Industrial water-saving and carbon-reducing calculation method based on random frontier analysis and system dynamics model

Abstract

The invention belongs to the technical field of industrial water-saving and carbon-reducing calculation methods, and particularly relates to an industrial water-saving and carbon-reducing calculation method based on stochastic frontier analysis and a system dynamics model, which collects regional industrial water resources and economic data, improves the stochastic frontier analysis method, measures and calculates the industrial water efficiency, verifies the calculation precision through hypothesis test, and provides an industrial water-saving and carbon-reducing calculation method based on the stochastic frontier analysis and the system dynamics model. Based on the measurement and calculation result in the step 2, referring to the leading edge surface water consumption, calculating the industrial sub-industry water-saving potential, generalizing an industrial water taking system, establishing a conversion relation between industrial water taking and energy consumption, constructing a system dynamics model, and combining the water-saving potential in the step 3 and the conversion relation in the step 4 to calculate the total industrial water-saving carbon reduction amount.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of industrial water-saving and carbon reduction calculation methods, and particularly relates to an industrial water-saving and carbon reduction calculation method based on random frontier analysis and a system dynamics model. BACKGROUND

[0002] Under the background of global climate change and increasingly tight resource constraints, the industrial field, as a key field of water resource consumption and carbon emission, its water-saving and carbon reduction work has become a key link to achieve the "double carbon" goal and sustainable development. Accurate quantification of industrial water-saving potential and carbon reduction benefits is an important prerequisite for formulating scientific emission reduction policies and optimizing resource allocation, so the research on the industrial water-saving and carbon reduction calculation method has important theoretical and practical significance.

[0003] At present, the existing industrial water-saving and carbon reduction calculation technology has many limitations: firstly, the traditional method relies on fixed conversion coefficients for simple calculation, and does not fully consider the dynamic correlation between the economic properties of industrial production (such as industry differences, technological progress, investment scale, etc.) and water resource utilization, resulting in deviations between the calculated results of water-saving potential and the actual production rules; secondly, in the calculation of carbon emission reduction, the energy consumption chain of the whole process of industrial water intake, water transportation, water production, water drainage and reclaimed water utilization is often ignored, and the quantitative relationship between water-saving behavior and carbon emission cannot be accurately reflected; thirdly, the existing model mainly focuses on static analysis, and cannot simulate the dynamic evolution process of the water-saving and carbon reduction system under different policies, technologies or market conditions, resulting in insufficient prediction accuracy of long-term trends.

[0004] In addition, in the existing technology, the random frontier analysis method is used for efficiency calculation, but it does not effectively integrate water-saving elements and time dynamic effects, and it is difficult to accurately depict the water use efficiency differences of industrial sub-industries; the application of system dynamics model in the field of resources and environment is also limited to a single system (such as water resource system or carbon emission system), and lacks comprehensive consideration of the coupling relationship between "water resources-energy-carbon emission", which cannot meet the needs of industrial water-saving and carbon reduction collaborative management.

[0005] Therefore, there is an urgent need for a calculation method that can integrate industrial economic characteristics and water resource properties, cover the whole process of energy consumption conversion, and have dynamic simulation capability, in order to improve the accuracy and scientificity of industrial water-saving and carbon reduction calculation, and provide reliable technical support for industrial green transformation. SUMMARY

[0006] The purpose of the present application is to provide an industrial water-saving and carbon reduction calculation method based on random frontier analysis and system dynamics model to solve the above technical problems.

[0007] Therefore, the application provides an industrial water-saving and carbon reduction calculation method based on random frontier analysis and system dynamics model, which comprises the following steps: Step one: collecting regional industrial water resources and economic data; Step two: improving the random frontier analysis method, measuring industrial water efficiency, and verifying the calculation accuracy through hypothetical testing; Step three: calculating the industrial sub-industry water-saving potential based on the measurement results of step two and referring to the water consumption of the front face; Step four: generalizing the industrial water intake system and establishing the conversion relationship between industrial water intake and energy consumption; Step five: constructing a system dynamics model, combining the water-saving potential of step three and the conversion relationship of step four, and calculating the total amount of industrial water-saving and carbon reduction.

