Overflow pollution control storage pond evaluation method based on full life cycle carbon emission

Abstract

The invention discloses an overflow pollution control storage pond evaluation method based on full-life-cycle carbon emission. The method comprises the following steps: 1, selecting an intercepting-type combined-system overflow port; 2, sampling overflow sewage under typical rainfall according to time periods to obtain the water volume and quality change rule of the overflow sewage; 3, establishing an overflow pollution model; 4, calibrating and verifying the overflow pollution model; 5, performing simulation analysis on overflow pollution load control effects of the regulation and storage tank under different layouts, designs and operation schemes by using the overflow pollution model; 6, on the basis of the emission reduction effect of the regulation and storage pool on the overflow pollution load, the carbon emission amount of the regulation and storage pool in the operation process under the rainfall intensity in different recurrence periods is calculated; 7, the total carbon emission amount of the whole life cycle of the regulation and storage pond is obtained; and 8, by taking the overflow pollution load reduction amount as a denominator, calculating to obtain the reduction unit overflow pollution load carbon emission intensity. According to the method, the efficiency of the CSO regulation and storage tank is evaluated from the aspect of carbon emission, and support is provided for scheme optimization of the regulation and storage tank.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon emission accounting based on the whole life cycle, and in particular to an overflow pollution control storage pond evaluation method based on the whole life cycle carbon emission. Background Art

[0002] Combined Sewer Overflow (CSO) refers to the phenomenon that when the mixed sewage in the combined sewer system exceeds the conveying capacity under rainfall conditions, it overflows from the drain outlet and enters the environmental water body, causing pollutants to enter the environmental water body and seriously affecting the water environment quality. In order to effectively control CSO pollution, domestic and foreign researchers have proposed a variety of technical methods, including physical and chemical purification, biological and ecological treatment, and volumetric regulation and storage. Among them, the CSO regulation tank based on volumetric regulation and storage technology has received widespread attention in recent years due to its simple operation and strong applicability. During its operation, it effectively reduces the overflow frequency of CSO and the pollution load entering the environmental water body.

[0003] At present, the evaluation of CSO storage tank design schemes is mainly carried out from two aspects, namely, engineering cost and overflow pollution load reduction. In recent years, carbon emissions from CSO storage tanks have also begun to receive more attention. Existing studies often believe that the main sources of carbon emissions from CSO storage tanks are the consumption of material production and transportation, manual machinery, etc. during the construction period, and the pumping and transfer process after the storage tank is full of overflow sewage. However, there is not enough attention paid to the carbon emissions caused by overflow pollution discharge into environmental water bodies. Due to the imperfect carbon emission accounting, under the perspective of "coordinated efficiency of pollution reduction and carbon reduction", the evaluation of CSO storage tank design and operation schemes also lacks consideration from the perspective of carbon emissions, and an effective evaluation method and indicator system have not been established. This also prevents CSO storage tanks from achieving their maximum efficiency, and may even affect the realization of dual carbon goals.

[0004] Therefore, how to evaluate the performance of CSO storage tanks from the perspective of carbon emissions and provide support for the optimization of storage tank solutions has become an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the present invention provides an overflow pollution control storage tank evaluation method based on full life cycle carbon emissions, which aims to evaluate the performance of CSO storage tanks from the perspective of carbon emissions and provide support for the optimization of storage tank solutions.

[0006] To achieve the above object, the present invention discloses an overflow pollution control storage tank evaluation method based on full life cycle carbon emissions, and performs overflow pollution control storage tank design and operation scheme evaluation in an interception type combined sewer system, comprising the following steps:

[0007] Step 1: Select an overflow outlet of the intercepting combined sewer system in the study area according to the typical land use conditions in the study area;

[0008] Step 2: Sampling overflow sewage under typical rainfall according to time periods to obtain the quantity and quality change rules of overflow sewage;

[0009] Step 3: Taking the intercepting combined sewer network as the object, based on the pipeline and terrain data of the study area and combined with the current status of the intercepting combined sewer system, an overflow pollution model is established;

