Overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm

Abstract

The invention discloses an overflow sewage coagulation-oxidation treatment method based on support vector regression and a particle swarm optimization algorithm, which belongs to the technical field of sewage treatment methods, and comprises the following steps: selecting an optimal treatment method of overflow sewage from a plurality of sewage treatment agent adding modes; respectively measuring the effluent pollutant concentration under the influence of a single characteristic variable, and constructing an effluent quality index (WQI) prediction model based on the pollutant concentration. According to the method, synergistic removal of various pollutants is comprehensively considered, and coupling process parameters of sodium hypochlorite (NaClO) oxidation and polyaluminum chloride (PACl) coagulation are optimized by utilizing support vector regression (SVR) and a particle swarm optimization (PSO) algorithm, so that the treatment effect of urban overflow sewage can be effectively improved, and the safety and sustainable development of a water environment are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment methods, and in particular to an overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm. Background Art

[0002] At present, there is a common problem of rainwater and sewage mixing in urban drainage pipes, which leads to increased load on the drainage network during heavy rain or continuous rainfall, which is prone to overflow of rainwater and sewage. Overflow sewage has pollution characteristics such as multi-source, multi-state, and impact. Among them, high concentrations of ammonia nitrogen (NH3-N), chemical oxygen demand (COD), total nitrogen (TN), organic matter, total phosphorus (TP) and suspended solids (SS) and other pollutants, if discharged directly without treatment, will seriously pollute the receiving water body, threatening the balance of the water ecosystem and the safety of residents' drinking water.

[0003] Effectively controlling overflow pollution has become an urgent need to improve urban sustainable development, and the development of effective end-of-pipe treatment technologies is crucial to improving urban water environment quality.

[0004] The Chinese invention patent with publication number CN119294612A provides a method and system for predicting parameters of sewage treatment plants based on machine learning, which shows significant advantages in predicting key operating parameters of sewage treatment plants. However, overflow sewage has impact pollution characteristics, making it difficult to directly apply the processes applicable in sewage treatment plants to the treatment of overflow sewage. In addition, research on machine learning algorithms in optimizing overflow treatment process parameters is still relatively limited, making it difficult to effectively improve the efficiency and water quality of sewage treatment. Summary of the invention

[0005] The purpose of the present invention is to provide a coagulation-oxidation treatment method for overflow sewage based on support vector regression and particle swarm optimization algorithm, which can effectively improve the treatment effect of urban overflow sewage by comprehensively considering the synergistic removal of multiple pollutants and optimizing the coupling process parameters of sodium hypochlorite (NaClO) oxidation and polyaluminium chloride (PACl) coagulation by using support vector regression (SVR) and particle swarm optimization algorithm (PSO).

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for coagulation-oxidation treatment of overflow sewage based on support vector regression and particle swarm optimization algorithm, the method is used to control the concentration of pollutants in overflow sewage, the method comprising: Selecting the optimal treatment method for overflow sewage from a variety of sewage treatment agent addition methods can achieve pretreatment of overflow sewage, and through correlation analysis of various characteristic variables affecting effluent water quality, and using standardization methods to eliminate dimensional differences, improve the convergence speed of the model; Under the conditions of the optimal treatment method, the concentration of effluent pollutants under the influence of a single characteristic variable is measured respectively, and the treatment effect is judged based on the correlation between the concentration of pollutants and the degree of water cleanliness; A prediction model for effluent water quality index (WQI) was constructed based on pollutant concentrations.

[0007] As a further embodiment of the present invention: Preferably, the pollutants are SS, COD, TN, NH3-N and TP, and the overflow sewage from the sewage pipe is taken, and its water quality characteristics are: SS = 396 mg / L, NH3-N = 21.14 mg / L, TN = 22.52 mg / L, COD = 302.5 mg / L, TP = 1.32 mg / L, pH = 8.1 and water temperature = 25 °C.

