An industrial water-saving and carbon-reducing calculation method based on random front analysis and system dynamics model

Abstract

This invention belongs to the technical field of industrial water conservation and carbon reduction calculation methods, and particularly relates to an industrial water conservation and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model. It collects regional industrial water resources and economic data, improves the stochastic frontier analysis method, calculates industrial water use efficiency, and verifies the calculation accuracy through hypothesis testing. Based on the calculation results of step two, and referring to the water consumption at the frontier, it calculates the water conservation potential of different industrial sectors, generalizes the industrial water intake system, establishes the conversion relationship between industrial water intake and energy consumption, constructs a system dynamics model, and combines the water conservation potential from step three and the conversion relationship from step four to calculate the total industrial water conservation and carbon reduction.

Description

Technical Field

[0001] This invention 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 stochastic frontier analysis and system dynamics model. Background Technology

[0002] Against the backdrop of increasingly tight global climate change and resource constraints, the industrial sector, as a major consumer of water resources and emitter of carbon, has made water conservation and carbon reduction a crucial link in achieving "dual carbon" goals and sustainable development. Accurately quantifying the water-saving potential and carbon reduction benefits of industry is an important prerequisite for formulating scientific emission reduction policies and optimizing resource allocation. Therefore, research on calculation methods for industrial water conservation and carbon reduction has significant theoretical and practical implications.

[0003] Currently, existing industrial water conservation and carbon reduction calculation technologies have many limitations: First, traditional methods often rely on fixed conversion factors for simple calculations, failing to fully consider the dynamic relationship between the economic attributes of industrial production (such as industry differences, technological progress, and investment scale) and water resource utilization, leading to discrepancies between the calculated water conservation potential and actual production patterns. Second, in carbon reduction accounting, energy consumption and carbon emissions of a single link are often calculated in isolation, ignoring the entire energy consumption chain of industrial water intake, transmission, treatment, drainage, and reclaimed water utilization, making it difficult to accurately reflect the quantitative relationship between water conservation behavior and carbon emissions. Third, existing models mostly focus on static analysis and cannot simulate the dynamic evolution of water conservation and carbon reduction systems under different policy, technological, or market conditions, resulting in insufficient accuracy in predicting long-term trends.

[0004] Furthermore, while existing technologies use stochastic frontier analysis for efficiency measurement, they fail to effectively integrate water-saving factors with time-based dynamic effects, making it difficult to accurately characterize the differences in water efficiency across different industrial sectors. The application of system dynamics models in the resource and environmental field is also mostly limited to single systems (such as water resource systems or carbon emission systems), lacking a comprehensive consideration of the coupling relationship between "water resources-energy-carbon emissions," and thus failing to meet the needs of coordinated management of industrial water conservation and carbon reduction.

[0005] Therefore, there is an urgent need for a calculation method that can integrate the characteristics of industrial economy and water resource attributes, cover the entire process of energy consumption conversion, and have dynamic simulation capabilities, so as to improve the accuracy and scientific nature of industrial water conservation and carbon reduction calculations and provide reliable technical support for the green transformation of industry. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned technical problems by providing an industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics models.

[0007] In view of this, the present invention provides a method for calculating industrial water conservation and carbon reduction based on stochastic frontier analysis and system dynamics models, comprising 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.

[0008] Preferably, the regional industrial water resources and economic data mentioned in step one include: water resource utilization by industrial sector, GDP by industrial sector, number of employees, and net value of fixed assets invested in water conservation.

[0009] Preferably, the specific operations of the improved 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 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.

[0010] Preferably, the specific process for calculating the water-saving potential of industrial sectors in step three includes: Calculate the water consumption at the front edge: ; in, This represents 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:

[0011] in, This represents the potential for water conservation in industry.

[0012] Preferably, 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:

[0013] 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:

[0014] 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:

[0015] 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:

[0016] 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:

[0017] 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.

[0018] Preferably, 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.

[0019] Preferably, 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 14 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.

[0020] Preferably, the variable functional relationship 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.

[0021] Preferably, 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: .

[0022] Preferably, 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.

