Comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection

Abstract

The present invention provides a comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection, comprising the steps of filtering secondary effluent from a sewage treatment plant using a microporous filter membrane, then adding peracetic acid to prepare a mixed solution of peracetic acid and water samples of different concentrations; subjecting the mixed solution to far-ultraviolet irradiation and sampling during the disinfection process; and performing multi-dimensional analysis on the samples. The comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection of the present invention can evaluate the degradation characteristics, molecular response characteristics and influence on the disinfection system effect of dissolved organic matter in sewage during the far-ultraviolet / peracetic acid combined disinfection process in multiple dimensions. Through machine learning modeling, a scientific basis is provided for optimizing the sewage disinfection process, thereby achieving precise control of the disinfection process.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection. Background Art

[0002] With the acceleration of urbanization, sewage discharge continues to increase, and the types of pollutants it contains are becoming increasingly complex. These pollutants include not only organic and inorganic substances, but also pathogenic microorganisms such as bacteria, viruses, and parasites. The goal of urban sewage treatment is to remove or transform these pollutants, especially pathogens. To reduce the spread of these pathogens and ensure water quality, sewage disinfection has become an indispensable final step in the sewage treatment process.

[0003] Currently, commonly used disinfection technologies include chlorine, ozone, and ultraviolet (UV) disinfection. Chlorine disinfection is economical but may produce harmful disinfection byproducts; ozone disinfection has strong bactericidal properties but is energy-intensive and requires on-site preparation; UV disinfection has gained widespread use in recent years due to its lack of byproducts and ease of operation. Far-UVC disinfection technology (Far-UVC) is an emerging UV disinfection method with a wavelength range of 200 to 230 nanometers. Compared to traditional 254-nanometer UVC, 222-nanometer far-UVC is significantly less harmful to human skin and eyes and has not been found to pose a health risk to humans at effective disinfection doses. Traditional UV-ADO technologies (such as those using UVC wavelengths of 254 nm, 265 nm, and 365 nm) are widely used in water treatment. However, compared to traditional UV-ADO technologies, Far-UVC (typically referring to UVC wavelengths of 222 nm) produces higher photon energy, effectively activating the oxidation process and producing more oxidatively active species, demonstrating superior disinfection and water treatment effectiveness. Peracetic acid, a strong oxidant, primarily disinfects pathogens by oxidizing the cellular components of pathogenic microorganisms, producing significantly fewer harmful byproducts during the disinfection process. Its application in wastewater disinfection is gaining increasing attention. As emerging pollutants enter the aquatic environment, the removal effectiveness of traditional wastewater disinfection technologies is limited. Far-UVC / peracetic acid disinfection technology, however, demonstrates greater potential for removing antibiotics and other recalcitrant substances.

[0004] Dissolved organic matter (DOM) in secondary effluent refers to solvent-based organic matter released from the secondary treatment process of a wastewater treatment plant. It primarily consists of three components: natural organic matter (NOM), such as humic acid; soluble microbial products (SMPs); and recalcitrant synthetic organic matter. The complexity of these components makes the properties and behavior of DOM crucial for disinfection. Wastewater disinfection not only alters the structural properties of DOM but also affects its photochemical activity. After disinfection, the concentrations of oxidatively active components in DOM may change, thereby affecting the disinfection mechanism and efficiency. For example, DOM treated with low-concentration chlorine disinfection may promote the photodegradation of organic pollutants in water, while high-concentration chlorine treatment may inhibit this photodegradation. Therefore, as a key component of water, DOM's transformation characteristics during disinfection and its impact on disinfection effectiveness warrant further study. However, research evaluating the stress response of DOM in wastewater to far-UV / peracetic acid disinfection is currently insufficient. Summary of the Invention

[0005] The present invention aims to provide a comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection, so as to solve the related problems existing in the prior art.

[0006] Specifically, the comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection of the present invention comprises the following steps:

[0007] Step 1: Filter secondary effluent from a sewage treatment plant using a 0.45 μm microporous filter membrane, then add peracetic acid (PAA) to prepare mixed solutions of peracetic acid and water samples at varying concentrations. The method of the present invention first filters the secondary effluent from the sewage treatment plant using a 0.45 μm microporous filter membrane to remove suspended particulate matter, while retaining dissolved organic matter in the filtered water sample.

[0008] Step 2: The mixed solution obtained in step 1 is subjected to far ultraviolet (UV 222 ) irradiation, sampling during the sterilization process;

[0009] Step 3: Perform multi-dimensional analysis on the samples taken in step 2 to evaluate the response characteristics of the components in each dimension.

[0010] Furthermore, the peracetic acid concentrations in the mixed solutions prepared in step 1 are 0 mg / L, 1 mg / L, 5 mg / L, 10 mg / L, 20 mg / L and 30 mg / L, respectively; that is, six groups of filtered water samples are prepared, and peracetic acid solutions are added to them respectively, so that the peracetic acid concentrations of the six groups of water samples + peracetic acid mixed solutions are 0 mg / L, 1 mg / L, 5 mg / L, 10 mg / L, 20 mg / L and 30 mg / L, respectively.

[0011] Furthermore, in step 2, the far-UVC irradiation lamp power is 20 W, and the irradiation time is 0-60 minutes, and far-UVC irradiation is performed to analyze the pressure response mechanism of dissolved organic matter in multiple dimensions.

[0012] Furthermore, the analysis dimensions in step 3 include: S1-UV analysis of UV 254 Parameter determination and its three-dimensional fluorescence-parallel factor analysis, S2-Fourier transform infrared spectroscopy combined with two-dimensional correlation spectroscopy analysis, S3-gel permeation chromatography analysis, Fourier transform ion cyclotron resonance mass spectrometry analysis combined with machine learning, S4-electron paramagnetic resonance analysis.

