A method and device for automatically controlling the operation of a low-carbon pollution control biological retention system

Abstract

The present invention discloses a method and device for automatic control of the operation of a low-carbon pollution control biological retention system, and the control method includes: using an oxidation-reduction potential monitoring electrode and a pH monitoring electrode to monitor the flooded area of ​​the polyculture biological retention system to obtain an ORP value and a pH value; constructing a multivariate nonlinear fitting formula between the total greenhouse gas radiation forcing data and the ORP value and the pH value during the denitrification process, and outputting a drainage instruction according to the calculated total greenhouse gas radiation forcing data, and performing a drainage operation on the polyculture biological retention system. Through the above control method and control system, the present invention realizes precise control of the effluent discharge of the polyculture biological retention system.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection technology, and more particularly to a method and device for automatically controlling the operation of a low-carbon pollution control biological retention system. Background Art

[0002] The rapid development of the global economy is inseparable from the highly developed industry, and a large amount of pollutants are discharged into the environment, including air, water, soil, etc. The sources of rainwater runoff pollution are diverse, and the concentration of pollutants has also increased significantly, especially nitrogen pollution, which is increasingly harmful to both humans and the environment. Therefore, many technologies and facilities have been studied for the treatment of nitrogen in rainwater runoff. Among them, bioretention facilities, as green facilities, have excellent ecology, aesthetics and certain denitrification effects, and are widely used in urban construction.

[0003] Heterotrophic system and polyculture system are two representative systems in bioretention system. For heterotrophic system and polyculture system, the microbial population and biochemical reactions involved in denitrification are very different, and the environmental indicators such as redox potential ORP and pH are also very different. In contrast, the heterotrophic system is relatively simple, and the collected data can be directly fitted by linear fitting to get a good fit. Therefore, a simple linear fitting can be used for automatic control of heterotrophic bioretention system. The polyculture system involves more complex processes such as autotrophic denitrification, sulfur cycle, and iron cycle, and a formula with a high degree of fit cannot be obtained through linear analysis.

[0004] Therefore, how to achieve automatic control of the polyculture biological retention system has become a technical problem that urgently needs to be solved in this field. Summary of the invention

[0005] In view of this, the present invention provides a method and control system for automatically controlling the operation of a low-carbon pollution control biological retention system, which is used to at least solve some of the technical problems in the background technology.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] In one aspect, the present invention discloses a method for automatically controlling the operation of a low-carbon pollution control bioretention system, comprising the following steps:

[0008] Monitoring the flooded area of ​​the polyculture bioretention system using an oxidation-reduction potential monitoring electrode and a pH monitoring electrode to obtain an ORP value and a pH value of the flooded area;

[0009] Constructing a multivariate nonlinear fitting formula between the total radiative forcing data of greenhouse gases during the denitrification process of the polyculture bioretention system and the ORP value and pH value;

[0010] Inputting the current ORP value and pH value of the flooded area into the multivariate nonlinear fitting formula to determine whether the obtained greenhouse gas total radiative forcing data meets the set threshold;

[0011] When the obtained greenhouse gas total radiative forcing data meets the set threshold, the drainage outlet of the drainage pipe of the polytrophic biological retention system is opened to perform a drainage operation on the polytrophic biological retention system.

[0012] Furthermore, before determining whether the obtained greenhouse gas total radiative forcing data meets the set threshold step, the method further includes:

[0013] Determining whether the polyculture bioretention system has completed the denitrification process based on the ORP value of the flooded area;

[0014] After the polyculture biological retention system completes the denitrification process, a determination is then made as to whether the greenhouse gas total radiation forcing data meets a set threshold.

[0015] Further, judging whether the polyculture biological retention system has completed the denitrification process according to the ORP value of the flooded area specifically includes the following steps:

[0016] S1. Obtain n ORP values ​​from the current time node to the back n minutes in the flooded area, and calculate the average, which is recorded as the average value A;

[0017] S2. Obtain n ORP values ​​from the current time node of the flooded area back n minutes to back 2n minutes, and calculate the average, which is the average value B;

[0018] S3. Calculate the difference between the mean value B and the mean value A. If the difference between the mean value B and the mean value A meets the set threshold, it is determined that the polyculture biological retention system completes the denitrification process at the current time node;

[0019] S4. If the difference between the mean B and the mean A does not meet the set threshold, steps S1-S3 are repeated until the polyculture biological retention system completes the denitrification process.

