A study on the optimization planning of water pollution control for Majiagou Stream in Harbin was carried out. Four water pollution control options were considered. The option regarded as most feasible, both technically and economically, involved the construction and operation of a wastewater treatment works with a capacity of 150,000 m3/day on the upper reach of the stream. The effluent would be discharged into the upper reach of Majiagou Stream and would be used as a water source for the stream, while an interceptor sewer was to be constructed on the lower reach of the stream to collect wastewaters in the lower reach basin and transport them to a centralized wastewater treatment plant.
An optimization study of the relationship between the sewerage interceptor and the sewage treatment plant on the upper reach was conducted. In this study, a comprehensive water pollution control plan, including the sewerage system, sewage treatment plant, and the use of treated wastewater as a water source for Majiagou Stream, was considered as a systematic problem in which many factors were taken into account. Cost-benefit analysis was carried out for both the sewage treatment plant and the interceptors by means of empirical regression equations and diagrams in which various curves showed the relationships between the important factors.