JP7234012B2 - CHLORINING CONTROL DEVICE, CHLORINING CONTROL SYSTEM, CHLORINING CONTROL METHOD AND COMPUTER PROGRAM - Google Patents

Description

Embodiments of the present invention relate to a chlorine injection control device, a chlorine injection control system, a chlorine injection control method, and a computer program.

The domestic water supply law requires disinfection with chlorine, and stipulates that the lower limit of free residual chlorine concentration at water supply points (for example, water taps) is 0.1 mg/L. On the other hand, in the process of generating water to be supplied to consumers (hereinafter referred to as "water purification process"), it is known that chlorine in the water to be treated is decomposed due to various factors and the chlorine concentration in the treated water decreases. ing. Therefore, in the water purification process, it is necessary to adjust the amount of the chlorine agent to be injected into the water to be treated (hereinafter referred to as "the amount of chlorine agent injected") in consideration of the influence of the above factors. However, in the conventional adjustment method, the amount of chlorine decomposed by solar radiation cannot be estimated appropriately, and the injection amount of the chlorine agent cannot be appropriately adjusted in some cases.

JP-A-7-68270 JP-A-6-79284 Japanese Patent No. 4982114

The problem to be solved by the present invention is to provide a chlorine injection control device, a chlorine injection control system, a chlorine injection control method, and a computer program that can more appropriately determine the amount of chlorine to be injected into the water to be treated. .

A chlorine dosing control device of an embodiment has an acquisition unit and an estimation unit. The acquiring unit acquires dose data relating to the dose of ultraviolet rays with which the water to be treated is irradiated in relation to a water purification process having a step of injecting a chlorine agent into the water to be treated. The estimation unit estimates the amount of chlorine contained in the water to be treated that has been decomposed in the process based on the dose data.

2 is a diagram showing a specific example of the system configuration of the chlorine injection control system of the first embodiment; FIG. 2 is a block diagram showing a specific example of the functional configuration of the chlorine injection control device of the first embodiment; FIG. FIG. 4 is a sequence diagram showing a specific example of processing in which the chlorine injection control system of the first embodiment controls the amount of chlorine agent injected into the water to be treated; The figure which shows the specific example of the system configuration|structure of the chlorine injection control system of 2nd Embodiment. The figure explaining the effect obtained by the chlorine injection control system of 2nd Embodiment. The figure which shows the modification of the chlorine injection control system of 2nd Embodiment. The figure which shows the specific example of the system configuration|structure of the chlorine injection control system of 3rd Embodiment. The figure which shows the modification of the chlorine injection control system of 3rd Embodiment. The figure which shows the specific example of the system configuration|structure of the chlorine injection control system of 4th Embodiment. FIG. 11 is a block diagram showing a specific example of the functional configuration of the chlorine injection control device of the fourth embodiment; The figure which shows the modification of the chlorine injection control system of 4th Embodiment.

Hereinafter, a chlorine injection control device, a chlorine injection control system, a chlorine injection control method, and a computer program according to embodiments will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram showing a specific example of the system configuration of the chlorine injection control system of the first embodiment. For example, the chlorine injection control system 100 shown in FIG. 1 is a system for injecting a chlorine agent into the water to be treated before the solid-liquid separation step in the water purification process. Specifically, FIG. 1 shows solid-liquid sedimentation separation of turbidity in the water to be treated by a coagulant in the process of sending the water to be treated to a receiving well 10, a mixing basin 20, a flocculation basin 30, and a sedimentation basin 40 in this order. Figure 3 shows an implementation of the separation process. In FIG. 1, the solid line arrows represent the flow of the water to be treated, and the broken line arrows represent the flow of information.

Here, the receiving well 10 is a reservoir that stores raw water taken in from a water source such as a river. The raw water that reaches the receiving well 10 is sent to the subsequent mixing basin 20 after staying for a predetermined period of time. The mixing pond 20 is a reservoir for forming fine flocs in the water to be treated by mixing the water to be treated and the coagulant. The water to be treated mixed with the coagulant in the mixing pond 20 is sent to the subsequent floc forming pond 30 .

The flocculation pond 30 is a reservoir for promoting agglomeration of flocs by agitating the water to be treated. The water to be treated that has been sent to the flocculation pond 30 is agitated for a predetermined time and then sent to the sedimentation tank 40 in the subsequent stage. Sedimentation tank 40 is a reservoir for separating suspended matter from the water to be treated by gravity settling of flocs. After the water to be treated sent to the sedimentation basin 40 stays for a predetermined time, the supernatant water is discharged as treated water.

