Method and system for evaluating full-cycle benefits of bioretention pond

Abstract

The invention discloses a full-cycle benefit evaluation method and system for a bioretention pond, and the method comprises the steps: constructing a bioretention experimental column according to the structural parameters and internal layering conditions of the bioretention pond; obtaining the failure time of the bioretention pond according to the permeability coefficient change of the bioretention experimental column and the rainwater inflow amount of the bioretention pond; according to the failure time of the bioretention pond, the full-cycle operation benefit of the bioretention pond is obtained. According to the method, the bioretention experimental column is established according to the bioretention pond, the relationship between the permeability coefficient change and the water inflow is obtained through experiments, the service life of the bioretention pond is estimated, and the full-cycle operation benefit of the bioretention pond is calculated. By means of the evaluation method, whether the bioretention facility has economic benefits in the life cycle of the bioretention facility or not and whether the design needs to be improved or the maintenance scheme needs to be optimized or not can be judged.

Description

Technical Field

[0001] The invention relates to the technical field of biological retention pond simulation testing, and in particular to a full-cycle benefit evaluation method and system for a biological retention pond. Background Art

[0002] As one of the most widely used measures in sponge city construction, bioretention facilities can maintain or restore the hydrological state of an area before development by enhancing infiltration and evaporation. They can effectively control storm runoff at the source and improve runoff quality by utilizing natural characteristics.

[0003] Bioretention facilities can not only be flexibly integrated into the landscape beautification environment, but also have advantages in intercepting surface runoff, reducing peak flow, improving runoff quality, and replenishing groundwater resources. Although there have been many studies on the benefits of bioretention systems in regulating runoff water quality, the environmental and economic impacts of such benefits have not been scientifically evaluated. On the one hand, it hinders the public's scientific understanding of the comprehensive input and benefits of bioretention systems, resulting in hesitation or concerns among individuals or private owners when applying bioretention technical measures, affecting their promotion and application; on the other hand, it restricts the layout or structural optimization of bioretention systems, thereby affecting the bioretention system's more effective function of regulating runoff water quality. Future research should be combined with life cycle assessment to better understand the comprehensive benefits of bioretention facilities. Summary of the invention

[0004] The purpose of the present invention is to propose a method that can estimate the service life of biological retention pond facilities and calculate their full-cycle operating costs and benefits, thereby providing decision makers and engineering designers with a basis for optimizing facility design and operation management.

[0005] In order to achieve the above object, the present invention provides a method for evaluating the full cycle benefits of a biological retention pond, comprising: According to the structural parameters and internal stratification of the bioretention pool, a bioretention experimental column was constructed; According to the change of permeability coefficient of the bioretention test column and the amount of rainwater inflow into the bioretention pond, the failure time of the bioretention pond is obtained; The full cycle operation benefits of the bioretention pond are obtained based on the failure time of the bioretention pond.

[0006] Furthermore, according to the change of the permeability coefficient of the bioretention test column and the amount of rainwater inflow, the failure time of the bioretention pond is obtained, including: According to the rainwater inflow of the bioretention experimental column, a permeability coefficient attenuation model was constructed to obtain the total rainwater inflow when the bioretention tank failed. The failure time of the bioretention pond is simulated based on the total rainwater inflow when the bioretention pond fails and the annual rainwater inflow of the bioretention pond.

[0007] Furthermore, the permeability coefficient attenuation model is constructed according to the rainwater inflow of the bioretention test column to obtain the calculation formula for the total rainwater inflow when the bioretention tank fails: ; in, V 总 is the total rainwater inflow when the bioretention pond fails, α is the attenuation rate of permeability coefficient; K 0 is the initial permeability coefficient of the bioretention test column, K 临 is the critical permeability coefficient of the bioretention test column.

[0008] Furthermore, the calculation formula for the failure time of the bioretention pond obtained by simulating the total rainwater inflow when the bioretention pond fails and the annual rainwater inflow of the bioretention pond column is: ; ; in, T 失效 is the failure time of the bioretention pond, V 年 is the average annual inflow to the bioretention pond, C , A and P are the runoff coefficient of the bioretention pond, the catchment area and the simulated annual average rainfall, respectively.

