A rainwater pipe network pollution tracing method based on topological residual error analysis
By using a topological residual analysis method, the connection relationships and water flow direction of rainwater pipe networks are automatically identified, solving the problems of low efficiency and high cost in existing source tracing technologies, and realizing rapid location and accurate locking of pollution sources.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- ECOLOGICAL ENVIRONMENT MONITORING & SCI RES CENT OF THE HAIHE RIVER BASIN & BEIHAI SEA ECOLOGICAL ENVIRONMENT SUPERVISION & ADMINISTRATION BUREAU OF THE MINISTRY OF ECOLOGY & ENVIRONMENT
- Filing Date
- 2026-04-20
- Publication Date
- 2026-07-24
AI Technical Summary
In existing technologies, tracing illegal sewage discharge in urban stormwater pipe networks is inefficient and costly, and it is difficult to achieve full coverage diagnosis in large and complex pipe networks. Traditional methods rely on manual experience and are inefficient and costly, making it difficult to accurately locate pollution sources.
By employing a topology residual analysis-based method, rainwater pipe network maps are collected, nodes are classified and a topology matrix is constructed, pollutant exceedance multiples and topology residuals are calculated, and pipe network connection relationships and water flow direction are automatically identified to accurately pinpoint abnormal pipe sections and pollution sources.
It has achieved automation and precision in tracing pollution sources in urban stormwater pipe networks, enabling rapid location of pollution sources in large and complex pipe networks, reducing costs and improving tracing efficiency.
Smart Images
Figure CN122453574A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of rainwater pipe network pollution source tracing, and particularly relates to a rainwater pipe network pollution source tracing method based on topological residual analysis. Background Technology
[0002] Due to the age of urban drainage systems, lagging renovations, or poor management, the mixing and misconnection of rainwater and sewage are widespread. This results in a large amount of sewage being directly discharged into rivers, lakes, and other receiving water bodies through rainwater pipe networks during non-rainfall periods, becoming a significant source of pollution affecting water quality. This "drainage during sunny days" not only causes water bodies to become black and smelly and eutrophic, but also severely weakens the emission reduction benefits of sewage treatment plants. Traditional rainwater pipe network inspections mainly rely on manual experience and end-point monitoring, which suffers from low efficiency, difficulty in tracing sources, and insufficient quantitative analysis, making it difficult to accurately identify the responsible party for sewage discharge.
[0003] In existing urban pipeline maintenance practices, traditional inspection methods often face the dilemma of being "fragmented" and "blind". While manual inspections relying on electronic maps and video inspections using pipeline endoscopes can detect local structural or functional problems, they are inefficient and costly in detecting more concealed illegal sewage discharge behaviors, making it difficult to achieve full-coverage diagnosis in large and complex pipeline networks.
[0004] Therefore, there is an urgent need to establish a scientific, systematic, and efficient technical system for tracing the source of illegal sewage discharge in urban stormwater drainage networks. This system should utilize information technology, digitalization, and advanced monitoring methods to achieve rapid location and quantification of pollution sources, providing strong support for refined water environment management. This invention proposes a tracing scheme based on the topological relationship of stormwater drainage networks, aiming to address the pain points and difficulties currently faced in the supervision of sewage discharge from urban stormwater drainage networks. Summary of the Invention
[0005] To address the aforementioned shortcomings in existing technologies, this invention provides a method for tracing the source of pollution in rainwater pipe networks based on topological residual analysis. This method solves the problems of low efficiency and high cost of existing methods, which make it difficult to achieve full coverage diagnosis in large and complex pipe networks.
[0006] To achieve the above-mentioned objectives, the technical solution adopted by this invention is: a method for tracing the source of pollution in rainwater pipe networks based on topological residual analysis, comprising: Collect rainwater pipe network maps of the study area; Based on the stormwater pipe network diagram, the pipe network inspection wells are classified and abstracted into primary nodes, secondary nodes, and tertiary nodes; the primary nodes correspond to the pipe network inspection wells at the end of the stormwater pipe network; the tertiary nodes correspond to the pipe network inspection wells at the upstream end of the stormwater pipe network; and the secondary nodes correspond to the pipe network inspection wells other than the end and upstream ends of the stormwater pipe network. Based on primary, secondary, and tertiary nodes, the topological relationships describing the direction of water flow are determined; Identify the primary nodes for drainage on sunny days and calculate the pollutant exceedance multiples at these nodes. First-level nodes where pollutant exceedances by more than a threshold are identified as target nodes, thus obtaining a set of target nodes; Based on the topological relationship describing the direction of water flow, the abnormal pipe section list is determined by checking each target node in the target node set as a downstream to upstream node; Based on the list of abnormal pipe sections, the areas that drain water into the abnormal pipe sections will be designated as the areas for door-to-door inspection. Door-to-door investigations were conducted on water users in the areas to identify the sources of pollution in the rainwater pipe network.
