Treatment accelerator injection system

Abstract

A treatment accelerator injection system according to the present invention comprises a water-to-be-treated measurement unit, an acquisition unit, a treated water quality prediction unit, and an injection rate determination unit. The to-be-treated-water measurement unit acquires water quality information of to-be-treated-water. The acquisition unit acquires at least constraint condition information defining a water quality state of treated water after to-be-treated-water has been subjected to a water treatment, operation condition information during execution of the water treatment, and a plurality of different assumed injection rate values indicating a provisional injection rate of a treatment accelerator for water treatment of the to-be-treated-water. The treated water quality prediction unit acquires, for each assumed injection rate value, a predicted treated water quality value obtained if a treatment accelerator based on each assumed injection rate value is injected into the to-be-treated-water as indicated by the water quality information and a water treatment according to the operation condition information is carried out. The injection rate determination unit determines, as a definitive injection rate value and on the basis of the plurality of predicted treated water quality values and the constraint condition information, an assumed injection rate value corresponding to a predicted treated water quality value that satisfies the constraint condition information.

Description

Treatment accelerator injection system

[0001] Embodiments of the present invention relate to a treatment accelerator injection system.

[0002] Traditionally, ozone gas (hereinafter referred to as ozone) has been used in water treatment fields for tap water, sewage, industrial wastewater, and swimming pool water for purposes such as decomposition of organic matter in water, sterilization, deodorization, and decolorization. Furthermore, to decompose refractory organic matter that cannot be treated by ozone alone, accelerated oxidation treatment (hereinafter sometimes referred to as AOP) has been proposed, which generates highly oxidative OH radicals for oxidative decomposition. Methods for generating OH radicals include irradiating ozone-containing water with ultraviolet light, adding ozone to water containing an oxidation accelerator such as hydrogen peroxide, irradiating hydrogen peroxide-containing water with ultraviolet light, and using hydrogen peroxide, ozone, and ultraviolet light in combination. For example, AOP, which involves injecting ozone and hydrogen peroxide, is attracting attention as a water treatment method for tap water because the risk of bromate formation that may occur when using ozone can be reduced by injecting hydrogen peroxide.

[0003] Japanese Patent Publication No. 2020-124655 Japanese Patent Publication No. 2009-000677

[0004] As mentioned above, the higher the injection volume of hydrogen peroxide, the greater its ability to prevent bromate formation, decompose odor-causing substances and organic matter, and disinfect. On the other hand, operating costs (processing costs) increase with increasing hydrogen peroxide injection volume. Therefore, in AOP (Aided Operation) using ozone and hydrogen peroxide, selecting the ratio (molar ratio) of ozone to hydrogen peroxide injection rates, that is, the appropriate real-time selection of the injection rate of the treatment accelerator, is crucial.

[0005] One of the problems that this invention aims to solve is to provide a treatment accelerator injection system that enables the appropriate selection of the treatment accelerator injection rate in real time.

[0006] The treatment accelerator injection system according to the embodiment comprises a water to be treated measurement unit, an acquisition unit, a treated water quality prediction unit, and an injection rate determination unit. The water to be treated measurement unit acquires water quality information indicating the water quality of the water to be treated. The acquisition unit acquires at least constraint condition information defining the state of the water quality of the treated water after the water to be treated has been treated, operating condition information indicating the operating conditions when the water treatment is performed, and a plurality of different assumed injection rate values ​​indicating the provisional injection rate of the treatment accelerator for the water treatment of the water to be treated. The treated water quality prediction unit acquires a predicted treated water quality value for each assumed injection rate value obtained when the water treatment is performed according to the operating condition information by injecting the treatment accelerator based on each assumed injection rate value into the water to be treated as indicated by the water quality information. The injection rate determination unit determines the assumed injection rate value corresponding to the predicted treated water quality value that satisfies the constraint condition information as the final injection rate value based on the plurality of predicted treated water quality values ​​and the constraint condition information.

[0007] Figure 1 is a block diagram showing the configuration of the treatment accelerator injection system according to the first embodiment. Figure 2 is a block diagram showing the configuration of the treatment accelerator injection system according to the second embodiment. Figure 3 is a block diagram showing the configuration of the treatment accelerator injection system according to the third embodiment. Figure 4 is a block diagram showing the configuration of the treatment accelerator injection system according to the fourth embodiment. Figure 5 is an explanatory diagram showing a complete mixing tank row model in water treatment.

[0008] Hereinafter, embodiments of the treatment accelerator injection system according to the present invention will be described in detail with reference to the attached drawings. The configuration of the embodiments described below, as well as the actions and results (effects) brought about by said configuration, are merely examples and are not limited to the following descriptions. In this specification, ordinal numbers are used solely to distinguish parts and components and do not indicate order or priority.

[0009] (First Embodiment) Figure 1 is a block diagram showing the configuration of the treatment accelerator injection system 10 according to the first embodiment. The treatment accelerator injection system 10 improves the water quality of the treated water after treatment and reduces the operating costs for water treatment by appropriately selecting the injection rate of the treatment accelerator in real time when performing water treatment of the water to be treated (for example, decomposition of organic matter, sterilization, deodorization, decolorization, prevention of bromate formation, etc.).

[0010] The treatment accelerator injection system 10 is a unit that performs simulations to improve the water quality of treated water and reduce operating costs, and includes a water treatment measurement unit 12, an acquisition unit 14, a treated water quality prediction unit 16, an injection rate determination unit 18, etc. It also includes an additive control unit 20, a treatment tank 22, a treatment accelerator addition unit 24, a treated water measurement unit 26, etc., as an actual water treatment unit that realizes actual water treatment.

[0011] The water treatment unit 12 acquires water quality information indicating the water quality of the water to be treated (also called raw water) before water treatment is performed.