FIG. 1 shows a chlorine injection control system 100 for controlling the injection amount of a chlorine agent (for example, sodium hypochlorite) injected into the water to be treated together with the coagulant in the mixing tank 20 of such a solid-liquid separation process. is shown as an example of the chlorine dosing control system of the embodiment. The chlorine injection control system 100 includes a chlorine injection device 5 for injecting a chlorine agent into the water to be treated in the mixing tank 20, a controller 6 for controlling the injection amount of the chlorine agent by the chlorine injection device 5, and an injection rate for the controller 6. and a chlorine injection control device 7 that outputs a set value of.

The chlorine injection device 5 has a function of injecting a chlorine agent into the water to be treated at a flow rate (hereinafter referred to as "injection flow rate") instructed by the controller 6. FIG.

The controller 6 determines the flow rate of the chlorine agent to be instructed to the chlorinating device 5 based on the flow rate of the raw water flowing into the mixing tank 20 and the set value of the chlorine dosing rate instructed by the chlorinating control device 7. have a function. Further, the controller 6 has a function of instructing the injection operation at the determined injection flow rate to the chlorine injection device 5 .

In the chlorine injection control system 100 shown in FIG. is installed.

The chlorine dosing control device 7 provides data on the injection amount of the chlorine agent (hereinafter referred to as "chlorine agent injection amount data") and dose data on the dose of ultraviolet rays irradiated to the water to be treated (hereinafter referred to as "ultraviolet dose"). , the concentration of residual chlorine in the treated water and its target value. The chlorine dosing control device 7 also has a function of instructing the controller 6 to control the chlorine dosing device 5 at the determined set value of the chlorine dosing rate.

Specifically, the chlorine agent injection amount data is data indicating the current chlorine agent injection amount for the water to be treated. In general, the amount of chlorine in water decomposed by ultraviolet rays varies depending on the chlorine concentration (initial chlorine concentration) at the start of ultraviolet irradiation. Therefore, the chlorine injection control device 7 estimates the amount of chlorine in the water to be treated that is decomposed in the solid-liquid separation process (hereinafter referred to as "chlorine decomposition amount") based on the chlorine agent injection amount data, and the estimated value is Determine the set value of the chlorine injection rate based on

Further, the chlorine injection control device 7 performs feedback control for correcting the set value determined as described above according to the degree of divergence between the target value of the residual chlorine concentration of the treated water and the actual residual chlorine concentration of the treated water. may be performed. For such correction, the chlorine injection control system 100 shown in FIG. A total of 41 are installed. The residual chlorine concentration of the treated water measured by the residual chlorine concentration meter 41 is input to the chlorine injection control device 7 as "treated water data".

FIG. 2 is a block diagram showing a specific example of the functional configuration of the chlorine injection control device 7 of the first embodiment. The chlorine injection control device 7 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, etc., which are connected via a bus, and executes programs. The chlorine injection control device 7 operates a storage unit 71, a chlorine agent injection amount data acquisition unit 72, a dose data acquisition unit 73, a target value input unit 74, a chlorine decomposition amount estimation unit 75, and a set value output unit 76 by executing a program. It functions as a device with All or part of each function of the chlorine injection control device 7 may be realized using hardware such as ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), and FPGA (Field Programmable Gate Array). good. The program may be recorded on a computer-readable recording medium. Computer-readable recording media include portable media such as flexible disks, magneto-optical disks, ROMs and CD-ROMs, and storage devices such as hard disks incorporated in computer systems. The program may be transmitted via telecommunication lines.

The storage unit 71 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device. The storage unit 71 stores various information necessary for the chlorine injection control device 7 to acquire the set value of the chlorine injection rate.

The chlorine agent injection amount data acquisition unit 72 has a function of acquiring chlorine agent injection amount data. For example, the chlorine agent injection amount data acquisition unit 72 includes a communication interface and is configured to acquire chlorine agent injection amount data from another device by communication via the communication interface. The chlorine agent injection amount data acquisition unit 72 stores the acquired chlorine agent injection amount data in the storage unit 71 .

The dose data acquisition unit 73 has a function of acquiring dose data. For example, the dose data acquisition unit 73 includes a communication interface and is configured to acquire dose data from another device by communication via the communication interface. The dose data acquisition unit 73 stores the acquired dose data in the storage unit 71 . The other device that supplies the dose data may be a device included in the chlorine dosing control system 100 or an external system device that is not included in the chlorine dosing control system 100 .