[0007] Furthermore, the determination of the topological relationship describing the direction of water flow specifically includes: Determine the stormwater pipe network topology matrix:
[0008] in, This is the topology matrix of the rainwater pipe network; It is a set of nodes, including first-level nodes, second-level nodes, and third-level nodes; For a collection of pipes; Based on the stormwater pipe network topology matrix, the topological relationships of water flow direction between nodes are determined:
[0009] in, For nodes determined based on pipeline sets and nodes Adjacency relationship.
[0010] Furthermore, the expression for the pollutant exceedance multiple of the primary node is as follows:
[0011] in, as a first-level node The pollutants exceeded the standard by multiples; as a first-level node The measured concentration of pollutants; This refers to the standard for pollutant emission concentrations.
[0012] Furthermore, the step of investigating upstream nodes from downstream nodes in the target node set to determine the list of abnormal pipe sections specifically involves: For each target node, perform the following operations: The current target node is regarded as the initial node, and anomaly pipe segment investigation is performed. The anomaly pipe segment investigation is specifically as follows: based on the topological relationship describing the water flow direction, the upstream nodes connected to the initial node are determined to obtain a first upstream node set; for each upstream node in the first upstream node set, the topological residual of the abnormal sewage discharge signal of the intermediate pipe segment with the upstream node as the flow inlet is calculated to obtain the topological residual corresponding to each upstream node in the first upstream node set; the intermediate pipe segment between the upstream node and the initial node with the topological residual less than the threshold is marked as an anomaly pipe segment; the upstream node corresponding to the anomaly pipe segment is removed from the first upstream node set; if the first upstream node set is not empty, all the remaining upstream nodes in the first upstream node set are updated to the initial node, and anomaly pipe segment investigation is performed on each initial node. By integrating all abnormal pipe segments from each target node in the target node set during the upstream node investigation process, a list of abnormal pipe segments is obtained.
[0013] Furthermore, the expression for the topological residual is:
[0014] in, To quantify the current upstream node With downstream nodes Topological residuals of abnormal sewage discharge signals in intermediate pipe sections; To connect with the current upstream node The connected downstream node; For the current upstream node Measured pollutant flux; For the current upstream node With downstream nodes Topological relationships; For downstream nodes Measured pollutant flux.
[0015] The beneficial effects of this invention are as follows: This invention introduces graph theory thinking, highly generalizing the urban stormwater drainage network system into a directed graph in a mathematical sense. By digitally encoding the river outlets (first-level nodes), confluence wells (second-level nodes), and terminal wells (third-level nodes), an adjacency matrix that can accurately map the network connection relationships is constructed. This transformation enables computers to automatically and quickly analyze the complex topological logic and water flow vector direction of the network, completely changing the limitations of previous reliance on manual experience-based judgment, and realizing automated identification and path tracing of network connection relationships. In terms of quantitative diagnosis, this invention uses the adjacency matrix to calculate topological residuals. By comparing the measured flux of a node with the theoretical total load input to all adjacent nodes in the upstream network, background interference can be eliminated. Under the background of "dry weather," any residual signal significantly greater than zero becomes a "digital benchmark" for accurately locating illegal access behavior, providing solid technical support for solving the problem of "intertwined pipelines and hidden sources" in cities. Attached Figure Description
[0016] Figure 1 This is a flowchart of the method of the present invention.
[0017] Figure 2 This is a schematic diagram of the rainwater pipe network node coding in an embodiment of the present invention. Detailed Implementation
[0018] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.
[0019] like Figure 1 As shown, in one embodiment of the present invention, a method for tracing the source of pollution in a stormwater pipe network based on topological residual analysis includes: Collect rainwater pipe network maps of the study area; like Figure 2 As shown, the manholes in the rainwater pipe network are classified based on the rainwater pipe network diagram and abstracted into primary nodes, secondary nodes, and tertiary nodes. The primary nodes correspond to the manholes at the end of the rainwater pipe network; the tertiary nodes correspond to the manholes at the upstream end of the rainwater pipe network; and the secondary nodes correspond to the manholes at the end and upstream end of the rainwater pipe network. Based on primary, secondary, and tertiary nodes, the topological relationships describing the direction of water flow are determined; Identify the primary nodes for drainage on sunny days and calculate the pollutant exceedance multiples at these nodes. First-level nodes where pollutant exceedances by more than a threshold are identified as target nodes, thus obtaining a set of target nodes; Based on the topological relationship describing the direction of water flow, the abnormal pipe section list is determined by checking each target node in the target node set as a downstream to upstream node; Based on the list of abnormal pipe sections, the areas that drain water into the abnormal pipe sections will be designated as the areas for door-to-door inspection. Door-to-door investigations were conducted on water users in the areas to identify the sources of pollution in the rainwater pipe network.
