Powdered activated carbon injection rate calculation device, powdered activated carbon injection control system, powdered activated carbon injection rate calculation method, and computer program

Abstract

The present invention provides a powder activated carbon injection rate calculation device for determining an appropriate injection rate of powder activated carbon for water to be treated that contains two or more odor-causing substances. [Solution] The powder activated carbon injection rate calculation device according to this embodiment includes a ratio calculation unit 31 that calculates the ratio between the concentration equivalent value of a first odor component contained in the raw water and the concentration equivalent value of a second odor component, and an injection rate calculation unit 32 that calculates the powder activated carbon injection rate using the concentration of the odor component selected according to the result of comparing the ratio value with a threshold value.

Description

[Technical Field]

[0001] Embodiments of the present invention relate to a powder activated carbon injection rate calculation device, a powder activated carbon injection control system, a powder activated carbon injection rate calculation method, and a computer program. [Background technology]

[0002] Treated water (raw water for water treatment plants) taken from rivers, lakes, reservoirs, etc., contains odor-causing substances, dissolved organic matter such as humic acid and fulvic acid, and turbidity particles such as inorganic fine particles. Dissolved organic matter, including odor-causing substances and humic substances such as humic acid and fulvic acid, must be removed because water standards are set by the Water Supply Act.

[0003] In recent years, in particular, due to the effects of climate change, odors such as moldy smells produced by algae and other organisms in the raw water have become a problem at many water treatment plants. When algae and actinomycetes inhabit the raw water at water treatment plants, substances known to cause moldy odors, such as 2-MIB and geosmin, are generated. The standard value for each of these substances is set at 10 ng / L by the Water Supply Act, and their removal is required.

[0004] Powdered activated carbon is used to remove odor-causing substances. Because powdered activated carbon has low injection equipment costs, it is easily adopted as a chemical used in facilities such as water treatment plants. However, as a chemical, powdered activated carbon is expensive, resulting in high running costs, and therefore, reducing its usage is desired.

[0005] In many water treatment plants, the powdered activated carbon used to remove the above-mentioned moldy odor-causing substances is determined based on quick reference tables and empirical formulas using estimated odor concentrations from sensory tests or measured odor concentrations from GC / MS (gas chromatography-mass spectrometry), or by jar tests and sensory checks of the treated water.

[0006] A jar test is a method for determining the amount of activated carbon powder needed to reduce the odor concentration after treatment to below a target level by collecting water to be treated in multiple beakers, injecting different amounts of activated carbon powder into each of the collected water samples, allowing them to react for a certain period of time, and then measuring the concentration of odor substances after treatment.

[0007] However, the method of determining the injection rate of powdered activated carbon by jar testing requires a certain amount of time to perform the jar test. Therefore, by the time the injection rate is changed, the water quality of the treated water may have already changed. This makes it very difficult to operate the system in accordance with changes in the water quality of the treated water, and in practice, there is a possibility of the injection rate being too high or too low.

[0008] Furthermore, in practice, the injection rate is determined on the safer side than the injection rate obtained by methods such as jar tests, which often leads to a tendency towards over-injection.

[0009] Furthermore, some water treatment plants do not confirm the injection rate of powdered activated carbon using jar tests, but instead inject a constant amount of powdered activated carbon into the treated water at all times. Others inject powdered activated carbon only when the water temperature rises, or increase the injection rate during periods of rising water temperature. Some water treatment plants also increase the injection rate of powdered activated carbon when they receive complaints from households that use their tap water about the odor of the tap water. In addition, some water treatment plants do not conduct jar tests, but instead check the odor of the treated water through sensory testing and regularly monitor the quality of the treated water. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2024-042997 [Overview of the project] [Problems that the invention aims to solve]

[0011] Under the above background, a method for optimizing the injection rate of powdered activated carbon according to the quality of the water to be treated is required. In a water purification plant, in order to remove each moldy odor-causing substance to the concentration standard value with a sufficient amount of powdered activated carbon, it is necessary to comprehensively consider the concentration of each substance originally dissolved in the raw water, the standard value after treatment, and the quality of the raw water, and calculate and determine an appropriate injection rate.

[0012] Conventionally, a method for calculating the injection rate of powdered activated carbon has been proposed for the purpose of reducing the concentration in raw water to the standard value for one type of odor substance to be removed.

