Dynamic accounting method for collection efficiency of municipal sewage pipe network facing sewage plant service area

Abstract

This invention relates to a dynamic calculation method for the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas, encompassing the fields of environmental engineering and computer science. The invention aims to address the problem of large errors in calculating the collection efficiency of urban sewage pipe networks using coefficient formulas. It extracts population heat map data and calculates the hourly population of the sewage treatment plant service area using ArcGIS statistical tools. Based on data from the Second National Pollution Source Census, it differentiates per capita pollution production in different regions, and calculates the hourly per capita pollution production in the sewage treatment plant service area by referencing the functional relationship between monthly per capita pollution production and temperature, and the 24-hour variation pattern of hourly per capita pollution production. Based on dynamic hourly population, hourly per capita pollution production, and sewage treatment plant influent monitoring data, it calculates the collection rate of different pollutants in the sewage treatment plant service area. Through weighted calculation, it achieves dynamic calculation of the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas, thereby guiding strategies for improving the quality and efficiency of sewage pipe networks.

Description

Technical Field

[0001] This invention belongs to the field of environmental engineering and computer technology, and particularly relates to sewage pipe network efficiency calculation technology. Background Technology

[0002] As water pollution control efforts deepen, the focus has gradually shifted from improving the treatment efficiency of wastewater treatment plants and controlling effluent discharge to improving the collection efficiency of wastewater pipe networks and controlling direct discharge of wastewater. Proposing a zoned, precise, and efficient method for quantifying the collection efficiency of urban wastewater pipe networks is fundamental to effectively improving their collection efficiency and provides important guidance for accurately addressing the imbalances and inadequacies in urban wastewater pipe networks.

[0003] The key to calculating the efficiency of urban sewage pipe network collection lies in the precise calculation of pollutant collection rate, which is typically achieved using a coefficient formula method. Currently, most calculations define the scope of pollutant collection rate based on provincial or municipal administrative divisions. While the calculation results can serve as a basis for assessing urban sewage collection work in each province and city, the large scope fails to meet the need for precise identification of low collection rates. Furthermore, the per capita pollution generation in the coefficient formula is usually selected based on the range given in the "Outdoor Drainage Design Code," lacking specific selection criteria for different regions. This makes it difficult to accurately reflect regional differences in sewage discharge and quality caused by variations in industrial layout, dietary structure, urbanization, and aging populations. Studies using sewage treatment plant service areas as the calculation scope usually involve long-term hourly water volume and quality measurements of typical residential buildings or communities within the service area. The per capita pollution generation, which reflects the drainage characteristics of the service area and is relatively accurate, is calculated based on the monitoring results. However, this monitoring requires significant time, material, and financial resources, making it difficult to extend to all regions nationwide. Furthermore, the fixed value of the sewage discharge population in the coefficient formula ignores the separation of living and production caused by the frequent and large-scale population movement between service areas, and the cross-regional water use and sewage discharge, which can easily lead to large errors. Summary of the Invention

[0004] This invention aims to solve the problem of large errors in calculating the collection efficiency of urban sewage pipe networks using the coefficient formula method. It provides a dynamic calculation method for the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas.

[0005] The dynamic accounting method for the collection efficiency of urban sewage pipe networks serving sewage treatment plant service areas includes the following steps:

[0006] Step 1: Extract population heat map data of the towns and cities within the service area of ​​the wastewater treatment plant for each period, and calculate the dynamic population of the service area of ​​the wastewater treatment plant for each period based on the population heat map data;

[0007] Step 2: Calculate the daily per capita pollution generation of the wastewater treatment plant service area based on the pollution generation coefficient of the area where the wastewater treatment plant service area is located. Then, correct the daily per capita pollution generation of the wastewater treatment plant service area and calculate the hourly per capita pollution generation of the wastewater treatment plant service area based on the corrected daily per capita pollution generation.

[0008] Step 3: Calculate the total hourly pollution output of the wastewater treatment plant service area based on the dynamic population of the wastewater treatment plant service area under each cycle as described in Step 1 and the hourly per capita pollution output of the wastewater treatment plant service area as described in Step 2, and calculate the daily pollutant collection rate of the wastewater treatment plant service area according to the coefficient formula method.

[0009] Step 4: Calculate the daily collection efficiency of the urban sewage pipe network based on the weighted average of the daily pollutant collection rate of the sewage treatment plant service area as described in Step 3.

[0010] Furthermore, in step one above, Python programming software is used to extract population heat data of the towns within the service area of ​​the sewage treatment plant for each cycle.

