Urban non-point source pollution simulation analysis system and simulation analysis method

Abstract

This application provides a simulation analysis system and method for urban non-point source pollution. The simulation analysis system for urban non-point source pollution includes an underlying surface device, model pollutants, and a rainfall device. The underlying surface device has an adjustable slope simulated road surface with drainage outlets for discharging water samples flowing down from the simulated road surface. The model pollutants are distributed on the simulated road surface. The rainfall device is installed above the simulated road surface to simulate rainfall onto it. The adjustable slope of the underlying surface device simulates various road surface conditions, the rainfall device simulates various actual rainfall conditions, and the model pollutants simulate pollutants. This system can accurately obtain the pollution characteristics, causes, and formation mechanisms of rainfall runoff, solving the problem of the difficulty in accurately quantifying the pollution characteristics in urban rainfall runoff.

Description

Technical Field

[0001] This application belongs to the field of environmental pollution assessment technology, and more specifically, it relates to a simulation analysis system and simulation analysis method for urban non-point source pollution. Background Technology

[0002] Urban rainwater runoff pollution refers to the non-point source pollution of water bodies caused by rainwater and its runoff flowing over urban surfaces, allowing pollutants such as crude oil, nitrogen, phosphorus, heavy metals, and organic matter accumulated on the urban surface to directly enter water bodies through drainage systems. Urban rainwater runoff pollution is increasingly becoming a major cause of environmental problems such as eutrophication of urban water bodies, river siltation, and water quality deterioration. The severity of urban rainwater runoff pollution has gradually attracted widespread attention from researchers both domestically and internationally, leading to the development of related studies on the characteristics of urban rainwater runoff pollution.

[0003] Currently, research on urban rainfall runoff mechanisms is mainly based on field experimental data analysis. Considering the characteristics of urban topography, rainfall, climate, and land use, different underlying surfaces are selected, with roads and roofs being common examples. Using catchment areas as research units, changes in pollutant concentrations in rainfall runoff from different underlying surfaces are monitored, and the pollution characteristics of rainfall runoff from different underlying surfaces are analyzed. Based on this analysis, the pollution characteristics, causes, and formation mechanisms of urban rainfall runoff are investigated.

[0004] Field experiments involve numerous uncontrollable factors, resulting in poor reproducibility and an inability to accurately quantify the pollution characteristics and mechanisms of rainfall runoff. The main uncontrollable factors include:

[0005] Field experiments rely on natural rainfall, but the intensity and duration of rainfall are uncontrollable;

[0006] The accumulation of pollutants on different underlying surfaces varies significantly at different dry periods, resulting in large differences in pollutant concentrations in runoff after scouring.

[0007] The slope of the underlying surface cannot be adjusted; experiments can only be conducted on a selected slope, and analysis of multiple slopes is not possible. Summary of the Invention

[0008] Based on this, the purpose of this application is to provide a simulation analysis system for urban non-point source pollution, so as to solve the technical problems in the existing technology that there are many uncontrollable factors in field experiments, poor reproducibility of experiments, and inability to accurately quantify the pollution characteristics and mechanisms of rainfall runoff.

[0009] Another objective of this application is to provide a simulation analysis method for implementing a simulation analysis system for urban non-point source pollution.

[0010] To achieve the above-mentioned objectives, the technical solution of this application is as follows:

[0011] A simulation and analysis system for urban non-point source pollution, comprising:

[0012] The underlying surface device has a simulated road surface with an adjustable slope. The simulated road surface is equipped with a drain outlet for discharging water samples flowing down from the simulated road surface.

[0013] Model pollutants, model pollutant distribution on simulated road surface; and

[0014] A rain-simulating device is installed above a simulated road surface and is used to simulate rain onto the simulated road surface.

[0015] Optionally, the model pollutants include actual road sediments and pollution substitutes, with the actual road sediments being particulate and the mass ratio of actual road sediments to pollution substitutes being (80-88):(26-29).

[0016] Optionally, the actual road sediments include first sediments with a particle size of 0-250 μm and second sediments with a particle size of 250-500 μm, with a mass ratio of (2-5):1 for the first sediments and the second sediments.