[0008] As a further solution of the present invention: the method of selecting the optimal treatment method for overflow sewage from a variety of sewage treatment agent addition methods includes: The overflow sewage to be treated is placed in a reaction container, and sewage treatment agents are added to the reaction container in a certain order to separate the overflow sewage into layers; Calculate the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage; All result data are compared pairwise, and the result data corresponding to the smallest water quality index (WQI) is selected as the optimal result data. The processing method that obtains the optimal result data is used as the optimal treatment method. By comparing and analyzing the effects of different reagent addition sequences on the overflow sewage treatment results, the optimal reagent addition sequence and reagent treatment method can be quickly determined, which is beneficial to improving the water treatment effect and efficiency of overflow sewage.

[0009] As a further solution of the present invention: the first water treatment agent is a coagulant. By using a coagulant as the first water treatment agent, the tiny particles in the sewage can be aggregated into flocs through chemical or physical effects, which is convenient for subsequent precipitation and filtration treatment. The second water treatment agent is an oxidant. The oxidant can oxidize the COD in the sewage, which is beneficial to remove organic matter in the sewage through oxidation, improve the odor in the sewage, and reduce the color of the sewage by oxidizing the organic pigments in the sewage.

[0010] As a further solution of the present invention: the coagulant is a polyaluminium chloride (PACl) solution, the concentration of the polyaluminium chloride (PACl) solution is 250 mg / L, and the oxidant is a sodium hypochlorite (NaClO) solution, the concentration of the sodium hypochlorite (NaClO) solution is 200 mg / L.

[0011] As a further solution of the present invention: the method for calculating the water quality index (WQI) of overflow sewage to obtain result data of overflow sewage includes: The pollution index calculation formula is used Calculate the water pollution index, where i is the type of pollutant; I i is the water pollution index of pollutant i; C i is the concentration of pollutant i; S i It is the evaluation standard of pollutant i. The evaluation standard of single indicator refers to the three-level standard in the national standard "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB 18918-2002) in water. The smaller the WQI value, the higher the degree of water cleanliness.

[0012] As a further solution of the present invention: the method of adding sewage treatment agents to the reaction container in a certain order comprises: Adding a first water treatment agent and a second water treatment agent simultaneously into a first reaction container to obtain a first solution; forming a synchronous coagulation-oxidation treatment method; The method for stratifying overflow sewage comprises: After stirring the first solution at a speed of 250 r / min for 30 seconds, the first solution was stirred at a speed of 50 r / min for 4 to 5 minutes; The stirred first solution was allowed to settle for 5 minutes to obtain a first layered solution; The method for calculating the water quality index (WQI) of overflow sewage to obtain the result data of overflow sewage includes: Measuring the pollutant concentration value in the first layer solution; Based on the pollutant concentration, the water quality index (WQI) of the first layered solution is calculated using the pollution index calculation formula, and a first pollution index is obtained according to the calculation result.

[0013] As a further solution of the present invention: the method of adding sewage treatment agents to the reaction container in a certain order to stratify the overflow sewage also includes: Adding the first water treatment agent into the second reaction container to obtain a second solution, forming a pre-coagulation-oxidation treatment method, stirring the second solution at a speed of 250 r / min for 1 minute, and allowing the second solution to stand for 5 minutes after the stirring is completed; Adding a second water treatment agent to the second solution after standing, stirring the second solution with the second water treatment agent added at a speed of 100 r / min for 5 minutes, and after the stirring is completed, standing the second solution for 5 minutes to obtain a second layered solution; The method for calculating the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage also includes: measuring the concentration of pollutants in the second layer solution; Based on the pollutant concentration, the water quality index (WQI) of the second layered solution is calculated using the pollution index calculation formula, and a second pollution index is obtained according to the calculation result.

[0014] As a further solution of the present invention: the method of adding sewage treatment agents to the reaction container in a certain order to stratify the overflow sewage also includes: Adding the second water treatment agent into the third reaction container to obtain a third solution, stirring the third solution at a speed of 50 r / min for 5 minutes, and adding the first water treatment agent to the stirred third solution; forming a pre-oxidation-coagulation treatment method; After stirring at 250 r / min for 1 min, the mixture was allowed to settle for 5 min to obtain the third layer solution; The method for calculating the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage also includes: measuring the concentration of pollutants in the third layer solution; Based on the pollutant concentration, the water quality index (WQI) of the third layered solution is calculated using the pollution index calculation formula, and a third pollution index is obtained according to the calculation result.