[0010] Step 4: calibrate and verify the overflow pollution model using measured rainfall and overflow discharge data;

[0011] Step 5: adding the overflow pollution storage tank to the overflow pollution model, and using the overflow pollution model that has been calibrated and verified to simulate and analyze the overflow pollution load control effect of the corresponding storage tank under different layouts, designs, and operation schemes;

[0012] If the result of the simulation analysis of the overflow pollution load control effect of the corresponding storage tank under different layouts, designs and operation schemes by the overflow pollution model does not meet the pollution control target, the scheme of the storage tank is adjusted until the pollution control target is met;

[0013] Step 6: Based on the emission reduction effect of the regulating reservoir on the overflow pollution load, the carbon emissions during the operation of the regulating reservoir under different return period rainfall intensities are calculated;

[0014] Step 7: According to the construction plan of the regulating reservoir, the total carbon emissions during the construction period of the regulating reservoir are calculated, and the total carbon emissions during the construction period of the regulating reservoir are added to the carbon emissions during the operation of the regulating reservoir under the rainfall intensities of different return periods to obtain the total carbon emissions of the regulating reservoir over its entire life cycle;

[0015] Step 8: Using the overflow pollution load reduction as the denominator, calculate the carbon emission intensity per unit overflow pollution load reduction.

[0016] Preferably, in step 2, based on the typical characteristics of land use in the study area, data are collected on the overflow sewage generated by each rainfall at the overflow outlet in the study area in different seasons in the past two years. The collected data should cover rainfall events with different rainfall intensities and rainfall durations in the study area, and obtain the variation characteristics of the concentration of each pollutant with the rainfall duration in each rainfall event.

[0017] Preferably, in step 3, the steps of establishing the overflow pollution model are as follows:

[0018] Step 3.1: Divide the study area into multiple sub-catchments of varying sizes according to the topography, rainwater catchment characteristics, combined sewer pipe distribution, and coastal overflow outlet settings of the study area, generalize the pipes, and count the common nodes and outlets at the end of the pipe network;

[0019] Step 3.2: Calibrate the overflow pollution model. Specifically, refer to the SWMM user manual and related literature to determine the initial parameters of the overflow pollution model.

[0020] Step 3.3: Set the number and location of CSO storage tanks in the overflow pollution model, specifically: simulate the pollution interception efficiency and calculate the carbon emissions of the centralized storage and decentralized storage schemes respectively;

[0021] Step 3.4: Determine the carbon emission accounting boundary of the overflow pollution model, including physical boundary and time boundary;

[0022] Step 3.4, determine the volume of the regulating reservoir in the overflow pollution model, specifically: based on the SWMM simulation data, use the M(V) curve to analyze the initial effect characteristics of overflow pollution SS and TN in the catchment area under different rainfall intensities, and then combine the local urban construction planning requirements for the water environment, and according to data simulation, obtain the volume of the regulating reservoir while ensuring the load reduction rate.

[0023] Preferably, in step 5, the method for reducing the overall carbon emissions of the storage tank is as follows:

[0024] Step 5.1: Starting from the material aspect, low-carbon construction materials should be used, including polypropylene, recycled plastics, and environmentally friendly concrete;

[0025] Step 5.2: Develop new building materials with lower carbon emissions and higher performance, including green concrete and bio-based materials;

[0026] Step 5.3: Use information technology to optimize the design plan, such as using BIM to optimize the design plan.

[0027] Preferably, in step 6, based on the average annual rainfall, the number of rainfall events and rainfall process according to the annual average rainfall year type are used to calculate the carbon emissions of the regulating reservoir under different rainfall intensities, and then the annual average total carbon emissions of the regulating reservoir during the operation period are accumulated, and then the total carbon emissions of the regulating reservoir during the operation period are calculated based on the entire life cycle of the operation of the regulating reservoir.

[0028] Preferably, in step 8, from the perspective of carbon emissions over the entire life cycle, the pollution reduction and carbon reduction efficiency of controlling the overflow pollution storage pond is evaluated by comparing the carbon emission intensity of reducing unit overflow pollution load.