[0017] And / or, alternative pollutants include at least one of potassium hydrogen phthalate particles, potassium nitrate particles, ammonium chloride particles, and potassium dihydrogen phosphate particles.

[0018] Optionally, the slope of the simulated road surface is 0°-30°;

[0019] And / or, the underlying surface device includes a surface body, with the simulated road surface located on the side of the surface body facing the rainfall device, and the simulated road surface being 2-3.5m long and 1-2m wide.

[0020] Optionally, the underlayment device includes a movable component, which is mounted on the underlayment body and is used to move the position of the underlayment body.

[0021] Optionally, the simulated road surface includes at least one of the following: waterproof roof surface, asphalt road surface, concrete road surface, permeable paving brick, dirt road surface and lawn.

[0022] Furthermore, a simulation analysis method is implemented using the aforementioned urban non-point source pollution simulation analysis system. The simulation analysis method includes the following steps:

[0023] The rainfall intensity was calibrated for the rainfall device;

[0024] A preset amount of model pollutants is placed on a simulated road surface, and a rainfall device is used to induce rainfall according to preset conditions.

[0025] Water samples were collected from the simulated road surface at the drainage outlet;

[0026] Detect and analyze pollution indicators in water samples.

[0027] Optionally, methods for calibrating rainfall intensity on rainfall devices include:

[0028] Set the height of the rain gauge to 17-19m, the rainfall intensity to 30mm / h-180mm / h, use 6-8 rain gauges to calibrate the rainfall intensity, the duration of the rainfall to 9-12min, remove the maximum and minimum values, calculate the mean value, and obtain the calibration value of the rainfall intensity.

[0029] Optionally, the preset conditions of the rainfall device include at least one of the following:

[0030] Rainfall patterns include at least one of the following: uniform, leading single peak, central single peak, late single peak, and bimodal.

[0031] Rainfall intensity varies between 5-40 mm / h and changes every 8-11 minutes.

[0032] Optionally, the water samples are collected according to the following pattern: once per minute within the first 10 minutes of rainfall, once every 5 minutes from the 10th to the 30th minute, and once every 15 minutes from the 30th to the 60th minute.

[0033] And / or, pollution indicators include the target concentrations of COD, total nitrogen, ammonia nitrogen, and total phosphorus.

[0034] The beneficial effects of this application are:

[0035] 1. The urban non-point source pollution simulation and analysis system provided in this application has an adjustable underlying surface device to simulate road surface slope for various road conditions, a rainfall device to simulate various actual rainfall conditions, and a model pollutant to simulate pollutants. It can accurately obtain the pollution characteristics, pollution causes, and formation mechanisms of rainfall runoff, solving the problem of difficulty in accurately quantifying pollution characteristics in urban rainfall runoff. Compared with the prior art, the urban non-point source pollution simulation and analysis system of this application can accurately measure the pollution characteristics, pollution causes, and formation mechanisms of rainfall runoff indoors, avoiding the problem of uncontrollable factors in field experiments, improving the reproducibility and accuracy of the experiment, and can simulate and analyze various rainfall pollution situations. It is also convenient to use.

[0036] 2. The simulation analysis method provided in this application has good controllability and reproducibility, which improves the accuracy of urban surface pollution analysis tests. Attached Figure Description

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0038] Figure 1 A schematic diagram of the structure of the urban non-point source pollution simulation and analysis system provided in the embodiments of this application;

[0039] Figure 2 for Figure 1 A schematic diagram of the surface matrix in a simulation analysis system for urban non-point source pollution;

[0040] Figure 3 (A) to Figure 3 (F) represent the simulated road surfaces in the urban non-point source pollution simulation analysis system of Embodiment 1 of this application: concrete pavement, asphalt pavement, roof waterproofing material, lawn, permeable brick pavement, and soil pavement;

[0041] Figure 4 The curve showing the change of COD in the water sample collected by the simulation analysis method in Example 1 over runoff time;

[0042] Figure 5 The curve showing the change of total nitrogen in water samples collected by the simulation analysis method in Example 1 over runoff time;

