JP2022187271A - Powdery activated carbon injection control system, powdery activated carbon injection control method, powdery activated carbon injection control device, and program - Google Patents

Abstract

To optimize an injection rate of powdery activated carbon.SOLUTION: A powdery activated carbon injection control system comprises: algae detection/determination means for detecting algae contained in raw water to determine species of the algae; odor substance estimation means for estimating a kind of an odor substance emitted from the algae, from the species of the algae determined by the algae detection/determination means; odor substance concentration measurement means for measuring a concentration of an odor substance contained in the raw water or in treated water after powdery activated carbon injection treatment, targeting the kind of the odor substance estimated by the odor substance estimation means; and powdery activated carbon injection control means for calculating an injection rate of odor substance corresponding powdery activated carbon for making the concentration of the odor substance contained in water to be treated in a raw water receiving well equal to a target concentration by using at least the concentration of the odor substance measured by the odor substance concentration measurement means, and controlling an injection amount of powdery activated carbon to be injected into the water to be treated in the raw water receiving well or into water to be treated in a coagulant mixing pond on the basis of the injection rate of the odor substance corresponding powdery activated carbon.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to a powdered activated carbon injection control system, a powdered activated carbon injection control method, a powdered activated carbon injection control device, and a program.

It is known that algae (hereinafter also referred to as phytoplankton) proliferate abnormally in dams, lakes, reservoirs, etc., which serve as water sources for water supply, and impede water purification treatment due to progress of eutrophication.
Some of these algae produce odorous substances such as musty odors, which are the cause of the offensive odors and tastes in tap water. .

In addition to odorous substances, raw water in water purification treatment contains soluble organic substances such as humic substances, turbid substances such as fine particles, and metal ions such as iron and manganese.

On the other hand, at water purification plants, chemicals such as sodium hypochlorite are injected for the purpose of removing metal ions such as iron and manganese and for disinfection. Substances and drugs chemically react to produce disinfection by-products such as carcinogenic trihalomethanes and haloacetic acids.

Many water purification plants inject powdered activated carbon to remove odorous substances and soluble organic substances contained in raw water, and coagulants to remove turbidity. In a water treatment system using this powdered activated carbon, it is necessary to adjust the injection rate of the powdered activated carbon according to the type and concentration of odorous substances and the composition and concentration of soluble organic substances in the water to be treated.

A jar test (hereinafter also referred to as a beaker test) is often used as a method for determining the injection rate of powdered activated carbon. In the jar test, the water to be treated is sampled into multiple beakers, different amounts of powdered activated carbon are injected into each of the multiple samples of water to be treated, and the removal rate of odorants and soluble organic substances is evaluated. Then, the minimum powdered activated carbon injection rate required to reduce the post-treatment odor concentration and soluble organic matter to below the target concentration is obtained.

However, in the method of determining the injection rate of powdered activated carbon by a jar test, it is very difficult to inject the powdered activated carbon in accordance with changes in the water quality of the water to be treated, and there is a risk that the injection rate will be excessive or insufficient. In addition, since the jar test requires time to determine the optimum injection rate of powdered activated carbon, the quality of the water to be treated may have changed when the optimum injection rate of powdered activated carbon is obtained.

In particular, it is known that the adsorption of odorous substances by powdered activated carbon is affected by the type of odorant, the molecular structure and concentration of coexisting soluble organic substances, and the adsorption is inhibited.

Moreover, when determining the injection rate of the powdered activated carbon to be actually charged, the injection rate is determined on the safer side than the injection rate obtained by the jar test, resulting in excessive injection.

Powdered activated carbon has a very high unit price compared to other chemicals such as flocculants, sulfuric acid, and sodium hypochlorite. Therefore, excessive injection of powdered activated carbon may lead to a sharp rise in chemical costs. A technique for controlling the injection rate is desired.

JP 2005-288309 A JP 2014-124593 A JP 2018-134039 A

The problem to be solved by the present invention is to provide a powdered activated carbon injection control system, a powdered activated carbon injection control method, a powdered activated carbon injection control device, and a program, which are capable of optimizing the powdered activated carbon injection rate. .

The powdered activated carbon injection control system of the embodiment includes algae detection determination means for detecting algae contained in raw water and determining the type of algae, and the type of algae determined by the algae detection determination means. Odor substance estimating means for estimating the type of odor substance, and measuring the concentration of the odor substance contained in the raw water or the treated water after the powdered activated carbon injection treatment with respect to the type of the odor substance estimated by the odor substance estimation means. and an odorant concentration measuring means for adjusting the concentration of the odorant contained in the treated water of the receiving well to a target concentration using at least the concentration of the odorant measured by the odorant concentration measuring means. Powder activated carbon injection for calculating the powdered activated carbon injection rate corresponding to the odorant, and controlling the amount of powdered activated carbon to be injected into the water to be treated in the receiving well or the water to be treated in the coagulant mixing pond based on the powdered activated carbon injection rate corresponding to the odor substance. and a control means.

The figure which shows an example of a structure of the water treatment system which concerns on 1st Embodiment. 1 is a diagram showing an example of the configuration of an algae detection/determination device 11; FIG. 4 is a diagram showing an example of odorant reference information stored as an odorant reference database in the odorant estimation device 12; FIG. FIG. 2 is a diagram showing an example of the configuration of an odorant concentration measuring device 13; FIG. 13 is a graph showing the relationship between the output change dV/dt of the odor sensor 13d and the concentration of the odorant "dimethylisoborneol" and an example of a conversion formula. FIG. 4 is a graph showing the relationship between the output change dV/dt of the odor sensor 13d and the concentration of the odorous substance “geosmin” and an example of a conversion formula. FIG. 4 is a graph showing the relationship between the output change dV/dt of the odor sensor 13d and the concentration of the odorous substance “2,4-decadienal” and an example of a conversion formula. 4 is a flow chart showing an example of operations related to the powdered activated carbon injection control system of the first embodiment; 4 is a flowchart showing an example of detailed operation of setting processing and arithmetic processing related to the powdered activated carbon injection control system of the embodiment; Graph showing test results by the inventors when dimethylisoborneol or geosmin was added to raw water of a certain water purification plant and the same powdered activated carbon injection treatment was performed. 5 is a graph showing test results when dimethylisoborneol was added to pure water, and humic acid and fulvic acid were added at different mixing ratios, and powdered activated carbon was injected. 5 is a graph showing the test results when geosmin was added to pure water, and humic acid and fulvic acid were added at different mixing ratios, and powdered activated carbon was injected. After adding a flocculant to the water to be treated, which has been adjusted to the raw water soluble organic carbon concentration _DOCR = 2.5 (mg/L) and the mixed water pH _F = 6.5, rotate at 150 (rpm) for 10 minutes. The graph which shows the test result at the time of rapid-stirring processing and slow-stirring processing for 60 minutes at rotation speed 80 (rpm). After rapidly stirring the powdered activated carbon treatment at 150 (rpm) for 60 minutes, the hydrogen ion concentration index (pH) is adjusted to a predetermined value, a flocculant is added, and the mixture is rapidly stirred at 150 (rpm) for 10 minutes and rotated. The graph which shows the test result at the time of slow-stirring processing for 60 minutes at several 80 (rpm). The figure which shows the relationship between the specific absorbance SUVA and the coefficient f. The figure which shows an example of a structure of the odorant concentration measuring apparatus 13 in 2nd Embodiment. The figure which shows an example of a structure of the water treatment system which concerns on 3rd Embodiment. 11 is a flow chart showing an example of operations related to the powdered activated carbon injection control system of the third embodiment; 4 is a flowchart showing an example of detailed operation of setting processing and arithmetic processing related to the powdered activated carbon injection control system of the embodiment;

Embodiments will be described below with reference to the drawings.

<First Embodiment>
First, the first embodiment will be described.

[System configuration]
Drawing 1 is a figure showing an example of composition of a water treatment system concerning a 1st embodiment.

Here, an example in which the water treatment system according to the present embodiment is applied to a rapid sand filtration type water treatment facility is shown. However, the water treatment system of the present embodiment is not limited to the rapid sand filtration type water treatment facility, and can be applied to other types of water treatment facility. For example, it can be applied to membrane filtration type water treatment equipment and sand filtration type water treatment equipment.