[0013] However, in reality, it is also conceivable that two or more types of odor substances such as 2-MIB and geosmin are dissolved in a water purification plant. Although the injection rate of powdered activated carbon required for each substance can be calculated, the method and basis for setting the optimal injection rate to be finally injected are not clear at present stage. The reasons for this include, for example, the significantly different adsorption characteristics of each moldy odor substance such as 2-MIB and geosmin onto activated carbon, and the lack of sufficient knowledge about the adsorption competition phenomenon of multiple odor substances. Therefore, in the case where two or more odor substances are dissolved in the raw water, the injection amount of powdered activated carbon has to be set more excessively, prioritizing the safety of the treatment.

[0014] The embodiments of the present invention are made in view of the above circumstances, and an object is to provide a powdered activated carbon injection rate calculation device, a powdered activated carbon injection control system, a powdered activated carbon injection rate calculation method, and a computer program for setting an appropriate injection rate of powdered activated carbon for water to be treated in which two or more odor substances are dissolved.

Means for Solving the Problems

[0015] The powder activated carbon injection rate calculation device according to this embodiment includes a ratio calculation unit that calculates the ratio between the concentration equivalent value of a first odor component contained in raw water and the concentration equivalent value of a second odor component, and an injection rate calculation unit that calculates the powder activated carbon injection rate using the concentration of the odor component selected according to the result of comparing the ratio value with a threshold value. [Brief explanation of the drawing]

[0016] [Figure 1] Figure 1 is a schematic diagram showing one example configuration of a powder activated carbon injection rate calculation device and powder activated carbon injection control system according to the first embodiment. [Figure 2] Figure 2 is a flowchart illustrating an example of the operation of the powder activated carbon injection rate calculation device of the first embodiment. [Figure 3] Figure 3 is a diagram illustrating an example of the effects of a powder activated carbon injection rate calculation device, a powder activated carbon injection control system, a powder activated carbon injection rate calculation method, and a computer program according to one embodiment. [Figure 4] Figure 4 is a diagram illustrating an example of the effects of a powder activated carbon injection rate calculation device, powder activated carbon injection control system, powder activated carbon injection rate calculation method, and computer program according to one embodiment. [Figure 5] Figure 5 is a diagram illustrating an example of the effects of a powder activated carbon injection rate calculation device, a powder activated carbon injection control system, a powder activated carbon injection rate calculation method, and a computer program according to one embodiment. [Figure 6] Figure 6 is a diagram illustrating an example of the effects of a powder activated carbon injection rate calculation device, powder activated carbon injection control system, powder activated carbon injection rate calculation method, and computer program according to one embodiment. [Figure 7] Figure 7 is a schematic diagram showing one example configuration of the powder activated carbon injection rate calculation device and powder activated carbon injection control system of the second embodiment. [Figure 8] Figure 8 schematically shows the relationship between odor intensity and odor concentration, as well as an example of a calibration curve. [Figure 9]Figure 9 is a schematic diagram showing one example configuration of a powder activated carbon injection rate calculation device and powder activated carbon injection control system according to the third embodiment. [Modes for carrying out the invention]

[0017] The powder activated carbon injection rate calculation device, powder activated carbon injection control system, powder activated carbon injection rate calculation method, and computer program of the embodiment will be described below with reference to the drawings. The powder activated carbon injection calculation device and powder activated carbon injection control system of the embodiments described below include at least one processor and a memory in which a computer program executed by the processor is stored, and can be configured to realize various functions described below by software or by a combination of software and hardware.

[0018] Figure 1 is a schematic diagram showing one example configuration of a powder activated carbon injection rate calculation device and powder activated carbon injection control system according to the first embodiment. The powder activated carbon injection control system of the first embodiment includes a powder activated carbon injection rate calculation device and is applied to a water treatment plant 1 that performs water treatment including a powder activated carbon injection process.

[0019] Water treatment plant 1 comprises an intake well 21, a mixing tank 22, a flocculation tank 23, a sedimentation tank 24, a powdered activated carbon injection section 25, a rapid filtration tank 26, and a water treatment tank 27.

[0020] Raw water (water to be treated) pumped from the intake of water treatment plant 1 is guided to a sedimentation tank via a water conduit, where large impurities are removed. After this, the treated water discharged from the sedimentation tank flows through the intake well 21 into a coagulation and sedimentation tank which includes a mixing tank 22, a flocculation tank 23, and a settling tank 24.

