Cost optimization of sewage pipelines inspection

Sewage pipelines are considered to be the invaluable asset in municipalities. Inspection process plays a vital role in operation and maintenance (O&M) strategies applied by the concerned municipalities. Fault inspection and regular maintenance of sewage pipelines undoubtedly ensure longer service life; however, it could be a costly process in many cases. The objectives of this study are: indicating the significance of sewer pipelines inspection, defining methods of inspection, discussing the economic factors that affect the selection of appropriate methods of sewer pipelines inspection, and optimizing the most suitable method of sewer pipelines inspection in terms of cost effectiveness. A questionnaire survey including a list of factors of inspection of sewer pipelines in Egypt (from previous researches) was used for information collection (this questionnaire targets civil engineers based on their experience). Then, the collected data was analysed using descriptive statistics, to catch on the factors and methods of inspection of sewer pipelines (first examine the survey response using sample size then graph the results of response). Accordingly, the need for cost optimization solutions for such challenges, which is rapidly increasing, with the purpose of prioritizing the maintenance needs and focusing the municipal engineers' efforts has emerged. The solution requires a systematic approach to diagnose the fault in the network along with regular customized inspection for performance evaluation. This research presents an optimization model for inspection of deteriorated sewage pipelines. The optimization is focused on the overall cost of the inspection process by reaching the optimum approach to diagnose and maintain the sewage pipelines. In this research, Genetic Optimization Algorithm (GA) is applied to various methods of inspects with the intention of achieving the possible optimal cost. The methods of inspection were selected in line with the outcome of a questionnaire completed by field experts. The research revealed that the acoustic inspection method with the minimum work force is the most cost-friendly method.