[0015] As a further solution of the present invention: the single characteristic variable includes: any one of the factors of coagulant concentration value, oxidant concentration value, coagulation time, oxidation time, pH value, water temperature value and influent water quality data value. By introducing characteristic variables including pH value, water temperature value and influent water quality, it is beneficial to increase the breadth of characteristic variables to improve the prediction accuracy of the model; The method for measuring the concentration of effluent pollutants under the influence of a single characteristic variable under the condition of the optimal treatment method includes: According to the optimal treatment method, the value of one factor in the characteristic variable is changed each time, the concentration of pollutants in the water is measured, and the pollutant concentration value is obtained; Methods for constructing a predictive model for effluent water quality index (WQI) based on pollutant concentrations include: The support vector regression (SVR) model is used to predict the effluent water quality indicators, which are pollutant concentrations. The particle swarm optimization algorithm (PSO) is used to optimize the hyperparameters of the vector regression machine (SVR) model, including the penalty factor C and the kernel function parameter gamma, to construct a PSO-SVR effluent water quality prediction model.

[0016] As a further solution of the present invention: the method of optimizing the hyperparameters of the vector regression machine (SVR) model using the particle swarm optimization algorithm (PSO) includes: Setting the target parameter range, which includes the number of particles, the number of iterations and the learning factor, can avoid falling into the dilemma of local optimal solution by setting the target parameter range, which is conducive to improving the accuracy and comprehensiveness of the prediction of the PSO-SVR effluent water quality prediction model; The K-fold cross-validation method was used to validate the model, and indicators such as the coefficient of determination (R²), Nash-Shapley efficiency (NSE), root mean square error (RMSE), and mean absolute percentage error (MAPE) were used to comprehensively evaluate the model performance.

[0017] In the second aspect, the present invention also provides a treatment device, which adopts the overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm as described in the above scheme, and the treatment device includes: a reaction tank, a sedimentation tank and a water quality analyzer. One side of the reaction tank is connected to the sedimentation tank through a pipeline, and the sedimentation tank is connected to the water quality analyzer. The water quality analyzer is used to analyze the concentrations of SS, COD, TN, NH3-N and TP in the clear liquid from the sedimentation tank.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention comprehensively considers the synergistic removal of multiple pollutants and uses support vector regression (SVR) and particle swarm optimization algorithm (PSO) to optimize the coupling process parameters of sodium hypochlorite (NaClO) oxidation and polyaluminium chloride (PACl) coagulation, which can effectively improve the treatment effect of urban overflow sewage and ensure the safety and sustainable development of the water environment.

[0019] 2. The present invention can effectively and synergistically remove various pollutants in overflow sewage, including SS, COD, TOC, TN, NH3-N and TP, by optimizing the coagulation and oxidation processes, thereby significantly improving water quality. Currently, there is little research on the control process for the simultaneous analysis and synergistic removal of pollutants such as carbon, nitrogen and phosphorus in overflow sewage. The present invention fills this gap and improves the water environment quality.

[0020] 3. The present invention can save sewage treatment costs by accurately controlling the coagulation and oxidation sequence, and the dosage of coagulants and oxidants, thereby improving the overall capacity of urban sewage treatment. It can treat overflow sewage with complex pollution of different loads, flexibly adapt to changes in different pollutant concentrations and water quality characteristics, has excellent adaptability and practicality, and can effectively cope with various complex water quality challenges in practical applications.

[0021] 4. The present invention uses the prediction model established by SVR and PSO to accurately predict the effluent water quality after overflow sewage treatment, providing a scientific basis for subsequent process adjustments; it can provide new ideas and methods for future water treatment technology and promote technological progress in the field of sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a pollutant removal rate diagram of various sewage treatment agent addition methods of the present invention; Figure 2 The figure is a flow chart of the method framework of the present invention. DETAILED DESCRIPTION

[0023] 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.