[0043] Figure 6 The curve showing the change of ammonia nitrogen in water samples collected by the simulation analysis method in Example 1 over runoff time;

[0044] Figure 7 The curve showing the change of total phosphorus in water samples collected by the simulation analysis method in Example 1 over runoff time;

[0045] Figure 8 The curve showing the change of suspended solids concentration over runoff time using the simulation analysis method in Example 1;

[0046] Figure 9 The curve showing the change of COD in water samples collected by the simulation analysis method in Example 2 as a function of runoff time;

[0047] Figure 10 The curve showing the change of total nitrogen in water samples over runoff time, collected using the simulation analysis method in Example 2;

[0048] Figure 11 The curve showing the change of ammonia nitrogen in water samples over runoff time, collected by the simulation analysis method in Example 2;

[0049] Figure 12 The curve showing the change of total phosphorus in water samples collected by the simulation analysis method in Example 2 over runoff time;

[0050] Figure 13 The curve showing the change of suspended solids concentration over runoff time in the simulation analysis method of Example 2;

[0051] Figure 14This is a graph showing the variation of rainfall intensity with rainfall duration for different rainfall types in Example 3;

[0052] Figure 15 The curve showing the change of COD in water samples collected by the simulation analysis method in Example 3 over runoff time;

[0053] Figure 16 The curve showing the change of total nitrogen in water samples collected by the simulation analysis method in Example 3 over runoff time;

[0054] Figure 17 The curve showing the change of ammonia nitrogen in water samples collected by the simulation analysis method in Example 3 over runoff time;

[0055] Figure 18 The curve showing the change of total phosphorus in water samples collected by the simulation analysis method in Example 3 over runoff time;

[0056] Figure 19 The curve showing the change of suspended solids concentration with runoff time is shown in Example 3, based on the simulation analysis method.

[0057] Explanation of icon numbers:

[0058] 1. A simulation and analysis system for urban non-point source pollution;

[0059] 10. Subsurface device; 11. Simulated road surface; 12. Drainage port; 13. Subsurface body; 14. Mounting frame; 15. Moving components;

[0060] 20. Rainfall device. Detailed Implementation

[0061] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0062] Please refer to the following: Figures 1 to 2 This application provides a simulation analysis system 1 for urban non-point source pollution, including an underlying surface device 10, model pollutants, and a rainfall device 20. The underlying surface device 10 has a simulated road surface 11 with an adjustable slope, and the simulated road surface 11 is provided with a drain outlet 12 for discharging water samples flowing down from the simulated road surface 11. Model pollutants are distributed on the simulated road surface 11. The rainfall device 20 is installed above the simulated road surface 11 and is used to simulate rainfall onto the simulated road surface 11.

[0063] The urban non-point source pollution simulation analysis system 1 provided in this application embodiment has an underlying surface device 10 that can adjust the slope of the simulated road surface 11 to simulate various road surface conditions, a rainfall device 20 that can simulate various actual rainfall conditions, and a model pollutant that can simulate pollutants. It can accurately obtain the pollution characteristics, pollution causes, and formation mechanisms of rainfall runoff, and solve the problem that it is difficult to accurately quantify the pollution characteristics in urban rainfall runoff.

[0064] Compared with the prior art, the urban non-point source pollution simulation analysis system 1 of this application embodiment can accurately measure the characteristics, causes and formation mechanisms of rainfall runoff pollution indoors, avoiding the problem of uncontrollable factors in field experiments, improving the reproducibility and accuracy of the experiment, and can simulate and analyze various rainfall pollution situations, and is easy to use.

[0065] In some embodiments, such as Figure 1 and Figure 2 As shown, the underlying surface device 10 includes a surface body 13, and a simulated road surface 11 is located on the side of the surface body 13 facing the rain-receiving device 20 to receive simulated rainwater falling from the rain-receiving device 20. It can be understood that the simulated road surface 11 and the surface body 13 can be an integral structure, that is, the simulated road surface 11 is one side of the surface body 13.