[0012] The acquisition unit 14 acquires at least constraint condition information that defines the water quality state of the treated water after water treatment relative to the water to be treated, operating condition information that indicates the operating conditions when the water treatment is performed, and multiple different assumed injection rate values ​​that indicate the provisional injection rate of treatment accelerators (ozone or hydrogen peroxide solution) for the water treatment of the water to be treated.

[0013] The treated water quality prediction unit 16 acquires a predicted treated water quality value for each assumed injection rate, obtained when water treatment is performed according to the operating conditions information by injecting a treatment accelerator based on each assumed injection rate value into the water to be treated, as indicated by the water quality information. The treated water quality prediction unit 16 can also predict at least one of the following: odor substance concentration, organic matter concentration, bromate concentration, dissolved ozone concentration, oxidation accelerator concentration, exhaust ozone concentration, and operating costs for water treatment of the water to be treated.

[0014] The injection rate determination unit 18 determines an assumed injection rate value corresponding to a predicted treated water quality value that satisfies the constraint condition information, based on a plurality of predicted treated water quality values ​​and constraint condition information, as the final injection rate value. The injection rate determination unit 18 may also refer to at least one of the following as operating condition information when determining the final injection rate value: the treatment flow rate of the water to be treated, and the upper and lower limits of the injection rate of the treatment accelerator. The injection rate determination unit 18 may also refer to at least one of the following as constraint condition information when determining the final injection rate value: the concentration of odor substances, organic matter, bromate, dissolved ozone concentration, and ozone concentration in the exhaust gas. The injection rate determination unit 18 may simultaneously determine the optimal injection rates of multiple treatment accelerators (for example, ozone and hydrogen peroxide). The injection rate determination unit 18 may also determine the optimal injection rate of each treatment accelerator at the injection position (treatment accelerator supply position, treatment accelerator supply unit) of the treatment tank 22.

[0015] Furthermore, the additive control unit 20 controls the additive unit (ozone generator, hydrogen peroxide injector, etc.) that adds the treatment accelerator to the water to be treated (raw water or water to be treated in the process of treatment) based on the determined injection rate value. The additive control unit 20 may also predetermine the injection position (treatment accelerator supply position) and whether or not to inject the treatment accelerator based on the prediction results of the treated water quality prediction unit 16.

[0016] The treatment tanks 22 are connected in series, either individually or in groups. The treatment accelerator addition unit 24 has a treatment accelerator supply unit (ozone injection unit or hydrogen peroxide injection unit) located at a predetermined position in the treatment tank 22.

[0017] The treated water measurement unit 26 measures the water quality of the treated water after water treatment has been performed by adding a treatment accelerator based on the determined injection rate value.

[0018] The acquisition unit 14, treated water quality prediction unit 16, injection rate determination unit 18, additive control unit 20, etc., described above may be configured as hardware or implemented in software. Details of each of the above modules will be described later.

[0019] The treatment accelerator injection system 10 of the first embodiment can be applied to the treatment of either tap water or wastewater, but in the first embodiment, an example of its application to the purification treatment of tap water in a water treatment plant will be described.

[0020] The treatment accelerator injection system 10 can use oxidizing agents such as ozone, hydrogen peroxide, and sodium hypochlorite as oxidation accelerators, but the first embodiment shows an example in which ozone and hydrogen peroxide are used as treatment accelerators.

[0021] First, let's describe the configuration of the actual water treatment unit that carries out the water treatment. In Figure 1, an example is shown in which two treatment tanks 22 are arranged in series. The water to be treated (raw water) is introduced into the treatment tank 22 from the water to be treated tank ST or the like. There may be only one treatment tank 22, but usually multiple tanks are connected in series for use. In Figure 1, the water to be treated (raw water) is introduced into the first treatment tank 22A from the water to be treated tank ST, and then the water to be treated in the first treatment tank 22A is introduced into the second treatment tank 22B. In other words, an example is shown in which water treatment is performed in two stages. Note that the first treatment tank 22A may be supplied with water continuously from the piping through which the water to be treated flows, without going through the water to be treated tank ST.

[0022] The treatment tank 22 of the treatment accelerator injection system 10 is exposed to ozone as the water to be treated passes through it. Further downstream from the first treatment tank 22A and the second treatment tank 22B, there may be retention tanks 28 (first retention tank 28A, second retention tank 28B) where the water to be treated from the first treatment tank 22A and the second treatment tank 22B can be temporarily held.

[0023] The treatment tanks 22 (first treatment tank 22A, second treatment tank 22B) are tanks for dissolving ozone in the water to be treated and reacting it with the substances to be treated in the water. The retention tanks 28 (first retention tank 28A, second retention tank 28B) are tanks for temporarily retaining the water to be treated in order to ensure sufficient reaction time (elapsed time) for the ozone dissolved in the water to react with the substances to be treated.

[0024] Ozone injection units 30 (30A, 30B) are installed in the lower part of the treatment tank 22 (first treatment tank 22A, second treatment tank 22B), for example, in the bottom wall. The ozone injection units 30 (30A, 30B) can be any device capable of introducing bubble-like gas (ozone) into the water to be treated, such as a diffuser, diffuser plate, or injector. The bubbles containing ozone injected from the ozone injection units 30 come into contact with the water to be treated as they rise within the treatment tank 22. In the case of the treatment accelerator injection system 10 of the first embodiment, ozone is added to the water to be treated by a multi-stage treatment (for example, a two-stage treatment) with a time difference, so that the ozone reaction treatment in the water to be treated can be carried out more reliably.

