A Study On Integrated Control Technology For Renovation Of Combined Sewer System

Urban sewer system is combined sewer system (CSS) nowadays in many bigcities. It faces the challenge of mitigating combined sewer overflows (CSO) and urbanflooding. The model of CSS was built by InfoWorks CS integrated with ArcGIS(Geographic Information System) platform and RS (Remote sensing) technology. TheCSS of study case were diagnosted and analyzed to identify the existing problems andcauses. Meanwhile, an integrated control strategy on the renovation and managementof CSS was proposed. The main contents are as follows:(1) According to the runoff measured results and relevant research parameters, adrainage system model was established.(2) Through the CSS simulation, the existing problems were analyzed and theircauses were found out. Mitigating urban waterlogging and CSO were decided as thefocus of renovation project.(3) An integrated control strategy on the renovation and management of CSS wasproposed. It includes in eight measures, namely the source green control, node storagetanks, sewer network optimization, pump station scheduling, intersystem interceptorsewer, CSO tank, CSO storage tunnel and enhanced primary treatment of wastewatertreatment plant (WWTP).(4) All control strategies were simulated under a series of design rainfall events.The simulation results revealed that the volume of nodes overflow was reduced andthe overloads of CSO and WWTP discharging pollutants to the environment formertime were abated obviously. The proposed integrated control strategy was turned outto be effective in mitigating urban flooding and surface water pollution.(5)18control solutions were generated using orthogonal design method. Then thecontrol effect of different measures were obtained by extreme difference analysis andthe optimal control solution was chose. The results shown that the source control hada great influence on node overflow reduction. And for the CSO control, the effect ofWWTP enhanced primary treatment was obvious and effect of CSO storage tunneland storage tank were obvious as well.