[0066] The simulated road surface 11 in this embodiment is used to simulate road surface conditions to obtain accurate rainfall runoff pollution characteristics, pollution causes, and formation mechanisms. Optionally, the simulated road surface includes at least one of the following: waterproof roof surface, asphalt road surface, concrete road surface, permeable paving bricks, dirt road surface, and lawn. For example, concrete road surface, asphalt road surface, waterproof roof surface, lawn, permeable paving bricks, and dirt road surface are respectively... Figure 3 A, B, C, D, E, and F in the simulation are all common road surfaces. The simulated road surface can be a single type or a combination of multiple road surfaces. For example, when the road surface to be studied is an asphalt road, the simulated road surface is an asphalt road; when the road surface to be studied is a concrete road with grass in between, the simulated road surface is a combination of concrete road surface and grass, and so on.

[0067] Understandably, depending on the needs of the research, simulated road surface 11 can also be other road surfaces besides waterproof roof surfaces, asphalt roads, concrete roads, permeable pavers, dirt roads, and lawns.

[0068] The preparation of the surface pad body 13 is also based on the road surface to be simulated. For example, when the simulated road surface 11 is an asphalt road surface, in some embodiments, the preparation method of the surface pad body 13 includes:

[0069] Lay a 25-28cm layer of soil at the bottom of the molding mold to form a soil layer;

[0070] Permeable bricks are laid on the upper surface of the soil layer to form a permeable brick layer;

[0071] Lay concrete on the top surface of the permeable brick layer and cure it for at least 10 days to prevent cracking and form a concrete layer.

[0072] After the concrete layer has been cured, use stone sealant to seal the gap between the concrete layer and the molding mold to prevent rainwater from seeping down along the gap;

[0073] Asphalt is laid on the upper surface of the concrete layer and dried to form an asphalt pavement, thus obtaining the main body of the subsurface 13.

[0074] In some embodiments, the slope θ of the simulated road surface 11 is 0°-30°. This road surface slope θ is a common road surface slope and can be used to simulate the pollution situation analysis of common road surface slopes. Researchers can also adjust it to be greater than 30° according to the road surface slope to be studied.

[0075] In this embodiment, the slope of the simulated road surface refers to the angle between the simulated road surface and the horizontal plane. For example... Figure 1 As shown, since the simulated road surface is parallel to the bottom surface of the main body of the pad, the slope of the simulated road surface and the angle between the bottom surface of the main body of the pad and the horizontal plane are equal.

[0076] In some embodiments, the length a of the simulated road surface 11 is 2-3.5m and the width b is 1-2m. This range of length a and width b can provide sufficient road surface area to study the pollution of rainfall runoff, analyze the causes and formation mechanisms of pollution, and avoid the situation where the length and width of the simulated road surface 11 are too large, occupying too much space, or the length and width are too large, resulting in the simulated rainwater flow time being too long, which reduces the efficiency of experimental analysis.

[0077] Optionally, the height h of the pad body 13 is 35-45cm. Here, the height h of the pad body 13 can be understood as the thickness. This thickness of the pad body is sufficient to pave various structural layers of the road and simulate an actual road.

[0078] Understandably, the drain outlet 12 is located at a low position on the simulated road surface 11. A slope generally includes a high position and a low position, with the elevation of the high position being greater than that of the low position. In this embodiment, the low position refers to a position with a smaller elevation. In some embodiments, the high and low positions are opposite sides of the simulated road surface 11, and the drain outlet 12 is located at the low position of the simulated road surface 11, on the side opposite the high position within the surface body 13. This facilitates the collection of water samples flowing down from the high position of the simulated road surface 11 for analysis of the pollution characteristics of the entire road section.

[0079] Optionally, the number of drainage outlets 12 is three, with at least one drainage outlet 12 used to collect water samples from infiltration runoff and at least one drainage outlet 12 used to collect water samples from surface runoff, in order to more comprehensively analyze the pollution situation and formation mechanism.

[0080] In some embodiments, the underlayment device 10 includes a mounting frame 14, one end of the underlayment body 13 is movably connected to the mounting frame 14, and this end of the underlayment body 13 can rise or fall linearly relative to the mounting frame 14 to adjust the slope of the simulated road surface 11.

