Urban initial rainwater intelligent collection system and method

Abstract

An urban initial rainwater intelligent collection system and a method. According to the system, the pollutant concentration process and peak value of rainwater in the initial state of rainfall are predicted by means of an urban rainfall runoff pollution transmission model, an initial rainwater collection duration is determined by means of an initial rainwater collection method, and initial rainwater is collected by using initial rainwater collection devices, so as to achieve intelligent collection of the initial rainwater. For a built rainwater pipe network, only rainwater collection ports need to be modified, each initial rainwater collection device is connected to devices such as a rainwater port and a municipal sewage pipe in the municipal pipe network, newly-built rainwater pipe network supporting construction is carried out, and the present invention has the advantages of low cost, easy maintenance, good adaptability and high pollution collection efficiency.

Description

An intelligent urban initial rainwater collection system and method Technical Field

[0001] The present invention relates to the technical field of initial rainwater pollution control, and in particular to an intelligent urban initial rainwater collection system and method. Technical Background

[0002] Primary rainwater, which forms runoff and is highly polluted in the early stages of rainfall, is a significant component of urban non-point source pollution. Once primary rainwater forms runoff, it washes over urban roads, buildings, and waste, transporting pollutants accumulated on the urban surface to receiving water bodies. This leads to deterioration of urban water bodies and ecological damage. Its prevention and control is a key shortcoming in the current battle against urban water pollution.

[0003] Numerous factors influence initial stormwater pollution. Rainfall timing, intensity, and underlying surface conditions all influence the initial stormwater runoff process and pollution concentrations, making it difficult to predict and manage. Therefore, scientifically assessing the initial stormwater runoff process, pollution peaks, and duration, and effectively intercepting highly polluted water bodies, are key to controlling initial stormwater.

[0004] The control of initial rainwater is mainly divided into source control, process control and terminal control.

[0005] Source control involves increasing the permeability of urban surfaces to retain rainwater and pollution in situ for controlled purification. Initial rainwater pollution can be controlled and purified in situ through methods such as laying permeable blankets and establishing artificial wetlands. However, this method is costly and requires significant land, making it unsuitable for use in most Chinese cities.

[0006] Process control refers to the control of initial runoff from surface runoff to its flow through stormwater pipes. Common process control methods include volumetric and flow-off methods. The volumetric method collects initial runoff through devices such as interception wells. Once the wells are full, the water overflows into the stormwater pipes and is discharged into the receiving water body. However, since the volume of the interception wells is often set based on experience, this method is relatively crude and ineffective in effectively capturing initial runoff. The flow-off method installs devices such as overflow wells in the middle of the stormwater pipes, with a flow-off pipe at the bottom connected to the sewage pipe. When rainfall begins, rainwater flowing through the device is initially discharged into the sewage pipe. When the rate of accumulation of rainwater in the device exceeds the rate of discharge, the device gradually fills and overflows into the stormwater pipes, discharging into the receiving water body. However, during rainfall, the flow-off pipes remain in a continuous flow-off state, making it difficult to quantitatively control the flow rate and placing a significant impact on the water volume of the sewage treatment plant, resulting in unstable pollution control results.

[0007] End-of-pipe control involves constructing rainwater storage ponds at the outlets of stormwater inlets to collect rainwater. After biochemical treatment to ensure that the water quality meets discharge standards, the clean rainwater is discharged into receiving water bodies. Larger storage ponds require larger capacity and floor space, increasing construction and operating costs. This makes them unsuitable for cities with limited land and poor economic development.

[0008] Existing initial rainwater control technologies have problems such as large land area, high cost, extensive methods, and low sewage interception efficiency. There is an urgent need to design an intelligent urban initial rainwater collection system. Through a pollutant transmission model based on physical mechanisms, the peak pollution level of initial rainwater can be determined, the initial rainwater collection time can be determined, and a small, low-cost, and high-efficiency collection device can be designed to achieve refined and intelligent collection of initial rainwater.