[0008] Preferably, the regional industrial water resources and economic data in step one include industrial sub-industry water resource utilization, industrial sub-industry GDP, number of employees, and water-saving investment fixed asset net value.

[0009] Preferably, the specific operation of improving the random frontier analysis method in step two comprises: Constructing a production function with total output as the output variable, employment as the basic input variable, relating water resource elements and water-saving elements, and introducing time parameters and to-be-estimated parameters; Adding a technical inefficiency equation to explain the technical inefficiency term, wherein the technical inefficiency equation is ; Wherein, ; In the formula, i=1, 2, …, n, t=1, 2, …, T, representing the industry serial number and time sequence respectively; is the technical inefficiency term, representing the technical efficiency level of the i-th industry relative to the frontier; is a random disturbance term, which is a truncated distribution of normal distribution N(0, ), so that , to ensure that obeys the non-truncated distribution of normal distribution N( ); , , , , are to-be-estimated parameters; Define the technical efficiency term as: ; Wherein represents the industrial water efficiency of the i-th industry in the t-th year; Build a Python programming environment, and use PyTorch, TensorFlow, NumPy, and Pandas libraries to measure the water use efficiency of industrial sub-sectors; The reliability of the method is verified by five hypothetical test methods, including cross-multiplication test, technical progress test, joint time effect test, Hicks technical progress test, and C-D function test. When the test results are all rejected at the 1% level, the method is determined to be reasonable and reliable.

[0010] Preferably, the specific process of calculating the industrial sub-sector water-saving potential in step three includes: Calculate the water use of the frontier surface: ; Where, is the industrial frontier surface water use of the ith industry in the t year; is the current industrial water use level; is the technical efficiency term; Calculate the sub-sector water-saving potential:

[0011] Where, is the industrial water-saving potential.

[0012] Preferably, the conversion relationship between industrial water intake and energy consumption in step four includes the following energy consumption calculation: Energy consumption of the pumping process:

[0013] Where, is the pumping energy consumption (kW・h); m is the pumping mass (kg); g is the acceleration of gravity (N / kg); h is the pumping height (m); η is the working efficiency of the lifting pump; Energy consumption of the water conveying process:

[0014] Where: is the energy consumption of water conveying (kW・h); is the water head loss along the pipeline (m), and ; is the roughness of the pipeline; Energy consumption of the water production process:

[0015] Where, is the energy consumption of water production (kW・h); to Energy consumption of mixing, flocculation, precipitation, clarification, and filtration, respectively; Energy consumption of drainage process:

[0016] wherein, is the energy consumption of drainage (kW·h); to Energy consumption of water intake, sedimentation, oxygen supply, sludge treatment, and sludge backflow, respectively; Energy consumption of reclaimed water utilization:

[0017] wherein is the energy consumption of reclaimed water utilization (kW·h); to Energy consumption of physical coagulation and sedimentation, biological treatment, membrane treatment, and reverse osmosis treatment, respectively.

[0018] Preferably, the specific operation of constructing a system dynamics model in step five comprises: Determine the system boundary, including the surface water system, the groundwater system, the tap water system, and the reclaimed water system, and clearly define the time and space limits of each system; Define system variables, including state variables, auxiliary variables, and constants; Construct variable function relationships, based on the energy consumption conversion relationship in step four, establish the calculation equations of carbon reduction / increase of each system; Perform model simulation calculation: determine the proportion of each water source, combine the water saving potential results in step three, and calculate the total industrial water saving and carbon reduction, wherein the total water saving and carbon reduction = tap water carbon reduction + surface water carbon reduction + groundwater carbon reduction - reclaimed water carbon increase.

[0019] Preferably, the system variables satisfy: The tap water system includes 17 variables, wherein the tap water carbon reduction is a state variable, and the rest are auxiliary variables or constants; The surface water system and the groundwater system each include 14 variables, wherein the surface water carbon reduction and the groundwater carbon reduction are state variables, and the remaining 13 are auxiliary variables or constants; The reclaimed water system includes 6 variables, wherein the reclaimed water carbon increase is a state variable, and the remaining 5 are constants.