[0020] Furthermore, the multivariate nonlinear fitting formula between the total radiative forcing data of greenhouse gases in the denitrification process of the polyculture bioretention system and the ORP value and pH value specifically includes the following multivariate nonlinear fitting formula:

[0021] Y=aX1 2 +b X2 2 +c X1+dX2+e X1 X2+fX1 3 +gX1 X2 2

[0022] Where Y represents the total radiative forcing of greenhouse gases, X1 represents the ORP value, X2 represents the pH value, and a, b, c, d, e, f, and g all represent the coefficients of the multivariate nonlinear fitting formula.

[0023] Furthermore, the coefficients of the multivariate nonlinear fitting formula adopt the following values:

[0024] a=-7.0*10 -6 , b=-0.104397, c=0.101739, d=0.653923, e=-0.029738,

[0025] f=4.9944*10 -8 , g = 2.326*10 -3 .

[0026] 6. A method for automatic control of low-carbon pollution control biological retention system operation according to claim 1, characterized in that the polyculture biological retention system comprises, from top to bottom, a planting layer, a filler layer and a drainage layer; wherein,

[0027] The planting layer is used for planting plants;

[0028] The filler layer is a mixture of 65% sand, 15% soil, 10% sawdust, and 10% pyrite;

[0029] The drainage layer is filled with gravel with a diameter of 0.5-1 cm;

[0030] The flooded area for placing the redox potential monitoring electrode and the pH monitoring electrode is located in the packing layer.

[0031] On the other hand, the present invention discloses an automatic control device for low-carbon pollution control biological retention system operation, comprising:

[0032] Redox potential monitoring electrodes and pH monitoring electrodes;

[0033] Wherein, the oxidation-reduction potential monitoring electrode and the pH monitoring electrode are both placed in the flooded area of ​​the polyculture bioretention system, the oxidation-reduction potential monitoring electrode is used to collect the ORP value of the flooded area, and the pH monitoring electrode is used to collect the pH value of the flooded area;

[0034] The oxidation-reduction potential monitoring electrode is connected to an ORP monitor, and the ORP monitor is used to receive and display ORP value data and transmit it to a PLC control module;

[0035] The pH monitoring electrode is connected to a pH monitor, and the pH monitor is used to receive and display pH value data and transmit it to a PLC control module;

[0036] The PLC control module is used to input the current ORP value and pH value into a multivariate nonlinear fitting formula to determine whether the total radiation forcing data of the chamber gas during the denitrification process of the polyculture biological retention system meets the set threshold;

[0037] When the obtained greenhouse gas total radiation forcing data meets the set threshold, the PLC control module controls the electric ball valve on the drainage pipe of the polytrophic biological retention system to open, and performs drainage operation on the polytrophic biological retention system.

[0038] Preferably, the PLC control module further performs the following steps before determining whether the obtained greenhouse gas total radiative forcing data meets the set threshold value:

[0039] Determining whether the polyculture bioretention system has completed the denitrification process based on the ORP value of the flooded area;

[0040] After the polyculture biological retention system completes the denitrification process, a determination is then made as to whether the greenhouse gas total radiation forcing data meets a set threshold.

[0041] Preferably, judging whether the polyculture bioretention system has completed the denitrification process according to the ORP value of the flooded area specifically comprises the following steps:

[0042] S1. Obtain n ORP values ​​from the current time node to the back n minutes in the flooded area, and calculate the average, which is recorded as the average value A;

[0043] S2. Obtain n ORP values ​​from the current time node of the flooded area back n minutes to back 2n minutes, and calculate the average, which is the average value B;

[0044] S3. Calculate the difference between the mean value B and the mean value A. If the difference between the mean value B and the mean value A meets the set threshold, it is determined that the polyculture biological retention system has completed the denitrification process at the current time node;

[0045] S4. If the difference between the mean B and the mean A does not meet the set threshold, steps S1-S3 are repeated until the polyculture biological retention system completes the denitrification process.