[0081] Optionally, one end of the pad body 13 is movably connected to the mounting frame 14 via a suspension rope, or the mounting frame 14 is provided with a track, and one end of the pad body 13 is provided with a slider that matches the track at the position of the track. The slider can move up or down along the track, and the height of one end of the pad body is adjusted by the movement of the slider relative to the track, thereby adjusting the slope of the simulated road surface 11.

[0082] In some embodiments, the mounting frame 14 includes a lifting rod, which includes a fixed section and a telescopic section. One end of the telescopic section is movably connected to the fixed section, and the other end of the telescopic section is fixedly connected to one end of the pad body 13. The telescopic section can move relative to the fixed section. In some embodiments, this relative movement is manifested as the telescopic section extending or shortening relative to the fixed section. The slope of the simulated road surface 11 is adjusted by the relative movement of the telescopic section to the fixed section.

[0083] In some embodiments, such as Figure 1 As shown, the underlayment device 10 includes a moving component 15, which is mounted on the underlayment body 13. The moving component 15 is used to move the position of the underlayment body 13 so as to transport the underlayment body 13 to a suitable location for testing. Optionally, the moving component 13 includes multiple rollers. The rollers are easy to slide, have low resistance, and are easy to move.

[0084] In some embodiments, the model pollutants include actual road sediments and pollution substitutes. Actual road sediments are sediments obtained from roads, such as stones and gravel, and are granular with a particle size of 0-500 μm. Based on investigations, 0-10% of actual road sediment pollutants may be covered by objects such as plastics and paper, while over 90% are uncovered and exposed on the road surface. During rainfall, they are carried away by rainwater along with other pollutants, and their particle size is between 0-500 μm. Therefore, the embodiments of this application use granular actual road sediments, which basically conform to the pollutant conditions of road surfaces.

[0085] In some embodiments, the actual road sediments include a first sediment with a particle size of 0-250 μm and a second sediment with a particle size of 250-500 μm. Depending on the research, the first and second sediments are mixed in a certain ratio, for example (2-5):1. The monthly load, weekly load and daily load can be measured by changing the amount of model pollutants added.

[0086] Optionally, the pollutant substitutes include at least one of potassium hydrogen phthalate, potassium nitrate, ammonium chloride, and potassium dihydrogen phosphate, which respectively replace pollutants such as COD, total nitrogen, ammonia nitrogen, and total phosphorus. Depending on the experimental requirements, one or a combination of multiple pollutant substitutes may be selected.

[0087] In some embodiments, the pollution substitutes include potassium hydrogen phthalate, potassium nitrate, ammonium chloride and potassium dihydrogen phosphate, wherein the mass ratio of potassium hydrogen phthalate, potassium nitrate, ammonium chloride and potassium dihydrogen phosphate is (0.9-1.5):(1-1.5):(7.5-9):(70-80).

[0088] In some embodiments, the mass ratio of actual road deposits to pollutant substitutes is (80-88):(26-29), which is consistent with the proportion of road deposits and pollutants in most actual roads. Understandably, the mass ratio of actual road deposits to pollutant substitutes can also be adjusted according to actual road surface conditions.

[0089] This application embodiment also provides a simulation analysis method, implemented using the above-mentioned urban non-point source pollution simulation analysis system 1, which includes the following steps:

[0090] S01: Perform simulated rainfall intensity calibration on the rainfall device 20.

[0091] The rainfall intensity of the rainfall device 20 is calibrated to obtain an accurate rainfall intensity.

[0092] Optionally, the method for calibrating the rainfall intensity of the rainfall device 20 includes:

[0093] The height of the rainfall device 20 is set to 17-19m, the rainfall intensity is set to 30mm / h-180mm / h, 6-8 rain gauges are used to calibrate the rainfall intensity, the duration of rainfall is 9-12min, the maximum and minimum values ​​are removed, the mean value is calculated, and the calibration value of the rainfall intensity is obtained.

[0094] S02: Place a preset amount of model pollutants on the simulated road surface 11, and use a rainfall device to generate rainfall according to preset conditions.

[0095] Place a preset amount of model pollutants to simulate real pollutants.