[0020] Preferably, the variable function relationships include: Tap water carbon reduction = (water intake process energy consumption + water production process energy consumption + drainage process energy consumption) × carbon dioxide emission coefficient; Surface water carbon reduction = (water intake energy consumption + drainage energy consumption) × carbon dioxide emission coefficient; Carbon reduction amount of groundwater = (water consumption energy + drainage energy) x carbon dioxide emission coefficient; Carbon increase amount of reclaimed water = reclaimed water utilization amount x average power consumption of reclaimed water x carbon dioxide emission coefficient; Wherein, the carbon dioxide emission coefficient is 0.723 kg / kW·h.

[0021] Preferably, the null hypotheses of the five hypothetical tests are as follows: Cross-multiplication test: ; Technical progress test: ; Joint time effect test: ; Hicks technical progress test: ; C-D function test: .

[0022] Preferably, the method realizes quantitative calculation of industrial water-saving and carbon reduction by fusing improved stochastic frontier analysis and system dynamics model, while considering the economic attributes and water resource attributes of industrial development.

[0023] The beneficial effects of the present application are as follows: By improving the stochastic frontier analysis method, water resource elements, water-saving elements and time dynamic effects are introduced into the traditional production function, and a technical non-efficiency equation is added to explain the technical differences of the industry, and the reliability of the method can be verified by five kinds of hypothetical tests (cross-multiplication, technical progress, etc.) The water use efficiency characteristics of the industry can be accurately described. Compared with the traditional method which depends on empirical coefficients, the calculated industry water-saving potential (Delta Wit=(1-TEit) x Wit) is more in line with the economic attributes and technical development law of industrial production, and lays a precise data foundation for subsequent carbon reduction calculation.

[0024] Realize the dynamic correlation of the whole process energy consumption and carbon emission By generalizing the industrial water intake system, the energy consumption calculation formula of the whole process of water lifting, water transportation, water making, water drainage and reclaimed water utilization (such as water lifting energy consumption Ewi=mgh / (3.6 x 10 6 η), water transportation energy consumption Ewt=mghf / (3.6 x 10 6 η) and the like) is constructed, and the quantitative conversion relationship between industrial water-saving behavior and energy consumption is first established. Compared with the prior art which only accounts for the energy consumption of a single link, the present application covers the energy consumption chain of the whole life cycle of water resource utilization, so that the correlation calculation of water-saving and carbon reduction is more complete and scientific.

[0025] Dynamic simulation of multi-system synergistic carbon reduction effect A system dynamics model including four systems of surface water, groundwater, tap water, and reclaimed water is constructed, the state variables (such as surface water carbon reduction amount, reclaimed water carbon increase amount) of each system, auxiliary variables, and functional relationships are determined, and the total water-saving carbon reduction amount (total water-saving carbon reduction amount = tap water carbon reduction amount + surface water carbon reduction amount + groundwater carbon reduction amount - reclaimed water carbon increase amount) under different water source proportions and policy conditions is simulated. Compared with the static calculation method, the present application can dynamically reflect the complex interaction of the "water resources-energy-carbon emission" system, and provide a predictable quantitative basis for long-term policy making.

[0026] Strengthening industry differences and policy adaptability By calculating water use efficiency and water-saving potential by industry, and combining with the energy consumption characteristics of different water source systems, fine accounting of industrial water-saving carbon reduction is achieved. For example, by differentiating the setting of the lifting height, pipeline parameters, and other constants of tap water, surface water, and groundwater systems, the calculation results are more in line with the actual situation of regional industry. At the same time, the model includes policy influencing factors, which can quantify the influence of different policies on the amount of reclaimed water use and the amount of groundwater withdrawal, and provides technical support for targeted development of industry emission reduction strategies.