[0021] A portion of the raw water introduced into the intake well 21 is collected and supplied to the odor information acquisition unit 2 (described later), and is also used to obtain raw water quality information. Raw water quality information may include, for example, water temperature, turbidity, color, pH, electrical conductivity, alkalinity, E260, TOC, DOC, and fluorescence intensity. Equipment for measuring the above raw water quality information is installed in the water treatment plant 1. However, the water source supplied to the odor information acquisition unit 2 (described later) and used to obtain raw water quality information does not necessarily have to be the intake well; it may be the raw water inlet or sedimentation basin at the water treatment plant 1, and for the purpose of accurately understanding water quality information, raw water before chemical injection is preferable.

[0022] A coagulant is injected into the mixing tank 22 to coagulate and settle the turbidity particles in the raw water, and the coagulant and raw water are mixed by rapid stirring. After the coagulant is injected, the water to be treated flows from the mixing tank 22 to the floc formation tank 23. In the floc formation tank 23, the incoming water to be treated is stirred by a stirrer (not shown), causing the turbidity particles to be incorporated into the flocs, and flocs of coagulated turbidity are formed. The water to be treated containing the flocs flows from the floc formation tank 23 to the sedimentation tank 24, where the flocs in the water to be treated are separated by sedimentation.

[0023] Furthermore, the treated water discharged from the sedimentation tank 24 flows into the rapid filtration tank 26. In the rapid filtration tank 26, the treated water obtained as supernatant in the sedimentation tank 24 is filtered, and fine flocs and residual coagulants that could not be separated in the coagulation sedimentation tank are removed from the treated water. In the water purification tank 27, the treated water (filtered water) discharged from the rapid filtration tank 26 is sterilized by injecting sodium hypochlorite, etc., and then stored.

[0024] The powdered activated carbon injection rate calculation device comprises an odor information acquisition unit 2 and an injection rate calculation function unit 3. The odor information acquisition unit 2 may include measuring instruments such as GC / MS and odor sensors, as well as sensory testing equipment. The odor information acquisition unit 2 can intermittently and automatically acquire the types of one or more odor components, their concentrations, and equivalent values ​​of odor intensity, using raw water sampled at the stage before chemical injection in the treatment flow of the water treatment plant 1, for example, by measurement using sensors such as GC / MS sensors and odor sensors. The odor information acquisition unit 2 supplies odor information, which associates the acquired types of odor components (identification information) with their equivalent concentration values, to the injection rate calculation function unit 3.

[0025] In the following explanation, we will describe an example where odor concentration is used as the equivalent value of the odor component concentration. However, the injection rate of powdered activated carbon can be calculated similarly even if, for example, concentration intensity is used as the equivalent value of the concentration.

[0026] The odor components in the raw water are expected to include at least one of geosmin or 2-MIB. Other possible odor substances include 2,4-heptagenal and 2,4-decagenal, which are responsible for the fishy smell, as well as ammonia, chloramines, and oily odors.

[0027] The injection rate calculation function unit 3 comprises an odor concentration ratio calculation unit 31 and an injection rate calculation unit 32. The odor concentration ratio calculation unit 31 calculates the concentration ratio R of odor substances from the odor information supplied from the odor information acquisition unit 2. For example, the odor information contains the concentration C of geosmin (first odor component). Geo and the concentration of 2-MIB (second odor component) C 2-MIB If the information contains such information, the odor concentration ratio calculation unit 31 calculates the concentration ratio R using the following formula. R=C Geo / C 2-MIB (1)

[0028] Furthermore, the odor concentration ratio calculation unit 31 can calculate the above concentration ratio R by combining multiple concentration information such as geosmin, 2-MIB, 2,4-heptagenal and 2,4-decagenal (substances that cause fishy odors), ammonia, chloramines, and oily odors, not limited to the combination of geosmin and 2-MIB.

[0029] The odor concentration ratio calculation unit 31 supplies the calculated concentration ratio R to the injection rate calculation unit 32.

[0030] The injection rate calculation unit 32 compares the concentration ratio R with a threshold value to select the concentration of the odor substance to be used in calculating the injection rate, and calculates the injection rate of powdered activated carbon required to remove the odor substance. The injection rate calculation unit 32 supplies the calculated value of the powdered activated carbon injection rate to the powdered activated carbon injection unit 25.

[0031] The injection rate calculation unit 32 may also include a support tool for calculating the injection rate of powdered activated carbon. The support tool of the injection rate calculation unit 32 is a tool that can calculate the injection rate of powdered activated carbon from the input odor substance concentration and water quality information using, for example, the calculation formula described later.