In the water treatment facility 1 shown in FIG. 1, "adsorption treatment" and "coagulation treatment" are performed. The adsorption treatment is a treatment for adsorbing and removing odorous substances and soluble organic substances contained in landing water with powdered activated carbon. The flocculation process is a process of flocculating and sedimenting turbidity contained in landing water using a flocculating agent.

The water treatment facility 1 includes a receiving well 20, a powdered activated carbon injection device 21, a coagulant mixing basin 30, a coagulant injection device 31, a coagulation/sedimentation basin 40, and a filtration basin and a clean water basin (not shown).

The receiving well 20 receives the raw water (water to be treated) sent through the pipe 2 and stabilizes it as landing. This receiving well 20 is provided with a powder activated carbon injector 21 for the above-described adsorption treatment. The powdered activated carbon injection device 21 performs a powdered activated carbon injection process of injecting powdered activated carbon into the water to be treated. The powdered activated carbon injected into the water to be treated adsorbs odorous substances and soluble organic substances contained in the raw water. The water to be treated that has been subjected to the adsorption treatment in the receiving well 20 is guided to the coagulant mixing pond 30 through the pipe 3 .

The coagulant mixing pond 30 receives the water to be treated sent through the pipe 3 . The flocculant mixing pool 30 is provided with a flocculant injection device 31 for the flocculation treatment described above. The coagulant injection device 31 performs a coagulant injection process of injecting a coagulant into the water to be treated. The flocculant injected into the water to be treated aggregates suspended matter (turbidity) such as clay, bacteria and algae contained in the raw water and the powdered activated carbon injected in the receiving well 20 to form fine flocs. . As the flocculant, it is preferable to use an aluminum-based flocculant and an iron-based flocculant. Examples of aluminum-based flocculants include aluminum sulfate (aluminum sulfate) and polyaluminum chloride (PACl). Examples of iron-based flocculants include iron chloride, iron sulfate, and iron polysilica.

The coagulant mixing pond 30 is also provided with an oxidant injection device 32 for adjusting the hydrogen ion concentration index (pH value) of the water to be treated. The oxidant injector 32 injects an oxidant such as sulfuric acid into the water to be treated. The oxidizing agent injected into the water to be treated changes the hydrogen ion concentration index (pH value) of the water to be treated.

In addition, the coagulant mixing pond 30 is provided with an agitator 30a for agitating the water to be treated. This stirrer 30a is configured using, for example, a flash mixer. The water to be treated into which the flocculant and the oxidizing agent have been injected in the flocculant mixing tank 30 is stirred by the agitator 30 a to become mixed water, which is led through the pipe 4 to the flocculation/sedimentation tank 40 .

The water treatment system according to this embodiment includes a treated water quality target setting device 100 , a powdered activated carbon injection control device 200 and a coagulant injection control device 300 .

The treated water quality target setting device 100 sets target values for various physical quantities indicating the quality of the water to be treated. The powdered activated carbon injection control device 200 controls the powdered activated carbon injection device 21 that injects powdered activated carbon into the water to be treated in the receiving well 20 . The coagulant injection control device 300 controls the coagulant injection device 31 that injects the coagulant into the water to be treated in the coagulant mixing pond 30 and the oxidant injection device 32 that injects the oxidant.

The treated water quality target setting device 100, the powdered activated carbon injection control device 200, and the coagulant injection control device 300 may be collectively realized as one computer, or may be realized as individual computers. good. Further, the powdered activated carbon injection control device 200 and the flocculant injection control device 300 may be combined and realized as one computer. The functions of the treated water quality target setting device 100, the powdered activated carbon injection control device 200, and the coagulant injection control device 300 are realized as programs executed by a processor such as a central processing unit provided in a computer. good too. Details of the treated water quality target setting device 100, the powdered activated carbon injection control device 200, and the coagulant injection control device 300 will be described later.

The pipe 2 includes a water quality meter set 10, an algae detection determination device (algae detection determination means) 11, an odorant estimation device (odorant estimation means) 12, an odorant concentration measurement device (odorant concentration measurement means) 13, a solubility An organic substance indicator instrument set (soluble organic substance indicator measuring means) 14 and a flow meter 15 are provided. At least these instruments and the powdered activated carbon injection control device 200 constitute a powdered activated carbon injection control system that controls injection of powdered activated carbon.

The water quality meter set 10 measures the water quality of raw water. This water quality instrument set 10 includes a turbidity meter 10a for measuring the turbidity of the raw water, an alkalinity meter 10b for measuring the alkalinity of the raw water, a water thermometer 10c for measuring the temperature of the raw water, and a hydrogen ion concentration (pH value) of the raw water. ) is included. Data measured by these instruments are supplied to the flocculant injection controller 300 .

The algae detection and determination device 11 detects algae contained in raw water, determines the type of algae (at least one of attributes and species), counts each type of algae, and generates algae information indicating the results. be. For example, the algae detection and determination device 11 collects part of the raw water from the pipe 2 into which the raw water flows, detects the target algae by observing the inside of the raw water with a special camera, and determines the type (attribute and species) judge. The algae information data generated by the algae detection and determination device 11 is supplied to the odorant estimation device 12 . This algae information data may also be supplied to the powdered activated carbon injection control device 200 .

Based on the algae information sent from the algae detection and determination device 11, the odorant estimation device 12 estimates the type of odorant emitted by the algae based on the type of algae determined by the algae detection and determination device 11. Data indicating the type of algae estimated by the odorant estimation device 12 is supplied to the odorant concentration measurement device 13 . The data indicating the type of algae may also be supplied to the powdered activated carbon injection control device 200 .

The odorant concentration measuring device 13 measures the concentration of the odorant contained in the raw water for the type of the odorant estimated by the odorant estimation device 12 . Concentration data measured by the odorant concentration measuring device 13 is supplied to the powdered activated carbon injection control device 200 .

The soluble organic matter indicator instrument set 14 measures at least one of ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration (DOC) of raw water as a soluble organic matter index value. This soluble organic substance indicator instrument set 14 includes an ultraviolet absorbance meter 14a for measuring the ultraviolet absorbance of the raw water, a fluorescence intensity meter 14b for measuring the fluorescence intensity of the raw water, and a soluble organic substance indicator for measuring the soluble organic carbon concentration of the raw water. Includes an airframe carbon concentration meter (DOC meter) 14c. Data on the soluble organic matter index value measured by each instrument is supplied to the powdered activated carbon injection control device 200 .

The flow meter 15 measures the flow rate of raw water. Flow rate data measured by the flow meter 15 is supplied to the powdered activated carbon injection control device 200 .

In addition, the coagulant mixing pond 30 is provided with a hydrogen ion concentration index measuring device (pH measuring device) 16 . This hydrogen ion concentration index measuring device 16 measures the hydrogen ion concentration index (pH value) of the mixed water in the coagulant mixing pond 30 . The hydrogen ion concentration index data measured by the hydrogen ion concentration index measuring device 16 is supplied to the coagulant injection control device 300 .

[Configuration of algae detection and determination device 11]
FIG. 2 is a diagram showing an example of the configuration of the algae detection/determination device 11. As shown in FIG.

As shown in FIG. 2, the algae detection/judgment device 11 detects algae contained in raw water based on an observation cell 11d composed of, for example, a flow cell 11a, a lighting 11b, and a camera 11c, and an image taken by the camera 11c. , a computer 11f containing image analysis software for judging the type (attribute and species) of detected algae and counting for each type of algae, an algae reference database, etc., and a display device for displaying the results processed by the computer 11f. 11g. The algae information generated by the algae detection/determining device 11 is supplied to the odorant estimation device 12 .

Note that the configuration of the algae detection/determination device 11 is not limited to the example in FIG. A different configuration may be adopted as long as it can realize an equivalent function.

[Odor substance reference information possessed by odor substance estimation device 12]
FIG. 3 is a diagram showing an example of odorant reference information stored in the odorant estimation device 12 as an odorant reference database.

The odorant reference information is information indicating the relationship between various types of algae and odorants produced from these algae. In the example of odorant reference information shown in FIG. 3, "Anabaena", "Oscillatria", "Phormidium", and [Urogrena] are described as algae, and "Geosmin" and "2-MIB" are described as corresponding odorants, respectively. (dimethylisoborneol)”, “2-MIB (dimethylisoborneol)”, and “2,4-decadienal”.

