SWMM-based sewage pipeline BOD (Biochemical Oxygen Demand) biological action degradation amount detection method and system

Abstract

The invention discloses a sewage pipeline BOD biological action degradation amount detection method and system based on an SWMM model. The method comprises the following steps that a sewage pipe network model of a to-be-detected area is established in the SWMM model; arranging a plurality of monitoring points in an inspection well of the sewage pipeline in the to-be-detected area, and acquiring flow data, flow velocity data and liquid level data of the plurality of monitoring points; the flow data and the liquid level data are input into the sewage pipe network model, and the average wetted perimeter area of each pipe section in the monitoring time period is obtained; at least one pipe section is selected, and the methane yield and the hydrogen sulfide yield of the pipe section are obtained based on the average wetted perimeter area of the pipe section; and calculating the BOD biological action degradation amount of the sewage pipeline based on the methane yield, the hydrogen sulfide yield and the average wetted perimeter area of each pipe section. The method solves the problem that a current calculation method for the BOD biological action degradation amount of the sewage pipeline is not accurate.

Description

Technical Field

[0001] The present invention belongs to the technical field of drainage engineering, and in particular relates to a method and system for detecting BOD biological degradation amount in a sewage pipe based on SWMM. Background Art

[0003] Urban sewage pipe networks are mostly anaerobic or anoxic environments. The organic matter carried in them will generate methane and hydrogen sulfide through the action of microorganisms on the surface of the biofilm in the pipe network, thereby consuming the BOD in the sewage. At present, there is still a lack of accurate measurement methods for the overall degradation of BOD in sewage pipes. Since the reaction of producing methane and hydrogen sulfide in sewage pipes only occurs on the surface of the biofilm, the water quality of sewage in a drainage zone is relatively stable, the microbial population is basically unchanged, and the organic matter and sulfate in the sewage are usually excessive relative to the microorganisms. Therefore, using SWMM software, combined with monitoring the water level, and then measuring the biofilm yield of some representative pipe sections, the BOD biological degradation of sewage when it flows through the pipe section can be calculated based on the area of ​​the wet perimeter of the pipe and the rate of the biofilm reaction. Summary of the invention

[0004] The present invention aims to solve the deficiencies of the prior art and provides the following solutions:

[0005] A method for detecting the biodegradation amount of BOD in a sewage pipe based on SWMM includes the following steps:

[0006] Establishing a sewage pipe network model of the area to be tested in the SWMM model;

[0007] Arrange a plurality of monitoring points in the inspection well of the sewage pipe in the area to be inspected, and obtain flow data, flow velocity data and liquid level data of the plurality of monitoring points;

[0008] Inputting the flow data and the liquid level data into the sewage pipe network model to obtain the average wetted perimeter area of ​​each pipe section during the monitoring period;

[0009] Selecting at least one of the pipe sections, and obtaining a methane yield and a hydrogen sulfide yield of the pipe section based on an average wetted perimeter area of ​​the pipe section;

[0010] The BOD biological degradation amount of the sewage pipe is calculated based on the methane yield, the hydrogen sulfide yield and the average wetted peripheral area of ​​each of the pipe sections.

[0011] Preferably, the method for constructing the sewage pipe network model includes:

[0012] According to the scope of the sewage pipe network in the area to be inspected, obtain the sewage pipe mapping data, inspection well mapping data and pump station mapping data;

[0013] Based on the sewage pipe mapping data, the inspection well mapping data and the pump station mapping data, the sewage pipe network model of the area to be detected is constructed in the SWMM model.

[0014] Preferably, the method for obtaining flow data, flow velocity data and liquid level data of several monitoring points includes:

[0015] Arranging a flow meter in the inspection well, and using the flow meter to obtain the flow data and the flow velocity data;

[0016] A liquid level meter is arranged in the inspection well, and the liquid level data is acquired by using the liquid level meter.

[0017] Preferably, the method for obtaining the average wetted peripheral area of ​​each pipe segment comprises:

[0018] Based on the liquid level data of each pipe segment and in combination with the pipe diameter data of each pipe segment, the dynamic wetted peripheral area of ​​each pipe segment is calculated;

[0019] The average wetted peripheral area of ​​each of the pipe segments is calculated based on the dynamic wetted peripheral area of ​​each of the pipe segments.