[0032] By optimizing the injection rate of powdered activated carbon using the injection rate calculation unit 32, it becomes possible to appropriately control the injection rate of powdered activated carbon. This allows for the adsorption and removal of multiple types of odor-causing substances to below standard levels, even in raw water containing a mixture of multiple types of odor-causing substances, while preventing increased costs due to the injection of excessive amounts of powdered activated carbon.

[0033] Next, an example of the operation of the powder activated carbon injection rate calculation device of this embodiment will be described. Figure 2 is a flowchart illustrating an example of the operation of the powder activated carbon injection rate calculation device of the first embodiment. First, the odor information acquisition unit 2 uses the raw water sampled at the pre-chemical injection stage (for example, the inlet where the raw water flows into the intake well 21) to obtain the types and concentrations of one or more odor components (or values corresponding to the concentration such as odor intensity) by using a GC / MS sensor or an odor sensor (step SA1). The odor information acquisition unit 2 supplies the odor information including the types and concentrations of the acquired odor components to the odor concentration ratio calculation unit 31.

[0034] The odor concentration ratio calculation unit 31 calculates the concentration ratio of the odor components contained in the raw water by using the information on the types and concentrations of the odor components included in the odor information (step SA2). Here, for example, when the odor information includes the concentration C of geosmin Geo and the concentration C of 2-MIB 2-MIB the case will be described. In this case, the odor concentration ratio calculation unit 31 calculates the concentration ratio R by the above formula (1). The odor concentration ratio calculation unit 31 supplies the calculated concentration ratio R to the injection rate calculation unit 32.

[0035] The injection rate calculation unit 32 compares the concentration ratio R with a threshold value and selects the concentration (residual rate) of the odor substance used for the calculation of the injection rate (step SA3). The threshold value used in the injection rate calculation unit 32 is set to, for example, 10. The value of this threshold changes depending on the raw water quality, particularly the concentration of each odor substance in the raw water.

[0036] The injection rate calculation unit 32 compares the concentration ratio R with the threshold value of 10. When the concentration ratio R is less than 10 (step SA3, YES), it uses the concentration C of 2-MIB 2-MIB (the residual rate C of 2-MIB 2-MIB_Target / C 2-MIB ) to calculate the powdered activated carbon injection rate I car by the following formula (2) (step SA4). I car =f(C 2-MIB_Target / C 2-MIB ) (2)

[0037] In the above formula (2), C 2-MIB_Target is the value of the management target concentration of 2-MIB. The above powdered activated carbon injection rate Icar When determining this by the concentration of 2-MIB, the 2-MIB concentration in the raw water is C 2-MIB and the target value (reference value) of 2-MIB concentration after treatment C 2-MIB_Target Since the ratio, i.e., the target 2-MIB residue rate after treatment, is used, if the water treatment plant in question has its own set post-treatment standard value (management target concentration value), that value must be entered.

[0038] The injection rate calculation unit 32 compares the concentration ratio R with the threshold value 10, and if the concentration ratio R is 10 or greater (step SA3, NO), the concentration C of geosmin is calculated. Geo (Geosmin survival rate C) Geo_Target / C Geo Using ), the powder activated carbon injection rate I is calculated using the following formula (3). car Calculate (Step SA5). I car =f(C Geo_Target / C Geo ) (3)

[0039] Note that in equation (3) above, C Geo_Target This is the target concentration value for geosmin. The above powdered activated carbon injection rate I car When determining this by the concentration of geosmin, the geosmin concentration C in the raw water is used. Geo And the target value (reference value) of geosmin concentration after treatment C Geo_Target Since the ratio, i.e., the target geosmin retention rate after treatment, is used, if the water treatment plant in question has its own set post-treatment standard value (management target concentration value), that value must be entered.

[0040] Specifically, the injection rate calculation unit 32 first compares the concentration ratio R with the threshold 10 to select the type of odor substance to be adsorbed, and then determines a relationship curve between the powdered activated carbon injection rate and the odor substance retention rate according to the selected type of odor substance and the raw water quality. Note that the relationship curve between the powdered activated carbon injection rate and the odor substance retention rate constantly changes with fluctuations in the raw water quality. Next, the injection rate calculation unit 32 compares the odor substance concentration C in the raw water with the target odor concentration (management target concentration) C Target From the target survival rate (CTarget By calculating / C) and referring to the relationship curve between the powdered activated carbon injection rate and the odor substance retention rate, an appropriate injection rate for powdered activated carbon (one that can achieve the target retention rate) can be determined.

