Research On The Design Of Centralized Sewage Treatment In A Small Town In The Mountainous Area Of Southern Anhui

The mountain area of Southern Anhui is a famous natural and cultural tourism gathering place in China,which is the source of many rivers,such as Xin’an River,Qingyi River,etc.The overall population density in the mountainous area is small,and there are a large number of towns with profound cultural heritage in the mountains.Due to the limitation of terrain conditions,the population is mostly concentrated in small towns.At present,the construction of sewage treatment facilities in small towns in mountainous areas of Southern Anhui lags behind the economically developed areas of Yangtze River Delta,and the overall sewage treatment capacity is relatively weak.In China,there are few researches on the design of centralized wastewater treatment in small towns in southern Anhui mountainous areas,and the relevant standards and specifications for the construction of wastewater treatment system in small towns in mountainous areas are not perfect.Taking a typical comprehensive small town in the mountainous area of Southern Anhui Province as an example,this paper studies and analyzes the characteristics of sewage quantity and quality,and the construction characteristics of sewage collection pipe network and its supporting facilities.Finally,the engineering design of centralized sewage collection and treatment suitable for the small town is determined through comprehensive research.In this study,small towns are located in mountain valleys with poor terrain and geological conditions.Rivers and national roads pass through the town,and the current landform is complex.Due to the limitation of terrain and economic conditions,the construction of sewage collection and treatment facilities in the town is at a low level.The design of the sewage collection system is based on the terrain and other factors,and the town is divided into three sewage zones to collect sewage from each area,and finally concentrated in the sewage treatment plant in the northeast of the town.Six span separate pipe bridge is adopted to cross the river,and the design location is close to the existing river crossing bridge,which does not damage the original tourism landscape environment.Due to the large elevation difference in the West and south areas,the underground integrated sewage lifting pump station is designed for sewage lifting.The pipe material of sewage pipeline is light flexible pipe which can adapt to the construction conditions in mountainous areas and has the characteristics of resisting geological disasters,scouring and leakage.The scale of small towns and towns in this study is small,and the overall sewage volume is small.At present,the town’s industry and trade and tourism industry are developing rapidly,and the proportion of seasonal floating population such as tourism,students and migrant workers is relatively large,and the sewage volume fluctuates with the seasons.The sewage is mainly domestic sewage,and also contains some industrial wastewater,and the overall wastewater quality is complex.According to the characteristics of sewage in this town,the design scale of sewage treatment plant is designed according to the maximum sewage produced by seasonal floating population,and the pretreatment process is equipped with a large regulating tank.Through the analysis of the characteristics of the influent water quality of the sewage plant,the wastewater treatment process has strong impact resistance and adjustable modified A²/O integrated biological treatment process and deep treatment process.The initial design scale is 800 m³,and the long-term design scale is 1500m³.According to the actual investigation and reference to the inflow water quality of the surrounding sewage plant,the designed inflow water quality is BOD₅:150mg/l,COD_cr:300mg/l,SS:200mg/l,NH₃-H:30mg/l,TN:40mg/l,TP:5mg/l.The designed effluent quality meets the discharge requirements of class I a standard in the discharge standard of pollutants from urban sewage treatment plants（GB18918-2002）.The overall design and research has reference significance for the construction of the centralized wastewater treatment project in small towns in mountainous areas.Figure[23]table[24]...