Study On Environmental Effects Of Coastal Creek Retention Tank In The Center Urban Area Of Shanghai

Drainage system overflows of non point pollution in cities has been incriminated a major factor that has caused a recent declining trend in the water quality at surface waterways.Through the river training woks in shanghai downtown,we have encount a "bottleneck problem" that the quality of suface waterways is difficult to improve,so it doesn't meet the aim of Green metropolis.Urbanization in Shanghai lead to a dilemma of preventing flood and conrtrolling the CSOs.The thesis was based on the project "Study on the Environmnet Effect of Retention tank with Overflow at chendu pump station in suzhou creek" which was sponsored by shanghai center drainage operating company.The data in this thesis based on collecting historical literature, selecting the data from drainage pump station,and live monitoring data,and combined with qualitative and quantitative change in different rainfall of pump station CSOs along suzhou creek, were used to analyzed the change on CSOs of chendu road pump station and relevant environmental effects.of retention tank.The main research conclusions of this thesis were summarized as follows:(1)In highly urbanized areas,there exist a dilema between flood and CSOs,and building retention basin along suzhou creek pump station is a main measure that reduce pollution load of CSOs in rain and eliminating overflows quantitative in free and decreasing it in rain..(2)The case study of chendu road pump station moniting on the different rainfll and background data was analysised.The results indicated that.â‘ the water quality of chendu road pump station fluctrated according to the time in whole day.â‘¡the volume and intensity of rainfall fluctrated the concentration of pollution.â‘¢the CSOs of chendu pump station with high concentration of pollutant impacted surface water and sewage farm water quality.â‘£the average level of pollution except BOD5 are approaching developed countries' level.(3)It is assumed that four hypothesis about first flush effcet,the result indicate that catching time play an important role in FFE,the hypothesis of delaying 20 min take place notably that 30% volume of water quantity carry 60%volume of pollutant.(4)Estimating the pollution load of CSOs from chendu road pump station and the enviroment effect of retention tank.The result showedâ‘ CSOs of pollution load inchendu road pump station was:CODcr:337.96ton/year;BOD5:62.24ton/year;TN:3.16ton/year;TP:44.59ton/year, TSS:379.56 ton/year;â‘¡cutting down 2894000 ton water quantity that make up 33%volume of CSOs with operating retention tank,â‘¢the more significant in FFE of pollution factor,the more reduction effect in retention tank,reduction ratio from 31.5%to 49.2%.Retention tank of chendu road pump station reduce organic pollutant better than eutrophicatal material.(5)The thesis reposed on the above study and combined actual condition of drainage system in shanghai,put forward the pollution measures of CSOs in terms of their sources,midway,end controlling and reducing through engineering measures and other measures.