[0041] The injection rate calculation unit 32 can use a known calculation formula as the injection rate calculation formula. The injection rate calculation unit 32 uses, for example, the following equation (2), which is a modified version of the Freundlich adsorption isotherm equation (1), to determine the powdered activated carbon injection rate I required for the adsorption and removal of odorous substances. car It can perform calculations.

[0042] W = K × C N (1) W: Unit adsorption amount of odor substances [ng / mg] C: Concentration of odor-causing substances in treated water [ng / L] K, N: Adsorption coefficient of odor substances

[0043]

number

[0044] The Freundlich adsorption isotherm has been shown to match the adsorption characteristics of the target substance in powder activated carbon adsorption tests with very high accuracy. Therefore, if the estimated value of the Freundlich adsorption coefficient in the Freundlich adsorption isotherm can be accurately calculated, the accuracy of calculating the powder activated carbon injection rate required to achieve the target concentration of the target substance will also be improved.

[0045] The injection rate calculation unit 32 can calculate the optimal injection rate of powdered activated carbon at a water treatment plant based on the Freundlich adsorption isotherm by using, for example, estimation formulas for adsorption coefficients K and N constructed based on multiple water quality parameters.

[0046] The adsorption coefficient K can be calculated using an estimation formula that includes, for example, a term combining multiple indicators such as E260 (ultraviolet absorbance at a wavelength of 260 nm), which is an index representing the organic matter concentration of raw water, dissolved organic carbon (DOC), total organic carbon (TOC), and fluorescence intensity (FL, relative fluorescence intensity at a wavelength of 425 nm emitted in response to excitation light at a wavelength of 345 nm), and a term that is one or more of the following: E260, DOC, TOC, FL, pH, water temperature, alkalinity, and turbidity. The adsorption coefficient N can be calculated using an estimation formula that utilizes the adsorption coefficient K.

[0047] The measured values ​​such as water quality indicators and chemical injection conditions used in the above calculation formula and the adsorption coefficient estimation formula may be values ​​continuously measured by online sensors installed at water treatment plant 1. If there are items in the water quality indicators and chemical injection conditions used in the injection rate calculation formula that cannot be obtained by online sensors, manual analysis data performed at water treatment plant 1 may be input or used to estimate. Examples include TOC and DOC. If the injection rate calculation formula includes injection rate information other than powdered activated carbon, online data of the injection rate information of coagulants and sodium hypochlorite injected in the treatment flow of water treatment plant 1 may be used.

[0048] The injection rate calculation unit 32 calculates the injection rate I of the powdered activated carbon. car The value of is supplied to the powder activated carbon injection unit 25 (step SA6). The powder activated carbon injection unit 25 injects the value of I based on the flow rate information of the treatment flow of the water treatment plant 1. car Convert this into an injection volume, and inject the powdered activated carbon into the water to be treated, either as a slurry or in powder form.

[0049] Figures 3 to 6 illustrate an example of the effects of a powder activated carbon injection rate calculation device, powder activated carbon injection control system, powder activated carbon injection rate calculation method, and computer program according to one embodiment.

[0050] This section describes an example of the concentrations of 2-MIB and geosmin when the injection rate of powdered activated carbon is changed, using two types of raw water with different concentration ratios R of 2-MIB and geosmin. The water quality standard for 2-MIB and geosmin is 10 ng / L, and the management target values ​​set by water treatment plant 1 vary depending on the water treatment plant 1, but here we assume they are 2 to 5 ng / L.

[0051] Figures 3 and 4 show an example of the concentration when powdered activated carbon is injected into raw water with a concentration ratio R of 1, where the concentration of 2-MIB is 100 ng / L and the concentration of geosmin is 100 ng / L. In this case, the injection rate of powdered activated carbon required to reduce the 2-MIB concentration to the target level is sufficient to adequately achieve the target level for geosmin concentration.

[0052] Figures 5 and 6 show an example of the concentrations obtained when powdered activated carbon is injected into raw water with a concentration ratio R of 10, where the concentration of 2-MIB is 10 ng / L and the concentration of geosmin is 100 ng / L. In this case, it can be seen that the injection rate of powdered activated carbon used to reduce the concentration of 2-MIB to the target value does not allow the concentration of geosmin to reach the target value. In such cases, by setting the injection rate of powdered activated carbon so that the concentration of geosmin reaches the target value, both the concentration of 2-MIB and the concentration of geosmin can be reduced to the target value.

[0053] As described above, by selecting odor concentration information to be used when calculating the injection rate of powdered activated carbon based on the results of comparing the concentration ratio of odorous substances contained in the raw water with a threshold, it is possible to appropriately set the injection rate of powdered activated carbon for raw water containing multiple odorous substances.