[0009] Summary of the Invention

[0010] Purpose of the invention: In response to the above technical problems, the present invention proposes an intelligent collection system and method for urban initial rainwater. An urban rainfall runoff pollution prediction model is used to accurately determine the pollution peak of initial rainwater. An urban initial rainwater collection method is used to determine the initial rainwater collection time. Initial rainwater is collected by an initial rainwater collection device, thereby realizing intelligent collection of initial rainwater and preventing highly polluted runoff from entering the receiving water body. The initial rainwater collection device is connected to rainwater outlets, municipal sewage pipes and other devices in the municipal pipe network to support the construction of a newly built rainwater pipe network. It has the advantages of low cost, easy maintenance, good adaptability and high pollution collection efficiency.

[0011] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0012] An urban initial rainwater intelligent collection system includes a rainfall monitoring module, an initial rainwater collection device and a control module, wherein:

[0013] The rainfall monitoring module is deployed at typical sampling points in the urban area to monitor rainfall amount and rainfall intensity, and transmits rainfall amount and rainfall intensity information to the control module;

[0014] The initial rainwater collection device is located at the rainwater inlet to collect initial rainwater pollution, and includes:

[0015] An initial rainwater pollution collection box, a control valve, a water level gauge, and an initial rainwater pumping and drainage system, wherein the initial rainwater pollution collection box is located at the water inlet of the rainwater pipe of the rainwater outlet, and a control valve is provided at the water inlet of the rainwater pipe to control rainwater from entering the initial rainwater pollution collection box through the control valve. A water level gauge is provided in the initial rainwater pollution collection box to monitor the amount of initial rainwater collected in the initial rainwater pollution collection box;

[0016] The initial rainwater pumping and drainage system is located at the bottom of the initial rainwater pollution collection box;

[0017] The control module is pre-installed with a rainfall runoff pollution prediction module. The rainfall runoff pollution prediction module can determine the collection time of the initial rainwater collection device through the rainfall and rainfall intensity information fed back by the rainfall monitoring module. By controlling the control valve and the initial rainwater pumping and drainage system in the initial rainwater collection device, the intelligent collection of initial rainwater is achieved to prevent highly polluted runoff from entering the receiving water body.

[0018] The rainfall runoff pollution prediction module provides pollutant source terms for the pollutant transport model by constructing a sunny day pollutant accumulation model, provides hydrodynamic calculation conditions for the pollutant transport model by constructing a hydrodynamic model, and predicts the pollutant transport process through a pollutant transport model based on physical reality.

[0019] For urban surface dissolved pollutants:

[0020] Where H is the water depth;

[0021] U is the flow velocity in the x direction; V is the flow velocity in the y direction; x and y are two perpendicular directions in the plane, x is along the direction of water flow, and y is the direction perpendicular to the water flow;

[0022] C is the average pollutant concentration along the water depth;

[0023] t is time;

[0024] D xx 、D xy 、D yx and D yy is the diffusion coefficient tensor, whose main direction is consistent with the direction of water flow;

[0025] S is the source term, which represents the amount of pollutants flowing into or out of the water body per unit area on the slope per unit time;

[0026] H C To control the thickness of the water layer;

[0027] C C is the concentration of dissolved pollutants.

[0028] For urban surface particulate pollutants:

[0029] Where c is the TSS concentration, mass per unit volume; m is the amount of sediment deposited per unit area; e r is the rate of sediment stripping under the action of raindrop splashing; r ris the sediment stripping rate under the action of runoff shear; h is the water layer thickness, q is the slope flow; d is the amount of surface sediment deposition; t is time.

[0030] The pollutant concentration output by the model is compared with the emission standard. When the pollutant concentration is continuously lower than the emission standard, the collection of initial rainwater is stopped, which determines the collection time of the initial rainwater collection device.

[0031] The typical sampling points in the urban area are measurement points in residential areas, commercial areas, industrial parks, roads and vegetation green areas that can clearly show the land use type, including a certain point on the main traffic artery as a typical measurement point for the road, and a certain point in a residential area with relatively intensive human activities as a typical measurement point for the residential area.

[0032] The rainfall monitoring module is a rainfall sensor.

[0033] The initial rainwater drainage system includes sewage pipes or water pumps, which are selected according to the layout of the municipal sewage network.

