JP2020142184A - Control device, control method and computer program - Google Patents

Abstract

To provide a control device, a control method and a computer program, possible to more appropriately control an amount of powdered activated carbon injected into water to be treated for the purpose of removing a soluble organic matter.SOLUTION: A control device of an embodiment includes a sodium hypochlorite injection control unit, a coagulant injection control unit, and a powdered activated carbon injection control unit. The sodium hypochlorite injection control unit determines an injection rate of sodium hypochlorite in a second treatment based on a quality of raw water that is water to be treated before a first treatment. The coagulant injection control unit determines a coagulant injection rate in a third treatment based on the water quality of the raw water. The powdered activated carbon injection control unit determines an injection rate of a powdered activated carbon in the first treatment based on an ultraviolet absorbance of the raw water and the injection rate of sodium hypochlorite determined by the sodium hypochlorite injection control unit, and the coagulant injection rate determined by the coagulant injection control unit.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to control devices, control methods and computer programs.

The water to be treated (hereinafter also referred to as "raw water") that flows into the water purification plant from rivers, lakes, reservoirs, etc. contains soluble natural organic matter such as fumin (hereinafter referred to as "soluble organic matter"). .. On the other hand, at water purification plants, chemical agents such as sodium hypochlorite are injected into the water to be treated for the purpose of removing and disinfecting metals such as iron and manganese, but raw water containing soluble organic substances is used at the water purification plant. When it flows into the water, disinfection by-products such as trihalomethanes and haloacetic acids are produced by the chemical reaction between the soluble organic substance and the chemical agent. Since these disinfection by-products are carcinogens, it is necessary to suppress their formation by the above chemical reactions.

In many water purification plants, powdered activated carbon is injected into the water to be treated for the purpose of removing this soluble organic matter. In this method for removing soluble organic matter using powdered activated carbon, the injection rate of powdered activated carbon is determined according to the water quality of the water to be treated, and a jar test (also referred to as a beaker test) is used for this determination method. Often. The jar test is a method in which water to be treated is sampled in a plurality of beakers, and different amounts of activated carbon powder are injected into the sampled water to be treated to evaluate the effect of removing soluble organic matter. .. The minimum injection rate of powdered activated carbon is determined based on the injection amount of the beaker that has obtained a good effect in the jar test.

However, in the method of determining the injection rate of powdered activated carbon by the jar test, it is very difficult to appropriately control the injection rate of powdered activated carbon in accordance with the change in the water quality of the water to be treated. This is because it takes time to determine the injection rate by the jar test, and the quality of the water to be treated has often already changed when an appropriate injection rate is obtained. In addition, the actual injection rate used for charging the powdered activated carbon is generally determined as a value that secures a safety margin for the injection rate obtained by the jar test, and the powdered activated carbon is excessively injected. It tends to be. Since powdered activated carbon has a much higher unit price than other chemicals such as flocculants, sulfuric acid, and sodium hypochlorite, excessive injection of powdered activated carbon may lead to an increase in chemical cost. Against this background, there is a demand for a technique capable of suppressing excessive injection of powdered activated carbon and controlling the injection rate of powdered activated carbon to an appropriate injection rate according to changes in the water quality of the water to be treated.

Japanese Unexamined Patent Publication No. 2012-213759

The problem to be solved by the present invention is to provide a control device, a control method and a computer program capable of more appropriately controlling the injection amount of powdered activated carbon injected into the water to be treated for the purpose of removing soluble organic substances. That is.

The control device of the embodiment includes the first treatment of adsorbing the soluble organic matter contained in the water to be treated on the powdered activated carbon in the powdered activated carbon mixing pond, and the metals and ammonia nitrogen contained in the water to be treated in the prechlorination pond. Control of the water treatment system in which the second treatment of oxidizing the water with sodium hypochlorite and the third treatment of coagulating and sedimenting the suspended substance contained in the water to be treated with the coagulant in the coagulant mixing pond are performed in order. It is an apparatus having a sodium hypochlorite injection control unit, a coagulant injection control unit, and a powdered activated carbon injection control unit. The sodium hypochlorite injection control unit determines the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water which is the water to be treated before the first treatment. The coagulant injection control unit determines the coagulant injection rate in the third treatment based on the water quality of the raw water. The powdered activated carbon injection control unit includes the ultraviolet absorbance of the raw water, the injection rate of sodium hypochlorite determined by the sodium hypochlorite injection control unit, and the coagulant determined by the coagulant injection control unit. Based on the injection rate, the injection rate of the powdered activated carbon in the first treatment is determined.

The figure which shows the structural example of the water treatment system in 1st Embodiment. The figure which shows the specific example of the functional structure of the powder activated carbon injection control part in 1st Embodiment. In the first embodiment, a flowchart showing a flow of a process in which a control device determines an injection rate of powdered activated carbon in a powdered activated carbon mixing pond. The figure which shows the knowledge obtained about the correlation between the DOC concentration of the raw water and the ultraviolet absorbance of the raw water in the 1st embodiment. The figure explaining the knowledge obtained about the correlation between the DOC concentration of the filtered water and the ultraviolet absorbance of the filtered water in the 1st embodiment. The figure explaining the knowledge obtained about the correlation between the injection rate of powdered activated carbon and the treatment rate of a soluble organic matter in 1st Embodiment. The figure which shows the experimental result which shows the effect of removing the soluble organic matter by powdered activated carbon and a flocculant in the 1st Embodiment. The figure explaining the knowledge obtained about the correlation between the pH of raw water and the treatment rate of a soluble organic matter in 1st Embodiment. The figure explaining the knowledge obtained about the correlation between the injection rate of sodium hypochlorite, the ultraviolet absorbance of raw water, and the treatment rate of a soluble organic substance in the first embodiment. The figure which shows the structural example of the water treatment system in 2nd Embodiment. The figure which shows the specific example of the functional structure of the powdered activated carbon injection control part in 2nd Embodiment. In the second embodiment, a flowchart showing a flow of a process in which a control device determines an injection rate of powdered activated carbon in a powdered activated carbon mixing pond. The figure which shows the structural example of the water treatment system in 3rd Embodiment. The figure which shows the specific example of the functional structure of the powder activated carbon injection control part in 3rd Embodiment. The flowchart which shows the flow of the process which the control device 80b determines the injection rate of the powdered activated carbon in the powdered activated carbon mixing pond.

Hereinafter, the control device, the control method, and the computer program of the embodiment will be described with reference to the drawings.

(First Embodiment)
FIG. 1 is a diagram showing a configuration example of a water treatment system according to the first embodiment. FIG. 1 shows a rapid sand filter type water treatment system 100 as an example of the water treatment system of the first embodiment. The water treatment system 100 includes a landing well 10, a powdered activated carbon admixture 20, a prechlorine admixture 30, a flocculant admixture 40, a floc forming pond 50, a sedimentation pond 60, and a filtration pond 70. The water treatment system 100 includes a powdered activated carbon injection device 21 that injects powdered activated carbon into the water to be treated in the powdered activated carbon mixing pond 20, and a hypochlorite that injects sodium hypochlorite into the water to be treated in the prechlorite mixing pond 30. The sodium acid injection device 31 and the coagulant injection device 41 for injecting the coagulant into the water to be treated in the coagulant mixing pond 40 are provided. Further, in the water treatment system 100, the injection rate of powdered activated carbon by the powdered activated carbon injection device 21, the injection rate of sodium hypochlorite by the sodium hypochlorite injection device 31, and the injection rate of the coagulant by the coagulant injection device 41 A control device 80 for controlling the above is provided.