[0011] Furthermore, in step one above, the population heat map data of the towns within the sewage treatment plant service area for each period is imported into ArcGIS software. The total number of population distribution points within the towns within the sewage treatment plant service area for each period and the total number of population distribution points within the sewage treatment plant service area for each period are statistically obtained. The dynamic population of the sewage treatment plant service area for each period is then obtained using the following formula:

[0012]

[0013] Among them, P w,j Let N be the dynamic population of the wastewater treatment plant service area during the j-th period. w,j N represents the total number of population distribution points within the service area of ​​the wastewater treatment plant during the j-th period. t,j P represents the total number of population distribution points within the urban area served by the wastewater treatment plant during the j-th period. t This refers to the total permanent resident population of the town or city within the service area of ​​the sewage treatment plant.

[0014] Furthermore, in step two above, the daily per capita wastewater production in the wastewater treatment plant service area is calculated using the following formula:

[0015] PPG d,i =PQ×k×C i ,

[0016] Among them, PPG d,i Let PQ be the daily per capita output of the i-th pollutant in the wastewater treatment plant service area, k be the pollution reduction coefficient, and C be the daily per capita domestic water consumption in the wastewater treatment plant service area. i The concentration of the i-th pollutant in the domestic sewage from the sewage treatment plant's service area.

[0017] Furthermore, in step two above, the daily per capita wastewater production in the wastewater treatment plant service area is corrected according to the following formula:

[0018]

[0019] Among them, PPG d,i,m To correct the daily per capita output of the i-th pollutant in the wastewater treatment plant service area, T m To calculate the average temperature of the month to which the date belongs, T a To calculate the average temperature of the year to which the date belongs, T max To calculate the highest temperature of the year to which the date belongs, T min The lowest temperature of the year to which the calculation date belongs, and r is a dimensionless coefficient.

[0020] Furthermore, in step two above, the hourly per capita wastewater production in the wastewater treatment plant service area is calculated using the following formula:

[0021]

[0022] Among them, PPG h,i,m,j For the per capita production of pollutant i in the wastewater treatment plant service area during hour j, PPG l,j The per capita pollution output for the j-th hour is obtained through literature review.

[0023] Furthermore, in step three above, the total hourly wastewater production of the wastewater treatment plant's service area is calculated using the following formula:

[0024] PG h,i,m,j =PPG h,i,m,j ×P w,j ,

[0025] Among them, PG h,i,m,j Let P be the total amount of pollutant i generated in the service area of ​​the wastewater treatment plant during the j-th hour of the j-th cycle. w,j Let PPG represent the dynamic population of the wastewater treatment plant service area during the j-th period. h,i,m,j The per capita output of pollutant i in the service area of ​​the wastewater treatment plant during hour j.

[0026] Furthermore, in step three above, the daily pollutant collection rate of the wastewater treatment plant service area is calculated according to the following formula:

[0027]

[0028] Where, η i Q represents the daily collection rate of the i-th pollutant in the wastewater treatment plant service area. w C represents the daily influent volume of the wastewater treatment plant. w,i Let be the average concentration of the i-th pollutant in the daily influent of the wastewater treatment plant.

[0029] Furthermore, in step four above, the daily collection efficiency of the urban sewage pipe network is calculated using the following weighted formula:

[0030] E=∑w i ×η i ,

[0031] Where E represents the daily collection efficiency of all pollutants in the urban sewage pipe network, w i Let be the normalized weight of the i-th pollutant, and we have:

[0032]

[0033] Among them, w o,i Let ∑w be the baseline weight for the i-th pollutant. o,i This represents the baseline weighted sum of all pollutants.

[0034] Furthermore, following step four, step five is also included:

[0035] Determine the correlation between the daily collection efficiency of the urban sewage pipe network and the daily rainfall as described in step four. If the correlation is strong, there are one or more problems in the sewage treatment plant service area, such as rainwater pipes being connected to sewage pipes, rainwater intrusion, and groundwater seepage. If the correlation is weak, there may be one or more problems in the sewage treatment plant service area, such as direct sewage discharge, sewage pipes being connected to rainwater pipes, and insufficient sewage pipe network coverage.

[0036] This invention proposes a dynamic calculation method for the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas. Its main advantages are reflected in the following aspects:

[0037] 1. A method for calculating hourly per capita pollution generation considering regional differences, climate characteristics, and drainage features is proposed. The functional relationship between monthly per capita pollution generation and temperature reflects the influence of climate; the 24-hour variation pattern of hourly per capita pollution generation reflects drainage characteristics. Compared with traditional parameter selection, this method has smaller errors and can reflect the spatiotemporal characteristics of per capita pollution generation; compared with actual measurement, it reduces the time consumption and capital investment in monitoring equipment.

