Pollution source emission limit value determination method based on offshore area eutrophication control

Abstract

The invention provides a pollution source emission limit value determination method based on offshore area eutrophication control, which comprises the following steps: respectively calculating a pollutant maximum allowable emission amount based on a drainage basin water quality target and a pollutant maximum allowable emission amount based on a sea area water quality target; determining the minimum value of the maximum allowable discharge amount of the pollutants as the maximum allowable discharge amount of the drainage basin; constructing a drainage basin water quality model according to the maximum allowable drainage volume of the drainage basin, and simulating different emission reduction scenes of different pollution sources according to the drainage basin water quality model; judging whether the pollutant discharge amount of the drainage basin is smaller than the maximum allowable discharge amount of the drainage basin or not, and if yes, determining the discharge limit value of a target pollution source by using a technology-based industry discharge limit value determination method; and if not, determining the emission limit value of the target pollution source by using a water quality-based emission limit value determination method. The emission limit value determination technology based on the offshore area eutrophication control target provided by the invention has great significance for perfecting an original emission limit value determination technology system.

Description

Technical Field

[0001] The present invention relates to the technical field of water environment protection and environmental management, and in particular to a method for determining emission limits of pollution sources based on eutrophication control in nearshore waters. Background Art

[0002] Rivers entering the sea are the main source of nitrogen and phosphorus input to coastal waters. Controlling the nitrogen and phosphorus emissions and concentrations from land-based pollution sources in rivers entering the sea is of great significance for controlling eutrophication in coastal waters. Based on the eutrophication control targets in the sea area, the technology for determining the emission limits of total nitrogen and total phosphorus for regions, river basins and key industries is proposed, which can provide effective scientific and technological support for the control of land-based pollution in coastal waters and the management of eutrophication in the sea area.

[0005] China's emission limit determination technology includes technology-based emission limit determination and total amount constraint and allocation-based emission limit determination technology. The technology-based emission limit determination method is mainly based on existing emission standards, technical guidelines, clean production evaluation system and other technologies, and combines the actual production and pollution discharge conditions of enterprises to determine the emission limit method. The starting point is the technical level that enterprises can achieve at this stage. The emission limit determination technology based on total amount constraint and allocation is similar to the technical method of the US EPA, but at this stage there is still no emission limit determination technology based on the eutrophication control target of nearshore waters, and the existing technical means for determining emission limits are still not truly based on the response relationship between pollution sources and water quality. Summary of the invention

[0006] In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a method for determining emission limits of pollution sources based on eutrophication control in nearshore waters, which is of great significance for improving the original emission limit determination technology system.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A method for determining emission limits of pollution sources based on eutrophication control in coastal waters, comprising:

[0009] Calculate the maximum allowable pollutant discharge based on the water quality target of the river basin and the maximum allowable pollutant discharge based on the water quality target of the sea area respectively, and determine the minimum value of the maximum allowable pollutant discharge as the maximum allowable discharge to the sea of ​​the river basin;

[0010] constructing a water quality model for the watershed according to the maximum allowable discharge volume of the watershed, and simulating different emission reduction scenarios for different pollution sources based on the water quality model for the watershed;

[0011] When judging whether the pollutant emissions of a river basin are less than the maximum allowable discharge into the sea of ​​the river basin, if so, the emission limits of target pollution sources are determined using a technology-based industry emission limit determination method; if not, the emission limits of target pollution sources are determined using a water quality-based emission limit determination method.

[0012] Preferably, the calculation formula for the maximum allowable pollutant discharge based on the watershed water quality target is:

[0013]

[0014] X j ≥0;

[0015] In the formula, X j is the emission of the jth pollution source, a ij ′ is the pollutant concentration addition of the ith pollution source to the ith control section, C i is the water quality target of the ith control section, C 0i is the background water quality of the ith control section, m is the total number of control sections, and MAPR is the maximum allowable discharge of the basin based on the basin water quality target.

