Priority Evaluation of Sewerage Rehabilitation by AHP

摘要

Usually the cost of sewerage rehabilitation is large but the budget is limited. Thus, a priority list for sewerage rehabilitation is necessary. This research is to establish an evaluation model to find out the cost-benefit ratio for each sewer sub-system. An evaluation model was established through an analytic hierarchy process (AHP). Initially, a comprehensive list of factors affecting the sewerage rehabilitation was established based on the result of a brainstorm meeting. Then, through an expert questionnaire, the weights for all affecting factors were estimated. Moreover, appropriate scoring rules, which convert qualitative factors into quantitative score, were set according to literatures, law and regulations, or personal experiences. By multiplying the all quantitative affecting factors and their weights, an overall score can be obtained for the cost-benefit evaluation. Finally, the authorities can set up the strategy for the sewerage rehabilitation by considering both the rehabilitation priority and budget limitation. This evaluation process was applied to a sewerage system in the 9th re-planning district which was located in east Taichung city, Taiwan.