[0038] 2. A dynamic accounting method for regional pollution generation under the background of population mobility is proposed. Based on the population heat map, the dynamic hourly population of the sewage treatment plant service area is calculated, which solves the problem of difficulty in accurately quantifying regional pollution generation caused by cross-regional water use and sewage discharge due to population mobility, and provides support for the dynamic accounting of pollutant collection rate in sewage treatment plant service areas.

[0039] 3. A method for calculating the collection efficiency of urban sewage pipe networks based on the collection rate of different pollutants is proposed. This method is more convincing than evaluating the collection efficiency of sewage pipe networks using the collection rate of a single pollutant. Moreover, it can be adjusted according to the quality of the influent monitoring data of sewage treatment plants and shows better tolerance for partial missing or abnormal monitoring data.

[0040] 4. A comprehensive process method for decision-making on improving the quality and efficiency of urban sewage pipe networks is proposed, which realizes the calculation of the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas, the analysis of the calculation results, and the proposal of quality and efficiency improvement strategies. This helps urban managers make systematic and scientific decisions on sewage pipe networks. Attached Figure Description

[0041] Figure 1 A flowchart for a dynamic calculation method of urban sewage pipe network collection efficiency for sewage treatment plant service areas;

[0042] Figure 2 This is a real-time population distribution map of City S in Implementation Method 2. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0044] The pollutant indicators involved in this implementation method are selected from the "Second National Pollution Source Census Domestic Pollution Source Production and Discharge Coefficient Manual" and the main monitoring indicators of wastewater influent to sewage treatment plants in my country, namely chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH3-N).

[0045] Specific implementation method one: Refer to Figure 1 This embodiment of the method for dynamically calculating the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas includes the following steps:

[0046] Step 1: Extract population heat map data for the towns within the wastewater treatment plant's service area for each period, and calculate the dynamic population of the wastewater treatment plant's service area for each period based on this population heat map data. Details are as follows:

[0047] Population heat maps dynamically reflect the degree of population concentration in a given space using different colors and brightness levels, updating every hour to track changes in population density throughout the day. However, population heat maps are typically image data that has undergone data rendering and cannot directly display or display population activity. Therefore, this implementation method utilizes Python programming software for data mining to extract population heat map data for the towns within the wastewater treatment plant's service area for each period, specifically the hourly population distribution data for the towns within the wastewater treatment plant's service area within the calculation time frame.

[0048] Population heatmap data for the towns within the wastewater treatment plant's service area for each period were imported into ArcGIS software. ArcGIS was then used to statistically analyze the total number of population distribution points within the towns within the wastewater treatment plant's service area for each period. The "Count Polygon Points" function in ArcGIS was then used to obtain the total number of population distribution points within the wastewater treatment plant's service area for each period. The dynamic population of the wastewater treatment plant's service area for each period was then calculated using the following formula:

[0049]

[0050] Among them, P w,j Let N be the dynamic population of the wastewater treatment plant service area during the j-th period. w,j N represents the total number of population distribution points within the service area of ​​the wastewater treatment plant during the j-th period. t,j P represents the total number of population distribution points within the urban area served by the wastewater treatment plant during the j-th period. t This refers to the total permanent resident population of the town or city within the service area of ​​the sewage treatment plant.

[0051] Step Two: Calculate the daily per capita pollution generation of the wastewater treatment plant's service area based on the pollution generation coefficient of the area. Then, correct the daily per capita pollution generation of the service area and calculate the hourly per capita pollution generation of the service area based on the corrected daily per capita pollution generation. Details are as follows:

[0052] Considering geographical environment, economic level, climate characteristics, and water consumption and drainage features, the measured area is divided into six regions. Based on differences in administrative divisions, economic level, tertiary industry proportion, per capita water consumption, and sewage discharge characteristics, the urban area is further divided into urban districts of relatively developed cities, urban districts of general cities, county towns, and townships. Therefore, based on the location of the sewage treatment plant's service area, the regional and urban classifications can be determined. A pollution generation coefficient with regional characteristics is selected, and the daily per capita pollution generation of the sewage treatment plant's service area is calculated using the following formula:

[0053] PPG d,i =PQ×k×C i ,

[0054] Among them, PPG d,iLet be the daily per capita output of the i-th pollutant in the wastewater treatment plant service area. In this embodiment, i = 1, 2, 3, 4, 5, representing the five pollutants: chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TNO), total phosphorus (TP), and ammonia nitrogen (NHN). PQ is the daily per capita domestic water consumption in the wastewater treatment plant service area. k is the pollution reduction coefficient. When the per capita daily domestic water consumption is ≤150 L / (person·d), k = 0.8; when the per capita daily domestic water consumption is ≥250 L / (person·d), k = 0.9; when the per capita daily domestic water consumption is between 150 L / (person·d) and 250 L / (person·d), k is determined by interpolation. C i The concentration of the i-th pollutant in the domestic sewage from the sewage treatment plant's service area.