[0020] Preferably, the method for calculating the methane yield and the hydrogen sulfide yield comprises:

[0021] Selecting at least one of the pipe sections, and calculating the sampling intervals of the starting inspection well and the end inspection well of the pipe section based on the flow velocity data;

[0022] Based on the sampling interval, collecting water samples from the starting inspection well and the end inspection well;

[0023] Using high performance gas chromatography to detect the methane concentration and hydrogen sulfide concentration in the water sample, and calculating the difference in methane concentration and hydrogen sulfide concentration between upstream and downstream in the pipe section;

[0024] Based on the flow data, the average wetted area, the methane concentration difference and the hydrogen sulfide concentration difference, the methane yield and the hydrogen sulfide yield are calculated:

[0025]

[0026] Wherein, x represents methane or hydrogen sulfide; P x Indicates the methane or hydrogen sulfide yield, g / m 2 / d; ΔC x Indicates the difference in methane concentration or hydrogen sulfide concentration, mg / l; Q indicates the flow rate data, l / s; W indicates the average wetted area, m 2 .

[0027] Preferably, the method of selecting at least one of the pipe sections comprises: selecting at least one sewage pipe with a distance of more than 100m and no branch pipe connected thereto in the area to be detected;

[0028] The method for determining whether the sewage pipe has a branch pipe connected thereto comprises: obtaining the starting flow data and the ending flow data of the sewage pipe, and when the starting flow data and the ending flow data are equal, determining that the sewage pipe has no branch pipe connected thereto.

[0029] Preferably, the method for calculating the BOD biological degradation amount includes:

[0030] Based on the average wetted area, the methane yield and the hydrogen sulfide yield of each pipe section, the methane yield and the hydrogen sulfide yield of each pipe section are calculated:

[0031] M x =P x W

[0032] Wherein, x represents methane or hydrogen sulfide; M x Indicates the methane or hydrogen sulfide production, g / d; P x Indicates the methane or hydrogen sulfide yield, g / m 2 / d; W represents the average wetted area, m 2 .

[0033] Adding the methane production of each pipe section to obtain the total methane volume of the sewage pipe;

[0034] Adding the hydrogen sulfide production of each pipe section to obtain the total amount of hydrogen sulfide in the sewage pipe;

[0035] Based on the total amount of methane and the total amount of hydrogen sulfide, the BOD biological degradation amount is calculated:

[0036]

[0037] in, represents methane production, g / d; Indicates hydrogen sulfide production, g / d; M BOD Indicates BOD production, g / d; n indicates the number of pipe sections.

[0038] The present invention also provides a sewage pipe BOD biological degradation amount detection system based on SWMM, the detection system applies any of the above detection methods, including: a model building module, a data monitoring module, a wetted area calculation module, a yield calculation module and a degradation amount calculation module;

[0039] The model building module is used to establish a sewage pipe network model of the area to be detected in the SWMM model;

[0040] The data monitoring module is used to arrange a number of monitoring points in the inspection well of the sewage pipe in the area to be detected, and obtain flow data, flow velocity data and liquid level data of the monitoring points;

[0041] The wetted area calculation module is used to input the flow data and the liquid level data into the sewage pipe network model to obtain the average wetted area of ​​each pipe section in the monitoring period;

[0042] The yield calculation module is used to select at least one of the pipe sections, and obtain the methane yield and hydrogen sulfide yield of the pipe section based on the average wetted circumference area of ​​the pipe section;

[0043] The degradation amount calculation module calculates the BOD biological degradation amount of the sewage pipe based on the methane yield, the hydrogen sulfide yield and the average wetted peripheral area of ​​each pipe section.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The present invention solves the problem of inaccurate calculation methods for the biological degradation of BOD in sewage pipes. First, by implementing hydraulic simulation of the sewage pipe network through the SWMM model, dynamic liquid level data of all pipe sections can be obtained, and a more accurate wetted area of ​​the pipe can be obtained; secondly, by calculating the methane and hydrogen sulfide production of pipes without branches and external water intrusion, and using the conversion relationship between the two and the biological degradation of BOD to calculate the degradation of BOD, the accuracy and efficiency of the calculation of the biological degradation of BOD are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0047] Figure 1 A schematic diagram of a method flow of an embodiment of the present invention;

[0048] Figure 2 Schematic diagram of a sewage pipe network SWMM model selected in an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of a non-branch pipe section of a sewage pipe network according to an embodiment of the present invention;

[0050] Figure 4 A flow rate, flow velocity, and liquid level change diagram of a starting well of a selected pipe section according to an embodiment of the present invention;

[0051] Figure 5 This is a graph showing changes in methane and hydrogen sulfide concentrations at the starting well and the end well of an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0054] Embodiment 1

[0055] In this embodiment, if Figure 1 As shown, a method for detecting the biodegradation amount of BOD in a sewage pipe based on SWMM includes the following steps:

[0056] S1. Establish a sewage pipe network model of the area to be tested in the SWMM model.