Based on the information, the odorant estimation device 12 estimates the type of odorant that is most likely contained in the raw water from the algae species indicated in the algae information supplied from the algae detection and determination device 11 . Odor substance information indicating the type of odor substance estimated by the odor substance estimation device 12 is supplied to the odor substance concentration measurement device 13 and the powdered activated carbon injection control device 200 .

Note that the odorant reference information is not limited to the example shown in FIG. Other information may be adopted as long as it can realize an equivalent function.

[Configuration of odorant concentration measuring device 13]
FIG. 4 is a diagram showing an example of the configuration of the odorant concentration measuring device 13. As shown in FIG.

The odorant concentration measuring device 13 shown in FIG. 4 includes an odorant extraction tank 13a, a dehumidifier 13b, an odor sensor cell 13c, an odor sensor head (hereinafter referred to as "odor sensor") 13d, and an odorant concentration calculator 13f. .

An overflow tray 13a-1 and a raw water introduction pipe 13a-2 are provided inside the odorant extraction tank 13a. A heater 13a-3 is built in the raw water inlet pipe 13a-2, and heats the raw water to a predetermined temperature to evaporate the odorous substance in the raw water together with the steam. The evaporated water vapor and odorous substances are sent to the dehumidifier 13b together with the air taken in by the air supply fan 13a-4 attached to the odorant extraction tank 13a, where the water vapor is separated to produce dry air containing odorous substances. is sent to the odor sensor cell 13c. An odor sensor 13d that reacts to an odorant is attached to the odor sensor cell 13c, and an output corresponding to the concentration of the odorant is sent to the odorant concentration calculator 13f.

The odorant concentration calculation unit 13f calculates the relationship between the output change dV/dt of the odor sensor 13d (temporal change (inclination) of the sensor output V) and the odorant concentration for each assumed odorant. From among various conversion formulas, a conversion formula corresponding to the type of odorant indicated in the odorant information supplied from the odorant estimation device 12 is selected, and based on this conversion formula, the odor The concentration of the odorant is obtained from the output change dV/dt of the sensor 13d. Concentration information indicating this concentration is supplied to the powdered activated carbon injection control device 200 . Although the output change dV/dt of the odor sensor 13d is confirmed, if the type of the corresponding odorant cannot be obtained from the odorant information supplied from the odorant estimation device 12, dimethylisoborneol is used as the virtual odorant. , the density may be obtained from the corresponding conversion formula.

Here, the relationship between the output change of the odor sensor 13d and the concentration of various odorants will be described with reference to FIGS. 5A, 5B, and 5C.

[Relationship between Output Change of Odor Sensor 13d and Concentration of Various Odor Substances]
FIG. 5A is a diagram showing an example of a graph and a conversion formula showing the relationship between the output change dV/dt of the odor sensor 13d and the concentration of the odorant "dimethylisoborneol". FIG. 5B is a diagram showing an example of a graph and a conversion formula showing the relationship between the output change dV/dt of the odor sensor 13d and the concentration of the odorant "geosmin". FIG. 5C is a graph showing the relationship between the output change dV/dt of the odor sensor 13d and the concentration of the odorant "2,4-decadienal" and an example of a conversion formula.

The output of the odor sensor is output as voltage (mV) or frequency (Hz). As the odorant adheres to the odor sensor 13d, the output V increases with the lapse of time (t). At this time, the magnitude of change dV (inclination) of the output per unit time dt (sec) is proportional to the odorant concentration. In addition, since the proportionality constant differs depending on the type of odorant, the proportionality coefficient k corresponding to each odorant is set in advance, and the type of odorant indicated in the odorant information supplied from the odorant estimating device 12 is used. By selecting a corresponding conversion formula, the odorant concentration of raw water can be measured.

Examples of conversion formulas corresponding to dimethylisoborneol, geosmin, and 2,4-decadienal are shown below.

C2 _-MIB = k2 _-MIB x dV/dt + v (1)

C _Geosmin = k _Geosmin x dV/dt + v (2)

CD= _kD × _dV /dt+v (3)

Here, C: odorant concentration (ng/L), subscript 2-MIB: dimethylisoborneol, subscript Geosmin: geosmin, subscript D: 2,4-decadienal, k: proportional coefficient, dV: Output change (mV or Hz), dt: time change (sec).

By using the conversion formula corresponding to the type of odor substance estimated by the odor substance estimation device 12 among the conversion formulas (1) to (3), the output change dV of the odor sensor 13d can be calculated. /dt, the concentration of the odorant can be determined.

[Overview of Functions of Devices 100, 200, and 300]
Next, various functions of the treated water quality target setting device 100, the powdered activated carbon injection control device 200, and the coagulant injection control device 300 will be described.

As described above, the treated water quality target setting device 100 sets target values for various physical quantities indicating the quality of the water to be treated. Specifically, as target values (target odorant concentrations) for various odorant concentrations, for example, the concentration of the odorant "dimethylisoborneol", the concentration of the odorant "geosmin", and the odorant "2,4-decadienal ] are set (target odorant concentration). In addition, as the target value of the soluble organic matter index value (target soluble organic matter index value), the target values of ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration (target ultraviolet absorbance, target fluorescence intensity, target dissolution organic carbon concentration) is set. In addition, a target value of turbidity (target turbidity) and a target value of hydrogen ion concentration index (target hydrogen ion concentration index) are set.

The powdered activated carbon injection control device 200 controls the powdered activated carbon injection device 21 that injects the powdered activated carbon into the water to be treated in the receiving well 20, as described above. This powdered activated carbon injection control device 200 takes in the data set by the treated water quality target setting device 100, and if necessary, the algae detection determination device 11, the odor substance estimation device 12, the odor substance concentration measurement device 13, the solubility Various data supplied from the organic substance indicator instrument set 14 and the flow meter 15 and data supplied from the coagulant injection control device 300 are taken in, and these data are used to inject into the water to be treated in the receiving well 20. Controls the injection rate of the powdered activated carbon used.

As described above, the coagulant injection control device 300 controls the coagulant injection device 31 that injects the coagulant into the water to be treated in the coagulant mixing tank 30 and the oxidant injection device 32 that injects the oxidant. . This coagulant injection control device 300 takes in data set by the treated water quality target setting device 100, and also takes in data supplied from the water quality meter set 10 and data supplied from the hydrogen ion concentration index measuring device 16, These data are used to control the injection rate of the coagulant and the injection rate of the oxidant to be injected into the water to be treated in the coagulant mixing pond 30 .

[Various Functions of Powdered Activated Carbon Injection Control Device 200]
Various functions provided in the powdered activated carbon injection control device 200 of the present embodiment are described below.

The powdered activated carbon injection control device 200 of this embodiment uses at least the concentration of the odorant measured by the odorant concentration measuring device 13 to determine the concentration of the odorant contained in the water to be treated in the receiving well 20 from the target odorant concentration. Calculate the powdered activated carbon injection rate (hereinafter referred to as the “odorant-compatible powdered activated carbon injection rate”) for Has the ability to control the amount.

In addition, the powdered activated carbon injection control device 200 uses the soluble organic substance index value (at least one of ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration) measured by the soluble organic substance index measurement set 14 to A powdered activated carbon injection rate (hereinafter referred to as “dissolved organic substance compatible powdered activated carbon injection rate”) for achieving a target residual rate of soluble organic substances in the water to be treated in the receiving well 20 is calculated. It has a function of comparing the injection rate of powdered activated carbon corresponding to the substance and the injection rate of powdered activated carbon corresponding to the odorant, and controlling the injection amount of powdered activated carbon to be injected into the water to be treated in the receiving well 20 according to the larger powdered activated carbon injection rate. .

Further, when the concentration of the odorant measured by the odorant concentration measuring device 13 is greater than the target concentration of the odorant, the powdered activated carbon injection control device 200 determines that the powdered activated carbon injection rate corresponding to the odorant is lower than the predetermined reference value. When the concentration of the odorant measured by the odorant concentration measuring device 13 is smaller than the target odorant concentration, the powdered activated carbon injection rate corresponding to the odorant is controlled to be smaller than the predetermined reference value. It has a function to control

In addition, the powdered activated carbon injection control device 200 has a function of calculating the powdered activated carbon injection rate corresponding to the odorant so as to compensate for the influence of the soluble organic substance that inhibits the adsorption of the odorant by the powdered activated carbon.

In addition, the powdered activated carbon injection control device 200 controls the powdered activated carbon injection process and the coagulant injection process so that the effect of the soluble organic substance that inhibits the adsorption of the odorant by the powdered activated carbon is complemented. It has a function to calculate the injection rate of powdered activated carbon for organic substances.