Hereinafter, the treatment of adsorbing and removing the soluble organic matter contained in the water to be treated with powdered activated carbon is referred to as the first treatment. Further, the treatment of oxidizing metals such as iron and manganese and ammonia nitrogen contained in the water to be treated with sodium hypochlorite is called the second treatment. The third treatment is a treatment in which suspended substances such as clay, bacteria, and algae contained in the water to be treated are aggregated and settled by a flocculant. In the third treatment, the powdered activated carbon injected in the powdered activated carbon mixing pond 20 is also removed.

The landing well 10 is a reservoir for storing the water to be treated (hereinafter, also referred to as "raw water") flowing into the water treatment system 100. The raw water that has flowed into the landing well 10 is sent to the powdered activated carbon mixing pond 20 in the subsequent stage after staying for a predetermined time. Between the landing well 10 and the powdered activated carbon mixing pond 20, a water quality measuring device 11 for measuring various raw water qualities, a UV (Ultra Violet) measuring device 12 for measuring the ultraviolet absorbance of the raw water, and powdered activated carbon mixing are provided. A flow meter 13 for measuring the flow rate of raw water flowing into the pond 20 (hereinafter referred to as “inflow flow rate”) is installed. Each device of the water quality measuring device 11, the UV measuring device 12, and the flow meter 13 is communicably connected to the control device 80, and transmits the measurement data to the control device 80.

Specifically, the water quality measuring instrument 11 measures the turbidity, alkalinity, water temperature, pH, chlorine requirement, and ammonia concentration as the water quality of the raw water. The water quality measuring device 11 may be configured as one device capable of measuring all of these water qualities, or may be configured as a set of a plurality of devices capable of individually measuring a part of each water quality. ..

The powdered activated carbon mixing pond 20 is a water storage tank for first treating the water to be treated sent from the landing well 10. Specifically, in the powdered activated carbon mixing pond 20, the powdered activated carbon is injected into the water to be treated by the powdered activated carbon injection device 21. The powdered activated carbon injection device 21 includes a driving unit such as a powdered activated carbon storage tank and a pump, and supplies the powdered activated carbon in the storage tank to the powdered activated carbon mixing pond 20 by the operation of the driving unit. The injection amount of the powdered activated carbon is adjusted by the control device 80 controlling the injection rate of the powdered activated carbon injection device 21.

The pre-chlorine mixing pond 30 is a water storage tank for performing a second treatment on the water to be treated sent from the powdered activated carbon mixing pond 20. Specifically, in the pre-chlorine mixing pond 30, sodium hypochlorite is injected into the water to be treated by the sodium hypochlorite injection device 31. The sodium hypochlorite injection device 31 includes a drive unit such as a storage tank for sodium hypochlorite and a pump, and supplies sodium hypochlorite in the storage tank to the prechlorite mixing pond 30 by the operation of the drive unit. .. The injection amount of sodium hypochlorite is adjusted by the control device 80 controlling the injection rate of the sodium hypochlorite injection device 31.

The coagulant mixing pond 40, the floc forming pond 50, and the settling pond 60 are water storage tanks for performing a third treatment on the water to be treated sent from the pre-chlorine mixing pond 30. Specifically, in the flocculant mixing pond 40, the flocculant is injected into the water to be treated by the flocculant injection device 41. The coagulant injection device 41 includes a drive unit such as a coagulant storage tank and a pump, and supplies the coagulant in the storage tank to the coagulant mixing pond 40 by the operation of the drive unit. The injection amount of the flocculant is adjusted by the control device 80 controlling the injection rate of the flocculant injection device 41.

The coagulant used in the third treatment is preferably an aluminum-based coagulant or an iron-based coagulant. For example, examples of the aluminum-based flocculant include compounds such as aluminum sulfate (sulfate band) and polyaluminum chloride (PAC: Poly Aluminum Chloride). Examples of the iron-based flocculant include compounds such as iron chloride, iron sulfate, and polysilica iron. In this embodiment, it is assumed that PAC is used as a flocculant.

Further, the coagulant mixing pond 40 is provided with a stirrer (not shown) for mixing the water to be treated and the coagulant. For example, a flash mixer (rapid stirrer) can be used for this stirrer. When the water to be treated is agitated by the stirrer, suspended substances and powdered activated carbon in the water to be treated are aggregated to form fine flocs. Further, the coagulant mixing pond 40 is provided with a pH measuring device 42 for measuring the pH of the water to be treated (hereinafter, also referred to as “mixed water”) into which the coagulant is injected. The pH measuring device 42 is communicably connected to the control device 80 and transmits measurement data to the control device 80.

The floc forming pond 50 is provided with a stirrer 51 that agitates the water to be treated in order to promote the agglomeration of flocs. For example, a flocurator (slow speed stirrer) can be used for the stirrer 51. After the water to be treated containing the fine flocs formed in the coagulant mixing pond 40 is sent to the floc forming pond 50, the fine flocs in the water to be treated are agglomerated by being stirred by the stirrer 51. Form large flocs. Although FIG. 1 shows an example in which the floc forming pond 50 is provided with three stirrers 51-1 to 51-3, the number of stirrers 51 may be two or less, or four or more. It may be.

The sedimentation reservoir 60 is a reservoir that stores the water to be treated sent from the floc forming reservoir 50 for a predetermined time or longer. In the settling basin 60, the agglomerated flocs settle to the bottom due to gravity settling and are separated from the water to be treated. The sludge settled at the bottom of the settling basin 60 is appropriately withdrawn by a sludge extraction pump (not shown). On the other hand, the supernatant water from which the flocs are separated is sent to the filtration pond 70 in the subsequent stage.

The filtration reservoir 70 is a reservoir that filters the water to be treated sent from the sedimentation reservoir 60. In the filtration pond 70, minute flocs remaining without being separated in the settling pond 60 are separated and removed from the water to be treated by filtration. The filtered water to be treated (filtered water) is discharged or reused as water that has been purified (hereinafter referred to as "treated water").

The control device 80 is based on the measurement data of the water quality measuring device 11, the UV measuring device 12, the flow meter 13 and the pH measuring device 42, and the injection rate of the powdered activated charcoal by the powdered activated charcoal injection device 21 and the sodium hypochlorite injection device 31. The injection rate of sodium hypochlorite and the injection rate of the flocculant by the flocculant injection device 41 are controlled.

Specifically, the control device 80 includes a CPU (Central Processing Unit), a memory, an auxiliary storage device, and the like connected by a bus, and executes a program. The control device 80 functions as a device including a sodium hypochlorite injection control unit 81, a flocculant injection control unit 82, and a powdered activated carbon injection control unit 83 by executing a program. All or a part of each function of the control device 80 may be realized by using hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array). The program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a flexible disk, a magneto-optical disk, a portable medium such as a ROM or a CD-ROM, or a storage device such as a hard disk built in a computer system. The program may be transmitted over a telecommunication line.

The sodium hypochlorite injection control unit 81 determines the injection rate of sodium hypochlorite based on the quality of the raw water. Specifically, the sodium hypochlorite injection control unit 81 determines the injection rate I _{Cl of} sodium hypochlorite based on the chlorine requirement of the raw water or the ammonia concentration. The sodium hypochlorite injection control unit 81 instructs the sodium hypochlorite injection device 31 to perform the injection operation at the determined injection rate, thereby instructing the injection amount of sodium hypochlorite in the prechlorite mixing pond 30. To adjust.

Since the appropriate injection amount of sodium hypochlorite varies depending on the treatment amount of water to be treated, if the inflow flow rate is expected to fluctuate significantly in a short time, the injection amount of sodium hypochlorite is expected. It is also desirable to adjust according to the fluctuation of the inflow flow rate. In this case, the sodium hypochlorite injection control unit 81 may be configured to control the sodium hypochlorite injection device 31 with an injection amount obtained by converting the determined injection rate according to the inflow flow rate. Specifically, sodium hypochlorite injection control unit 81 obtains the flow rate Q _R of the raw water that is measured by the flow meter 13, the determined infusion rate I _Cl and on the basis of the inlet flow Q _R of the raw water The injection amount of sodium hypochlorite can be calculated.