[0057] The method for constructing a sewage pipe network model includes: obtaining sewage pipe mapping data, inspection well mapping data and pump station mapping data according to the scope of the sewage pipe network in the area to be detected; based on the sewage pipe mapping data, inspection well mapping data and pump station mapping data, in this embodiment, the mapping data includes: plane coordinates, elevation coordinates, pipe diameter, pipe material, pump station flow and water pump start time and other attribute data, constructing a sewage pipe network model of the area to be detected in the SWMM model (storm flood management model), such as Figure 2 shown.

[0058] S2. Arrange several monitoring points in the inspection wells of the sewage pipes in the area to be inspected, and obtain flow data, flow velocity data and liquid level data of the several monitoring points.

[0059] The method for obtaining flow data, flow velocity data and liquid level data of several monitoring points includes: arranging a flow meter in the inspection well and obtaining flow data and flow velocity data by using the flow meter; arranging a liquid level meter in the inspection well and obtaining liquid level data by using the liquid level meter.

[0060] S3. Input the flow data and liquid level data into the sewage pipe network model to obtain the average wetted perimeter area of ​​each pipe section during the monitoring period.

[0061] The method for obtaining the average wetted area includes: based on the liquid level data, combined with the pipe diameter data of each pipe section, calculating the dynamic wetted area of ​​each pipe section:

[0062]

[0063] Among them, A j represents the wetted area at time j, m 2 ; D represents the pipe diameter, m; h j represents the liquid level at time j, m; L represents the length of the pipeline, m.

[0064] Calculate the average wetted area of ​​each pipe segment based on the dynamic wetted area:

[0065]

[0066] Among them, A ave Indicates the average wetted area, m 2 ; m represents the total number of all moments.

[0067] In this embodiment, the sum of the average wetted circumference of all pipe sections is 37572 m 2 .

[0068] S4. Select at least one pipe section and obtain the methane yield and hydrogen sulfide yield of the pipe section based on the average wetted area of ​​the pipe section.

[0069] The method for calculating the methane yield and the hydrogen sulfide yield includes: selecting at least one pipe section, and calculating the sampling interval of the starting inspection well and the end inspection well of the pipe section based on the flow rate data. In this embodiment, at least one sewage pipe with a distance of 539m and no branch pipe connected is selected as the pipe section in the area to be detected, such as Figure 3 As shown in the figure, flow meters are placed at the starting inspection well and the end inspection well to measure the sewage flow rate and flow data, and liquid level meters are placed to measure the liquid level data. The flow rate, flow rate, and liquid level changes at the starting point are shown in the figure below. Figure 4 As shown in the figure, based on the pipe length, pipe diameter and liquid level data during sampling, the total wetted area of ​​the pipe section is calculated to be 1324m 2 ; Based on the sampling interval, water samples are collected from the starting inspection well and the terminal inspection well. In this embodiment, a time period with relatively stable flow (9:30-9:50) is selected, and the sampling interval of the starting inspection well and the terminal inspection well is calculated according to the average flow rate (1.45m / s) during this period: 539 / 1.45 / 60≈6min, and a total of 3 times are taken, each water sample is 100ml; the methane concentration and hydrogen sulfide concentration in the water sample are detected by high performance gas chromatography, such as Figure 5 As shown, the methane concentration difference and hydrogen sulfide concentration difference between the upstream and downstream of the pipe section are calculated; based on the flow data, average wetted area, methane concentration difference and hydrogen sulfide concentration difference, the methane yield and hydrogen sulfide yield are calculated:

[0070]

[0071] Wherein, x represents methane or hydrogen sulfide; P x Indicates the methane or hydrogen sulfide yield, g / m 2 / d; ΔC x Indicates the difference in methane concentration or hydrogen sulfide concentration, mg / l; Q indicates the flow rate data, l / s; W indicates the average wetted area, m 2 In this embodiment, the methane and hydrogen sulfide yields of the biofilm in the pipe section were calculated according to the formula based on the wetted area during sampling, which were 11.02 g / m 2 / d and 5.06g / m 2 / d.