[0025] The ozone injection unit 30 (30A, 30B) is connected via piping to the ozone generator 24a contained in the treatment accelerator addition unit 24, and receives a supply of ozone-containing gas, into which ozone is injected (blown) into the water to be treated. The ozone generator 24a can be of a well-known structure, and a detailed explanation is omitted. The ozone generator 24a is electrically connected to the addition control unit 20 and is controlled by the operation of the addition control unit 20. The addition control unit 20 controls the amount of ozone generated by the ozone generator 24a by controlling the amount of power V, and can also make detailed adjustments to the ozone injection amount (ozone concentration) by controlling the opening and closing of the ozone control valves 32 (32A, 32B).

[0026] As described above, in the treatment accelerator injection system 10 of the first embodiment, hydrogen peroxide solution is injected into the water to be treated along with ozone as an oxidation accelerator. The hydrogen peroxide injection unit 34 is installed, for example, immediately before the treatment tank 22 (installed in the flow path piping of the water to be treated) for the purpose of injecting hydrogen peroxide into the water to be treated that flows into the treatment tank 22. The hydrogen peroxide injected into the water to be treated reacts with ozone and other substances in the treatment tank 22. The hydrogen peroxide injection unit 34 may be provided at the top or inside the treatment tank 22.

[0027] The hydrogen peroxide injector 24b, included in the treatment accelerator addition section 24, is connected to the hydrogen peroxide injection section 34 (34A, 34B) via piping. A liquid containing hydrogen peroxide is supplied from the hydrogen peroxide injector 24b and injected into the water to be treated at the hydrogen peroxide injection section 34 (34A, 34B). A well-known configuration of the hydrogen peroxide injector 24b can be used, and a detailed explanation thereof is omitted.

[0028] The additive control unit 20 is connected to the hydrogen peroxide injector 24b and controls the amount of hydrogen peroxide injected from the hydrogen peroxide injection unit 34, as well as making detailed adjustments to the amount of hydrogen peroxide injected (hydrogen peroxide concentration) by controlling the opening and closing of the hydrogen peroxide control valves 36 (36a, 36B).

[0029] The treated water measurement unit 12 is located outside the treatment tank 22 (first treatment tank 22A) and is positioned upstream of the treated water flow path, for example, immediately before the treatment accelerator supply unit (hydrogen peroxide injection unit 34A), in order to measure characteristic values ​​such as the water quality of the treated water.

[0030] The characteristic values ​​of the treated water measured by the treated water measurement unit 12 include the concentration of substances to be treated in the water purification process (odor substance concentration and organic matter concentration in the treated water (raw water)), the concentration of their precursors (bromate precursor concentration), temperature and pH that affect the chemical reaction in the treatment tank 22, and other values ​​such as color, and at least one of these is measured. In the first embodiment, the characteristic values ​​are 2-MIB and geosmin concentrations, which cause odor in tap water, bromide ion concentrations that are precursors to bromate ions, temperature, and pH. Other substances to be treated may be water quality standard items specified by the Water Supply Act. For measuring 2-MIB and geosmin concentrations, for example, gas chromatography / mass spectrometry (GC / MS) can be used. For measuring bromide ion concentrations, for example, a portable water quality meter equipped with an electrode for bromide ions may be used. For measuring organic matter concentrations, for example, fluorescence intensity or ultraviolet absorbance may be used. The information of the measured characteristic values ​​is sent to the injection rate determination unit 18.

[0031] The treated water measuring unit 26 measures at least one of the following in the treated water after water treatment: odor substance concentration, organic matter concentration, and bromate precursor concentration. The treated water measuring unit 26 is installed in the treated water flow path downstream of the treatment tank 22 to measure characteristic values ​​such as water quality of the treated water. In the case of Figure 1, the treated water measuring unit 26 is installed on the outlet side of the second treatment tank 22B (outlet side of the second retention tank 28B). It is desirable that the treated water measuring unit 26 is not installed inside the treatment tank 22 in order to avoid the influence of ozone-containing bubbles. However, if the structure of the treated water measuring unit 26 is capable of suppressing the intrusion of ozone-containing bubbles, it may be installed inside the second treatment tank 22B or the second retention tank 28B. In this case, it can contribute to shortening the flow path of the water to be treated. In addition, the treated water measuring unit 26 may be installed in multiple locations. In this case, it becomes possible to measure the state of the water to be treated in detail during the water treatment process, which can contribute to improving the quality of water treatment. After the characteristic values ​​of the water quality, etc., are measured by the treated water measurement unit 26, the treated water is supplied to the treated water tank EN and temporarily stored. Alternatively, the treated water may be supplied continuously to the transfer piping without going through the treated water tank EN and supplied to other systems or facilities.

[0032] In the treated water measurement unit 26, similar to the raw water measurement unit 12, characteristic values of the treated water are measured. The characteristic values of the treated water are, for example, 2-MIB, Geosmin concentration, bromate ions that may be generated by ozone treatment, temperature, pH, etc. Also, in order to determine whether the ozone injection amount into the raw water is sufficient, the dissolved ozone concentration in the treated water may be measured. In addition to the above-mentioned characteristic values, the treated water measurement unit 26 may measure the water quality standard items defined by the Waterworks Act as characteristic values. For the measurement of 2-MIB and Geosmin concentration, for example, GC / MS is used, and for the measurement of bromate ions, for example, ion chromatography - post-column analysis method (IC-PC) or liquid chromatography tandem mass spectrometry (LC / MS / MS) may be used. For the measurement of the organic matter concentration, for example, fluorescence intensity or ultraviolet absorbance may be used. In the treatment accelerator injection system 10 of the first embodiment, the information on the characteristic values measured by the treated water measurement unit 26 is sent to the acquisition unit 14. By, for example, a driver checking the characteristic values of the treated water acquired by the acquisition unit 14, it is possible to evaluate whether the water treatment by the treatment accelerator injection system 10 has been sufficiently performed and the treated water has reached a predetermined water quality defined by the constraint condition information. Note that this water quality evaluation may be automatically performed by an evaluation system or the like.

