Design Of Sewage Treatment Plant And Pipe Network In Hanshan Economic Development Zone,Hebei Province

There is no sewage treatment facility in economic development zone in Hebei Province,and the domestic and industrial sewage discharged at will pollutes thedownstream surface water and underground water system.On the basis of fullinvestigation and study,evaluation and prediction and necessary survey data,respect the guidance of Handan city master plan and reply according to the feasibility study report.A new sewage treatment plant will be built with a treatment capacity of 13,000m3/d d.Carry out preliminary design of each specialty for the relevant contents of the project.Make the treated sewage effluent meet the class iv main indexes in reference to the environmental quality standard for surface water GB3838-2002,and meet the class iv effluent standard for surface water.the specific effluent quality is as follows:CODcr?30 mg/L,BOD5?6mg/L,SS?10mg/L,TN?5?10?mg/L,NH₃-N?1.5?2.5?mg/L,TP?0.3 mg/L?The pretreatment process of Hanshan Economic Development Zone Wastewater Treatment Plant adopts coarse and fine screen+vortex-type grit chamber,the secondary biochemical process adopts AAO method for treatment,and the advanced treatment unit adopts magnetic flocculation sedimentation tank denitrification deep bed filter.Ultraviolet disinfection pool is used as disinfection unit.Hanshan Economic Development Zone Sewage Treatment Plant has a small treatment scale and little excess sludge.It is planned to concentrate the excess sludge produced by the sewage treatment plant,condition it,filter and dewater it by plate and frame,and then transport it to the domestic garbage harmless treatment plant for treatment.The water content of the dewatered sludge is less than 60%.In AAO aerobic zone,by controlling aeration and controlling dissolved oxygen?less than 0.5mg/L?in the tank,not only the organic matter is completely removed,but more importantly,the simultaneous nitrification and denitrification is realized,and short-cut nitrification and denitrification occupies a considerable proportion.The operation process of system denitrification saves energy consumption,reduces the demand for carbon source,improves the denitrification efficiency,and avoids the adverse effects caused by nitrate nitrogen accumulation.Dissolved oxygen control is a highlight of the optimization process,and it is also the cornerstone of the treatment effect.In order to realize dissolved oxygen control,new air lifting system,high-efficiency aeration system,intelligent control system,etc.are applied to stably control dissolved oxygen in the aeration tank and realize the system environment required by the process.After comparison and selection of schemes,AAO main biochemical process is finally adopted to treat wastewater,which is feasible in technology,simple in design and management,and low in operating cost.There is no secondary sedimentation tank in this process,which reduces the links of treating structures and the number of electrical equipment,so as to save the power consumption of perennial operation.In the selection of sludge treatment process form,the sludge direct concentration and dehydration process is adopted,which eliminates the sludge digestion link,omits the sludge digestion and heating link and the number of electrical equipment,so as to save the power consumption for perennial operation.After the sewage is treated,the water quality can reach the effluent standard of Class IV,and the reclaimed water can be reused.The reclaimed water can be used for agricultural irrigation,greening in parks and road spraying,cleaning of storage and logistics containers,municipal miscellaneous use,landscape water,domestic miscellaneous use,ecological environment and supplementary surface water.