| South H Town of Jiangsu Province is a typical industrial agglomeration area.Its high level of industrialization,industrial decentralization and high-speed development promote the process of urbanization,but the water environmental pollution problems are also increasingly prominent.The complex drainage network represented by the sewage pipeline network in industrial agglomeration areas with numerous enterprises and complicated sewage discharge situation is characterized by serious problems such as"high water level"operation,sewage overflow and uncontrollable water quality change in the pipeline network.How to effectively evaluate the overall operation of such sewage network and formulate targeted solutions to outstanding problems is an important research topic.In this paper,the sewage system of H town in the demonstration area is studied,the field investigation,data collection and analysis are fully carried out,and the sewage pipe network model of H town is constructed under the condition of low data quality.After repeated calibration and verification,the credible model is put into practical engineering application.Firstly,the operation of the sewage system of this town is evaluated from multiple angles,and the sewage system of this town is based on it.The prominent problems in the system are solved,and a scientific and reasonable optimization strategy is worked out.The uncontrollable water quality in the pipeline network is preliminarily discussed.The operation of the pump station is optimized,the risk of sewage overflow is reduced,and the smooth transportation of sewage is ensured.Relevant research results provide effective support for the construction of local sewage system,and can even provide reference for the operation and management of other municipal sewage systems.According to the investigation and statistical analysis of the sewage system in H Town,the proportion of industrial wastewater in the sewage treatment system can up to 54.8%,and there are widespread violations of sewage discharge.Due to the long history of sewage pipeline network construction,there are serious problems such as silting up,high operating water level,unreasonable sewage overflow and operation management.At the same time,the water quality and quantity fluctuate greatly,which seriously affects the stable operation of the sewage plant and the stable discharge of tail water.The operation and management mode of the sewage system in this town has been unable to meet the needs of the current construction of drainage facilities.Based on the Infoworks ICM model,the basic data of H town sewage system are investigated,analyzed and summarized to form the database of H town sewage system to build the topological structure of sewage pipeline network model.The model checking tool is used to check and reconsider the wrong data in the process of model construction,so as to make the topological structure of the model more accurate.Through on-the-spot investigation and inquiry of relevant data and relevant literature of the town,the relevant parameters of the model are determined.The basic data provided by relevant departments are used to set up the flow process line and delimit the population of the catchment area.The model is calibrated and checked by using the measured daily cumulative flow data of Yunnan Pump Station and Zhenbei Pump Station and the average value of the influent water quality index of the sewage plant,and a credible sewage pipeline network hydraulics model and water quality model is constructed.The current situation of sewage system in H town is evaluated by using the checked sewage pipe network model.The current capacity of the sewage network is analyzed from three aspects:the overload state of the pipeline,the flow rate and the operation state of the pump station.About 90%of the pipelines in Yunnan area and 40%in Yunbei area are in full load or even overload operation,and the current operation state is poor.Simulations and comparisons of different sediment depths show that siltation seriously affects the water diversion capacity and storage capacity of the pipeline network.Scenario analysis method is used to analyze the impact of many enterprises and more sewage point sources on sewage quality in H town,and the impact of illegal sewage discharge is explored.The results show that the discharge of industrial wastewater significantly increases the concentration of pollutants in sewage and makes the distribution of pollutant concentration in the pipeline network uneven;Zhenbei Pump Station should cope with the energy of illegal sewage discharge.Strong force,followed by Yunnan Pump Station,North C Pump Station is the weakest,and the impact of illegal sewage discharge on downstream water quality is different in different areas and different periods.In view of the above prominent problems,through the model simulation study,the safe sewage diversion strategy suitable for H town is put forward,and the optimal drainage volume of the pump station is screened.It is suggested that Yunnan Pump Station should work with 400 m~3/h displacement,and the optimal operating water level of the pump station should be determined by combining the dynamic storage volume of the upstream pipeline and the maximum flow rate of the inlet pipe of the pump station:Yunnan Pump Station should be used-2.4m and Zhenbei-1.3m for pumps opening level.The open water level of the station can effectively improve the dynamic storage capacity of the pipeline and make the inflow of the sewage plant more stable.The above measures optimize the operation of the pump station,reduce the risk of sewage overflow and ensure the smooth diversion of sewage.In order to effectively reduce the impact of illegal sewage discharge on the water quality of the plant,the water quality control of the pipeline network is studied by setting up a storage tank.It is found that the near-end storage tank had better effect on reducing the downstream peak value,and the volume of the storage tank needs to be set up according to the actual sewage discharge situation in the area. |
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