JP2007083186A - Water treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water treatment system which can optimize an ozone injection rate, an oxidation promoting agent injection rate, and a ratio of these injection rates, and promptly cope with a water-quality change of water to be treated to enable the suppression of the amount of generated harmful disinfection by-products by using a fluorescence analyzer. <P>SOLUTION: The water to be treated is introduced into water treatment equipment 1; ozone is injected into the water to be treated from ozone injection equipment 2, and an oxidation promoting agent is injected from oxidation promoting agent injection equipment 3 to perform advanced oxidation treatment. The fluorescence intensity of the water to be treated before being introduced into the water treatment equipment 1 is measured by a fluorescence analyzer 4 for the water to be treated; water-quality indexes of the water to be treated are measured by a water-quality indexes measuring device 8, and the fluorescence intensity of the water to be treated, introduced to the water treatment equipment 1 and subjected to the advanced oxidation treatment is measured by a fluorescence analyzer 5 for treated water. A water treatment control device 6 performs injection control based on fluorescence intensity reduction rate determined from the fluorescence intensities measured by the fluorescence analyzer 4 for the water to be treated, and fluorescence analyzer 5 for the treated water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water treatment system for performing accelerated oxidation treatment by injecting ozone and an oxidation promoter into water to be treated.

  In recent years, it has been pointed out that rivers and lakes that are water sources for drinking water contain persistent substances such as humic substances, agricultural chemicals, dioxins, and environmental hormones. Among these substances, there are a large number of substances that are harmful to living organisms but need to be removed from water or decomposed. In addition, there is further pollution on the downstream side of the river, and there are areas where the discharged water from the sewage treatment plant located on the upstream side is used again as raw water for the water purification plant. In these rivers, contamination of various chemical substances such as organochlorine detergents, agricultural chemicals, synthetic detergents and dyes has also been confirmed. Furthermore, it can be said that it is in a situation where sufficient attention is required for pollution of the water environment including tap water sources from leachate from industrial and domestic waste landfills.

  Recently, due to such pollution of the water environment, water quality standards at water treatment plants have been reviewed, and water quality management has become stricter than ever. Against this background, water environment conservation technology, advanced water treatment technology, and advanced sewage treatment technology are being actively developed. Treatment with activated carbon, membrane treatment, ozone treatment, ultraviolet treatment, biology Technology development such as intelligent processing is being carried out.

  Among them, accelerated oxidation treatment (AOP, Advancsd Oxidation Process) is regarded as promising as a treatment capable of performing oxidative decomposition of organic substances at a high rate. This accelerated oxidation treatment is a treatment in which ozone and hydrogen peroxide water, ozone and ultraviolet light, or ozone, hydrogen peroxide water, and ultraviolet light are combined. Many methods have been devised for the control method of ozone, oxidation promoter, and ultraviolet irradiation in the accelerated oxidation treatment. As the oxidation accelerator, hydrogen peroxide water is often used.

  Conventionally, the ozone injection control method in the ozone treatment facility in the water purification plant has been mainly the constant control of dissolved ozone. That is, after ozone is injected, ozone is consumed by the reaction between the injected ozone and the organic substance to be treated. Control that injects ozone so that the concentration is constant is the mainstream. In the case of this control method, even if the quality of the raw water before ozone treatment fluctuates, it is possible to perform ozone injection that decomposes organic substances at a constant rate, and there is an advantage that ozone injection can be performed efficiently.

  However, when the accelerated oxidation treatment is performed, hydrogen peroxide solution or ultraviolet rays are used, so that the injected ozone is decomposed. For this reason, dissolved ozone is not detected, and control by the dissolved ozone concentration becomes difficult. Therefore, when the quality of the raw water changes, ozone may be insufficiently injected or excessively injected, resulting in a case where appropriate treatment cannot be performed.

  Even when dissolved ozone is not detected, ozone decomposed by hydrogen peroxide or ultraviolet light changes to a substance with a higher oxidizing power than ozone called hydroxy radicals (OH radicals). Substances and odorous substances are decomposed.

  In recent years, generation of disinfection by-products in ozone treatment has been taken up as a problem in conventional ozone treatment. Among these disinfection by-products, the presence of carcinogenic and toxic substances has been confirmed, and their concentrations are regulated by water quality standards. Recently, many problems of the carcinogenic substance bromic acid generated by the reaction between ozone and bromide ions have been taken up.

  In the accelerated oxidation treatment, much research on bromic acid generation has been conducted. In the accelerated oxidation treatment, it has been confirmed that the production of bromic acid is suppressed by the reducing action of the added hydrogen peroxide solution. In other words, if accelerated oxidation treatment can be performed at an appropriate ozone injection rate and oxidation accelerator injection rate, organic substances in the water to be treated can be efficiently decomposed, and harmful bromic acid production can be suppressed. It is thought that you can.

