Organic matter analysis system and water treatment system

Abstract

Provided are: an organic matter analysis system capable of determining the organic matter concentration in water to be treated and analyzing the characteristics of the organic matter; and a water treatment system for controlling a water treatment facility on the basis of the analysis result. The organic matter analysis system comprises: a measurement device that adds an oxidizing agent to a sample, decomposes the organic matter through chemical oxidation to generate carbon dioxide, and detects the carbon dioxide; and an analysis device 1 that acquires the detection result from the measurement device and uses the detection result to calculate the total organic carbon concentration of the sample. The analysis device 1 acquires information on the characteristics of the organic matter on the basis of the difference in total organic carbon concentration calculated according to whether an oxidizing agent is added, or when different types of oxidizing agents are added.

Description

Organic matter analysis system and water treatment system

[0001] The present invention relates to an organic matter analysis system that measures the concentration of organic matter in water to be treated and analyzes the characteristics of the organic matter, and a water treatment system that controls water treatment equipment based on the analysis results.

[0002] Total organic carbon (TOC) is a basic indicator of water quality analysis that expresses the total amount of organic matter present in water as the amount of carbon contained in the organic matter, and is widely used as an indicator for managing organic matter in water treatment.

[0003] Carbon dioxide is generated when organic matter contained in a sample for which TOC is to be measured is oxidatively decomposed. The amount of carbon dioxide generated is proportional to the amount of carbon contained in the organic matter in the oxidatively decomposed sample, so the organic carbon concentration of the sample can be calculated by measuring the amount of carbon dioxide generated and comparing it with the results obtained when a solution of known concentration (standard substance) is measured.

[0004] There are two known methods for oxidizing organic matter: combustion oxidation and wet oxidation. In the combustion oxidation method, a sample is injected into a high-temperature combustion furnace and the organic matter in the sample is burned to produce carbon dioxide. In the wet oxidation method, an oxidizing agent is added to the sample, and the organic matter in the sample is chemically oxidized and decomposed to produce carbon dioxide. Conventional TOC (total organic carbon) analyzers, regardless of their method, only measure the organic carbon concentration corresponding to the amount of organic matter in the sample, and are unable to obtain information on the characteristics of the organic matter (molecular weight, structure, solubility, etc.).

[0005] Patent Document 1 describes an ultrapure water production system in which two TOC meters with different oxidative decomposition capabilities are installed, the concentration of persistent TOC is calculated from the difference between the measured values, and when the concentration of persistent TOC exceeds a predetermined value, the amount of ultraviolet light irradiation is reduced or the water being treated is subjected to a process of decomposing / removing the persistent TOC components.

[0006] The device described in Patent Document 1 is designed for ultrapure water with a low concentration of organic matter, and so depending on the organic matter concentration, it may not be able to fully decompose the organic matter, resulting in inaccurate measurement results.In addition, it is difficult to use this device for water with a large number of organic components, such as wastewater or environmental water.

[0007] Japanese Patent Application Laid-Open No. 2016-5829

[0008] The present invention has been made in consideration of the above-mentioned conventional situation, and aims to provide an organic matter analysis system that can determine the organic matter concentration in the water to be treated and analyze the characteristics of the organic matter, and a water treatment system that controls the water treatment equipment based on the analysis results.

[0009] [1] An organic matter analysis system comprising: a measuring device that adds an oxidizing agent to a sample, decomposes organic matter by chemical oxidation to generate carbon dioxide, and detects the carbon dioxide; and an analyzing device that acquires the detection results of the measuring device and calculates the total organic carbon concentration of the sample using the detection results, wherein the analyzing device acquires information about the characteristics of the organic matter based on the difference in the calculated total organic carbon concentration when an oxidizing agent is added or when different types of oxidizing agent are added.

[0010] [2] The organic matter analysis system according to [1], wherein the characteristics of the organic matter include at least one of molecular weight, structure, functional group, constituent elements, solubility, and particle size.