[0013] Furthermore, S1-UV analysis of UV 254 The specific steps for parameter determination and three-dimensional fluorescence-parallel factor analysis are as follows:

[0014] S11. Adjust the UV spectrophotometer to 254 nm wavelength, calibrate the instrument, place the water sample in a cuvette and measure its absorbance. For chemical oxygen demand, refer to the standard method of the Ministry of Environment "HJ / T399-2007 Water quality - Determination of chemical oxygen demand - Rapid spectrophotometric method". Take 2 mL of the sample and heat it with sulfuric acid and potassium dichromate (a strong oxidizer) at 165°C for 20 minutes. Let it stand at room temperature and place it in a water quality detector for measurement.

[0015] S12, setting the excitation wavelength and emission wavelength, and adjusting the scanning speed and wavelength interval, then calibrating the instrument using a standard solution, performing an excitation-emission scan and recording the data, and finally analyzing the data using parallel factor analysis to generate a three-dimensional fluorescence map of the three fluorescent components;

[0016] S13. Analyze and compare the changes in fluorescence intensity of the three fluorescent components in step S12 during the far-ultraviolet / peracetic acid disinfection process.

[0017] Furthermore, the excitation wavelength is 200-500 nm, and the emission wavelength is 200-600 nm.

[0018] Furthermore, in step S12, the EEMCut function was used to cut the data to remove edge effects in the parallel factor analysis, and the OutlierTest function was used to detect and remove outliers. The effectiveness of the model was evaluated by EvalModel, and the performance of different factor models was compared using CompareSpecSSE. The data were split into three components and half-split validation was passed. At the same time, ComponentEEM and ModelOut were used to analyze the three-dimensional fluorescence data and export the results.

[0019] The chemical oxygen demand (COD) and 254 nm absorbance (UV) of the six disinfection systems were compared before and after disinfection. 254 , ultraviolet absorption at 254 nm) indicators were used to preliminarily evaluate the removal effect of dissolved organic matter during the far-UVC / peracetic acid disinfection process. The group with the best removal effect, i.e., the group with a peracetic acid concentration of 30 mg / L, was selected for subsequent analysis. Next, three-dimensional fluorescence spectroscopy technology was used in combination with Matlab parallel factor analysis modeling to extract the three fluorescent components of dissolved organic matter, and the pressure response of the fluorescent components of dissolved organic matter was determined.

[0020] Three-dimensional fluorescence-parallel factor analysis is mainly based on the three-dimensional fluorescence data of the collected samples. The fluorescence data is decomposed into multiple potential factors (i.e., the fluorescence components of the sample) using a parallel factor model. The excitation spectrum, emission light spectrum and relative fluorescence intensity of each factor are extracted through an optimization algorithm. The response of dissolved organic matter to far-UV / peracetic acid disinfection is evaluated based on the changes in fluorescence intensity during the disinfection process.

[0021] Furthermore, the steps of S2-Fourier transform infrared spectroscopy combined with two-dimensional correlation spectroscopy analysis are as follows:

[0022] S21, collecting infrared spectrum data of the sample by Fourier transform infrared spectroscopy technology, and organizing the data into a three-dimensional data matrix;

[0023] S22. Perform a two-dimensional Fourier transform on the matrix data in step S21 to generate two-dimensional related synchronous and asynchronous spectra, thereby revealing the coordinated changes and temporal differences of the functional groups of the substances and evaluating the dynamic response of the substance structure during the far-UV / peracetic acid disinfection process.

[0024] The dynamic response of functional groups of soluble organic matter during disinfection was identified by Fourier transform infrared spectroscopy, and the reaction order of different functional groups was further revealed by combining two-dimensional correlation spectroscopy technology.

[0025] Furthermore, the specific steps of S3-gel permeation chromatography analysis, Fourier transform ion cyclotron resonance mass spectrometry analysis and machine learning are as follows:

[0026] S31. By passing the sample solution through a chromatographic column filled with a porous gel, the molecules of different sizes are separated according to their degree of penetration in the pores, and the relative molecular weight of the substance is calculated by measuring the time it takes for different molecules to flow out of the column;

[0027] S32. After testing samples obtained during the far-UV / peracetic acid disinfection process, use known carbon, hydrogen, and oxygen (CHO) compounds in dissolved organic matter for internal standard calibration. After calibration, perform molecular formula matching on the mass spectrometry data using the S / N ratio > 4 standard. The screening criteria include retaining hydrogen-to-carbon (H / C) and oxygen-to-carbon (O / C) ratios within a specific range, and screening for molecular formulas that meet the criteria based on the deoxygenated double bond equivalent (DBE-O) value;

[0028] S33. Analyze the detected mass spectrometry peaks (100-800 Da). The results include molecular formula and corresponding molecular composition.

[0029] S34. The Fourier transform ion cyclotron resonance mass spectrometry data were divided into training and test sets. Grid search was used to tune the hyperparameters of the XGBoost model, train the final model, and perform predictions. Feature importance analysis was performed using Shapley Additive exPlanation (SHAP), and the results were visualized using a Sankey diagram to evaluate the impact of the molecular properties of substances on the molecular reaction characteristics during the far-UVC / peracetic acid disinfection process.

[0030] Dissolved organic matter (DO) molecules in secondary effluent are primarily concentrated in the 300-500 Da range. During the far-UVC / peracetic acid disinfection process, these molecules shift toward high H / C ratios and high O / C ratios, transforming from a low saturation, high aromaticity, and low oxidation state to a high saturation, low aromaticity, and low oxidation state. Molecular weight and O / C ratio are the parameters that most significantly influence molecular reactivity.