[0034] If the sewage pipe network passes through the initial rainwater pollution collection box within 3m, the sewage is discharged into the sewage pipe network through the sewage pipe;

[0035] If there is no sewage pipe network near the initial rainwater pollution collection box, a water pump will be installed at the bottom of the collection box to pump the water to the sewage collection vehicle for treatment and utilization on sunny days.

[0036] The present invention further discloses a method for collecting urban initial rainwater, based on the urban initial rainwater intelligent collection system, comprising the following steps:

[0037] (1) Basic data exploration and input: Conduct a basic survey of the topography, underlying surface conditions, and pipe network conditions in the selected urban area to clarify the sub-catchment division, number of rainwater inlets, distribution of different underlying surfaces, and road surface slope conditions in the area; conduct a survey of the water quality in the selected urban area to identify the typical pollutants in the area and select one or more typical pollutants as monitoring targets; conduct a survey of the maximum pollutant accumulation in the selected urban area, monitor the number of sunny days in the area, establish a sunny day pollutant accumulation model using a power exponential function model, and form a surface pollutant distribution dataset;

[0038] (2) After the urban initial rainwater intelligent collection system is built, it is set to the dry flow water inflow state. In this state, the rainfall runoff pollution prediction module is in a dormant state; the control valve is opened, the initial rainwater pumping system is closed, and the sewage flushed into the rainwater pipe on a sunny day will flow directly into the initial rainwater pollution collection box;

[0039] (3) The rainfall monitoring module monitors the rainfall process and transmits it to the rainfall runoff pollution prediction module in the controller. The rainfall runoff pollution prediction module simulates and predicts the rainwater runoff pollution based on the rainfall process and the surface pollutant distribution data. The urban initial rainwater intelligent collection system is set to the rainfall inflow mode, and the rainfall runoff pollution prediction module enters the working state; the corresponding state of the initial rainwater pollution collection box is still the dry flow inflow state, that is, the control valve is open and the initial rainwater pumping system is closed; after the runoff begins, the initial rainwater intelligent collection system starts to collect the initial rainwater;

[0040] (4) During the rainfall runoff process, the pollution peak is predicted by the rainfall runoff pollution prediction module. When the predicted rainwater concentration reaches the peak and then decreases, and the rainwater quality reaches the fifth category water quality standard for surface water, the rainfall runoff pollution prediction module continues to monitor for five prediction steps. If the runoff concentration has no growth trend, the control valve is closed, that is, the control valve and the initial rainwater pumping and drainage system are both in a closed state, and the clean rainwater enters the rainwater inlet and flows through the rainwater pipe directly into the receiving water body;

[0041] (5) During the rainfall runoff process, the initial rainwater in the initial rainwater pollution collection box is monitored by the water level gauge in the initial rainwater collection device. When the initial rainwater pollution collection box is full of rainwater, the control valve and the initial rainwater pumping and drainage system are both in a closed state, and the subsequent rainwater is directly discharged into the receiving water body;

[0042] (6) After the rainfall is over, the sewage in the initial rainwater collection device is discharged through the initial rainwater pumping system. After the discharge is completed, the system is set to the dry flow water inlet state again, that is, the control valve is opened, the initial rainwater pumping system is closed, and wait for the next rainfall. Beneficial effects:

[0043] The rainfall monitoring module and the initial rainwater collection device of the present invention are made of materials that are easy to obtain and construct. The initial rainwater collection device only requires the modification of the existing rainwater inlet or the construction of a new rainwater pipe network. At the same time, the initial rainwater collection system can flexibly and automatically intercept severely polluted initial rainwater, and has the advantages of less space occupation, easy maintenance, good adaptability, and high pollution collection efficiency.