[0029] Beneficial effects of the present invention:

[0030] The present invention determines the performance evaluation result of the CSO storage tank by calculating the relevant indicators of carbon emissions and combining the design conditions of the CSO storage tank, thus filling the gap of the lack of carbon emission-related evaluation methods in the existing CSO storage tank scheme evaluation.

[0031] The present invention calculates the carbon emissions of the CSO storage tank throughout its life cycle, so that the evaluation results can more objectively, comprehensively and truly reflect the carbon reduction performance of the CSO storage tank;

[0032] The present invention simulates and predicts the carbon emissions of the CSO storage tank during the operation and maintenance period under different return periods of rainfall by numerically simulating the overflow pollution of the interception combined sewer system with a CSO storage tank under typical rainfall events, combined with the carbon emission accounting analysis during the operation and maintenance period. Furthermore, the cumulative carbon emission accounting of rainfall events in typical years with average annual rainfall is considered, and the comprehensive accounting of carbon emissions during the operation and maintenance period of the CSO storage tank is realized over the entire life cycle;

[0033] The present invention comprehensively evaluates the two indicators of carbon emission intensity per unit volume of the CSO regulating reservoir and carbon emission intensity per unit overflow pollution load reduction. The present invention is applicable to various types of CSO regulating reservoir drainage systems, can provide an objective and scientific evaluation for the design of the CSO regulating reservoir, and provide a basis for corresponding decision-making.

[0034] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flow chart showing an embodiment of the present invention is shown.

[0036] Figure 2 A schematic diagram showing the changes in COD and SS concentrations in the catchment area with rainfall duration on August 10 in one embodiment of the present invention is shown.

[0037] Figure 3 A schematic diagram showing the changes in TP, NH4+-N and TN concentrations in the catchment area with rainfall duration on August 10 in one embodiment of the present invention is shown.

[0038] Figure 4 A schematic diagram showing the changes in COD and SS concentrations in the catchment area with rainfall duration on February 9 in one embodiment of the present invention is shown.

[0039] Figure 5 A schematic diagram showing the changes in TP, NH4+-N and TN concentrations in the catchment area with rainfall duration on February 9 in one embodiment of the present invention is shown.

[0040] Figure 6 A schematic diagram showing the changes in COD and SS concentrations in the catchment area with rainfall duration on March 8 in one embodiment of the present invention is shown.

[0041] Figure 7 A schematic diagram showing the changes in TP, NH4+-N and TN concentrations in the catchment area with rainfall duration on March 8 in one embodiment of the present invention is shown.

[0042] Figure 8 A schematic diagram showing the generalization results of the research area and the location of the measured catchment area in one embodiment of the present invention is shown.

[0043] Fig. 9 A schematic diagram showing the location of a centralized water storage reservoir in an embodiment of the present invention.

[0044] Fig.10 A schematic diagram showing the location of a water reservoir for decentralized regulation and storage in one embodiment of the present invention.

[0045] Fig.11 A schematic diagram of the carbon emission accounting boundary of a storage tank in one embodiment of the present invention is shown.

[0046] Fig.12 FIG. 1 shows an M(V) curve diagram of overflow pollution SS simulation in one embodiment of the present invention.

[0047] Fig.13 FIG. 4 shows a TN simulation M(V) curve diagram of overflow pollution in one embodiment of the present invention.

[0048] Fig.14 In one embodiment of the present invention, 3000m 3 Reduction of SS overflow in the storage tank.

[0049] Fig.15 In one embodiment of the present invention, 3000m 3 TN reduction of storage reservoir overflow.

[0050] Fig.16 In one embodiment of the present invention, 3000m 3 Reduction of COD in overflow from storage pond.

[0051] Fig.17 In one embodiment of the present invention, 1500 m 3 Reduction of SS overflow in the storage tank.

[0052] Fig.18 In one embodiment of the present invention, 1500 m 3 TN reduction of storage reservoir overflow.

[0053] Fig.19 In one embodiment of the present invention, 1500 m 3 Reduction of COD in overflow from storage pond.