[0072] Furthermore, the method for determining whether a branch pipe is connected to the sewage pipe includes: obtaining the starting flow data and the ending flow data of the sewage pipe, and when the starting flow data and the ending flow data are equal, determining that the sewage pipe has no branch pipe connected.

[0073] S5. Calculate the BOD biological degradation amount of the sewage pipe based on the methane yield, hydrogen sulfide yield and average wetted area of ​​each pipe section.

[0074] The method for calculating the BOD biological degradation amount includes: based on the average wetted area, methane yield and hydrogen sulfide yield of each pipe section, the methane yield and hydrogen sulfide yield of each pipe section are calculated:

[0075] M x =P x W

[0076] Wherein, x represents methane or hydrogen sulfide; M x Indicates the methane or hydrogen sulfide production, g / d; P x Indicates the methane or hydrogen sulfide yield, g / m 2 / d; W represents the average wetted area, m 2 .

[0077] The methane production of each pipe section is added to obtain the total methane of the sewage pipe; the hydrogen sulfide production of each pipe section is added to obtain the total hydrogen sulfide of the sewage pipe; in this embodiment, the methane and hydrogen sulfide yields of the obtained biofilm and the average wetted area of ​​each pipe are used to calculate the methane and hydrogen sulfide production of the pipe network to be 414.18 kg / d and 190.04 kg / d respectively. Based on the total methane and hydrogen sulfide, the BOD biological degradation amount is calculated:

[0078]

[0079] in, represents methane production, g / d; Indicates hydrogen sulfide production, g / d; M BOD Indicates BOD production, g / d; n indicates the number of pipe sections.

[0080] In this embodiment, based on the conversion relationship between methane production and hydrogen sulfide production and BOD biological degradation (producing 1 mg of methane is approximately equivalent to degrading 1.86 mg of BOD, and producing 1 mg of hydrogen sulfide is approximately equivalent to degrading 3.61 mg of BOD), the daily average BOD biological degradation of the sewage network in the study area is calculated to be 1456.41 kg / d, divided by the total sewage volume on that day, and the BOD biological degradation in the sewage is obtained to be 45.31 mg / l.

[0081] Embodiment 2

[0082] In this embodiment, a sewage pipe BOD biological degradation detection system based on SWMM includes: a model building module, a data monitoring module, a wetted area calculation module, a yield calculation module and a degradation amount calculation module.

[0083] The model building module is used to establish a sewage network model of the area to be tested in the SWMM model.

[0084] The data monitoring module is used to arrange a number of monitoring points in the inspection wells of the sewage pipes in the area to be detected, and to obtain flow data, flow velocity data and liquid level data of the number of monitoring points.

[0085] The wetted area calculation module is used to input flow data and liquid level data into the sewage pipe network model to obtain the average wetted area of ​​each pipe section during the monitoring period.

[0086] The yield calculation module is used to select no less than one pipe section and obtain the methane yield and hydrogen sulfide yield of the pipe section based on the average wetted peripheral area of ​​the pipe section.

[0087] The degradation amount calculation module calculates the BOD biological degradation amount of the sewage pipe based on the methane yield, hydrogen sulfide yield and average wetted area of ​​each pipe section.

[0088] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for detecting the biodegradation of BOD in sewage pipes based on SWMM, characterized in that: The following steps are involved: Establishing a sewage pipe network model of the area to be tested in the SWMM model; Arrange a plurality of monitoring points in the inspection well of the sewage pipe in the area to be inspected, and obtain flow data, flow velocity data and liquid level data of the plurality of monitoring points; Inputting the flow data and the liquid level data into the sewage pipe network model to obtain the average wetted perimeter area of ​​each pipe section during the monitoring period; Selecting at least one of the pipe sections, and obtaining a methane yield and a hydrogen sulfide yield of the pipe section based on an average wetted perimeter area of ​​the pipe section; The BOD biological degradation amount of the sewage pipe is calculated based on the methane yield, the hydrogen sulfide yield and the average wetted peripheral area of ​​each of the pipe sections.

2. The method for detecting the biodegradation amount of BOD in sewage pipes based on SWMM according to claim 1, characterized in that: The method for constructing the sewage pipe network model includes: According to the scope of the sewage pipe network in the area to be inspected, obtain the sewage pipe mapping data, inspection well mapping data and pump station mapping data; Based on the sewage pipe mapping data, the inspection well mapping data and the pump station mapping data, the sewage pipe network model of the area to be detected is constructed in the SWMM model.

