Mountain City Inland Sewage Interceptor Program, Research, And Technical Measures

Sewage interception is an important measure for municipal water environmental quality control. However, influenced by the situation of old city and water condition, Sewage interception is confronted with problems such as narrowness of space, complexity of construction, big technical difficulty and so on. Aiming at the difficulties of implementation of interceptive combined sewer system in urban rivers of old montanic city, key technical issues were studied in this thesis. New technical means such as laying intercepting sewer on riverbed, use of new-style intercepting well and so on were proposed for implementation of intercepting sewage system in old city. Hydraulic calculation was carried out for the sewer system and results show that flow in intercepting sewer should be considered as pressure-driven when the intercepting sewer was put on river bed.Main work and progresses obtained in this study are summarized as follows.(1) Feasibility of laying intercepting sewer on riverbed were studied under the condition that intercepting sewer is difficult to be laid in the crowded city zone. Improvements were made for the intercepting sewage system, structure and construction mode were designed to make the system with good effect and feasibility. The programme has been approved by the corresponding authority and has been putting into practice.(2) Studies on hydraulic characteristics of intercepting sewer and intercepting well were carried out according to the special laying mode of intercepting sewer. Rules were proposed that the intercepting sewer should be designed using pressure-driven flow instead of gravity-driven flow in it, and material and laying mode of pipeline should be adjusted correspondingly. Hydraulic calculations were conducted for the intercepting sewage system. Difference of flow rates and velocities of pipeline under two flow modes was analyzed and measures for flow rate control of intercepted flow were proposed.