[0096] Optionally, the preset conditions of the rainfall device 20 include at least one of the following:

[0097] Rainfall patterns include at least one of the following: uniform, leading single peak, central single peak, late single peak, and bimodal.

[0098] Rainfall intensity varies between 5-40 mm / h and changes every 8-11 minutes.

[0099] The appropriate rainfall type and intensity can be selected based on the research situation; it can be a single rainfall type or a combination of multiple rainfall types. Regarding rainfall intensity, since actual rainfall events can involve various variations in intensity, the experiment can select one rainfall intensity or a combination of multiple rainfall intensities as needed.

[0100] S03: Collect water samples flowing down from the simulated road surface at drain outlet 12.

[0101] Optionally, the water samples are collected according to the following pattern: once per minute within the first 10 minutes of rainfall, once every 5 minutes from the 10th to the 30th minute, and once every 15 minutes from the 30th to the 60th minute.

[0102] S04: Detect and analyze pollution indicators in water samples.

[0103] In some embodiments, the pollution indicators of the water sample include the pollution concentrations of target COD, total nitrogen, ammonia nitrogen, and total phosphorus, i.e., the concentrations of these pollutants in the water sample.

[0104] The simulation analysis method provided in this application has good controllability and reproducibility, which improves the accuracy of urban surface pollution analysis tests.

[0105] The following examples illustrate this.

[0106] Example 1

[0107] This embodiment simulates the impact of different underlying surface types on the migration patterns of pollution from rainfall runoff.

[0108] The urban non-point source pollution simulation and analysis system of this embodiment includes an underlying surface device, model pollutants, and a rainfall device.

[0109] The subsurface device includes a subsurface body, a mounting frame, and a moving assembly. The subsurface body is a cuboid 3m long, 1.5m wide, and 40cm high. Three drainage ports, each 2cm in diameter, are located at the bottom of the subsurface body. The mounting frame is movably connected to one end of the subsurface body. The moving assembly, consisting of four rollers, is mounted on the bottom of the subsurface body.

[0110] The surface of the main body of the pad has a simulated road surface, and the lower pad device is equipped with a drain outlet, which is connected to the simulated road surface and is used to discharge water samples flowing down from the simulated road surface.

[0111] The model pollutants consist of road particulate matter ranging from 0 to 500 μm, as well as compounds such as potassium hydrogen phthalate, potassium nitrate, ammonium chloride, and potassium dihydrogen phosphate. The model pollutants are evenly distributed on the simulated road surface.

[0112] The rain-generating device is installed above the simulated road surface and is used to generate rainfall.

[0113] The preparation method of the underlayment device includes:

[0114] Lay a 25cm thick layer of soil into the molding mold and compact it to form a soil layer;

[0115] A layer of permeable bricks, 3cm thick, is laid on the surface of the soil layer to form a permeable brick layer;

[0116] The C30 concrete, sand, stone, and water are mixed in a ratio of 1:1.4:2.8:0.48 and stirred evenly to obtain the concrete.

[0117] Concrete is laid on the surface of the permeable brick layer to form a concrete layer with a thickness of 2cm;

[0118] The concrete layer is cured for 12 days. During the curing process, water is sprayed onto the surface of the concrete layer. Specifically, water is sprayed 3 times a day from day 0 to 5, and once a day from day 6 to 12.

[0119] After the concrete underlayment test was completed, the simulated road surface was replaced with asphalt road surface, roof waterproofing material, lawn, permeable brick road surface, and soil road surface to study the impact of different simulated road surfaces on the migration pattern of pollutants in rainfall runoff.

[0120] The rain-making device is installed at a height of 18m above the ground.

[0121] The simulation analysis method in this embodiment includes the following steps:

[0122] S01: The rainfall intensity is calibrated for the rainfall device. The required rainfall intensity in the test is 10 mm / h. During the calibration, the rainfall duration is 10 min. The maximum and minimum values ​​are removed, and the mean of the remaining values ​​is calculated. This mean is the calibration rainfall intensity. The test is repeated 3 times. After the error is less than 20%, the corresponding pressure and the opening degree of the rainfall device can be determined.