[0020] In this embodiment, a map of the rainwater pipe network in the study area was collected, along with basic data such as the construction date, pipe diameter, material, burial depth (or pipe bottom elevation), and slope of the pipe network.
[0021] Pipeline inspection wells shall be classified according to the following rules: The primary node is located at the very end of the stormwater pipe network and is the direct interface between the pipe network system and the receiving water body (river, ditch); Secondary nodes are located in the middle or main line of the pipeline network. They are usually the connection points where branch pipes merge into main pipes, or key turning points where main pipes change direction or diameter. The third-level node is located at the upstream or end of the pipe network, usually at the starting point of the rainwater collection branch pipe or the intersection of smaller pipelines.
[0022] In this embodiment, a non-rainfall period (no rainfall in the first 72 hours to exclude the impact of rainwater runoff) was selected, and a comprehensive inspection of the primary nodes that directly enter the river and ditch in the study area was carried out using the "drone + foot" method to screen out the primary nodes that drain water on sunny days.
[0023] For sewage outlets that are submerged below the water surface, thermal infrared remote sensing technology can be used for investigation.
[0024] The determination of the topological relationship describing the direction of water flow specifically includes: Determine the stormwater pipe network topology matrix:
[0025] in, This is the topology matrix of the rainwater pipe network; It is a set of nodes, including first-level nodes, second-level nodes, and third-level nodes; For a collection of pipes; Based on the stormwater pipe network topology matrix, the topological relationships of water flow direction between nodes are determined:
[0026] in, For nodes determined based on pipeline sets and nodes Adjacency relationship.
[0027] The expression for the pollutant exceedance multiple at the primary node is:
[0028] in, as a first-level node The pollutants exceeded the standard by multiples; as a first-level node The measured concentration of pollutants; This refers to the standard for pollutant emission concentrations.
[0029] In this embodiment, water quality and quantity monitoring are conducted at drainage points identified during patrols on sunny days. Water quality monitoring indicators generally include chemical oxygen demand (COD), ammonia nitrogen, total nitrogen, and total phosphorus. For areas with water-related industrial or mining enterprises or industrial parks, additional monitoring indicators can be added based on industry-specific pollutant characteristics. Water quality standards adopt local discharge standards or the water environment quality standards of receiving water bodies. Water quantity monitoring uses Doppler flow meters to monitor pipeline flow.
[0030] The process of identifying abnormal pipeline segments by checking each target node in the target node set from downstream to upstream nodes is as follows: For each target node, perform the following operations: The current target node is regarded as the initial node, and anomaly pipe segment investigation is performed. The anomaly pipe segment investigation is specifically as follows: based on the topological relationship describing the water flow direction, the upstream nodes connected to the initial node are determined to obtain a first upstream node set; for each upstream node in the first upstream node set, the topological residual of the abnormal sewage discharge signal of the intermediate pipe segment with the upstream node as the flow inlet is calculated to obtain the topological residual corresponding to each upstream node in the first upstream node set; the intermediate pipe segment between the upstream node and the initial node with the topological residual less than the threshold is marked as an anomaly pipe segment; the upstream node corresponding to the anomaly pipe segment is removed from the first upstream node set; if the first upstream node set is not empty, all the remaining upstream nodes in the first upstream node set are updated to the initial node, and anomaly pipe segment investigation is performed on each initial node. By integrating all abnormal pipe segments from each target node in the target node set during the upstream node investigation process, a list of abnormal pipe segments is obtained.
[0031] The expression for the topological residual is:
[0032] in, To quantify the current upstream node With downstream nodes Topological residuals of abnormal sewage discharge signals in intermediate pipe sections; To connect with the current upstream node The connected downstream node; For the current upstream node Measured pollutant flux; For the current upstream node With downstream nodes Topological relationships; For downstream nodes Measured pollutant flux.
[0033] if If the value is close to 0, it indicates that the pollutants only flow through this section of the pipeline, and the actual source of pollution is located in a more upstream area; if If the value is less than the threshold (which is a negative number close to zero), the determination is made at the current node. With nodes There are illegal sewage discharge access points or incorrect connection points in the pipe sections between them.
[0034] By tracing the source of wastewater step by step through water quality monitoring, the system ultimately identifies all water users who may be discharging wastewater through the stormwater drainage network. Doppler flow meters are used to monitor water volume at downstream network nodes of these users for 24 hours. Based on the water quality and volume monitoring data, the pollutant flux discharged through the stormwater drainage network is calculated.