[0033] Subsequently, the configuration of the unit that performs simulations to improve the quality of the treated water and reduce the operation cost in the treatment accelerator injection system 10 will be described.

[0034] As described above, the treatment accelerator injection system 10 includes, as a unit that performs simulations, a raw water measurement unit 12 (included in the configuration of the actual water treatment unit), an acquisition unit 14, a treated water quality prediction unit 16, an injection rate determination unit 18, and the like.

[0035] The acquisition unit 14 includes modules such as an operating condition information acquisition unit 14a, a constraint condition information acquisition unit 14b, and an assumed injection rate acquisition unit 14c. The operating condition information acquisition unit 14a, the constraint condition information acquisition unit 14b, and the assumed injection rate acquisition unit 14c acquire operating condition information, constraint condition information, and assumed injection rate values ​​that are entered, for example, by the operator (manager, etc.) of the treatment accelerator injection system 10 through manual input operations. The operating condition information acquisition unit 14a, the constraint condition information acquisition unit 14b, and the assumed injection rate acquisition unit 14c may be configured to automatically acquire operating condition information, constraint condition information, and assumed injection rate values ​​from other systems or higher-level systems.

[0036] Here, the operating condition information acquired by the operating condition information acquisition unit 14a is information indicating the operating conditions when water treatment is performed. The operating condition information includes, for example, initial settings and values ​​that change during operation, such as the flow rate of the water to be treated and the amount of ozone (gas) diffused, constants such as the specifications of the treatment tank 22 (cross-sectional area of ​​the tank, water depth, etc.), the electricity cost of the ozone generator 24a, and constants such as the unit price of hydrogen peroxide injected by the hydrogen peroxide injector 24b.

[0037] The constraint information acquired by the constraint information acquisition unit 14b is a condition value that defines the state of water quality after water treatment for the water to be treated. The constraint information is, for example, a condition that the characteristic values ​​of the treated water quality must satisfy. This constraint information is used in the injection rate determination unit 18 as a condition that the water quality predicted by the treated water quality prediction unit 16 must satisfy. The quantities used as constraint information are, for example, the dissolved ozone concentration in the treated water, the ozone concentration in the exhaust, the minimum injection rate, and G / L (injection gas flow rate / treated water flow rate (gas-liquid volume ratio)). Furthermore, if the items measured as characteristic values ​​of the treated water quality in the treated water measurement unit 26 are of the same type, they can be easily compared with each other, and water quality standard items stipulated in the Water Supply Act, such as bromate concentration, 2-MIB concentration, geosmin concentration, organic matter concentration, and chromaticity, can also be used. The operator may also use the upper or lower limits of these items as constraint conditions.

[0038] The assumed injection rate obtained by the assumed injection rate acquisition unit 14c is an assumed injection rate of a treatment accelerator (for example, ozone or hydrogen peroxide water) for the water treatment of the water to be treated, and a plurality of different assumed values are obtained. The assumed injection rate is, for example, a value obtained by assuming a set of a certain ozone injection rate and a certain hydrogen peroxide injection rate as variables for optimal value search. The assumed injection rate can be determined in advance by tests or the like, and for example, it can be a value obtained by changing the injection rate by a predetermined amount. The assumed injection rate is determined, for example, by a map or the like.

[0039] The injection rate determination unit 18 calculates the optimal ozone injection rate and hydrogen peroxide injection rate for the characteristic values of the water to be treated according to the procedure shown below, and outputs them to the addition control unit 20.

[0040] Specifically, the injection rate determination unit 18 receives the water quality information of the water to be treated measured by the water to be treated measurement unit 12, the operation condition information provided from the operation condition information acquisition unit 14a, the constraint condition information provided from the constraint condition information acquisition unit 14b, and the assumed injection rate provided from the assumed injection rate acquisition unit 14c. First, the injection rate determination unit 18 supplies the water quality information, the operation condition information, the constraint condition information, and a plurality of assumed injection rates to the treated water quality prediction unit 16 to predict the water quality after the AOP treatment (accelerated oxidation treatment). Then, the treated water quality prediction unit 16 returns the predicted treated water quality prediction value to the injection rate determination unit 18. The method for predicting the treated water quality will be described later.

[0041] The injection rate determination unit 18 checks whether the treated water quality prediction value calculated by the treated water quality prediction unit 16 satisfies the constraint conditions defined by the constraint condition information. When the treated water quality prediction value does not satisfy the constraint conditions, in the treated water quality prediction unit 16, the treated water quality prediction value is recalculated using other assumed injection rates, the calculated treated water quality prediction value is returned to the injection rate determination unit 18, and it is checked again whether the constraint conditions are satisfied.

[0042] In the injection rate determination unit 18, if the treated water quality prediction value calculated by the treated water quality prediction unit 16 satisfies the constraints, the unit calculates the operating cost of injecting ozone and hydrogen peroxide into the water to be treated. In other words, the injection rate determination unit 18 works in cooperation with the treated water quality prediction unit 16 to search for a set of ozone and hydrogen peroxide injection rates (injection rate assumption value) that minimizes operating costs while satisfying the constraints. Once a set of ozone and hydrogen peroxide injection rates (injection rate assumption value) that minimizes operating costs while satisfying the constraints is found, the injection rate determination unit 18 determines the found injection rate assumption value as the injection rate determination value and outputs it to the additive control unit 20. The injection rate determination unit 18 may also determine the injection rate determination value such that at least one of the following is minimized as operating costs: for example, minimizing electricity costs and minimizing the injection rate of treatment accelerators (ozone and hydrogen peroxide solution) (amount of treatment accelerator used).