[0011] [3] A water treatment system comprising: a water treatment facility; and the analysis system according to [1], wherein the sample is water to be treated that is supplied to the water treatment facility; and the analysis device controls the operating conditions of the water treatment facility based on the acquired information on the characteristics of the organic matter.

[0012] [4] An organic matter analysis system comprising: a first measurement device that adds an oxidizing agent to a sample, decomposes organic matter in the sample by chemical oxidation to generate carbon dioxide, and detects the generated carbon dioxide; a second measurement device that injects the sample into a combustion tube, combusts the organic matter in the sample to generate carbon dioxide, and detects the generated carbon dioxide; and an analysis device that calculates a first total organic carbon concentration of the sample using the detection result of the first measurement device, calculates a second total organic carbon concentration of the sample using the detection result of the second measurement device, and acquires information about the characteristics of the organic matter based on the difference between the first total organic carbon concentration and the second total organic carbon concentration.

[0013] According to the present invention, the organic matter concentration in the water to be treated can be determined and the characteristics of the organic matter can be analyzed.

[0014] It is a schematic configuration diagram of an organic substance analysis system according to an embodiment of the present invention.It is a schematic configuration diagram of an organic substance analysis system according to another embodiment.It is a schematic configuration diagram of an organic substance analysis system according to another embodiment.It is a schematic configuration diagram of an organic substance analysis system according to another embodiment.

[0015] An organic matter analyzing system according to an embodiment of the present invention uses a wet oxidation TOC measuring device that adds an oxidizing agent to a sample (sample water, water to be treated), decomposes organic matter by chemical oxidation to generate carbon dioxide, measures the amount of carbon dioxide generated, and determines the total organic carbon concentration. Different types of oxidizing agents are added to the sample, the total organic carbon concentration is calculated for each type of oxidizing agent added, and information about the characteristics of the organic matter contained in the sample is obtained from the difference between the calculated total organic carbon concentrations. Hereinafter, an embodiment will be described with reference to the drawings.

[0016] For example, as shown in FIG. 1, oxidizing agent A is added to a sample, and organic matter in the sample is chemically oxidized and decomposed to generate carbon dioxide. The oxidation reaction may be reinforced by heating (100°C or less) or ultraviolet irradiation. The generated carbon dioxide is dehumidified and cooled as necessary. An NDIR detector (non-dispersive infrared gas detector) can be used to quantify the generated carbon dioxide. The analyzer 1 obtains the detection results of the NDIR detector online and compares them with a calibration curve to determine the total organic carbon concentration of the sample.

[0017] In addition, oxidant B, which has a different oxidizing power from oxidant A, is added to the sample, and the organic matter in the sample is chemically oxidized and decomposed to generate carbon dioxide. The oxidation reaction may be reinforced by heating (100°C or less) or ultraviolet irradiation. The amount of generated carbon dioxide is quantified using an NDIR detector. The analyzer 1 obtains the detection results from the NDIR detector online and compares them with the calibration curve to determine the total organic carbon concentration of the sample.

[0018] The analytical device 1 obtains information on the characteristics (quality) of the organic matter contained in the sample from the difference between the total organic carbon concentration obtained when oxidant A is added to the sample and the total organic carbon concentration obtained when oxidant B is added to the sample.

[0019] Here, the characteristics of organic matter refer to, for example, chemical properties such as molecular weight, structure, functional groups, constituent elements, etc., and physical properties such as solubility, particle size, etc. When an oxidizing agent (A) that can provide sufficient dissociation energy relative to the strength of the chemical bonds of the organic matter is used, the organic matter is decomposed, but when an oxidizing agent (B) with a lower dissociation energy is used, the organic matter cannot be decomposed. Therefore, information on the amount of organic matter with different chemical structures can be obtained from the difference between the total organic carbon concentration when oxidizing agent A is added and the total organic carbon concentration when oxidizing agent B is added.