[0046] Preferably, the multivariate nonlinear fitting formula specifically includes the following multivariate nonlinear fitting formula:

[0047] Y=aX1 2 +b X2 2 +c X1+dX2+e X1 X2+fX1 3 +gX1 X2 2

[0048] Where Y represents the total radiative forcing of greenhouse gases, X1 represents the ORP value, X2 represents the pH value, and a, b, c, d, e, f, and g all represent the coefficients of the multivariate nonlinear fitting formula.

[0049] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a method and device for automatically controlling the operation of a low-carbon pollution control biological retention system, which has the following beneficial effects:

[0050] The present invention controls the drainage time of the polyculture bioretention facility through the multivariate cubic relationship between ORP, pH and the radiative forced pollution caused by greenhouse gases emitted during the polyculture bioretention system to treat nitrogen pollution in rainwater runoff, thereby achieving precise control of sewage discharge from the polyculture bioretention system. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0052] Figure 1 A schematic flow chart of a polyculture biological retention facility control method provided in an embodiment of the present invention.

[0053] Figure 2 A schematic diagram of the structure of an automatic control system for a polyculture biological retention facility provided in an embodiment of the present invention.

[0054] Figure 3 A schematic structural diagram of a polyculture biological retention facility provided in an embodiment of the present invention.

[0055] Figure 4 A schematic diagram of the structure of a traditional biological retention facility provided in an embodiment of the present invention.

[0056] In the figure, 1 is a plant; 2 is a planting layer; 3 is a filler layer; 4 is a drainage layer; 5 is a flooded area; 6 is a drainage pipe outlet; 7 is a flooded area outlet; 8 is pyrite; 9 is sawdust; 10 is a monitoring port, 11 is an ORP monitoring electrode; 12 is a pH monitoring electrode; 13 is an ORP monitor; 14 is a pH monitor; 15 is a PLC controller; 16 is a solar cell; 17 is an electric ball valve. DETAILED DESCRIPTION

[0057] 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.

[0058] The embodiment of the present invention first discloses a method for automatically controlling the operation of a low-carbon pollution control biological retention system, comprising the following steps:

[0059] Monitoring the flooded area of ​​the polyculture bioretention system using an oxidation-reduction potential monitoring electrode and a pH monitoring electrode to obtain an ORP value and a pH value of the flooded area;

[0060] Constructing a multivariate nonlinear fitting formula between the total radiative forcing data of greenhouse gases during the denitrification process of the polyculture bioretention system and the ORP value and pH value;

[0061] Inputting the current ORP value and pH value of the flooded area into the multivariate nonlinear fitting formula to determine whether the obtained greenhouse gas total radiative forcing data meets the set threshold;

[0062] When the obtained greenhouse gas total radiative forcing data meets the set threshold, the drainage outlet of the drainage pipe of the polytrophic biological retention system is opened to perform a drainage operation on the polytrophic biological retention system.

[0063] Before judging whether the total radiative forcing data of greenhouse gases meets the set threshold step, it also includes:

[0064] Determining whether the polyculture bioretention system has completed the denitrification process based on the ORP value of the flooded area;

[0065] After the polyculture biological retention system completes the denitrification process, a determination is then made as to whether the greenhouse gas total radiation forcing data meets a set threshold.

[0066] Combine the following Figure 1 The control method flow chart shown in the figure describes the steps of the present application in detail. In the embodiment of the present invention, the multivariate nonlinear fitting formula is obtained by performing multivariate nonlinear fitting on the ORP, pH of the polyculture biological retention system and the total radiative forcing data of greenhouse gases in the denitrification process:

[0067] Y=aX1 2 +b X2 2 +c X1+dX2+e X1 X2+fX1 3 +gX1 X2 2

[0068] Where Y represents the total radiative forcing of greenhouse gases, X1 represents the ORP value, X2 represents the pH value, and a, b, c, d, e, f, and g all represent the coefficients of the multivariate nonlinear fitting formula.

