Method for evaluating eutrophication of water body by using microplankton

Abstract

The invention discloses a method for evaluating eutrophication of a water body by using microplankton, which comprises the following steps: step 1, collecting existing data information, selecting the water body, and selecting permanganate index, total phosphorus, total nitrogen, chlorophyll a and plankton characteristics as evaluation indexes; 2, establishing a principal component analysis method water quality evaluation standard; step 3, carrying out dimensionless treatment on the eutrophication classification standard of the water source in the step 1 by using a standardized treatment method; 4, analyzing the eutrophication of the water body by using a fuzzy comprehensive evaluation method; 5, analyzing the influence of plankton on water eutrophication through correlation analysis; the method has the advantages that water eutrophication is analyzed through water quality evaluation of a principal component analysis method and a fuzzy comprehensive evaluation method, and through correlation analysis of the total number of various types of zooplanktons and physicochemical parameters of effluent, it is obtained that the total number of the zooplanktons is in very remarkable positive correlation with the water temperature and is in remarkable negative correlation with the concentration of NO and-N.

Description

Technical Field

[0001] The invention relates to the technical field of water quality evaluation, in particular to a method for evaluating water eutrophication by utilizing micro-plankton. Background Art

[0002] The control of water eutrophication is a difficult problem faced by the whole world. Due to the lack of environmental protection awareness in human development, the speed at which humans directly or indirectly input nutrients into freshwater bodies far exceeds the self-purification capacity of water bodies. In addition, the domestic water eutrophication evaluation methods are imperfect. Therefore, the existing water eutrophication evaluation methods are not accurate enough for evaluating the eutrophication status of water bodies, or the calculation methods are too complicated and cumbersome, and have no practical application value. As a result, the current domestic water eutrophication methods cannot accurately describe the eutrophication status of water bodies, and provide insufficient basis for water quality improvement for water quality management departments.

[0003] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a method for evaluating the eutrophication of water bodies using micro-plankton.

[0005] In order to solve the above problems, the technical solution of the present invention is a method for evaluating water eutrophication using microplankton, which comprises the following steps:

[0006] Step 1: Collect existing data, select water bodies, and select permanganate index, total phosphorus, total nitrogen, chlorophyll a and plankton characteristics as evaluation indicators;

[0007] Step 2: Establish water quality evaluation standards using principal component analysis;

[0008] Step 3: Use the water source eutrophication classification standard in step 1 of the standardization method to make it dimensionless, use SPSS software to find the correlation coefficient matrix of dimensionless data, and analyze the correlation of eutrophication indicators; Under the premise of good correlation, obtain the eigenvalue of the correlation coefficient matrix and its contribution rate and cumulative contribution rate, so as to analyze and determine the main components; From the main component load value of the eutrophication indicator standard, obtain the eutrophication standard scores at all levels; According to the relationship between the comprehensive main component and the indicators at all levels, refer to the eutrophication grade classification standard to obtain the classification standard of the comprehensive main component of the lake-reservoir type water source;

[0009] Step 4: Analyze the eutrophication of water bodies using fuzzy comprehensive evaluation method;

[0010] Step 5. Analyze the impact of plankton on water eutrophication through correlation analysis.

[0011] Furthermore, the evaluation indicators in step one include heavy eutrophication, rich eutrophication, medium eutrophication, medium eutrophication and oligotrophication, and the evaluation indicators correspond to the permanganate index, total phosphorus, total nitrogen, chlorophyll a and plankton characteristics to obtain numerical values.

[0012] Furthermore, the fuzzy comprehensive evaluation in step 4 is based on the maximum membership principle and the weighted average principle, and includes the following steps: determining the evaluation index of the evaluation object, determining the evaluation level, and dividing the water quality into 5 levels; performing single factor evaluation according to the membership function of the evaluation index, establishing a fuzzy relationship matrix, and obtaining the membership function of 5 levels according to the 5-level standard of each index; determining the fuzzy weight vector of the evaluation index; using fuzzy operation to obtain the fuzzy comprehensive evaluation result vector, and analyzing the result of the fuzzy comprehensive evaluation.