[0027] In summary, the present application breaks through the limitations of traditional methods such as static and single by combining improved stochastic frontier analysis and system dynamics model, realizes the leap from "empirical estimation" to "precise quantification" and from "single link" to "system synergy" in industrial water-saving carbon reduction, significantly improves the scientificity and practicality of the calculation results, and provides a reliable technical tool for industrial green transformation and "double carbon" target achievement. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the system architecture of the present application; Figure 2 The figure is a causal loop diagram of carbon emissions of the industrial water system of the present application; Figure 3 The figure is the principle of system dynamics modeling of the present application; Figure 4 The figure is a causal loop diagram of carbon emissions of the industrial water system of the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described clearly below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present application.

[0030] It should be noted that all the terms for indicating direction and position in the present application, such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "inner", "outer", "top", "low", "transverse", "longitudinal", "center", etc., are only used to explain the relative position relationship, connection condition, etc. between the components in a certain state (as shown in the drawings), and are only for the convenience of describing the present application, and therefore cannot be understood as a limitation on the present application. In addition, the description of "first", "second", etc. in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features.

[0031] In the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection; it can be directly connected, or indirectly connected through intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0033] The present application proposes a kind of industrial water-saving carbon reduction calculation method based on random front analysis and system dynamics model as shown in Figure 1 Through the improvement of random front analysis method, the industrial sub-industry water-saving potential is calculated, the system dynamics model is constructed based on the conversion relationship between industrial water-saving and carbon emission, so as to calculate the total amount of industrial water-saving carbon reduction. As shown in Figure 1 The technical scheme of the present application specifically includes the following steps: Step 1: collect regional industrial water resources and economic data, including: industrial sub-industry water resources utilization (surface water resources utilization, groundwater resources utilization), industrial sub-industry GDP, number of employees, water-saving investment fixed assets net value.

[0034] Step 2: improve the random front analysis method, calculate the industrial water efficiency, and verify the calculation accuracy through hypothetical test.

[0035] The specific operation process includes: Using Gross Domestic Product (Y) and Employment (L) as basic variables, with Gross Domestic Product (Y) as the output variable and Employment (L) as the input variable, the input variables are linked to water resources and water conservation factors. The water resources factor is industrial water consumption (W), and the water conservation factor is net fixed asset value (K), expressed by the following formula:

[0036] In the formula, for Industrial added value (in RMB 100 million) of the industry in year t; for Net fixed assets of the industrial sector in year t (in RMB 100 million). for Industrial employment in the industry in year t (in ten thousand people); for Industrial water consumption (100 million m3) in year t of the industry. T is a time parameter (T=1, 2, ...); , , , , , , , , , , , , , , The parameter to be estimated; (Non-negative) represents production efficiency, and the random error term. Independent of ,and .

[0037] A new technical inefficiency equation has been added, further explaining and expanding the technical inefficiency term: ; In the formula: =1, 2, ..., n, t=1, 2, ..., T, representing the industry sequence number and time series, respectively; For technical inefficiency, representing the first term. The level of technological efficiency at a relatively advanced level in each industry; The random disturbance term is a normally distributed N( The truncated distribution of ) makes , to ensure that the non-truncated distribution is subject to the normal distribution N( ); , , , , is the parameter to be estimated.

[0038] The technical efficiency term is: ; wherein represents the industrial water use efficiency of the industry in the tth year.

[0039] Build a Python programming environment, install various libraries required, including but not limited to PyTorch or TensorFlow framework for deep learning, and NumPy, Pandas and other libraries for data processing and analysis, to measure the water use efficiency of the industry.

[0040] The following five model assumptions are set for testing to verify the scientificity and reliability of the improved stochastic frontier analysis method, including: cross-multiplication test, there is no quadratic cross-multiplication effect between factors in the production technology structure.

[0041] technology progress test, there is no technological progress in the process of industrial development.

[0042] joint time effect test, the joint effect of production technology structure and technical efficiency over time is zero.

[0043] Hicks technology progress test, there is Hicks technology progress in the process of industrial development.

[0044] C-D function test, the constructed stochastic frontier production function is suitable for C-D function.

[0045] When the test results are all rejected at the 1% level, it is considered that the improved stochastic frontier analysis is reasonable and reliable in measuring the water use efficiency of the industry.

[0046] Using the improved stochastic frontier analysis method to measure the results, referring to the water use of the frontier surface, the water saving potential of the industry is calculated.

