CN-116090831-B - Water quality evaluation method and device based on quantitative classification of non-quantitative indexes of environmental pollution

CN116090831BCN 116090831 BCN116090831 BCN 116090831BCN-116090831-B

Abstract

The application discloses a water quality evaluation method and a device based on quantitative classification of environment pollution non-quantitative indexes, the method comprises screening surface water quality indexes and classifying the surface water quality indexes into direct water quality indexes and indirect water quality indexes, determining an evaluation section and an evaluation period, acquiring water quality concentration original detection data of different times and different sections in the evaluation period, screening a preset number of direct water quality indexes related to the indirect water quality indexes, performing PLSR normalization, calculating an indirect water quality index regression quantitative classification standard one by one, standardizing the original detection data, the direct water quality index national classification standard and the indirect water quality index regression quantitative classification standard into dimensionless values, performing PCA analysis according to the evaluation period and the evaluation section, determining the type of an achieved water quality environment functional area, and obtaining typical water quality indexes of the section according to the PCA analysis.

Inventors

HU YING
WANG DEBAO
LI XIAODAN
ZHAO DANDAN
DU ZHIWEI
PAN SHU
WANG QI

Assignees

中国市政工程东北设计研究总院有限公司

Dates

Publication Date: 20260505
Application Date: 20230221

Claims (10)

1. The water quality evaluation method based on quantitative classification of non-quantitative indicators of environmental pollution is characterized by comprising the following steps: Screening surface water quality indexes and classifying the surface water quality indexes into direct water quality indexes and indirect water quality indexes, wherein the direct water quality indexes refer to indexes which have clear national grading standards and directly evaluate the surface water environment quality pollutant conditions by using a water quality evaluation method, and the indirect water quality indexes refer to indexes which have no clear national grading standards but are closely related to the surface water environment quality conditions; Determining an evaluation section and an evaluation period, and acquiring original detection data of water quality concentration of different times and different sections in the evaluation period; processing the maximum value in the indirect water quality index, and screening a preset number of direct water quality indexes related to the indirect water quality index; Performing PLSR normalization through single indirect water quality indexes and screened concentration original detection data of a preset number of direct water quality indexes, determining and evaluating an environmental functional area of the surface water body and an environmental standard executed by the direct water quality indexes, and calculating the regression quantization grading standard of the indirect water quality indexes one by using a PLSR normalization formula; normalizing the original detection data, the national grading standard of the direct water quality index and the regression, quantization and grading standard of the indirect water quality index into dimensionless values; Carrying out PCA analysis on the standardized direct water quality index and the national grading standard of the direct water quality index, the indirect water quality index and the indirect water quality index regression quantization grading standard according to the evaluation period and the evaluation section, and determining the class of the functional area of the water quality environment according to the PCA comprehensive score ranking sequence of different periods, different sections and the grading standard; and analyzing typical water quality indexes of the section according to the PCA load coefficient obtained by PCA analysis.
2. The method for evaluating the water quality based on quantitative classification of non-quantitative indicators of environmental pollution according to claim 1, wherein the preset number of direct water quality indicators related to the indirect water quality indicators are screened by utilizing characteristic importance functions in a decision tree regression algorithm of the indirect water quality indicators and the direct water quality indicators.
3. The method for evaluating water quality based on quantitative classification of non-quantitative indicators of environmental pollution according to claim 1, wherein the maximum value in the indirect water quality indicator is treated as follows: and calculating a variation coefficient CV value of the indirect water quality index, and when the indirect water quality index which is 3 times higher than the maximum CV value of the direct water quality index is judged to be an abnormal value, and PLSR is performed, changing the abnormal value to an average value in a preset time range before and after the abnormal value.
4. The water quality evaluation method based on quantitative classification of non-quantitative indicators of environmental pollution according to claim 1, wherein the original detection data, the direct water quality indicator classification standard and the indirect water quality indicator regression quantitative classification standard are standardized into dimensionless values by an environmental pollution index method or a mathematical method.
5. The method for evaluating water quality based on quantitative classification of non-quantitative indicators of environmental pollution according to claim 4, wherein the environmental pollution index method is a single-factor standard index method or an internal Mei Luofa.
6. The method for evaluating water quality based on quantitative classification of non-quantitative indicators of environmental pollution according to claim 1, wherein said screening a predetermined number of direct water quality indicators related to indirect water quality indicators comprises: the number of the direct water quality indexes is not less than 3, the importance proportion is continuously selected from large to small according to the characteristics of the direct water quality indexes, and the accumulated importance proportion is not less than 90%.
7. The method for evaluating water quality based on quantitative classification of non-quantitative indicators of environmental pollution according to claim 3, wherein the preset time is two periods before and after.
8. A water quality evaluation device based on quantitative classification of non-quantitative indicators of environmental pollution is characterized by comprising: The screening and classifying unit is used for screening the surface water quality index and classifying the surface water quality index into a direct water quality index and an indirect water quality index, wherein the direct water quality index refers to an index which has a definite national grading standard and is used for directly evaluating the surface water environment quality pollutant condition by using a water quality evaluation method, and the indirect water quality index refers to an index which has no definite national grading standard but is closely related to the surface water environment quality condition; the original detection data acquisition unit is used for determining an evaluation section and an evaluation period and acquiring original detection data of water quality concentration of different times and different sections in the evaluation period; the direct water quality index screening unit is used for processing the maximum value in the indirect water quality indexes and screening the preset number of direct water quality indexes related to the indirect water quality indexes; The PLSR normalization unit is used for performing PLSR normalization through single indirect water quality index and the screened concentration original detection data of the preset number of direct water quality indexes, determining and evaluating the environment standard of the surface water environment functional area and the execution of the direct water quality index, and calculating the regression quantization classification standard of the indirect water quality index one by using a PLSR normalization formula; The standardized unit is used for standardizing the original detection data, the national grading standard of the direct water quality index and the regression, quantization and grading standard of the indirect water quality index into dimensionless values; The water quality environment functional area category determining unit is used for carrying out PCA analysis on the standardized direct water quality index and the direct water quality index national classification standard, the indirect water quality index and the indirect water quality index regression quantization classification standard according to the evaluation period and the evaluation section, and determining the reached water quality environment functional area category according to the PCA comprehensive score ranking sequence of different periods, different sections and classification standards; and the typical water quality index analysis unit is used for analyzing typical water quality indexes of the section according to the PCA load coefficient obtained by PCA analysis.
9. The quantitative classification water quality evaluation device based on non-quantitative indicators of environmental pollution according to claim 8, wherein the direct water quality indicator screening unit is specifically configured to screen a preset number of direct water quality indicators related to the indirect water quality indicators by utilizing a feature importance function in a decision tree regression algorithm of the indirect water quality indicators and the direct water quality indicators.
10. The water quality evaluation device based on quantitative classification of non-quantitative indicators of environmental pollution according to claim 8, wherein, The direct water quality index screening unit is also specifically used for calculating a variation coefficient CV value of an indirect water quality index, and when the indirect water quality index which is 3 times higher than the maximum CV value of the direct water quality index is judged to be an abnormal value, PLSR trend is carried out, the abnormal value is changed into an average value within a preset time range before and after the abnormal value.