  Conventionally, there is a control system that uses the product of dissolved ozone concentration and contact time (commonly known as CT value, C: concentration, T: time) as a control for suppressing the production of bromic acid, a disinfection by-product by ozone treatment. (For example, refer to Patent Document 1). According to this method, when the CT value exceeds a predetermined value, the decomposition operation of the dissolved ozone concentration is started and the production of bromic acid is suppressed. As a means for decomposing dissolved ozone concentration, ultraviolet irradiation or hydrogen peroxide water addition is used.

  This technique is an application of accelerated oxidation treatment. However, with this method, a certain amount of dissolved ozone concentration has already been generated in the range where the CT value is detected, and there is a risk that brominated acid will be generated by this dissolved ozone.

  Also, there is a method in which the TOC (total organic carbon) concentration before and after the treatment is used as a control factor for the ozone injection rate and the oxidation promoter injection rate when performing the accelerated oxidation treatment (see, for example, Patent Document 2). Since the accelerated oxidation treatment also mineralizes organic substances in the treated water, it is certainly effective to monitor the decrease in TOC.

  However, the accelerated oxidation treatment has the effect of making the organic substance inorganic while at the same time reducing the molecular weight of the organic substance and making it easy to decompose and remove the organic substance by biological activated carbon after the ozone treatment. In the case of lowering the molecular weight of this organic substance, the TOC concentration does not change, so it is necessary to add other measuring devices and sensors in order to grasp the progress of the decomposition of the organic substance in the accelerated oxidation treatment.

There is a system in which turbidity and fluorescence intensity are used as indicators of organic matter in the accelerated oxidation treatment, and ultraviolet irradiation is controlled based on the turbidity and fluorescence intensity (see, for example, Patent Document 3). The fluorescence intensity has a high correlation with the concentration of organic substances in water, and well represents the state of decomposition of organic substances in ozone treatment and accelerated oxidation treatment. The fluorescence intensity is characterized by a decrease in the value of both inorganic and low molecular organic substances. The method in Patent Document 3 is described with respect to the ultraviolet irradiation type accelerated oxidation treatment, and there is no description about other methods of injecting the oxidation accelerator.
JP 2000-117274 A JP-A-11-290878 JP 2004-243265 A

  As described above, when treating raw water for sewage, secondary treated water for sewage, industrial effluent or leachate from waste landfill, etc., if accelerated oxidation treatment is performed appropriately, organic substances are decomposed at a high rate. There is an advantage that the production of bromic acid, which is a disinfection by-product, is also suppressed. However, when hydrogen peroxide solution is injected or ultraviolet rays are irradiated, dissolved ozone is consumed, and there is a problem that conventional ozone injection control based on the dissolved ozone concentration becomes difficult. In particular, in a treatment plant where the quality of raw water before ozone treatment is large, a control method is required that determines the injection rate so that ozone injection and oxidation accelerator injection can be performed effectively without excessive or insufficient ozone injection.

  The object of the present invention is to optimize the ozone injection rate and the oxidation promoter injection rate and their injection ratio by using a fluorescence analyzer, and can respond quickly to changes in the quality of the water to be treated. An object of the present invention is to provide a water treatment system capable of suppressing the amount of harmful disinfecting by-product produced.

  The water treatment system of the present invention introduces water to be treated, injects ozone from the ozone injection facility into the water to be treated, and injects an oxidation accelerator from the oxidation accelerator injection facility to perform the accelerated oxidation treatment. A treatment facility, a treated water fluorescence analyzer for measuring the fluorescence intensity of the treated water before being introduced into the water treatment facility, a water quality indicator measuring device for measuring a water quality indicator of the treated water, and the water treatment facility A treated water fluorescence analyzer that measures the fluorescence intensity of the treated water introduced and promoted oxidation treatment, and the fluorescence intensity decrease rate obtained from each fluorescence intensity measured by the treated water fluorescence analyzer and the treated water fluorescence analyzer The ozone injection rate of the ozone injection facility is obtained based on the above, and the optimal injection ratio between the ozone injection rate and the oxidation promoter injection rate is calculated based on the water quality indicator measurement value of the treated water measured by the water quality indicator measuring device. And this is the best That from the injection ratio and the determined ozone injection rate and a water treatment control apparatus for determining the pro-oxidant injection rate of the pro-oxidant injection equipment characterized.

