Engineering Design Of The Third Sewage Treatment Plant In Jinzhou City

Jinzhou City, with regional area of10301km2and a population of three million, is located in the west of Liaoning Province, and two main rivers (Nver River and Xiaoling River) flows through the city. Jinzhou City currently has the actual sewage amount of more than30.0×104m3/d, while treatment capacity of the existing sewage treatment plant is just20.0×104m3/d. According to the sewage treatment situation in Jinzhou City, the document "Liaoning Provincial People’s Government implement views on Xiaoling River basin pollution control work" and Jinzhou Urban Master Plan, to build the third sewage treatment plant in Jinzhou City is necessary.The project comprehensively considered Jinzhou Urban Master Plan, urban water supply and drainage systems, and urban sewage amount forecast. And the sewage treatment scale, influent and effluent quality, sewage treatment level, the joint or divided construction and site selection of the proposed second and third sewage treatment plant in Jinzhou City were analyzed respectively. The sewage treatment scale of the proposed third sewage treatment plant in Jinzhou City was designed as5.0×104m3/d, and the reclaimed water would account for4.0×104m3/d. Assuming the influent sewage with350mg/L CODCr,160mg/L BOD5,210mg/L SS,25mg/L NH3-N,40mg/L TN and5mg/L TP, the removal rates would reach up to about85%,93%,95%,80%,62%and90%, respectively. The national A standard level of effluent quality would be achieved.According to influent quality characteristics and effluent quality requirements for receiving water environment quality standards, the sewage treatment plant used modified A2/O secondary biological treatment with nitrogen and phosphorus removal functions and traditional advanced treatment process with coagulation, sedimentation and filtration processes. Moreover,"mechanical concentrate+frame filter" form was applied for sludge treatment, and the treated sludge with below60%moisture content would be sent to the new municipal solid waste landfill in Jinzhou City. In addition, chlorine dioxide and biofilter were used for disinfection and deodorization respectively.The completion of the third sewage treatment plant of Jinzhou City will greatly reduce urban environment pollution, and effectively improve the overall urban environment. Meanwhile, it is conducive to create a favorable investment environment for Jinzhou City, and to promote the sustainable development of urban economy.