[0013] Furthermore, the water quality evaluation by principal component analysis in step 2 includes the following steps: establishing an original variable matrix, standardizing the original variable matrix, calculating the correlation coefficient and characteristics of the standardized matrix, determining the number of principal components, determining the expression of the main components, determining the comprehensive evaluation function, and calculating the principal component scores.

[0014] Furthermore, the number of plankton N=(counting volume*number of individuals obtained by counting) / sampling volume*sedimentation volume.

[0015] Furthermore, the correlation analysis in step 5 analyzes the community characteristics of zooplankton in the biological grid, and the total number of zooplankton is very significantly positively correlated with water temperature, and the total number of zooplankton is significantly negatively correlated with NO,-N concentration.

[0016] The advantages of the present invention compared with the prior art are:

[0017] 1. The present invention uses the principal component analysis method to evaluate water quality and the fuzzy comprehensive evaluation method to analyze the eutrophication of water bodies. Through the correlation analysis between the total number of zooplankton species and the physical and chemical parameters of the effluent, it is concluded that the total number of zooplankton species is very significantly positively correlated with the water temperature, and is significantly negatively correlated with the concentration of NO,-N; the total number of creeping ciliates is significantly negatively correlated with the concentrations of NO,-N and NO:-N; the concentration of NO:-N is significantly and very significantly positively correlated with the total number of swimming ciliates and fixed ciliates, respectively; the concentration of COD. is significantly positively correlated with the total number of swimming ciliates and is significantly negatively correlated with the total number of fixed ciliates. DETAILED DESCRIPTION

[0018] In order to make the contents of the present invention more clearly understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention.

[0019] A method for evaluating water eutrophication using microplankton comprises the following steps:

[0020] Step 1: Collect existing data, select water bodies, and select permanganate index, total phosphorus, total nitrogen, chlorophyll a and plankton characteristics as evaluation indicators;

[0021] Step 2: Establish water quality evaluation standards using principal component analysis;

[0022] Step 3: Use the water source eutrophication classification standard in step 1 of the standardization method to make it dimensionless, use SPSS software to find the correlation coefficient matrix of dimensionless data, and analyze the correlation of eutrophication indicators; Under the premise of good correlation, obtain the eigenvalue of the correlation coefficient matrix and its contribution rate and cumulative contribution rate, so as to analyze and determine the main components; From the main component load value of the eutrophication indicator standard, obtain the eutrophication standard scores at all levels; According to the relationship between the comprehensive main component and the indicators at all levels, refer to the eutrophication grade classification standard to obtain the classification standard of the comprehensive main component of the lake-reservoir type water source;

[0023] Step 4: Analyze the eutrophication of water bodies using fuzzy comprehensive evaluation method;

[0024] Step 5. Analyze the impact of plankton on water eutrophication through correlation analysis.

[0025] The evaluation indicators in step one include heavy eutrophication, rich eutrophication, medium eutrophication, medium eutrophication and oligotrophication, and the evaluation indicators correspond to the permanganate index, total phosphorus, total nitrogen, chlorophyll a and plankton characteristics to obtain numerical values.

[0026] The fuzzy comprehensive evaluation in step four is based on the maximum membership principle and the weighted average principle, and includes the following steps: determine the evaluation index of the evaluation object, determine the evaluation level, and divide the water quality into 5 levels; conduct single factor evaluation based on the membership function of the evaluation index, establish a fuzzy relationship matrix, and calculate the membership function of 5 levels based on the 5-level standard of each index; determine the fuzzy weight vector of the evaluation index; use fuzzy operation to obtain the fuzzy comprehensive evaluation result vector, and analyze the results of the fuzzy comprehensive evaluation.

[0027] The water quality evaluation by principal component analysis in step 2 includes the following steps: establishing the original variable matrix, standardizing the original variable matrix, calculating the correlation coefficient and characteristics of the standardized matrix, determining the number of principal components, determining the expression of the main components, determining the comprehensive evaluation function, and calculating the principal component scores.

[0028] The number of plankton N = (counting volume * number of individuals counted) / sampling volume * sedimentation volume.