  Moreover, the water treatment system of the present invention introduces water to be treated, injects ozone from the ozone injection facility into the water to be treated, and injects an oxidation accelerator from the oxidation accelerator injection facility to perform the accelerated oxidation treatment. A water treatment facility to be performed, a treated water fluorescence analyzer for measuring the fluorescence intensity of the treated water before being introduced into the water treatment facility, a water quality indicator measuring device for measuring the water quality indicator of the treated water, and The ozone injection rate corresponding to the fluorescence intensity of the water to be treated is preset, the ozone injection rate of the ozone injection facility is obtained based on the fluorescence intensity measured by the fluorescence analyzer for water to be treated, and the water quality indicator measuring device Calculate the optimal injection ratio between the ozone injection rate and the oxidation promoter injection rate based on the measured water quality index measured value of the treated water, and promote the oxidation from the optimal injection ratio and the obtained ozone injection rate. Acid in agent injection equipment A water treatment control apparatus for determining the accelerator injection rate may be configured with a.

  Furthermore, the water treatment system of the present invention introduces water to be treated, injects ozone into the water to be treated from an ozone injection facility, and injects an oxidation accelerator from the oxidation accelerator injection facility to perform accelerated oxidation treatment. The water treatment facility to be performed, the water quality indicator measuring device for measuring the water quality indicator of the treated water before being introduced into the water treatment facility, and the fluorescence intensity of the treated water introduced into the water treatment facility and subjected to the accelerated oxidation treatment A treatment water fluorescence analyzer, a target fluorescence intensity of the treatment water is preset, and the fluorescence intensity measured by the treatment water fluorescence analyzer is the preset fluorescence intensity of the ozone injection facility Obtaining the ozone injection rate and calculating the optimal injection ratio between the ozone injection rate and the oxidation accelerator injection rate based on the measured value of the water quality index of the treated water measured by the water quality index measuring device. And said request Was the ozone injection rate from the pro-oxidant injection equipment prooxidant injection rate water treatment control apparatus for determining a may be configured with.

  In the present invention, the water quality index value measured by the water quality index measuring device is a factor that affects the decomposition characteristics of ozone injected into the water to be treated, pH, water temperature, at least one of alkalinity or pH, An indicator that combines water temperature and alkalinity with the amount of organic substances that are decomposed by ozone in the treated water. At least one of fluorescence intensity, total organic carbon concentration, ultraviolet absorbance, or fluorescence intensity, total organic It is either an index combining carbon concentration and ultraviolet absorbance.

  In the present invention, the water treatment control device is preset with an injection ratio that is a reference between the ozone injection rate of the ozone injection facility and the oxidation accelerator injection rate of the oxidation accelerator injection facility, and is measured by the water quality indicator measurement device. Based on the measured water quality indicator value of the treated water, the optimum injection ratio is calculated by correcting the reference injection ratio.

  Further, in the present invention, an oxidation accelerator measuring means for measuring the concentration of the oxidation accelerator remaining in the treated water after being introduced into the water treatment facility is further provided, and the water treatment control device is the oxidation accelerator measuring means. The injection rate of the oxidation accelerator may be adjusted so that the measured concentration of the oxidation accelerator becomes a preset concentration.

  In the present invention, the fluorescence analyzer uses excitation light having a specific wavelength within the wavelength range of “340 to 350 nm” and also uses fluorescence intensity of the specific wavelength within the wavelength range of “420 to 430 nm”. To do.

  In the present invention, the oxidation accelerator injection facility injects hydrogen peroxide water.

  Furthermore, in the present invention, an ultraviolet irradiator that performs ultraviolet irradiation is further provided in a water tank of a water treatment facility into which ozone is injected, and the water treatment control device is configured to inject hydrogen peroxide water into the water treatment facility. You may make it perform ultraviolet irradiation by an ultraviolet irradiation device.

  According to the present invention, the combination of the ozone injection rate and the oxidation accelerator injection rate is optimized, and even when the dissolved ozone concentration is not detected, the fluorescence intensity decrease rate or the fluorescence intensity before and after the accelerated oxidation treatment is increased. By using the measured value, it is possible to appropriately adjust the ozone injection rate even with respect to changes in the quality of the water to be treated. Furthermore, it is possible to achieve a high decomposing power even for a hardly decomposable substance, and to suppress generation of harmful disinfecting by-product substance bromic acid.

  Hereinafter, an embodiment of a water treatment system according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration of a water treatment system according to the first embodiment. Here, a typical ozone treatment facility in a water purification plant is taken as an example.

  1 is a water treatment facility, and the inside thereof is divided into an ozone contact tank 1a into which ozone is injected and a retention tank 1b for ensuring reaction time. The water treatment facility 1 introduces water to be treated from the upstream side on the left side of the figure, injects ozone from the ozone injection facility 2 into the water to be treated, and injects an oxidation accelerator from the oxidation accelerator injection facility 3. Then, an accelerated oxidation treatment is performed. And it discharges | emits to the downstream of the right side of illustration through the retention tank 1b.