[0024] See also Figure 1-2 In an embodiment of the present invention, a method for coagulation-oxidation treatment of overflow sewage based on support vector regression and particle swarm optimization algorithm is provided, and the method is used to control the concentration of pollutants in overflow sewage, and the method comprises: S1: Select the optimal treatment method for overflow sewage from a variety of sewage treatment agent addition methods, which can realize the pretreatment of overflow sewage, and improve the convergence speed of the model by performing correlation analysis on various characteristic variables affecting the effluent water quality and using standardization methods to eliminate dimensional differences; S2: Under the conditions of the optimal treatment method, measure the effluent pollutant concentration under the influence of a single characteristic variable, and judge the treatment effect based on the correlation between the pollutant concentration and the degree of water cleanliness; S3: Construct a prediction model for effluent water quality index (WQI) based on pollutant concentrations.

[0025] Preferably, the pollutants are SS, COD, TN, NH3-N and TP, and the overflow sewage from the sewage pipe is taken, and its water quality characteristics are: SS = 396 mg / L, NH3-N = 21.14 mg / L, TN = 22.52 mg / L, COD = 302.5 mg / L, TP = 1.32mg / L, pH = 8.1 and water temperature = 25 °C.

[0026] Preferably, the method of selecting the optimal treatment method for overflow sewage from a variety of sewage treatment agent addition methods includes: The overflow sewage to be treated is placed in a reaction container, and sewage treatment agents are added to the reaction container in a certain order to separate the overflow sewage into layers; Calculate the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage; All result data are compared pairwise, and the result data corresponding to the smallest water quality index (WQI) is selected as the optimal result data. The processing method that obtains the optimal result data is used as the optimal treatment method. By comparing and analyzing the effects of different reagent addition sequences on the overflow sewage treatment results, the optimal reagent addition sequence and reagent treatment method can be quickly determined, which is beneficial to improving the water treatment effect and efficiency of overflow sewage.

[0027] Preferably, the first water treatment agent is a coagulant. By using a coagulant as the first water treatment agent, the tiny particles in the sewage can be aggregated into flocs through chemical or physical effects, which is convenient for subsequent precipitation and filtration treatment. The second water treatment agent is an oxidant. The oxidant can oxidize the COD in the sewage, which is beneficial to remove organic matter in the sewage through oxidation, improve the odor of the sewage, and reduce the color of the sewage by oxidizing the organic pigments in the sewage.

[0028] Preferably, the coagulant is a polyaluminium chloride (PACl) solution, the concentration of the polyaluminium chloride (PACl) solution is 250 mg / L, and the oxidant is a sodium hypochlorite (NaClO) solution, the concentration of the sodium hypochlorite (NaClO) solution is 200 mg / L.

[0029] Preferably, the method of calculating the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage comprises: The pollution index calculation formula is used Calculate the water pollution index, where i is the type of pollutant; I i is the water pollution index of pollutant i; C i is the concentration of pollutant i; S i It is the evaluation standard of pollutant i. The evaluation standard of single indicator refers to the three-level standard in the national standard "Pollutant Discharge Standard for Urban Wastewater Treatment Plants" (GB 18918-2002) in water. The smaller the WQI value, the higher the degree of water cleanliness.

[0030] Preferably, the method of adding sewage treatment agents to the reaction vessel in a certain order comprises: Conducting a simultaneous coagulation-oxidation treatment experiment for overflow sewage: adding a first water treatment agent and a second water treatment agent to a first reaction container simultaneously to obtain a first solution; forming a simultaneous coagulation-oxidation treatment method; Methods for stratifying overflow sewage include: After stirring the first solution at a speed of 250 r / min for 30 seconds, the first solution was stirred at a speed of 50 r / min for 4.5 minutes; The stirred first solution was allowed to settle for 5 minutes to obtain a first layered solution; The method for calculating the water quality index (WQI) of overflow sewage to obtain the result data of overflow sewage includes: Measure the pollutant concentration in the first layer solution, such as Figure 1 As shown, the SS removal efficiency is 82.33%, the COD removal efficiency is 0%, the TN removal efficiency is 79.77%, the NH3-N removal efficiency is 77.53%, and the TP removal efficiency is 85%; Based on the pollutant concentration, the water quality index (WQI) of the first layered solution is calculated using a pollution index calculation formula, and a first pollution index is obtained according to the calculation result.