[0016] Preferably, the calculation formula for the maximum allowable pollutant discharge based on the marine water quality target is:

[0017] MAPC=max∑ j F j ;

[0018]

[0019] F j ≥0;

[0020] α ij =p i,j / ∑ j p i,j ;

[0021] Among them, F j is the pollutant load emitted by the jth pollution source, n is the number of pollution sources, is the background water quality at the i-th location on the coast, is the national seawater quality standard at the i-th location on the coast, m is the number of water quality control points, α ij is the contribution parameter of the j-th pollution source unit emission to the change of pollutant concentration at the i-th water quality control point, p i,j is the response parameter of the ith pollution source to the jth water quality point, and MAPC is the maximum allowable discharge of the basin based on the offshore water quality target.

[0022] Preferably, the technology-based method for determining industry emission limits includes:

[0023] Four types of pollutant emission load limits are introduced for pollutant management periods in different statistical cycles; the pollutant emission load limits include maximum daily emission load MDL, weekly average daily emission load AWL, monthly average daily emission AML and long-term annual average daily emission load LTA; the calculation formula for the pollutant emission load limit is:

[0024] Where X i is the daily pollutant emission concentration of the pollution source, mg / L, n is the sample size of the monitoring data, z is the standard score, and the z value corresponding to 95% of the normal distribution of the data is taken in the calculation, which is 1.65; CV is the coefficient of variation of the sample data, and c is the sample statistical period, usually 1 day, 7 days and 30 days;

[0025] According to the formula Determine the concentration emission limit values ​​for different statistical periods; where C pi is the concentration emission limit value for the i-th period, L i represents the pollutant emission load target, Q i Represents the wastewater discharge in different time periods i, i=1-4, 1-4 represent LTA, AWL, AML and MDL respectively.

[0026] Preferably, the formula for determining the discharge limit based on water quality is:

[0027]

[0028] In the formula, C pi is the concentration emission limit value for the i-th period, L i represents the pollutant emission load target, Q i It represents the wastewater discharge in different time periods i, i=1-4, 1-4 represent LTA, AWL, AML and MDL respectively, and p is the emission reduction ratio of various pollution sources.

[0029] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0030] The present invention provides a method for determining emission limits of pollution sources based on eutrophication control in nearshore waters, including: respectively calculating the maximum allowable pollutant emissions based on the water quality target of the river basin and the maximum allowable pollutant emissions based on the water quality target of the sea area, and determining the minimum value of the maximum allowable pollutant emissions as the maximum allowable discharge to the sea in the river basin; constructing a river basin water quality model according to the maximum allowable discharge to the sea in the river basin, and simulating different emission reduction scenarios of different pollution sources according to the river basin water quality model; judging whether the pollutant emissions of the river basin are less than the maximum allowable discharge to the sea in the river basin, if so, determining the emission limit of the target pollution source using the industry emission limit determination method based on technology; if not, determining the emission limit of the target pollution source using the emission limit determination method based on water quality. The emission limit determination technology based on the eutrophication control target of nearshore waters proposed by the present invention is of great significance for improving the original emission limit determination technology system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 A flow chart of a method provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of a technical route provided for an embodiment of the present invention. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Figure 1 A flow chart of a method provided by an embodiment of the present invention, such as Figure 1 As shown, the present invention provides a method for determining emission limits of pollution sources based on eutrophication control in nearshore waters, comprising:

[0037] Step 100: Calculate the maximum allowable pollutant discharge based on the water quality target of the river basin and the maximum allowable pollutant discharge based on the sea water quality target, and determine the minimum value of the maximum allowable pollutant discharge as the maximum allowable discharge to the sea of ​​the river basin;

[0038] Step 200: constructing a water quality model for the watershed according to the maximum allowable discharge volume of the watershed, and simulating different emission reduction scenarios for different pollution sources according to the water quality model for the watershed;

[0039] Step 300: Determine whether the pollutant emission of the basin is less than the maximum allowable discharge into the sea of ​​the basin. If so, use a technology-based industry emission limit determination method to determine the emission limit of the target pollution source; if not, use a water quality-based emission limit determination method to determine the emission limit of the target pollution source.