[0055] Per capita pollution generation is related to climate factors. Hot summer weather increases water demand, leading to a greater per capita pollution generation. Per capita pollution generation fluctuates monthly and can be considered a function of temperature. Therefore, the daily per capita pollution generation in the wastewater treatment plant service area is adjusted for different months to reflect the climatic characteristics of pollution generation. The daily per capita pollution generation in the wastewater treatment plant service area is adjusted according to the following formula:

[0056]

[0057] Among them, PPG d,i,m This represents the daily per capita production of the i-th pollutant in the service area of ​​the wastewater treatment plant after correction. m This refers to the average temperature of the month to which the calculation date belongs. (T) a This refers to the average temperature of the year to which the calculation date belongs. (T) max This refers to the highest temperature of the year to which the calculation date belongs. (T) min The lowest temperature of the year to which the calculation date belongs. r is a dimensionless coefficient used to measure the relative difference in per capita pollution production between the warmest and coldest months, usually taken as 0.2.

[0058] Many regions have conducted scientific research and related projects on the source generation and patterns of domestic sewage pollutants in typical residential buildings or communities. By conducting literature reviews and collecting project data, the 24-hour variation patterns of hourly per capita sewage generation in towns or areas with similar geographical locations and economic development levels within the sewage treatment plant's service area were obtained as a reference. The hourly per capita sewage generation in the sewage treatment plant's service area was then calculated to reflect the drainage characteristics. The hourly per capita sewage generation in the sewage treatment plant's service area was calculated using the following formula:

[0059]

[0060] Among them, PPG h,i,m,j For the per capita production of pollutant i in the wastewater treatment plant service area during hour j, PPG l,j The per capita pollution output for the j-th hour is obtained through literature review.

[0061] Step 3: Based on the dynamic population size of the wastewater treatment plant service area under each cycle described in Step 1 and the hourly per capita wastewater production of the wastewater treatment plant service area described in Step 2, calculate the total hourly wastewater production of the wastewater treatment plant service area, and calculate the daily pollutant collection rate of the wastewater treatment plant service area using the coefficient formula method. This step, by introducing dynamic hourly population data, solves the problem of large errors in calculating regional wastewater production caused by frequent and large-scale population movement between wastewater treatment plant service areas, which leads to separation of living and production activities, cross-regional water use and sewage discharge. Details are as follows:

[0062] The total hourly wastewater production of the wastewater treatment plant's service area is calculated using the following formula:

[0063] PG h,i,m,j =PPG h,i,m,j ×P w,j ,

[0064] Among them, PG h,i,m,j This represents the total amount of pollutant i generated in the service area of ​​the wastewater treatment plant during the j-th hour of the j-th cycle.

[0065] The daily pollutant collection rate of the wastewater treatment plant service area is calculated using the following formula:

[0066]

[0067] Where, η i Q represents the daily collection rate of the i-th pollutant in the wastewater treatment plant service area. w C represents the daily influent volume of the wastewater treatment plant. w,i Let be the average concentration of the i-th pollutant in the daily influent of the wastewater treatment plant.

[0068] Step 4: Calculate the daily collection efficiency of the urban sewage pipe network based on the weighted average of the daily pollutant collection rate of the sewage treatment plant service area as described in Step 3. Details are as follows:

[0069] The daily collection efficiency of urban sewage pipe networks is calculated using the following weighted formula:

[0070] E=∑w i ×η i ,

[0071] Where E represents the daily collection efficiency of all pollutants in the urban sewage pipe network, w i Let be the normalized weight of the i-th pollutant.

[0072] Using a comprehensive evaluation of urban sewage pipe network collection efficiency using multiple pollutant collection rates is more reasonable than using a single pollutant collection rate. Due to factors such as monitoring equipment malfunctions, some influent monitoring indicators at sewage treatment plants may have missing or outlier values. Therefore, it is necessary to select available and effective pollutant indicators based on the actual quality of the monitoring data, and normalize the collection rate benchmark weight of the selected indicators. The normalized weight calculation formula for the i-th pollutant is as follows:

[0073]

[0074] In the formula, w o,i As the baseline weight for the i-th pollutant, referring to the calculation formula for pollutant collection efficiency scores in the "Interim Measures for the Assessment of Urban Sewage Treatment Work," the baseline weights for the collection rates of chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TNO), total phosphorus (TP), and ammonia nitrogen (NH3) are set to 0.2, 0.5, 0.1, 0.1, and 0.1, respectively. These values ​​reflect the increasing emphasis on BOD concentration in sewage treatment plant influent. o,i This represents the baseline weighted sum of all pollutants.