[0031] Combining Fourier transform ion cyclotron resonance mass spectrometry and gel permeation chromatography, the molecular weight distribution characteristics of dissolved organic matter at four time points during the disinfection process were evaluated. Based on mass spectrometry data, the changes in the molecular characteristics of dissolved organic matter during the disinfection process were deeply analyzed, including carbon-hydrogen ratio, carbon-oxygen ratio, deoxygenation double bond equivalent to carbon number ratio ((DBE-O) / C, double bond equivalent minus oxygen per carbon), modified aromaticity index (AI mod, modified aromaticityindex), nominal oxidation state of carbon (NOSC), and important parameters such as the number of various atoms. The results showed that with the progress of disinfection, the H / C ratio and O / C ratio of dissolved organic matter molecules showed an increasing trend. Through these data, combined with machine learning methods, it was further determined that the oxygen-carbon ratio and molecular weight are important parameters affecting the reactivity of dissolved organic matter molecules, thereby revealing the potential influence of molecular structure on conversion characteristics and reaction behavior; in order to further evaluate the effect of dissolved organic matter on the effect of far-UV / peracetic acid disinfection.

[0032] Furthermore, the specific steps of S4-electron paramagnetic resonance analysis are as follows:

[0033] S41, selecting a suitable electron spin trapping agent and adding it to the water sample + far-UV / peracetic acid system and the deionized water + far-UV / peracetic acid system;

[0034] S42. Using electron paramagnetic resonance technology, the spectral signals of the capture agent adducts in the samples collected from the water sample + far-UV / peracetic acid system and the deionized water + far-UV / peracetic acid system are detected, and the characteristic superheterodyne signals are analyzed to determine the types and relative concentrations of the oxidatively active species.

[0035] Furthermore, the electron spin trapping agent is selected from one of 5-(diisopropoxyphosphoryl)-5-methyl-1-pyrroline N-oxide (DIPPMPO, 5-diisopropoxyphosphoryl-5-methyl-1-pyrroline-N-oxide), 5,5-dimethyl-1-pyrroline-N-oxide (DMPO, 5,5-Dimethyl-1-pyrroline-N-oxide), and 2,2,6,6-tetramethylpiperidine (TEMP, 2,2,6,6-tetramethyl-4-piperidinol).

[0036] DIPPMPO is mainly used to capture methyl radicals (·CH3), DMPO is used to identify hydroxyl radicals (·OH), and TEMP is used to capture singlet oxygen ( 1 O2).

[0037] The hydroxyl radical (·OH), methyl radical (·CH3) and singlet oxygen ( 1O2) and other oxidative active species were identified and analyzed to determine that the presence of dissolved organic matter can promote the generation of oxidative active species in the system; finally, with the help of multivariate correlation network heat map analysis, the degradation characteristics, molecular characteristics, fluorescence component responses and associated effects on the generation of oxidative active species of dissolved organic matter in sewage during the far-UV / peracetic acid disinfection process were comprehensively evaluated.

[0038] Compared with the prior art, the present invention has the following outstanding features and advantages:

[0039] 1. The comprehensive evaluation method adopted in the present invention analyzes the degradation characteristics, fluorescence characteristics, molecular property changes of dissolved organic matter and its impact on the generation of oxidatively active species in multiple dimensions, thereby providing data support and theoretical basis for optimizing the disinfection effect, which helps to improve the disinfection efficiency and safety in the sewage treatment process.

[0040] 2. The comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-UV / peracetic acid disinfection of the present invention is applicable to the multi-dimensional evaluation of the pressure response of dissolved organic matter under far-UV / peracetic acid disinfection. In addition, the combined disinfection of peracetic acid and far-UV has significant advantages in practical applications, including efficient bactericidal ability, synergistic effect, wide applicability and reduced risk of drug resistance. This combined disinfection technology is not only environmentally friendly and low-cost, but also can improve disinfection efficiency, reduce chemical dosage and ultraviolet radiation intensity, and reduce resistance problems. The combination of the two can also reduce operating and maintenance costs, providing an economical and efficient disinfection solution.

[0041] 3. The present invention's comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection uses a multi-dimensional analysis method, including ultraviolet analysis, three-dimensional fluorescence spectroscopy, Fourier transform infrared spectroscopy, mass spectrometry, etc., to comprehensively evaluate the degradation characteristics and molecular structure changes of dissolved organic matter during far-ultraviolet / peracetic acid disinfection. The results show that the dissolved organic matter in the secondary effluent shows an obvious degradation trend during the far-ultraviolet / peracetic acid disinfection process. When the peracetic acid concentration is 30 mg / L, the chemical oxygen demand removal rate is 64%, and the UV 254 The removal rate was 39.22% and the fluorescence intensity response decreased by 66.09%; during the far-UV / peracetic acid disinfection process, the molecules of dissolved organic matter transformed towards high H / C and high O / C, and from low saturation, high aromaticity and low oxidation state to high saturation, low aromaticity and high oxidation state; through in-depth analysis of the changes in the molecular characteristics of dissolved organic matter and combined with machine learning for data modeling, key molecular features that affect disinfection reactivity, such as molecular weight and O / C, can be effectively identified, providing clear parameter guidance for further optimization of sewage disinfection processes.