[0035] In the formula, —Daily pollutant discharge flux from the pipeline network, calculated by monitoring, in tons; —The flow rate of the pipeline discharge is obtained through multiple monitoring by the flow meter, in m³ / s; —The concentration of pollutants in the sewage network was obtained through multiple monitoring sessions synchronized with the flow rate, in mg / L.
[0036] Obtain average daily water consumption data from water users (through water meter records or industry-specific quotas), match typical wastewater discharge concentrations based on the water user's industry type, and estimate the daily pollutant discharge volume of the water user. The calculated daily discharge volume... The average water consumption is compared with that of potential upstream water users (such as car washes, restaurants, and residential communities). Simultaneously, the typical wastewater concentration characteristics of different types of water users are considered to aid in the determination; for example, restaurant wastewater often contains significant oil, while domestic wastewater is discharged in large quantities during morning and evening peak water usage periods, thus enabling precise identification of pollution sources.
Claims
1. A method for tracing the source of pollution in stormwater pipe networks based on topological residual analysis, characterized in that, include: Collect rainwater pipe network maps of the study area; Based on the rainwater pipe network diagram, the pipe network inspection wells are classified into first-level nodes, second-level nodes, and third-level nodes; The first-level node corresponds to the manhole at the end of the rainwater pipe network; the third-level node corresponds to the manhole at the upstream end of the rainwater pipe network. The secondary nodes correspond to the pipe network inspection wells, excluding the end and the upstream of the rainwater pipe network; Based on primary, secondary, and tertiary nodes, the topological relationships describing the direction of water flow are determined; Identify the primary nodes for drainage on sunny days and calculate the pollutant exceedance multiples at these nodes. First-level nodes where pollutant exceedances by more than a threshold are identified as target nodes, thus obtaining a set of target nodes; Based on the topological relationship describing the direction of water flow, the abnormal pipe section list is determined by checking each target node in the target node set as a downstream to upstream node; Based on the list of abnormal pipe sections, the areas that drain water into the abnormal pipe sections will be designated as the areas for door-to-door inspection. Door-to-door investigations were conducted on water users in the areas to identify the sources of pollution in the rainwater pipe network.
2. The method for tracing the source of pollution in stormwater pipe networks based on topological residual analysis according to claim 1, characterized in that, The determination of the topological relationship describing the direction of water flow specifically includes: Determine the stormwater pipe network topology matrix: in, This is the topology matrix of the rainwater pipe network; It is a set of nodes, including first-level nodes, second-level nodes, and third-level nodes; For a collection of pipes; Based on the stormwater pipe network topology matrix, the topological relationships of water flow direction between nodes are determined: in, For nodes determined based on pipeline sets and nodes Adjacency relationship.
3. The method for tracing the source of pollution in stormwater pipe networks based on topological residual analysis according to claim 1, characterized in that, The expression for the pollutant exceedance multiple at the primary node is: in, as a first-level node The pollutants exceeded the standard by multiples; as a first-level node The measured concentration of pollutants; This refers to the standard for pollutant emission concentrations.
4. The method for tracing the source of pollution in stormwater pipe networks based on topological residual analysis according to claim 1, characterized in that, The process of identifying abnormal pipeline segments by checking each target node in the target node set from downstream to upstream nodes is as follows: For each target node, perform the following operations: The current target node is regarded as the initial node, and anomaly pipe segment investigation is performed. The anomaly pipe segment investigation is specifically as follows: based on the topological relationship describing the water flow direction, the upstream nodes connected to the initial node are determined to obtain a first upstream node set; for each upstream node in the first upstream node set, the topological residual of the abnormal sewage discharge signal of the intermediate pipe segment with the upstream node as the flow inlet is calculated to obtain the topological residual corresponding to each upstream node in the first upstream node set; the intermediate pipe segment between the upstream node and the initial node with the topological residual less than the threshold is marked as an anomaly pipe segment; the upstream node corresponding to the anomaly pipe segment is removed from the first upstream node set; if the first upstream node set is not empty, all the remaining upstream nodes in the first upstream node set are updated to the initial node, and anomaly pipe segment investigation is performed on each initial node. By integrating all abnormal pipe segments from each target node in the target node set during the upstream node investigation process, a list of abnormal pipe segments is obtained.
5. The method for tracing the source of pollution in stormwater pipe networks based on topological residual analysis according to claim 4, characterized in that, The expression for the topological residual is: in, To quantify the current upstream node With downstream nodes Topological residuals of abnormal sewage discharge signals in intermediate pipe sections; To connect with the current upstream node The connected downstream node; For the current upstream node Measured pollutant flux; For the current upstream node With downstream nodes Topological relationships; For downstream nodes Measured pollutant flux.