[0054] Fig. 20 A schematic diagram showing the total carbon emissions of a regulating storage pool over its entire life cycle in one embodiment of the present invention is shown.

[0055] Fig.21 In one embodiment of the present invention, 3000m 3 The proportion of carbon emissions from centralized storage in regulating reservoirs over their entire life cycle.

[0056] Fig. 22 In one embodiment of the present invention, 3000m 3 The proportion of carbon emissions from decentralized storage in regulating ponds over the entire life cycle.

[0057] Fig.23 In one embodiment of the present invention, 1500 m 3 The proportion of carbon emissions from centralized storage in regulating reservoirs over their entire life cycle.

[0058] Fig.24 In one embodiment of the present invention, 1500 m 3 The proportion of carbon emissions from decentralized storage in regulating ponds over the entire life cycle.

[0059] Fig.25 A schematic diagram showing the total amount of carbon emissions during the construction phase of a storage pond in one embodiment of the present invention is shown. DETAILED DESCRIPTION

[0060] Example

[0061] like Figure 1 As shown in the figure, the overflow pollution control storage tank evaluation method based on the whole life cycle carbon emission is used to evaluate the design and operation scheme of the overflow pollution control storage tank in the interception type combined sewer system, including the following steps:

[0062] Step 1: Select an overflow outlet of the intercepting combined sewer system in the study area according to the typical land use conditions in the study area;

[0063] Step 2: Sampling overflow sewage under typical rainfall according to time periods to obtain the quantity and quality change rules of overflow sewage;

[0064] Step 3: Taking the intercepting combined sewer network as the object, based on the pipeline and terrain data of the study area and combined with the current status of the intercepting combined sewer system, an overflow pollution model is established;

[0065] Step 4: Calibrate and verify the overflow pollution model using measured rainfall and overflow discharge data;

[0066] Step 5: Add the overflow pollution storage tank to the overflow pollution model, and use the overflow pollution model that has been calibrated and verified to simulate and analyze the overflow pollution load control effect of the corresponding storage tank under different layouts, designs, and operation schemes;

[0067] If the overflow pollution model simulates and analyzes the overflow pollution load control effect of the corresponding storage tank under different layout, design and operation schemes and the result does not meet the pollution control target, the storage tank scheme shall be adjusted until the pollution control target is met;

[0068] Step 6: Based on the emission reduction effect of the storage pond on the overflow pollution load, calculate the carbon emissions during the operation of the storage pond under different return period rainfall intensities;

[0069] Step 7: According to the construction plan of the regulating reservoir, calculate the total carbon emissions during the construction period of the regulating reservoir, add the total carbon emissions during the construction period of the regulating reservoir with the carbon emissions during the operation of the regulating reservoir under different return period rainfall intensities, and obtain the total carbon emissions of the regulating reservoir over its entire life cycle;

[0070] In practical applications, the accounting method in the Technical Guidelines for Carbon Accounting and Emission Reduction Pathways for Urban Water Systems is used to calculate the total carbon emissions during the construction period of the regulating reservoir.

[0071] Step 8: Using the overflow pollution load reduction as the denominator, calculate the carbon emission intensity per unit overflow pollution load reduction.

[0072] In some embodiments, in step 2, based on the typical land use characteristics of the study area, data is collected on the overflow sewage generated by each rainfall at the overflow outlet in the study area in different seasons in the past two years. The collected data should cover rainfall events with different rainfall intensities and rainfall durations in the study area, and obtain the variation characteristics of the concentration of each pollutant with the rainfall duration in each rainfall event.

[0073] In practical applications, such as the old city area along the middle section of a river in a city, the river bank in this area is mainly commercial buildings, some of which are residential buildings, and roads and other areas are mainly hard impermeable underlying surfaces, accounting for 70% of the entire area. In addition, there are also a small amount of soft permeable surfaces such as green spaces.

[0074] According to the typical characteristics of land use in the study area, it is necessary to collect data on overflow sewage generated by three rainfalls in different seasons in the overflow outlet in the study area in the past two years. The collected data should cover rainfall events with different rainfall intensities and durations in the study area as much as possible.