[Overview of operation]
Next, an example of the operation related to the powdered activated carbon injection control system of the first embodiment will be described with reference to the flowchart of FIG. 6A. However, the processing of each step described below does not necessarily have to be performed in the order shown in FIG. 6A, and the order of performing may be changed as appropriate.

In the treated water quality target setting device 100, various target values indicating the water quality of the water to be treated (target odorant concentration, target soluble organic substance index value (target ultraviolet absorbance, target fluorescence intensity, target soluble organic carbon concentration) At least one of them), the target turbidity, and the target hydrogen ion concentration index) are set (S101). The set target odorant concentration, target soluble organic matter index value, and target hydrogen ion concentration index data are taken into the powdered activated carbon injection control device 200, while the set target turbidity data are obtained from the coagulant injection. It is taken into the control device 300 .

On the other hand, the water quality instrument set 10 measures the quality of raw water (turbidity, alkalinity, water temperature, hydrogen ion concentration index). The measured water quality data is taken into the coagulant injection control device 300 . The algae detection and determination device 11 detects algae contained in the raw water and determines the type of algae. The odorant concentration measuring device 13 measures the concentration of the odorant contained in the raw water for the estimated type of odorant. At least one of the soluble organic substance index values of the organic carbon concentration is measured, and the flow rate of the raw water is measured by the flow meter 15 (S102). These measured data are taken into the powdered activated carbon injection control device 200 .

Further, the hydrogen ion concentration index measuring device 16 measures the hydrogen ion concentration index (pH value) of the mixed water in the coagulant mixing pond 30 (S103). Data of the measured hydrogen ion concentration index are taken into the coagulant injection control device 300 .

The coagulant injection control device 300 measures the turbidity, alkalinity, water temperature, and hydrogen ion concentration index of the raw water measured by the water quality instrument set 10, and the hydrogen ion concentration index measured by the hydrogen ion concentration index measuring device 16. is used to calculate the coagulant injection rate for achieving the target turbidity (S104), and the coagulant injection device is operated so that the coagulant is injected into the water to be treated in the coagulant mixing basin 30 according to the coagulant injection rate 31, the oxidant injector 32 is controlled so that the oxidant is also injected (S105). Note that the process of step S105 may be performed at the same time as the process of step S107, which will be described later, or after that.

The powdered activated carbon injection control device 200 uses the concentration of the odorant measured by the odorant concentration measuring device 13 to calculate the powdered activated carbon injection rate corresponding to the odorant for achieving the target concentration of the odorant, Using the soluble organic substance index value measured by the organic substance index instrument set 14, etc., the powdered activated carbon injection rate corresponding to the soluble organic substance for achieving the target soluble organic substance index value is calculated. The larger powdered activated carbon injection rate is calculated from the powdered activated carbon injection rate corresponding to the substance and the powdered activated carbon injection rate corresponding to the odorant (S106), and the powdered activated carbon is injected into the water to be treated in the receiving well 20 according to the powdered activated carbon injection rate. The powdered activated carbon injector 21 is controlled so that the powder is injected (S107). In this case, the powdered activated carbon injection control device 200, for example, calculates the injection amount of the powdered activated carbon per unit time from the calculated powdered activated carbon injection rate and the flow rate measured by the flow meter 15, and The powdered activated carbon injector 21 can be controlled so that activated carbon is injected into the water to be treated in the receiving well 20 .

Henceforth, the process from step S102 to step S107 is performed repeatedly.

[Specific example of setting processing and arithmetic processing]
Next, with reference to the flowchart of FIG. 6B, an example of operation showing details of setting processing and arithmetic processing related to the powdered activated carbon injection control system of the embodiment will be described. However, the processing of each step described below does not necessarily have to be performed in the order shown in FIG. 6B, and the order of performing may be changed as appropriate.

In step S1, in the treated water quality target setting device 100, various target values are set as tap water quality target values after water treatment.

Here, as an example of the target odorant concentrations of various odorants, the target odorant concentrations C _{2 −MIB} , _{C Geosmin} , _CD . A target turbidity Tu _D and a target hydrogen ion concentration index pH _D are also set.

Data on the set target odorant concentrations _{C 2-MIB} , C _Geosmin , and CD , the target ultraviolet absorbance UV _D , and the target hydrogen ion concentration index pH _D are taken into the powdered activated carbon injection control device 200. The data of the target turbidity Tu _D obtained is taken into the coagulant injection control device 300 .

In the following explanation, in order to make the explanation easier to understand, among various odorous substances “dimethylisoborneol”, “geosmin”, “2,4-decadienal”, etc., “dimethylisoborneol” is targeted. A calculation example is shown.

In step S2, the powdered activated carbon injection control device 200 calculates a target odorant residual rate, which is a target value of the odorant residual rate. Here, an example in which the target odor substance retention rate RC _2-MIB of dimethylisoborneol is calculated is shown as an example.

The powdered activated carbon injection control device 200 controls the target odorant concentration C _2-MIB of dimethylisoborneol set by the treated water quality target setting device 100 and the raw water odorant concentration C _R measured by the odorant concentration measuring device 13. , the target odor substance residual rate RC _2-MIB of dimethylisoborneol is calculated by the following equation.

RC2 _-MIB = C2 _-MIB / _CR (4)

In step S3, the powdered activated carbon injection control device 200 calculates the powdered activated carbon injection rate corresponding to the odorant, which is the powdered activated carbon injection rate that achieves the target odorant residual rate calculated in step S2. Here, as an example, an example in which the powdered activated carbon injection rate _Icar-D corresponding to the odorant corresponding to dimethylisoborneol is calculated is shown.

The powdered activated carbon injection control device 200 calculates the powdered activated carbon injection rate _Icar-D corresponding to the odorant for bringing the concentration of dimethylisoborneol to the target odorant concentration C _2-MIB using the following equation.

Icar _-D =f(RC2 _-MIB , _E260R , _DOCR , _FLR ) (5)

E260 _R in the above formula indicates the ultraviolet absorbance (abs/m) at a wavelength of 260 (nm) of raw water as an example of an index representing the ultraviolet absorbance UV _R of raw water.

The adsorption of odorants by powdered activated carbon is affected by the inhibition of adsorption by coexisting organic matter. Therefore, when calculating the powdered activated carbon injection rate _Icar-D corresponding to the odorant, it is desirable to perform a correction process to complement the influence. This will be described below with reference to FIGS. 7 to 9. FIG.

FIG. 7 is a graph showing test results by the inventors when dimethylisoborneol or geosmin was added to the raw water of a certain water purification plant and the same powdered activated carbon injection treatment was performed.

The graph of FIG. 7 shows the relationship between the general powdered activated carbon injection rate _Icar (mg/L) and the odorant residual rate RC (%) of each odorant. From this graph, it can be seen that even when the same raw water and the same powdered activated carbon are used, the adsorption characteristics differ depending on the type of odorant.

FIG. 8 is a graph showing test results when dimethylisoborneol was added to pure water, and humic acid and fulvic acid were added at different mixing ratios, and powdered activated carbon was injected. FIG. 9 is a graph showing test results when geosmin was added to pure water, and humic acid and fulvic acid were added at different mixing ratios, and powdered activated carbon was injected.

The graphs of FIGS. 8 and 9 show the powdered activated carbon injection rate I _car (mg/L) and the odorant residual rate RC _2-MIB (%) of dimethylisoborneol or the odorant residual rate RC _Geosmin (%) of geosmin. relationship is shown. All test results are the results of rapid stirring treatment with a jar tester at 150 (rpm) for 60 minutes with a total additive concentration of TOC ≈ 3.0 (mg/L). As can be seen from these graphs, the adsorption of odorants by powdered activated carbon is affected differently by the structure of coexisting organic matter (humic acid/fulvic acid ratio).

Therefore, when calculating the powdered activated carbon injection rate _Icar-D corresponding to odorous substances, the soluble organic substance index value (here, for example, the ultraviolet absorbance E260 _R ), which is an index of coexisting organic substances, the soluble organic carbon concentration DOC It is desirable to consider the ratio of _R , fluorescence intensity FL _R , and the like. Furthermore, since the effect of coexisting organic matter differs depending on the target odorant, by including a correction coefficient for each odorant in the function of formula (5) for multiple types of assumed odorants, the odor It is possible to calculate an appropriate powdered activated carbon injection rate corresponding to the odorous substance estimated by the substance estimating device 12 .

