Sewerage rehabilitation planning

Following the construction completion of the new infrastructures of sewerage, sewerage rehabilitation planning is the major work. This paper presents a systematic sewerage rehabilitation planning consisting of sewer inspection, diagnosis of pipe defects, grading of sewerage structural conditions, and determination of cost-effectiveness rehabilitation methods and substitution pipe materials. The main purpose of sewer inspection is to acquire closed circuit TV (CCTV) images for diagnosis of pipe defects. For diagnosis of pipe defects, a computer aided approach rather than the tradition manual interpretation is presented, and the overall diagnosis accuracies of above 90% are obtained. Also, genetic algorithm (GA) is used to design an optimization model to find out the multi-optimal sewer rehabilitation approaches. Finally, a set of optimal sewerage rehabilitation plans is searched.