[0075] like Figures 2 to 7 The following table shows the variation characteristics of pollutant concentrations with rainfall duration in these three rainfall events. Figure 2 It can be seen that suspended solids (SS) and chemical oxygen demand (COD) show a close correlation, while ammonia nitrogen (NH 4 + -N), total nitrogen (TN) and total phosphorus (TP) also have a good correlation, so this example selects the measured suspended solids (SS) and total nitrogen (TN) as representative data.

[0076] In some embodiments, in step 3, the steps of establishing the overflow pollution model are as follows:

[0077] Step 3.1: Divide the study area into multiple sub-catchments of varying sizes according to the topography, rainwater catchment characteristics, combined sewer pipe distribution, and coastal overflow outlet settings of the study area, generalize the pipes, and count the common nodes and outlets at the end of the pipe network;

[0078] In practical applications, such as the old city area along the middle section of a river in a certain city, the study area is divided into 60 sub-catchments with varying areas based on its topography, rainwater catchment characteristics, combined sewer pipe distribution and coastal overflow outlet settings. There are 48 generalized pipe sections and 70 nodes in the study area, including 22 terminal outlets. The field monitoring site is a typical drainage outlet Out13, and the corresponding catchment area is a mixed commercial and residential area with an area of ​​15.2ha, mainly commercial areas, surrounded by schools and residential areas. The underlying surface types and proportions are 60% roofs, 35% traffic roads, and 5% green spaces. The specific locations are as follows: Figure 8 shown.

[0079] Step 3.2: Calibrate the overflow pollution model. Specifically, refer to the SWMM user manual and related literature to determine the initial parameters of the overflow pollution model.

[0080] like Fig. 9 and Fig.10 As shown, step 3.3, set the number and location of CSO storage tanks in the overflow pollution model, specifically: simulate the pollution interception efficiency and calculate the carbon emissions of the centralized storage and decentralized storage schemes respectively;

[0081] Step 3.4: Determine the carbon emission accounting boundary of the overflow pollution model, including physical boundary and time boundary;

[0082] In practical applications, 30 years is selected as the evaluation period to calculate and discuss the carbon emissions of the storage pool. The carbon emissions accounting boundary is as follows: Fig.11 shown.

[0083] like Figures 12 to 19 As shown, step 3.4, determine the volume of the regulating reservoir in the overflow pollution model, specifically: based on the SWMM simulation data, use the M(V) curve to analyze the initial effect characteristics of overflow pollution SS and TN in the catchment area under different rainfall intensities, and then combine the requirements of the local urban construction plan for the water environment, and according to the data simulation, obtain the volume of the regulating reservoir while ensuring the load reduction rate;

[0084] In practical applications, in order to more efficiently evaluate the design capacity of the regulating reservoir and ensure that the regulating reservoir can effectively control the overflow water quality, this embodiment uses the M(V) curve based on SWMM simulation data to analyze the initial effect characteristics of overflow pollution SS and TN in the catchment area under different rainfall intensities. Combined with the requirements of local urban construction planning for water environment and based on data simulation, the required regulating reservoir volume is approximately 1200-2400m3 while ensuring the load reduction rate. 3 .

[0085] The impact of the storage tank layout on the interception effect: In order to calculate the carbon emissions during the operation of the storage tank, numerical simulation was used to obtain the concentrations of typical pollutants in the overflow sewage under different storage volumes and layout schemes. The simulation results show that different storage strategies have significant differences in the control effect of overflow pollutants. Compared with centralized storage, decentralized storage has a more obvious load reduction advantage in both large-volume storage and small-volume storage. Under the same volume, decentralized storage is more effective than centralized storage in mitigating overflow pollution.

[0086] The impact of the layout of regulating and storage ponds on carbon emissions: including full life cycle carbon emission accounting and full life cycle carbon emission patterns.