[0009] Furthermore, the full-cycle operating benefit of the biological retention pond is obtained by deducting the costs incurred in the initial construction and operation and maintenance of the biological retention pond from the benefits brought by the water volume control and water quality purification of the biological retention pond.

[0010] Furthermore, the benefit calculation formula of water volume control in biological retention pond is: ; in, E 水量 is the benefit of water volume control in the biological retention pond, t is time, V 控制 To effectively control the water volume in the bioretention pond, E 控制 Economic benefits of controlling water volume; The profit calculation formula of water purification in biological retention pond is: ; in, E 水质 Benefits of water purification in bioretention ponds, M去污 is the total amount of pollutants removed annually by the bioretention pond, E 去污 Economic benefits of pollutant removal in bioretention ponds.

[0011] Furthermore, the cost calculation formula for the operation and maintenance of the bioretention pond is: ; in, C 运营维护 is the cost of operation and maintenance of the bioretention pond, t is time, C 年度维护 Annual operation and maintenance costs of the bioretention pond.

[0012] Furthermore, the monitoring of permeability changes of the bioretention test column and the control of rainwater inflow are respectively achieved by the buried permeability monitoring device and the connected simulated rainwater inflow device.

[0013] The present invention also provides a full-cycle benefit evaluation system for a biological retention pond, including an expiration time confirmation module and an operation benefit calculation module; The failure time confirmation module is used to obtain the failure time of the bioretention tank according to the change of the permeability coefficient of the bioretention experimental column and the amount of rainwater inflow; The operation benefit calculation module is used to obtain the full-cycle operation benefit of the biological retention pond according to the failure time of the biological retention pond.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention establishes a bioretention experimental column according to the bioretention pool, obtains the relationship between the permeability coefficient change and the water inflow through the experiment, estimates the service life of the bioretention pool, and calculates the operation benefit of the whole cycle of the bioretention pool. Through the evaluation method of the present invention, it can be judged whether the bioretention facility has economic benefits during its life cycle, and whether it needs to improve the design or optimize the maintenance plan. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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 some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 A flow chart showing the method for evaluating the full cycle benefits of a biological retention pond of the present invention is shown; Figure 2 The schematic diagram of the structure of the full-cycle benefit evaluation system of the biological retention pond of the present invention is shown. DETAILED DESCRIPTION

[0017] The following will be combined with the specific embodiments of the present invention and the drawings of the specification 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.

[0018] Example 1 like Figure 1 As shown, a method for evaluating the full cycle benefits of a biological retention pond includes the following steps: Step 1: Construct a bioretention test column According to the structural parameters and internal stratification of the bioretention pool, a bioretention experimental column was constructed, specifically, 1) Design of the bioretention test column: In order to simulate the permeability and water treatment effect of the actual bioretention pond, a transparent PVC pipe with a diameter of 10~30cm and a height of 1~1.5m is used as the material. This impermeable material is convenient for observing the water flow conditions and changes in each layer inside the bioretention test column. At the same time, the appropriate space can accommodate materials at each layer to simulate the bioretention pond.

[0019] 2) Simulation of layered structure: The layered structure of the bioretention test column simulates the typical layers of a bioretention pond, including: a plant layer on the surface, a filter material layer (such as sand, gravel, etc.) in the middle, and a drainage layer at the bottom. The thickness and material type of each layer are adjusted according to the design of the bioretention pond to ensure that the evaluation of the bioretention test column can accurately reflect the effect of the bioretention pond in water volume control and water quality purification.

[0020] 3) Install the inflow device and permeability coefficient monitoring device: Connect the inflow device to the flow meter and the inlet of the bioretention test column in turn, and install the flow meter at the outlet of the bioretention test column. The flow meter is used to monitor the inflow and outflow of the bioretention test column to ensure that the experimental data can be recorded in real time. Install permeability coefficient monitoring devices at different depths of the bioretention test column to record the changes in the permeability coefficient of the bioretention test column.

[0021] Step 2: Permeability test and service life estimation 1) Simulated rainfall conditions: By adjusting the inflow device, rainfall conditions of different intensities are simulated. In the experiment, multiple inflow levels are set to simulate the impact of actual rainfall on the facility. During the experiment, the permeability coefficient of the bioretention test column is regularly monitored.