[0029] In step 5, the correlation analysis analyzed the community characteristics of zooplankton in the biological grid. The total number of zooplankton species was significantly positively correlated with water temperature, indicating that temperature has an extremely important influence on the number of zooplankton species and is its limiting factor; while the total number of species was significantly negatively correlated with the concentration of NO, -N, indicating that the total number of species is not the main limiting factor affecting the increase in NO, -N concentration. The total number of creeping ciliates was significantly negatively correlated with the concentrations of NO:-N and NO:-N, indicating that the changes in their number of species and abundance have a very obvious indicative effect on the nitrification function of the system. The concentration of NO:-N was significantly and very significantly positively correlated with the total number of swimming ciliates and fixed ciliates, respectively, indicating that the total number of the two has an important regulatory effect on the concentration of NO, -N. The concentration of COD. was significantly positively correlated with the total number of swimming ciliates and significantly negatively correlated with the total number of fixed ciliates. Therefore, the change in COD concentration was significantly affected by the total number of swimming ciliates and decreased significantly with the increase in the total number of fixed ciliates. The total number of other zooplankton groups in the system has a certain correlation with various physical and chemical parameters of the effluent water quality, but it is not obvious.

[0030] The present invention and its implementation methods are described above, but such description is not restrictive, and what is shown is only one of the implementation methods of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A method for evaluating water eutrophication using microplankton, characterized in that: The following steps are involved: Step 1: Collect existing data, select water bodies, and select permanganate index, total phosphorus, total nitrogen, chlorophyll a and plankton characteristics as evaluation indicators; Step 2: Establish water quality evaluation standards using principal component analysis; Step 3: Use the water source eutrophication classification standard in step 1 of the standardization method to make it dimensionless, use SPSS software to find the correlation coefficient matrix of dimensionless data, and analyze the correlation of eutrophication indicators; Under the premise of good correlation, obtain the eigenvalue of the correlation coefficient matrix and its contribution rate and cumulative contribution rate, so as to analyze and determine the main components; From the main component load value of the eutrophication indicator standard, obtain the eutrophication standard scores at all levels; According to the relationship between the comprehensive main component and the indicators at all levels, refer to the eutrophication grade classification standard to obtain the classification standard of the comprehensive main component of the lake-reservoir type water source; Step 4: Analyze the eutrophication of water bodies using fuzzy comprehensive evaluation method; Step 5. Analyze the impact of plankton on water eutrophication through correlation analysis.

2. The method for evaluating water eutrophication using microplankton according to claim 1, characterized in that: The evaluation indicators in step one include heavy eutrophication, eutrophication, medium eutrophication, medium eutrophication and oligotrophication, and the evaluation indicators correspond to the permanganate index, total phosphorus, total nitrogen, chlorophyll a and plankton characteristics to obtain numerical values.

3. The method for evaluating water eutrophication using microplankton according to claim 1, characterized in that: The fuzzy comprehensive evaluation in step 4 is based on the maximum membership principle and the weighted average principle, and includes the following steps: determining the evaluation index of the evaluation object, determining the evaluation level, and dividing the water quality into 5 levels; performing single factor evaluation according to the membership function of the evaluation index, establishing a fuzzy relationship matrix, and obtaining the membership function of 5 levels according to the 5-level standard of each index; determining the fuzzy weight vector of the evaluation index; using fuzzy operation to obtain the fuzzy comprehensive evaluation result vector, and analyzing the result of the fuzzy comprehensive evaluation.

4. The method for evaluating water eutrophication using microplankton according to claim 1, characterized in that: The water quality evaluation using the principal component analysis method in step 2 includes the following steps: establishing an original variable matrix, standardizing the original variable matrix, calculating the correlation coefficient and characteristics of the standardized matrix, determining the number of principal components, determining the expression of the main components, determining a comprehensive evaluation function, and calculating the principal component scores.

5. The method for evaluating water eutrophication using microplankton according to claim 1, characterized in that: The number of plankton N=(counting volume*number of individuals obtained by counting) / sampling volume*sedimentation volume.

6. The method for evaluating water eutrophication using microplankton according to claim 1, characterized in that: The correlation analysis in step 5 analyzes the community characteristics of zooplankton in the biological grid, and the total number of zooplankton is very significantly positively correlated with water temperature, and the total number of zooplankton is significantly negatively correlated with NO,-N concentration.