  The ozone injection facility 2 has an ozone generator 7, and an ozone injection rate for the ozone contact tank 1 a of the water treatment facility 1 is controlled by a water treatment controller 6 described later. Moreover, the oxidation promoter injection equipment 3 has an oxidation promoter storage tank, and the injection rate of the oxidation promoter into the ozone contact tank 1a of the water treatment equipment 1 is controlled by the water treatment control device 6 as well. The oxidation accelerator injection facility 3 injects hydrogen peroxide as an oxidation accelerator.

  On the upstream side of the water treatment facility 1, a coagulation sedimentation treatment water tank 10 is installed. The coagulation sedimentation treatment water tank 10 is provided with a fluorescence analyzer 4 and a water quality indicator measuring device 8, and these measured values are input to the water treatment control device 6. The fluorescence analyzer 4 measures the fluorescence intensity of the water to be treated before being introduced into the water treatment facility 1 connected to the downstream side. Therefore, this fluorescence analyzer 4 is called a to-be-treated water fluorescence analyzer. The water quality index measuring device 8 measures a water quality index (details will be described later) of water to be treated that is also introduced into the water treatment facility 1.

  The water treatment facility 1 is also provided with a fluorescence analyzer 5, and the measured value is input to the water treatment controller 6. This fluorescence analyzer 5 measures the fluorescence intensity of treated water introduced into the water treatment apparatus 1 and subjected to accelerated oxidation treatment as will be described later. Therefore, this fluorescence analyzer 5 is called a treated water fluorescence analyzer.

  Here, the fluorescence analyzers 4 and 5 use excitation light having a specific wavelength within a wavelength range of “340 to 350 nm” and use fluorescence intensity of a specific wavelength within a wavelength range of “420 to 430 nm”. To do.

  The water treatment control device 6 inputs each measurement value described above, obtains the ozone injection rate by the ozone injection facility 2 and the injection rate of the oxidation promoter by the oxidation promoter injection facility 3, and these water treatment facilities 1 Control injection into That is, the water treatment control device 6 obtains a fluorescence intensity reduction rate from each fluorescence intensity measured by the to-be-treated water fluorescence analyzer 4 and the treated water fluorescence analyzer 5, and based on this fluorescence intensity reduction rate, an ozone injection facility The ozone injection rate of 2 is obtained. Moreover, based on the water quality index measured value of the water to be treated measured by the water quality index measuring device 8, the optimum injection ratio between the ozone injection rate and the oxidation accelerator injection rate is calculated. And the oxidation promoter injection rate of the oxidation promoter injection equipment 3 is calculated | required from this optimal injection | pouring ratio and the ozone injection rate calculated | required as mentioned above.

  Hereinafter, ozone injection control by the water treatment controller 6 will be described.

  First, the decrease rate of fluorescence intensity is calculated by the following formula (1).

Fluorescence intensity reduction rate = (fluorescence intensity before treatment−fluorescence intensity after treatment) / fluorescence intensity before treatment (1)
In the water treatment control device 6, a set value is set in advance as to what the fluorescence intensity decrease rate of the pre-treatment fluorescence intensity and the post-treatment fluorescence intensity should be achieved by performing the accelerated oxidation treatment. FIG. 2 is a graph showing the correlation between the ozone injection rate and the fluorescence intensity reduction rate in normal ozone treatment. The decrease rate of the fluorescence intensity draws a curve rather than a linear relationship with the ozone injection rate. This is because substances that are easily decomposed by ozone are rapidly decomposed at the initial stage of ozone injection, and then substances that are slowly decomposed are gradually decomposed.

  In order to achieve the purpose of ozone treatment such as reduction of organic substances (trihalomethane formation ability) and removal of mold odor, it is appropriate to reduce the fluorescence intensity by about 70% to 80%. The water treatment control device 6 calculates the target value of the fluorescence intensity after treatment based on the inputted fluorescence intensity before treatment (measured value of the water fluorescence analyzer 4 to be treated) and the set fluorescence intensity decrease rate. . Therefore, the target value of the fluorescence intensity after processing calculated is set as a set value, and the ozone injection rate by the ozone generator 7 is controlled so that the fluorescence intensity after processing (measured value of the treated water fluorescence analyzer 5) becomes the set value. To do.

  In addition, the water treatment control device 6 has a function of calculating the optimum injection ratio of the ozone injection rate and the oxidation accelerator injection rate based on the input of the detection signal of each water quality indicator from the water quality indicator measuring device 8. Usually, when hydrogen peroxide water is injected in the accelerated oxidation treatment, the injection ratio of hydrogen peroxide water: ozone is considered to be 0.3 to 0.5 from the viewpoint of processing efficiency. This is called the standard processing efficiency.