[0020] Furthermore, for example, highly hydrophobic organic matter has fewer opportunities to come into contact with oxidizing agents in aqueous solutions, and therefore is more susceptible to decomposition by oxidizing agents with stronger oxidizing power. Therefore, information regarding the difference in the hydrophilicity / hydrophobicity of organic matter can be obtained from the difference in total organic carbon concentration obtained using oxidizing agents with different oxidizing powers.

[0021] For example, organic substances with large molecular weights have a three-dimensional structure in aqueous solution, with the hydrophobic parts of their molecular structure facing inward and the hydrophilic parts facing outward (toward the water). Since oxidizing agents can only come into contact with them from the outside, the larger the molecular weight of the organic substance, the longer it takes to decompose it. In other words, information about differences in the molecular weight of organic substances can be obtained from the difference in total organic carbon concentration obtained using oxidizing agents with different oxidizing powers.

[0022] The oxidizing agent used is one that does not contain organic carbon and does not generate carbon dioxide upon decomposition. Examples of the oxidizing agent include sodium peroxodisulfate, ozone, oxygen, inorganic acids such as nitric acid, sulfuric acid, and phosphoric acid, persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate, halogen oxides such as sodium hypochlorite, metal oxides such as lead dioxide, bismuth oxide, and gold oxide, and hydrogen peroxide.

[0023] In particular, examples of combinations of oxidizing agents A and B include "sodium peroxodisulfate and hydrogen peroxide" and "sodium peroxodisulfate and sodium hypochlorite." When sodium peroxodisulfate and hydrogen peroxide are used as oxidizing agents A and B, information on the amount of organic matter with different chemical structures can be obtained from the difference in the total organic carbon concentration. When sodium peroxodisulfate and sodium hypochlorite are used as oxidizing agents A and B, information on the amount of organic matter derived from biological metabolites can be obtained from the difference in the total organic carbon concentration.

[0024] The characteristics of organic matter are also related to the removal of organic matter in the water treatment process of the water treatment facility 2, contamination of functional materials, and the activity of biological treatment. Therefore, the analytical device 1 predicts problems in the water treatment facility 2, monitors its status, and controls and determines operating conditions based on the acquired information on the characteristics of organic matter. This allows the water treatment facility 2 to operate stably. The sample may be water to be treated that is supplied to the water treatment facility 2, or treated water after treatment in the water treatment facility 2. For example, when the analytical device 1 acquires information on an increase in the amount of organic matter derived from biological metabolites as the characteristics of organic matter, it performs control such as increasing the amount of flocculant added in the flocculation treatment of the water treatment facility 2.

[0025] There are no particular restrictions on the type of sample. By adopting a wet oxidation method and strengthening the oxidizing power, it is possible to apply it to environmental water from rivers and lakes, industrial wastewater, etc. The sample is acidified and aerated with pure air that does not contain carbon dioxide, a pretreatment that removes inorganic carbon from the sample, and then the above-mentioned measurement is performed.

[0026] The oxidative decomposition of organic matter and quantification of carbon dioxide when oxidant A is added and the oxidative decomposition of organic matter and quantification of carbon dioxide when oxidant B is added may be performed using the same TOC measurement device or different TOC measurement devices.

[0027] As shown in Figure 2, a conductivity meter may be used to quantify carbon dioxide. The total organic carbon concentration is calculated from the change in the conductivity of the sample before the addition of the oxidizing agent and the conductivity of the sample after the oxidative decomposition of organic matter. Carbon dioxide may also be quantified using both a conductivity meter and an NDIR detector. Quantifying carbon dioxide using multiple types of detection devices allows for the use of multiple control indicators.

[0028] As shown in Figure 3, organic matter in a sample may be oxidatively decomposed using a catalyst (and ultraviolet irradiation). The catalyst may be any catalyst capable of oxidizing organic or inorganic matter contained in the sample. Examples of catalysts that can be used include those containing metals such as iron, manganese, cobalt, chromium, nickel, tungsten, copper, silver, gold, platinum, magnesium, aluminum, zinc, silicon, tin, yttrium, zirconium, niobium, molybdenum, palladium, and titanium, or their oxides, alloys, or composite oxides thereof, as catalytically active components. The organic matter in the sample is oxidatively decomposed into carbon dioxide by the high oxidizing power achieved by the photocatalytic effect of the catalyst and ultraviolet light.