[0044] The intelligent collection method for initial rainwater from urban rainfall runoff adopted in the present invention adopts a pollutant transmission model based on physical reality, and changes the empirical coefficients in the traditional model into coefficients with physical significance. The revised transmission model requires fewer parameters and less computing resources; it can accurately predict the pollution peak of initial rainwater from rainfall runoff in urban areas and collect the initial rainwater, and has the advantages of fast calculation speed, low energy consumption and accurate prediction. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a schematic structural diagram of an intelligent urban initial rainwater collection system according to the present invention;

[0046] Among them, there are a rainfall monitoring module 1, a rainfall runoff pollution prediction module 2, an initial rainwater pumping and drainage system 31, an initial rainwater collection device 32, a water level gauge 321, an initial rainwater collection box 322, a water pump and sewage pipe 323, a collection device connecting pipe 33, a rainwater inlet 34, a rainwater pipe branch 35, a control valve 36, and a rainwater pipe main pipe 37;

[0047] FIG2 is a cross-sectional view of an initial rainwater collection device according to the present invention;

[0048] FIG3 is a front view of a rainfall monitoring module according to the present invention;

[0049] Among them, the rain sensor 11, the controller 12, and the solar panel 13;

[0050] FIG4 is a side view of FIG3;

[0051] FIG5 is a decision flow chart of the present invention;

[0052] FIG6 is a schematic diagram of the initial state of the rainwater collection device of the present invention;

[0053] FIG7 is a second schematic diagram of the initial state of the rainwater collection device of the present invention;

[0054] FIG8 is a schematic diagram of drainage of the initial rainwater pumping and drainage system of the initial rainwater collection device of the present invention.

[0055] Specific implementation methods

[0056] To make the purpose and technical solutions of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the described 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.

[0057] The intelligent system for collecting initial rainwater from urban rainfall runoff, described in the present invention, includes a rainfall monitoring module, a rainfall runoff pollution prediction module, and an initial rainwater collection device. The rainfall monitoring module is deployed at typical sampling points within the urban area to monitor rainfall volume and intensity. The rainfall runoff pollution prediction module is built into the system and uses data transmitted by the rainfall monitoring module to predict initial rainwater pollution. The initial rainwater collection device is located at the rainwater inlet to collect the initial rainwater pollution.

[0058] The rainfall monitoring module of the present invention is arranged at typical sampling points in urban areas. Typical sampling points in urban areas include residential areas, commercial areas, industrial parks, roads, and vegetation green areas where the land use type can be clearly represented. For example, a certain point on a main traffic artery is selected as a typical road measurement point, and a certain point in a residential area with relatively dense human activities is selected as a typical residential measurement point.

[0059] The rainfall monitoring module is mainly a rainfall sensor, which monitors the rainfall process after the rainfall begins and transmits data to the rainfall runoff pollution prediction module.

[0060] The rainfall runoff pollution prediction module described in the present invention provides pollutant source terms for the pollutant transmission model by constructing a sunny day pollutant accumulation model, provides hydrodynamic calculation conditions for the pollutant transmission model by constructing a hydrodynamic model, and predicts the pollutant transmission process through a pollutant transmission model based on physical reality.

[0061] Based on the measured data, sunny-day accumulation process lines of various pollutants in the region are drawn and a sunny-day pollutant accumulation model is established. The model uses a power exponential model to predict sunny-day pollutant accumulation:

[0062] Among them, P t is the accumulated amount of pollutants in the catchment area t days after the last rainfall; P s is the initial pollution load in the catchment after a rainfall event; P m is the maximum accumulative amount of pollutants in the catchment area; k1 is the accumulation coefficient, which is related to factors such as local cleaning frequency, underlying surface type, and catchment area environment.

[0063] The sunny day pollutant accumulation model can predict the initial pollution load on the surface of urban areas before rainfall, and provide source terms for the pollutant transport model to calculate.

[0064] In the early stage of the watershed survey, the local cleaning frequency, underlying surface type, watershed environment and other conditions within the watershed corresponding to each initial rainwater collection device are determined. After determining the accumulation coefficient and the maximum accumulative pollutant accumulation, it is only necessary to determine the initial pollution load after the rain and the cumulative number of effective sunny days to determine the sunny day pollutant accumulation.

[0065] The prediction module estimates the accumulation of each pollutant in the area based on the number of sunny days and forms a surface pollutant distribution dataset.

[0066] The rainfall runoff pollution prediction module uses a two-dimensional shallow water equation to establish a hydrodynamic model to predict urban impervious road surface flow. The two-dimensional shallow water equation ignores evaporation and infiltration and considers rainfall:

[0067] Where η is the free water surface elevation; t is time; U and V are the velocity in the x-axis and the velocity in the y-axis, respectively; I is the rainfall intensity; H is the water depth, in meters; g is the acceleration due to gravity; and n is the Manning roughness coefficient.