[0040] like Figure 2 As shown, this embodiment first clarifies the contribution of land, sea and air pollution sources to nitrogen and phosphorus pollution in coastal waters, constructs the response relationship between land, sea and air pollution sources and sea water quality, takes the key water quality factor control targets for eutrophication control in coastal waters and the background value of sea water quality as constraints, uses linear programming or nonlinear programming methods to determine the maximum allowable emissions of different pollution sources, and then takes the maximum allowable emissions of land pollution sources as constraints. According to the three aspects of economy, fairness and efficiency, the allocation principles and proportions of allowable emissions from land are constructed, and finally the step-by-step optimization allocation of allowable emissions from land sources from river basins to regions to pollution sources is achieved, and nitrogen and phosphorus emission limits based on coastal waters water quality targets are proposed.

[0041] (1) Relationship between river basin pollution sources and estuary nitrogen and phosphorus pollution fluxes

[0042] Construct a watershed water quality model to establish the relationship between pollution sources and nitrogen and phosphorus output fluxes at the estuary:

[0043] L outi =(L point，i +L diff，i )(1-RivR i )

[0044]

[0045] Where RivR i Pollutant retention rate in the i-level river, dimensionless, V f Infinite is the removal rate of nutrients in the river-reservoir system, m·a -1 The reference value of the river channel is 17.5-44.5m·a -1 The reference value of the reservoir is 3.92-11.7m·a-1, H L is the hydraulic load (m·a-1), L point，iis the point source load into the river in the i-level river control basin, t / a, L diff，i It is the surface source load into the river in the controlled basin of level i river, t / a.

[0046] (2) Relationship between rivers entering the sea and coastal water quality

[0047]

[0048] In the formula, f(x, y, t) is the emission intensity of the pollution source, gs -1 , c is the pollutant concentration, mg / L, α(x, y, t) is the lateral flow velocity, ms -1 , β(x, y, t) is the longitudinal velocity, ms -1 , D x (x, y, t) is the lateral diffusion coefficient, D y (x, y, t) is the longitudinal diffusion coefficient, x, y are the x- and y-coordinates of the Cartesian coordinate system, m.

[0049] (3) The conversion formula between river water quality targets and ocean water quality targets is as follows:

[0050]

[0051] In the formula, θ is the conversion coefficient between river water quality target and ocean water quality target, m is the number of points, n is the length of the time series, and C i，m is the ocean water quality target of the ith pollutant corresponding to the mth point, C j，m is the river water quality target of the jth pollutant corresponding to the mth point.

[0052] (4) Consider the economics, fairness and benefits of pollution source reduction

[0053] 1) Marginal emission reduction cost curve fitting

[0054] Fitting the marginal emission reduction cost curve of fixed sources, the marginal emission reduction cost curve may follow a linear or nonlinear change law, and its relationship with the marginal emission reduction cost is:

[0055]

[0056] In the formula, E i is the marginal reduction cost of annual pollutant load of the jth stationary source within the i-scale, RMB 10,000 / t, M i,j and L i,j is the annual operating cost (10,000 yuan) and annual pollutant load reduction of the jth stationary source within the i scale, t / a. The marginal emission reduction curves a and b are fitting parameters. At a reasonable confidence level, the optimal fitting result is selected as the corresponding fitting method.

[0057] 2) Optimization methods for pollution reduction schemes considering economy, fairness and efficiency

[0058] Based on the marginal emission reduction cost curve, under the premise of achieving the overall reduction target, the new load reduction amount of fixed pollution sources is calculated using the nonlinear programming method under the condition of minimum emission reduction cost Q:

[0059]

[0060] Where Q is the cost of achieving the overall reduction target, RMB 10,000, n is the number of fixed pollution sources, L is i is the annual average pollutant load reduction of the i-stationary pollution source, t, x i is the additional load reduction of i fixed pollution sources, t, L Total is the total amount of pollutant load reduction, t, L ul,i The 5% quantile of pollutant reduction load for stationary sources.