The above method is an example of a method for determining the injection rate of sodium hypochlorite, and the method for determining the injection rate of sodium hypochlorite is not limited to the above method. The method for determining the injection rate of sodium hypochlorite is as long as the injection rate or amount of sodium hypochlorite required for the second treatment (oxidation treatment of metals) is determined according to the quality of the raw water. Any other method may be used, and an appropriate method may be selected according to the configuration, properties, application, etc. of the water treatment system 100.

The coagulant injection control unit 82 determines the coagulant injection rate in the coagulant mixing pond 40 based on the quality of the raw water. Specifically, the coagulant injection control unit 82 sets the coagulant injection rate _IPAC based on the turbidity, alkalinity or water temperature of the raw water and the pH (pH _C ) of the mixed water in the coagulant mixing pond 40. To determine. The coagulant injection control unit 82 adjusts the injection amount of the coagulant in the coagulant mixing pond 40 by instructing the coagulant injection device 41 to perform the injection operation at the determined injection rate.

Since the appropriate injection amount of the coagulant varies depending on the treatment amount of the water to be treated, if the inflow flow rate is expected to fluctuate significantly in a short time, the injection amount of the coagulant also changes in the inflow flow rate. It is desirable to adjust accordingly. In this case, the coagulant injection control unit 82 may be configured to control the coagulant injection device 41 with an injection amount obtained by converting the determined injection rate according to the inflow flow rate. Specifically, the coagulant injection control unit 82 obtains the flow meter 13 is the raw water inlet flow measured by (Q _R), based on the determined infusion rate I _PAC and inlet flow Q _R of the raw water aggregate The injection amount of the agent can be calculated.

The above method is an example of a method for determining the injection rate of the coagulant, and the method for determining the injection rate of the coagulant is not limited to the above method. The method for determining the injection rate of the flocculant is any other method as long as the injection rate or the injection amount of the flocculant required for the third treatment (coagulation treatment of the suspended substance) is determined according to the quality of the raw water. It may be a method, and an appropriate method may be selected according to the configuration, properties, application, etc. of the water treatment system 100.

The powdered activated carbon injection control unit 83 determines the injection rate of powdered activated carbon in the powdered activated carbon mixing pond 20 based on the water quality of the raw water. Specifically, the powdered activated carbon injection control unit 83 injects the pH (pH _R ) of the raw water, the residence time of the water to be treated in the powdered activated carbon mixing pond 20, the ultraviolet absorbance UV _{0 of the} raw water, and sodium hypochlorite. The injection rate I _ACP of powdered activated carbon is determined based on the injection rate I _{Cl of} sodium hypochlorite determined by the control unit 81 and the injection rate I _PAC of the coagulant determined by the coagulant injection control unit 82. To do. The powdered activated carbon injection control unit 83 adjusts the injection amount of the powdered activated carbon in the powdered activated carbon mixing pond 20 by instructing the powdered activated carbon injection device 21 to perform the injection operation at the determined injection rate.

FIG. 2 is a diagram showing a specific example of the functional configuration of the powdered activated carbon injection control unit 83. The powdered activated carbon injection control unit 83 includes a target absorbance determining unit 831, a target processing rate calculation unit 832, and a powdered activated carbon injection rate calculation unit 833.

The target absorbance determining unit 831 has a function of determining a target value of ultraviolet absorbance (hereinafter referred to as “target absorbance”) corresponding to a water quality target value of treated water (that is, filtered water). For example, the water quality target value is represented by the DOC (Dissolved Organic Carbon: concentration of soluble organic carbon) concentration, which is an index value of the amount of soluble organic matter contained in the water to be treated. Specifically, the target absorbance determining unit 831 determines the target absorbance UV _SV corresponding to the target value (target DOC) of the DOC concentration based on the relationship between the ultraviolet absorbance and the DOC concentration described later. The information indicating the target DOC may be stored in the target absorbance determining unit 831 in advance, or may be input to the target absorbance determining unit 831 via an input device such as a keyboard.

The target treatment rate calculation unit 832 has a function of calculating a target value of the treatment rate (hereinafter referred to as “target treatment rate”) corresponding to the water quality target value of the treated water. The treatment rate referred to here is an index value relating to the amount of DOC removed from the raw water. For example, the ratio of the target absorbance UV _SV to the ultraviolet absorbance UV ₀ of the raw water RUV (Remain Ultra Violet) is expressed by the following formula (1). It is defined as.

The powdered activated carbon injection rate calculation unit 833 determines the quality of the treated water based on the injection amount of sodium hypochlorite in the pre-chlorine mixing pond 30, the injection amount of the coagulant in the coagulant mixing pond 40, and the quality of the raw water. It has a function to calculate the injection amount of powdered activated carbon according to the target value.

For example, the powdered activated carbon injection rate calculation unit 833 has an injection rate of sodium hypochlorite I _Cl in the prechlorite mixing pond 30, an injection rate of the flocculant in the coagulant mixing pond 40 I _PAC , and a treatment in the powdered activated carbon mixing pond 20. the residence time of the water t, pH of the raw water _(pH R), and the processing rate RUV, the function _{f 1} that defines the relationship between the injection rate _{I ACP} of powdered activated carbon in the powdered activated carbon mixing basin 20, sodium hypochlorite injection the value of the injection rate I _Cl of sodium hypochlorite, which is determined by the control unit 81, the value of the injection rate I _PAC coagulant determined by coagulant injection control unit 82, the processing in the powdered activated carbon mixing basin 20 By giving the set value of the residence time t of water, the measured value of pH (pH _R ) of raw water, and the value of the target treatment rate RUV determined by the target treatment rate calculation unit 832, the powdered activated carbon mixing pond 20 The injection rate I _ACP of the powdered activated carbon in the above is calculated. In this case, information indicating the function f ₁ is assumed to be previously stored in the powdered activated carbon injection rate calculating section 833.

Since the appropriate injection amount of powdered activated carbon varies depending on the treatment amount of water to be treated, if the inflow flow rate is expected to fluctuate significantly in a short time, the injection amount of powdered activated carbon also fluctuates in the inflow flow rate. It is desirable to adjust accordingly. In this case, the powdered activated carbon injection rate calculation unit 833 may be configured to control the powdered activated carbon injection device 21 with an injection amount obtained by converting the determined injection rate according to the inflow flow rate. In this case, powdered activated carbon injection rate calculating section 833 acquires from the flow meter 13 to measure the inlet flow Q _R of the raw water, determined infusion rate based on the I _ACP and inlet flow of raw water Q _R implantation powdered activated carbon The amount can be calculated.

FIG. 3 is a flowchart showing a flow of processing in which the control device 80 determines the injection rate of the powdered activated carbon in the powdered activated carbon mixing pond. First, the sodium hypochlorite injection control unit 81 determines the injection rate I _{Cl of} sodium hypochlorite based on the water quality of the raw water (step S101). Generally, the injection amount of sodium hypochlorite required for the second treatment (oxidation treatment of metals) is affected by the chlorine requirement of raw water, the ammonia concentration, and the like. Therefore, the sodium hypochlorite injection control unit 81 observes these factors that affect the injection amount, and determines the injection amount of sodium hypochlorite according to the observed value. In the following, as an example, a method in which the sodium hypochlorite injection control unit 81 determines the injection amount of sodium hypochlorite according to the chlorine requirement of the raw water will be described.

For example, sodium hypochlorite injection control unit 81, the chlorine demand Chl _d of the raw water, and the injection rate I _Cl of sodium hypochlorite in the second process, related to the function f ₂ that defines the raw water of by providing a measurement of the chlorine demand Chl _d, calculates the injection rate I _Cl of sodium hypochlorite. In this case, it is assumed that the information indicating the function f ₂ is stored in advance in the sodium hypochlorite injection control unit 81. For example, the function f ₂ is expressed by the following equation (2).