Description

Water quality evaluation method and device based on quantitative classification of non-quantitative indexes of environmental pollution Technical Field The invention belongs to the technical field of water quality evaluation, and particularly relates to a water quality evaluation method and device based on quantitative classification of non-quantitative indicators of environmental pollution. Background The surface water evaluation method comprises a single factor evaluation method and a comprehensive factor evaluation method, wherein the single factor evaluation method only can evaluate indexes directly related to the quality condition of the surface water environment, the ratio of each water quality index to the current national surface water environment functional standard is used as an evaluation result, the ratio is larger than 1, the index exceeds the environmental functional area standard, one of the surface water environment indexes exceeds the standard, the water quality section environmental functional area does not reach the standard, the evaluation result of the single factor evaluation method is pessimistic and one-sided, and the relation among a plurality of water quality indexes is not concerned. The comprehensive factor evaluation method is also called multi-factor evaluation method and is mainly divided into two main categories, wherein the first category is characterized in that one or more weight coefficient algorithms are utilized to endow weight coefficients to a plurality of water quality, and finally the water quality is superposed into comprehensive evaluation indexes, wherein the weight coefficient algorithms comprise an entropy value method, a CRITIC weight method, an independent weight coefficient method, a variation coefficient method, a self-defined weight method and the like, the rationality of the weight coefficients needs to be verified through a mathematical test method, the second category is characterized in that each index is standardized firstly, one or more regression algorithms are selected to pass through the internal relation and importance degree among a plurality of indexes, and finally fitting regression is conducted to obtain comprehensive evaluation indexes, the multi-index regression algorithm comprises a least square method, a partial least square method, a mechanical learning method, clustering and the like, the effectiveness of the fitting regression model needs to be verified through the mathematical test method, and the comprehensive evaluation method is used for completing comprehensive evaluation of surface water through comparing the comprehensive evaluation indexes of a plurality of sections in different periods, and can reflect the comprehensive condition of surface water, so that the evaluation result is objective and comprehensive. The water quality index is a series of standards for describing the water quality condition, and the pollution degree of the water body can be judged through some evaluation of the water quality index, and the common water quality index comprises physical indexes including sensory physical indexes such As temperature, chromaticity, turbidity, transparency, flow rate (river), flow rate (lake reservoir capacity) and the like, and other physical water quality indexes such As total solids, suspended solids, fixed solids, conductivity (resistivity), dissolved oxygen, oxidation-reduction potential, chlorophyll a and the like; (2) chemical water quality indicators including organic indicators such As permanganate index (CODmn), chemical oxygen demand (CODcr), five-day biochemical oxygen demand (BOD 5), total Organic Carbon (TOC) and Total Oxygen Demand (TOD), eutrophication indicators such As ammonia nitrogen, kjeldahl nitrogen, nitrite, nitrate, total nitrogen and total phosphorus, inorganic nonmetallic compounds such As total arsenic (As), selenium (Se), fluoride, sulfide, and the like, heavy metals such As mercury (Hg), cadmium (Cd), lead (Pb), chromium (Cr), and the like, toxic and harmful organic matters such As volatile phenol, cyanide, petroleum, anionic surfactants, and the like, and (3) biological water quality indicators including total bacteria count, total coliform count, E.faecalis, and the like. Most chemical indexes, biological indexes and partial physical indexes have clear national grading standards, the quality pollutant condition of the surface water environment can be directly evaluated by using a water quality evaluation method, and the scheme is defined as a direct water quality index (environmental pollution quantitative index). Other physical indexes have perfect detection methods, but have no clear national grading standard, but are still closely related to the quality condition of the surface water environment, and the scheme is defined as an indirect water quality index (an environment pollutant non-quantitative index). In the surface water environment, the direct water quality index and the indirect wat