  However, this injection ratio depends on the values of pH, water temperature, and alkalinity, which are factors that affect the reaction characteristics of ozone, and the fluorescence intensity, total organic carbon concentration, and ultraviolet absorbance that correlate with the amount of organic substances to be treated. The optimum injection ratio varies depending on the value of. Therefore, the water treatment control device 6 inputs these water quality indexes, and determines the optimum injection ratio of hydrogen peroxide water: ozone by correcting the standard treatment efficiency by each water quality index, and more Enables efficient accelerated oxidation treatment.

  That is, the water treatment control device 6 is based on the ozone injection rate obtained from the rate of decrease in the fluorescence intensity described above, and the oxidation promoter: optimum ozone injection ratio calculated based on the water quality index before treatment. The injection rate of the oxidation accelerator is obtained and the injection is controlled. That is, even if the ozone injection rate fluctuates, the injection rate of the hydrogen peroxide solution is also adjusted so as to maintain the calculated optimal injection rate.

  Thereby, with respect to the water to be treated introduced into the water treatment facility 1, the ozone injection rate from the ozone injection facility 2 and the oxidation accelerator injection from the oxidation accelerator injection facility 3 can be optimally controlled. That is, the ozone injection rate is adjusted so that the rate of decrease in the fluorescence intensity before and after the accelerated oxidation treatment is constant, so that the inflowing organic substances can be decomposed at a certain rate even under conditions where the dissolved ozone concentration is not detected. Can do. Further, since the optimum injection ratio is calculated based on the water quality index before the treatment, the more efficient accelerated oxidation treatment can be performed. Furthermore, it is possible to decompose a hardly decomposable organic substance by a hydroxy radical generated by adding hydrogen peroxide solution, and to suppress generation of harmful bromic acid.

  In the above description, hydrogen peroxide is used as an example of the oxidation accelerator, but the oxidation accelerator in the present invention is not limited to this. In FIG. 1, the water treatment facility 1 has only one ozone contact tank 1 a into which ozone is injected and a residence tank 1 b provided for securing reaction time. The shape of the facility 1 is not limited to this, and there may be two ponds and three ponds of ozone contact tanks. In this case, the structure is such that an oxidation accelerator is injected into each pond into which ozone is injected.

  Next, a second embodiment shown in FIGS. 3 and 4 will be described. The water treatment system according to the embodiment of FIG. 3 is different only in that the fluorescence analyzer 5 for measuring the fluorescence intensity of the treated water in the water treatment facility 1 shown in FIG. 1 is omitted. This is substantially the same as the first embodiment.

  In the second embodiment shown in FIG. 3, the fluorescence intensity of the water to be treated introduced into the water treatment facility 1 is detected by the fluorescence analyzer 4. The water treatment control device 6 controls the ozone generator 7 based on the detection signal input from the fluorescence analyzer 4. That is, in the water treatment control device 6, the relationship of the ozone injection rate with respect to the fluorescence intensity before treatment is set in advance. FIG. 4 is an example of a characteristic diagram showing a correlation between an ozone injection rate and a fluorescence intensity reduction rate for each fluorescence intensity in the water to be treated before treatment.

  According to FIG. 4, it can be seen that the greater the fluorescence intensity at the entrance, the greater the amount of ozone that is injected to achieve the same rate of decrease in fluorescence intensity. In the water treatment control device 6, a characteristic curve as shown in FIG. 4 is set in accordance with the inputted fluorescence intensity before the treatment. Then, the ozone injection rate is calculated according to the target fluorescence intensity reduction rate, and the ozone generator 7 is controlled based on the calculated ozone injection rate.

  This control method is effective when ozone is injected into treated water with small fluctuations in raw water quality. In addition, the adjustment of the ozone injection rate based on the characteristic curve input in advance and the fluorescence intensity reduction rate has been described here, but the control method is not limited to this, and a feedforward method using the fluorescence intensity before processing as an index. And a control method for controlling the ozone injection rate.

  In addition, the water treatment control device 6 has a function of calculating an optimal injection ratio of the ozone injection rate and the oxidation accelerator injection rate based on the input of detection signals of the respective water quality indicators from the water quality indicator measurement device 8. This calculation method is as described above. That is, in the injection control of the oxidation accelerator, the water treatment control device 6 first obtains the ozone injection rate based on the fluorescence intensity before the treatment described above. Then, the injection rate of the oxidation accelerator is determined by controlling the injection rate based on the obtained ozone injection rate and the optimal hydrogen peroxide water: ozone injection rate calculated based on the water quality index before treatment. .

  Thereby, it is possible to control the ozone injection rate from the ozone injection facility 2 and the oxidation promoter injection from the oxidation promoter injection facility 3 for the water to be treated introduced into the water treatment facility 1.