Further, by giving the value of the injection rate I _Cl calculated by Equation (2), the measurement value of the inlet flow rate Q _R of the raw water into the following equation (3), sodium hypochlorite injection amount q _Cl Can be calculated. Incidentally, the function f ₂ is not necessarily a function containing chlorine demand Chl _d variable of the raw water. Function f ₂ is a chlorine demand Chl _d of the raw water, it may be a function including at least one variable of the ammonia concentration of the raw water.

Subsequently, the flocculant injection control unit 82 determines the flocculant injection rate _IPAC based on the water quality of the raw water (step S102). Examples of the water quality of the raw water used when determining the injection rate of the flocculant include turbidity, alkalinity, and water temperature.

For example, coagulant injection control unit 82, the turbidity of the raw water, the alkalinity and temperature, the function f ₃ that defines the pH of the mixed water, the relationship in the flocculant mixing basin 40, the raw water turbidity T _b the measured values, the measured value of alkalinity Alk of raw water, the measurement value of the water temperature T _R of the raw water, the measured value of the pH of the mixed water (pH _C), by providing the injection rate I _PAC coagulant calculate. In this case, it is assumed that stores information indicating a function f ₃ in advance in the coagulant injection control unit 82. For example, the function f ₃ is expressed by the following equation (4).

Moreover, to calculate the value of the injection rate I _PAC calculated by Equation (4), by providing a measure of the inlet flow Q _R of the raw water into the following equation (5), the injection quantity q _PAC coagulant be able to. Note that the function f ₃ is not necessarily a turbidity T _b of the raw water, the alkalinity Alk raw water, the water temperature T _R of the raw water, need not be the function that contains all the variables. The function f ₃ may be a function that includes at least one of these in a variable.

Then, powdered activated carbon injection control unit 83, injection rate and I _Cl of sodium hypochlorite, which is determined by sodium hypochlorite injection control unit 81, injection of the coagulant, which is determined by the coagulant injection controller 82 The injection rate I _ACP of the powdered activated carbon in the powdered activated carbon mixing pond 20 is determined based on the rate I _PAC .

Specifically, first, the powdered activated carbon injection control unit 83 outputs the target DOC value to the target absorbance determining unit 831, and the measured value of the ultraviolet absorbance UV ₀ of the raw water acquired from the UV measuring device 12 is the target processing rate. Output to the calculation unit 832 (step S103). In the first embodiment, ultraviolet rays having a wavelength of about 260 nm are used for measuring the ultraviolet absorbance UV ₀ of raw water. Here, the reason for using ultraviolet rays of the wavelength is that the following new findings regarding the DOC concentration of raw water have been obtained.

FIG. 4 is a diagram showing the findings obtained regarding the correlation between the DOC concentration of raw water and the ultraviolet absorbance of raw water. Further, FIG. 5 is a diagram for explaining the findings obtained regarding the correlation between the DOC concentration of the filtered water and the ultraviolet absorbance of the filtered water. Both FIGS. 4 and 5 show the correlations obtained for UV light with a wavelength of 260 nm. As shown in FIG. 4, there is a strong correlation between the DOC concentration of raw water and the ultraviolet absorbance with respect to ultraviolet rays having a wavelength of 260 nm, and in this case, the correlation between the DOC concentration of raw water and the ultraviolet absorbance can be approximated by a straight line. Was obtained.

Further, as shown in FIG. 5, there is a strong correlation between the DOC concentration of the filtered water and the ultraviolet absorbance with respect to ultraviolet rays having a wavelength of 260 nm. In this case, the correlation between the DOC concentration of the filtered water and the ultraviolet absorbance is determined. We obtained the finding that it can be approximated by a straight line. Based on the correlation that can be approximated by a straight line in this way, it is considered that the DOC concentration of raw water or filtered water can be accurately estimated from the measured value of ultraviolet absorbance.

Based on such a new finding, the target absorbance determining unit 831 in the present embodiment stores in advance the correlation information showing the relationship between the DOC concentration of the filtered water obtained with respect to the ultraviolet rays having a wavelength of 260 nm and the ultraviolet absorbance. The target absorbance is determined based on this correlation information and the value of the target DOC (step S104). For example, when the target DOC value 1 is given to the relationship shown in FIG. 5, the target absorbance determining unit 831 sets the ultraviolet absorbance value of about 0.014 [abs / cm] corresponding to the target DOC value 1. Target Absorbance Determined as UV _SV . The target absorbance determining unit 831 outputs the determined target absorbance value UV _SV to the target processing rate calculation unit 832.

Returning to the description of FIG. Subsequently, the target processing rate calculation unit 832 calculates the target processing rate RUV based on the value of the ultraviolet absorbance UV ₀ of the raw water measured in step S103 and the value of the target absorbance UV _SV determined in step S104. (Step S105). The target processing rate calculation unit 832 outputs the calculated target processing rate RUV value to the powdered activated carbon injection rate calculation unit 833.

Subsequently, powdered activated carbon injection rate calculating section 833, the value of the injection rate I _Cl of sodium hypochlorite, which is calculated in step S101, the value of the injection rate I _PAC of the calculated flocculant in step S102, step Based on the value of the pH (pH _R ) of the raw water measured in S103, the value of the target treatment rate RUV calculated in step S105, and the set value of the residence time t of the water to be treated in the powdered activated carbon mixing pond 20. Then, the injection rate I _ACP of the powdered activated carbon in the powdered activated carbon mixing pond 20 is calculated (step S106).

Specifically, the powdered activated carbon injection rate calculation unit 833 determines the value of the injection rate I _Cl of sodium hypochlorite, the value of the injection rate I _PAC of the flocculant, the set value of the residence time t, and the pH of the raw water. the measured values of (pH _R), the value of the target processing rate RUV, by providing the function _{f 1} of the following formula (6), to calculate the infusion rate _{I ACP} of powdered activated carbon.

This function f ₁ was introduced based on the following new findings regarding the treatment rate of soluble organic matter.

[First finding]
FIG. 6 is a diagram for explaining the findings obtained regarding the correlation between the injection rate of powdered activated carbon and the treatment rate of soluble organic matter. Conventionally, it has been considered that factors such as the quality of raw water and the injection rate of activated carbon in the first treatment have a great influence on the treatment rate of soluble organic matter by powdered activated carbon, and the second treatment and the third treatment after the first treatment It was unknown how the factors involved in the treatment would affect it. On the other hand, as shown in FIG. 6, even if the injection rate of the powdered activated carbon in the first treatment is the same, if the injection rate of the coagulant injected in the third treatment in the subsequent stage changes, it dissolves accordingly. It was found that the treatment rate of sex organic substances also changes.

That is, in the water treatment method in which the first treatment of adsorbing and removing the soluble organic substance with powdered activated carbon and the third treatment of coagulating and precipitating the suspended substance with a coagulant after the first treatment, the first treatment is performed. In addition to the injection amount of powdered activated carbon in the above, it was found that the injection amount of the coagulant in the third treatment in the subsequent stage also affects the removal performance of the soluble organic matter. In other words, it was conventionally thought that soluble organic matter was removed only by powdered activated carbon, but it was found that soluble organic matter can also be removed by agglomeration and sedimentation of suspended substances by a flocculant.

Specifically, as shown in FIG. 6, it can be seen that the higher the injection rate of the coagulant, the lower the treatment rate of the soluble organic matter and the better the removal performance. It is presumed that this is because the soluble organic matter is concentrated on the surface of the powdered activated carbon in the presence of the powdered activated carbon and is removed together with the powdered activated carbon in the coagulation / sedimentation by the coagulant.