[0023] The beneficial effects of this invention are: By improving the stochastic frontier analysis method, this invention introduces water resource factors, water-saving factors, and time dynamic effects into the traditional production function, and adds a new technical inefficiency equation to explain industry-specific technological differences. Combined with five hypothesis tests (cross-multiplication, technological progress, etc.) to verify the reliability of the method, it can accurately characterize the water efficiency features of different industrial sectors. Compared to traditional methods that rely on empirical coefficients, the water-saving potential calculated by this invention for different sectors (ΔWit=(1-TEit)×Wit) better reflects the economic attributes and technological development patterns of industrial production, laying a precise data foundation for subsequent carbon reduction calculations.

[0024] Achieve dynamic correlation between energy consumption and carbon emissions throughout the entire process. By generalizing the industrial water intake system, an energy consumption calculation formula for the entire process of water lifting, water transmission, water treatment, drainage, and reclaimed water utilization is constructed (e.g., water lifting energy consumption Ewi=mgh / (3.6×10)). 6 η), Water conveyance energy consumption Ewt=mghf / (3.6×10 6 This invention, for the first time, systematically establishes a quantitative conversion relationship between industrial water-saving behavior and energy consumption. Compared with existing technologies that isolate and calculate energy consumption in a single link, this invention covers the energy consumption chain of the entire life cycle of water resource utilization, making the correlation calculation between water saving and carbon reduction more complete and scientific.

[0025] Dynamic simulation of multi-system synergistic carbon reduction effect A system dynamics model is constructed, encompassing four major systems: surface water, groundwater, tap water, and reclaimed water. This model clarifies the state variables (such as carbon reduction from surface water and carbon increase from reclaimed water), auxiliary variables, and functional relationships for each system. Simulation calculations are then used to calculate the total water-saving and carbon-reduction amounts under different water source ratios and policy conditions (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). Compared to static calculation methods, this invention can dynamically reflect the complex interactive relationships within the "water resources-energy-carbon emissions" system, providing predictable quantitative evidence for long-term policy formulation.

[0026] Strengthen industry differentiation and policy adaptability By calculating water use efficiency and water-saving potential across different industries and combining the energy consumption characteristics of various water source systems, a refined accounting of industrial water conservation and carbon reduction has been achieved. For example, by setting different constants such as the lifting height and pipeline parameters for tap water, surface water, and groundwater systems, the calculation results are made more consistent with the actual situation of regional industries. At the same time, the model incorporates policy influencing factors, which can quantify the impact of different policies on the utilization of reclaimed water and the amount of groundwater extracted, providing technical support for the development of targeted industry emission reduction strategies.

[0027] In summary, this invention, by integrating improved stochastic frontier analysis and system dynamics models, breaks through the limitations of traditional static and singular methods, and achieves a leap from "empirical estimation" to "precise quantification" and from "single link" to "system synergy" in industrial water conservation and carbon reduction. It significantly improves the scientificity and practicality of the calculation results and provides a reliable technical tool for industrial green transformation and the achievement of "dual carbon" goals. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the system architecture of the present invention; Figure 2 This is a causal loop diagram of carbon emissions from an industrial water system according to the present invention. Figure 3 This invention provides the principles for system dynamics modeling. Figure 4 This is a causal loop diagram of carbon emissions from an industrial water system according to the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0030] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0031] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] This invention proposes, as follows Figure 1 This paper presents a method for calculating industrial water conservation and carbon reduction based on stochastic frontier analysis and system dynamics models. By improving the stochastic frontier analysis method, it calculates the water conservation potential of different industrial sectors. Based on the relationship between industrial water conservation and carbon emission conversion, it constructs a system dynamics model to calculate the total industrial water conservation and carbon reduction. Figure 1 As shown, the technical solution of the present invention specifically includes the following steps: Step 1: Collect regional industrial water resources and economic data, including: water resource utilization by industrial sector (surface water resource utilization, groundwater resource utilization), GDP, employment, and net value of fixed assets invested in water conservation by industrial sector.

[0034] Step 2: Improve the stochastic frontier analysis method to calculate industrial water use efficiency, and verify the accuracy of the calculation through hypothesis testing.

[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 Follows a normal distribution N( The non-truncated distribution of ) , , , , These are parameters to be estimated.