It should be noted that the dose data is desirably data relating to ultraviolet rays in the wavelength band of 280 to 315 nm. This is because ultraviolet rays in the wavelength band of 280 nm or less are absorbed by oxygen and ozone in the atmosphere and do not reach the ground, and the absorption peak of hypochlorous acid by ultraviolet rays is in the wavelength band of 290 to 315 nm. .

The target value input unit 74 is configured using an input device such as a touch panel, mouse and keyboard. Also, the target value input unit 74 may be configured as an external input interface for connecting an external input device to the chlorine injection control device 7 . The target value input unit 74 inputs the target value of the residual chlorine concentration of the treated water, and stores the input target value in the storage unit 71 .

The chlorine decomposition amount estimating unit 75 estimates the amount of chlorine in the water to be treated that is decomposed in the solid-liquid separation process (hereinafter “chlorine decomposition amount”) based on the chlorine agent injection amount data and the dose data stored in the storage unit 71. ) is estimated. The chlorine decomposition amount estimation unit 75 outputs the estimated value of the chlorine decomposition amount to the set value output unit 76 .

The setting value output unit 76 includes a communication interface that communicably connects the chlorine injection control device 7 with the controller 6 . The setting value output unit 76 determines the setting value of the chlorine injection rate to be instructed to the controller 6 based on the estimated value of the chlorine decomposition amount acquired by the chlorine decomposition amount estimation unit 75 . The set value output unit 76 instructs the controller 6 to control the chlorine dosing device 5 at the determined set value of the chlorine dosing rate.

FIG. 3 is a sequence diagram showing a specific example of processing for controlling the amount of chlorine agent injected into the water to be treated by the chlorine injection control system 100 of the first embodiment. Here, for the sake of simplicity, the flow of processing in one control cycle is shown, but in reality, the processing shown in FIG. The amount of chlorine agent to be injected in the mixing tank 20 is adjusted in accordance with changes in the solar radiation situation and the target value of the residual chlorine concentration in the treated water.

First, in the chlorine injection control device 7, the chlorine agent injection amount data acquisition unit 72 and the dose data acquisition unit 73 acquire the chlorine agent injection amount data and the dose data (steps S101 and S102), and the target value input unit 74 Input the target value of the residual chlorine concentration of the treated water (step S103). The obtained chlorine agent injection amount data, dose data, and residual chlorine concentration target value are stored in the storage unit 71 . On the other hand, the controller 6 acquires flow rate data indicating the flow rate of the raw water (step S104). Flow data is acquired by the flow meter 11 .

Subsequently, in the chlorine injection control device 7, the chlorine decomposition amount estimation unit 75 estimates the chlorine decomposition amount in the solid-liquid separation step based on the chlorine agent injection amount data and the dose data stored in the storage unit 71 ( step S105). The chlorine decomposition amount estimation unit 75 outputs the estimated value of the chlorine decomposition amount to the set value output unit 76 . In this case, for example, the chlorine decomposition amount estimator 75 calculates the estimated value of the chlorine decomposition amount using the following equation (1).

D _Cl in the formula (1) represents the amount of chlorine decomposition of the water to be treated in the solid-liquid separation step, and x represents the amount of ultraviolet rays indicated by the dose data. Also, y represents the value of chlorine agent injection amount data (for example, indicating the chlorine agent injection rate). For example, equation (1) may be a relational expression obtained based on the laws of physics, or may be a relational expression estimated based on past data of each variable.

It should be noted that, in the formula (1), based on the current chlorine agent injection rate (or injection amount) indicated by the chlorine agent injection amount data, decomposition in the process (for example, decomposition by the walls of tanks, pipes, pipes, etc.) and a term for correcting errors due to self-decomposition or the like may be included. In addition, the formula (1) may include a term that takes into account information such as the expected flow rate and planned flow rate of the water to be treated flowing into the solid-liquid separation process, and each water tank that realizes the solid-liquid separation process may include a term that takes into account the physical configuration information (eg, volume, etc.) of the .

Subsequently, the setting value output unit 76 determines the setting value of the chlorine injection rate to be instructed to the controller 6 based on the estimated value of the chlorine decomposition amount acquired by the chlorine decomposition amount estimation unit 75 (step S106). The setting value output unit 76 outputs the determined setting value of the chlorine injection rate to the controller 6 (step S107). Here, the set value output unit 76 may appropriately correct the set value determined in step S106 according to the degree of divergence between the current value of the residual chlorine concentration in the treated water indicated by the treated water data and the target value. .