[0043] For optimal value searching in the injection rate determination unit 18, known search methods such as the steepest descent method, Newton method, BFGS method, and Powell method can be used. In the first embodiment, the Powell method is used to search for a set of injection rates (injection rate assumption values) that minimizes operating costs. When the injection rate determination unit 18 first assumes the ozone and hydrogen peroxide injection rates (when selecting the injection rate assumption values ​​to be provided to the treated water quality prediction unit 16), initial values ​​such as an ozone injection rate of 0.5 mg / L and a hydrogen peroxide injection rate of 0.5 mg / L are given. Then, when the treated water quality prediction unit 16 makes predictions from the second time onward, the assumed values ​​of the ozone / hydrogen peroxide injection rates are those calculated by the Powell method that are more likely to minimize operating costs (injection rate assumption values).

[0044] In the first embodiment, for example, the ozone injection cost (electricity cost per unit × power consumption for ozone generation × ozone injection rate / 1000 yen / m²) ３ ]) and the cost of hydrogen peroxide injection (unit price of hydrogen peroxide × hydrogen peroxide injection rate / 1000 [yen / m ３The sum of the above is considered the operating cost. The ozone injection rate and hydrogen peroxide injection rate that minimize the operating cost while satisfying the constraints are then calculated and used as the optimal injection rate for AOP treatment. Note that when determining the optimal injection rate, other indicators may be used in addition to operating cost.

[0045] Meanwhile, the treated water quality prediction unit 16, having obtained characteristic values ​​of the water quality of the water to be treated, constraints and operating conditions, and assumed values ​​for the ozone / hydrogen peroxide injection rate, predicts the water quality of the water to be treated after AOP by calculating chemical reactions, including radical reactions, in the treatment tank 22 using the following method.

[0046] The treated water quality prediction unit 16 can perform calculations using a simulation model called a fully mixed tank row model, as shown in Figure 5. In this case, the treated water portion in the treatment tank 22 is simulated as the liquid phase, and the injected ozone gas portion is simulated as the gas phase. The liquid phase and gas phase regions are divided in the depth direction of the treatment tank 22, and it is assumed that each region is in a state of complete mixing. The unit sequentially calculates the dissolution of ozone from the gas phase to the liquid phase, and the movement of substances between the liquid and gas phase regions, at each time step. Within each region, calculations are performed at each time step to simulate chemical reactions in the treatment tank 22, such as the decomposition of odor-causing substances by ozone. For each of these regions, the concentration of substances at the equilibrium state after a sufficient amount of time has elapsed since the start of the reaction is output as a predicted value for the treated water quality.

[0047] In the first embodiment, the contact tank is assumed to be 6 m deep and divided into 1 m sections in the depth direction. Since the water flow is a downward flow and the ozone flow is an upward flow, the calculation result of the liquid phase calculation in the upper section divided in the depth direction becomes the inflow condition for the lower section, and the calculation result of the lower section becomes the inflow condition for the upper section. For example, in Figure 5, the liquid phase flows from tank 1 to tank 6, and the characteristic value of the water to be treated input from the injection rate determination unit 18 is used as the characteristic value of the inflow side of tank 1. The water quality on the outflow side of tank 6 in the liquid phase is output as the predicted value of the treated water quality. The gas phase flows from tank 6 to tank 1, and the characteristic value related to ozone gas is used as the characteristic value of the inflow side into tank 6. The value of the ozone concentration on the outflow side of tank 1 in the gas phase is output as the exhaust ozone concentration.

[0048] In the first embodiment, as an operation for simulating the chemical reaction in the treatment tank 22, ordinary differential equations are established for each substance including radical intermediates involved in the AOP reaction, and substance concentration calculations are performed within each region. The substances for which concentration calculations are performed are ozone, hydrogen peroxide, OH radicals, O ２－ , OH － , H ＋ , H ２ O (water), O ２ (oxygen), 2-MIB, Geosmin, Br － (bromide ion), BrO ３ － (bromate ion). What is important as the output of the treated water quality prediction unit 16 is the concentrations of ozone, 2-MIB, Geosmin, and bromate ion, but in order to reproduce the chemical reaction in the treatment tank 22 in detail, calculations are also performed for other substances.

[0049] The ordinary differential equation for calculating the substance concentration, for example, in the case of ozone concentration, is: d(liquid-phase ozone concentration) / dt = (concentration change due to the flow at the treatment flow rate Q Ｌ ) + (concentration change due to the flow between regions at the countercurrent ratio r (in the direction opposite to the treatment flow rate) + (concentration change due to the flow between regions at the countercurrent ratio r (in the same direction as the treatment flow rate)) + (concentration change due to the dissolution of ozone from the gas phase) + (concentration change due to the AOP reaction). d(gas-phase ozone concentration) / dt = (concentration change due to the flow at the gas flow rate Q ｇ ) - (concentration change due to the dissolution of ozone into the gas phase). The equation is constructed in this way. The concentration change due to the flow in the liquid phase and countercurrent is formulated as the amount of substance exiting / entering the region per unit time dt. For the concentration change part due to the dissolution of ozone, the overall mass transfer coefficient K Ｌ a ｎ and the distribution coefficient m are used to calculate the dissolution of ozone gas using the gas dissolution rate equation and calculate the amount of ozone dissolved. In the form of an equation, it is as follows. Dissolution rate from the gas phase to the liquid phase = K Ｌ a ｎ (m[gas-phase ozone concentration] - [liquid-phase ozone concentration]). Dissolution rate from the liquid phase to the gas phase = -K Ｌ a ｎ(m[gas phase ozone concentration] - [liquid phase ozone concentration]) For the liquid phase (concentration change due to AOP reaction), the reaction rate equation is derived from the elementary reaction for each substance and substituted into the equation. For each substance involved in the AOP reaction, ordinary differential equations for the liquid and gas phases of tanks 1 to 6 are formulated. The ordinary differential equations for each substance used to calculate the substance concentration are solved using either Euler's method or the Runge-Kutta method.