[0054] Furthermore, the threshold concentration ratio R used to select the type of odor substance for injection rate calculation will vary depending on the brand of powdered activated carbon used at the water treatment plant where the system will be installed, the reaction time of the powdered activated carbon, and the quality of the raw water. Therefore, it is desirable to confirm and set the threshold concentration ratio by conducting an adsorption test using the raw water and activated carbon of the water treatment plant in question before installation.

[0055] According to this embodiment, even in raw water containing two or more types of moldy odor substances, by selecting odor substance information to be used in calculating the powdered activated carbon injection rate according to the concentration ratio of the odor substances, an appropriate powdered activated carbon injection rate can be set, and all of the multiple types of odor substances, including 2-MIB and geosmin, can be sufficiently removed to the standard concentration (or the concentration control target value).

[0056] Specifically, when the concentrations of 2-MIB and geosmin in the raw water are obtained, if the geosmin concentration is less than a certain multiple of the 2-MIB concentration, a calculation formula using the 2-MIB concentration is used to calculate the injection rate. If the geosmin concentration is a certain multiple or greater than the 2-MIB concentration, a calculation formula using the geosmin concentration is used to calculate the injection rate. As described above, by selecting the concentration information of the odor substances used to calculate the injection rate of powdered activated carbon according to the concentration ratio of the two types of odor substances, and by switching the calculation formula used to calculate the injection rate, it is possible to remove all odor substances to below the standard value (or management target value) without injecting more powdered activated carbon than necessary.

[0057] In other words, according to this embodiment, it is possible to provide a powder activated carbon injection rate calculation device, a powder activated carbon injection control system, a powder activated carbon injection rate calculation method, and a computer program for setting an appropriate injection rate of powder activated carbon for water to be treated in which two or more odor-causing substances are dissolved.

[0058] Next, the powder activated carbon injection rate calculation device, powder activated carbon injection control system, powder activated carbon injection rate calculation method, and computer program of the second embodiment will be described in detail with reference to the drawings. In the following description, components similar to those in the first embodiment described above will be denoted by the same reference numerals and their descriptions will be omitted.

[0059] Figure 7 is a schematic diagram showing one example configuration of the powder activated carbon injection rate calculation device and powder activated carbon injection control system of the second embodiment. The powder activated carbon injection control system of this embodiment comprises a powder activated carbon injection rate calculation device and an administrator terminal 4. The powder activated carbon injection rate calculation device comprises an odor information acquisition unit 2 and an injection rate calculation function unit 3.

[0060] This embodiment describes a case where odor substance concentration information cannot be obtained by automatic measurement. In this case, the odor information acquisition unit 2 acquires odor information based, for example, on manually entered data of measurements from a GC / MS or odor sensor, or on manually analyzed data of odor concentration obtained through sensory testing.

[0061] Figure 8 schematically shows the relationship between odor intensity and odor concentration, as well as an example of a calibration curve. One example of a method for calculating odor concentration from odor intensity obtained through sensory testing is to estimate the odor concentration using a calibration curve. When calculating odor concentration using a calibration curve, it is desirable that the odor information acquisition unit 2, for example, treats all odor intensities as 2-MIB concentrations and calculates the odor concentration (odor information based on odor intensity values) by referring to a calibration curve set to be on the safe side.

[0062] Odor information, including the type and concentration of odor components, acquired by the odor information acquisition unit 2, can be supplied to the injection rate calculation function unit 3 by manual input. The frequency at which odor information is manually input to the injection rate calculation function unit 3 is expected to be, for example, about once or twice a day. The odor information acquisition unit 2 may also use a numerical value (equivalent to the concentration value) corresponding to the odor intensity and the type of odor component as odor information.

[0063] The injection rate calculation function unit 3 comprises an odor concentration ratio calculation unit 31 and an injection rate calculation unit 32. In the injection rate calculation function unit 3, the functions of the odor concentration ratio calculation unit 31 and the injection rate calculation unit 32 are the same as in the first embodiment described above, but it differs from the first embodiment in that the injection rate calculated by the injection rate calculation unit 32 is output to the administrator terminal 4.

[0064] The administrator terminal 4 is a terminal device that can be operated by the administrator (operator) of the water treatment plant 1, and can be configured to communicate with the injection rate calculation function unit 3 and the powdered activated carbon injection unit 25. The administrator terminal 4 is, for example, a personal computer, smartphone, tablet terminal, etc., and includes a display unit that displays the value of the injection rate supplied from the injection rate calculation unit 32, an operation unit that allows the administrator to input the value of the injection rate by operating it, and an injection rate output unit that outputs the value of the injection rate input by the administrator (operator) to the powdered activated carbon injection unit 25.

