Low-concentration high-water-level drainage pipe treatment method

Abstract

The application discloses a treatment method for a low-concentration high-water-level drainage pipeline, which is accurate in diagnosing the causes of low concentration and high water level of the sewage pipeline and fast and effective in treatment, and can be applied in a complex and changeable water quality environment.

Description

Technical Field

[0001] This invention relates to a method for treating low-concentration, high-water-level drainage pipelines, belonging to the field of water environment management technology. Background Technology

[0002] Low-concentration, high-level drainage pipes are defined as drainage pipes where the BOD5 (biochemical oxygen demand) concentration of wastewater inside the pipe is below 100 mg / L, but the fill degree is above 75%. BOD5 is an important parameter in water quality monitoring and wastewater treatment, directly reflecting the content of organic matter in water bodies and its impact on the ecological environment. The fill degree of a drainage pipe is the ratio of the volume occupied by water or wastewater in the pipe to the total volume of the pipe. A reasonable fill degree can ensure the smooth operation of the drainage system, prevent wastewater backflow, improve drainage efficiency, and reduce the burden on wastewater treatment plants.

[0003] Due to their complexity and unique operational characteristics, low-concentration, high-water-level drainage pipelines present numerous challenges and limitations to existing drainage treatment technologies. Firstly, traditional low-concentration wastewater treatment methods primarily target pipelines operating at normal water levels, relying mainly on pipeline mapping, detection technologies, and water quality and quantity monitoring to rule out external water intrusion or other factors leading to low concentrations. However, when dealing with low-concentration, high-water-level drainage pipelines, the lack of visibility into the pipeline's internal structure, uneven pollutant distribution, and unstable wastewater flow patterns make traditional detection and monitoring methods insufficiently accurate and effective in identification. Furthermore, traditional high-water-level drainage pipeline treatment methods mainly restore the pipeline's flow capacity through dredging or repair measures, without addressing the presence of low-concentration issues. This can lead to wastewater flow exceeding the pipeline's flow capacity or other flow bottlenecks. Pipeline flow capacity refers to the maximum flow rate a pipeline can allow to pass under certain conditions (such as pressure, flow velocity, and pipe diameter); it determines the pipeline's drainage capacity. Bottlenecks in water flow primarily refer to the obstruction of water flow during drainage, water supply, or water transmission due to limitations in certain aspects of pipelines, channels, hydraulic structures, etc., thus affecting the overall system's operational efficiency and stability. This makes the problem difficult to resolve completely and has limited impact on improving the efficiency of wastewater treatment plants. Furthermore, traditional drainage system management involves multiple professional fields, including investigation, design, construction, and operation and maintenance, with each field responsible for its respective tasks and handing over results sequentially. When encountering low-concentration, high-water-level drainage pipe problems, the internal issues within the pipes are difficult to accurately identify using the technology of a single professional field, thus hindering efficient resolution. Therefore, given the concealed and complex internal environment of low-concentration, high-water-level drainage pipes, there is an urgent need to propose a new, comprehensive, multi-layered management solution that integrates technologies from different professional fields to achieve scientific management. Summary of the Invention

[0004] The present invention aims to provide a method for treating low-concentration, high-water-level drainage pipes. The method can accurately diagnose the causes of low-concentration and high-water-level operation problems in sewage pipes, and at the same time, quickly and effectively treat the problems to achieve water quality standards and stable operation of the drainage system.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a method for treating low-concentration, high-water-level drainage pipes, characterized in that the method includes the following steps:

[0006] Step 1: Collect basic information on drainage pipes and draw a drainage system diagram based on the basic information; based on the drainage system diagram, determine the scope of high-water-level pipes and determine whether the high-water-level pipes meet the conditions for dredging and testing. If they meet the conditions for dredging and testing, proceed to Step 5; if they do not meet the conditions for dredging and testing, proceed to Step 2.