[0042] 4. The comprehensive evaluation method of the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection of the present invention reveals that the presence of dissolved organic matter can promote the generation of oxidative active species in the system, especially for ·OH, ·CH3 and 1 The influence of species such as O2 provides a scientific basis for further optimizing the far-UV / peracetic acid combined disinfection process, and improves the disinfection efficiency and safety in the sewage treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 (a) 254 nm absorbance (UV 254 , ultravioletabsorption at 254 nm) and (b) chemical oxygen demand (COD) concentration and its removal rate;

[0044] Figure 2 Three fluorescent components were selected by fitting the fluorescence component data of dissolved organic matter during far-UV / peracetic acid disinfection using the parallel factor method in the examples (where (a), (c), and (e) are the fluorescence responses of component one, component two, and component three, respectively (region I: aromatic protein I, region II: aromatic protein II, region III: fulvic acid-like substances, region IV: soluble microbial metabolite-like substances, region V: humic acid-like substances), (b), (d), and (f) are the fluorescence loads of component one, component two, and component three, respectively);

[0045] Figure 3 1 is a graph showing the corresponding changes in the maximum fluorescence intensity (Maximum Fluorescence Intensity) of three fluorescent components, namely component 1, component 2, and component 3, during the far-ultraviolet / peracetic acid disinfection process in the embodiment;

[0046] Figure 4 The changes in functional groups and response order of dissolved organic matter during the far-UV / peracetic acid disinfection process identified by Fourier transform infrared spectroscopy combined with two-dimensional correlation spectroscopy in the embodiments ((a) two-dimensional correlation synchronous spectrum, (b) two-dimensional correlation asynchronous spectrum);

[0047] Figure 5 The abundance curves of dissolved organic molecules at (a) 0 min, (b) 15 min, (c) 30 min, and (d) 60 min during the far-UV / peracetic acid disinfection process in the examples are shown;

[0048] Figure 6The molecular weight distribution of dissolved organic matter was analyzed by gel permeation chromatography during the far-ultraviolet / peracetic acid disinfection process in the examples;

[0049] Figure 7 : VK marginal density plot of the unique molecular formula distribution during the far-UV / peracetic acid disinfection process in the embodiment (A: aliphatic / protein, B: lipid, C: lignin / CRAM-like structure, D: unsaturated hydrocarbon, E: carbohydrate, F: aromatic structure and G: tannic acid);

[0050] Figure 8 (a) Deoxygenated double bond equivalent to carbon number ratio (DBE-O) / C, double bond equivalent minus oxygen per carbon), (b) Modified aromaticity index (AI) of dissolved organic matter in the far-UV / peracetic acid disinfection process in the embodiment mod , modified aromaticity index) and (c) changes in the nominal oxidation state of carbon (NOSC);

[0051] Figure 9 Waterfall plots of the feature importance of Shapley Additive exPlanation (SHAP) for dissolved organic matter during the far-UV / peracetic acid disinfection process for (a) 0-15 min, (b) 15-30 min, and (c) 30-60 min in the example;

[0052] Figure 10 SHapley Additive exPlanation (SHAP) feature analysis of molecular characteristics during the far-UV / peracetic acid disinfection process in the examples ((a) relationship between oxygen-carbon ratio (O:C) and molecular weight (MW), (b) relationship between molecular weight (MW) and number of nitrogen atoms (nN), (c) relationship between number of nitrogen atoms (nN) and oxygen-carbon ratio (O:C));

[0053] Figure 11 A Sankey diagram showing the contribution of the normalized molecular characteristic Shapley Additive Explanation (SHAP) characteristic value to the molecular reactivity during the far-UV / peracetic acid disinfection process in the embodiment;

[0054] Figure 12In the far-UV / peracetic acid disinfection process in the embodiment, (a) 5,5-dimethyl-1-pyrroline-N-oxide (DMPO, 5,5-Dimethyl-1-pyrroline-N-oxide) is used to treat hydroxyl radicals (·OH), (b) 5-(diisopropoxyphosphoryl)-5-methyl-1-pyrroline N-oxide (DIPPMPO, 5-diisopropoxyphosphoryl-5-methyl-1-pyrroline-N-oxide) is used to treat methyl radicals (·CH3) and (c) 2,2,6,6-tetramethyl-4-piperidinol (TEMP, 2,2,6,6-tetramethyl-4-piperidinol) is used to treat singlet oxygen ( 1 Electron paramagnetic resonance spectroscopy of O2);

[0055] Figure 13 Figure 2 is a heat map showing the correlation between the composition of dissolved organic matter analyzed by three-dimensional fluorescence-parallel factor analysis and Fourier transform ion cyclotron resonance mass spectrometry and the reactive oxidative species during far-UV / peracetic acid disinfection in the examples (*, **, and *** indicate significant correlations, i.e., P < 0.05, P < 0.01, and P < 0.001). DETAILED DESCRIPTION

[0056] The following will be combined with the accompanying drawings in 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 making creative work are within the scope of protection of the present invention. The technical solutions of the present invention are further explained below with reference to implementation cases.

[0057] Example

[0058] This embodiment provides a comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection, comprising the following steps:

[0059] Step S1. Water samples were collected from the secondary effluent of a wastewater treatment plant in Jiading District, Shanghai, which utilizes an anaerobic-anoxic-oxygen (AAO) process. The water samples were first shaken to prevent sediment accumulation at the bottom, then filtered through a 0.45 μm microporous membrane and stored at 4°C. Six 250 mL aliquots of filtered water were then prepared. Peracetic acid solution was added to each of the six filtered water samples, resulting in peracetic acid concentrations of 0 mg / L, 1 mg / L, 5 mg / L, 10 mg / L, 20 mg / L, and 30 mg / L, respectively.

[0060] Step S2. The six mixed solutions were subjected to far-UVC irradiation experiments. The far-UVC power used was 20 W, the total irradiation time was 1 hour, and the distance between the light source and the liquid surface was 10 cm. Samples were taken at 0 min, 1 min, 3 min, 5 min, 10 min, 15 min, 20 min, 30 min, 45 min, and 60 min during the irradiation process. Finally, the samples were analyzed and evaluated in multiple dimensions.