  In this way, utilizing the fact that the fluorescence intensity before treatment is highly correlated with the amount of organic substance to be treated, the ozone injection rate is determined by the magnitude of the fluorescence intensity before treatment, and the oxidation accelerator is injected accordingly. Also adjust the rate. Here, since the injection ratio of the oxidation promoter is calculated as the optimal injection ratio based on the water quality index before the treatment, more efficient accelerated oxidation treatment can be performed.

  Next, a third embodiment shown in FIGS. 5 and 6 will be described. The embodiment shown in FIG. 5 differs from the first embodiment shown in FIG. 1 in that the fluorescence analyzer 4 that measures the fluorescence intensity of the water to be treated introduced into the water treatment facility 1 is omitted. The rest is substantially the same as FIG.

  In the embodiment shown in FIG. 5, the fluorescence intensity of the treated water after being introduced into the water treatment facility 1 is detected by the fluorescence analyzer 5. The water treatment controller 6 controls the ozone generator 7 based on the detection signal input from the fluorescence analyzer 5. That is, the target value of the fluorescence intensity after processing is set in advance in the water treatment control device 6.

FIG. 6 is an example of a characteristic diagram showing the correlation between the fluorescence intensity after the treatment and the concentration of bromic acid that is a harmful disinfection by-product in the normal ozone treatment. From FIG. 6, it is understood that if the fluorescence intensity after treatment becomes lower than a certain value (limit fluorescence intensity: X ₁ ), that is, if ozone is excessively injected, bromine acid exceeding the regulation value is generated. . In the accelerated oxidation treatment, the production of bromic acid is suppressed by the reduction action of the injected hydrogen peroxide solution, but the point at which most of the organic substances are decomposed and the point at which the production of bromic acid begins coincides to some extent. From FIG. 6, the target value of the fluorescence intensity after the accelerated oxidation treatment can be estimated. Therefore, the water treatment control device 6 sets and sets the fluorescence intensity higher than the fluorescence intensity at which bromic acid generation exceeds the regulation value (fluorescence intensity setting value: X ₂ in FIG. 6) as the target value of the fluorescence intensity after treatment. The ozone injection is controlled using the processed fluorescence intensity as a target value.

  In addition, the water treatment control device 6 has a function of calculating an optimal injection ratio of the ozone injection rate and the oxidation accelerator injection rate based on the input of detection signals of the respective water quality indicators from the water quality indicator measurement device 8. This calculation method is as described above. That is, in controlling the injection of the oxidation accelerator, the water treatment control device 6 first obtains an ozone injection rate for causing the fluorescence intensity after treatment to follow the target value as described above, and this ozone injection rate. Then, the injection rate of the oxidation accelerator is determined and controlled according to the optimal injection ratio of the oxidation promoter: ozone calculated based on the water quality index before treatment. In other words, even if the ozone injection rate changes, the injection rate of the injected oxidation accelerator is also adjusted so that the calculated oxidation promoter: ozone injection ratio is constant.

  Thereby, it is possible to control the ozone injection rate from the ozone injection facility 2 and the oxidation promoter injection from the oxidation promoter injection facility 3 for the water to be treated introduced into the water treatment facility 1.

  Next, a fourth embodiment shown in FIG. 7 will be described. In the water treatment system according to the fourth embodiment, the concentration of the oxidation promoter remaining in the treated water after being introduced into the water treatment facility 1 in each of the embodiments shown in FIG. 1, FIG. 3, and FIG. The only difference is the provision of an oxidation accelerator measuring device 9 for measuring NO, and the others are substantially the same as those of the embodiments shown in FIGS. FIG. 7 shows that the oxidation accelerator measuring device 9 is added to the embodiment shown in FIG.

  In the embodiment of FIG. 7, an ozone injection facility 2 and an oxidation accelerator injection facility 3 are arranged for the water treatment facility 1. The fluorescence intensity of the water to be treated introduced into the water treatment facility 1 is detected by the fluorescence analyzer 4, and the fluorescence intensity of the treated water introduced into the water treatment facility 1 is detected by the fluorescence analyzer 5. The water treatment control device 6 controls the ozone generator 7 based on the detection signal input from the fluorescence analyzer 4 and the fluorescence analyzer 5.

  The method for calculating the ozone injection rate is as described in the embodiment of FIG. The method for calculating the ozone injection rate may be the method for calculating the ozone injection rate in the embodiment shown in FIGS.

  In addition, the water treatment control device 6 receives from the oxidation accelerator measuring device 9 a measured value of the concentration of the oxidation promoter remaining in the treated water after being introduced into the water treatment facility 1. The injection rate of the oxidation accelerator is adjusted so as to keep the concentration of the remaining oxidation accelerator measured by the oxidation accelerator measuring device 9 constant. It is known that the production of bromic acid in the accelerated oxidation treatment using hydrogen peroxide solution starts from the generation of bromic acid after the remaining hydrogen peroxide solution disappears. This is thought to be due to the progress of the bromic acid formation reaction because the reducing action by the hydrogen peroxide solution disappears.

