The Theoretical And Applicable Research On Design Of Intercepted Separate Drainage System

The reasonable choice of drainage system has a direct impact on the environmental and economic benefits of the drainage area. The Intercepted Separate Drainage System is proposed to solve the early rain and protect the receiving water body based on the traditional triage system. By using intercepting manhole and rainwater storage tanks, the Intercepted Separate Drainage System closure the mixed sewage rainwater conduit and the rainwater containing higher surface contaminants. The water that closure to the sewer drainage is delivered to the sewage treatment plant, in order to discharge into receiving water bodies after achieve the emission standard of the country or region; The water closured to the rainwater storage tanks must be strengthening disposed by first level, sewaged and storaged.The Intercepted Separate Drainage System fully displays the protection and utilization of water resources.In this paper, the Zone A, Yangluo Wuhan Economic Development Zone along the river system is accomplished as engineering background, the factors that topography, urban sanitation projects and assimilative capacity of the receiving water body of the study area are comprehensively considered. Chicago rainfall line model was used to produce 1 year, 2 years, 3 years and 5 years rainfall process line of the Zone A of Yangluo Wuhan Economic Development Zone along the river system; Green-Ampt and nonlinear reservoir method was separately used to simulate surface runoff and convergence process; exponential erosion mode was used to simulate the process of accumulation and erosion of surface contaminants; dynamic wave model was used to simulate the transmission process of rainwater in the pipe drainage; the first-order decay model was used to simulate the water attenuation; the regional stormwater management model was eventual established.According to the experience gained calculation and the model simulation analysis, the form of intercepting manhole, the closure amount of rainwater, pipe flow and other design of Intercepted Separate Drainage System were studied, and the following results was achieved:(1) The concentration trends of the closure amount of every Intercepting manhole and pollution factors are basically the same in the Intercepted Separate DrainageSystem.(2) When the inflow pipe slope of rainwater storage tank is constant in the Intercepted Separate Drainage System, along with the the inflow pipe diameter of rainwater storage tank increases, the overflow flow of outfall decreases, but the overflow is reduced about 3%. The effect of increasing the diameter to reduce the overflow traffic is not obvious. Comprehensive considering the construction costs, the inflow pipe of rainwater storage tank should choose a smaller diameter while ensuring to meet the closure amount conditions.(3) When the inflow pipe diameter of rainwater storage tank is constant in the Intercepted Separate Drainage System, along with the inflow pipe slope of rainwater storage tank increases, the overflow flow of outfall decreases gradually, but the reduction is not directly proportional to increase amount of slope. When the inflow pipe slope of storage tank increases by a certain percentage, drains overflow flow rate of decrease slows. Comprehensive considering the environmental and economic benefits, choosing a smaller slope of the inflow pipe of storage tank in the case to meet environmental requirements is recommended.(4) Analysing the factors of the total overflow flow, the overflow flow of cumulative pollutant, it comes out that the Intercepted Separate Drainage System is better than the traditional Triage Drainage System.