In step S4, the powdered activated carbon injection control device 200 calculates a target soluble organic substance residual ratio, which is a target value of the soluble organic substance residual ratio. Here, an example in which the target ultraviolet absorbance residual rate RUV _T is calculated using the ultraviolet absorbance as an example of the soluble organic substance index value is shown.

The powdered activated carbon injection control device 200 calculates the target UV absorbance residual rate RUV _T from the target UV absorbance UV _D set by the treated water quality target setting device 100 and the UV absorbance UV _R of the raw water measured by the UV absorbance meter 14a. is calculated by the following formula.

RUV _T = UV _D /UV _R (6)

In step S5, the coagulant injection rate I _pacl for achieving the target turbidity Tu _D is calculated in the coagulant injection control device 300 .

The coagulant injection control device 300 controls the target turbidity Tu _D set by the treated water quality target setting device 100, the turbidity meter 10a, the alkalinity meter 10b, the water temperature meter 10c, and the hydrogen ion concentration index in the water quality meter set 10. Raw water turbidity Tu _R , raw water alkalinity Alk _R , water temperature T _R , and hydrogen ion concentration index pH _R measured by the total 10d, and the hydrogen ion concentration index measuring device 16 installed in the coagulant mixing pond 30. Calculate the flocculant injection rate I _pacl to achieve the target turbidity Tu _D using the calculated mixed pond pH _F.

I _pacl = _f (Tu _D , Tu _R , Alk _R , TR , pH _R , pH _F ) (7)

In step S6, the coagulant injection control device 300 controls the coagulant injection device 31 so that the coagulant is injected into the water to be treated in the coagulant mixing tank 30 according to the calculated coagulant injection rate I _pacl .

In step S7, the powdered activated carbon injection control device 200 calculates the soluble organic substance residual ratio after the coagulation treatment, which is the residual ratio of the soluble organic substances remaining after the coagulation treatment. Here, as an example, an example in which the post-aggregation treatment ultraviolet light absorbance residual rate RUV _pacl is calculated is shown.

The powdered activated carbon injection control device 200 calculates the residual rate of the soluble organic substances remaining after the flocculation treatment with the flocculant injection rate I _pacl as the post-flocculation ultraviolet absorbance residual rate RUV _pacl .

The removal of soluble organic substances by flocculation is also affected by the structure of organic substances. Therefore, in calculating the post-aggregation UV absorbance residual rate RUV _pacl , it is desirable to perform a correction process to complement the influence. This will be described below with reference to FIG.

FIG. 10 shows that after the inventors added a flocculant to the water to be treated, which was adjusted to the raw water soluble organic carbon concentration _DOCR = 2.5 (mg / L) and the mixed water pH _F = 6.5, It is a graph which shows the test result at the time of rapid stirring processing for 10 minutes at rotation speed 150 (rpm), and slow stirring processing at rotation speed 80 (rpm) for 60 minutes.

Also in this test, humic acid and fulvic acid were added as soluble organic substances at different mixing ratios. The graph of FIG. 10 shows the relationship between the coagulant injection rate I _pacl (mg/L) and the post-aggregation UV absorbance residual rate RUV _pacl (%). The post-aggregation UV absorbance residual rate RUV _pacl on the vertical axis indicates a value obtained by dividing the post-aggregation UV absorbance UV _pacl by the UV absorbance UV _R of the raw water.

Fig. 10 shows the case of 100% humic acid, a mixture of 50% humic acid/50% fulvic acid, and 100% fulvic acid. was found to receive

Therefore, the powdered activated carbon injection control device 200 calculates the post-aggregation UV absorbance residual rate RUV _pacl using the relationship shown in FIG.

RUV _pacl = α × I _pacl + β (8)

β=f( _pHF , _UVR , _DOCR , _FLR ) (9)

Here, I _pacl is the coagulant injection rate (mg/L), α is the injection rate constant (−), and β is the intercept corresponding to I _pacl =0 (mg/L) in the graph of FIG.

β is the mixed pond hydrogen ion concentration index pH _F , ultraviolet absorbance UV _R (abs/cm) (here, for example, ultraviolet absorbance E260 _R at a wavelength of 260 (nm) of raw water), soluble organic carbon concentration DOC _R (mg /L), and the fluorescence intensity FL _R of raw water (here, for example, fluorescence intensity at a fluorescence wavelength of 425 (nm) with respect to an excitation wavelength of 345 (nm)).

In step S8, the powdered activated carbon injection control device 200 calculates the post-adsorption treatment soluble organic substance residual ratio, which is the residual ratio of the soluble organic substances remaining after the adsorption treatment when the adsorption treatment is performed. Here, an example in which the post-adsorption treatment ultraviolet absorbance residual rate RUV _car is calculated using the ultraviolet absorbance as an example of the soluble organic substance index value is shown.

The UV absorbance residual ratio after adsorption treatment RUV _car is the residual ratio of soluble organic substances remaining after the adsorption treatment when the powdered activated carbon treatment is performed alone, and the powdered activated carbon treatment and the aggregation treatment were performed together. It is different from the residual rate of soluble organic substances remaining after adsorption treatment in some cases. This will be explained below.

The ultraviolet absorbance when the powdered activated carbon treatment and the flocculation treatment are used together is defined as the ultraviolet absorbance after combined treatment RUV _car/pacl . The UV absorbance after combined treatment RUV _car/pacl is defined by the following equation using the UV absorbance residual rate after adsorption process RUV _car , the UV absorbance after coagulation process RUV _pacl , and the combined treatment factor F _DOM .

RUV _car/pacl = _FDOM x RUV _car x RUV _pacl (10)

F _DOM is a coefficient that indicates the effect of combined treatment (combined treatment coefficient) _. It is obtained by dividing by the product of _car and the post-aggregation UV transmittance residual rate RUV _pacl when the aggregation treatment is performed alone.

Here are the results of our studies on the combined treatment factor F _DOM .

Fig. 11 shows that powdered activated carbon treatment is rapidly stirred at 150 (rpm) for 60 minutes, the hydrogen ion concentration index (pH) is adjusted to a predetermined value, a flocculant is added, and the mixture is stirred at 150 (rpm) for 10 minutes. It is a graph which shows the test result at the time of rapid stirring and slow stirring processing for 60 minutes at rotation speed 80 (rpm).

As shown in FIG. 11, the combined treatment factor F _DOM varies greatly depending on the mixing ratio of the added organic substances humic acid and _fulvic acid. is smaller than the value obtained by multiplying the UV absorbance residual rate after adsorption treatment by the UV absorbance residual rate after aggregation treatment (RUV _car × RUV _pacl ) (F _DOM < 1), and there is an effect of promoting the treatment when used in combination. On the other hand, when the proportion of fulvic acid increases, the residual UV absorbance ratio after combined treatment, RUV _car/pacl , is the value obtained by multiplying the residual UV absorbance ratio after adsorption treatment and the residual UV absorbance ratio after flocculation treatment (RUV _car × RUV _pacl ) (F _DOM ≧1), indicating an inhibitory effect of the combined treatment.

Here, in FIG. 11, when the relationship between the combined treatment coefficient F _DOM and the coagulant injection rate I _pacl for each mixing ratio of humic acid and fulvic acid is approximated by the following equation, the different coefficient f and index n for each mixing ratio can be obtained. be done.

F _DOM = f × I _pacl ⁿ (11)

Therefore, as a result of examining the relationship between the specific absorbance SUVA defined by the following equation as an index close to the mixing ratio of humic acid and fulvic acid in the soluble organic substances contained in raw water and the coefficient f, the results shown in FIG. 12 were obtained. rice field.

SUVA = E260 _R /DOC _R (abs.L/m.mg) (12)

Here, E260 _R is the ultraviolet absorbance (abs/m) at a wavelength of 260 (nm) of the raw water, and DOC _R is the soluble organic carbon concentration (mg/L) of the raw water.

The graph of FIG. 12 shows the relationship between the specific absorbance SUVA (abs·L/m·mg) and the coefficient f. From this graph, it can be seen that the coefficient f can be expressed as a function of the specific absorbance SUVA.