[0069] In a specific embodiment, the coefficient is taken as follows: a = -7.0*10 -6 , b=-0.104397, c=0.101739, d=0.653923, e=-0.029738, f=4.9944*10 -8 , g = 2.326*10 -3 .

[0070] like Figure 1 As shown, the present invention inputs the monitored current ORP and pH into the multivariate nonlinear fitting formula to determine whether the value of the multivariate nonlinear fitting formula satisfies Y<0.14. If so, the polyculture biological retention system is drained.

[0071] Prior to this, it also includes judging whether the polyculture biological retention system has completed the denitrification process according to the ORP value of the flooded area; the judging process is as follows:

[0072] S1. Obtain n ORP values ​​of the flooded area from the current time node to the time period n minutes after the fallback, and calculate the average, recorded as the average A; in this embodiment, the ORP value and pH value of the flooded area are collected once a minute. When calculating the average A, n is 5. Therefore, in this step, first obtain 5 ORP value readings from the current time node to the time period 5 minutes after the fallback, and calculate their average A.

[0073] S2. Obtain n ORP values ​​of the flooded area within n minutes to 2n minutes from the current time node, and calculate the average, which is the average B; when n is 5, the average B is the average of the 5 ORP values ​​within 5 minutes to 10 minutes from the current time node.

[0074] S3. Calculate the difference between the mean value B and the mean value A. If the difference between the mean value B and the mean value A meets the set threshold, it is determined that the polyculture biological retention system has completed the denitrification process at the current time node;

[0075] S4. If the difference between the mean B and the mean A does not meet the set threshold, steps S1-S3 are repeated until the polyculture biological retention system completes the denitrification process.

[0076] exist Figure 1 In the embodiment shown, the threshold value set for the difference between the mean B and the mean A is 1.6. This judgment process is equivalent to judging whether the rate of decrease of ORP over time meets the threshold value. If not, the judgment is repeated until the threshold value is met, and the denitrification process of the polyculture biological retention system is completed.

[0077] When the denitrification process of the mixed-bioretention system is completed, the ORP value and pH value collected at the current time node are input into the multivariate nonlinear fitting formula of the greenhouse gas total radiative forcing data to determine whether the current greenhouse gas total radiative forcing data meets the set threshold. When the preset threshold is met, the drain pipe outlet of the mixed-bioretention system is opened for drainage.

[0078] The embodiment of the present invention also discloses an automatic control device for the operation of a low-carbon pollution control biological retention system, such as Figure 2 As shown, it includes: an oxidation-reduction potential monitoring electrode (ORP monitoring electrode) 11 and a pH monitoring electrode (pH monitoring electrode) 12; wherein the ORP monitoring electrode 11 and the pH monitoring electrode 12 are both placed in the flooded area 5 of the polyculture bioretention system; the ORP monitoring electrode 11 is connected to an ORP monitor 13, and the ORP monitor 13 is used to receive and display oxidation-reduction potential data, and transmit it to a PLC control module; the pH monitoring electrode 12 is connected to a pH monitor 14, and the pH monitor 14 is used to receive and display pH data, and transmit it to the PLC control module; the PLC control module is used to input the ORP value and the pH value into a multivariate nonlinear fitting formula to determine whether the total radiative forcing data of greenhouse gases in the denitrification process of the polyculture bioretention system meets the set threshold value; when the obtained total radiative forcing data of greenhouse gases meets the set threshold value, the PLC control module controls the electric ball valve 17 on the drain pipe output port 6 of the polyculture bioretention system to open, and perform a drainage operation on the polyculture bioretention system.

[0079] Specifically, the function of the PLC controller is to substitute the ORP value and pH value data into the program set inside the PLC for judgment after receiving the ORP value and pH value data, and then output instructions to control the electric ball valve 17 to open. The program includes the multivariate nonlinear fitting formula between the total radiative forcing data of greenhouse gases in the denitrification process and ORP and pH: Y = a X1 2 +b X2 2 +cX1+d X2+e X1 X2+fX1 3 +g X1X2 2 Wherein, Y represents the total radiative forcing of greenhouse gases, X1 represents the ORP value, X2 represents the pH value, a, b, c, d, e, f, and g all represent the coefficients of the multivariate nonlinear fitting formula. When the output total radiative forcing data of greenhouse gases meets the set threshold, the output control instruction opens the electric ball valve on the drain outlet 6.