[0061] Step S3. Retrieve the chemical oxygen demand (COD) and 254 nm absorbance (UV) of the water sample taken in step S2. 254 , ultraviolet absorption at 254 nm), comparing the degradation of dissolved organic matter during the far-UV / peracetic acid disinfection process at different peracetic acid concentrations. The main steps include:

[0062] Step S31. Chemical oxygen demand (COD) refers to the Ministry of Environment standard method "HJ / T399-2007 Water Quality - Determination of Chemical Oxygen Demand - Rapid Spectrophotometric Method." 2 mL of sample is placed in a test tube containing pre-prepared reagents. The sample is heated at 165°C with sulfuric acid and a strong oxidizer, potassium dichromate, for 20 minutes. The sample is allowed to cool to room temperature. A blank sample (deionized water) is placed in the COD rapid detector and the instrument is zeroed using the zero adjustment button. The test tube containing the sample to be tested is then placed in the instrument and the COD concentration is directly read using the readout button.

[0063] Step S32. Turn on the UV spectrophotometer, select a wavelength of 254 nm, use deionized water as a blank sample, add it to the cuvette of the photometer, ensure that the light path is clear, perform zero point calibration, then add the water sample to be tested to the cuvette and place it in the sample compartment of the photometer, and read the absorbance value.

[0064] like Figure 1 As shown in the figure, in the six mixed solutions, with the increase of the concentration of peracetic acid added, the UV254 ( Figure 1 (a)) and COD ( Figure 1 (b)) The removal rate increased. When the peracetic acid concentration in the system reached 30 mg / L, the UV 254 The removal rates of COD and COD were the highest, at 39.22% and 66.09%, respectively. Therefore, in the following dimensional analysis, samples with a peracetic acid concentration of 30 mg / L were used.

[0065] Step S4. Using a Cary Eclipse fluorescence spectrometer (F7100, Shimadzu, Japan), set the scan speed to 4800 nm / min, the excitation wavelength to 200–500 nm in 10 nm intervals, and the emission wavelength to 200–600 nm in 10 nm intervals. First, zero the sample using deionized water in a cuvette. Then, place 3 mL of the sample to be tested (30 mg / L peracetic acid) in the cuvette. Wipe the cuvette surface with lens paper and place it in the sample chamber. Start data acquisition. Two sets of parallel samples, totaling 24 samples, were collected at 0 min, 1 min, 3 min, 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 40 min, 50 min, and 60 min during the far-UV / peracetic acid disinfection process. Parallel factor analysis was performed using the MATLAB toolbox (DOMFluor).

[0066] The parallel factor analysis step in step S4 includes the following steps:

[0067] Step S41. Prepare three-dimensional fluorescence data and organize it into a three-dimensional array, then create a structure to store the excitation spectrum, emission spectrum, and sample data;

[0068] Step S42. Use the EEMCut function to cut the data to remove edge effects, and use the OutlierTest function to detect and remove outliers;

[0069] Step S43. Evaluate the model validity using EvalModel and compare the performance of different factor models using CompareSpecSSE, ultimately selecting a three-component model.

[0070] Step S44. Step S44. The data is split into three components and half-split and verified. ComponentEEM and ModelOut are used to analyze the three-dimensional fluorescence data and export the results.

[0071] Step S45: Compare the results derived in step S44 to evaluate the fluorescence intensity response of the fluorescent component during the far-UV / peracetic acid disinfection process.

[0072] Step S5. The samples at 0 min, 15 min, 30 min, and 60 min in step S2 were freeze-dried to ensure that the samples were uniform and suitable for Fourier transform infrared spectroscopy analysis. A Fourier transform infrared spectrometer (Thermo Fisher Scientific Nicolet iS5, USA) was used with a scanning wavelength range of 800–4000 cm -1 , resolution 4.000, sample scan times 32, for spectrum acquisition; the collected Fourier transform infrared spectral data were used to perform two-dimensional correlation spectrum mapping using origin software, and the relative positions and intensities of the mapped synchronous and asynchronous spectrum peaks were analyzed to obtain information on intermolecular interactions and dynamic changes.

[0073] Step S6. Appropriately dilute the samples (30 mg / L peracetic acid concentration) at 0 min, 15 min, 30 min, and 60 min in step S2. Bottle the samples for ease of handling and inject the prepared samples directly into a gel permeation chromatograph (Agilent PL-GPC50, USA). Calculate the molecular weight and isotype distribution of the samples based on the retention times and calibration curves.

[0074] Step S7. Samples with a 30 mg / L peracetic acid concentration at 0, 15, 30, and 60 min from Step S2 were analyzed using a Fourier transform ion cyclotron resonance mass spectrometer (Solarix 15T, Bruker Technologies, USA). A 200 μL aliquot of the sample was directly injected for mass spectrometry analysis using an electrospray ionization (ESI) source in negative ion detection mode. The mass spectral data were calibrated using known carbon, hydrogen, and oxygen (CHO) compounds as internal standards, and molecular formula matching was performed based on the specified elemental composition (e.g., carbon, hydrogen, oxygen, nitrogen, and sulfur). The screening criteria included retaining formulas with a hydrogen-to-carbon ratio (H / C) between 0.2 and 2.3, an oxygen-to-carbon ratio (O / C) between 0 and 1.2, and a deoxy double bond equivalent (DBE-O) value between -10 and 10. If multiple formulas were associated with a single m / z value, the formula with the fewest heteroatoms was selected. If multiple choices remained, the formula with the smallest error was retained as the correct answer. Analyze mass spectrometric peaks in the m / z range of 100-800 Da to obtain accurate molecular composition and generate relevant result data.

[0075] Step S8. Divide the mass spectrometry data obtained in step S7 into training and test sets. Load the necessary R packages, import and preprocess the training and test data, perform a hyperparameter grid search to optimize the model, train the final model, and make predictions on the test set. Finally, evaluate model performance using a confusion matrix, calculate the Shapley additive explained value (SHAP) for model interpretation, and visualize feature importance using a Sankey diagram.

