Economic analyses for optimizing the construction of separate sewer in a hybrid sewer system

摘要

Metropolitan Taipei located in north Taiwan uses a hybrid sewer system consistingnof mostly separate sewer for the populated regions, and partly combined sewer for lessnpopulated regions. This study used the concept that Marginal Cost of Control (MCC) equalsnto Marginal Benefits of Control (MBC) to establish the method for studying the optimalnhousehold connection percentage, and the most cost-effective construction of the separatensewer in the hybrid sewer system. Results indicate the improvement of the receiving waternquality in a cost-effective analysis manner. The most cost-effective sanitary sewernconstruction can be reached when the stream Biochemical Oxygen Demand (BOD5) meetsnthe river quality standard, which can be applied in other cities and existing systems.