3. The method for detecting the biodegradation amount of BOD in sewage pipes based on SWMM according to claim 1 is characterized in that: The method for obtaining flow data, flow velocity data and liquid level data of a plurality of monitoring points includes: Arranging a flow meter in the inspection well, and using the flow meter to obtain the flow data and the flow velocity data; A liquid level meter is arranged in the inspection well, and the liquid level data is acquired by using the liquid level meter.

4. The method for detecting the biodegradation of BOD in sewage pipes based on SWMM according to claim 1, characterized in that: The method for obtaining the average wetted peripheral area of ​​each pipe segment comprises: Based on the liquid level data of each pipe segment and in combination with the pipe diameter data of each pipe segment, the dynamic wetted peripheral area of ​​each pipe segment is calculated; The average wetted peripheral area of ​​each of the pipe segments is calculated based on the dynamic wetted peripheral area of ​​each of the pipe segments.

5. The method for detecting the biodegradation of BOD in sewage pipes based on SWMM according to claim 1, characterized in that: The method for calculating the methane yield and the hydrogen sulfide yield includes: Selecting at least one of the pipe sections, and calculating the sampling intervals of the starting inspection well and the end inspection well of the pipe section based on the flow velocity data; Based on the sampling interval, collecting water samples from the starting inspection well and the end inspection well; Using high performance gas chromatography to detect the methane concentration and hydrogen sulfide concentration in the water sample, and calculating the difference in methane concentration and hydrogen sulfide concentration between upstream and downstream in the pipe section; Based on the flow data, the average wetted area, the methane concentration difference and the hydrogen sulfide concentration difference, the methane yield and the hydrogen sulfide yield are calculated: Wherein, x represents methane or hydrogen sulfide; P x Indicates the methane or hydrogen sulfide yield, g / m 2 / d; ΔC x Indicates the difference in methane concentration or hydrogen sulfide concentration, mg / l; Q indicates the flow rate data, l / s; W indicates the average wetted area, m 2 .

6. A method for detecting the biodegradation of BOD in sewage pipes based on SWMM according to claim 5, characterized in that: The method of selecting at least one of the pipe sections includes: selecting at least one sewage pipe with a distance of more than 100m and no branch pipe connected in the area to be detected; The method for determining whether the sewage pipe has a branch pipe connected thereto comprises: obtaining the starting flow data and the ending flow data of the sewage pipe, and when the starting flow data and the ending flow data are equal, determining that the sewage pipe has no branch pipe connected thereto.

7. The method for detecting the biodegradation of BOD in sewage pipes based on SWMM according to claim 1, characterized in that: The method for calculating the BOD biological degradation amount includes: Based on the average wetted area, the methane yield and the hydrogen sulfide yield of each pipe section, the methane yield and the hydrogen sulfide yield of each pipe section are calculated: MP x =P x IN Wherein, x represents methane or hydrogen sulfide; M x Indicates the methane or hydrogen sulfide production, g / d; P x Indicates the methane or hydrogen sulfide yield, g / m 2 / d; W represents the average wetted area, m 2 ; Adding the methane production of each pipe section to obtain the total methane volume of the sewage pipe; Adding the hydrogen sulfide production of each pipe section to obtain the total amount of hydrogen sulfide in the sewage pipe; Based on the total amount of methane and the total amount of hydrogen sulfide, the BOD biological degradation amount is calculated: in, represents methane production, g / d; Indicates hydrogen sulfide production, g / d; M BOD Indicates BOD production, g / d; n indicates the number of pipe sections.

8. A sewage pipe BOD biological degradation detection system based on SWMM, the detection system using the detection method according to any one of claims 1 to 7, characterized in that: include: Model building module, data monitoring module, wetted area calculation module, yield calculation module and degradation amount calculation module; The model building module is used to establish a sewage pipe network model of the area to be detected in the SWMM model; The data monitoring module is used to arrange a number of monitoring points in the inspection well of the sewage pipe in the area to be detected, and obtain flow data, flow velocity data and liquid level data of the monitoring points; The wetted area calculation module is used to input the flow data and the liquid level data into the sewage pipe network model to obtain the average wetted area of ​​each pipe section in the monitoring period; The yield calculation module is used to select at least one of the pipe sections, and obtain the methane yield and hydrogen sulfide yield of the pipe section based on the average wetted circumference area of ​​the pipe section; The degradation amount calculation module calculates the BOD biological degradation amount of the sewage pipe based on the methane yield, the hydrogen sulfide yield and the average wetted peripheral area of ​​each pipe section.

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