[0061] The relationship between land-based pollution sources and the water quality response of the sections of rivers entering the sea is constructed, the spatiotemporal variation characteristics of nitrogen and phosphorus fluxes into the sea in river basins entering the sea are described, the risk areas and time periods for nitrogen and phosphorus entering the sea are identified, and different emission scenarios for key pollution sources are simulated. The emission scenarios that meet the maximum allowable discharge into the sea in the basin are used as the emission limits for key pollution sources. Based on the sewage discharge characteristics of key pollution sources, the emission concentration limits of nitrogen and phosphorus pollutants in basins, regions and key industries are finally calculated.

[0062] Specifically, the steps for determining the maximum allowable sea discharge volume in this embodiment are as follows:

[0063] At the same time, calculate the maximum allowable pollutant emissions based on the water quality targets of the river basin and the maximum allowable pollutant emissions based on the sea area water quality targets, and take the smaller value as the maximum allowable discharge into the sea of ​​the river basin.

[0064] (1) Calculation of maximum allowable pollutant emissions based on water quality targets

[0065]

[0066] X j ≥0(equ.3)

[0067] In the formula, X j is the emission of the jth pollution source, a ij is the pollutant concentration addition of the ith pollution source to the ith control section. i is the water quality target of the ith control section. 0i is the background water quality of the ith control section.

[0068] (2) Calculation of maximum allowable pollutant emissions based on marine water quality targets

[0069] MAPC=max∑ j F j (equ.4)

[0070]

[0071] F j ≥0(equ.6)

[0072] α ij =p i,j / ∑ j p i,j (equ.7)

[0073] In the formula, F j is the pollutant load emitted by the jth pollution source, n is the number of pollution sources, is the background water quality at the i-th location on the coast. In this study, the background concentrations of dissolved inorganic nitrogen (DIN) and soluble reactive phosphorus (SRP) were 0.2 mg / L and 0.01 mg / L, respectively. is the national seawater quality standard at the i-th location on the coast, and m is the number of water quality control points. ij It is the contribution parameter of the unit emission of the jth pollution source to the change of pollutant concentration at the i-th water quality control point. i,j is the response parameter of the i-th pollution source to the j-th water quality point.

[0074] Furthermore, the method for analyzing the reduction of pollution sources based on the watershed water quality model scenario simulation in this embodiment is as follows:

[0075] The watershed water quality model can simulate different emission reduction scenarios for different pollution sources. Table 1 shows the settings of emission reduction scenarios for different pollution sources. Due to the influence of climatic conditions, the wastewater generated by non-point source pollution is diffusive and random, so it is difficult to accurately estimate the emission limits of non-point sources. However, the task of reducing pollution loads should also be assigned to non-point source pollution. The watershed water quality model can simulate the reduction effects of different farmland management measures, including fertilizer management and crop rotation system management, buffer zone management measures, etc. on non-point source pollution loads. After reducing the pollutant load that may be generated by non-point source pollution, the goal of reducing emissions can be achieved by adjusting the emissions of point sources in the watershed model.

[0076] Table 1 Analysis of reduction scenarios for different pollution sources in the water quality model

[0077]

[0078] Furthermore, the steps for determining the industry pollutant emission limits based on the water quality targets of the river basin and sea area in this embodiment are as follows:

[0079] When the pollutant discharge in the basin is less than the allowable discharge into the sea, the technology-based industry emission limit is used. Otherwise, the water quality-based emission limit determination method is used.

[0080] (1) Emission limits based on technology

[0081] This study introduces four pollutant emission load limits for pollutant management periods in different statistical periods, including maximum daily emission load (MDL), weekly average daily emission load (AWL), monthly average daily emission (AML) and long-term annual average daily emission load (LTA), which are calculated through equations 9 to 13. LTA is basically obtained from the long-term average daily emission data achieved by unit products, and is studied through emission standards or pollution survey emission coefficients. If the emission data is sufficient, LAT can be calculated through equation 8.

[0082]

[0083] The concentration emission limits for different statistical periods are determined by the following formula.