Subsequently, the controller 6 determines the injection flow rate of the chlorine agent to be instructed to the chlorine injection device 5 based on the flow rate data and the setting value of the chlorine injection rate output from the chlorine injection control device 7 (step S108). . For example, the injection flow rate is the product of the set chlorine injection rate and the raw water flow rate. The controller 6 instructs the chlorine injector 5 about the determined injection flow rate of the chlorine agent (step S109). Then, the chlorine injection device 5 injects the chlorine agent into the water to be treated at the inflow flow rate instructed by the controller 6 (step S110).

According to the chlorine dosing control system 100 of the first embodiment configured as described above, the chlorine dosing control device 7 instructs the controller 6 to set the set value of the chlorine dosing rate and the amount of ultraviolet rays irradiated to the water to be treated. By considering and determining, it becomes possible to more appropriately determine the amount of chlorine to be injected into the water to be treated.

Specific examples of dose data used in the chlorine dosing control system 100 of the first embodiment will be described below in the second and third embodiments. Specifically, in the second embodiment, the configuration using the UV index value as dose data will be described, and in the third embodiment, the configuration using the measured value of the UV dosimeter as the dose data will be described.

(Second embodiment)
FIG. 4 is a diagram showing a specific example of the system configuration of the chlorine injection control system 100a of the second embodiment. The chlorine dosing control system 100a shown in FIG. 4 differs from the chlorine dosing control system 100 shown in FIG. 1 in that it has a configuration for acquiring data indicating the UV index value as dose data. Since other configurations are the same as those in FIG. 1, similar configurations are denoted by the same reference numerals as in FIG. 1, and descriptions thereof are omitted here.

The ultraviolet index represents the intensity of ultraviolet rays in a wavelength band that is harmful to humans, and is an index of ultraviolet intensity that is widely used in Japan and overseas. For example, WHO (World Health Organization) recommends taking measures against ultraviolet rays based on this ultraviolet index. Moreover, in Japan, the Japan Meteorological Agency publishes the current value or predicted value of the UV index. Specifically, the UV index is a numerical value obtained by dividing the erythemal UV dose obtained by weighting the UV intensity for each wavelength according to the degree of influence on the human body by 25 (mW/m ² ). By calculating back from the index, the UV intensity for each wavelength can be estimated.

By the way, the decomposition amount of chlorine contained in the water to be treated per unit time is considered to be the amount of hypochlorous acid in the water that reacts with photons in the ultraviolet region contained in sunlight and is decomposed in a unit time. Therefore, in order to estimate the amount of chlorine decomposition, first, the amount of photons in the ultraviolet region is calculated based on the amount of ultraviolet rays. For example, based on the properties of ultraviolet rays shown in the following (1) to (3), the amount of chlorine decomposition is calculated by the following procedure.

(1) The irradiation intensity in the ultraviolet region of the sunlight spectrum varies with wavelength, and the absorption efficiency also varies with wavelength.
(2) Photon absorption efficiency also varies depending on the form ratio (free state or ionic state) of hypochlorous acid in water.
(3) The form ratio of hypochlorous acid varies depending on the pH of the water to be treated.

[Procedure 1] Calculate the intensity Eλ for ultraviolet rays of each wavelength.
The UV index value is a value obtained by multiplying the erythemal UV intensity I _CIE [W/m ² ] (hereinafter referred to as “CIE UV intensity”) defined by the CIE International Commission on Illumination by a predetermined coefficient. , the CIE UV intensity is calculated as the sum of values obtained by multiplying the UV intensity for each wavelength by the CIE action spectral coefficient. On the other hand, it is thought that the intensity of ultraviolet rays is affected by the angle between the sunlight and the ground surface, the amount of clouds, etc., but the shape of the spectral distribution itself does not change, and the intensity of ultraviolet rays at each wavelength is thought to change at the same rate. It is

Therefore, spectral data of ultraviolet rays can be obtained by applying the sum of the ultraviolet intensity of each wavelength represented by the ultraviolet index to the predetermined shape of the spectral distribution. In other words, ultraviolet spectral data can be generated back-calculated from the value of the ultraviolet index. In general, the actual measured values and forecast values for the UV index are announced by meteorological observatories in various places. By generating UV spectrum data based on this information, the UV intensity at each wavelength can be calculated.

[Procedure 2] Calculate the dose Fλ for ultraviolet rays of each wavelength.
To estimate the amount of chlorine decomposed by ultraviolet rays, the amount of ultraviolet rays absorbed by hypochlorous acid in water is required. Therefore, the intensity Eλ [W/m ² ] obtained in Procedure 1 and the irradiation time [sec] of ultraviolet rays are used to calculate the amount of ultraviolet rays Fλ [J/m ² ] for each wavelength. Here, the irradiation time is obtained as the residence time in each reservoir, which is the time during which the water to be treated is exposed to ultraviolet rays.