[0022] 2) Measurement of permeability coefficient changes: By controlling the inflow rate of the inflow device, the permeability coefficient changes of the bioretention test column under different rainfall conditions can be recorded and evaluated. According to different inflow rates and their corresponding permeability coefficients, the exponential decay model can be applied to calculate the decay rate α of the permeability coefficient. The formula of the permeability coefficient exponential decay model is: ; in, K （t） is the permeability coefficient of the bioretention test column at different times, K 0 is the initial permeability coefficient of the bioretention test column, V 入 is the rainwater inflow into the bioretention test column.

[0023] 3) Estimation of service life: The failure standard of the bioretention test column is when the permeability coefficient decreases to the critical permeability coefficient of the bioretention test column K 临 , at this time, the bioretention test column will not be able to effectively infiltrate and treat runoff. In the permeability coefficient exponential decay model, as time t passes, the permeability coefficient of the bioretention test column will gradually decrease. K （t） = K 临 When the bioretention test column (bioretention tank) is considered to be ineffective.

[0024] According to the rainwater inflow, the permeability coefficient attenuation model is constructed to obtain the total rainwater inflow when the biological retention pond fails: ; in, V 总 is the total rainwater inflow when the bioretention pond fails, α is the attenuation rate of permeability coefficient; K 0 is the initial permeability coefficient of the bioretention test column, K 临 is the critical permeability coefficient of the bioretention test column.

[0025] The failure time of the bioretention pond is simulated based on the total rainwater inflow when the bioretention pond fails and the annual rainwater inflow of the bioretention pond: ; ; in, T 失效 is the failure time of the bioretention pond, V 年 is the average annual inflow to the bioretention pond, C , A andP are the runoff coefficient of the bioretention pond, the catchment area and the simulated annual average rainfall, respectively.

[0026] Step 3: Estimation of water quantity control benefits and water quality purification benefits Conduct simulated rainfall experiments on the bioretention pond or monitor typical rainfall events. Calculate the annual effective controlled water volume and the total amount of pollutants removed each year based on the experimental or monitoring results, and then calculate the water volume control benefit and water quality purification benefit, as follows: The profit calculation formula of water volume control in biological retention pond is: ; in, E 水量 is the benefit of water volume control in the biological retention pond, t is time, V 控制 The annual effective controlled water volume of the biological retention pond (unit: m 3 ), E 控制 Economic benefits of controlling water volume per square meter; The profit calculation formula of water purification in biological retention pond is: ; in, E 水质 Benefits of water purification in bioretention ponds, M 去污 is the total amount of pollutants removed annually in the bioretention pond (unit: kg). The pollutants removed include suspended solids, total nitrogen, total phosphorus, etc. E 去污 Economic benefits for each kilogram of pollutant removed from a bioretention pond.

[0027] Step 4: Full-cycle benefit evaluation When calculating the full life cycle operating benefits of bioretention facilities, it is necessary to comprehensively consider the water volume control benefits, water quality purification benefits and the expected service life. Specifically, it can be divided into three main parts: benefit calculation, cost calculation and comprehensive evaluation of the full life cycle benefits.

[0028] Total Benefit E 总 Benefits of water quantity control and water quality purification in biological retention ponds: ; Total Cost C 总 The one-time investment in the construction of the bioretention pond is the sum of the initial construction cost and the operation and maintenance cost of the bioretention pond:

[0029] in, C 初期建设 Depends on the design scale, materials and construction costs of the bioretention pond. C 运营维护 The annual operation and maintenance costs of the bioretention pond include regular cleaning, vegetation restoration, infiltration layer maintenance, etc.

[0030] The full life cycle benefits of bioretention ponds N 运行效益 , calculated by subtracting total costs from total benefits: .

[0031] when N 运行效益 When it is positive, it means that the bioretention pond has positive economic and environmental benefits during its life cycle; when it is negative, it means that the operating cost of the facility is higher than the benefits it generates, and the design needs to be optimized or the cost needs to be reduced. The final output can be used as the basis for the economic evaluation of the bioretention pond, and can also provide a reference for future design optimization and maintenance strategies.