[0031] Preferably, the method of adding sewage treatment agents to the reaction container in a certain order to stratify the overflow sewage also includes: Conduct a pre-coagulation-oxidation treatment experiment on overflow sewage: add the first water treatment agent into the second reaction container to obtain a second solution, stir the second solution at a speed of 250 r / min for 1 minute, and let the second solution stand for 5 minutes after the stirring is completed; Adding a second water treatment agent to the second solution after standing, stirring the second solution with the second water treatment agent added at a speed of 100 r / min for 5 minutes, and after the stirring is completed, standing the second solution for 5 minutes to obtain a second layered solution; The method for calculating the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage also includes: The pollutant concentration in the second layer solution is measured, such as Figure 1 As shown, the SS removal efficiency is 37.90%, the TN removal efficiency is 11.05%, the NH3-N removal efficiency is 20.70%, the COD removal efficiency is 21.2%, and the TP removal efficiency is 86%; Based on the pollutant concentration, the water quality index (WQI) of the second layered solution is calculated using a pollution index calculation formula, and the second pollution index is obtained according to the calculation result.

[0032] Preferably, the method of adding sewage treatment agents to the reaction container in a certain order to stratify the overflow sewage also includes: Conducting a pre-oxidation-coagulation treatment experiment on overflow sewage, adding the second water treatment agent into the third reaction container to obtain a third solution, stirring the third solution at a speed of 50 r / min for 5 minutes, and adding the first water treatment agent to the stirred third solution; forming a pre-oxidation-coagulation treatment method; After stirring at 250 r / min for 1 min, the mixture was allowed to settle for 5 min to obtain the third layer solution; The method for calculating the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage also includes: The pollutant concentration in the third layer solution is measured, such as Figure 1 As shown, the SS removal rate is 99.37%, the TN removal rate is 85.74%, the NH3-N removal rate is 88.28%, the COD removal rate is 0%, and the TP removal rate is 84%; based on the pollutant concentration, the pollution index calculation formula is used to calculate the water quality pollution index (WQI) of the third layered solution, and the third pollution index is obtained according to the calculation results.

[0033] Calculate the WQI of the effluent after treating the overflow sewage with different coagulation and oxidation sequences, and compare the WQI values ​​after treatment with different processes, as shown in Table 1:

[0034] Table 1 WQI values ​​of effluent after treating overflow sewage with different coagulation and oxidation sequences.

[0035]

[0036] The WQI value was the lowest when the overflow sewage was treated by pre-oxidation-coagulation. Therefore, pre-oxidation-coagulation was the optimal process for overflow sewage treatment.

[0037] Preferably, the single characteristic variable includes: any one of the factors of coagulant concentration value, oxidant concentration value, coagulation time, oxidation time, pH value, water temperature value and influent water quality data value. By introducing characteristic variables including pH value, water temperature value and influent water quality, it is beneficial to increase the breadth of characteristic variables to improve the prediction accuracy of the model; Under the conditions of the optimal treatment method, the methods for measuring the concentration of effluent pollutants under the influence of individual characteristic variables include: According to the optimal treatment method, the value of one factor in the characteristic variable is changed each time, the concentration of pollutants in the water is measured, and the pollutant concentration value is obtained; The treatment effects of overflow sewage under different coagulant concentrations, oxidant concentrations, coagulation time, oxidation time, pH value, water temperature, and influent water quality conditions were investigated respectively; Under the conditions of the optimal treatment method, the concentration of coagulant was controlled at 50 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L, 350 mg / L and 400 mg / L; The concentration of oxidant was controlled at 50 mg / L, 100 mg / L, 150 mg / L, 200 mg / L, 250 mg / L, 300 mg / L, 350 mg / L, and 400 mg / L; The coagulation time was controlled to be 30 s, 1 min, 2 min, 3 min, 4 min, and 5 min; The oxidation time was controlled to be 30 s, 1 min, 3 min, 5 min, 10 min, and 15 min; The pH value was controlled at 5, 6, 7, 8, and 9; Water temperature was controlled at 10, 15, 20, 25, and 30 °C; SS is controlled at 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, 500 mg / L, and 600 mg / L; The concentration of NH3-N was controlled at 10 mg / L, 15 mg / L, 20 mg / L, 25 mg / L and 30 mg / L; The concentration of COD was controlled at 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, and 500 mg / L; The concentration of TP was controlled at 0.5 mg / L, 1 mg / L, 1.5 mg / L, 2 mg / L and 2.5 mg / L. Experiments were carried out to analyze the removal effect of conventional pollutants in overflow sewage, and the effluent WQI index was calculated.

