Study On Diagnosis And Traceability Of Inflow And Infiltration Of Drainage Network In Wangjiangou District Of Hefei City

With the rapid development of the construction of drainage network,urban drainage network becomes increasingly complex,plus its own project concealment,various forms and other factors,leading to a large number of structural and functional problems in urban drainage network.In view of the common inflow infiltration problem in the drainage pipe network,the CCTV detection method can be used to visually detect the internal situation of the pipe network,but there are some problems such as difficult to accurately locate the problematic pipe segment,large detection range and engineering amount,and long time.In this study,a large amount of water quality and quantity data and receptor model were used to study the infiltration problem of intra-regional inflow and conduct traceability analysis,providing a beneficial supplement for CCTV detection method.Taking the municipal drainage pipe network system of Wangjiangou District of Hefei City as the research object,firstly,based on the topological relationship of drainage pipe network in the study area,the layout method of monitoring points of sewage pipe network and rainwater pipe network was studied,so as to divide the study area reasonably according to the location of monitoring points.Then the identification and correction methods of different types of abnormal data in monitoring data are studied.On the basis of the monitored water and quality data,different receptor models were used to make qualitative and quantitative diagnosis of the infiltration problem of the basic sewage network,and the source analysis of the outflow at the end of the rainwater network was carried out.Finally,combined with the actual situation of the pipe network,different evaluation indexes were used to evaluate the inflow infiltration problems in each sub-area of the drainage pipe network,and the regions with serious inflow infiltration problems were analyzed.(1)In the diagnostic study of sewage network inflow infiltration,it is found that in the dry season,the total raw sewage volume in the study area is about 50,800 m3/d,and the total groundwater infiltration volume is about 15,100 m3/d,which is in a moderate degree of severity compared with the infiltration rate of other domestic cities in the dry season.In a rainfall event,the total raw sewage volume in the study area was about 47,700 m3/d,the total rainfall inflow infiltration was 53,300 m3/d,of which the rainfall infiltration was 17,800m3/d,and the rainwater inflow discharge was 35,400 m3/d.The comparison of raw sewage quantity in dry season infiltration and rainfall infiltration shows that the quantitative analysis results of sewage network infiltration based on Monte Carlo theory chemical mass balance model are reasonable and reliable,and can be used to judge pipeline damage and maintenance.(2)In the study on the infiltration diagnosis of sewage network inflow,it is found that in the dry season,domestic sewage and groundwater are the main sources of dry season discharge at the monitoring outlet 18# and 19#,industrial wastewater is the main source of dry season discharge at the monitoring outlet 21#,and groundwater is the main source of dry season discharge at the monitoring outlet 26#.In the case of a certain rainfall,the areas with the most serious sewage inflow in the rainwater pipe network are sub-regions A15 and A16,and the areas with the most serious groundwater infiltration are sub-regions A15,A16 and A18.(3)Different evaluation indexes are used to evaluate the inflow infiltration problem of the sewage network.The conclusion is that the inflow infiltration problem of the three subareas of the sewage network,A2,A5 and A9,is the most serious and should be solved by engineering measures first.Combined with the actual land use type in the study area and the analysis results of traceability,the rainwater pipe network was evaluated and the conclusion was drawn that the inflow infiltration problem in the four sub-areas of A15,A16,A18 and A23 was the most serious and should be solved by engineering measures first.The pipeline detection and repair aimed at the above sub-areas can significantly reduce the inflow infiltration of the whole drainage system,reflecting the advantages of this study,that is,before CCTV detection,the sub-areas with serious inflow infiltration problems of the drainage pipe network system are locked in advance,and then the pipeline detection and repair are focused on the sub-areas.Figure [30] Table [30] Reference [94]...