[0007] Step 2: Increase the sewage transfer capacity downstream of the high-water-level pipeline. At the same time, pump sewage to the downstream of the high-water-level pipeline at the end of the high-water-level pipeline or at the bottleneck point of the flow. Observe the changes in water level and concentration in the high-water-level pipeline to determine whether the conditions for dredging and detection are met. If the conditions for dredging and detection are met, proceed to step 5; if the conditions for dredging and detection are not met, proceed to step 3.

[0008] Step 3: At the main-branch connection node of the high-water-level pipeline, temporarily block the branch pipe and observe the changes in water level and concentration in the high-water-level pipeline to determine whether the conditions for dredging and detection are met. If the conditions for dredging and detection are met, proceed to step 7; if the conditions for dredging and detection are not met, proceed to step 4.

[0009] Step 4: For the high-water-level pipeline, simultaneously perform steps 2 and 3, observe the changes in water level and concentration within the high-water-level pipeline, and determine whether the dredging detection conditions are met. If the dredging detection conditions are met, proceed to step 5. If the dredging detection conditions are not met, identify one of the problem points causing the high-water-level pipeline to operate at low concentration and high water level, which is located in the unsealed pipeline in step 3. Add temporary sealing points in the unsealed pipeline, obtain the specific location of the problem point in the unsealed pipeline, update the drainage system diagram, and treat the problem by abolishing the unsealed pipeline and constructing a new pipeline.

[0010] Step 5: Develop a dredging and testing plan, and carry out dredging work in the areas that meet the conditions for dredging and testing.

[0011] The method provided by this invention is applicable to low-concentration, high-water-level drainage pipes that lack dredging and testing capabilities. For drainage pipes with dredging and testing capabilities, traditional methods should be used for treatment. The essence of low-concentration, high-water-level drainage pipe operation is that the water flow load exceeds the pipe's flow capacity. Dredging and testing are used to determine the specific causes of the low-concentration, high-water-level conditions, such as pipe defects or external water intrusion. The method provided by this invention creates conditions for the high-water-level pipe where the pumping capacity exceeds the water flow load within the pipe.

[0012] According to embodiments of the present invention, the present invention can be further optimized, and the optimized technical solution is as follows:

[0013] In one preferred embodiment, determining whether the high-water-level pipeline meets the conditions for dredging and testing specifically includes: determining whether the water level of the high-water-level pipeline can be reduced to below 20% of the diameter of the high-water-level pipeline and the water depth does not exceed 300mm by pumping water down to this level.

[0014] In one preferred embodiment, if the conditions for dredging detection are not available in step 1, the method further includes the following step before proceeding to step 2:

[0015] a. Determine the rainwater and sewage zones and the layout of main and branch pipes according to the drainage system diagram, set up water quality and quantity monitoring points, and monitor the water quality and quantity of the rainwater and sewage zones; based on the water quality and quantity monitoring data, carry out external water source tracing and investigation operations for the high-water-level pipes that do not have the conditions for dredging and testing, and identify external water intrusion points;

[0016] b. Based on the aforementioned basic information, formulate a renovation plan for the external water intrusion point and implement the renovation to reduce the proportion of external water in the high-water-level pipe section;

[0017] Reducing the proportion of external water can alleviate the problem of low concentration and high water level operation, creating favorable conditions for the implementation of step 2.

[0018] In one preferred embodiment, the basic information includes the pipe material, diameter, elevation, and flow direction of the drainage pipe.

[0019] Basic information can be obtained through pipe endoscopy (CCTV) inspection: a closed-circuit television camera system captures video footage of the inside of the pipe to obtain information such as its internal condition, diameter, and material. CCTV technology is one of the most commonly used pipe inspection methods, providing high-resolution image and video data.

[0020] In one preferred embodiment, the method further includes the following steps: Step 6, after completing the dredging, inspect the drainage pipe; measure the drainage pipe after the dredging inspection, obtain the basic information of the drainage pipe, and update the drainage system diagram.