[0032] Example 2 like Figure 2 As shown, a full-cycle benefit evaluation system for a biological retention pond includes an expiration time confirmation module and an operation benefit calculation module; The failure time confirmation module is used to obtain the failure time of the bioretention tank according to the change of the permeability coefficient of the bioretention experimental column and the amount of rainwater inflow; The operation benefit calculation module is used to obtain the full-cycle operation benefit of the biological retention pond according to the failure time of the biological retention pond.

[0033] The execution method of the specific modules of the system of this embodiment has been described in detail in Embodiment 1 and will not be repeated here.

[0034] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for evaluating the full cycle benefits of a biological retention pond, characterized in that: include, According to the structural parameters and internal stratification of the bioretention pool, a bioretention experimental column was constructed; According to the change of permeability coefficient of the bioretention test column and the amount of rainwater inflow into the bioretention pond, the failure time of the bioretention pond is obtained; The full cycle operation benefits of the bioretention pond are obtained based on the failure time of the bioretention pond.

2. The method for evaluating the full cycle benefits of a biological retention pond according to claim 1, characterized in that: According to the change of permeability coefficient of the bioretention test column and the amount of rainwater inflow, the failure time of the bioretention pond is obtained, including: According to the rainwater inflow of the bioretention experimental column, a permeability coefficient attenuation model was constructed to obtain the total rainwater inflow when the bioretention tank failed. The failure time of the bioretention pond is simulated based on the total rainwater inflow when the bioretention pond fails and the annual rainwater inflow of the bioretention pond.

3. The method for evaluating the full cycle benefits of a biological retention pond according to claim 2, characterized in that: The calculation formula for the total rainwater inflow when the bioretention tank fails by constructing a permeability coefficient attenuation model based on the rainwater inflow of the bioretention experimental column is: ； in, V 总 is the total rainwater inflow when the bioretention pond fails, α is the attenuation rate of permeability coefficient; K 0 is the initial permeability coefficient of the bioretention test column, K 临 is the critical permeability coefficient of the bioretention test column.

4. The method for evaluating the full cycle benefits of a biological retention pond according to claim 3, characterized in that: The calculation formula for the failure time of the bioretention pond obtained by simulating the total rainwater inflow when the bioretention pond fails and the annual rainwater inflow of the bioretention pond column is: ； ； in, T 失效 is the failure time of the bioretention pond, V 年 is the average annual inflow to the bioretention pond, C , A and P are the runoff coefficient of the bioretention pond, the catchment area and the simulated annual average rainfall, respectively.

5. The method for evaluating the full cycle benefits of a biological retention pond according to claim 4, characterized in that: The full-cycle operating benefit of the biological retention pond is obtained by deducting the costs of initial construction and operation and maintenance of the biological retention pond from the benefits brought by water volume control and water quality purification of the biological retention pond.

6. The method for evaluating the full cycle benefits of a biological retention pond according to claim 5, characterized in that: The profit calculation formula of water volume control in biological retention pond is: ； in, E 水量 is the benefit of water volume control in the biological retention pond, t is time, V 控制 To effectively control the water volume in the bioretention pond, E 控制 Economic benefits of controlling water volume; The profit calculation formula of water purification in biological retention pond is: ； in, E 水质 Benefits of water purification in bioretention ponds, M 去污 is the total amount of pollutants removed annually by the bioretention pond, E 去污 Economic benefits of pollutant removal in bioretention ponds.

7. The method for evaluating the full cycle benefits of a biological retention pond according to claim 5, characterized in that: The cost calculation formula for the operation and maintenance of the biological retention pond is: ； in, C 运营维护 is the cost of operation and maintenance of the bioretention pond, t is time, C 年度维护 Annual operation and maintenance costs of the bioretention pond.

8. The method for evaluating the full cycle benefits of a biological retention pond according to any one of claims 1 to 7, characterized in that: The monitoring of permeability changes in the bioretention test column and the control of rainwater inflow are respectively achieved by a buried permeability monitoring device and a connected simulated rainwater inflow device.

9. A full-cycle benefit evaluation system for a biological retention pond, characterized in that: Including failure time confirmation module and operation benefit calculation module; The failure time confirmation module is used to obtain the failure time of the bioretention tank according to the change of the permeability coefficient of the bioretention experimental column and the amount of rainwater inflow; The operation benefit calculation module is used to obtain the full-cycle operation benefit of the biological retention pond according to the failure time of the biological retention pond.

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