[0076] Step S9. Set up a deionized water + far-UV / peracetic acid disinfection system and a water sample + far-UV / peracetic acid disinfection system, and analyze the oxidative active species in the two systems respectively, as follows:

[0077] Step S91. Add an appropriate amount of peracetic acid to deionized water and the water sample, respectively, to ensure that the peracetic acid concentration in both systems is 30 mg / L. Irradiate with a far-UV lamp for 60 min, with the light source 10 cm away from the page.

[0078] Step S92: 5-(diisopropoxyphosphoryl)-5-methyl-1-pyrroline N-oxide (DIPPMPO) is used to capture methyl radicals (·CH3), 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) is used to capture hydroxyl radicals (·OH), and 2,2,6,6-tetramethylpiperidine (TEMP) is used to capture singlet oxygen ( 1 O2);

[0079] Step S93. Rapidly sample at the beginning and end of the disinfection reaction, immediately mix the sampled liquid with the selected capture agent, place the prepared sample in the sample chamber for measurement, and record the electron paramagnetic resonance magnetic field strength signal;

[0080] Step S94. Analyze the obtained EPR magnetic field and intensity data to identify hydroxyl radicals (·OH), singlet oxygen ( 1 O2) and methyl radical (·CH3).

[0081] like Figure 2 As shown in the figure, a mixed solution of 30 mg / L peracetic acid and water was subjected to far-ultraviolet irradiation and then subjected to three-dimensional fluorescence-parallel factor analysis. It was found that the dissolved organic matter was composed of three fluorescent components (region I: aromatic protein I, region II: aromatic protein II, region III: fulvic acid-like substances, region IV: soluble microbial metabolite-like substances, region V: humic acid-like substances), which were fulvic acid-like substances, aromatic proteins and humic acid-like substances, respectively.

[0082] Figure 3The results show the changes in the fluorescent components and their maximum fluorescence intensities during the far-UVC / peracetic acid disinfection process. The results show that the maximum fluorescence intensity of the three fluorescent components gradually decreased during the far-UVC / peracetic acid disinfection process. Specifically, the maximum fluorescence intensities of fulvic acid-like substances (component 1), aromatic proteins (component 2), and humic acid-like substances (component 3) decreased by 64.49%, 74.74%, and 56.19%, respectively, after disinfection.

[0083] like Figure 4 As shown in the figure, a mixture of 30 mg / L peracetic acid and water was subjected to far ultraviolet irradiation and then analyzed by Fourier transform infrared two-dimensional correlation spectroscopy. Figure 4 (a) It can be seen that 1056 cm - ¹、1231 cm - ¹Related to CO stretching vibration, 1335 cm - ¹Related to CN stretching vibration, 1384 cm - ¹Related to CH stretching vibration, 1497 cm - ¹Related to the C-C stretching vibration of the aromatic ring, 1547 cm - ¹Related to the C=C stretching vibration of the aromatic ring, 1635 cm - ¹Related to C=C double bond stretching vibration, 3436 cm - ¹ is related to OH stretching vibration. From the two-dimensional correlation asynchronous spectrum ( Figure 4 (b) The reaction order was determined to be: CO stretching vibration, CN stretching vibration, aromatic ring C–H stretching vibration, C=C double bond stretching vibration, aromatic ring C=C stretching vibration, and OH stretching vibration. Fourier transform infrared two-dimensional correlation spectroscopy analysis clarified the response characteristics of different functional groups during the reaction, revealing the order and mechanism of the reaction between peracetic acid and organic matter in the water sample. CO and CN stretching vibrations appeared first, indicating that peracetic acid had a strong effect on the functional groups in the water sample. Changes in the aromatic ring and C–H and C=C double bonds reflected the gradual modification and degradation of the organic matter structure during the reaction. Finally, changes in the OH stretching vibration indicated the completion of the oxidation process or hydration.

[0084] like Figure 5As shown in the figure, the total relative intensity of each molecular weight molecule in the mixed solution of 30 mg / L peracetic acid + water sample during far-UV disinfection at (a) 0 min, (b) 15 min, (c) 30 min and (d) 60 min was analyzed. The molecular abundance at different time points is marked with different colors, highlighting the change of molecular weight during the disinfection process. The color of the scattered points is related to its proportion in the sample. As shown in the color scale, it can be seen that the molecular weight distribution in the sample is relatively concentrated, mainly distributed in 300-500 Da, and the overall change trend is not obvious.

[0085] Figure 6 The results of gel permeation chromatography analysis further confirm that the molecular weight distribution of dissolved organic matter in the far-UVC / peracetic acid disinfection system is concentrated, mainly distributed in the 300-500 Da range, and the overall change trend is not obvious.

[0086] Figure 7 、 Figure 8 is the result of Fourier transform ion cyclotron resonance mass spectrometry data analysis. Figure 7 As shown, dissolved organic matter molecules tend to transform into high oxygen-carbon ratio and high hydrogen-carbon ratio during the far-UV / peracetic acid disinfection process; Figure 8 The ratio of deoxy double bond equivalent to carbon number ((DBE-O) / C) shown in (a) can characterize the relationship between the unsaturation of a molecule and its oxygen content. A higher (DBE-O) / C value generally indicates that the molecule has more double bonds, aromatic rings, or unsaturated structures, and may contain fewer oxygen atoms. It can be seen that the (DBE-O) / C value of dissolved organic matter molecules becomes smaller and smaller during the far-UV / peracetic acid disinfection process, which means that the molecule is more saturated and may contain more oxygen atoms. Figure 8 (b) The modified aromaticity index (AI mod ) is an indicator used to characterize the aromaticity of a molecule. A higher AI mod The value indicates that the molecule has strong aromaticity. Here we can see that the dissolved organic matter molecules have strong aromaticity during the disinfection process. mod The value decreases, which means that the aromatic substances are gradually being removed; Figure 8The nominal oxidation state of carbon (NOSC), shown in (c), is a quantitative indicator used to characterize the oxidation state of carbon in a molecule. It is calculated as follows: NOSC=4−(H / C+2O / C+N / C+P / C+S / C)NOSC = 4 - (H / C + 2O / C+ N / C + P / C + S / C). Higher NOSC values ​​indicate that the carbon atoms in the molecule tend to be in higher oxidation states. These results indicate that the NOSC values ​​of the dissolved organic matter molecules increased during the disinfection process, indicating that oxidation reactions occurred in the system. Fourier transform ion cyclotron resonance mass spectrometry data analysis generally indicates that the dissolved organic matter underwent oxidation reactions during the far-UV / peracetic acid disinfection process, with the molecules tending towards saturation and oxidation. Overall, the dissolved organic matter underwent oxidative degradation, dearomatization, and saturation during the far-UV / peracetic acid disinfection process, with the oxygen content of the molecules increasing and the unsaturated structure decreasing, exhibiting distinct oxidation characteristics. These changes are a direct result of the treatment of the dissolved organic matter during the disinfection process, indicating that its molecular structure becomes simpler and richer in oxygen.