[0038] The technical efficiency item is: ; In the formula, express Industrial water efficiency in the industry in year t.

[0039] Set up a Python programming environment and install the necessary libraries, including but not limited to the PyTorch or TensorFlow framework for deep learning, and libraries such as NumPy and Pandas for data processing and analysis, to calculate the water efficiency of different industrial sectors.

[0040] Five hypothesis tests are set up to verify the scientific validity and reliability of the improved stochastic frontier analysis method, including: Cross-multiplication test, There is no secondary cross-multiplication effect between factors in the production technology structure.

[0041] Technological progress test There was no technological progress in the process of industrial development.

[0042] Joint time effect test, The combined time effect of production technology structure and technical efficiency is zero.

[0043] Hicks's Technological Progress Test Hicks' technological progress occurred during the process of industrial development.

[0044] C-D function test The constructed stochastic frontier production function is applicable to the C-D function.

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

[0046] Using the results of the improved stochastic frontier analysis method and referring to the water consumption at the frontier, the water-saving potential of industrial sectors is calculated.

[0047] The specific operation process includes: The water consumption at the water front is calculated using the following formula: ; In the formula: This represents the water consumption at the industrial frontier of industry i in year t. This indicates the current level of industrial water use.

[0048] The water-saving potential for different industries is calculated using the following formula: ; In the formula: This indicates the potential for water conservation in industry.

[0049] Simplify industrial water intake systems and calculate the conversion relationship between industrial water intake and energy consumption.

[0050] The specific operation process includes: The energy consumption of the water lifting process can be expressed by the following formula: ; In the formula, Energy consumption for water lifting, kW·h; The height of the water being lifted is in meters (m). For water extraction quality, kg; The acceleration due to gravity is expressed in N / kg. To improve pump efficiency.

[0051] The energy consumption during water conveyance, from an energy consumption perspective, is the head loss along the water conveyance route. Based on the principle of energy conversion, it can be expressed by the following formula: ; ; In the formula, Energy consumption for water conveyance, kW·h; This refers to head loss along the water conveyance route; For water intake weight, kg; Pipe roughness; This refers to the water flow rate. This refers to the water conveyance distance. The diameter is the pipe diameter.

[0052] The energy consumption of the water treatment process, including mixing, flocculation, sedimentation, clarification, and filtration, can be expressed by the following formula: ; In the formula, Energy consumption for the water production process, kW·h. These represent the energy consumption generated during mixing, flocculation, sedimentation, clarification, and filtration, respectively.

[0053] The energy consumption of the wastewater treatment process, including influent, sedimentation, oxygen supply, sludge treatment, and sludge return, can be expressed by the following formula: ; In the formula, Energy consumption for reclaimed water utilization, kW·h These are the energy consumption generated from water intake, sedimentation, oxygen supply, sludge treatment, and sludge return.

[0054] The energy consumption for reclaimed water utilization, including physical coagulation and sedimentation, biological treatment, membrane treatment, and reverse osmosis treatment, can be expressed by the following formula: ; In the formula, Energy consumption for reclaimed water utilization, kW·h These are the energy consumption generated by physical coagulation and sedimentation, biological treatment, membrane treatment, and reverse osmosis treatment, respectively.

[0055] Construct a system dynamics model to calculate the amount of water and carbon reduction achieved in industry.

[0056] The specific operation process includes: Determine the system boundary as follows Figure 2 As shown, the modeling principles are as follows: Figure 3 As shown, the system is divided into two parts: the surface water system and the groundwater system. It includes variables such as surface water saving and groundwater saving, and it is also necessary to determine the time and space boundaries of each element of the system.

[0057] The water-saving and carbon reduction units in this system are in ten thousand tons. The calculation formula for carbon dioxide emissions under different water sources in industrial water systems is used to import these values ​​into the model. Policy influencing factors only represent causal relationships; the degree of impact of relevant policies on reclaimed water utilization and groundwater extraction varies. Figure 4 .

[0058] Construct a variable function relationship. Based on the conversion relationship between water conservation and energy consumption described in step 4, determine that there are 14 relevant variables for both the surface water system and the groundwater system. Among them, the carbon reduction of surface water is a state variable, and the remaining 13 variables are auxiliary variables and constants.