  Thereby, the ozone injection rate from the ozone injection facility 2 is adjusted by the measured values of the fluorescence analyzers 4 and 5 with respect to the water to be treated introduced into the water treatment facility 1, and from the oxidation accelerator injection facility 3. The injection rate of the oxidation accelerator can be controlled based on the measured value of the oxidation accelerator measuring device 9 that measures the concentration of the remaining oxidation accelerator.

  As described above, since the ozone injection rate is adjusted by the measured value of the fluorescence intensity, the organic substance flowing in at a certain rate can be decomposed even under the condition that the dissolved ozone concentration is not detected. Moreover, since the injection ratio of the oxidation accelerator is also injected so as to keep the concentration of the remaining hydrogen peroxide solution constant, it is more efficient while suppressing the production of bromic acid, which is a harmful disinfection by-product. An accelerated oxidation treatment can be performed.

  Next, a fifth embodiment shown in FIG. 8 will be described. In the water treatment system according to the fifth embodiment, ultraviolet rays are injected into the ozone contact tank 1a into which ozone is injected in the water treatment facility 1 in each of the embodiments shown in FIG. 1, FIG. 3, FIG. 5, and FIG. The only difference is that an ultraviolet irradiator 11 that performs irradiation is provided, and the others are substantially the same as those of the embodiments shown in FIGS. 1, 3, 5, and 7. FIG. 8 shows the embodiment shown in FIG. 1 with an ultraviolet irradiator 11 added.

  In the embodiment shown in FIG. 8, an ozone injection facility 2 and an oxidation accelerator injection facility 3 are provided for the water treatment facility 1. The fluorescence intensity of the water to be treated introduced into the water treatment facility 1 is detected by the fluorescence analyzer 4, and the fluorescence intensity of the treated water introduced into the water treatment facility 1 is detected by the fluorescence analyzer 5. The water treatment control device 6 controls the ozone generator 7 based on the detection signal input from the fluorescence analyzer 4 and the fluorescence analyzer 5.

  The method for calculating the ozone injection rate is as described in the embodiment of FIG. Further, the ozone injection rate calculation method may be the ozone injection rate calculation method in the embodiment shown in FIGS. 3 and 5.

  In addition, the water treatment control device 6 has a function of calculating an optimal injection ratio of the ozone injection rate and the oxidation accelerator injection rate based on the input of detection signals of the respective water quality indicators from the water quality indicator measurement device 8. This calculation method is as described in the embodiment shown in FIG. The method of calculating the oxidation accelerator injection rate may be a method adjusted based on the concentration of the remaining oxidation accelerator according to the fourth embodiment described with reference to FIG.

  In the embodiment of FIG. 8, ultraviolet rays are irradiated into the water to be treated by the ultraviolet irradiator 10 that performs ultraviolet irradiation simultaneously with the addition of the oxidation accelerator. Thereby, the accelerated oxidation treatment of ozone + hydrogen peroxide water + ultraviolet light can be performed, and the hard-to-decompose organic substance can be decomposed with high decomposing power.

It is a system configuration figure showing a 1st embodiment of a water treatment system by the present invention. It is a characteristic view which shows the relationship between the ozone injection rate and fluorescence intensity reduction rate in 1st Embodiment same as the above. It is a system configuration figure showing a 2nd embodiment of the present invention. It is a characteristic view which shows the correlation with the ozone injection rate for every fluorescence intensity in to-be-processed water in 2nd Embodiment same as the above, and fluorescence intensity reduction rate. It is a system configuration figure showing a 3rd embodiment of the present invention. It is a characteristic view which shows the correlation with the fluorescence intensity after the process in 2nd Embodiment same as the above, and the bromic acid production | generation density | concentration which is a harmful | toxic disinfection by-product substance. It is a system configuration figure showing a 4th embodiment of the present invention. It is a system configuration figure showing a 5th embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Water treatment equipment 2 Ozone injection equipment 3 Oxidation promoter injection equipment 4 To-be-treated water fluorescence analyzer 5 Treated water fluorescence analyzer 6 Water treatment control device 7 Ozone generator 8 Water quality index measuring device 9 Oxidation promoter measurement device 11 UV irradiation vessel

Claims (9)

