A method and system for evaluating the full-cycle benefits of a bioretention basin

Abstract

The application discloses a kind of biological retention tank whole cycle benefit evaluation method and system, the method includes, according to the structure parameter of biological retention tank and internal layering, constructs biological retention experimental column;According to the change of permeability coefficient of biological retention experimental column and the inflow of biological retention tank rainwater, obtain the failure time of biological retention tank;According to the failure time of biological retention tank, obtain the whole cycle operation benefit of biological retention tank.The application is established by biological retention experimental column according to biological retention tank, the relationship between permeability coefficient change and water inflow is obtained by experiment, the service life of biological retention tank is estimated, and the running benefit of biological retention tank whole cycle is calculated.Through the evaluation method of the application, whether biological retention facility has economic benefit in its life cycle can be judged, and whether design needs to be improved or maintenance scheme is optimized.

Description

Technical Field

[0001] This invention relates to the field of bioretention pond simulation testing technology, and in particular to a method and system for evaluating the full-cycle benefits of bioretention ponds. Background Technology

[0002] Bioretention facilities, as one of the most widely used measures in sponge city construction, maintain or restore the pre-development hydrological state of a region by enhancing infiltration and evaporation. They can effectively control storm runoff at the source and improve runoff quality by utilizing natural features.

[0003] Bioretention facilities not only integrate flexibly into landscape beautification but also offer advantages in intercepting surface runoff, reducing peak flows, improving runoff quality, and replenishing groundwater resources. While numerous studies have explored the runoff quality control benefits of bioretention systems, the environmental and economic impacts of these benefits have not yet been scientifically evaluated. This hinders public understanding of the comprehensive investment and benefits of bioretention systems, leading to hesitation or concerns among individuals and private business owners regarding their application, thus affecting their widespread adoption. Furthermore, it restricts the optimization of bioretention system layout and structure, thereby limiting their ability to effectively regulate runoff quality. Future research should incorporate life-cycle assessments to better understand the comprehensive benefits of bioretention facilities. Summary of the Invention

[0004] The purpose of this invention is to provide a method for estimating the service life of a bioretention pond facility and calculating its full-cycle operating costs and benefits, thereby providing decision-makers and engineering designers with a basis for optimizing facility design and operation management.

[0005] To achieve the above objectives, the present invention provides a method for evaluating the full-cycle benefits of a bioretention pond, comprising,

[0006] Based on the structural parameters and internal stratification of the bioretention tank, a bioretention experimental column was constructed.

[0007] The failure time of the bioretention tank was obtained based on the change in the permeability coefficient of the bioretention experimental column and the rainwater inflow into the bioretention tank.

[0008] The full-cycle operational benefits of a bioretention tank are obtained based on its failure time.

[0009] Furthermore, based on the change in permeability coefficient of the bioretention experimental column and the rainwater inflow rate, the failure time of the bioretention tank was obtained, including...

[0010] A permeability coefficient decay model was constructed based on the rainwater inflow of the bioretention experimental column to obtain the total rainwater inflow when the bioretention tank fails.

[0011] The failure time of the bioretention pond was simulated based on the total rainwater inflow at the time of failure and the annual rainwater inflow of the bioretention pond.

[0012] Furthermore, the formula for calculating the total rainwater inflow when the bioretention pond fails is derived by constructing a permeability coefficient decay model based on the rainwater inflow of the bioretention experimental column.

[0013] ;

[0014] in, V 总 This represents the total rainwater inflow when the bioretention pond fails. α The attenuation rate of the permeability coefficient; K 0 represents the initial permeability coefficient of the bioretention experimental column. K 临 is the critical permeability coefficient of the biological retention experimental column.

[0015] Furthermore, the formula for calculating the failure time of the bioretention tank, which is derived from the total rainwater inflow at the time of bioretention tank failure and the annual rainwater inflow of the bioretention tank column, is as follows:

[0016] ;

[0017] ;

[0018] in, T 失效 The failure time of the biological retention tank. V 年 This represents the average annual inflow into the bioretention pond. C , A and P These represent the runoff coefficient, catchment area, and simulated annual average rainfall of the bioretention pond, respectively.