[0047] The specific operation process includes: Calculate the water use of the frontier surface, which can be expressed as follows: ; wherein: represents the industrial frontiers of the i industry in the t year water consumption; represents the current industrial water level.

[0048] The calculation of the sub-industry water-saving potential is expressed by the following formula: ; wherein: represents the industrial water-saving potential.

[0049] The industrial water intake system is generalized, and the conversion relationship between industrial water intake and energy consumption is calculated.

[0050] The specific operation process includes: The calculation of the pumping process energy consumption can be expressed by the following formula: ; wherein, is the pumping energy consumption, kW·h; is the pumping height, m; is the pumping mass, kg; is the gravitational acceleration, N / kg; is the lifting pump working efficiency.

[0051] The calculation of the water conveying process energy consumption, from the perspective of energy consumption, is the head loss along the water conveying process, which can be expressed by the following formula according to the energy conversion principle: ; ; wherein, is the water conveying energy consumption, kW·h; is the water conveying head loss; is the water intake mass, kg; is the pipe roughness; is the water conveying flow rate; is the water conveying distance; is the pipe diameter.

[0052] The calculation of the water production process energy consumption, including mixing, flocculation, sedimentation, clarification, and filtration, can be expressed by the following formula: ; wherein, is the water production process energy consumption, kW·h, is the energy consumption generated by mixing, flocculation, sedimentation, clarification, and filtration, respectively.

[0053] The calculation of the drainage process energy consumption, including water inlet, sedimentation, oxygen supply, sludge treatment, and sludge backflow, can be expressed by the following formula: ; wherein, is the energy consumption of reclaimed water utilization, kW·h, is the energy consumption of water intake, sedimentation, oxygen supply, sludge treatment, and sludge backflow, respectively.

[0054] The energy consumption of reclaimed water utilization includes physical coagulation and sedimentation, biological treatment, membrane treatment, and reverse osmosis treatment, which can be represented by the following formula: ; wherein, is the energy consumption of reclaimed water utilization, kW·h, is the energy consumption of physical coagulation and sedimentation, biological treatment, membrane treatment, and reverse osmosis treatment, respectively.

[0055] An industrial water-saving and carbon reduction system dynamics model is constructed.

[0056] The specific operation process includes: The system boundary is determined as shown in Figure 2 , the modeling principles are shown in Figure 3 , the system is divided into surface water system and groundwater system, containing surface water saving amount, groundwater saving amount, and other variables, and the time and space limits of each element in the system need to be determined.

[0057] The unit of water-saving and carbon reduction in this system is ten thousand tons, and the calculation formula of carbon dioxide emission under different water sources of industrial water system is introduced into the model; the policy influencing factors only represent the causal relationship, and the influence degree of relevant policies on the amount of reclaimed water utilization and groundwater intake is different, as shown in Figure 4 .

[0058] According to the conversion relationship between water saving and energy consumption described in step 4, there are 14 related variables in the surface water system and the groundwater system, of which the surface water carbon reduction amount is a state variable, and the remaining 13 variables are auxiliary variables and constants.

[0059] Water production process energy consumption: ; wherein, is the energy consumption of water production process, kW·h, is the water production link that produces energy consumption, and the total number is , is the energy consumption of the th water production link.

[0060] Drainage process energy consumption: ; wherein, is the energy consumption of reclaimed water utilization, kW·h, The total number of the renewable water production energy consumption links is , The energy consumption of the first renewable water production energy consumption link is

[0061] The renewable water utilization energy consumption is ; In the formula, The renewable water utilization energy consumption is kW·h, The total number of the renewable water production energy consumption links is , The energy consumption of the first renewable water production energy consumption link is

[0062] The construction of the system dynamics model includes determining the system boundary, and the system is divided into four main parts, namely, tap water system, surface water system, groundwater system and renewable water system, including tap water saving amount, surface water saving amount, groundwater saving amount, renewable water utilization amount and other variables, and the time and space limits of each element in the system need to be determined.