[0075] Step 5: Determine the correlation between the daily collection efficiency of the urban sewage pipe network and the daily rainfall as described in Step 4. If the correlation is strong, rainfall will significantly reduce the collection efficiency of the sewage pipe network, indicating that there are one or more problems in the sewage treatment plant service area, such as rainwater pipes being connected to sewage pipes, rainwater intrusion, and groundwater seepage.

[0076] If the two are not strongly correlated, but the sewage pipe network has low collection efficiency, then there may be one or more problems in the sewage treatment plant service area, such as direct sewage discharge, sewage pipes being mixed with rainwater pipes, and insufficient sewage pipe network coverage.

[0077] Guided by the aforementioned potential problems, the focus is on improving the quality and efficiency of the urban sewage pipe network in the service area of ​​this sewage treatment plant. By calculating the collection efficiency of sewage pipe networks in all sewage treatment plant service areas within the town, key problem areas with low sewage collection efficiency are identified through comparison. When formulating strategies for improving the quality and efficiency of the urban sewage pipe network, priority is given to adding, inspecting, and repairing sewage pipe networks in these key problem areas.

[0078] This implementation proposes a dynamic calculation method for the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas. It extracts population heat map data and calculates the hourly population of the sewage treatment plant service area using ArcGIS statistical tools. Based on data from the Second National Pollution Source Census, it differentiates per capita pollution production in different regions and calculates the hourly per capita pollution production in the sewage treatment plant service area by referring to the functional relationship between monthly per capita pollution production and temperature, and the 24-hour variation pattern of hourly per capita pollution production. Based on dynamic hourly population, hourly per capita pollution production, and sewage treatment plant influent monitoring data, it calculates the collection rate of different pollutants in the sewage treatment plant service area. Through weighted calculation, it achieves dynamic calculation of the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas, thereby guiding strategies for improving the quality and efficiency of sewage pipe networks. This invention realizes the calculation of sewage pipe network collection efficiency in sewage treatment plant service areas that fully considers regional differences, climate characteristics, and drainage features, providing important support for the investigation, renovation, and system management of urban sewage pipe networks.

[0079] Specific Implementation Method Two: Refer to Figure 2This embodiment describes a dynamic calculation method for the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas. This method is applied to the dynamic calculation of the collection efficiency of urban sewage pipe networks in five sewage treatment plant service areas in the G watershed of City S from May 2020 to October 2022. The specific implementation process is as follows:

[0080] (1) Dynamic hourly population accounting of sewage treatment plant service area

[0081] This implementation method obtains the hourly population heatmaps of City S on September 6, 2021, using Baidu Heatmap. It then utilizes Python programming software to perform data mining on the population heatmaps, extracting population heatmap data. The extraction results are as follows: Figure 2 As shown.

[0082] Population heatmap data for each hour of the 24-hour period on September 6, 2021, for City S were imported into ArcGIS. ArcGIS statistical tools were used to count the total number of points within the area of ​​City S. The "Count Polygon Points" function in ArcGIS analysis tools was then used to obtain the total number of points within the service area of ​​Wastewater Treatment Plant B. Based on this, the dynamic hourly population of the wastewater treatment plant service area can be calculated. The calculation formula is as follows:

[0083]

[0084] Among them, P w,j Let N represent the dynamic population size of the wastewater treatment plant's service area during the j-th period. w,j N represents the total number of population distribution points within the service area of ​​the wastewater treatment plant during the j-th period. t,j P represents the total number of population distribution points within the urban area served by the wastewater treatment plant during the j-th period. t The total permanent resident population of the town within the service area of ​​the sewage treatment plant is 17.682 million, according to the statistical yearbook.

[0085] The dynamic hourly population calculation results for the service area of ​​Wastewater Treatment Plant B on September 6, 2021 are shown in Table 1:

[0086] Table 1. Population of Wastewater Treatment Plant Service Area as of September 6, 2021 (24 hours)

[0087] Hour B Wastewater Treatment Plant Service Area Points S City Points Number of people in the service area of ​​Wastewater Treatment Plant B 1 7265 222609 577064 2 4656 146544 561793 3 3038 99594 539369 4 2269 76131 526992 5 1730 63983 478094 6 1606 59350 478472 7 2300 88657 458718 8 6114 222501 485875 9 10997 364117 534029 10 12778 376207 600575 11 11693 399469 517576 12 11359 400627 501339 13 12559 420435 528187 14 11469 369304 549127 15 11751 386200 538014 16 11787 405594 513858 17 11620 400598 512895 18 12404 416372 526759 19 13807 458452 532521 20 13808 433575 563116 21 13168 422515 551073 22 12659 396592 564400 23 11877 367237 571863 24 9866 308331 565790 .