[0050] The ozone / hydrogen peroxide injection rate is used as the input to the treated water quality prediction unit 16 and the output to the injection rate determination unit 18. Specifically, the ozone injection rate is calculated from the ozone gas concentration and the ozone gas diffusion rate, and the hydrogen peroxide injection rate is calculated from the hydrogen peroxide concentration and the hydrogen peroxide injection rate. Of these, the ozone gas diffusion rate and hydrogen peroxide concentration are often fixed during operation, so the ozone gas concentration is adjusted by the operating power of the ozone generator 24a, and the hydrogen peroxide injection rate is adjusted by changing the hydrogen peroxide injection pump flow rate of the hydrogen peroxide injector 24b. However, if the ozone gas diffusion rate or hydrogen peroxide concentration can be changed, the ozone / hydrogen peroxide injection rate may be adjusted by adjusting them.

[0051] In the first embodiment, the system may also include a mechanism that allows the operator to select whether to input the ozone / hydrogen peroxide injection rate calculated by the injection rate determination unit 18 or the ozone / hydrogen peroxide injection rate calculated by the operator using conventional methods such as an injection rate table to the additive control unit 20.

[0052] When performing water treatment using the treatment accelerator injection system 10 of the first embodiment, a reduction in the operating costs can be expected. A reference example is shown below. For example, when the 2-MIB concentration in the water to be treated is 100 ng / L, the Geosmin concentration is 100 ng / L, and the bromide ion concentration is 10 μg / L, constraints are imposed to reduce the 2-MIB concentration to 10 ng / L or less, the Geosmin concentration to 10 ng / L or less, and the bromate concentration to 10 μg / L or less. In this case, when controlling by adding hydrogen peroxide in an amount five times the molar amount of ozone as shown in Patent Document 1, it is necessary to inject 4.36 mg / L of hydrogen peroxide for the 1.23 mg / L of ozone required for treatment that satisfies the constraints, and the operating cost is 0.63 yen / m ３This is the result. On the other hand, when control is performed using the treatment accelerator injection system 10 shown in this first embodiment, it can be seen that the constraints are satisfied by injecting 1.81 mg / L of hydrogen peroxide for every 1.23 mg / L of ozone. In this case, the operating cost is 0.42 yen / m ３ As a result, it becomes possible to reduce operating costs by approximately 33% compared to the control method described in Patent Document 1.

[0053] As described above, the treatment accelerator injection system 10 in the first embodiment includes a water treatment measurement unit 12, an acquisition unit 14, a treated water quality prediction unit 16, and an injection rate determination unit 18. The water treatment measurement unit 12 acquires water quality information indicating the water quality of the water to be treated (raw water). The acquisition unit 14 acquires at least constraint condition information defining the state of the water quality of the treated water, operating condition information indicating the operating conditions when the water treatment is performed, and a plurality of different assumed injection rate values ​​indicating the provisional injection rate of the treatment accelerator for the water treatment of the water to be treated (raw water). The treated water quality prediction unit 16 acquires a predicted treated water quality value for each assumed injection rate value obtained when the water treatment is performed according to the operating condition information by injecting the treatment accelerator based on each assumed injection rate value into the water to be treated (raw water) indicated by the water quality information. The injection rate determination unit 18 determines an assumed injection rate value corresponding to the predicted treated water quality value that satisfies the constraint condition information as the final injection rate value, based on the plurality of predicted treated water quality values ​​and the constraint condition information. This configuration allows for, for example, real-time selection of the appropriate injection rate of the treatment accelerator, enabling the reduction of operating costs while improving or maintaining the water quality of the treated water, and resulting in a well-balanced treatment accelerator injection system 10.

[0054] (Second Embodiment) Figure 2 is a block diagram showing the configuration of the treatment accelerator injection system 10M according to the second embodiment. The treatment accelerator injection system 10M has substantially the same configuration as the treatment accelerator injection system 10 shown in Figure 1, except that it includes an injection rate correction unit 38 that corrects the confirmed injection value of the treatment accelerator based on the measurement results of the treated water measured by the treated water measurement unit 26. Therefore, in the treatment accelerator injection system 10M, the same reference numerals are used for components that are the same as those in the treatment accelerator injection system 10, and their detailed descriptions are omitted.

[0055] The treated water quality prediction unit 16 described above may contain errors in its prediction results. In this case, even when the injection rate determination unit 18 uses the prediction results from the treated water quality prediction unit 16 to determine the optimal injection rate, the water quality of the treated water discharged from the second treatment tank 22B (second retention tank 28B) may fall outside the range of constraints indicated in the constraint information. For example, the water quality may be inferior to the water quality (target value) specified in the constraints. In other words, there may be insufficient treatment stress. Conversely, the water quality may be too high compared to the water quality (target value) specified in the constraints. As a result, operating costs may increase.

[0056] Therefore, the injection rate correction unit 38 acquires constraint information from the constraint information acquisition unit 14b and actual water quality information of the treated water from the treated water measurement unit 26, and compares the two. Then, based on the comparison results, the injection rate correction unit 38 calculates a correction value to correct the final injection rate value determined by the injection rate determination unit 18. For example, if the comparison between the constraint information and the water quality information of the treated water determines that the water treatment effect of the treated water is insufficient, the injection rate correction unit 38 generates a correction value that increases the injection rate of the treatment accelerator determined by the injection rate determination unit 18. Conversely, if the comparison between the constraint information and the water quality information of the treated water determines that the water treatment effect of the treated water is excessive, the injection rate correction unit 38 generates a correction value that decreases the injection rate of the treatment accelerator determined by the injection rate determination unit 18. In other words, the injection rate correction unit 38 provides feedback based on the water quality information of the treated water and corrects the injection rate provided to the additive control unit 20 using the final injection rate value determined by the injection rate determination unit 18 and the correction value calculated by the injection rate correction unit 38 in the injection rate change unit 40. The injection rate correction unit 38 can obtain a correction value for correcting the final injection rate by referring to a map or the like that defines correction values ​​based on the difference between the treated water and the constraint conditions. The map can be created in advance through testing or the like.