[0021] In one preferred embodiment, the method further includes the following steps: Step 7: Based on the drainage system diagram updated in Step 6, incorporate the problem points that cause low concentration and high water level in the drainage pipe into the renovation design scheme, renovate the problem points on-site, detect and measure the renovated drainage pipe, obtain the final basic information, update the drainage system diagram, and hand over the drainage system diagram and drainage pipe to operation and maintenance.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: The treatment method for low-concentration high-water-level drainage pipes provided by the present invention uses a variety of technical means, including water quality and quantity monitoring, pumping capacity improvement and temporary sealing, to gradually investigate the specific causes of low-concentration high-water-level pipe problems and ensure that the treatment measures are accurate and effective; through a series of measures, it effectively addresses the complex causes of low-concentration high-water-level operating pipe sections, so that the drainage system can operate stably as a whole and can be applied in complex and variable water quality environments. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the process of the low-concentration, high-water-level drainage pipeline treatment method according to an embodiment of the present invention. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0025] Example 1

[0026] This embodiment 1 proposes a comprehensive and systematic treatment method integrating technologies from professional fields such as investigation, design, construction, and operation and maintenance, based on the causes of low-concentration, high-water-level operation. This treatment method is mainly used for low-concentration, high-water-level drainage pipes that lack dredging and testing capabilities. For drainage pipes with dredging and testing capabilities, traditional treatment methods can be referenced [Reference: Lu Wenlin, Qian Duohuai, Huang Haohui, et al. Research on Investigation and Remediation Strategies for External Water Intrusion in Sewage Pipeline in Shuixiang Area of ​​Dongguan City [J]. Water Supply and Drainage, 2023, 49(S01):433-438.]. According to "CJJ181-2012 Technology for Detection and Evaluation of Urban Drainage Pipelines", CCTV inspection of pipelines should meet the following requirements: CCTV inspection should not be carried out with water, and the water level inside the pipeline should be ensured to be no more than 20% of the pipeline diameter and not exceeding 300mm. The steps of the treatment method include:

[0027] Step 1) Pipeline measurement and drainage system diagram drawing

[0028] First, obtain basic information about the drainage pipeline, including pipe material, diameter, elevation, and flow direction. This basic information can be obtained using existing technologies.

[0029] Pipeline endoscopy (CCTV) inspection: This method uses a closed-circuit television camera system to capture video footage of the inside of pipelines, obtaining information such as internal condition, pipe diameter, and pipe material. CCTV technology is one of the most commonly used pipeline inspection methods, providing high-resolution images and video data.

[0030] After completing the basic information collection, the results are analyzed and studied to create a drainage system diagram. This diagram is used to clarify the scope of high-water-level pipe sections and to determine areas where dredging and testing are not feasible, thus providing a basis for subsequent remediation work. Commonly used technical methods include:

[0031] Data integration and processing: Integrate data from different sources such as CCTV, laser scanning, and sonar, and use data processing software (such as AutoCAD, ArcGIS, etc.) to perform data cleaning, format conversion, and spatial analysis.

[0032] Hydraulic model construction: Based on the collected pipeline information, a hydraulic model of the drainage system is constructed to simulate parameters such as flow rate, velocity, and pressure of the pipeline.

[0033] Drainage system diagram drawing: Utilizing CAD or GIS software, a drainage system diagram is drawn, labeling information such as pipe material, diameter, elevation, and flow direction. Drainage system diagrams typically include plan views, sectional views, and 3D models.

[0034] Risk assessment and optimization design: Through hydraulic models and drainage system diagrams, risk assessments can be conducted to identify potential drainage problems (such as water accumulation and overflow) and to propose optimized design solutions.

[0035] The formation of a drainage system diagram: A drainage system diagram is the final result of the collection and analysis of basic information on drainage pipelines, and typically includes the following:

[0036] Plan view: Shows the layout of the drainage pipes, and marks the pipe direction, diameter, material and other information.