[0019] Furthermore, the full-cycle operational benefits of the bioretention tank are obtained by subtracting the initial construction and operation and maintenance costs of the bioretention tank from the benefits brought by water volume control and water purification of the bioretention tank.

[0020] Furthermore, the formula for calculating the benefits of water volume control in the bioretention tank is as follows:

[0021] ;

[0022] in, E 水量 The benefits of water volume control in a bioretention tank, where t is time. V 控制 To effectively control the annual water volume in the bioretention tank, E控制 To control the economic benefits of water usage;

[0023] The formula for calculating the benefits of water purification in a biological retention pond is as follows:

[0024] ;

[0025] in, E 水质 The benefits of water purification in biological retention ponds M 去污 This represents the total amount of pollutants removed annually by the bioretention tank. E 去污 The economic benefits of removing pollutants from bioretention ponds.

[0026] Furthermore, the cost calculation formula for the operation and maintenance of the bioretention tank is as follows:

[0027] ;

[0028] in, C 运营维护 The cost of operation and maintenance of the bioretention tank, where t is time. C 年度维护 The annual operating and maintenance cost of the bioretention tank.

[0029] Furthermore, the monitoring of permeability changes in the biological retention experimental column and the control of rainwater inflow are achieved by a buried permeability monitoring device and a connected simulated rainwater inflow device, respectively.

[0030] This invention also provides a full-cycle benefit evaluation system for bioretention ponds, including a failure time confirmation module and an operational benefit calculation module;

[0031] The failure time confirmation module is used to obtain the failure time of the bioretention tank based on the change in the permeability coefficient of the bioretention experimental column and the rainwater inflow.

[0032] The operational efficiency calculation module is used to obtain the full-cycle operational efficiency of the bioretention tank based on the failure time of the bioretention tank.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention establishes a bioretention experimental column based on a bioretention tank, and through experiments, determines the relationship between the change in permeability coefficient and the influent flow rate, estimates the service life of the bioretention tank, and calculates the operational benefits of the bioretention tank throughout its entire life cycle. The evaluation method of this invention can determine whether a bioretention facility is economically beneficial throughout its life cycle, and whether design improvements or maintenance optimizations are needed. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A flowchart of the full-cycle benefit evaluation method for bioretention ponds of the present invention is shown;

[0037] Figure 2 A schematic diagram of the structure of the bioretention pond full-cycle benefit evaluation system of the present invention is shown. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] like Figure 1 As shown, a method for evaluating the full-cycle benefits of a bioretention pond includes the following steps:

[0041] Step 1: Constructing a biological retention experimental column

[0042] Based on the structural parameters and internal stratification of the bioretention tank, a bioretention experimental column was constructed, specifically as follows:

[0043] 1) Design of the bioretention experimental column: In order to simulate the permeability and water treatment effect of the actual bioretention tank, 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 inside the bioretention experimental column and the changes in each layer. At the same time, the appropriate space can accommodate the materials in each layer, simulating the bioretention tank.

[0044] 2) Simulation of Layered Structure: The layered structure of the bioretention experimental column simulates the typical layers of a bioretention pond, including: a top layer of vegetation, a middle layer of filter media (such as sand, gravel, etc.), and a bottom drainage layer. 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 experimental column can accurately reflect the effectiveness of the bioretention pond in terms of water volume control and water purification.

[0045] 3) Install inflow device and permeability monitoring device: Connect the inflow device sequentially to the flow meter and the inlet of the bioretention experimental column, and install the flow meter at the outlet of the bioretention experimental column. The flow meter is used to monitor the inflow and outflow of the bioretention experimental column to ensure real-time recording of experimental data. Install permeability monitoring devices at different depths of the bioretention experimental column to record changes in the permeability coefficient.

[0046] Step 2: Permeability Test and Service Life Estimation

[0047] 1) Simulated Rainfall Conditions: By adjusting the inflow device, rainfall conditions of varying intensities were simulated. Multiple inflow levels were set in the experiment to simulate the impact of actual rainfall on the facility. During the experiment, the permeability coefficient of the bioretention experimental column was monitored periodically.

