Practice And Discussion On Intercepting Combined Drainage System

Transformation of intercepting combined drainage system has been served as a common way to improve the rain and sewage system at home and abroad. It has been widely adopted for improving the sewage system in old city region, due to its many advantages such as easy operability, economic efficiency, instant reward, construction convenience and low impact on residents around. However, this kind of transformation method also suffers from several shortcomings. For example, it will result in severe dilution of sewage, overly high watercourse and difficulty for long distances, and difficulty in control the closure. These problems bring difficult for design and management of projects, which should be carefully studied by city constructor.Considering the problems of intercepting combined drainage system mentioned above, we first introduce and analysis the commonly used techniques at home and abroad, then describe the practical solutions in Chapter5. Based on a project at Luqiao District in the city of Taizhou, we propose actual measurements of sewage water, and select different interception multiplier in different regions. The problem of sewage water dilution can be solved by separating the main interception pipe and the sewage pipe, and improving the design of interception well. Especially, we propose to solve the problem of river water reverse irrigation by setting a duckbill valve, and control the interception flow by reducing the pipe diameter and setting a rotational flow valve, which yields encouraging results in practical problems. Finally, we give several suggestions for better transforming the interceptive combined drainage system in practice, which can be a good reference for similar closure projects in the future.