[0037] Cross-sectional view: Shows the longitudinal section of the pipeline, marking information such as the pipeline's elevation and slope.

[0038] 3D Model: A 3D model generated based on laser scanning or CCTV data, which intuitively shows the spatial distribution and internal condition of the pipeline.

[0039] Data report: Includes basic pipeline information, inspection results, risk assessment and optimization recommendations.

[0040] Step 2) Source tracing and investigation of external water and monitoring of water quality and quantity

[0041] For areas identified in step 1) that lack the conditions for dredging and testing, further investigation of external water sources will be conducted to identify points of external water intrusion. Based on the drainage system diagram, the zoning of stormwater and sewage, and the layout of main and branch pipes will be clearly defined, and water quality and quantity monitoring points will be established [Reference: Zhou Mei, Li Zheng, Xiong Wen, Min Zhicheng, Huang Yu, Zhang Yi. Application Research of Zoning Monitoring and Diagnostic Method in Urban Drainage Network Investigation [J / OL]. Water Resources and Hydropower Express, 20240420.], and zoning water quality and quantity monitoring will be carried out. The water quality and quantity monitoring data will be used to guide the investigation of external water sources, improve the accuracy of the investigation, and ensure that external water intrusion points are identified as comprehensively as possible in pipe sections operating at low concentrations and high water levels and their upstream branch pipes.

[0042] Step 3) Investigate and rectify the main external water intrusion problems immediately.

[0043] For any external water intrusion points discovered during the investigation, a strategy of immediate rectification is adopted. Based on the basic information of the drainage network, such as pipe material, pipe diameter, elevation, and flow direction obtained in step 1), a renovation plan is prepared, and specific renovation measures are implemented [Reference: Zhou Lei, Shen Xiaohua. Practice of Sewage Pipeline Network Investigation in Main Urban Area of ​​Nanjing City [J]. Water Supply and Drainage, 2022, 48(9):5.]. After the renovation is completed, reducing the proportion of external water in the sewage system can alleviate the problem of low concentration and high water level operation to a certain extent, creating favorable conditions for the implementation of the next step.

[0044] Step 4) Experiment to improve extraction and discharge capabilities

[0045] First, maximize the sewage transfer capacity downstream of the drainage system, for example, by increasing the sewage treatment plant or sewage pumping station to full capacity. Simultaneously, at the end of high-water-level pipe sections or other flow bottlenecks, use mobile pump trucks (sewage pumps) to lift sewage downstream and observe changes in water level and concentration within the drainage pipe to assess whether the pumping effect meets the sludge removal detection conditions: if the sludge removal detection conditions are met, proceed to step 7); if not, proceed to step 5.

[0046] Step 5) Temporary plugging test of branch pipe

[0047] At the junction of the main and branch pipes in the high-water-level section, divers are used for underwater sealing operations to temporarily seal the branch pipes (e.g., using airbags, brickwork, or steel plates). This measure aims to reduce the amount of water flowing into the high-water-level section and to monitor changes in water level and concentration within the drainage pipes; assess whether the dredging and detection conditions are met: if the dredging and detection conditions are met, proceed to step 7); if not, proceed to step 6.

[0048] Step 6) Combined experiment of improving pumping capacity and temporary plugging of branch pipes

[0049] Steps 4) and 5) are carried out simultaneously. In step 4), the pipe section being drained is the same as the unsealed pipe section in step 5). The water level and concentration changes within the drainage pipe are observed to assess whether the dredging detection conditions are met. If the dredging detection conditions are met, proceed to step 7).

[0050] If dredging and testing are not feasible, it can be determined that one of the problem points causing the low concentration and high water level in the drainage pipe is located in an unsealed section of the pipe. In this case, it is only necessary to add temporary sealing points to the unsealed pipe to reduce its length. Ultimately, the specific location of the problem point in the unsealed pipe section can be found and updated in the drainage system diagram. The corresponding solution is to abandon that section of pipe and build a new drainage pipe to replace it. To investigate whether other pipe sections have other factors causing the low concentration and high water level problem in the drainage pipe, it is still necessary to proceed to step 7 for other pipe sections that have dredging and testing capabilities.

