>50%. These results prove that the combination of AHP–WPM–TOPSIS methods can be used to design an effective management and maintenance system.