Abstract:Old neighborhoods commonly face problems such as combined rainwater and sewage drainage, incomplete pipeline network data, and narrow streets and alleys. Conventional gravity drainage systems often encounter difficulties in construction and low collection efficiency during rainwater and sewage separation renovation. Taking Fengcheng Old Street in Fengxian District, Shanghai as an example, the application of outdoor vacuum drainage technology in the separation renovation of rainwater and sewage in old neighborhoods is studied. The overall system scheme and key technologies such as the determination of sewage volume, the design of vacuum pumping stations, the layout of vacuum collection wells, and the selection of vacuum pipelines are elaborated. The project serves approximately 13,600 residents, the designed wastewater flow is 500 m3/d, seven semi-underground vacuum stations are constructed with 1,108 vacuum collection wells and about 28 km of vacuum pipelines. Operational results show that the proposed scheme effectively overcomes difficulties in household connection renovation and spatial constraints during construction, and features shallow burial depth, small pipe diameter, low disturbance and high coverage, providing a reference for rainwater and sewage separation renovation in old neighborhoods.