[0087] Figure 9 、 Figure 10 and Figure 11 A machine learning model based on Fourier transform ion cyclotron resonance mass spectrometry data predicts the contribution of molecular property SHAP eigenvalues ​​to molecular reactivity. Figure 9 (a), (b) and (c) show the effects of various molecular characteristics on the reaction characteristics in the 0-15min, 15-30min and 30-60min stages of disinfection, respectively. It can be seen that molecules with lower oxygen-carbon ratios are easily removed to generate molecules with higher oxygen-carbon ratios. This may be because the far-UV / peracetic acid disinfection process will produce a large number of oxidizing active species, causing the dissolved organic matter to undergo oxidation reactions and be removed and converted; the molecular weight appears in multiple sub-graphs. Although its SHAP value fluctuates slightly, its overall impact on molecular reactivity is relatively stable. Figure 10 (a), (b), and (c) show the joint effects of molecular weight, oxygen-carbon ratio, and nitrogen atom number on molecular reactivity during the 0-15 min, 15-30 min, and 30-60 min disinfection stages, respectively. It can be seen that across all categories (removal, unchanged, and production), there is a strong relationship between molecular weight and oxygen-carbon ratio, especially when the SHAP value is high. This indicates that the oxygen-carbon ratio has a greater impact on molecular reactivity. The SHAP values ​​of nitrogen atom number are more evenly distributed across all categories and have a smaller impact, especially in the removal and unchanged categories, where the nitrogen atom number has a smaller impact on molecular reactivity. Figure 11The Sankey diagram further demonstrates that the oxygen-to-carbon ratio is the most important characteristic parameter affecting molecular reactivity. This is the most important reactivity characteristic during the disinfection process. Molecules with low oxygen-to-carbon ratios tend to be removed, while molecules with high oxygen-to-carbon ratios are generated during the reaction, indicating that oxidation is the primary reaction mechanism during disinfection.

[0088] Figure 12 The effects of (a) 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) on hydroxyl radicals (·OH), (b) 5-(diisopropoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DIPPMPO) on methyl radicals (·CH3) and (c) 2,2,6,6-tetramethylpiperidine (TEMP) on singlet oxygen ( 1 O2). Deionized water is blue and secondary effluent is red. It can be seen that in the presence of dissolved organic matter, the hydroxyl radical (·OH), methyl radical (·CH3) and singlet oxygen ( 1 O2) signal is stronger, which indicates that the presence of dissolved organic matter can promote the generation of oxidative active species during the far-UV / peracetic acid disinfection process.

[0089] Figure 13 The figure shows the correlation heat map between the composition of solvent organic matter and the active oxidative species in the far-UV / peracetic acid disinfection process analyzed by three-dimensional fluorescence-parallel factor analysis and Fourier transform ion cyclotron resonance mass spectrometry (*, ** and *** indicate significant correlation, P < 0.05, P < 0.01 and P < 0.001). 254 There is a significant positive correlation between the three fluorescent components. These three indicators all characterize the high degradability of dissolved organic matter during the far-UV / peracetic acid disinfection process; the number of oxygen atoms and the oxygen-carbon ratio are significantly negatively correlated with the fluorescent components, indicating that the dissolved organic matter tends to be degraded and converted into a highly oxidized state during the far-UV / peracetic acid disinfection process.

[0090] Compared with the prior art, the above embodiment mainly achieves the following beneficial effects:

[0091] The method of the present invention for evaluating the pressure response of dissolved organic matter in sewage to far-UV / peracetic acid combined disinfection is intended to analyze and evaluate the degradation characteristics, molecular structure changes and the impact of dissolved organic matter on the generation of oxidative active species in the far-UV / peracetic acid disinfection process in multiple dimensions. This method combines ultraviolet analysis, three-dimensional fluorescence spectroscopy, Fourier transform infrared spectroscopy, mass spectrometry and other technologies to comprehensively evaluate the chemical changes in the disinfection process. The experimental results show that dissolved organic matter shows a significant degradation trend in the far-UV / peracetic acid combined disinfection process. When the peracetic acid concentration is 30 mg / L, the COD removal rate reaches 64%, UV 254 The removal rate was 39.22%, and the fluorescence intensity response decreased by 66.09%. Furthermore, molecular structural changes revealed a shift in the dissolved organic matter from a low saturation, high aromaticity, and low oxidation state to a high saturation, low aromaticity, and low oxidation state. Furthermore, data modeling combined with machine learning identified key molecular features influencing disinfection reactivity, such as molecular weight, oxygen-to-carbon ratio, and number of nitrogen atoms, providing effective parameter guidance for further optimizing wastewater disinfection processes. This invention's combined disinfection technology (far-UVC + peracetic acid) offers significant advantages: high bactericidal activity, synergistic effects, wide applicability, and reduced risk of drug resistance. This method is not only environmentally friendly and cost-effective, but also improves disinfection efficiency, reduces chemical dosage and UV irradiation intensity, and reduces operating and maintenance costs. By thoroughly analyzing the molecular changes of dissolved organic matter during the disinfection process, this invention provides a scientific basis for optimizing the far-UVC / peracetic acid combined disinfection process, enhancing disinfection efficiency and safety during wastewater treatment.