[0057] By directly correcting the determined injection rate in the injection rate correction unit 38, the water quality of the treated water can be brought closer to the constraint conditions (target value) without changing the determined injection rate through the cooperation of the injection rate determination unit 18 and the treated water quality prediction unit 16, as described above. Furthermore, when the injection rate correction unit 38 corrects the determined injection rate through feedback processing, the treatment time can be shortened compared to when the injection rate determination unit 18 and the treated water quality prediction unit 16 cooperate to change the determined injection rate. As a result, even if the water quality of the water to be treated (raw water) fluctuates, the injection rate of the treatment accelerator can be changed quickly, improving the ability to follow water quality fluctuations. Note that since the ozone injection rate and hydrogen peroxide injection rate cannot be adjusted separately via the feedback path using the injection rate correction unit 38, it is assumed that the injection rate determination unit 18 first determines the optimal combination of ozone injection rate and hydrogen peroxide injection rate values ​​and their molar ratio, and then, in fine-tuning using the feedback path, the ratio of the ozone injection rate and hydrogen peroxide injection rate is fixed and feedback control is performed.

[0058] Thus, the treatment accelerator injection system 10M of the second embodiment further includes an injection rate correction unit 38 that corrects the confirmed injection value of the treatment accelerator based on the measurement results of the treated water. With this configuration, for example, the water quality of the treated water can be brought closer to the constraint conditions (target value) quickly and easily.

[0059] (Third Embodiment) Figure 3 is a block diagram showing the configuration of the treatment accelerator injection system 10N according to the third embodiment. The treatment accelerator injection system 10N has substantially the same configuration as the treatment accelerator injection system 10 shown in Figure 1, except that it includes a constraint condition changing unit 42 that can change the constraint condition information acquired by the constraint condition information acquisition unit 14b based on the measurement results of the treated water measured by the treated water measurement unit 26. Therefore, in the treatment accelerator injection system 10N, the same reference numerals are used for components that are the same as those in the treatment accelerator injection system 10, and their detailed descriptions are omitted.

[0060] The constraint information acquired by the constraint information acquisition unit 14b may be a fixed value determined by, for example, the operator's experience or past operating conditions. In this case, even if water treatment is performed based on the optimal injection rate determined through the cooperation of the injection rate determination unit 18 and the treated water quality prediction unit 16, the water quality of the treated water discharged from the second treatment tank 22B (second retention tank 28B) may fall outside the range of constraints indicated by the constraint information. For example, the water quality may be inferior to the water quality (target value) specified in the constraints. Conversely, the water quality (target value) may be higher than necessary, leading to increased operating costs.

[0061] Therefore, based on the measurement results of the treated water measured by the treated water measurement unit 26, the constraint condition change unit 42 modifies the constraint condition information acquired by the constraint condition information acquisition unit 14b and corrects the injection rate determination value in the injection rate determination unit 18. For example, if the water quality of the treated water is inferior to the target water quality, the constraint condition change unit 42 modifies the constraint condition information to tighten the constraint conditions. As a result, the ozone injection rate and the hydrogen peroxide injection rate are increased, and the water quality of the treated water can be rapidly improved. Conversely, if the water quality of the treated water is of higher quality than the target water quality, the constraint condition information is modified to loosen the constraint conditions. As a result, the ozone injection rate and the hydrogen peroxide injection rate are decreased, and while maintaining the water quality of the treated water at the target value, it is possible to contribute to reducing operating costs (amount of treatment accelerator used).

[0062] Furthermore, in the constraint condition change unit 42, the constraint condition information can be changed by, for example, referring to a map that defines the change values ​​for the constraint condition information based on the difference between the treated water and the constraint conditions, which has been determined in advance through tests, and obtaining the change values ​​for the constraint condition information.

[0063] Furthermore, if the time required for the injection rate determination unit 18 to search for the optimal injection rate is sufficiently short compared to the fluctuations in the water quality of the treated water (raw water), it is possible to easily control the system, including changes in the ozone injection rate and hydrogen peroxide injection rate ratio, by directly feeding back the constraint condition information, which is the input value to the injection rate determination unit 18, based on the water quality of the treated water. As a result, it becomes easier to operate the system using the optimal values ​​for the ozone injection rate and hydrogen peroxide injection rate.

[0064] Thus, the treatment accelerator injection system 10N includes a constraint condition modification unit 42 that modifies the constraint condition information by receiving feedback on the measurement result when the measurement result of the treated water measurement unit 26 falls outside the acceptable constraint range based on the constraint condition information, so that the measurement result falls within the acceptable constraint range based on the modified constraint condition information. With this configuration, for example, if the water quality of the treated water does not meet the target value, the water quality can be easily brought closer to the target value. Also, if the water quality of the treated water is of higher quality than the target value, it is possible to maintain the water quality while contributing to a reduction in operating costs.