FIG. 7 is a diagram showing the experimental results regarding the removal of soluble organic matter by powdered activated carbon and a flocculant. FIG. 7 shows a case where only the powdered activated carbon treatment is performed (CASE-1), a case where only the coagulant treatment is performed (CASE-2), and a case where the coagulant treatment is performed after the powdered activated carbon treatment (CASE-3). The result of the removal rate (= 1-processing rate) of DOC obtained in each case of is shown. In CASE-1, as a result of injecting powdered activated carbon into raw water at an injection rate of 5 mg / L for 1 hour, a removal rate of about 10% was obtained. Further, in CASE-2, as a result of injecting the flocculant into the raw water at an injection rate of 10 mg / L for 1 hour, a removal rate of about 3% was obtained. On the other hand, in CASE-3, as a result of performing the following steps 1 to 5, a removal rate of about 26% was obtained.

[Procedure 1] Inject powdered activated carbon into raw water under the same conditions as CASE-1 (5 mg / L).
[Procedure 2] Rapid stirring (5 minutes) of the water to be treated in which step 1 was performed.
[Procedure 3] A flocculant is injected into the water to be treated in step 2 under the same conditions as CASE-2 (10 mg / L).
[Procedure 4] Slowly agitate the water to be treated in step 3 (25 minutes).
[Procedure 5] Let the water to be treated that has undergone step 4 stand still (30 minutes).

From these results, it was found that when the powdered activated carbon treatment and the coagulant treatment were used in combination, the DOC removal rate was significantly improved as compared with the case where each treatment was performed alone. In general, the injection of the flocculant is intended to remove suspended substances in the water to be treated, not to remove soluble organic matter. However, according to the above findings, since a part of the soluble organic matter in the water to be treated is also removed by the coagulant, the powdered activated carbon is injected by determining the injection rate of the powdered activated carbon in consideration of the removed amount. It is considered that the amount can be reduced from the conventional amount.

[Second finding]
FIG. 8 is a diagram for explaining the findings obtained regarding the correlation between the pH of raw water and the treatment rate of soluble organic matter. As shown in FIG. 8, it was found that the higher the pH of the raw water, the higher the treatment rate of the soluble organic matter, and the lower the removal performance.

[Third finding]
FIG. 9 is a diagram for explaining the findings obtained regarding the correlation between the injection rate of sodium hypochlorite, the ultraviolet absorbance of raw water, and the treatment rate of soluble organic substances. As shown in FIG. 9, it was found that the higher the injection rate of sodium hypochlorite, the lower the treatment rate and the better the removal performance. In general, the pre-chlorination treatment with sodium hypochlorite (second treatment) is mainly for the purpose of oxidizing metals such as iron and manganese, not for removing soluble organic substances. However, according to the above findings, it is considered that a part of the soluble organic matter in the water to be treated is secondarily removed by the pre-chlorination treatment in which sodium hypochlorite is injected. By determining the injection rate of powdered activated carbon, it is considered that the injection amount of powdered activated carbon can be reduced from the conventional amount.

According to the findings described above, the processing rate RUV of soluble organic substances in the raw water is an injection rate I _ACP of powdered activated carbon, infusion rate and I _Cl of sodium hypochlorite, the injection rate I _PAC flocculant, It is considered that the pH (pH _R ) of the raw water is expressed as the following equation (7) with the variables.

This function g may be derived, for example, by a mathematical estimation method based on the RUV and the measured value of each parameter, or may be derived by a combination of the correlation between the RUV and each parameter. Then, by converting the obtained function g into a function for obtaining _IACP , the above equation (6) can be obtained.

Moreover, to calculate the value of the injection rate I _ACP calculated by equation (6), by providing a measure of the inlet flow Q _R of the raw water to the following equation (8), the injection quantity q _ACP of powdered activated carbon be able to.

The control device 80 of the first embodiment configured in this way has an injection rate of powdered activated carbon based on the injection rate of sodium hypochlorite and the injection rate of the flocculant, which are determined according to the water quality of the raw water. By determining the above, the injection amount of powdered activated carbon injected into the water to be treated for the purpose of removing soluble organic substances can be controlled more appropriately.

Specifically, based on the finding that the treatment rate of soluble organic substances correlates with the injection rate of sodium hypochlorite and coagulant, the injection rate of sodium hypochlorite and coagulant is first determined as the injection rate of raw water. It was decided according to the water quality, and the injection rate of powdered activated carbon was decided based on the injection rate of the determined sodium hypochlorite and coagulant injection rates. As a result, the injection amount of the powdered activated carbon can be suppressed by the amount of the soluble organic matter secondarily removed by the sodium hypochlorite and the flocculant.

In addition, based on the finding that the correlation between the DOC concentration of raw water and the absorbance of ultraviolet rays appears strongly with respect to ultraviolet rays having a wavelength of 260 nm, the ultraviolet absorbance of the wavelength should be used as an index for determining the amount of soluble organic matter in the raw water. I made it. As a result, the amount of soluble organic matter contained in the raw water can be estimated accurately, and the injection rate of the powdered activated carbon can be controlled more accurately according to the fluctuation of the water quality of the raw water.

The method for controlling the injection rate of powdered activated carbon described in the first embodiment is not limited to a water treatment system such as the water treatment system 100 in which solid-liquid separation is performed by a sedimentation pond 60 or a filtration pond 70, and hypochlorite. It can be applied to any water treatment system as long as it is a water treatment system in which sodium acid or a flocculant is injected after the injection step of powdered activated carbon. For example, the control method of the first embodiment can be applied to a water treatment system in which solid-liquid separation is performed by a membrane filtration method or a sand filtration method. In this case, the effect of suppressing the fouling of the membrane can be expected by removing the soluble organic substance, which is one of the causative substances of the fouling of the membrane, with an appropriate amount of powdered activated carbon.

The residual chlorine concentration of the filtered water may be used to determine the injection rate of sodium hypochlorite. In this way, it is possible to determine an appropriate injection rate of powdered activated carbon while maintaining the residual chlorine concentration of the filtered water at a predetermined target value.

In addition, the amount of chlorine consumed from the injection of sodium hypochlorite to the filtered water (hereinafter referred to as "chlorine consumption") can also be used to determine the injection rate of sodium hypochlorite. Good. In this way, it is possible to determine an appropriate injection rate of powdered activated carbon while maintaining the chlorine consumption at a predetermined target value.

Further, although the case where the filtered water is used as the treated water has been described here, the treated water does not necessarily have to be the filtered water. For example, in a water treatment system that does not have a filtration pond, the supernatant water of the sedimentation pond may be used as the treated water.

(Second Embodiment)
FIG. 10 is a diagram showing a configuration example of the water treatment system according to the second embodiment. The water treatment system 100a of the second embodiment is different from the water treatment system 100 of the first embodiment in that the control device 80a is provided in place of the control device 80 and the residual chlorine concentration meter 71 is further provided. Further, the control device 80a is different from the control device 80 in the first embodiment in that the powder activated carbon injection control unit 83a is provided in place of the powder activated carbon injection control unit 83. Since other configurations are the same as those of the first embodiment, the same reference numerals as those of FIG. 1 will be given to the same configurations as those of the first embodiment in FIG.

The residual chlorine concentration meter 71 measures the residual chlorine concentration RC _Cl of the filtered water. The residual chlorine concentration meter 71 is communicably connected to the control device 80a, and transmits measurement data to the control device 80a.

The powdered activated carbon injection control unit 83a includes the residual chlorine concentration RC _Cl of the filtered water measured by the residual chlorine concentration meter 71, the coagulant injection rate _IPAC determined by the coagulant injection control unit 82, and the ultraviolet absorbance of the raw water. The injection rate _IACP of the powdered activated carbon is determined based on UV ₀ , the residence time t of the water to be treated in the powdered activated carbon mixing pond 20, and the pH (pH _R ) of the raw water. In the first embodiment, the powdered activated carbon injection control unit 83a uses the residual chlorine concentration RC _Cl of the filtered water instead of the sodium hypochlorite injection rate I _Cl to determine the injection rate I _ACP of the powdered activated carbon. It is different from the powdered activated carbon injection control unit 83.