[0080] Preferably, the PLC control module also performs a judgment on the denitrification process before judging whether the obtained greenhouse gas total radiation forcing data meets the set threshold step. After the polyculture biological retention system completes the denitrification process, it performs a judgment on whether the greenhouse gas total radiation forcing data meets the set threshold. For specific steps, refer to the description in the control method.

[0081] like Figure 2 As shown, the polyculture bioretention system includes, from top to bottom, a planting layer 2, a filler layer 3 and a drainage layer 4; wherein the planting layer 2 is used to plant plants 1; the filler layer 3 is a mixture of 65% sand, 15% soil, 10% sawdust 9, and 10% pyrite 8; the drainage layer 4 is filled with gravel with a diameter of 0.5-1 cm; the flooded area 5 for placing the ORP monitoring electrode 11 and the pH monitoring electrode 12 is located in the filler layer 3. The solar cell 16 provides power for the polyculture bioretention system.

[0082] A horizontally installed drainage pipe outlet 6 is provided near the bottom of the drainage layer 4. When the total radiative forcing data of greenhouse gases meets the set threshold, the PLC control module controls the electric ball valve 17 on the drainage pipe outlet 6 of the polyculture biological retention system to open. Figure 2 In the polyculture biological retention system shown, the drainage layer 4 is also provided with a flooded area drain outlet 7. The drainage pipe of the flooded area drain outlet 7 is L-shaped, so that the drainage height of the flooded area drain outlet 7 is higher than the drainage outlet of the drainage pipe. The flooded area drain outlet 7 is always kept open in order to cope with the drainage operation of the polyculture biological retention system during heavy rain or continuous rainfall.

[0083] The beneficial effects of the present invention are further illustrated by comparative experiments below.

[0084] Control trial 1

[0085] Build a Figure 2 The polyculture bioretention facility shown is used as a standard example, and from top to bottom are plant 1, planting layer 2, filler layer 3, and drainage layer 4. Plant 1 is iris, a common plant in bioretention facilities, planting layer 2 is a mixture of 80% sand + 20% soil, filler layer 3 is a mixture of 65% sand + 15% soil + 10% sawdust + 10% pyrite, and drainage layer 4 is filled with gravel with a diameter of 0.5-1cm. The device is provided with a gas sampling port, a flooded area outlet 7, an indirect monitoring port 10, and a drainage port at the end of the drainage pipe 6 from top to bottom. The facility is rained once every two days. During the rainfall, the static box method is used to seal the device, and only the flooded area outlet 7 and the monitoring port 10 are opened, and the probes of the ORP monitoring electrode 11 and the pH monitoring electrode 12 are placed at the monitoring port. After the rainfall is completed, the drainage time is controlled by the PLC, and water samples and gas are collected immediately after drainage.

[0086] like Figure 3 As shown in the figure, a polyculture bioretention facility of the same scale was built, with other conditions unchanged, except that the drainage time was not controlled. Water and air samples were taken when the rainwater stayed for 1, 2, 4, and 8 hours, respectively, as control examples 1, 2, 3, and 4.

[0087] Through actual operation, it was found that the denitrification effect of the standard example and control examples 1-4 was not much different. On the contrary, the denitrification effect of control example 4 with a long residence time was slightly reduced. The total radiation forcing of the embodiment was stable and lower than that of control examples 1-4.