Therefore, in step S8, the powdered activated carbon injection control device 200 sets the target ultraviolet absorbance residual rate RUV _T to the post-combined treatment ultraviolet absorbance residual rate RUV _car/pacl , and calculates the post-adsorption treatment ultraviolet absorbance residual rate RUV _car according to the following equation: demand.

RUV _T = RUV _car/pacl = _FDOM x RUV _car x RUV _pacl (13)

RUV _car = RUV _T / ( _FDOM x RUV _pacl ) (14)

In step S9, the powdered activated carbon injection control device 200 calculates the powdered activated carbon injection rate corresponding to the soluble organic substance, which is the powdered activated carbon injection rate that achieves the soluble organic substance residual rate after the adsorption treatment calculated in step S8. Here, as an example of the soluble organic substance index value, an example of calculating the powdered activated carbon injection rate _Icar-UV corresponding to the soluble organic substance using the ultraviolet absorbance is shown.

The powdered activated carbon injection control device 200 calculates the powdered activated carbon injection rate _Icar-UV corresponding to the soluble organic substance by the following equation.

Icar _-UV =f( _KUV , _RUVcar , _E260R , _DOCR ) (15)

Here, K _UV is an adsorption constant determined by the performance of the powdered activated carbon and the properties of the substance to be adsorbed, and is a value that is determined and set in advance.

In step S10, in the powdered activated carbon injection control device 200, the powdered activated carbon injection rate _Icar-D for odorous substances calculated in step S3 and the powdered activated carbon injection rate _Icar-UV for soluble organic substances calculated in step S9 are calculated. The larger one is adopted as the powdered activated carbon injection rate _Icar .

When the powdered activated carbon injection rate _Icar-UV for soluble organic substances is larger, in steps S11A and S12, the powdered activated carbon injection rate _Icar-UV for soluble organic substances is set as the powdered activated carbon injection rate _Icar . The powdered activated carbon injection device 21 is controlled so that the powdered activated carbon is injected into the water to be treated in the receiving well 20 according to the powdered activated carbon injection rate _Icar .

On the other hand, when the powdered activated carbon injection rate _Icar-D corresponding to the odorous substance is larger, in steps S11B and S12, the powdered activated carbon injection rate _Icar-D corresponding to the odorant is made the powdered activated carbon injection rate _Icar . The powdered activated carbon injector 21 is controlled so that the powdered activated carbon is injected into the water to be treated in the receiving well 20 according to the injection rate _Icar .

According to the first embodiment, the algae detection determination device 11, the odorant estimation device 12, and the odorant concentration measurement device 13 are used to identify the type of odorant to be removed by the powdered activated carbon, and to identify the odorant. Since the concentration can be determined, the powdered activated carbon injection control device 200 can determine the optimum powdered activated carbon injection rate for achieving the target concentration based on the concentration of the odorant. Furthermore, by setting concentration target values for various assumed odorous substances in advance, it is possible to flexibly respond to changes in odorous substances caused by changes in the algae that live in the raw water. It is possible to determine the optimum injection rate of powdered activated carbon according to the condition, suppress wasteful injection of powdered activated carbon, and realize economical water treatment control.

In addition, according to the first embodiment, by performing powdered activated carbon injection in consideration of the effect of combined use of powdered activated carbon and a flocculant on the removal of soluble organic substances and the removal of odorous substances, The amount of powdered activated carbon can be greatly reduced, and the injection rate of powdered activated carbon can be controlled appropriately and with high precision. As a result, it is possible to prevent the concentration of soluble organic substances in the filtered water and the residual ratio of odorous substances from exceeding the target due to insufficient injection of powdered activated carbon, and waste of chemical costs due to excessive injection.

In the first embodiment, the residual rate RUV of the ultraviolet absorbance E260 at a wavelength of 260 (nm) was used as a representative index of soluble organic substances. By using the fluorescence intensity FL at a fluorescence wavelength of 425 (nm) with respect to (nm), it is possible to universally cope with fluctuations in raw water and different water sources.

Further, in the first embodiment, an example of monitoring the soluble organic substances in the raw water with three types of instruments: an ultraviolet absorbance meter 14a, a fluorescence intensity meter 14b, and a soluble organic carbon concentration meter (DOC meter) 14c is shown. However, in the case of a single raw water system where there is little variation in the composition of organic matter in the raw water, one representative instrument may be used to obtain another indicator by a conversion formula. An example of a conversion formula when using an ultraviolet absorbance meter as a representative instrument is shown below.

DOC _R = a x UV _R x b (16)

FL _R = c x UV _R x d (17)

here,
DOC _R : Concentration of soluble organic carbon in raw water (mg/L)
FL _R : Fluorescence intensity of raw water (-)
UV _R : UV absorbance of raw water (abs/cm)
a: UV absorbance - dissolved organic carbon concentration conversion coefficient b: UV absorbance - dissolved organic carbon concentration conversion constant c: UV absorbance - fluorescence intensity conversion coefficient d: UV absorbance - fluorescence intensity conversion constant By using the conversion formula for , even if only one instrument is installed, it is possible to obtain the same effect as in the case of monitoring soluble organic substances in raw water with three instruments.

<Second embodiment>
Next, a second embodiment will be described. Here, the description of the parts common to the above-described first embodiment will be omitted, and the different parts will be mainly described.

The configuration of the water treatment system is the same as the configuration shown in FIG. However, as described below, the configuration related to the odor sensor in the odor substance concentration measuring device 13 is different.

FIG. 13 is a diagram showing an example of the configuration of the odorant concentration measuring device 13 according to the second embodiment. 13, elements common to those in FIG. 4 are given the same reference numerals.

In the first embodiment described above, the case where the odor sensor provided in the odor substance concentration measuring device 13 in FIG. 4 is of one type has been described. An odor sensor that reacts to musty odor substances generated from algae and an odor sensor that does not react to musty odor substances but reacts to oily odors is provided.

In the example of FIG. 13, the odor substance concentration measuring device 13 is equipped with a plurality of odor sensors 13d-1, 13d-2 and 13d-3.

The odor sensors 13d-1, 13d-2, and 13d-3 detect different substances. For example, the odor sensor 13d-1 is a sensor designed to selectively detect dimethylisoborneol, the odor sensor 13d-2 is a sensor designed to selectively detect geosmin, the odor sensor 13d- A sensor 3 is set to selectively detect an oil odor without reacting to a musty odor substance.

According to the second embodiment, by installing a sensor that is optimally designed according to the odorant to be detected, even if the type of odorant contained in the raw water changes, the odorant estimation device 12 can perform estimation. Based on the results, the optimum sensor is selected, enabling highly sensitive concentration measurement. Furthermore, by installing at least one of the multiple sensors that selectively detects oil odors, it is possible to immediately issue an alarm in the event of an oil spill into a water source. In addition, it becomes possible to inject powdered activated carbon in an emergency as needed, which greatly improves the ability to deal with contaminants in raw water.

<Third Embodiment>
Next, a third embodiment will be described. Here, the description of the parts common to the above-described first embodiment will be omitted, and the different parts will be mainly described.

[composition]
FIG. 14 is a diagram showing an example of the configuration of a water treatment system according to the third embodiment. In addition, in FIG. 14, elements common to those in FIG. 1 are given the same reference numerals.

In the water treatment system of the third embodiment, the powdered activated carbon injection device is not one, but has a two-stage configuration, and the powdered activated carbon injection device 21 a of the first stage is configured to inject the powdered activated carbon into the receiving well 20 . , and a second-stage powdered activated carbon injection device 21 b is installed so as to inject powdered activated carbon into the coagulant mixing pond 30 . Furthermore, the odorant concentration measuring device 13 is not installed in the pipe 2, but is installed in the pipe 3 from the receiving well 20 to the coagulant mixing pond 30, which is different from the case of the first embodiment. . Therefore, the odorant concentration measuring device 13 measures the concentration of the odorant contained in the test water sampled from the pipe from the receiving well 20 to the coagulant mixing pond 30, that is, the odor contained in the treated water after powdered activated carbon injection treatment. It will measure the concentration of the substance. Along with this, some functions and operations in the powdered activated carbon injection control device 200 are different from those of the first embodiment.