[0088] (2) Calculation of per capita hourly pollution generation in the service area of ​​the sewage treatment plant

[0089] Referring to the "Handbook of Pollution Generation and Discharge Coefficients of Domestic Pollution Sources in the Second National Pollution Source Census," the service area of ​​Wastewater Treatment Plant B is located in a relatively developed urban area of ​​District 5. A pollution generation coefficient with regional characteristics is selected to calculate the daily per capita pollution generation in the service area of ​​the wastewater treatment plant. The calculation formula is as follows:

[0090] PPG d,i =PQ×k×C i ,

[0091] In the formula, PPG d,i The daily per capita wastewater production in the service area of ​​Wastewater Treatment Plant B is represented by i = 1, 2, 3, 4, 5, which represent chemical oxygen demand (COD), biochemical oxygen demand (BOD), total nitrogen (TNO), total phosphorus (TP), and ammonia nitrogen (NHN), respectively; PQ is the daily per capita domestic water consumption in the service area of ​​Wastewater Treatment Plant B, and based on the per capita water consumption data published by the S City Water Resources Bureau, the upper limit of 419 L / (person·d) from the coefficient manual is selected; k is the wastewater conversion coefficient, which is taken as 0.9; C i The pollutant concentrations of domestic wastewater in the service area of ​​Wastewater Treatment Plant B are taken as the average values ​​from the coefficient manual. The values ​​for Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Nitrogen (TNO), Total Phosphorus (TP), and Ammonia Nitrogen (AMN) are taken as 300, 135, 32.6, 4.14, and 23.6 mg / L, respectively. The calculated per capita daily production of COD, BNOD, TNO, TPN, and AMN in the service area of ​​Wastewater Treatment Plant B are 113.13, 50.91, 12.29, 1.56, and 8.90 g, respectively.

[0092] The average monthly pollution output per capita can be considered a function of temperature. Based on this, the average daily pollution output per capita in different months in the service area of ​​Wastewater Treatment Plant B is adjusted to reflect the climatic characteristics of pollution output. The adjusted formula is as follows:

[0093]

[0094] In the formula, PPG d,i,m The revised per capita pollution generation in the service area of ​​Wastewater Treatment Plant B; T m The average temperature in City S in September 2021 was 30.16 degrees Celsius. a The average temperature in City S in 2021 was 24.45 degrees Celsius. max The highest temperature recorded in City S in 2021 was 33.13 degrees Celsius. min The lowest temperature in City S in 2021 was 6.64 degrees Celsius; r is a dimensionless coefficient, taken as 0.2. The per capita production of chemical oxygen demand, biochemical oxygen demand, total nitrogen, total phosphorus, and ammonia nitrogen in the service area of ​​Wastewater Treatment Plant B as of September 6, 2021, was calculated to be 118.01 g, 53.10 g, 12.82 g, 1.63 g, and 9.28 g, respectively.

[0095] By conducting a literature review to obtain the 24-hour variation pattern of hourly per capita pollution generation in a certain community in City N, which has a similar geographical location and economic development level to City S, we used this data as a reference to calculate the hourly per capita pollution generation in the service area of ​​Wastewater Treatment Plant B, in order to reflect the drainage characteristics. The calculation formula is as follows:

[0096]

[0097] In the formula, PPG h,i,m,j Per capita hourly wastewater production at Wastewater Treatment Plant B service area; PPG l,j The hourly per capita pollution generation of a certain community in City N is shown in Table 2. The calculated hourly per capita pollution generation of the B wastewater treatment plant service area on September 6, 2021 is shown in Table 2.

[0098] Table 2B: Per Capita Wastewater Production per Hour in the Wastewater Treatment Plant Service Area on September 6, 2021

[0099]

[0100] (3) Calculation of total hourly wastewater production and daily pollutant collection rate in the service area of ​​the wastewater treatment plant

[0101] Based on the dynamic hourly population of the B wastewater treatment plant service area calculated in (1) and the hourly per capita pollution production of the B wastewater treatment plant service area calculated in (2), the total hourly pollution production of the B wastewater treatment plant service area is calculated using the following formula:

[0102] PG h,i,m,j =PPG h,i,m,j ×P w,j ,

[0103] In the formula, PG h,i,m,j This represents the total hourly pollution generation of the B wastewater treatment plant service area. The hourly pollution generation calculation results for the B wastewater treatment plant service area on September 6, 2021 are shown in Table 3.