[0051] Step 7) Drainage pipe dredging and inspection

[0052] By implementing the aforementioned steps in this embodiment, a dredging and testing plan is developed, and dredging work is carried out on pipe sections that meet the dredging and testing conditions. Testing is carried out immediately after dredging is completed in order to understand the internal quality status of the pipeline and assist in the analysis and research of the causes of high water level and low concentration problems.

[0053] Step 8) Pipeline measurement and updating of drainage system diagram

[0054] After dredging and removing interference factors such as siltation, obstacles, and abnormal pipe diameter in the inspection well, the pipe section after dredging and inspection still needs to be accurately measured. The drainage system diagram is then updated based on the newly acquired basic information such as pipe material, pipe diameter, elevation, and flow direction to ensure the accuracy and reliability of the drawing information.

[0055] Step 9) Problem Point Renovation Construction

[0056] Based on the revised drainage system diagram obtained from the aforementioned steps, the identified problems were analyzed in depth. The issues leading to low concentrations and high water levels in the drainage pipes were incorporated into the renovation design scheme to ensure the design's relevance and feasibility [Reference: Zhou Lei, Shen Xiaohua. Practice of Sewage Pipeline Network Investigation in Main Urban Area of ​​Nanjing City [J]. Water Supply and Drainage, 2022, 48(9):5]. According to the design scheme, the problematic points were renovated on-site, and the renovated drainage pipes were inspected and measured to obtain basic information such as the final pipe material, pipe diameter, elevation, and flow direction. The drainage system diagram was then updated, and finally, the drainage system diagram and drainage pipes were handed over for subsequent operation and maintenance.

[0057] The main cause of the low concentration and high water level problem in sewage pipe networks is essentially that the pipe network is operating under overload conditions. Step 4) is suitable for situations where the degree of overload in the sewage pipe network is not particularly high. In this case, taking step 4) can meet the prerequisite for implementing step 7). Step 5) is suitable for situations where taking step 4) still cannot meet the prerequisite for step 7, such as when a branch pipe is connected to a river and the water level is consistent with the river water level, making it impossible to drain the river water to meet the testing conditions. Therefore, it is necessary to block the branch pipe to isolate the key water load source and achieve a drop in the pipe network water level. After isolating the water in the branch pipe, the water stored in the main pipe will be completely drained downstream over time. However, the key water load source in step 5) is not necessarily from the branch pipe; it may also be a rupture in the main sewage pipe itself, leading to a low concentration and high water level situation in the pipeline. Therefore, it is possible that neither step 4) nor step 5) can meet the testing conditions when implemented individually. Step 6) involves aligning the implementation time of the measures in steps 4) and 5) and then observing whether the implementation requirements of step 7) can be met. If the main pipe rupture is not severe, the dredging and detection conditions in step 7) can be met. If the main pipe rupture is severe, causing its water level to be close to the groundwater level or river level, then there will be an extreme situation where the detection conditions still cannot be met. In this case, by further implementing the temporary sealing measures in step 6), the scope can be further narrowed down, and the location of the problematic pipe section can be finally found.

[0058] Compared with existing technologies, the treatment method for low-concentration, high-water-level drainage pipes provided in Embodiment 1 has the following advantages:

[0059] 1. Comprehensiveness: Combining technical methods from four professional fields—investigation, design, construction, operation and maintenance—to form a comprehensive treatment plan that ensures a thorough solution to the problem of low-concentration, high-water-level drainage pipes from multiple angles and levels;

[0060] 2. Systemic Approach: Through multi-step, multi-stage systemic governance, problems are fully identified and effectively addressed. This not only resolves individual problem areas but also ensures the overall stable operation of the drainage system through a series of measures.