[0048] 2) Measurement of Permeability Coefficient Changes: By controlling the inflow rate of the inflow device, the permeability coefficient changes of the bioretention experimental column under different rainfall conditions can be recorded and evaluated. Based on different inflow rates and their corresponding permeability coefficients, the decay rate α of the permeability coefficient can be calculated using an exponential decay model. The formula for the exponential decay model of the permeability coefficient is:

[0049] ;

[0050] in, K （t） The permeability coefficient of the biological retention experimental column at different time points. K 0 represents the initial permeability coefficient of the bioretention experimental column. V 入 This represents the amount of rainwater flowing into the bioretention experimental column.

[0051] 3) Lifespan estimation: The failure criterion for a bioretention experimental column is when the permeability decreases to the critical permeability of the bioretention experimental column. K 临 At this point, the bioretention column will be unable to effectively permeate and treat runoff. In the exponential decay model of the permeability coefficient, the permeability coefficient of the bioretention column will gradually decrease with time t. K （t） = K 临 If the biological retention experimental column (biological retention tank) fails, it is considered to be ineffective.

[0052] Based on the rainwater inflow, a permeability coefficient decay model was constructed to obtain the total rainwater inflow when the bioretention pond fails.

[0053] ;

[0054] in, V总 This represents the total rainwater inflow when the bioretention pond fails. α The attenuation rate of the permeability coefficient; K 0 represents the initial permeability coefficient of the bioretention experimental column. K 临 is the critical permeability coefficient of the biological retention experimental column.

[0055] The failure time of the bioretention tank was simulated based on the total rainwater inflow at the time of its failure and the annual rainwater inflow into the bioretention tank:

[0056] ;

[0057] ;

[0058] in, T 失效 The failure time of the biological retention tank. V 年 This represents the average annual inflow into the bioretention pond. C , A and P These represent the runoff coefficient, catchment area, and simulated annual average rainfall of the bioretention pond, respectively.

[0059] Step 3: Estimation of water quantity control benefits and water quality purification benefits

[0060] Simulated rainfall experiments or monitoring of typical rainfall events were conducted on the bioretention pond. Based on the experimental or monitoring results, the annual effective controlled water volume and the total amount of pollutants removed annually by the bioretention pond were calculated. The water volume control benefits and water quality purification benefits were then calculated, as detailed below:

[0061] The formula for calculating the benefits of water volume control in a bioretention tank is as follows:

[0062] ;

[0063] in, E 水量 The benefits of water volume control in a bioretention tank, where t is time. V 控制 Annual effective water volume control for bioretention ponds (unit: m³) 3 ), E 控制 The economic benefits of controlling water usage per square meter;

[0064] The formula for calculating the benefits of water purification in a biological retention pond is as follows:

[0065] ;

[0066] in, E水质 The benefits of water purification in biological retention ponds M 去污 This refers to the total amount of pollutants removed annually by the bioretention tank (unit: kg). Removed pollutants include suspended solids, total nitrogen, and total phosphorus. E 去污 The economic benefits of removing every kilogram of pollutants from a bioretention pond.

[0067] Step 4: Full-cycle benefit assessment

[0068] Calculating the life-cycle operational benefits of a bioretention facility requires comprehensive consideration of water volume control benefits, water purification benefits, and the expected service life. Specifically, it can be divided into three main parts: benefit calculation, cost calculation, and a comprehensive assessment of life-cycle benefits.

[0069] Total benefits E 总 Benefits of water volume control and water purification in bioretention ponds:

[0070] ;

[0071] Total cost C 总 The initial investment for constructing a bioretention tank is the sum of the initial construction cost and the operation and maintenance costs of the bioretention tank.

[0072]

[0073] in, C 初期建设 Depending on the design size, materials, and construction costs of the bioretention tank, C 运营维护 The annual operating and maintenance costs of the bioretention pond include regular cleaning, vegetation restoration, and permeable layer maintenance.

[0074] The full life cycle operational benefits of bioretention ponds N 运行效益 Calculated by subtracting total cost from total benefit:

[0075] .

[0076] when N 运行效益 A positive value indicates that the bioretention pond has positive economic and environmental benefits throughout its life cycle; a negative value means that the operating cost of the facility exceeds its benefits, requiring design optimization or cost reduction. The final output can serve as a basis for the economic evaluation of the bioretention pond, and can also provide a reference for future design optimization and maintenance strategies.