[0104] Table 3 Total wastewater generation per hour in the service area of ​​Wastewater Treatment Plant B on September 6, 2021 (24 hours)

[0105]

[0106]

[0107] The daily pollutant collection rate of the service area of ​​Wastewater Treatment Plant B is calculated using the following formula:

[0108]

[0109] In the formula, η i Daily pollutant collection rate of the service area of ​​Wastewater Treatment Plant B; Q w The daily influent volume of wastewater treatment plant B; C w,iLet be the average daily influent pollutant concentration of Wastewater Treatment Plant B. The calculated collection rates for Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Nitrogen (TN), Total Phosphorus (TP), and Ammonia Nitrogen (AM) in the service area of ​​Wastewater Treatment Plant B on September 6, 2021, were 54.20%, 54.88%, 73.85%, 54.96%, and 65.46%, respectively.

[0110] (4) Efficiency calculation of urban sewage pipe network collection in sewage treatment plant service area

[0111] The collection efficiency of the urban sewage pipe network is calculated by weighting the collection rates of different pollutants in the service area of ​​Wastewater Treatment Plant B based on the calculation in step (3). The calculation formula is as follows:

[0112] E=∑w i ×η i ,

[0113] In the formula, E represents the daily collection efficiency of the urban sewage pipe network in the service area of ​​sewage treatment plant B; w i Let be the normalized weight for the collection rate of the i-th pollutant. Since the influent monitoring data of Wastewater Treatment Plant B on September 6, 2021, was of good quality, with no missing or outlier values ​​for any of the five pollutant indicators, all five indicators were selected. The normalized weights for the collection rates of Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Total Nitrogen (TN), Total Phosphorus (TP), and Ammonia Nitrogen (AM) were 0.2, 0.5, 0.1, 0.1, and 0.1, respectively. The calculated collection efficiency of the urban sewage pipe network in the service area of ​​Wastewater Treatment Plant B on September 6, 2021, was 0.577.

[0114] (5) Guide the formulation of strategies for improving the quality and efficiency of urban sewage pipe networks

[0115] Referring to steps (1) to (4), calculate the daily collection efficiency of the urban sewage pipe network in the service area of ​​Wastewater Treatment Plant B from May 2020 to October 2022. Calculate the Pearson correlation coefficient between the daily collection efficiency of the urban sewage pipe network in the service area of ​​Wastewater Treatment Plant B and the daily rainfall. The result is -0.102, indicating a weak negative correlation. Rainfall will not significantly reduce the collection efficiency of the sewage pipe network. This suggests that the probability of problems such as rainwater pipes being mixed with sewage pipes, rainwater intrusion, and groundwater seepage in the service area of ​​Wastewater Treatment Plant B is relatively low. However, the low collection efficiency of the sewage pipe network indicates that there may be problems such as direct sewage discharge, sewage pipes being mixed with rainwater pipes, and insufficient sewage pipe network coverage in the service area of ​​Wastewater Treatment Plant B. Guided by the potential problems, highlight the key tasks for improving the quality and efficiency of the urban sewage pipe network in the service area of ​​Wastewater Treatment Plant B, such as investigating blank areas in the sewage pipe network of the service area of ​​Wastewater Treatment Plant B, investigating the connection of sewage from washing clothes on residents' balconies, and investigating the condition of outdoor risers.

[0116] Based on the calculation of the sewage pipe network collection efficiency of the five sewage treatment plant service areas in the G watershed, the sewage pipe network collection efficiency of the E sewage treatment plant service area is the lowest. Therefore, the sewage pipe network of the E sewage treatment plant service area should be prioritized for addition, inspection and repair.