FIG. 11 is a diagram showing a specific example of the functional configuration of the powdered activated carbon injection control unit 83a. The powdered activated carbon injection control unit 83a is different from the powdered activated carbon injection control unit 83 in the first embodiment in that the powdered activated carbon injection rate calculation unit 833a is provided in place of the powdered activated carbon injection rate calculation unit 833. Since other configurations are the same as those of the first embodiment, the same reference numerals as those in FIG. 2 will be given to the same configurations as those of the first embodiment in FIG.

The powdered activated carbon injection rate calculation unit 833a is based on the residual chlorine concentration of the filtered water, the injection amount of the coagulant in the coagulant mixing pond 40, and the water quality of the raw water, and the powdered activated carbon according to the water quality target value of the treated water. It has a function to calculate the injection amount.

Specifically, the powdered activated carbon injection rate calculation unit 833a determines the measured value of the residual chlorine concentration RC _Cl of the filtered water, the value of the coagulant injection rate _IPAC , and the residence time of the water to be treated in the powdered activated carbon mixing pond 20. t and settings, the measured value of the pH _R is the pH of the raw water, the value of the target processing rate RUV, by providing the function f _'1, represented by the following formula (9), the injection of powdered activated carbon Calculate the rate I _ACP . Where the function f _'1, like the first embodiment, the residual chlorine concentration _{RC Cl} of filtered water, injection rate _{I PAC} flocculant, the set value of the dwell time t, and the raw water in the pH of the (pH _R) the measured values, 'calculated from (equation (10)), the function f' function defines the values and relationships of the target process rate RUV g information indicating ₁ is what is stored in advance powdered activated carbon injection rate calculating section 833a And.

FIG. 12 is a flowchart showing a flow of processing in which the control device 80a determines the injection rate of the powdered activated carbon in the powdered activated carbon mixing pond 20. In FIG. 12, the same processing as in the first embodiment is designated by the same reference numerals as those in FIG. 3, and the description thereof will be omitted. First, the control device 80a executes steps S101 to S105 in the same manner as in the first embodiment.

Subsequently, the control device 80a acquires the measured value of the residual chlorine concentration RC _Cl of the filtered water from the residual chlorine concentration meter 71 (S201). The control device 80a outputs the acquired measured value of the residual chlorine concentration to the powdered activated carbon injection rate calculation unit 833a.

Then calculated, powdered activated carbon injection rate calculating section 833a is, the value of the injection rate _{I PAC} of the calculated flocculant in step S102, the value of the measured raw water pH (pH _R) in step S103, in step S105 Based on the value of the target treatment rate RUV, the value of the residual chlorine concentration RC _CL of the filtered water measured in step S201, and the set value of the residence time t of the water to be treated in the powdered activated carbon mixing pond 20. The injection rate I _ACP of the powdered activated carbon in the powdered activated carbon mixing pond 20 is calculated (step S202).

The control device 80a of the second embodiment configured in this way determines the injection rate of the powdered activated carbon based on the injection rate of the coagulant determined according to the water quality of the raw water and the residual chlorine concentration of the filtered water. By determining, the injection amount of powdered activated carbon injected into the water to be treated for the purpose of removing soluble organic matter can be controlled more appropriately.

As described in the first embodiment, the treatment rate of the soluble organic matter correlates with the injection amount of sodium hypochlorite into the water to be treated. On the other hand, the injection amount of sodium hypochlorite is considered to correlate with the residual chlorine concentration of the filtered water. In this embodiment, the residual chlorine concentration of the filtered water is used as an index when determining the injection amount of the powdered activated carbon based on such a correlation. That is, this corresponds to correcting the injection rate of sodium hypochlorite determined by feedforward according to the raw water quality in the first embodiment by feedback based on the residual chlorine concentration. Thereby, as in the first embodiment, the injection rate of the powdered activated carbon can be determined in consideration of the effect of removing the soluble organic matter by the sodium hypochlorite and the flocculant.

The residual chlorine concentration of the filtered water used for determining the injection rate of powdered activated carbon may be used for determining the injection rate of sodium hypochlorite. In this way, it is possible to determine an appropriate injection rate of powdered activated carbon while maintaining the residual chlorine concentration of the filtered water at a predetermined target value.

Further, although the case where the filtered water is used as the treated water has been described here, the treated water does not necessarily have to be the filtered water. For example, in a water treatment system that does not have a filtration pond, the supernatant water of the sedimentation pond may be used as the treated water.

(Third Embodiment)
FIG. 13 is a diagram showing a configuration example of the water treatment system according to the third embodiment. The water treatment system 100b of the third embodiment is different from the water treatment system 100a of the second embodiment in that the control device 80b is provided in place of the control device 80. Further, the control device 80b is different from the control device 80a in the second embodiment in that the powder activated carbon injection control unit 83b is provided in place of the powder activated carbon injection control unit 83a and the chlorine consumption calculation unit 84 is further provided. Since other configurations are the same as those of the second embodiment, the same reference numerals as those in FIG. 10 will be given to the same configurations as those of the second embodiment in FIG. 13, and the description thereof will be omitted.

The chlorine consumption calculation unit 84 has the residual chlorine concentration RC _Cl of the filtered water measured by the residual chlorine concentration meter 71 and the injection rate I _{Cl of} sodium hypochlorite determined by the sodium hypochlorite injection control unit 81. And, the chlorine consumption DCL _Cl is calculated based on. The chlorine consumption calculation unit 84 outputs the calculated chlorine consumption to the powdered activated carbon injection control unit 83b. For example, the chlorine consumption calculation unit 84 determines the value of the injection rate I _Cl of sodium hypochlorite determined by the sodium hypochlorite injection control unit 81, and the residual filtered water measured by the residual chlorine concentration meter 71. The chlorine consumption DCL _Cl is calculated by giving the value of the chlorine concentration RC _Cl to the following formula (11).

The powdered activated carbon injection control unit 83b has a chlorine consumption DCL _Cl calculated by the chlorine consumption calculation unit 84, an injection rate _IPAC of the coagulant determined by the coagulant injection control unit 82, and an ultraviolet absorbance UV _{0 of} raw water. The injection rate I _ACP of the powdered activated carbon is determined based on the residence time t of the water to be treated in the powdered activated carbon mixing pond 20 and the pH (pH _R ) of the raw water. The powdered activated carbon injection control unit 83b and the powdered activated carbon injection control unit 83a in the second embodiment use the chlorine consumption DCL _Cl instead of the residual chlorine concentration RC _Cl of the filtered water to determine the injection rate of the powdered activated carbon. different.

FIG. 14 is a diagram showing a specific example of the functional configuration of the powdered activated carbon injection control unit according to the third embodiment. The powdered activated carbon injection control unit 83b is different from the powdered activated carbon injection control unit 83a in the second embodiment in that the powdered activated carbon injection rate calculation unit 833b is provided in place of the powdered activated carbon injection rate calculation unit 833a. Since other configurations are the same as those of the second embodiment, the same reference numerals as those of FIG. 11 will be given to the same configurations as those of the second embodiment in FIG. 14, and the description thereof will be omitted.

The powdered activated carbon injection rate calculation unit 833b determines the injection amount of powdered activated carbon according to the water quality target value of the treated water based on the chlorine consumption amount, the injection amount of the coagulant in the coagulant mixing pond 40, and the water quality of the raw water. It has a function to calculate.