[0077] Example 2

[0078] like Figure 2 As shown, a full-cycle benefit assessment system for a bioretention pond includes a failure time confirmation module and an operational benefit calculation module.

[0079] The failure time confirmation module is used to obtain the failure time of the bioretention tank based on the change in the permeability coefficient of the bioretention experimental column and the rainwater inflow.

[0080] The operational efficiency calculation module is used to obtain the full-cycle operational efficiency of the bioretention tank based on its failure time.

[0081] The execution methods of the specific modules of the system in this embodiment have been described in detail in Embodiment 1, and will not be repeated here.

[0082] Finally, it should be noted that the above description 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for evaluating the full-cycle benefits of a bioretention pond, characterized in that, include, Based on the structural parameters and internal stratification of the bioretention tank, a bioretention experimental column was constructed. The failure time of the bioretention tank was obtained based on the change in the permeability coefficient of the bioretention experimental column and the rainwater inflow into the bioretention tank. The full-cycle operational benefits of a bioretention tank are obtained based on its failure time. The failure time of the bioretention tank was obtained based on the change in the permeability coefficient of the bioretention experimental column and the rainwater inflow rate. A permeability coefficient decay model was constructed based on the rainwater inflow of the bioretention experimental column to obtain the total rainwater inflow when the bioretention tank fails. The failure time of the bioretention pond was simulated based on the total rainwater inflow at the time of failure and the annual rainwater inflow of the bioretention pond. The permeability coefficient decay model is as follows: ； in, K （t） The permeability coefficient of the biological retention experimental column at different time points. K 0 represents the initial permeability coefficient of the bioretention experimental column. V 入 The amount of rainwater flowing into the bioretention experimental column; when K （t） = K 临 If the biological retention experimental column fails, it is considered to be ineffective. The formula for calculating the total rainwater inflow when the bioretention tank fails is obtained by constructing a permeability coefficient decay model based on the rainwater inflow of the bioretention experimental column. ； in, V 总 This represents the total rainwater inflow when the bioretention pond fails. α The attenuation rate of the permeability coefficient; K 0 represents the initial permeability coefficient of the bioretention experimental column. K 临 The critical permeability coefficient of the biological retention experimental column; The formula for calculating the failure time of a bioretention tank, which is derived from the total rainwater inflow at the time of tank failure and the annual rainwater inflow of the bioretention tank column, is as follows: ； ； in, T 失效 The failure time of the biological retention tank. V 年 This represents the average annual inflow into the bioretention pond. C , A and P These represent the runoff coefficient, catchment area, and simulated annual average rainfall of the bioretention pond, respectively.

2. The method for evaluating the full-cycle benefits of a bioretention pond according to claim 1, characterized in that, The full-cycle operating benefits of the bioretention tank are calculated by subtracting the initial construction and operation and maintenance costs of the bioretention tank from the benefits brought by water volume control and water purification.

3. The method for evaluating the full-cycle benefits of a bioretention pond according to claim 2, characterized in that, The formula for calculating the benefits of water volume control in a bioretention tank is as follows: ； in, E 水量 The benefits of water volume control in a bioretention tank, where t is time. V 控制 To effectively control the annual water volume in the bioretention tank, E 控制 To control the economic benefits of water usage; The formula for calculating the benefits of water purification from a biological retention pond is as follows: ； in, E 水质 The benefits of water purification in biological retention ponds M 去污 This represents the total amount of pollutants removed annually by the bioretention tank. E 去污 The economic benefits of removing pollutants from bioretention ponds.

4. The method for evaluating the full-cycle benefits of a bioretention pond according to claim 2, characterized in that, The formula for calculating the operation and maintenance costs of a biological retention tank is as follows: ； in, C 运营维护 The cost of operation and maintenance of the bioretention tank, where t is time. C 年度维护 The annual operating and maintenance cost of the bioretention tank.

5. The method for evaluating the full-cycle benefits of a bioretention pond according to any one of claims 1-4, characterized in that, The monitoring of permeability changes in the biological retention experimental column and the control of rainwater inflow are achieved by a buried permeability monitoring device and a connected simulated rainwater inflow device, respectively.

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