[0029] The analytical device 1 obtains information on the characteristics of organic matter from the difference between the total organic carbon concentration obtained by oxidative decomposition using an oxidizing agent and the total organic carbon concentration obtained by oxidative decomposition using a photocatalytic effect. This method is suitable for obtaining information on the difference between hydrophilicity and hydrophobicity as a characteristic of organic matter.

[0030] As shown in Figure 4, a wet oxidation TOC analyzer and a catalytic combustion TOC analyzer may be used to obtain information on the characteristics of organic matter from the difference in the total organic carbon concentration measured by each TOC analyzer. A catalytic combustion TOC analyzer injects a sample into a combustion tube and burns the organic matter in the sample at high temperatures (650-1200°C) to produce carbon dioxide.

[0031] By calculating the difference between the total organic carbon concentration measured by a wet oxidation TOC analyzer and that measured by a catalytic combustion TOC analyzer, information mainly about solubility can be obtained as a characteristic of organic matter. This is because the wet oxidation method is a homogeneous reaction in an aqueous solution, whereas the catalytic combustion method can oxidize and decompose all organic matter in an aqueous solution, so the amount of particulate (undissolved) organic matter is reflected in the difference in the measured total organic carbon concentration.

[0032] A wet oxidation TOC measuring device may be used to obtain information on the characteristics of organic matter from the difference between the total organic carbon concentration obtained by adding an oxidizing agent and irradiating a sample with ultraviolet light to oxidatively decompose the organic matter in the sample and generate carbon dioxide, and the total organic carbon concentration obtained by irradiating a sample with ultraviolet light without adding an oxidizing agent to oxidatively decompose the organic matter in the sample and generate carbon dioxide. The presence or absence of an oxidizing agent is suitable for obtaining information on chemical bonds as a characteristic of organic matter, because the chemical bond dissociation of various organic matter affects the ultraviolet wavelength.

[0033] In this embodiment, it is possible to change the oxidation conditions simply by changing the presence or absence of an oxidizing agent and the type of oxidizing agent. By applying oxidizing agents with different oxidizing powers, it is also possible to finely adjust the oxidizing power.

[0034] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application No. 2023-188708, filed on November 2, 2023, and is incorporated by reference in its entirety.

[0035] 1. Analytical equipment 2. Water treatment equipment

Claims

1. An organic matter analysis system comprising: a measurement device that adds an oxidizing agent to a sample, decomposes organic matter through chemical oxidation to generate carbon dioxide, and detects the carbon dioxide; and an analysis device that obtains the detection results of the measurement device and calculates the total organic carbon concentration of the sample using the detection results, wherein the analysis device obtains information about the characteristics of the organic matter based on the difference in total organic carbon concentration calculated when an oxidizing agent is added or when different types of oxidizing agent are added.

2. The organic matter analysis system according to claim 1, wherein the characteristics of the organic matter include at least one of molecular weight, structure, functional group, constituent elements, solubility, and particle size.

3. A water treatment system comprising: a water treatment facility; and the analysis system according to claim 1, wherein the sample is water to be treated which is supplied to the water treatment facility; and the analysis device controls the operating conditions of the water treatment facility based on the acquired information on the characteristics of the organic matter.

4. An organic matter analysis system comprising: a first measuring device that adds an oxidizing agent to a sample, decomposes organic matter in the sample by chemical oxidation to generate carbon dioxide, and detects the generated carbon dioxide; a second measuring device that injects the sample into a combustion tube, combusts the organic matter in the sample to generate carbon dioxide, and detects the generated carbon dioxide; and an analyzing device that calculates a first total organic carbon concentration of the sample using the detection result of the first measuring device, calculates a second total organic carbon concentration of the sample using the detection result of the second measuring device, and obtains information on characteristics of the organic matter based on the difference between the first total organic carbon concentration and the second total organic carbon concentration.

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