[Procedure 3] Calculate the form ratio of hypochlorous acid present in the water to be treated.
As described above, the existence ratio (ie, form ratio) of the hypochlorous acid free form HClO and the ionic form ClO ⁻ in the water to be treated changes according to the pH, so the water to be treated stays in the sedimentation tank. The average form ratio of hypochlorous acid during the period can be estimated based on the average value of pH from the time when the water to be treated flows into the sedimentation tank until it reaches the outflow part. In Procedure 3, the concentration of each form is obtained based on the form ratio of hypochlorous acid thus estimated and the injection amount of sodium hypochlorite.

[Procedure 4] Calculate the reaction rate constant Kλ.
The reaction rate constant Kλ is obtained based on the photon efficiency φ, the absorptance ελ, and the photon energy Uλ. Therefore, using the ultraviolet absorptivity and photon energy for each wavelength obtained for each form of hypochlorous acid in Procedure 3, the reaction rate constant for each wavelength for each form is calculated.

[Procedure 5] Calculate the amount of hypochlorous acid decomposed per unit time by ultraviolet rays of each wavelength.
The reaction rate due to ultraviolet rays of each wavelength is obtained by multiplying the amount of ultraviolet rays Fλ of each wavelength obtained in step 2 and the reaction rate constant Kλ for each wavelength of each form obtained in step 4, and the sum of the reaction rates of each wavelength is calculated. Calculate the overall reaction rate for each form by taking. Further, based on the molar chlorine concentration of the water to be treated flowing into the sedimentation basin 40 and the water depth of the sedimentation basin 40, the amount of ultraviolet rays absorbed per unit area and per unit time is obtained, and this value is used within the residence time. Find the total amount of UV light absorbed by Then, the decomposition amount of each form of hypochlorous acid is calculated from the primary reaction formula based on the total amount of absorbed ultraviolet rays and the reaction rate of each form.

The process of determining the amount of ultraviolet rays irradiated to the water to be treated based on the intensity of ultraviolet rays indicated by the ultraviolet index may be performed by the dose data obtaining unit 73 or by the chlorine decomposition amount estimating unit 75. good.

FIG. 5 is a diagram for explaining the effect obtained by the chlorine injection control system 100a of the second embodiment. As shown in FIG. 5, the fluctuation pattern of the amount of solar radiation (global solar radiation) measured by the pyranometer and the fluctuation pattern of the ultraviolet index (UV index) have a rough outline of increasing during the day and decreasing during the night. Although the trend is common, the trend of local increase/decrease differs greatly.

On the other hand, conventionally, the amount of chlorine decomposition is estimated based on the amount of solar radiation, and the corresponding chlorine agent is added to the injection amount determined without considering the influence of solar radiation for correction. Specifically, it calculates the time of sunrise and sunset at that point from the location information and the date, and the altitude in the south. It is performed to estimate the amount of chlorine decomposition while correcting based on.

However, as shown in FIG. 5, the variation pattern of the amount of solar radiation and the variation pattern of the amount of ultraviolet rays do not necessarily match. There is a possibility that the chlorine agent may be injected in an excessively large amount or an excessively small amount with respect to the treated water, and it may be difficult to maintain the residual chlorine concentration of the treated water at the target value.

In contrast, according to the chlorine injection control system 100a of the second embodiment, the chlorine injection control device 7 determines the set value of the chlorine injection rate to be instructed to the controller 6 based on the value of the ultraviolet index. Therefore, it becomes possible to more appropriately determine the amount of chlorine to be injected into the water to be treated.

(Modification)
FIG. 6 is a diagram showing a modification of the chlorine injection control system 100a of the second embodiment. If there is a gap of several hours between the injection of sodium hypochlorite and the start of ultraviolet irradiation, the chlorine decomposition rate is predicted for that period of time before the chlorine injection rate is determined. There is a need. In this case, if the dose data acquisition unit 73 can acquire the prediction data of the UV index, the chlorine decomposition amount estimation unit 75 is configured to predict the chlorine decomposition amount using the prediction data. good too.

In addition, when such prediction data cannot be acquired, the dose data acquisition unit 73 selects a past similar day on which the variation pattern of the UV index is likely to be similar, and makes a prediction based on the dose data of the similar day. It may be configured to generate data. In this case, as shown in FIG. 6, the chlorine injection control system 100a of the modified example may be provided with a database 81 for accumulating historical UV index data.