[0068] The hydrodynamic model predicts the rainfall runoff process in urban areas through rainfall intensity and urban surface parameters, providing hydrodynamic calculation conditions for subsequent pollutant transport models.

[0069] The rainfall runoff pollution prediction module predicts the pollutant transmission process through a pollutant transmission model based on physical reality.

[0070] For urban surface dissolved pollutants:

[0071] Where H is the water depth;

[0072] U is the flow velocity in the x direction; V is the flow velocity in the y direction; x and y are two perpendicular directions in the plane, x is along the direction of water flow, and y is the direction perpendicular to the water flow;

[0073] C is the average pollutant concentration along the water depth;

[0074] t is time;

[0075] D xx 、D xy 、D yx and D yy is the diffusion coefficient tensor, whose main direction is consistent with the direction of water flow;

[0076] S is the source term, which represents the amount of pollutants flowing into or out of the water body per unit area on the slope per unit time;

[0077] H C To control the thickness of the water layer;

[0078] C C is the concentration of dissolved pollutants.

[0079] For urban surface particulate pollutants:

[0080] Where c is the TSS concentration, mass per unit volume; m is the amount of sediment deposited per unit area; e r is the rate of sediment stripping under the action of raindrop splashing; r r is the rate of sediment stripping under runoff shear; h is the water layer thickness; q is the slope flow rate; d is the amount of surface sediment deposited; and t is time. The pollutant transport model ultimately outputs the evolution of pollutant concentrations in the runoff.

[0081] The pollutant concentration results output by the model are compared with the emission standards. By comparing the predicted pollutant concentration with the concentration indicators of the emission standards, when the predicted pollutant concentration is lower than the dischargeable concentration standard, continue to monitor for five prediction steps (five predictions). If there is no increasing trend in the pollutant concentration, stop collecting initial rainwater, and thus achieve the effect of deciding the collection time of the initial rainwater collection device.

[0082] The initial rainwater collection device includes an initial rainwater pollution collection box, a control valve, a water level gauge and a sewage pipe;

[0083] The initial rainwater pollution collection box is located at the water inlet of the rainwater inlet, and the rainwater is controlled to enter the initial rainwater pollution collection device through the control valve. A water level meter is set in the collection box to monitor the amount of collected initial rainwater;

[0084] The volume of the initial rainwater pollution collection box is obtained through optimal calculation of different rainfall processes, regional initial pollution load and available floor area to ensure that the initial rainwater pollution collection box can collect all the pollution peaks.

[0085] The sewage pipe is located at the bottom of the initial rainwater pollution collection box. A water pump is provided on the sewage pipe. The selection is made according to the layout of the municipal sewage network. If the sewage network passes near the collection box along the way, a sewage drainage pipe can be installed in the initial rainwater pollution collection box to connect to the municipal sewage pipe.

[0086] After the rain stops, the sewage in the collection box is discharged into the sewage network through the sewage pipe; if there is no sewage network near the collection box, a water pump system is installed at the bottom of the collection box, and the collected initial rainwater is stored in the initial rainwater pollution collection box, and on sunny days, it is pumped into the sewage collection truck through the water pump for treatment and utilization.

[0087] The method for collecting initial rainwater from urban rainfall runoff according to the present invention comprises the following specific steps:

[0088] (1) Basic data exploration and input: Conduct basic surveys on the topography, underlying surface conditions, and pipeline network conditions in the selected urban area to clarify the sub-catchment division, number of rainwater inlets, distribution of different underlying surfaces, and road surface slope conditions in the area; conduct surveys on the water quality conditions in the selected urban area to clarify the typical pollutants in the area and select one or more typical pollutants as monitoring objects; conduct surveys on the maximum accumulation of pollutants in the selected urban area, monitor the number of sunny days in the area, establish a sunny day pollutant accumulation model through a power exponential function model, and form a surface pollutant distribution data set.

[0089] (2) After the system is built, it is set to the dry flow water inlet state, and the corresponding state of the initial rainwater pollution collection box is the opening and closing state 10. In this state, the control valve is opened and the initial rainwater pumping system is closed. At this time, the sewage flushed into the rainwater pipe on a sunny day will directly flow into the initial rainwater pollution collection box.