[0065] (Fourth Embodiment) Figure 4 is a block diagram showing the configuration of the treatment accelerator injection system 10S according to the fourth embodiment. Note that the treatment accelerator injection system 10S utilizes only the simulation unit of the treatment accelerator injection system 10 shown in Figure 1. In other words, the treatment accelerator injection system 10S can be used to simulate the operating cost and injection rate for the water quality of a given water to be treated (raw water) by using only the part that calculates the optimal injection rate of the treatment accelerator (injection rate determination unit 18, treated water quality prediction unit 16, acquisition unit 14, treated water measurement unit 12). In other words, the treatment accelerator injection system 10S can be used to obtain data when constructing an actual water treatment unit of a water treatment facility (treatment tank 22, etc.) that performs water treatment. That is, the treatment accelerator injection system 10S makes it possible to obtain reference data such as the scale of the water treatment facility and the expected operating cost during operation, as well as reference data when designing the injection capacity of the ozone generator 24a and the hydrogen peroxide injector 24b. The configuration of the treatment accelerator injection system 10S is substantially the same as the simulation unit in the treatment accelerator injection system 10 shown in Figure 1. Therefore, in the treatment accelerator injection system 10S, the same reference numerals are used for components that are the same as those in the treatment accelerator injection system 10, and detailed explanations are omitted.

[0066] The treatment accelerator injection system 10S can be used, for example, to estimate the size of the treatment tank 22 and retention tank 28, and the capacity of the treatment accelerator addition section 24 (ozone generator 24a, hydrogen peroxide injector 24b, etc.) required for operation using the resulting ozone and hydrogen peroxide injection rates, by assuming the water quality of a certain water to be treated (raw water) and performing calculations. It can also perform calculations for the water quality and operating conditions of multiple waters to be treated (raw water) and estimate the operating costs. Therefore, it can be used in design decisions when introducing / updating water treatment equipment, contributing to the optimization of equipment construction, simplification of design, and reduction of workload.

[0067] Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0068] 10, 10M, 10N, 10S Treatment accelerator injection system 12 Water to be treated measurement unit 14 Acquisition unit 16 Water quality prediction unit 18 Injection rate determination unit 20 Addition control unit 22 Treatment tank 22A First treatment tank 22B Second treatment tank 24 Treatment accelerator addition unit 26 Water to be treated measurement unit 28 Retention tank 30 Ozone injection unit 32 Ozone control valve 34 Hydrogen peroxide injection unit 36 ​​Hydrogen peroxide water control valve 38 Injection rate correction unit 40 Injection rate change unit 42 Constraint condition change unit ST Water to be treated tank EN Treatment tank

Claims

1. A treatment accelerator injection system comprising: a water treatment measurement unit that acquires water quality information indicating the water quality of the water to be treated; an acquisition unit that acquires at least constraint information defining the state of the water quality of the treated water after the water treatment of the water to be treated; operating condition information indicating the operating conditions when the water treatment is performed; and a plurality of different assumed injection rate values ​​indicating the provisional injection rate of a treatment accelerator for the water treatment of the water to be treated; a treated water quality prediction unit that acquires a predicted treated water quality value for each of the assumed injection rate values ​​obtained when the water treatment is performed according to the operating condition information by injecting the treatment accelerator based on each of the assumed injection rate values ​​into the water to be treated as indicated by the water quality information; and an injection rate determination unit that determines the assumed injection rate value corresponding to the predicted treated water quality value that satisfies the constraint information as a confirmed injection rate value based on the plurality of predicted treated water quality values ​​and the constraint information.

2. The treatment accelerator injection system according to claim 1, wherein the injection rate determination unit determines the injection rate determination value such that at least one of the operating cost required for the water treatment and the injection rate of the treatment accelerator is minimized.

3. A treatment accelerator injection system according to claim 1 or 2, comprising: an additive control unit that controls an additive unit that adds the treatment accelerator to the water to be treated based on the determined injection rate value; one or more treatment tanks connected in series; a treatment accelerator supply unit positioned at a predetermined location in the treatment tank; and a treated water measuring unit that measures the water quality of the treated water after the water treatment has been performed by adding the treatment accelerator based on the determined injection rate value.

4. The treatment accelerator injection system according to claim 3, further comprising an injection rate correction unit that corrects the confirmed injection value of the treatment accelerator based on the measurement results of the treated water.

5. The treatment accelerator injection system according to claim 1 or claim 2, wherein the water treatment measurement unit measures at least one of the odor substance concentration, organic matter concentration, and bromate precursor concentration of the water treatment.

6. The treatment accelerator injection system according to claim 3, wherein the treated water measuring unit measures at least one of the odor substance concentration, organic matter concentration, and bromate precursor concentration of the treated water.

7. The treatment accelerator injection system according to claim 3, wherein the treated water measuring unit measures the dissolved ozone concentration of the treated water.

8. The treatment accelerator injection system according to claim 1 or claim 2, wherein the treated water quality prediction unit predicts at least one of the following: odor substance concentration, organic matter concentration, bromate concentration, dissolved ozone concentration, oxidation accelerator concentration, exhaust ozone concentration, and the operating cost of the water treatment.

9. The treatment accelerator injection system according to claim 1 or 2, wherein the injection rate determination unit refers to at least one of the treatment flow rate of the water to be treated and the upper and lower limits of the injection rate of the treatment accelerator as operating condition information when determining the final injection rate.

10. The treatment accelerator injection system according to claim 1 or 2, wherein the injection rate determination unit refers to at least one of the following as constraint information when determining the injection rate determination value: the concentration of odorous substances after water treatment, the concentration of organic matter, the concentration of bromate, the concentration of dissolved ozone, and the concentration of ozone in the exhaust.

11. The treatment accelerator injection system according to claim 3, wherein the injection rate determination unit simultaneously determines the optimal injection rate of a plurality of treatment accelerators.

12. The treatment accelerator injection system according to claim 11, wherein the injection rate determination unit determines the optimal injection rate of each of the treatment accelerators in the treatment accelerator supply unit of the treatment tank.

13. The treatment accelerator injection system according to claim 3, further comprising a constraint modification unit that modifies the constraint information based on feedback of the measurement result when the measurement result of the treated water measurement unit falls outside the acceptable constraint range based on the constraint information, so that the measurement result falls within the acceptable constraint range based on the modified constraint information.

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