[0087] like Fig. 20 As shown in the figure, when the total volume of the regulating reservoir doubles, the carbon emissions over the entire life cycle will double regardless of whether it is a centralized or decentralized regulation. Therefore, when planning and designing the volume of the regulating reservoir, various factors such as carbon emissions and resource utilization efficiency should be fully considered to achieve the sustainable development and comprehensive benefits of the regulating reservoir. Possible strategies include optimizing the layout of the regulating reservoir, or adopting more scientific and efficient operating rules, such as pollutant concentration control, and combining with other LID measures.

[0088] like Figure 21 to Figure 24 As shown in the figure, under both volumes and layouts, the carbon emissions during the construction period of the storage tank dominate, accounting for more than 80% of the total carbon emissions. This shows that the construction stage of the storage tank plays a decisive role in the entire carbon emission process. In contrast, the carbon emissions caused by overflow pollution during the operation of the storage tank are relatively small. Therefore, although the increase in load reduction rate brought about by decentralized storage can significantly reduce carbon emissions during operation, it has little impact on the total carbon emissions over the entire life cycle.

[0089] In some embodiments, in step 5, the method for reducing the overall carbon emissions of the storage tank is as follows:

[0090] Step 5.1: Starting from the material aspect, low-carbon construction materials should be used, including polypropylene, recycled plastics, and environmentally friendly concrete;

[0091] Step 5.2: Develop new building materials with lower carbon emissions and higher performance, including green concrete and bio-based materials;

[0092] Step 5.3: Use information technology to optimize the design plan, such as using BIM to optimize the design plan.

[0093] In practical applications, in order to reduce the overall carbon emissions of the storage pool, the focus should be on the construction period, in which the carbon emissions of each part of the storage pool construction period are as follows: Fig.25 As shown. Material production is the main source of carbon emissions during the construction phase. In comparison, carbon emissions from material transportation and construction account for a relatively small proportion, less than 5%. Therefore, in order to effectively reduce carbon emissions: first of all, we need to start from the material aspect, and give priority to the use of low-carbon construction materials, such as polypropylene, recycled plastics, and environmentally friendly concrete; secondly, we need to focus on the development of new building materials with lower carbon emissions and higher performance, such as green concrete and bio-based materials, which can not only reduce carbon emissions generated during the production process, but also realize waste utilization; finally, we need to use advanced information technology, such as BIM, to optimize the design plan, reduce material usage and waste, and thus further reduce carbon emissions.

[0094] In some embodiments, in step 6, based on the annual average rainfall, the annual average rainfall pattern is used to calculate the carbon emissions of the regulating reservoir under different rainfall intensities, and then the annual average total carbon emissions of the regulating reservoir during the operation period are accumulated, and then the total carbon emissions of the regulating reservoir during the operation period are calculated based on the entire life cycle of the regulating reservoir.

[0095] In actual applications, the entire life cycle of a reservoir is generally 30 years.

[0096] In some embodiments, in step 8, from the perspective of full life cycle carbon emissions, the pollution reduction and carbon reduction efficiency of controlling the overflow pollution storage tank is evaluated by comparing the carbon emission intensity of reducing unit overflow pollution load.

[0097] For example, the reduction of carbon emission intensity per unit overflow pollution load in the old city along the middle section of a river in the above-mentioned city is as follows:

[0098]

[0099]