(Third embodiment)
FIG. 7 is a diagram showing a specific example of the system configuration of the chlorine injection control system 100b of the third embodiment. A chlorine injection control system 100b shown in FIG. 7 differs from the chlorine injection control system 100a shown in FIG. Since other configurations are the same as those in FIG. 1, similar configurations are denoted by the same reference numerals as in FIG. 1, and descriptions thereof are omitted here.

It is desirable that the ultraviolet dosimeter 9 be capable of measuring the dose of ultraviolet rays in the wavelength band of at least 290 to 315 nm. This is because, as described in the first embodiment, the absorption peak of hypochlorous acid by ultraviolet rays is in the wavelength band of 290 to 315 nm.

According to the chlorine injection control system 100b of the third embodiment configured as described above, the chlorine injection control device 7 instructs the controller 6 to set the chlorine injection rate set value based on the measured value of the ultraviolet dose meter 9. , it becomes possible to more appropriately determine the amount of chlorine to be injected into the water to be treated.

Specifically, the amount of ultraviolet rays irradiated to the ground changes greatly due to the slight difference in the presence or absence of clouds that block ultraviolet rays. By estimating the amount of chlorine decomposition using the value, it becomes possible to more accurately determine the required injection amount of the chlorine agent.

It is known that ultraviolet rays in the wavelength band of 290 to 400 nm greatly affect the amount of chlorine decomposition. Therefore, in order to improve the accuracy of estimating the amount of chlorine decomposition, the UV dose meter 9 may be configured to measure the UV dose in the wavelength band of 290 to 400 nm using a Brewer spectrophotometer. In addition, when it is difficult to simultaneously measure the amount of ultraviolet rays in a wide range of wavelengths, the ultraviolet dosimeter 9 measures the amount of ultraviolet rays in the 290 to 315 nm wavelength band (so-called B region) where the absorption peak of hypochlorous acid exists. It may be configured as In this case, the chlorine decomposition amount estimator 75 may be configured to estimate the amount of ultraviolet rays in other wavelength bands using the measurement result. According to such a configuration, since a semiconductor sensor or the like can be used for the ultraviolet dosimeter 9, the estimation accuracy can be maintained at a relatively high level while suppressing complication of the system configuration.

(Modification)
FIG. 8 is a diagram showing a modification of the chlorine injection control system 100b of the third embodiment. If there is a gap of several hours between the injection of sodium hypochlorite and the start of ultraviolet irradiation, the chlorine decomposition rate is predicted for that period of time before the chlorine injection rate is determined. There is a need. In this case, if the dose data acquisition unit 73 can acquire the prediction data of the ultraviolet dose, the chlorine decomposition amount estimation unit 75 is configured to predict the chlorine decomposition amount using the prediction data. good too.

In addition, when such prediction data cannot be acquired, the dose data acquisition unit 73 selects a past similar day on which the variation pattern of the amount of ultraviolet rays is likely to be similar, and makes a prediction based on the dose data of the similar day. It may be configured to generate data. In this case, as shown in FIG. 8, the chlorine injection control system 100b of the modification may be provided with a database 82 for accumulating past data on the amount of ultraviolet rays.

(Fourth embodiment)
FIG. 9 is a diagram showing a specific example of the system configuration of the chlorine injection control system 100c of the fourth embodiment. A chlorination control system 100c shown in FIG. 9 differs from the chlorination control system 100 shown in FIG. The raw water quality meter 12 is a device for measuring the quality of raw water, and supplies data indicating the measured values (hereinafter referred to as "raw water data") to the chlorine dosing controller 7c. Further, the chlorine dosing control device 7c differs from the chlorine dosing control device 7 of the first embodiment in that the raw water data is further used to determine the set value of the chlorine dosing rate to be instructed to the controller 6 . Since other configurations are the same as those in FIG. 1, similar configurations are denoted by the same reference numerals as in FIG. 1, and descriptions thereof are omitted here.

The raw water data may be replaced with other data corresponding to measured values of raw water quality. For example, the raw water data may be replaced with data indicating estimated values, analytical values, etc. of the raw water quality (hereinafter referred to as “analysis data”). may be replaced.

FIG. 10 is a block diagram showing a specific example of the functional configuration of the chlorine injection control device 7c of the fourth embodiment. The chlorination control device 7c differs from the chlorination control device 7 of the first embodiment in that it further includes a raw water data acquisition unit 77 and includes a chlorination amount estimation unit 75c instead of the chlorination amount estimation unit 75. Since other configurations are the same as those in FIG. 2, similar configurations are denoted by the same reference numerals as in FIG. 2, and descriptions thereof are omitted here.