[0061] 3. Precision: Utilize various technical means, such as water quality and quantity monitoring, pumping capacity enhancement experiments, and temporary sealing experiments, to gradually investigate the specific causes of the problem and ensure that the treatment measures are precise and effective;

[0062] 4. Flexibility: Based on different situations and the complexity of the root causes of problems, adopt a step-by-step approach, such as pumping capacity improvement experiments and branch pipe temporary sealing experiments, to flexibly deal with different types of problematic pipe sections;

[0063] 5. High efficiency: The measures of immediate investigation and rectification make the treatment process more efficient, reduce waiting time, quickly deal with external water intrusion problems, and improve treatment efficiency;

[0064] 6. Innovation: By comprehensively applying technologies from the fields of investigation, design, construction, operation and maintenance, a systematic governance method that organically combines time and space is formed, thereby improving the scientific nature and effectiveness of governance;

[0065] 7. Adaptability to complex environments: In view of the special characteristics of low-concentration, high-water-level drainage pipelines, a multi-step, multi-technical system treatment method is proposed, which can be applied in complex and ever-changing water quality environments and effectively solves problems that are difficult to solve by traditional methods.

[0066] 8. Dynamically adjust the treatment plan: During the treatment process, the treatment plan is dynamically adjusted by observing changes in water level and concentration to ensure that each measure is optimized and improved based on the latest test results;

[0067] 9. Economic efficiency: The investigation measures should be implemented gradually based on their workload and cost, prioritizing those with lower workload and cost to ensure that all problems are discovered while avoiding waste of resources during the investigation process.

[0068] In summary, the treatment method for low-concentration, high-water-level drainage pipelines provided in Embodiment 1 can effectively address the complex causes of low-concentration, high-water-level operating pipeline sections.

[0069] Example 2

[0070] A certain city's wastewater treatment plant has a designed capacity of 30,000 m³. 3 / d, after commissioning, the actual influent volume reaches approximately 36,000 m³, which is the maximum treatment capacity of the wastewater treatment plant. 3 The main sewage culvert measures 1.6 × 1.6 m, with an average operating water depth of 4.1 m, resulting in frequent sewage overflows. The monthly average BOD5 concentration of the wastewater treatment plant influent is only 36 mg / L, drawing attention from environmental inspectors. Due to the deep water level in the fully operational pipe section and the large sewage flow, conventional investigation techniques have been used for three consecutive years, but the cause of the low concentration and high water level in the main sewage culvert has remained unexplained. The treatment process according to the method provided in Example 1 is as follows:

[0071] 1) Pipeline surveying and drainage system diagram drawing

[0072] Pipeline surveys were conducted on the aforementioned low-concentration, high-water-level pipe section and surrounding drainage network for approximately 20.1 km to obtain basic information such as pipe material, diameter, elevation, and flow direction, and a drainage system diagram was drawn.

[0073] 2) Source tracing and investigation of external water sources and monitoring of water quality and quantity

[0074] For drainage pipes with dredging and testing capabilities, external water source tracing and water quality and quantity monitoring were carried out. Preliminary identification of 35 points where external water invaded the sewage system was achieved, including 28 groundwater infiltration problems, 4 construction dewatering and drainage misdischarge problems, and 3 river water backflow problems.

[0075] 3) Investigate and rectify major external water intrusion problems immediately.

[0076] A renovation plan was developed for the 35 external water intrusion points, and the renovation was implemented. Non-excavation repair and temporary sealing measures were used to rectify the intrusion, reducing the external water volume by approximately 16,000 m³. 3 / d, at which point the water level in the main sewage culvert drops by an average of about 0.1m.