Specifically, powdered activated carbon injection rate calculating section 833b compares the value of the chlorine consumption DCL _Cl calculated by chlorine consumption calculation unit 84, the value of the injection rate I _PAC flocculant, in powdered activated mixing basin 20 The set value of the residence time t of the water to be treated, the measured value of the pH (pH _R ) of the raw water, and the value of the target treatment rate RUV are given to the function f " ₁ represented by the following formula (12). The injection rate I _ACP of the powdered activated carbon is calculated by the above method. Here, the function f " ₁ is a set value of the chlorine consumption DCL _Cl , the coagulant injection rate I _PAC , and the residence time t, as in the second embodiment. , And the function g "(formula (13)) that defines the relationship between the measured value of the pH (pH _R ) of the raw water and the value of the target treatment rate RUV, and the information indicating the function f" ₁ is obtained in advance from the powdered activated carbon. It is assumed that it is stored in the injection rate calculation unit 833b.

FIG. 15 is a flowchart showing a flow of processing in which the control device 80b determines the injection rate of the powdered activated carbon in the powdered activated carbon mixing pond 20. In FIG. 15, the same processing as in the second embodiment is designated by the same reference numerals as those in FIG. 12, and the description thereof will be omitted. First, the control device 80b executes steps S101 to S201 in the same manner as in the second embodiment. The control device 80b outputs the measured value of the residual chlorine concentration acquired in step S201 to the chlorine consumption calculation unit 84.

Subsequently, the chlorine consumption calculation unit 84 determines the value of the sodium hypochlorite injection rate I _Cl calculated in step S101 and the value of the residual chlorine concentration RC _Cl of the filtered water measured in step S201. Based on this, the value of chlorine consumption DCL _Cl is calculated (step S301). The chlorine consumption calculation unit 84 outputs the calculated chlorine consumption DCL _Cl value to the powdered activated carbon injection rate calculation unit 833b.

Then calculated, powdered activated carbon injection rate calculating section 833b compares the value of the injection rate _{I PAC} of the calculated flocculant in step S102, the value of the measured raw water pH (pH _R) in step S103, in step S105 Powdered activated carbon injection based on the determined target treatment rate RUV value, the chlorine consumption DCL _Cl value calculated in step S301, and the set value of the residence time t of the water to be treated in the powdered activated carbon mixing pond 20. The injection rate _IACP of the powdered activated carbon to be injected into the device 21 is calculated (step S302).

The control device 80b of the third embodiment configured in this way determines the injection rate of the powdered activated carbon based on the injection rate of the flocculant and the chlorine consumption determined according to the water quality of the raw water. Thereby, the injection amount of the powdered activated carbon injected into the water to be treated for the purpose of removing the soluble organic matter can be controlled more appropriately.

As described in the first embodiment, the treatment rate of the soluble organic matter correlates with the injection amount of sodium hypochlorite into the water to be treated. On the other hand, the injection amount of sodium hypochlorite is considered to correlate with the residual chlorine concentration of the filtered water. In this embodiment, chlorine consumption calculated based on the injection amount of sodium hypochlorite and the residual chlorine concentration of the filtered water is used as an index for determining the injection amount of powdered activated carbon based on such a correlation. The amount is used. Thereby, as in the second embodiment, the injection rate of the powdered activated carbon can be determined in consideration of the effect of removing the soluble organic matter by the sodium hypochlorite and the flocculant.

The residual chlorine concentration of the filtered water used for determining the injection rate of powdered activated carbon may be used for determining the injection rate of sodium hypochlorite. In this way, it is possible to determine an appropriate injection rate of powdered activated carbon while maintaining the residual chlorine concentration of the filtered water at a predetermined target value.

Further, although the case where the filtered water is used as the treated water has been described here, the treated water does not necessarily have to be the filtered water. For example, in a water treatment system that does not have a filtration pond, the supernatant water of the sedimentation pond may be used as the treated water.

The function of the control device in the above-described embodiment may be realized by a computer. In that case, the program for realizing this function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed. The term "computer system" as used herein includes hardware such as an OS and peripheral devices. Further, the "computer-readable recording medium" refers to a portable medium such as a flexible disk, a magneto-optical disk, a ROM, or a CD-ROM, or a storage device such as a hard disk built in a computer system. Further, a "computer-readable recording medium" is a communication line for transmitting a program via a network such as the Internet or a communication line such as a telephone line, and dynamically holds the program for a short period of time. It may also include a program that holds a program for a certain period of time, such as a volatile memory inside a computer system that serves as a server or a client in that case. Further, the above-mentioned program may be a program for realizing a part of the above-mentioned functions, and may be a program for realizing the above-mentioned functions in combination with a program already recorded in the computer system.

According to at least one embodiment described above, the powdered activated carbon in the powdered activated carbon mixed pond is based on the injection rate of sodium hypochlorite in the prechlorinated pond and the coagulant injection rate in the coagulant mixed pond. By having a powdered activated carbon injection control unit that determines the injection rate, or a powdered activated carbon injection control unit that determines the powdered activated carbon injection rate in the powdered activated carbon mixed pond based on the coagulant injection rate in the coagulant mixed pond. It is possible to provide a control device, a control method and a computer program capable of more appropriately controlling the injection amount of powdered activated carbon injected into the water to be treated for the purpose of removing soluble organic substances.

Although some embodiments of the present invention have been described, these embodiments are presented as examples 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 changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention as well as the invention described in the claims and the equivalent scope thereof.

100, 100a, 100b ... Water treatment system of the embodiment, 10 ... Water well, 11 ... Water quality measuring instrument, 12 ... UV (Ultra Violet) measuring instrument, 13 ... Flow meter, 20 ... Powdered activated carbon mixture pond, 21 ... Powdered activated carbon Injection device, 30 ... pre-chlorine mixing pond, 31 ... sodium hypochlorite injection device, 40 ... coagulant mixing pond, 41 ... coagulant injection device, 42 ... pH measuring device, 50 ... floc forming pond, 51, 51- 1-51-3 ... Stirrer, 60 ... Precipitation pond, 70 ... Filtration pond, 71 ... Residual chlorine concentration meter, 80, 80a, 80b ... Control device, 81 ... Sodium hypochlorite injection control unit, 82 ... Aggregator injection Control unit, 83, 83a, 83b ... Powdered activated carbon injection control unit, 831 ... Target absorbance calculation unit, 832 ... Target processing rate calculation unit, 833, 833a, 833b ... Powdered activated carbon injection rate calculation unit, 84 ... Chlorine consumption calculation unit

Claims (15)