[0065] The manager of water treatment plant 1 can determine the actual injection rate by referring to the value of the powdered activated carbon injection rate calculated by the injection rate calculation unit 32, and then operate the manager terminal 4 to supply an appropriate powdered activated carbon injection rate to the powdered activated carbon injection unit 25.

[0066] The powdered activated carbon injection unit 25 converts the powdered activated carbon injection rate supplied from the administrator terminal 4 into an injection volume based on the flow rate information of the treatment flow of the water treatment plant 1, and injects the powdered activated carbon into the water to be treated, either as a slurry or in powder form.

[0067] According to the second embodiment described above, similar to the first embodiment described above, it is possible to provide a powder activated carbon injection rate calculation device, a powder activated carbon injection control system, a powder activated carbon injection rate calculation method, and a computer program for setting an appropriate powder activated carbon injection rate for water to be treated in which two or more odor substances are dissolved.

[0068] Furthermore, the powder activated carbon injection rate calculation device, powder activated carbon injection control system, powder activated carbon injection rate calculation method, and computer program of this embodiment can assist managers in determining the powder activated carbon injection rate.

[0069] Next, the powder activated carbon injection rate calculation device, powder activated carbon injection control system, powder activated carbon injection rate calculation method, and computer program of the third embodiment will be described in detail with reference to the drawings. In this embodiment, we will describe a case where it is not possible to identify the type of odorous substance contained in the raw water.

[0070] Odor sensors, for example, use a metallic-organic frame (MOF) adsorbent coated on a sensor with a quartz crystal oscillator. This adsorbent adsorbs specific odor species from the volatile gases of the raw water containing dissolved odor substances, and the odor concentration in the water is estimated by the change in the quartz crystal oscillator's vibration frequency due to the change in the weight of the adsorbent. However, the adsorbent may also adsorb coexisting odor components. Therefore, depending on the sensor's performance, it may adsorb coexisting odors sufficiently, making it difficult to determine the concentration of individual odor types.

[0071] Furthermore, in sensory testing, it is extremely difficult to distinguish the intensity of odors by type, and there is also a masking effect between odors, so it is conceivable that estimating the concentration of each type of odor substance may be difficult.

[0072] In the cases described above, the powder activated carbon injection rate calculation device and powder activated carbon injection control system of this embodiment consider the odor intensity values ​​obtained from the odor sensor or the odor intensity values ​​confirmed by the sensor test as values ​​derived from one predetermined type of odor. For example, a typical case is to calculate the powder activated carbon injection rate by considering the odor sensor values ​​or odor intensity values ​​obtained from the sensor test as originating from 2-MIB.

[0073] Figure 9 is a schematic diagram showing one example configuration of a powder activated carbon injection rate calculation device and powder activated carbon injection control system according to the third embodiment. In the powder activated carbon injection rate calculation device of this embodiment, the odor information acquisition unit 2 may include an odor sensor and a sensory testing device. The odor information acquisition unit 2 acquires the odor intensity values ​​obtained from the odor sensor or sensory testing, substitutes them into a calibration curve for 2-MIB concentration calculation that has been prepared in advance, and calculates the 2-MIB concentration. The odor information acquisition unit 2 supplies the calculated 2-MIB concentration to the injection rate calculation function unit 3. The 2-MIB concentration (odor concentration information) calculated by the odor information acquisition unit 2 may be supplied to the injection rate calculation function unit 3 by manual input, or it may be input intermittently and automatically.

[0074] The injection rate calculation unit 3 includes an injection rate calculation unit 32. When odor concentration information obtained from odor sensors or sensory tests is manually entered into the injection rate calculation unit 3, the frequency of input of odor concentration information is expected to be approximately 1 to 2 times per day.

[0075] The injection rate calculation unit 32 of the injection rate calculation function unit 3 uses the 2-MIB concentration calculated by the odor information acquisition unit 2 to determine the powder activated carbon injection rate I using the above formula (2). car The injection rate calculation unit 32 inputs the necessary information if the injection rate calculation formula includes water quality information or injection rate information other than powdered activated carbon. The injection rate calculation unit 32 supplies the calculated powder activated carbon injection rate to the powder activated carbon injection unit 25.