The powdered activated carbon injection control device 200 of the third embodiment measures the soluble organic substance index value (at least one of ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration) measured by the soluble organic substance index measurement set 14. is used to calculate the powdered activated carbon injection rate corresponding to soluble organic substances for achieving the target residual rate of soluble organic substances in the water to be treated in the receiving well 20, and this powdered activated carbon injection rate corresponding to soluble organic substances is calculated. According to the above, the injection amount of powdered activated carbon to be injected into the treated water of the receiving well 20 is controlled, and the concentration of the odorant contained in the treated water of the receiving well 20 is adjusted to the target concentration. It has a function of controlling the amount of powdered activated carbon to be injected into the water to be treated in the coagulant mixing pond 30 according to the rate.

Further, in the powdered activated carbon injection control device 200 of the third embodiment, when the concentration of the odorant measured by the odorant concentration measuring device 13 is higher than the target concentration, the powdered activated carbon injection rate corresponding to the odorant is set in advance. On the other hand, if the concentration of the odorant measured by the odorant concentration measuring device 13 is smaller than the target concentration, the injection rate of powdered activated carbon corresponding to the odorant is lower than the predetermined reference value. has a function of controlling (feedback control) so that the

[Overview of operation]
Next, an example of operations related to the powdered activated carbon injection control system of the third embodiment will be described with reference to the flowchart of FIG. 15A. However, the processing of each step described below does not necessarily have to be performed in the order shown in FIG. 15A, and the order of performing may be changed as appropriate. The following description will focus on the portions that are different from FIG. 6A.

The processing of step S101 is the same as the processing described with reference to FIG. 6A.

The process of step S102' differs from the process of step S102 described with reference to FIG. 6A in that the concentration of odorants in the raw water is not measured.

In step S201, the odorant concentration measuring device 13 measures the concentration of the odorant contained in the treated water after the powdered activated carbon injection treatment, targeting the type of odorant estimated by the odorant estimation device 12 .

The processing of steps S104 and S105 is the same as the processing described with reference to FIG. 6A.

The processing of steps S106' and S107' is different from the processing of steps S106 and S107 described with reference to FIG. 6A.

In step S106', the powdered activated carbon injection control device 200 uses the concentration of the odorant measured by the odorant concentration measuring device 13 to calculate the powdered activated carbon injection rate for achieving the target odorant concentration. At the same time, using the soluble organic substance index value measured by the soluble organic substance index meter set 14, etc., the soluble organic substance corresponding powdered activated carbon injection rate for achieving the target soluble organic substance index value is calculated. However, the details of the processing at that time are different from step S106 described with reference to FIG. 6A. Details of the processing will be described later with reference to the flowchart of FIG. 15B.

In step S107′, the powdered activated carbon injection control device 200 controls the injection amount of powdered activated carbon injected into the water to be treated in the receiving well 20 according to the calculated injection rate of powdered activated carbon corresponding to soluble organic substances. The amount of powdered activated carbon to be injected into the water to be treated in the coagulant mixing tank 30 is controlled according to the corresponding powdered activated carbon injection rate.

Thereafter, the processing from step S102' to step S107' is repeated.

[Specific example of setting processing and arithmetic processing]
Next, with reference to the flowchart of FIG. 15B, an example of operation showing details of setting processing and arithmetic processing related to the powdered activated carbon injection control system of the embodiment will be described. However, the processing of each step described below does not necessarily have to be performed in the order shown in FIG. 15B, and the order of performing may be changed as appropriate.
Below, it demonstrates centering on a different part from FIG. 6B.

The processing of step S1 is the same as the processing described with reference to FIG. 6B.

The processing in step _S2 is the same as the processing described in FIG. It differs from the process described in FIG. 6B in that it is the concentration of odorant that is

The processes of steps S2 and S3' are different from the processes of steps S2 and S3 described in FIG. 6B, and are performed after the processes of steps S4 to S9, for example.

The powdered activated carbon injection control device 200 calculates the powdered activated carbon injection rate _Icar-UV corresponding to soluble organic substances in step S9, and determines the injection rate of the receiving well 20 according to this powdered activated carbon injection rate _Icar-UV corresponding to soluble organic substances in step S12a. The powdered activated carbon injector 21a is controlled so that the powdered activated carbon is injected into the water to be treated. Next, in step S2, the target odorant concentration C _2-MIB of dimethylisoborneol set by the treated water quality target setting device 100 and the raw water odorant concentration C _R measured by the odorant concentration measuring device 13 Then, the target odor substance residual rate RC _2-MIB of dimethylisoborneol is calculated by the following formula.

RC2 _-MIB =C2 _-MIB /C _R (18)

Next, in step S3′, the powdered activated carbon injection rate _Icar-D corresponding to the odorous substance for making dimethylisoborneol the target odorant concentration C _2-MIB is calculated by the following equation.

_Icar-D =f(RC2 _-MIB ) (19)

Next, in step S12b, the powdered activated carbon injection device 21b is controlled so that the powdered activated carbon is injected into the water to be treated in the coagulant mixing pond 30 according to this powdered activated carbon injection rate C _R corresponding to the odorant.

According to the third embodiment, the powdered activated carbon injection control device 200 injects the powdered activated carbon so that the powdered activated carbon is injected into the water to be treated in the receiving well 20 according to the dissolved organic substance-compatible powdered activated carbon injection rate _Icar-UV . In addition to controlling the device 21a, the flocculant mixing pond 30 is controlled according to the powdered activated carbon injection rate I _car-D corresponding to the odorant calculated using the concentration C _R of the odorant contained in the treated water after the powdered activated carbon injection treatment. The powdered activated carbon injection device 21b is controlled (feedback controlled) so that the powdered activated carbon is injected into the water to be treated. It is possible to compensate by injecting powdered activated carbon with the powdered activated carbon injection device 21b, and it is possible to compensate for the adsorption inhibition by the coexisting organic matter, eliminate errors due to prediction of the inhibitory effect in advance, and prevent excess or deficiency of powdered activated carbon injection. .

As described in detail above, according to each embodiment, the injection rate of the powdered activated carbon can be optimized.

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 novel 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 modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and equivalents thereof.

1 Water treatment facility 2, 3, 4 Piping 10 Water quality meter set 10a Turbidity meter 10b Alkalinity meter 10c Water temperature meter 10d Hydrogen ion concentration index meter 11 Algae detection determination Apparatus 11a Flow cell 11b Lighting 11c Camera 11f Calculator 11g Display device 12 Odor substance estimation device 13 Odor substance concentration measurement device 13a Odor substance extraction tank 13a-1 Overflow Tray 13a-2 Raw water introduction pipe 13a-3 Heater 13a-4 Air supply fan 13b Dehumidifier 13c Odor sensor cell 13d Odor sensor head (odor sensor) 13f Odor substance concentration Arithmetic device 16... Hydrogen ion concentration index measuring instrument (pH measuring instrument) 20... Receiving well 21, 21a, 21b... Powdered activated carbon injector 30... Flocculant mixing pond 30a... Stirrer 31... Flocculant injector 32... Oxidant injection device 40... Coagulation/sedimentation tank 100... Treated water quality target setting device 200... Powdered activated carbon injection control device 300... Flocculant injection control device.

Claims (19)