[0088] Table 1 Comparison of nitrate-nitrogen removal rates between standard examples and control examples 1-4 (%)

[0089]

[0090]

[0091] Table 2 Comparison of total radiative forcing between standard example and control example 1-4 (W / m 2 )

[0092] Days Standard example Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 1 35.65 75.85 80.76 67.97 87.27 2 41.22 71.49 74.27 62.20 123.87 3 30.44 63.49 66.97 82.07 79.45 4 36.39 58.28 59.99 91.98 88.70 5 42.76 72.21 91.98 86.88 105.41 6 43.25 78.72 116.26 79.45 87.52 7 46.15 81.52 109.11 69.12 99.41 8 35.26 81.44 59.48 56.53 96.45 9 37.63 74.98 96.47 100.21 80.16 10 45.94 70.70 87.27 87.52 109.16

[0093] Control trial 2

[0094] Standard example: Build a Figure 2 The polyculture bioretention facility shown in the figure has plants, planting layer, filling layer and drainage layer from top to bottom. The plant selected is iris, a common plant in bioretention facilities. The planting layer is a mixture of 80% sand + 20% soil, the filling layer is a mixture of 65% sand + 15% soil + 10% sawdust + 10% pyrite, and the drainage layer is filled with gravel with a diameter of 0.5-1cm. The device is equipped with a gas sampling port, a flooded area outlet, an indirect monitoring port and a drainage port from top to bottom. The facility is rained every two days. During the rainfall, the static box method is used to seal the device. Only the flooded area outlet and the monitoring port are opened, and the probes of the ORP monitoring electrode and the pH monitoring electrode are placed at the monitoring port. After the rainfall is completed, the drainage time is controlled by the PLC, and water samples and gases are collected immediately after drainage.

[0095] A conventional bioretention facility was constructed Figure 4 As shown, other conditions remain unchanged, the filler layer is replaced with a mixture of 80% sand + 20% soil, and the drainage time is not controlled. Water samples and air samples are taken after the rainwater stays for 8 hours, as control example 5.

[0096] Through actual operation, it is found that the embodiment can ensure that the total radiation forcing is lower than that of the reference example 5 in most cases while the denitrification effect is much better than that of the reference example 5.

[0097] Table 3 Comparison of nitrate-nitrogen removal efficiency (%) and total radiative forcing (W / m2) between standard example and control example 1-4 2)

[0098]

[0099] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0100] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for automatically controlling the operation of a low-carbon pollution control biological retention system, characterized in that: The following steps are involved: The ORP and pH values ​​of the flooded area of ​​the polyculture bioretention system were monitored using redox potential monitoring electrodes and pH monitoring electrodes; Constructing a multivariate nonlinear fitting formula between the total radiative forcing data of greenhouse gases during the denitrification process of the polyculture bioretention system and the ORP value and pH value; Inputting the current ORP value and pH value of the flooded area into the multivariate nonlinear fitting formula to determine whether the obtained greenhouse gas total radiative forcing data meets the set threshold; When the obtained greenhouse gas total radiation forcing data meets the set threshold, the drainage outlet of the drainage pipe of the polyculture biological retention system is opened to perform drainage operation on the polyculture biological retention system; Before judging whether the total radiative forcing data of greenhouse gases meets the set threshold step, it also includes: Determining whether the polyculture bioretention system has completed the denitrification process based on the ORP value of the flooded area; After the polyculture biological retention system completes the denitrification process, a determination is then made as to whether the greenhouse gas total radiation forcing data meets a set threshold.

2. A method for automatic control of low-carbon pollution control biological retention system operation according to claim 1, characterized in that: Judging whether the polyculture bioretention system has completed the denitrification process according to the ORP value of the flooded area specifically includes the following steps: S1. Obtain n ORP values ​​from the current time node to the back n minutes in the flooded area, and calculate the average, which is recorded as the average value A; S2. Obtain n ORP values ​​from the current time node of the flooded area back n minutes to back 2n minutes, and calculate the average, which is the average value B; S3. Calculate the difference between the mean value B and the mean value A. If the difference between the mean value B and the mean value A meets the set threshold, it is determined that the polyculture biological retention system has completed the denitrification process at the current time node; S4. If the difference between the mean B and the mean A does not meet the set threshold, steps S1-S3 are repeated until the polyculture biological retention system completes the denitrification process.