The raw water data acquisition unit 77 has a function of acquiring raw water data. For example, the raw water data acquisition unit 77 includes a communication interface and is configured to acquire raw water data from the raw water quality meter 12 by communication via the communication interface. The raw water data acquisition unit 77 stores the acquired raw water data in the storage unit 71 .

Here, the raw water data is data indicating the water quality index value of raw water that may affect the residual chlorine concentration of the treated water. Indicates the amount of consumed material.

The chlorine decomposition amount estimation unit 75c is different from the chlorine decomposition amount estimation unit in the first embodiment in that the chlorine amount consumed by the chlorine-consuming substance (hereinafter referred to as "chlorine consumption amount") is taken into account in the estimation of the chlorine decomposition amount. different from 75. For example, the chlorine decomposition amount estimation unit 75c calculates the estimated value of the chlorine decomposition amount using the following equation (2).

z in the formula (2) represents the amount of chlorine-consuming substances contained in the raw water. For example, equation (2) may be a relational expression obtained based on physical laws, or a relational expression estimated based on past data of each variable.

Further, for example, the chlorine decomposition amount estimating unit 75c obtains the chlorine consumption amount individually based on the amount of the chlorine-consuming substance, and adds the obtained value to the chlorine decomposition amount estimated based on the formula (1) or the like. , may be determined as an estimate of the final chlorine decomposition rate.

For example, the chlorine decomposition amount D' _Cl estimated by the formula (2) is calculated as the sum of the chlorine decomposition amount _DUV due to ultraviolet rays and the chlorine decomposition amount _DG due to chlorine-consuming substances. In this case, the set value output unit 76 outputs the current value (or planned value) SV ₀ of the chlorine agent injection rate for the water to be treated, and the chlorine decomposition amounts D _UV and _DG estimated based on the equation (2). Based on this, the predicted value RV of the residual chlorine concentration of the treated water is calculated. This predicted value RV is expressed, for example, by the following equation (3).

Subsequently, the set value output unit 76 calculates the chlorine dosing rate SV required to set the predicted value RV to the target value RV ₀ by a method such as convergence calculation, and the chlorine agent at the calculated chlorine dosing rate SV. Instruct the controller 6 to inject.

According to the chlorine dosing control system 100c of the fourth embodiment configured as described above, the chlorine dosing control device 7c instructs the controller 6 to set the set value of the chlorine dosing rate to and the amount of chlorine-consuming substances contained in the water to be treated, the amount of chlorine to be injected into the water to be treated can be determined more appropriately.

(Modification)
FIG. 11 is a diagram showing a modification of the chlorine injection control system 100c of the fourth embodiment. In cases such as when it is known that the amount of chlorine consumed by the chlorine-consuming substance does not change much, the decrease in chlorine at night when there is no ultraviolet irradiation may be used as the chlorine consumption. With such a configuration, it is not necessary to provide the raw water quality meter 12 for measuring the amount of chlorine-consuming substances. can be determined.

In this case, instead of the raw water quality meter 12, the chlorine injection control system 100c of the modification includes, as shown in FIG. A residual chlorine concentration meter 31 is provided. Note that FIG. 11 shows an example in which the residual chlorine concentration meter 31 is provided at the inflow part of the flocculation pond 30, but as long as the effective chlorine concentration can be measured appropriately, the residual chlorine concentration meter 31 is may be provided at any point from the outflow of the flocculating pond 30 to the inflow of the flocculating pond 30 . Further, in this case, as shown in FIG. 11, the chlorine injection control system 100c may be provided with a database 83 for accumulating measured values of the amount of chlorine at night.

According to at least one embodiment described above, a dose data acquisition unit for acquiring dose data relating to the dose of ultraviolet rays irradiated to the water to be treated, in a water purification process having a step of injecting a chlorine agent into the water to be treated; and a chlorine decomposition amount estimating unit for estimating the amount of chlorine contained in the water to be treated that has been decomposed in the above process based on dose data, thereby more appropriately determining the amount of chlorine to be injected into the water to be treated. It is possible to provide a chlorine injection control device, a chlorine injection control system, a chlorine injection control method and a computer program.

The chlorine injection control device in each of the above embodiments is an example of the first control device, and the controller is an example of the second control device.

While several embodiments of the invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, as well as the scope of the invention described in the claims and equivalents thereof.