[0123] S02: The dosage of simulated pollutants is determined based on the different levels of underlying surface pollution in the target city. The simulated pollutants are obtained by mixing pollutant substitutes and actual road sediments. The pollutant substitutes include potassium hydrogen phthalate, potassium nitrate, ammonium chloride, and potassium dihydrogen phosphate. The actual road sediments are divided into first and second sediments based on particle size. The first sediment has a particle size of 0-250 μm, and the second sediment has a particle size of 250-500 μm, with a mass ratio of 3:1. The mass ratios of potassium hydrogen phthalate, potassium nitrate, ammonium chloride, and potassium dihydrogen phosphate in the pollutant substitutes to the first and second sediments are shown in Table 1. After mixing the pollutant substitutes with the actual road sediments, the mixture is added to the simulated underlying surface.

[0124] Table 1

[0125] First sediment Second sediment Potassium hydrogen phthalate 1.04 0.35 potassium nitrate 1.10 0.37 ammonium chloride 8.33 2.78 Potassium dihydrogen phosphate 74.53 24.84

[0126] S03: Set the rainfall intensity of the rainfall device to 10 mm / h, the slope of the simulated road surface to 5°, and carry out a rainfall test. Record the time of runoff generation as 0 min, and set the sampling time to 0, 1, 2, 3, 4, 5, 7, 10, 15, 30, 45 and 60 min respectively, with 12 sampling time points set for each group.

[0127] S04: Analyze and measure the suspended solids concentration, COD, total nitrogen, ammonia nitrogen, and total phosphorus in water samples, and plot the changes in these indicators over runoff time. Figures 4 to 8 As shown.

[0128] Figures 4 to 8 In the graph, the vertical axis represents the concentration of various pollutants, and the horizontal axis represents the runoff duration. Due to the initial flushing effect, the pollutant concentration in the runoff is relatively high in the first 5 minutes after rainfall. Therefore, in addition to the suspended solids concentration, the four indicators of COD, total nitrogen, ammonia nitrogen, and total phosphorus need to be diluted during the test; the water sample between 7 and 60 minutes does not need to be diluted.

[0129] Example 2

[0130] This embodiment simulates the impact of different simulated road surface slopes on the migration patterns of rainwater runoff pollution.

[0131] The simulation analysis system, preparation method of the underlying surface device, and simulation analysis method for urban non-point source pollution in this embodiment are largely the same as those in Embodiment 1. The simulated road surface is a concrete road surface. The difference lies in:

[0132] In step S04, the slope during rainfall is changed, and the slope of the simulated road surface is adjusted to 5°, 10°, 15°, and 20° respectively.

[0133] Figures 9 to 13 The figures show the changes in the concentrations of COD, total nitrogen, ammonia nitrogen, total phosphorus, and suspended solids in water samples over runoff time under various slope conditions of the simulated road surface. The vertical axis represents the concentration of various pollutants, and the horizontal axis represents the runoff duration. Due to the initial scouring effect, the pollutant concentration in the runoff is relatively high in the first 5 minutes after rainfall. Therefore, in addition to the suspended solids concentration, the four indicators of COD, total nitrogen, ammonia nitrogen, and total phosphorus need to be diluted during the test. Water samples taken between 7 and 60 minutes do not need to be diluted.

[0134] Example 3

[0135] This embodiment simulates the impact of different rainfall patterns on the migration patterns of pollution in rainfall runoff.

[0136] The simulation analysis system, preparation method of the underlying surface device, and simulation analysis method for urban non-point source pollution in this embodiment are largely the same as those in Embodiment 1. The simulated road surface is a concrete road surface with a slope of 5°. The difference lies in:

[0137] In step S04, the rainfall pattern during the experiment was changed to four types: uniform, front-peak, mid-peak, and rear-peak. The changes in rainfall intensity with rainfall duration are as follows: Figure 14 As shown.