[0117] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. A dynamic accounting method for the collection efficiency of urban sewage pipe networks in sewage treatment plant service areas, characterized in that, Includes the following steps: Step 1: Extract population heat map data of the towns and cities within the service area of ​​the wastewater treatment plant for each period, and calculate the dynamic population of the service area of ​​the wastewater treatment plant for each period based on the population heat map data; Step 2: Calculate the daily per capita pollution generation of the wastewater treatment plant service area based on the pollution generation coefficient of the area where the wastewater treatment plant service area is located. Then, correct the daily per capita pollution generation of the wastewater treatment plant service area and calculate the hourly per capita pollution generation of the wastewater treatment plant service area based on the corrected daily per capita pollution generation. Step 3: Calculate the total hourly pollution output of the wastewater treatment plant service area based on the dynamic population of the wastewater treatment plant service area under each cycle as described in Step 1 and the hourly per capita pollution output of the wastewater treatment plant service area as described in Step 2, and calculate the daily pollutant collection rate of the wastewater treatment plant service area according to the coefficient formula method. Step 4: Calculate the daily collection efficiency of the urban sewage pipe network based on the weighted average of the daily pollutant collection rate of the sewage treatment plant service area as described in Step 3; In step one, the population heat map data of the towns within the sewage treatment plant service area for each period is imported into ArcGIS software. The total number of population distribution points within the towns within the sewage treatment plant service area for each period and the total number of population distribution points within the sewage treatment plant service area for each period are statistically obtained. The dynamic population of the sewage treatment plant service area for each period is then obtained using the following formula: ， in, For the first Dynamic population size in the service area of ​​the wastewater treatment plant during the cycle. For the first The total number of population distribution points within the service area of ​​the wastewater treatment plant during the cycle. For the first The total number of population distribution points within the urban area served by the wastewater treatment plant during the cycle. The total resident population of the town within the service area of ​​the sewage treatment plant; In step two, the daily per capita wastewater production in the wastewater treatment plant service area is corrected according to the following formula: ， in, For the revised sewage treatment plant service area The daily per capita output of the pollutants, Service area for sewage treatment plant The daily per capita output of the pollutants, To calculate the average temperature of the month to which the calculation date belongs, To calculate the average temperature of the year to which the date belongs, To calculate the highest temperature of the year to which the date belongs, To calculate the lowest temperature of the year to which the calculation date belongs, The coefficient is dimensionless. In step four, the daily collection efficiency of the urban sewage pipe network is calculated using the following weighted formula: ， in, To improve the daily collection efficiency of all pollutants in urban sewage pipe networks, Service area for sewage treatment plant Daily collection rate of various pollutants For the first The normalized weights of the pollutants are: ， in, For the first The benchmark weights of various pollutants, This represents the baseline weighted sum of all pollutants.

2. The method for dynamic calculation of urban sewage pipe network collection efficiency for sewage treatment plant service areas according to claim 1, characterized in that, In step one, Python programming software is used to extract population heat data of the towns within the service area of ​​the sewage treatment plant for each cycle.

3. The method for dynamic calculation of urban sewage pipe network collection efficiency for sewage treatment plant service areas according to claim 1, characterized in that, In step two, the daily per capita wastewater production in the wastewater treatment plant service area is calculated using the following formula: ， in, The average daily domestic water consumption per person in the service area of ​​the sewage treatment plant. This is the pollution reduction factor. The first type of sewage from domestic sources in the service area of ​​the sewage treatment plant The concentration of various pollutants.

4. The method for dynamic calculation of urban sewage pipe network collection efficiency for sewage treatment plant service areas according to claim 1 or 3, characterized in that, In step two, the hourly per capita wastewater production in the wastewater treatment plant service area is calculated according to the following formula: ， in, Service area for sewage treatment plant The pollutants in the first Per capita output per hour The first one found through literature search Per capita pollution production per hour.

5. The method for dynamic calculation of urban sewage pipe network collection efficiency for sewage treatment plant service areas according to claim 1, characterized in that, In step three, the total hourly pollution generation of the wastewater treatment plant service area is calculated according to the following formula: ， in, For the first Wastewater treatment plant service area during cycle The first hour produced The total amount of various pollutants, For the first Dynamic population size in the service area of ​​the wastewater treatment plant during the cycle. Service area for sewage treatment plant The pollutants in the first Per capita output per hour.

6. The method for dynamic calculation of urban sewage pipe network collection efficiency for sewage treatment plant service areas according to claim 5, characterized in that, In step three, the daily pollutant collection rate of the wastewater treatment plant service area is calculated according to the following formula: ， in, This represents the daily influent volume of the wastewater treatment plant. The first day of influent to the sewage treatment plant The average concentration of various pollutants.

7. The method for dynamic calculation of urban sewage pipe network collection efficiency for sewage treatment plant service areas according to claim 1, 2, 3, 5 or 6, characterized in that, Following step four, step five is also included: Determine the correlation between the daily collection efficiency of the urban sewage pipe network and the daily rainfall as described in step four. If the correlation is strong, there are one or more problems in the sewage treatment plant service area, such as rainwater pipes being connected to sewage pipes, rainwater intrusion, and groundwater seepage. If the correlation is weak, there may be one or more problems in the sewage treatment plant service area, such as direct sewage discharge, sewage pipes being connected to rainwater pipes, and insufficient sewage pipe network coverage.

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