[0084]

[0085] In the formula, C pi is the concentration emission limit value for the i-th period, mg / L. i Indicates the pollutant emission load target, kg. Q i Indicates the wastewater discharge in different time periods i, kg. i = 1-4, 1-4 represents LTA, AWL, AML and MDL.

[0086] (2) Emission limits based on water quality constraints

[0087]

[0088] After scenario analysis, the emission reduction ratio p of each pollution source can be obtained, thereby obtaining the pollutant emission limit based on water quality constraints.

[0089] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0090] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for determining emission limits of pollution sources based on eutrophication control in coastal waters, characterized in that: include: Calculate the maximum allowable pollutant discharge based on the water quality target of the river basin and the maximum allowable pollutant discharge based on the water quality target of the sea area respectively, and determine the minimum value of the maximum allowable pollutant discharge as the maximum allowable discharge to the sea of ​​the river basin; constructing a water quality model for the watershed according to the maximum allowable discharge volume of the watershed, and simulating different emission reduction scenarios for different pollution sources based on the water quality model for the watershed; When judging whether the pollutant emissions of a river basin are less than the maximum allowable discharge into the sea of ​​the river basin, if so, the emission limits of target pollution sources are determined using a technology-based industry emission limit determination method; if not, the emission limits of target pollution sources are determined using a water quality-based emission limit determination method.

2. The method for determining emission limits of pollution sources based on eutrophication control in coastal waters according to claim 1 is characterized in that: The calculation formula for the maximum allowable pollutant discharge based on the watershed water quality target is: X j ≥0； Where, X j is the emission of the jth pollution source, a ij ′ is the pollutant concentration addition of the ith pollution source to the ith control section, C i is the water quality target of the ith control section, C 0i is the background water quality of the ith control section, m is the total number of control sections, and MAPR is the maximum allowable discharge of the basin based on the basin water quality objectives.

3. The method for determining emission limits of pollution sources based on eutrophication control in coastal waters according to claim 1 is characterized in that: The calculation formula for the maximum allowable pollutant discharge based on the marine water quality target is: MAPC=max∑ j F j ; F j ≥0； a ij =p i，j / ∑ j p i，j ; Among them, F j is the pollutant load emitted by the jth pollution source, n is the number of pollution sources, is the background water quality at the i-th location on the coast, is the national seawater quality standard at the i-th location on the coast, m is the number of water quality control points, α ij is the contribution parameter of the unit emission of the ith pollution source to the change of pollutant concentration at the ith water quality control point, p i j is the response parameter of the ith pollution source to the ith water quality point, and MAPC is the maximum allowable discharge of the basin based on the nearshore water quality target.

4. The method for determining emission limits of pollution sources based on eutrophication control in coastal waters according to claim 1 is characterized in that: Technology-based methodologies for determining industry emission limits include: Four types of pollutant emission load limits are introduced for pollutant management periods in different statistical cycles; the pollutant emission load limits include maximum daily emission load MDL, weekly average daily emission load AWL, monthly average daily emission AML and long-term annual average daily emission load LTA; the calculation formula for the pollutant emission load limit is: Among them, X i is the daily pollutant emission concentration of the pollution source, n is the sample size of the monitoring data, z is the standard score; CV is the coefficient of variation of the sample data, and c is the sample statistical period; According to the formula Determine the concentration emission limit values ​​for different statistical periods; where Cpi is the concentration emission limit value for the i-th period, L i represents the pollutant emission load target, Q i Represents the wastewater discharge in different time periods i, i=1-4, 1-4 represent LTA, AWL, AML and MDL respectively.

5. The method for determining emission limits of pollution sources based on eutrophication control in coastal waters according to claim 1 is characterized in that: The formula for determining the discharge limit based on water quality is: In the formula, C pi is the concentration emission limit value for the i-th period, L i represents the pollutant emission load target, Q i It represents the wastewater discharge in different time periods i, i=1-4, 1-4 represent LTA, AWL, AML and MDL respectively, and p is the emission reduction ratio of various pollution sources.

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