[0092] The above-described embodiments merely illustrate several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, and all such variations and improvements fall within the scope of protection of the present invention.

Claims

1. A comprehensive evaluation method for the pressure response of dissolved organic matter in sewage to far-ultraviolet / peracetic acid disinfection, characterized in that: The following steps are involved: Step 1: Filter the secondary effluent from the sewage treatment plant using a microporous filter membrane, then add peracetic acid to prepare mixed solutions of peracetic acid + water samples with different concentrations; Step 2: subjecting the mixed solution obtained in step 1 to far-ultraviolet irradiation and taking samples during the disinfection process; Step 3: Perform multi-dimensional analysis on the samples taken in step 2 to evaluate the response characteristics of the components in each dimension; Analysis dimensions include: S1-UV analysis of UV 254 Parameter determination and its three-dimensional fluorescence-parallel factor analysis, S2-Fourier transform infrared spectroscopy combined with two-dimensional correlation spectroscopy analysis, S3-gel permeation chromatography analysis, Fourier transform ion cyclotron resonance mass spectrometry analysis combined with machine learning, S4-electron paramagnetic resonance analysis; The steps of S2-Fourier transform infrared spectroscopy combined with two-dimensional correlation spectroscopy analysis are as follows: S21, collecting infrared spectrum data of the sample by Fourier transform infrared spectroscopy technology, and organizing the data into a three-dimensional data matrix; S22, performing a two-dimensional Fourier transform on the matrix data in step S21 to generate a two-dimensional related synchronous spectrum and asynchronous spectrum; The specific steps of S3-gel permeation chromatography analysis, Fourier transform ion cyclotron resonance mass spectrometry analysis and machine learning are as follows: S31. By passing the sample solution through a chromatographic column filled with a porous gel, the molecules of different sizes are separated according to their degree of penetration in the pores, and the relative molecular weight of the substance is calculated by measuring the time it takes for different molecules to flow out of the column; S32. After testing samples obtained during the far-UV / peracetic acid disinfection process, use known CHO compounds in dissolved organic matter for internal standard calibration. After calibration, perform molecular formula matching on the mass spectrometry data using a S / N ratio > 4. The screening criteria include retaining H / C and O / C values ​​within a specific range and screening for molecular formulas that meet the criteria based on the DBE-O value. S33, analyzing the detected mass spectrum peaks, the results including molecular formula and corresponding molecular composition; S34. The data from Fourier transform ion cyclotron resonance mass spectrometry analysis were divided into training and test sets. Grid search was used to tune the hyperparameters of the XGBoost model, train the final model, and perform predictions. SHAP values ​​were used for feature importance analysis, and the results were visualized using a Sankey diagram to evaluate the impact of the molecular properties of substances on the molecular reaction characteristics during the far-UVC / peracetic acid disinfection process.

2. The method according to claim 1, characterized in that The concentrations of peracetic acid in the mixed solutions prepared in step 1 were 0 mg / L, 1 mg / L, 5 mg / L, 10 mg / L, 20 mg / L and 30 mg / L, respectively.

3. The method according to claim 1, characterized in that In step 2, the far-ultraviolet irradiation lamp power is 20 W, and the irradiation time is 0-60 minutes.

4. The method according to claim 1, wherein S1-UV analysis of UV 254 The specific steps for parameter determination and three-dimensional fluorescence-parallel factor analysis are as follows: S11. Adjust the UV spectrophotometer to 254 nm wavelength, calibrate the instrument, place the sample in a cuvette, and measure its absorbance; S12, setting the excitation wavelength and emission wavelength, and adjusting the scanning speed and wavelength interval, then calibrating the instrument using a standard solution, performing an excitation-emission scan and recording the data, and finally analyzing the data using parallel factor analysis to generate a three-dimensional fluorescence map of the three fluorescent components; S13. Analyze and compare the changes in fluorescence intensity of the three fluorescent components in step S12 during the far-ultraviolet / peracetic acid disinfection process.

5. The method according to claim 4, characterized in that The excitation wavelength is 200-500 nm, and the emission wavelength is 200-600 nm.

6. The method according to claim 4, characterized in that In step S12, the EEMCut function is used to cut the data to remove edge effects in the parallel factor analysis, and the OutlierTest function is used to detect and remove outliers. The validity of the model is evaluated through EvalModel, and the performance of different factor models is compared using CompareSpecSSE. The data is split into three components and half-split verification is passed. At the same time, ComponentEEM and ModelOut are used to analyze the EEM data and export the results.

7. The method according to claim 1, characterized in that The specific steps of S4-EPR analysis are as follows: S41, selecting a suitable electron spin trapping agent and adding it to the water sample + far-UV / peracetic acid system and the deionized water + far-UV / peracetic acid system; S42. Detecting spectral signals of the capture agent adducts in the samples collected from the water sample + far-UV / peracetic acid system and the deionized water + far-UV / peracetic acid system by electron paramagnetic resonance technology, and analyzing the characteristic superheterodyne signals to determine the types and relative concentrations of the oxidatively active species; The electron spin trapping agent is selected from one of 5-(diisopropoxyphosphoryl)-5-methyl-1-pyrroline N-oxide, 5,5-dimethyl-1-pyrroline-N-oxide, and 2,2,6,6-tetramethylpiperidine.

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