[0059] Energy consumption during water production: ; In the formula, Energy consumption for the water production process, kW·h. The total number of water treatment processes that generate energy consumption is: , For the first Energy consumption of each water production stage.

[0060] Energy consumption during drainage process: ; In the formula, Energy consumption for reclaimed water utilization, kW·h The total number of energy-consuming water reclaimed water production processes is: , For the first Energy consumption in each stage of reclaimed water production.

[0061] Energy consumption for reclaimed water utilization: ; In the formula, Energy consumption for reclaimed water utilization, kW·h The total number of energy-consuming water reclaimed water production processes is: , For the first Energy consumption in each stage of reclaimed water production.

[0062] The construction of the system dynamics model includes determining the system boundary. The system is divided into four main parts: tap water system, surface water system, groundwater system and reclaimed water system. It includes variables such as tap water saving, surface water saving, groundwater saving, and reclaimed water utilization. At the same time, it is necessary to determine the time and space boundaries of each element of the system.

[0063] Constructing a variable function relationship, based on the conversion relationship between water conservation and energy consumption as described in claim 5, it is determined that 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 groundwater system have 14 related variables, of which the carbon reduction of surface water is a state variable, and the remaining 13 variables are auxiliary variables and constants; the reclaimed water system has 6 related variables, of which the carbon increase of reclaimed water is a state variable, and the remaining 5 variables are constants.

[0064] The model simulation calculation determines the proportion of tap water, surface water, groundwater and reclaimed water sources. Based on the water-saving potential calculation results of each industrial sector as described in claim 4, the water-saving amount of surface water and groundwater in each industrial sector is determined. Based on the functional relationship of each system variable, the total amount of industrial water saving and carbon reduction is calculated.

[0065] A brief explanation of variables related to water conservation and carbon reduction (using a region in China as an example);

[0066] A brief explanation of variables related to a tap water system (using a region in China as an example);

[0067] A brief explanation of variables related to the surface water system (using a region in China as an example);

[0068] A brief explanation of variables related to the groundwater system (using a region in China as an example);

[0069] A brief explanation of the variables related to the reclaimed water system (using a region in China as an example);

[0070] Model simulation calculations determine the proportion of surface water and groundwater sources. Based on the water-saving potential calculation results of each industrial sector described in step 3, the water-saving amount of tap water, surface water, and groundwater and the amount of reclaimed water used in each industrial sector are determined. Based on the functional relationship of each system variable, the total amount of industrial water saving and carbon reduction is calculated.

[0071] Existing technologies generally rely on traditional conversion factors when calculating industrial water conservation and carbon reduction. However, this invention considers both the economic attributes of industrial development and the attributes of water resources in the calculation of water conservation potential by industrial sector or the carbon reduction calculation of each water-saving process in the industry. This is more in line with the laws governing industrial water conservation and carbon reduction. By improving the stochastic frontier analysis method to calculate water conservation potential, and on this basis, integrating a system dynamics model, it simulates the energy consumption and carbon emission laws of industrial water resource utilization, thus solving the problem of quantitative calculation of industrial water conservation and carbon emissions, and improving the accuracy of industrial water conservation and carbon reduction potential calculation.

[0072] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this 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. 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. 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 normally distributed. The truncated distribution makes To ensure Follows a normal distribution 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 tests, 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. 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, Potential for water conservation in industry; 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 amount of industrial water-saving and carbon reduction, where the total amount of water-saving and carbon reduction = carbon reduction of tap water + carbon reduction of surface water + carbon reduction of groundwater - carbon increase of reclaimed water. 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; 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: 。 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 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 ; 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 transport ; 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 ; to The energy consumption for each of the mixing, flocculation, sedimentation, clarification, and filtration stages is as follows: Energy consumption during drainage process: ； in, For drainage energy consumption ; 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 ; to The energy consumption is divided into physical coagulation and sedimentation, biological treatment, membrane treatment, and reverse osmosis treatment.

3. The industrial water-saving and carbon reduction calculation method based on stochastic frontier analysis and system dynamics model according to claim 2, 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.

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: 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.

Images