[0063] According to the conversion relationship between water saving and energy consumption in claim 5, it is determined that the tap water system includes 17 variables, wherein the tap water carbon reduction amount is a state variable, and the remaining variables are auxiliary variables or constants; the surface water system and the groundwater system have 14 related variables, wherein the surface water carbon reduction amount is a state variable, and the remaining 13 variables are auxiliary variables and constants; the renewable water system has 6 related variables, wherein the renewable water carbon increase amount is a state variable, and the remaining 5 variables are constants.

[0064] Model simulation calculation is performed to determine the proportions of tap water, surface water, groundwater and renewable water sources, to determine the surface water and groundwater saving amounts of each industrial industry according to the water saving potential calculation results of each industrial industry in claim 4, and to calculate the total industrial water saving and carbon reduction amount according to the variable function relationship of each system.

[0065] Simple explanation of water saving and carbon reduction related variables (taking a region in China as an example);

[0066] Simple explanation of tap water system related variables (taking a region in China as an example);

[0067] Simple explanation of surface water system related variables (taking a region in China as an example);

[0068] Simple explanation of groundwater system related variables (taking a region in China as an example);​​

[0069] Simple explanation of variables related to reclaimed water system (take a region in China as an example);

[0070] Model simulation calculation, determine the proportion of surface water and groundwater sources, according to the results of step 3, determine the water saving amount and reclaimed water utilization amount of each industrial industry, according to the function relationship of each system variable, calculate the total amount of industrial water saving and carbon reduction.

[0071] The prior art generally relies on traditional conversion coefficients when calculating industrial water saving and carbon reduction, while the present application considers both the economic properties and water resource properties of industry in the calculation of industrial water saving and carbon reduction, which is more in line with the process rules of industrial water saving and carbon reduction. The random frontier analysis method is improved to calculate the water saving potential, and on this basis, the system dynamics model is integrated to simulate the energy consumption and carbon emission rules of industrial water resource utilization process, solving the quantitative calculation problem of industrial water saving and carbon emission, and improving the calculation accuracy of industrial water saving and carbon reduction potential.

[0072] The embodiments of the present application are described above in combination with the drawings, and the embodiments and features in the embodiments in the present application can be combined with each other without conflict, the present application is not limited to the above specific embodiments, the above specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the protection scope of the claims, all of which belong to the protection of the present application.

Claims

1. A calculation method for industrial water conservation and carbon reduction based on stochastic frontier analysis and system dynamics models, characterized in that: Includes the following steps: Step 1: Collect regional industrial water resources and economic data; Step 2: Improve the stochastic frontier analysis method to calculate industrial water use efficiency and verify the calculation accuracy through hypothesis testing; Step 3: Based on the calculation results of Step 2, and with reference to the water consumption at the forefront, calculate the water-saving potential of industrial sectors. Step 4: Simplify the industrial water intake system and establish the conversion relationship between industrial water intake and energy consumption; Step 5: Construct a system dynamics model, and calculate the total amount of industrial water saving and carbon reduction by combining the water-saving potential in Step 3 and the transformation relationship in Step 4.

2. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 1, characterized in that: The regional industrial water resources and economic data mentioned in Step 1 include: water resource utilization by industrial sector, GDP by industrial sector, number of employees, and net value of fixed assets invested in water conservation.

3. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 1, characterized in that: The specific operations for improving the stochastic frontier analysis method in step two include: Construct a production function with gross domestic product as the output variable, the number of employees as the basic input variable, link water resource factors and water-saving factors, and introduce time parameters and parameters to be estimated. A new technical inefficiency equation is added, and the technical inefficiency term is explained. The technical inefficiency equation is as follows: ; in, ; In the formula: i = 1, 2, ..., n, t = 1, 2, ..., T, representing the industry sequence number and time series, respectively; For the technology inefficiency term, it represents the relatively advanced level of technology efficiency in the i-th industry; The random disturbance term is distributed according to a normal distribution N(0, 1). The truncated distribution of ) makes To ensure Follows a normal distribution N( The non-truncated distribution of ) , , , , The parameter to be estimated; Define the technical efficiency term as: ； in This represents the industrial water efficiency of industry i in year t. Set up a Python programming environment and use PyTorch, TensorFlow, NumPy, and Pandas libraries to calculate the water use efficiency of different industrial sectors. The reliability of the method was verified by five hypothesis testing methods, including cross-multiplication test, technological progress test, joint time effect test, Hicks technological progress test, and Cobb-Douglas function test. The method was deemed reasonable and reliable when all test results were rejected at the 1% level.

4. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 1, characterized in that: Step three involves calculating the water-saving potential of different industrial sectors. Calculate the water consumption at the front edge: ； in, For the water consumption at the industrial frontier of industry i in year t; This represents the current level of industrial water use. For technical efficiency; Calculate the water-saving potential by industry: in, This represents the potential for water conservation in industry.

5. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 1, characterized in that: The conversion relationship between industrial water intake and energy consumption in step four includes the following energy consumption calculations: Energy consumption during water lifting process: in, Energy consumption for water lifting (kW·h); m represents the mass of water lifted (kg); g is the acceleration due to gravity (N / kg); h is the water lifting height (m); η is used to improve pump efficiency; Energy consumption during water transfer: in, Energy consumption for water conveyance (kW·h); The head loss (m) along the water conveyance path is given, and ; Pipe roughness; Energy consumption during water production: ； in, Energy consumption for water production (kW·h); to The energy consumption for each of the mixing, flocculation, sedimentation, clarification, and filtration stages is as follows: Energy consumption during drainage process: ； in, Energy consumption for drainage (kW・h); to The energy consumption is divided into the following stages: water inlet, sedimentation, oxygen supply, sludge treatment, and sludge return. Energy consumption for reclaimed water utilization: ； in Energy consumption for reclaimed water utilization (kW·h); to The energy consumption is divided into physical coagulation and sedimentation, biological treatment, membrane treatment, and reverse osmosis treatment.

6. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 5, characterized in that: The specific operations for constructing the system dynamics model in step five include: Define the system boundaries, including surface water system, groundwater system, tap water system, and reclaimed water system, and clarify the temporal and spatial boundaries of each system; Define system variables, including state variables, auxiliary variables, and constants; Construct variable function relationships, and based on the energy consumption conversion relationship in step four, establish calculation equations for carbon reduction / carbon increase in each system; Perform model simulation calculations: determine the proportion of each water source, and combine the water-saving potential results from step three to calculate the total industrial water-saving and carbon reduction, where the total water-saving and carbon reduction = carbon reduction from tap water + carbon reduction from surface water + carbon reduction from groundwater - carbon increase from reclaimed water.

7. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 6, characterized in that: The system variables satisfy: The tap water system contains 17 variables, of which the carbon reduction of tap water is a state variable, and the rest are auxiliary variables or constants. The surface water system and the groundwater system each contain 15 variables, of which the carbon reduction of surface water and the carbon reduction of groundwater are state variables, and the remaining 13 are auxiliary variables or constants; The reclaimed water system contains 6 variables, of which the carbon increase in reclaimed water is a state variable, and the other 5 are constants.

8. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 7, characterized in that: The functional relationship between the variables includes: Carbon reduction in tap water = (Energy consumption during water intake + Energy consumption during water treatment + Energy consumption during wastewater discharge) × Carbon dioxide emission coefficient; Surface water carbon reduction = (energy consumption for water intake + energy consumption for drainage) × carbon dioxide emission coefficient; Groundwater carbon reduction = (energy consumption for water intake + energy consumption for drainage) × carbon dioxide emission coefficient; Carbon increase from reclaimed water = Reclaimed water utilization × Average electricity consumption per unit of reclaimed water × Carbon dioxide emission coefficient; The carbon dioxide emission coefficient is 0.723 kg / kW·h.

9. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 3, characterized in that: The null hypotheses for the five hypothesis tests are as follows: Cross-multiplication test: ； Verification of Technological Progress: ； Joint time effect test: ； Hicks' Technological Progress Test: ； C-D function test: 。 10. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 1, characterized in that: The method integrates improved stochastic frontier analysis and system dynamics models, while considering both the economic and water resource attributes of industrial development, to achieve quantitative calculation of industrial water conservation and carbon reduction.

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