[0077] 4) Experiment on improving pumping and discharging capabilities

[0078] The document proposes a need to increase drainage capacity, identifies drainage locations, and mandates the deployment of one 18,000 m³ / h drainage unit. 3 / d Mobile pump trucks, combined with temporary sewage pumping stations in the sewage system (44,000 m³) 3 / d) and wastewater treatment plant (30,000 m³) 3 / d) Upgraded to the maximum scale, increasing the total end-of-pipe pumping capacity of the high-water-level pipeline section to 92,000 m³. 3 / d, the water level dropped by 1.0 to 1.5m overall. However, at this time, the conditions for carrying out dredging and testing on pipeline sections operating with low concentrations of water and high water levels are still not met.

[0079] 5) Temporary plugging test of branch pipe

[0080] The locations of temporary branch pipe blockages were analyzed and implemented. Temporary blockages and drainage were carried out at 8 major branch pipe nodes upstream of the main sewage culvert, resulting in an overall water level reduction of approximately 0.8 to 1.0 meters.

[0081] 6) Combined experiment on improving pumping capacity and temporary plugging of branch pipes

[0082] By coordinating measures 4) and 5), the temporary sealing of the branch pipe was combined with measures to enhance pumping capacity, successfully lowering the water level in the main sewage culvert by 2.0–3.0 meters. For the first time, the sewage culvert level dropped below the top slab, preliminarily meeting the conditions for conducting pipeline QV inspection. Pipeline QV inspection, also known as Pipe Quick View Inspection, is a technique that uses a pipe periscope to inspect pipelines inside sewage inspection wells or other fixed spaces. Its advantage lies in its ability to clearly see and record everything inside the pipeline from a distance.

[0083] 7) Drainage pipe dredging and inspection

[0084] Develop a dredging and inspection plan, inspect drainage pipes, carry out dewatering and dredging, maintain and improve pumping capacity and implement temporary branch pipe sealing measures, quickly conduct QV inspection of the pipelines, and use QV inspection videos to identify other sewage systems (500,000 m³). 3 / d) The gate separating the sewage from this sewage system was damaged, resulting in 500,000 m³ of sewage. 3 Wastewater continuously flows into this wastewater system, eventually causing the water levels in both systems to remain the same, resulting in a high-water-level operation problem. After repairing the gate, the water level in the main wastewater culvert decreased to 0.5–2.1 m, but the BOD5 concentration in the wastewater treatment plant influent was still only 40–60 mg / L, and the influent flow to the wastewater treatment plant decreased to 32,000 m³. 3 / d or so.

[0085] Subsequent dredging and inspection of drainage pipes revealed 58 groundwater infiltration defects, 2 water pipe bursts leading to sewage system infiltration, 1 construction site pit dewatering mismanagement issue, and 11 river water backflow issues.

[0086] 8) Pipeline surveying and updating of drainage system diagrams

[0087] Obtain basic data on drainage pipes, compile it into a booklet, incorporate the findings into the drainage network database, and update and improve the drainage system diagram.

[0088] 9) Problem point renovation and construction

[0089] A renovation plan was developed and implemented, employing methods such as trenchless repair, temporary sealing, and excavation and pipe laying to address the aforementioned problems, ultimately reducing the area by approximately 12,000 m². 3 / d external water, the influent volume of the sewage treatment plant has been reduced to 20,000 m³. 3 / d or so.

[0090] Implementation effect

[0091] After the rectification was completed, the annual average BOD5 level of the wastewater treatment plant's influent improved from 36 mg / L to 93 mg / L, and the influent volume of the wastewater treatment plant increased from 36,000 m³. 3 / d reduced to 20,000 m 3 / d, the operating water level of the main sewage culvert stabilized between 0.2m and 1.2m, restoring normal operating conditions. By solving the problem of low concentration and high water level operation in the sewage pipeline, the sewage treatment plant achieved an average annual saving of approximately 20 million yuan in sewage treatment costs, and there have been no further incidents of sewage overflowing onto the ground.

[0092] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present embodiments by those skilled in the art will fall within the scope defined by the appended claims.