100, 100a, 100b, 100c... Chlorine injection control system, 10... Receiving well, 11... Flow meter, 12... Raw water quality meter, 20... Mixing pond, 30... Floc forming pond, 31... Residual chlorine concentration meter, 40... Sedimentation Pond 41 Residual chlorine concentration meter 5 Chlorine injection device 6 Controller 7, 7c Chlorine injection control device 71 Storage unit 72 Chlorine agent injection amount data acquisition unit 73 Dose data acquisition unit 74 Target value input unit 75, 75c Chlorine decomposition amount estimator 76 Set value output unit 77 Raw water data acquisition unit 81, 82, 83 Database 9 Ultraviolet dosimeter

Claims (13)

an acquisition unit for acquiring an ultraviolet index as dose data relating to the dose of ultraviolet rays irradiated to the water to be treated, in a water purification process having a step of injecting a chlorine agent into the water to be treated;
an estimating unit for estimating the amount of chlorine contained in the water to be treated , which is the amount of chlorine decomposed in the process , based on the amount of ultraviolet rays for each wavelength obtained based on the dose data;
with
The estimating unit acquires the total dose of ultraviolet rays irradiated to the water to be treated based on the intensity of the ultraviolet rays indicated by the ultraviolet index, and applies the total amount to the spectrum distribution of ultraviolet rays to obtain the ultraviolet rays for each wavelength. to estimate the quantity,
Chlorine dosing controller. The acquisition unit is configured using an ultraviolet dosimeter, and acquires data indicating the measured value of the ultraviolet dosimeter as the dose data.
A chlorine dosing control device according to claim 1. The ultraviolet dosimeter measures the dose of ultraviolet rays in the wavelength band of 290 nm to 315 nm,
3. The chlorine dosing control device according to claim 2. The ultraviolet dosimeter is configured using a Brewer spectrophotometer,
A chlorine dosing control device according to claim 3. The acquisition unit further acquires prediction data indicating a prediction value regarding a dose of ultraviolet rays irradiated to the water to be treated,
The estimation unit predicts the amount of chlorine decomposition based on the prediction data.
A chlorine dosing control device according to any one of claims 1 to 4 . The acquisition unit acquires data indicating a predicted value of the UV index as the predicted data.
A chlorine dosing control device according to claim 5 . The acquisition unit generates the prediction data based on past dose data,
A chlorine dosing control device according to claim 5 or 6 . The acquisition unit further acquires raw water data indicating the amount of chlorine-consuming substances contained in the water to be treated flowing into the water purification process,
The estimating unit estimates a chlorine consumption amount, which is the amount of chlorine in the water to be treated that is consumed by the chlorine-consuming substance in the process, based on the raw water data.
A chlorine dosing control device according to any one of claims 1 to 7 . The acquisition unit further acquires raw water data indicating the amount of chlorine in the water to be treated that has decreased during the night in the process,
The estimating unit estimates, based on the raw water data, a chlorine consumption amount, which is the amount of chlorine in the water to be treated consumed by chlorine-consuming substances contained in the water to be treated in the process.
A chlorine dosing control device according to any one of claims 1 to 7 . A first control device, which is the chlorine dosing control device according to any one of claims 1 to 9 , for determining the dosing rate of chlorine to the water to be treated;
a second control device for controlling the amount of chlorine injected into the water to be treated based on the injection rate determined by the first control device and the flow rate of the water to be treated flowing into the water purification process;
with
wherein the chlorine injection control device determines the injection rate based on the estimated chlorine decomposition amount;
Chlorine dosing control system. 10. The chlorine dosing control device according to claim 8 or 9, wherein the first control device determines the dosing rate of chlorine to the water to be treated;
a second control device for controlling the amount of chlorine injected into the water to be treated based on the injection rate determined by the first control device and the flow rate of the water to be treated flowing into the water purification process;
with
wherein the chlorine injection control device determines the injection rate based on the estimated chlorine decomposition amount and chlorine consumption;
Chlorine dosing control system. a step of obtaining an ultraviolet index as dose data relating to the dose of ultraviolet rays applied to the water to be treated, with respect to a water purification process having a step of injecting a chlorine agent into the water to be treated;
an estimating step of estimating the amount of chlorine contained in the water to be treated , which is the amount of chlorine decomposed in the process , based on the amount of ultraviolet rays for each wavelength obtained based on the dose data;
has
In the estimating step, based on the intensity of ultraviolet rays indicated by the ultraviolet index, the total amount of ultraviolet rays irradiated to the water to be treated is obtained, and the total amount is applied to the spectral distribution of ultraviolet rays, thereby obtaining the ultraviolet rays for each wavelength. to estimate the quantity,
Chlorine injection control method. A computer program for causing a computer to function as the chlorine dosing control device according to any one of claims 1 to 9 .

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