[0090] (3) After detecting the start of rainfall, the rainfall monitoring module monitors the rainfall process through the rain sensor and transmits it to the rainfall runoff pollution prediction module. The rainwater runoff pollution is simulated and predicted based on the rainfall process and the surface pollutant distribution data. The system is set to the rainfall inlet mode. The corresponding state of the initial rainwater pollution collection box remains in the open and closed state 10. After the runoff begins, the initial rainwater intelligent collection system begins to collect the initial rainwater;

[0091] (4) During the rainfall runoff process, the pollution peak is predicted by the rainfall runoff pollution prediction module. When the predicted rainwater concentration reaches the peak and enters the decline stage, and the rainwater quality reaches the fifth category of surface water quality standard, the module continues to monitor for five prediction steps. If the runoff concentration does not show an increasing trend, the control valve is closed. The collection box is set to the open and close state 20. In this state, the control valve and the initial rainwater pumping and drainage system are both in the closed state, and the clean rainwater enters the rainwater inlet and flows through the rainwater pipe directly into the receiving water body;

[0092] (5) During the rainfall runoff process, the initial rainwater in the collection box is monitored by the water level gauge in the initial rainwater collection unit. When the container is full of rainwater, the control valve is closed. The rainwater is directly discharged into the receiving water body;

[0093] (6) After the discharge is completed, the system is set to the dry flow water inlet state again, and the initial rainwater pollution collection box is reset to the open and close state 10, waiting for the next rainfall;

[0094] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. An intelligent urban initial rainwater collection system, characterized in that: It includes a rainfall monitoring module, an initial rainwater collection device and a control module, wherein: The rainfall monitoring module is deployed at typical sampling points in the urban area to monitor rainfall and rainfall intensity, and transmits rainfall and rainfall intensity information to the control module; The initial rainwater collection device is located at the rainwater inlet to collect initial rainwater pollution, and includes: An initial rainwater pollution collection box, a control valve, a water level gauge and an initial rainwater pumping and drainage system, wherein the initial rainwater pollution collection box is located at the water inlet of the rainwater pipe of the rainwater outlet, and a control valve is provided at the water inlet of the rainwater pipe, and rainwater is controlled to enter the initial rainwater pollution collection box through the control valve, and a water level gauge is provided in the initial rainwater pollution collection box to monitor the amount of initial rainwater collected in the initial rainwater pollution collection box; The initial rainwater pumping and drainage system is located at the bottom of the initial rainwater pollution collection box; The control module is preset with a rainfall runoff pollution prediction module, which can decide the collection time of the initial rainwater collection device through the rainfall and rainfall intensity information fed back by the rainfall monitoring module, and realize intelligent collection of initial rainwater by controlling the control valve in the initial rainwater collection device and the initial rainwater pumping and drainage system, thereby preventing highly polluted runoff from entering the receiving water body.

2. The urban initial rainwater intelligent collection system according to claim 1 is characterized in that: The rainfall runoff pollution prediction module provides pollutant source items for the pollutant transport model by constructing a sunny day pollutant accumulation model, provides hydrodynamic calculation conditions for the pollutant transport model by constructing a hydrodynamic model, and predicts the pollutant transport process through a pollutant transport model based on physical reality. For urban surface dissolved pollutants: Where H is the water depth; U is the flow velocity in the x direction; V is the flow velocity in the y direction; x and y are two perpendicular directions in the plane, x is along the direction of the water flow, and y is the direction perpendicular to the water flow; C is the average pollutant concentration along the water depth; t is time; D xx , D xy , D yx and D yy is the diffusion coefficient tensor, whose main direction is consistent with the flow direction of water; S is the source term, which represents the amount of pollutants flowing into or out of the water body per unit area on the slope per unit time; H C To control the thickness of the water layer; C C is the concentration of dissolved pollutants. For urban surface particulate pollutants: Where c is TSS concentration, mass per unit volume; m is sediment mass per unit area; e is r is the stripping rate of sediment under the splashing effect of raindrops; r r is the sediment stripping rate under the shearing action of runoff; h is the water layer thickness, q is the slope flow; d is the deposition amount of surface sediments; t is time. The pollutant concentration output by the model is compared with the emission standard. When the pollutant concentration continues to be lower than the emission standard, the collection of initial rainwater is stopped, that is, the collection time of the initial rainwater collection device is decided.

