Study On Countermeasures Of Improving Quality And Efficiency Of Sewage Collection System In A Coastal City Of Southern China

In recent years,in the process of water environment management,the problem of a large amount of sewage directly discharged into the river needs to be solved urgently.In response to this problem,the relevant state departments have clearly stated that the sewage treatment should achieve quality and efficiency improvement,that is,comprehensively improve the collection and treatment capacity and level of urban domestic sewage,and realize full coverage of sewage pipe network and full collection and treatment of sewage.The influent and concentrations of urban sewage treatment plants in a certain coastal city in the south are generally low.At the same time,the problem of large amounts of sewage entering the river is particularly prominent.The city issued the “Work Plan for Comprehensively Promoting the Double Concentration of Influent Water Concentration in Sewage Treatment Plants” to achieve quality improvement and efficiency improvement of the sewage collection system by achieving double lifting targets.Sewage collection system is the key to improving quality and efficiency.This paper takes a city in the southern coastal area as an example.Through on-site investigation,literature research and on-site inspection,it analyzes the key issues affecting the “enhancement and efficiency improvement” of wastewater collection system.Technical countermeasures,and strive to provide decision-making reference for the optimization and transformation of urban sewage collection systems.The investigation and analysis of the problems of sewage collection in a city in the south mainly reflected in incomplete sewage collection and the entry of extraneous water into the sewage collection system.The main reasons for incomplete sewage collection include incomplete pipe network coverage,smuggling,rain and sewage mixing,sewage overflow,and pipe network leakage.The main reasons for the entry of extraneous water into the sewage collection system are pipeline defects,over-cutting of the intercepting system,rain and sewage mixing and tidal,which resulting in groundwater infiltration,rainwater inflow,river water and seawater inversion.On the issue of how to improve the sewage collection rate,the focus is on rapid interception,rain and sewage diversion and reduction of sewage overflow.Comparing the three methods of interception,the results show that the interception measures can only be used as a temporary emergency means.To improve the sewage collection rate,it is necessary to carry out rainwater and sewage diversion construction.The rainwater and sewage diversion and drainage system is more suitable for the city,and proposes the idea of urban sewage network and community pipe network construction rainwater and sewage diversion.Reduce sewage overflow from avoiding high water level operation of sewage treatment plants,controlling non-point source pollution and reducing pipe network sediments.On the matter of preventing the extraneous water into the sewage collection system,the interception system adopts the prevention of repeated interception,accurate control of interception,the installation of anti-backflow facilities at the drain,and the control of river water levels to reduce rain,river and seawater;Long-term sustainable countermeasures,gradually replace the sewage interception system,and solve the problem of rain and sewage mixing;optimize the pipe,improve the construction quality and strengthen the pipeline water level inspection and drainage household management to solve the problem of groundwater infiltration.Finally,in the case area of the city,technology integration and application demonstration were carried out.The water load rate of the sewage treatment plant was stabilized at 100%,the water quality COD and ammonia nitrogen concentration were increased,and the water quality improvement goal was achieved.The water quality of the river was also improved.The feasibility and effectiveness of the above measures in a city along the southern coast.