3. The method for automatic control of low-carbon pollution control biological retention system according to claim 1, characterized in that: The multivariate nonlinear fitting formula between the total radiative forcing data of greenhouse gases in the denitrification process of the polyculture bioretention system and the ORP value and the pH value specifically includes the following multivariate nonlinear fitting formula: Y=aX1 2 +b X2 2 +cX1+dX2+eX1 X2+fX1 3 +gX1 X2 2 Where Y represents the total radiative forcing of greenhouse gases, X1 represents the ORP value, X2 represents the pH value, and a, b, c, d, e, f, and g all represent the coefficients of the multivariate nonlinear fitting formula.

4. A method for automatic control of low-carbon pollution control biological retention system operation according to claim 3, characterized in that: The coefficients of the multivariate nonlinear fitting formula adopt the following values: a=-7.0*10 -6 ,b=-0.104397,c=0.101739,d=0.653923,e=-0.029738, f=4.9944*10 -8 ,g=2.326*10 -3 。 5. The method for automatic control of low-carbon pollution control biological retention system according to claim 1, characterized in that: The polyculture bioretention system includes, from top to bottom, a planting layer, a filler layer and a drainage layer; wherein, The planting layer is used for planting plants; The filler layer is a mixture of 65% sand, 15% soil, 10% sawdust, and 10% pyrite; The drainage layer is filled with gravel with a diameter of 0.5-1 cm; The flooded area for placing the redox potential monitoring electrode and the pH monitoring electrode is located in the packing layer.

6. A low-carbon pollution control biological retention system operation automatic control device, characterized in that: include: Redox potential monitoring electrodes and pH monitoring electrodes; Wherein, the oxidation-reduction potential monitoring electrode and the pH monitoring electrode are both placed in the flooded area of ​​the polyculture bioretention system, the oxidation-reduction potential monitoring electrode is used to collect the ORP value of the flooded area, and the pH monitoring electrode is used to collect the pH value of the flooded area; The oxidation-reduction potential monitoring electrode is connected to an ORP monitor, and the ORP monitor is used to receive and display ORP value data and transmit it to a PLC control module; The pH monitoring electrode is connected to a pH monitor, and the pH monitor is used to receive and display pH value data and transmit it to a PLC control module; The PLC control module is used to input the current ORP value and pH value into a multivariate nonlinear fitting formula to determine whether the total radiation forcing data of the chamber gas during the denitrification process of the polyculture biological retention system meets the set threshold; Before the step of determining whether the obtained greenhouse gas total radiative forcing data meets the set threshold value, the PLC control module further performs the following steps: Determining whether the polyculture bioretention system has completed the denitrification process based on the ORP value of the flooded area; After the polyculture bioretention system completes the denitrification process, determining whether the greenhouse gas total radiation forcing data meets the set threshold is performed; When the obtained greenhouse gas total radiation forcing data meets the set threshold, the PLC control module controls the electric ball valve on the drainage pipe of the polytrophic biological retention system to open, and performs drainage operation on the polytrophic biological retention system.

7. The automatic control device for low-carbon pollution control biological retention system according to claim 6 is characterized in that: Judging whether the polyculture bioretention system has completed the denitrification process according to the ORP value of the flooded area specifically includes the following steps: S1. Obtain n ORP values ​​from the current time node to the back n minutes in the flooded area, and calculate the average, which is recorded as the average value A; S2. Obtain n ORP values ​​from the current time node of the flooded area back n minutes to back 2n minutes, and calculate the average, which is the average value B; S3. Calculate the difference between the mean value B and the mean value A. If the difference between the mean value B and the mean value A meets the set threshold, it is determined that the polyculture biological retention system completes the denitrification process at the current time node; S4. If the difference between the mean B and the mean A does not meet the set threshold, steps S1-S3 are repeated until the polyculture biological retention system completes the denitrification process.

8. The automatic control device for low-carbon pollution control biological retention system according to claim 6 is characterized in that: The multivariate nonlinear fitting formula specifically includes the following multivariate nonlinear fitting formula: Y=aX1 2 +b X2 2 +cX1+dX2+eX1 X2+fX1 3 +gX1 X2 2 Where Y represents the total radiative forcing of greenhouse gases, X1 represents the ORP value, X2 represents the pH value, and a, b, c, d, e, f, and g all represent the coefficients of the multivariate nonlinear fitting formula.

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