Claims

1. A method for treating low-concentration, high-water-level drainage pipes, characterized in that, The method includes the following steps: Step 1: Collect basic information on drainage pipes and draw a drainage system diagram based on the basic information; based on the drainage system diagram, determine the scope of high-water-level pipes and determine whether the high-water-level pipes meet the conditions for dredging and testing. If they meet the conditions for dredging and testing, proceed to Step 5; if they do not meet the conditions for dredging and testing, proceed to Step 2. Step 2: Increase the sewage transfer capacity downstream of the high-water-level pipeline. At the same time, pump sewage to the downstream of the high-water-level pipeline at the end of the high-water-level pipeline or at the bottleneck point of the flow. Observe the changes in water level and concentration in the high-water-level pipeline to determine whether the conditions for dredging and detection are met. If the conditions for dredging and detection are met, proceed to step 5; if the conditions for dredging and detection are not met, proceed to step 3. Step 3: At the main-branch connection node of the high-water-level pipeline, temporarily block the branch pipe and observe the changes in water level and concentration in the high-water-level pipeline to determine whether the conditions for dredging and detection are met. If the conditions for dredging and detection are met, proceed to step 5; if the conditions for dredging and detection are not met, proceed to step 4. Step 4: For the high-water-level pipeline, simultaneously perform steps 2 and 3, observe the changes in water level and concentration within the high-water-level pipeline, and determine whether the dredging detection conditions are met. If the dredging detection conditions are met, proceed to step 5. If the dredging detection conditions are not met, identify one of the problem points causing the high-water-level pipeline to operate at low concentration and high water level, which is located in the unsealed pipeline in step 3. Add temporary sealing points in the unsealed pipeline, obtain the specific location of the problem point in the unsealed pipeline, update the drainage system diagram, and treat the problem by abolishing the unsealed pipeline and constructing a new pipeline. Step 5: Develop a dredging and testing plan, and carry out dredging work in the areas that meet the conditions for dredging and testing.

2. The treatment method for low-concentration, high-water-level drainage pipes according to claim 1, characterized in that, If the conditions for dredging and testing are not available in step 1, the process before proceeding to step 2 includes: a. Determine the rainwater and sewage zones and the layout of main and branch pipes according to the drainage system diagram, set up water quality and quantity monitoring points, and monitor the water quality and quantity of the rainwater and sewage zones; based on the water quality and quantity monitoring data, carry out external water source tracing and investigation operations for the high-water-level pipes that do not have the conditions for dredging and testing, and identify external water intrusion points; b. Based on the aforementioned basic information, formulate a renovation plan for the external water intrusion point and implement the renovation to reduce the proportion of external water in the high-water-level pipeline.

3. The treatment method for low-concentration, high-water-level drainage pipes according to claim 1, characterized in that, Determining whether the high-water-level pipeline meets the conditions for dredging and testing specifically includes: determining whether the water level of the high-water-level pipeline can be reduced to below 20% of the pipe diameter and the water depth does not exceed 300mm by pumping water down to the point where the water depth does not exceed 300mm.

4. The treatment method for low-concentration, high-water-level drainage pipes according to claim 1, characterized in that, The basic information includes the pipe material, diameter, elevation, and flow direction of the drainage pipe.

5. The method for treating low-concentration, high-water-level drainage pipes according to claim 1, characterized in that, The method further includes the following steps: Step 6: After dredging is completed, the drainage pipe is inspected; the drainage pipe is measured after dredging and inspection, the basic information of the drainage pipe is obtained, and the drainage system diagram is updated.

6. The treatment method for low-concentration, high-water-level drainage pipes according to claim 2, characterized in that, The method further includes the following steps: Step 7: Based on the updated drainage system diagram in Step 6, incorporate the problems causing low concentration and high water level in the drainage pipe into the renovation design scheme, carry out on-site renovation of the problem points, inspect and measure the renovated drainage pipe, obtain the final basic information, update the drainage system diagram, and hand over the drainage system diagram and drainage pipe together for subsequent operation and maintenance.

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