In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. A control device for a water treatment system that sequentially performs a second treatment of oxidizing and a third treatment of coagulating and sedimenting suspended substances contained in the water to be treated with a coagulant in a coagulant mixing pond.
A sodium hypochlorite injection control unit that determines the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water that is the water to be treated before the first treatment.
A coagulant injection control unit that determines the coagulant injection rate in the third treatment based on the quality of the raw water,
Based on the ultraviolet absorbance of the raw water, the injection rate of sodium hypochlorite determined by the sodium hypochlorite injection control unit, and the injection rate of the coagulant determined by the coagulant injection control unit. A powdered activated carbon injection control unit that determines the injection rate of powdered activated carbon in the first treatment,
A control device comprising. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. A control device for a water treatment system that sequentially performs a second treatment of oxidizing and a third treatment of coagulating and sedimenting suspended substances contained in the water to be treated with a coagulant in a coagulant mixing pond.
A sodium hypochlorite injection control unit that determines the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water that is the water to be treated before the first treatment.
A coagulant injection control unit that determines the coagulant injection rate in the third treatment based on the quality of the raw water,
Powdered activated carbon that determines the injection rate of powdered activated carbon in the first treatment based on the ultraviolet absorbance of the raw water, the residual chlorine concentration of the treated water, and the injection rate of the coagulant determined by the coagulant injection control unit. Injection control unit and
A control device comprising. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. A control device for a water treatment system that sequentially performs a second treatment of oxidizing and a third treatment of coagulating and sedimenting suspended substances contained in the water to be treated with a coagulant in a coagulant mixing pond.
A sodium hypochlorite injection control unit that determines the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water that is the water to be treated before the first treatment.
A coagulant injection control unit that determines the coagulant injection rate in the third treatment based on the quality of the raw water,
From the injection of sodium hypochlorite to the treated water based on the residual chlorine concentration of the treated water and the injection rate of sodium hypochlorite determined by the sodium hypochlorite injection control unit. Chlorine consumption calculation unit that calculates the consumed chlorine consumption,
Based on the ultraviolet absorbance of the raw water, the chlorine consumption calculated by the chlorine consumption calculation unit, and the injection rate of the coagulant determined by the coagulant injection control unit, the powdered activated carbon in the first treatment Powdered activated carbon injection control unit that determines the injection rate,
A control device comprising. The powdered activated carbon injection control unit
A target absorbance determining unit that determines the target absorbance, which is the target value of the ultraviolet absorbance of the water to be treated, corresponding to the water quality target value of the treated water.
A target processing rate calculation unit that calculates a target processing rate represented by the ratio of the target absorbance to the ultraviolet absorbance of the raw water,
The target treatment rate, the injection rate of sodium hypochlorite determined by the sodium hypochlorite injection control unit, the injection rate of the coagulant determined by the coagulant injection control unit, and the powdered activated carbon mixture. A powdered activated carbon injection rate calculation unit that determines the injection rate of powdered activated carbon in the first treatment based on the residence time of the water to be treated in the pond and the pH of the raw water.
To prepare
The control device according to claim 1. The powdered activated carbon injection control unit
A target absorbance determining unit that determines the target absorbance, which is the target value of the ultraviolet absorbance of the water to be treated, corresponding to the water quality target value of the treated water.
A target processing rate calculation unit that calculates a target processing rate represented by the ratio of the target absorbance to the ultraviolet absorbance of the raw water,
The target treatment rate, the residual chlorine concentration of the treated water, the injection rate of the coagulant determined by the coagulant injection control unit, the residence time of the water to be treated in the powdered activated carbon mixing pond, and the pH of the raw water. Based on the above, the powdered activated carbon injection rate calculation unit that determines the powdered activated carbon injection rate in the first treatment, and
To prepare
The control device according to claim 2. The powdered activated carbon injection control unit
A target absorbance determining unit that determines the target absorbance, which is the target value of the ultraviolet absorbance of the water to be treated, corresponding to the water quality target value of the treated water.
A target processing rate calculation unit that calculates a target processing rate represented by the ratio of the target absorbance to the ultraviolet absorbance of the raw water,
The target treatment rate, the chlorine consumption, the injection rate of the coagulant determined by the coagulant injection control unit, the residence time of the water to be treated in the powdered activated carbon mixing pond, and the pH of the raw water. Based on the powdered activated carbon injection rate calculation unit that determines the powdered activated carbon injection rate in the first treatment,
To prepare
The control device according to claim 3. The water quality target value of the treated water is a target value of the soluble organic carbon concentration in the treated water.
The control device according to any one of claims 4 to 6. The coagulant injection control unit injects the coagulant in the third treatment based on at least one of turbidity, alkalinity or water temperature as the water quality of the raw water and the pH of the miscible water in the coagulant mixing pond. Determine the rate,
The control device according to any one of claims 1 to 7. The sodium hypochlorite injection control unit determines the injection rate of sodium hypochlorite in the second treatment based on at least one of the required chlorine amount or the ammonia concentration as the water quality of the raw water.
The control device according to any one of claims 1 to 8. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. It is a control method of a water treatment system that sequentially performs a second treatment of oxidizing and a third treatment of coagulating and sedimenting a suspended substance contained in the water to be treated with a coagulant in a coagulant mixing pond.
The first step of determining the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water which is the water to be treated before the first treatment, and
The second step of determining the injection rate of the flocculant in the third treatment based on the water quality of the raw water, and
In the first treatment, based on the ultraviolet absorbance of the raw water, the injection rate of sodium hypochlorite determined in the first step, and the injection rate of the flocculant determined in the second step. The third step of determining the injection rate of powdered activated carbon,
Control method having. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are separated by sodium hypochlorite. A control device for a water treatment system that sequentially performs a second treatment for oxidation and a third treatment for aggregating and sedimenting suspended substances contained in the water to be treated with a coagulant in a coagulant mixing pond.
The first step of determining the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water which is the water to be treated before the first treatment, and
The second step of determining the injection rate of the flocculant in the third treatment based on the water quality of the raw water, and
A third method for determining the injection rate of powdered activated carbon in the first treatment based on the ultraviolet absorbance of the raw water, the residual chlorine concentration of the treated water, and the injection rate of the flocculant determined in the second step. Steps and
Control method having. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. It is a control method of a water treatment system that sequentially performs a second treatment of oxidizing and a third treatment of coagulating and sedimenting a suspended substance contained in the water to be treated with a coagulant in a coagulant mixing pond.
The first step of determining the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water which is the water to be treated before the first treatment, and
The second step of determining the injection rate of the flocculant in the third treatment based on the water quality of the raw water, and
Chlorine consumed from the injection of sodium hypochlorite to the filtered water based on the residual chlorine concentration of the treated water and the injection rate of sodium hypochlorite determined in the first step. The third step in calculating consumption and
The injection rate of powdered activated carbon in the first treatment is based on the ultraviolet absorbance of the raw water, the chlorine consumption calculated in the third step, and the injection rate of the flocculant determined in the second step. The fourth step to determine and
Control method having. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. A computer that functions as a control device for a water treatment system that sequentially performs a second treatment for oxidation and a third treatment for aggregating and sedimenting suspended substances contained in the water to be treated with a coagulant in a coagulant mixing pond.
The first step of determining the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water which is the water to be treated before the first treatment, and
The second step of determining the injection rate of the flocculant in the third treatment based on the water quality of the raw water, and
In the first treatment, based on the ultraviolet absorbance of the raw water, the injection rate of sodium hypochlorite determined in the first step, and the injection rate of the flocculant determined in the second step. The third step of determining the injection rate of powdered activated carbon,
A computer program to run. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. A computer that functions as a control device for a water treatment system that sequentially performs a second treatment for oxidation and a third treatment for aggregating and sedimenting suspended substances contained in the water to be treated with a coagulant in a coagulant mixing pond.
The first step of determining the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water which is the water to be treated before the first treatment, and
The second step of determining the injection rate of the flocculant in the third treatment based on the water quality of the raw water, and
A third method for determining the injection rate of powdered activated carbon in the first treatment based on the ultraviolet absorbance of the raw water, the residual chlorine concentration of the treated water, and the injection rate of the flocculant determined in the second step. Steps and
A computer program to run. In the powdered activated carbon mixing pond, the first treatment of adsorbing the soluble organic matter contained in the water to be treated to the powdered activated carbon, and in the prechlorination pond, the metals and ammonia nitrogen contained in the water to be treated are treated with sodium hypochlorite. A computer that functions as a control device for a water treatment system that sequentially performs a second treatment for oxidation and a third treatment for aggregating and sedimenting suspended substances contained in the water to be treated with a coagulant in a coagulant mixing pond.
The first step of determining the injection rate of sodium hypochlorite in the second treatment based on the quality of the raw water which is the water to be treated before the first treatment, and
The second step of determining the injection rate of the flocculant in the third treatment based on the water quality of the raw water, and
Chlorine consumed from the injection of sodium hypochlorite to the filtered water based on the residual chlorine concentration of the treated water and the injection rate of sodium hypochlorite determined in the first step. The third step in calculating consumption and
The injection rate of powdered activated carbon in the first treatment is based on the ultraviolet absorbance of the raw water, the chlorine consumption calculated in the third step, and the injection rate of the flocculant determined in the second step. The fourth step to determine and
A computer program to run.

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