A water treatment facility that introduces water to be treated, injects ozone from the ozone injection facility into the water to be treated, and injects an oxidation accelerator from the oxidation accelerator injection facility to perform an accelerated oxidation treatment; and
Fluorescence analyzer for water to be treated for measuring the fluorescence intensity of water to be treated before being introduced into the water treatment facility, a water quality indicator measuring device for measuring the water quality indicator for the water to be treated, and being introduced and promoted in the water treatment facility A treated water fluorescence analyzer that measures the fluorescence intensity of the treated treated water;
The ozone injection rate of the ozone injection facility was obtained based on the fluorescence intensity decrease rate obtained from each fluorescence intensity measured by the treated water fluorescence analyzer and the treated water fluorescence analyzer, and measured by the water quality indicator measuring device. An optimal injection ratio between the ozone injection rate and the oxidation promoter injection rate is calculated based on the measured value of the water quality index of the water to be treated, and the oxidation accelerator injection equipment is calculated from the optimal injection ratio and the obtained ozone injection rate. A water treatment system comprising: a water treatment control device for obtaining an injection rate of the oxidation accelerator. A water treatment facility that introduces water to be treated, injects ozone from the ozone injection facility into the water to be treated, and injects an oxidation accelerator from the oxidation accelerator injection facility to perform an accelerated oxidation treatment; and
A treated water fluorescence analyzer that measures the fluorescence intensity of the treated water before being introduced into the water treatment facility, and a water quality indicator measuring device that measures the water quality indicator of the treated water;
The ozone injection rate corresponding to the fluorescence intensity of the treated water is preset, the ozone injection rate of the ozone injection facility is obtained based on the fluorescence intensity measured by the treated water fluorescence analyzer, and the water quality index measuring device The optimal injection ratio between the ozone injection rate and the oxidation accelerator injection rate is calculated based on the measured water quality index measured by the water, and the oxidation rate is calculated from the optimal injection ratio and the obtained ozone injection rate. A water treatment system comprising: a water treatment control device for obtaining an oxidation accelerator injection rate of the accelerator injection facility. A water treatment facility that introduces water to be treated, injects ozone from the ozone injection facility into the water to be treated, and injects an oxidation accelerator from the oxidation accelerator injection facility to perform an accelerated oxidation treatment; and
A water quality indicator measuring device for measuring a water quality indicator of water to be treated before being introduced into the water treatment facility, and a treated water fluorescence analyzer for measuring the fluorescence intensity of the treated water introduced into the water treatment facility and subjected to accelerated oxidation treatment When,
The target fluorescence intensity of the treated water is set in advance, the fluorescence intensity measured with the treated water fluorescence analyzer is determined as the ozone injection rate of the ozone injection facility that is the preset fluorescence intensity, and the Based on the water quality index measurement value of the water to be treated measured by the water quality index measuring device, the optimal injection ratio between the ozone injection rate and the oxidation accelerator injection rate is calculated, and this optimal injection ratio and the obtained ozone injection rate are calculated. A water treatment control device for obtaining an oxidation accelerator injection rate of the oxidation accelerator injection facility from the water treatment system. The water quality index value measured by the water quality index measuring device is
An index that combines at least one of pH, water temperature, and alkalinity, which is a factor affecting the decomposition characteristics of ozone injected into the water to be treated, or a combination of pH, water temperature, and alkalinity;
An indicator that combines at least one of fluorescence intensity, total organic carbon concentration, and ultraviolet absorbance, or a combination of fluorescence intensity, total organic carbon concentration, and ultraviolet absorbance, which has a correlation with the amount of organic substances decomposed by ozone in the water to be treated The water treatment system according to any one of claims 1 to 3, wherein the water treatment system is any one of the above.   In the water treatment control device, an injection ratio serving as a reference between the ozone injection rate of the ozone injection facility and the oxidation promoter injection rate of the oxidation accelerator injection facility is set in advance, and the water to be treated measured by the water quality indicator measuring device is set. 5. The water treatment system according to claim 1, wherein an optimal injection ratio is calculated by correcting the reference injection ratio based on a water quality index measurement value. Further provided is an oxidation accelerator measuring means for measuring the concentration of the oxidation accelerator remaining in the treated water after being introduced into the water treatment facility,
The water treatment control device adjusts the injection rate of the oxidation accelerator so that the concentration of the oxidation accelerator measured by the oxidation accelerator measuring means becomes a preset concentration. The water treatment system according to any one of 5.   The fluorescence analyzer is characterized by using excitation light having a specific wavelength within a wavelength range of “340 to 350 nm” and using fluorescence intensity at a specific wavelength within a wavelength range of “420 to 430 nm”. The water treatment system according to any one of claims 1 to 6.   The water treatment system according to any one of claims 1 to 7, wherein the oxidation accelerator injection facility injects hydrogen peroxide water. An ultraviolet irradiator that irradiates ultraviolet rays in a water tank of a water treatment facility into which ozone is injected is further provided.
9. The water treatment according to claim 1, wherein the water treatment control device causes the ultraviolet irradiator to perform ultraviolet irradiation when hydrogen peroxide water is injected into the water treatment facility. system.

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