3. The urban initial rainwater intelligent collection system according to claim 1 is characterized in that: The typical sampling points in the urban area are measuring points in residential areas, commercial areas, industrial parks, roads and vegetation greening areas that can clearly show the land use type, including a typical measuring point somewhere on a main traffic artery as a road, and a typical measuring point somewhere in a residential area with relatively intensive human activities as a residential area.

4. The urban initial rainwater intelligent collection system according to claim 1 is characterized in that: The rainfall monitoring module is a rainfall sensor.

5. The urban initial rainwater intelligent collection system according to claim 1 is characterized in that: The initial rainwater drainage system includes a sewage pipe or a water pump, which is selected according to the layout of the municipal sewage pipe network. If the sewage pipe network passes through the initial rainwater pollution collection box within 3m, the sewage is discharged into the sewage pipe network through the sewage pipe; If there is no sewage pipe network near the initial rainwater pollution collection box, a water pump will be installed at the bottom of the collection box to pump water to the sewage collection vehicle for treatment and utilization on sunny days.

6. A method for collecting initial urban rainwater, based on the intelligent system for collecting initial urban rainwater according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Basic data exploration and input: Conduct basic surveys on the topography, underlying surface conditions, and pipe network conditions of the selected urban areas, and clarify the sub-catchment areas, number of rainwater outlets, and different underlying surface conditions in the area. The distribution of pollutants and the slope of the road surface; investigate the water quality of the selected areas of the city, identify the typical pollutants in the area, and select one or more typical pollutants as monitoring objects; investigate the maximum accumulation of pollutants in the selected areas of the city, monitor the number of sunny days in the area, establish a sunny day pollutant accumulation model through the power exponential function model and form a surface pollutant distribution data set; (2) After the urban initial rainwater intelligent collection system is built, it is set to a dry flow water inflow state, in which the rainfall runoff pollution prediction module is in a dormant state; the control valve is opened, the initial rainwater pumping system is closed, and the sewage flushed into the rainwater pipe on a sunny day will directly flow into the initial rainwater pollution collection box; (3) The rainfall monitoring module monitors the rainfall process and transmits it to the rainfall runoff pollution prediction module in the controller. The rainfall runoff pollution prediction module simulates and predicts the rainwater runoff pollution according to the rainfall process and the surface pollutant distribution data. The urban initial rainwater intelligent collection system is set to the rainfall inflow mode, and the rainfall runoff pollution prediction module enters the working state; the corresponding state of the initial rainwater pollution collection box is still the dry flow inflow state, that is, the control valve is opened, and the initial rainwater pumping system is closed; after the flow begins, the initial rainwater intelligent collection system starts to collect the initial rainwater; (4) During the rainfall runoff process, the pollution peak is predicted by the rainfall runoff pollution prediction module. When the predicted rainwater concentration reaches the peak and decreases, and the rainwater quality reaches the fifth category of surface water quality standard, the rainfall runoff pollution prediction module continues to monitor five prediction steps. If the runoff concentration has no growth trend, the control valve is closed, that is, the control valve and the initial rainwater pumping and drainage system are both in a closed state, and the clean rainwater enters the rainwater inlet and flows through the rainwater pipe and is directly discharged into the receiving water body; (5) During the rainfall runoff process, the initial rainwater in the initial rainwater pollution collection box is monitored by the water level gauge in the initial rainwater collection device. When the initial rainwater pollution collection box is full of rainwater, the control valve and the initial rainwater pumping and drainage system are both in a closed state, and the subsequent rainwater is directly discharged into the receiving water body; (6) After the rainfall is over, the sewage in the initial rainwater collection device is discharged through the initial rainwater pumping system. After the discharge is completed, the system is set to the dry flow water inlet state again, that is, the control valve is opened, the initial rainwater pumping system is closed, and waits for the next rainfall.

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