[0138] Figures 15 to 19 The graphs show the changes in the concentrations of COD, total nitrogen, ammonia nitrogen, total phosphorus, and suspended solids in water samples over runoff time under various rainfall patterns. The vertical axis represents the concentration of each pollutant, and the horizontal axis represents the runoff duration. Due to the initial flushing effect, the pollutant concentration in the runoff is relatively high in the first 5 minutes of rainfall. Therefore, except for the suspended solids concentration, the concentrations of COD, total nitrogen, ammonia nitrogen, and total phosphorus need to be diluted during testing. Water samples taken between 7 and 60 minutes do not require dilution.

[0139] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A simulation and analysis system for urban non-point source pollution, characterized in that: include: The underlying surface device has a simulated road surface with an adjustable slope, and the simulated road surface is provided with a drain outlet for discharging water samples flowing down from the simulated road surface. Model pollutants, which are distributed on the simulated road surface; as well as A rain-simulating device is installed above the simulated road surface and is used to simulate rain onto the simulated road surface. The model pollutants include actual road deposits and pollution substitutes, with the mass ratio of actual road deposits to pollution substitutes being (80-88):(26-29). The actual road sediments include a first sediment with a particle size of 0-250 μm and a second sediment with a particle size of 250-500 μm, and the mass ratio of the first sediment to the second sediment is (2-5):1; The pollution substitute is selected from at least one of potassium hydrogen phthalate granules, potassium nitrate granules, ammonium chloride granules and potassium dihydrogen phosphate granules. The underlying surface device includes a surface body and a mounting frame, with the simulated road surface located on the side of the surface body facing the rainfall device; One end of the pad body is movably connected to the mounting frame via a suspension rope; or, the mounting frame is provided with a track, and one end of the pad body is provided with a slider that matches the track, the slider being able to move up or down along the track; or, the mounting frame includes a lifting rod, the lifting rod including a fixed section and a telescopic section, one end of the telescopic section being movably connected to the fixed section, the other end of the telescopic section being fixedly connected to one end of the pad body, the telescopic section being able to extend or shorten relative to the fixed section.

2. The simulation and analysis system for urban non-point source pollution as described in claim 1, characterized in that: The slope of the simulated road surface is 0°-30°; And / or, the simulated road surface is 2-3.5m long and 1-2m wide.

3. The simulation and analysis system for urban non-point source pollution as described in claim 1, characterized in that: The underlayment device includes a movable component, which is mounted on the underlayment body and is used to move the position of the underlayment body.

4. The simulation and analysis system for urban non-point source pollution as described in claim 1, characterized in that: The simulated road surface is selected from at least one of the following: waterproof roof surface, asphalt road surface, concrete road surface, permeable paving brick, soil road surface and lawn.

5. A simulation analysis method, characterized in that: The implementation using the urban non-point source pollution simulation analysis system according to any one of claims 1 to 4 includes the following steps: The rainfall device was calibrated using simulated rainfall intensity. A preset amount of the model pollutants is placed on the simulated road surface, and the rainfall device is used to induce rainfall according to preset conditions. Water samples flowing down the simulated road surface are collected at the drainage outlet; The pollution indicators of the water sample were detected and analyzed.

6. The simulation analysis method as described in claim 5, characterized in that: The method for calibrating the rainfall intensity of the rainfall device includes: The height of the rainfall device is set to 17-19m, the rainfall intensity is set to 30 mm / h-180 mm / h, 6-8 rain gauges are used to calibrate the rainfall intensity, the duration of rainfall is 9-12min, the maximum and minimum values ​​are removed, the mean value is calculated, and the calibration value of the rainfall intensity is obtained.

7. The simulation analysis method as described in claim 5 or 6, characterized in that: The preset conditions of the rainfall device include at least one of the following: Rainfall patterns include at least one of the following: uniform, leading single peak, central single peak, late single peak, and bimodal. Rainfall intensity varies between 5-40 mm / h and changes every 8-11 minutes.

8. The simulation analysis method as described in claim 7, characterized in that: The water samples were collected according to the following pattern: once per minute during the first 10 minutes of rainfall, once every 5 minutes during the 10th to 30th minute, and once every 15 minutes during the 30th to 60th minute. And / or, the pollution indicators include the pollution concentrations of target COD, total nitrogen, ammonia nitrogen, and total phosphorus.

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