Algae detection determination means for detecting algae contained in raw water and determining the type of the algae;
odorant estimation means for estimating the type of odorant emitted by the algae from the algae species determined by the algae detection determination means;
odorant concentration measuring means for measuring the concentration of the odorant contained in the raw water or the treated water after the powdered activated carbon injection treatment, targeting the type of the odorant estimated by the odorant estimation means;
Using at least the concentration of the odorant measured by the odorant concentration measuring means, the powdered activated carbon injection rate corresponding to the odorant is calculated to bring the concentration of the odorant contained in the treated water of the receiving well to the target concentration. and a powdered activated carbon injection control means for controlling the amount of powdered activated carbon injected into the water to be treated in the receiving well or the water to be treated in the coagulant mixing basin based on the powdered activated carbon injection rate corresponding to the odorant. Activated carbon injection control system. The odorant estimation means is
Information indicating the relationship between various types of algae and odorous substances generated from these algae is provided, and based on the information, the types of odorous substances contained in the raw water are selected from the types of algae determined by the algae detection determination means. to estimate
The powdered activated carbon injection control system of claim 1. The odorant concentration measuring means comprises:
Information indicating the relationship between the output change of the odor sensor provided in the odorant concentration measuring means and the odorant concentration for each of various odorous substances, and among the information, the odorant estimated by the odorant estimation means Determining the concentration from the output change measured by the odor sensor based on information corresponding to the type of
The powdered activated carbon injection control system according to claim 1 or 2. The odorant concentration measuring means comprises:
An odor sensor that reacts to a musty odor substance generated from algae, and an odor sensor that does not react to the musty odor substance but reacts to an oil odor,
The powdered activated carbon injection control system according to any one of claims 1 to 3. Further comprising soluble organic substance index measuring means for measuring at least one of ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration of the raw water as a soluble organic substance index value,
The powdered activated carbon injection control means includes:
Using the soluble organic matter index value measured by the soluble organic matter index measuring means, soluble organic matter correspondence for achieving a target soluble organic matter residual rate in the water to be treated in the receiving well Calculate the powdered activated carbon injection rate,
The powdered activated carbon injection rate for the soluble organic substance and the powdered activated carbon injection rate for the odorous substance are compared, and the larger powdered activated carbon injection rate is taken as the powdered activated carbon injection rate. Controlling the amount of powdered activated carbon injected into the water to be treated,
The powdered activated carbon injection control system according to any one of claims 1 to 4. The odorant concentration measuring means comprises:
Measuring the concentration of odorants contained in the raw water,
The powdered activated carbon injection control means includes:
When the concentration of the odorant measured by the odorant concentration measuring means is higher than the target concentration, the powdered activated carbon injection rate corresponding to the odorant is controlled to be greater than a predetermined reference value, and the concentration of the odorant is controlled. If the concentration of the odorant measured by the measuring means is lower than the target concentration, the powdered activated carbon injection rate corresponding to the odorant is controlled to be smaller than a predetermined reference value.
The powdered activated carbon injection control system according to claim 5. Further comprising soluble organic substance index measuring means for measuring at least one of ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration of the raw water as a soluble organic substance index value,
The powdered activated carbon injection control means includes:
Using the soluble organic matter index value measured by the soluble organic matter index measuring means, soluble organic matter correspondence for achieving a target soluble organic matter residual rate in the water to be treated in the receiving well Calculate the powdered activated carbon injection rate,
controlling the amount of powdered activated carbon to be injected into the water to be treated in the receiving well according to the powdered activated carbon injection rate for soluble organic substances;
Controlling the amount of powdered activated carbon to be injected into the water to be treated by injecting the coagulant according to the odorant-compatible powdered activated carbon injection rate;
The powdered activated carbon injection control system according to any one of claims 1 to 4. The odorant concentration measuring means comprises:
Measuring the concentration of odorants contained in the treated water after the powdered activated carbon injection treatment,
The powdered activated carbon injection control means includes:
When the concentration of the odorant measured by the odorant concentration measuring means is higher than the target concentration, the powdered activated carbon injection rate corresponding to the odorant is controlled to be greater than a predetermined reference value, and the concentration of the odorant is controlled. If the concentration of the odorant measured by the measuring means is lower than the target concentration, the powdered activated carbon injection rate corresponding to the odorant is controlled to be smaller than a predetermined reference value.
The powdered activated carbon injection control system of claim 7. The powdered activated carbon injection control means includes:
Calculate the powdered activated carbon injection rate corresponding to the odorant so that the effect of the soluble organic substance that inhibits the adsorption of the odorant by the powdered activated carbon is complemented;
The powdered activated carbon injection control system according to any one of claims 1-8. The powdered activated carbon injection control means includes:
When powdered activated carbon injection treatment and coagulant injection treatment are used together, the powdered activated carbon injection rate corresponding to the dissolved organic substance is calculated so that the influence of the dissolved organic substance that inhibits the adsorption of the odorant by the powdered activated carbon is complemented. do,
The powdered activated carbon injection control system according to any one of claims 5-8. Detecting algae contained in the raw water by the algae detection and determination means to determine the type of the algae;
estimating the type of odorant emitted by the algae from the determined type of algae by the odorant estimating means;
measuring the concentration of the odorant contained in the raw water or the treated water after powdered activated carbon injection treatment for the estimated type of the odorant by the odorant concentration measuring means;
The powdered activated carbon injection control means uses at least the measured concentration of the odorous substance to calculate the powdered activated carbon injection rate corresponding to the odorous substance for bringing the concentration of the odorant contained in the treated water of the receiving well to the target concentration. and controlling the amount of powdered activated carbon to be injected into the water to be treated in the receiving well or the water to be treated in the coagulant mixing pond based on the powdered activated carbon injection rate corresponding to the odorant. . Targeting the types of odorous substances emitted by algae contained in raw water, the results of measuring the concentration of odorous substances contained in the raw water or the treated water after powdered activated carbon injection treatment are taken in, and at least the concentration of the odorous substances is used to determine the Calculate the powdered activated carbon injection rate corresponding to the odorous substance to bring the concentration of the odorant contained in the treated water of the water well to the target concentration, and based on the powdered activated carbon injection rate corresponding to the odorant, the treated water of the receiving well or A powdered activated carbon injection control device comprising powdered activated carbon injection control means for controlling the amount of powdered activated carbon injected into water to be treated in a flocculant mixing pond. The powdered activated carbon injection control means includes:
A result obtained by measuring at least one of the raw water ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration as a soluble organic substance index value is taken in, and the soluble organic substance index value is used to determine the receiving well for treatment. Calculate the powdered activated carbon injection rate for soluble organic substances to achieve the target residual rate of soluble organic substances in water,
The powdered activated carbon injection rate for the soluble organic substance and the powdered activated carbon injection rate for the odorous substance are compared, and the larger powdered activated carbon injection rate is taken as the powdered activated carbon injection rate. Controlling the amount of powdered activated carbon injected into the water to be treated,
13. The powdered activated carbon injection control device according to claim 12. The powdered activated carbon injection control means includes:
When the measured concentration of the odorant is higher than the target concentration, the injection rate of the powdered activated carbon corresponding to the odorant is controlled to be greater than a predetermined reference value, and the measured concentration of the odorant reaches the target. If the concentration is less than the concentration of , the powdered activated carbon injection rate corresponding to the odorant is controlled to be smaller than a predetermined reference value.
14. The powdered activated carbon injection control device of claim 13. The powdered activated carbon injection control means includes:
A result obtained by measuring at least one of the raw water ultraviolet absorbance, fluorescence intensity, and soluble organic carbon concentration as a soluble organic substance index value is taken in, and the soluble organic substance index value is used to determine the receiving well for treatment. Calculate the powdered activated carbon injection rate for soluble organic substances to achieve the target residual rate of soluble organic substances in water,
controlling the amount of powdered activated carbon to be injected into the water to be treated in the receiving well according to the powdered activated carbon injection rate for soluble organic substances;
Controlling the amount of powdered activated carbon to be injected into the water to be treated by injecting the coagulant according to the odorant-compatible powdered activated carbon injection rate;
13. The powdered activated carbon injection control device according to claim 12. The powdered activated carbon injection control means includes:
When the measured concentration of the odorant is higher than the target concentration, the injection rate of the powdered activated carbon corresponding to the odorant is controlled to be greater than a predetermined reference value, and the measured concentration of the odorant reaches the target. If the concentration is less than the concentration of , the powdered activated carbon injection rate corresponding to the odorant is controlled to be smaller than a predetermined reference value.
16. The powdered activated carbon injection control device of claim 15. The powdered activated carbon injection control means includes:
Calculate the powdered activated carbon injection rate corresponding to the odorant so that the effect of the soluble organic substance that inhibits the adsorption of the odorant by the powdered activated carbon is complemented;
17. A powdered activated carbon injection control device according to any one of claims 12-16. The powdered activated carbon injection control means includes:
When powdered activated carbon injection treatment and coagulant injection treatment are used together, the powdered activated carbon injection rate corresponding to the dissolved organic substance is calculated so that the influence of the dissolved organic substance that inhibits the adsorption of the odorant by the powdered activated carbon is complemented. do,
17. A powdered activated carbon injection control device according to any one of claims 13-16. to the computer,
Targeting the types of odorous substances emitted by algae contained in raw water, the results of measuring the concentration of odorous substances contained in the raw water or the treated water after powdered activated carbon injection treatment are taken in, and at least the concentration of the odorous substances is used to determine the A function to calculate the injection rate of powdered activated carbon corresponding to odorous substances in order to bring the concentration of odorous substances contained in well water to the target concentration;
and a function of controlling the amount of powdered activated carbon to be injected into the water to be treated in the receiving well or the water to be treated in the coagulant mixing pond based on the powdered activated carbon injection ratio for odorants.

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