[0038] Methods for constructing a predictive model for effluent water quality index (WQI) based on pollutant concentrations include: The support vector regression (SVR) model is used to predict the effluent water quality indicators, which are pollutant concentrations. The particle swarm optimization algorithm (PSO) is used to optimize the hyperparameters of the vector regression machine (SVR) model, including the penalty factor C and the kernel function parameter gamma, to construct a PSO-SVR effluent water quality prediction model.

[0039] Specifically, a prediction model for effluent WQI was established, and the R², NSE, RMSE, and MAPE indicators were used to comprehensively evaluate the model performance. The results are shown in Table 2 below:

[0040] Table 2 Performance evaluation results of the support vector regression machine (SVR) model under particle swarm optimization algorithm (PSO) optimization.

[0041]

[0042] R² = 0.881~0.938, NSE = 0.879 ~0.937, RMSE = 2.713~3.752 ng / L, MAPE =32.85%~36.59%, indicating that the evaluation model has high predictive performance.

[0043] The results show that under the water quality conditions in step (1), when WQI is controlled to 1, the optimal dosage concentrations of coagulant and oxidant in the pre-oxidation-coagulation process are 250 mg / L and 232 mg / L, respectively, and the optimal coagulation and oxidation times are 1 min and 5 min, respectively.

[0044] Preferably, the method of optimizing the hyperparameters of the vector regression machine (SVR) model using the particle swarm optimization algorithm (PSO) includes: Setting the target parameter range, including the number of particles, number of iterations and learning factor, can avoid falling into the dilemma of local optimal solution by setting the target parameter range, which is conducive to improving the accuracy and comprehensiveness of the PSO-SVR effluent water quality prediction model; The K-fold cross-validation method was used to verify the model, and indicators such as the coefficient of determination (R²), Nash-Shapley efficiency coefficient (NSE), root mean square error (RMSE), and mean absolute percentage error (MAPE) were used to comprehensively evaluate the model performance. The present invention can provide an efficient coagulation-oxidation treatment solution for overflow sewage with different water quality characteristics, providing new technical support for the field of sewage treatment.

[0045] In the second aspect, the present invention also provides a treatment device, which adopts the overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm as the above-mentioned scheme, and the treatment device includes: a reaction tank, a sedimentation tank and a water quality analyzer. One side of the reaction tank is connected to the sedimentation tank through a pipeline, and the sedimentation tank is connected to the water quality analyzer. The water quality analyzer is used to analyze the concentrations of SS, COD, TN, NH3-N and TP in the clear liquid from the sedimentation tank.

[0046] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for coagulation-oxidation treatment of overflow sewage based on support vector regression and particle swarm optimization algorithm, characterized in that: The method is used to control the concentration of pollutants in overflow sewage, and the method comprises: Select the best treatment method for overflow sewage from a variety of sewage treatment agent addition methods; Under the conditions of the optimal treatment method, the concentration of effluent pollutants under the influence of individual characteristic variables is measured respectively; A prediction model for effluent water quality index (WQI) was constructed based on pollutant concentrations.

2. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 1 is characterized in that: The pollutants are SS, COD, TN, NH3-N and TP.

3. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 2 is characterized in that: The method for selecting the optimal treatment method for overflow sewage from a plurality of sewage treatment agent addition methods includes: The overflow sewage to be treated is placed in a reaction container, and sewage treatment agents are added to the reaction container in a certain order to separate the overflow sewage into layers; Calculate the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage; All result data are compared pairwise, and the result data corresponding to the smallest water quality index (WQI) is selected as the optimal result data, and the processing method that obtains the optimal result data is taken as the optimal processing method.

4. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 3 is characterized in that: The first water treatment agent is a coagulant, and the second water treatment agent is an oxidant.

5. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 4 is characterized in that: The coagulant is a polyaluminium chloride (PACl) solution, the concentration of which is 250 mg / L, and the oxidant is a sodium hypochlorite (NaClO) solution, the concentration of which is 200 mg / L.

6. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 5 is characterized in that: The method for calculating the water quality index (WQI) of overflow sewage to obtain result data of overflow sewage includes: The pollution index calculation formula is used Calculate the water pollution index, where i is the type of pollutant; I i is the water pollution index of pollutant i; C i is the concentration of pollutant i; S i is the evaluation standard for pollutant i.

7. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 6 is characterized in that: The method of adding sewage treatment agents to the reaction container in a certain order comprises: Adding a first water treatment agent and a second water treatment agent simultaneously into a first reaction container to obtain a first solution; forming a synchronous coagulation-oxidation treatment method; The method for stratifying overflow sewage comprises: After stirring the first solution at a speed of 250 r / min for 30 seconds, the first solution was stirred at a speed of 50 r / min for 4 to 5 minutes; The stirred first solution was allowed to settle for 5 minutes to obtain a first layered solution; The method for calculating the water quality index (WQI) of overflow sewage to obtain the result data of overflow sewage includes: Measuring the pollutant concentration value in the first layer solution; Based on the pollutant concentration, the water quality index (WQI) of the first layered solution is calculated using the pollution index calculation formula, and a first pollution index is obtained according to the calculation result.

8. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 7 is characterized in that: The method of adding sewage treatment agents to the reaction container in a certain order to stratify the overflow sewage also includes: Add the first water treatment agent into the second reaction container to obtain a second solution, stir the second solution at a speed of 250 r / min for 1 minute, and allow the second solution to stand for 5 minutes after the stirring is completed; Adding a second water treatment agent to the second solution after standing, stirring the second solution with the second water treatment agent added at a speed of 100 r / min for 5 minutes, and after the stirring is completed, standing the second solution for 5 minutes to obtain a second layered solution; The method for calculating the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage also includes: measuring the concentration of pollutants in the second layer solution; Based on the pollutant concentration, the water quality index (WQI) of the second layered solution is calculated using the pollution index calculation formula, and a second pollution index is obtained according to the calculation result.

9. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 8 is characterized in that: The method of adding sewage treatment agents to the reaction container in a certain order to stratify the overflow sewage also includes: Adding the second water treatment agent into the third reaction container to obtain a third solution, stirring the third solution at a speed of 50 r / min for 5 min, and adding the first water treatment agent to the stirred third solution; After stirring at 250 r / min for 1 min, the mixture was allowed to settle for 5 min to obtain the third layer solution; The method for calculating the water quality index (WQI) of the overflow sewage to obtain the result data of the overflow sewage also includes: measuring the concentration of pollutants in the third layer solution; Based on the pollutant concentration, the water quality index (WQI) of the third layered solution is calculated using the pollution index calculation formula, and a third pollution index is obtained according to the calculation result.

10. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 9, characterized in that: The single characteristic variable includes: any one of the factors of coagulant concentration value, oxidant concentration value, coagulation time, oxidation time, pH value, water temperature value and influent water quality data value. By introducing characteristic variables including pH value, water temperature value and influent water quality, it is beneficial to increase the breadth of characteristic variables to improve the prediction accuracy of the model; The method for measuring the concentration of effluent pollutants under the influence of a single characteristic variable under the condition of the optimal treatment method includes: According to the optimal treatment method, the value of one factor in the characteristic variable is changed each time, the concentration of pollutants in the water is measured, and the pollutant concentration value is obtained; Methods for constructing a predictive model for effluent water quality index (WQI) based on pollutant concentrations include: The support vector regression (SVR) model is used to predict the effluent water quality indicators, which are pollutant concentrations. The particle swarm optimization algorithm (PSO) is used to optimize the hyperparameters of the vector regression machine (SVR) model, including the penalty factor C and the kernel function parameter gamma, to construct a PSO-SVR effluent water quality prediction model.

11. The overflow sewage coagulation-oxidation treatment method based on support vector regression and particle swarm optimization algorithm according to claim 10, characterized in that: Methods for optimizing the hyperparameters of the vector regression machine (SVR) model using the particle swarm optimization algorithm (PSO) include: Set target parameter ranges; The K-fold cross-validation method was used to validate the model.

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