[0100] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. Evaluation method of overflow pollution control storage tank based on full life cycle carbon emissions; it is characterized by , to evaluate the design and operation plan of overflow pollution storage tank in interception combined sewer system, including the following steps: Step 1: Select an overflow outlet of the intercepting combined sewer system in the study area according to the typical land use conditions in the study area; Step 2: Sampling overflow sewage under typical rainfall according to time periods to obtain the quantity and quality change rules of overflow sewage; Step 3: Taking the intercepting combined sewer network as the object, based on the pipeline and terrain data of the study area and combined with the current status of the intercepting combined sewer system, an overflow pollution model is established; Step 4: calibrate and verify the overflow pollution model using measured rainfall and overflow discharge data; Step 5: adding the overflow pollution storage tank to the overflow pollution model, and using the overflow pollution model that has been calibrated and verified to simulate and analyze the overflow pollution load control effect of the corresponding storage tank under different layouts, designs, and operation schemes; If the result of the simulation analysis of the overflow pollution load control effect of the corresponding storage tank under different layouts, designs and operation schemes by the overflow pollution model does not meet the pollution control target, the scheme of the storage tank is adjusted until the pollution control target is met; Step 6: Based on the emission reduction effect of the regulating reservoir on the overflow pollution load, the carbon emissions during the operation of the regulating reservoir under different return period rainfall intensities are calculated; Step 7: According to the construction plan of the regulating reservoir, the total carbon emissions during the construction period of the regulating reservoir are calculated, and the total carbon emissions during the construction period of the regulating reservoir are added to the carbon emissions during the operation of the regulating reservoir under the rainfall intensities of different return periods to obtain the total carbon emissions of the regulating reservoir over its entire life cycle; Step 8: Using the overflow pollution load reduction as the denominator, calculate the carbon emission intensity per unit overflow pollution load reduction.

2. The overflow pollution control storage tank evaluation method based on full life cycle carbon emissions according to claim 1 is characterized in that: In step 2, based on the typical land use characteristics of the study area, data are collected on the overflow sewage generated by each rainfall at the overflow outlet in the study area in different seasons in the past two years. The collected data should cover rainfall events with different rainfall intensities and durations in the study area, and obtain the variation characteristics of the concentration of each pollutant with rainfall duration in each rainfall event.

3. The overflow pollution control storage tank evaluation method based on full life cycle carbon emissions according to claim 1 is characterized in that: In step 3, the steps of establishing the overflow pollution model are as follows: Step 3.1: Divide the study area into multiple sub-catchments of varying sizes according to the topography, rainwater catchment characteristics, combined sewer pipe distribution, and coastal overflow outlet settings of the study area, generalize the pipes, and count the common nodes and outlets at the end of the pipe network; Step 3.2: Calibrate the overflow pollution model. Specifically, refer to the SWMM user manual and related literature to determine the initial parameters of the overflow pollution model. Step 3.3: Set the number and location of CSO storage tanks in the overflow pollution model, specifically: simulate the pollution interception efficiency and calculate the carbon emissions of the centralized storage and decentralized storage schemes respectively; Step 3.4: Determine the carbon emission accounting boundary of the overflow pollution model, including physical boundary and time boundary; Step 3.4, determine the volume of the regulating reservoir in the overflow pollution model, specifically: based on the SWMM simulation data, use the M(V) curve to analyze the initial effect characteristics of overflow pollution SS and TN in the catchment area under different rainfall intensities, and then combine the local urban construction planning requirements for the water environment, and according to data simulation, obtain the volume of the regulating reservoir while ensuring the load reduction rate.

4. The overflow pollution control storage tank evaluation method based on full life cycle carbon emissions according to claim 1 is characterized in that: In step 5, the method of reducing the overall carbon emissions of the storage tank is as follows: Step 5.1: Starting from the material aspect, low-carbon construction materials should be used, including polypropylene, recycled plastics, and environmentally friendly concrete; Step 5.2: Develop new building materials with lower carbon emissions and higher performance, including green concrete and bio-based materials; Step 5.3: Use information technology to optimize the design plan, such as using BIM to optimize the design plan.

5. The overflow pollution control storage tank evaluation method based on full life cycle carbon emissions according to claim 1 is characterized in that: In step 6, based on the annual average rainfall, the annual average rainfall pattern is used to calculate the carbon emissions of the regulating reservoir under different rainfall intensities, and then the annual average total carbon emissions of the regulating reservoir during the operation period are accumulated. Then, based on the entire life cycle of the regulating reservoir, the total carbon emissions of the regulating reservoir during the operation period are calculated.

6. The overflow pollution control storage tank evaluation method based on full life cycle carbon emissions according to claim 1 is characterized in that: In step 8, from the perspective of carbon emissions over the entire life cycle, the pollution reduction and carbon reduction efficiency of the overflow pollution storage pond is evaluated by comparing the carbon emission intensity of reducing unit overflow pollution load.

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