[0076] The powdered activated carbon injection unit 25 converts the powdered activated carbon injection rate supplied from the administrator terminal 4 into an injection volume based on the flow rate information of the treatment flow of the water treatment plant 1, and injects the powdered activated carbon into the water to be treated, either as a slurry or in powder form.

[0077] Here, we will explain the advantages of considering all odor sensor readings and odor intensity values ​​obtained through sensory testing as originating from 2-MIB in the odor information acquisition unit 2. In conventional powdered activated carbon, 2-MIB is less adsorbed and removed than geosmin. Furthermore, raw water contains various odors in addition to those originating from 2-MIB. Therefore, if all odors are attributed to 2-MIB, the actual concentration of 2-MIB is likely to be overestimated. Consequently, if odor sensor readings and odor intensities are all attributed to 2-MIB, the injection rate of powdered activated carbon required to remove all 2-MIB can be estimated higher, thus ensuring effective treatment.

[0078] However, some activated carbons are particularly adsorbent of 2-MIB depending on their pore size distribution, specific surface area, and material. When using such powdered activated carbon, it is an exception, so when applying this embodiment to a water treatment plant, it is desirable to change the procedure for estimating odor concentration using sensor readings and odor intensity values ​​according to the function and adsorption characteristics of the powdered activated carbon used in that water treatment plant.

[0079] According to the third embodiment described above, similar to the first embodiment described above, it is possible to provide a powder activated carbon injection rate calculation device, a powder activated carbon injection control system, a powder activated carbon injection rate calculation method, and a computer program for setting an appropriate powder activated carbon injection rate for water to be treated in which two or more odor substances are dissolved.

[0080] In addition, in the above-described embodiments, the odor information acquisition unit 2 may acquire intermittent automatic measurement results of moldy odor concentration using GC / MS or an odor sensor for raw water containing two types of odor substances such as moldy odor substances, or it may acquire information on the type and concentration of odor substances from manual measurement results or sensory test results by water treatment plant workers (managers).

[0081] Furthermore, the configurations of the above-described multiple embodiments may be combined. For example, the powder activated carbon injection control systems of the first and third embodiments described above may include the administrator terminal 4 of the second embodiment.

[0082] The program according to this embodiment may be transferred while stored on an electronic device, or it may be transferred while not stored on an electronic device. In the latter case, the program may be transferred via a network, or it may be transferred while stored on a storage medium. The storage medium is a non-temporary tangible medium. The storage medium is a computer-readable medium. The storage medium can be any medium that is capable of storing a program and is readable by a computer, such as a CD-ROM or memory card, and its form is not limited.

[0083] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0084] 1...Water treatment plant, 2...Odor information acquisition unit, 3...Injection rate calculation function unit, 4...Administrator terminal, 25...Powdered activated carbon injection unit, 31...Odor concentration ratio calculation unit (ratio calculation unit), 32...Injection rate calculation unit

Claims

1. A ratio calculation unit that calculates the ratio between the concentration equivalent value of the first odor component contained in the raw water and the concentration equivalent value of the second odor component, A powder activated carbon injection rate calculation device comprising: an injection rate calculation unit that calculates the injection rate of powder activated carbon using the concentration of an odor component selected according to the result of comparing the ratio value with a threshold value.

2. The powder activated carbon injection rate calculation device according to claim 1, wherein the first odor component is 2-MIB and the second odor component is geosmin.

3. The powder activated carbon injection rate calculation device according to claim 1, further comprising an odor information acquisition unit that acquires the equivalent concentration values ​​of a first odor component and a second odor component in the raw water, associates the odor type with the equivalent concentration values, and supplies them to the ratio calculation unit.

4. The powder activated carbon injection rate calculation device according to claim 3, wherein the odor information acquisition unit includes at least one measuring instrument, such as a GC / MS or an odor sensor, for measuring the concentration of odor components contained in the raw water.

5. The powder activated carbon injection rate calculation device according to claim 3, wherein the odor information acquisition unit includes a sensory testing device and acquires odor information based on the odor intensity value obtained by the sensory testing.

6. A powder activated carbon injection rate calculation device according to any one of claims 1 to 5, A powder activated carbon injection control system comprising: a powder activated carbon injection unit that injects powder activated carbon into water to be treated according to the injection rate of powder activated carbon calculated by the injection rate calculation unit.

7. A powder activated carbon injection rate calculation device according to any one of claims 1 to 5, A powder activated carbon injection unit that injects powder activated carbon into the water to be treated according to the injection rate value, A display unit that shows the injection rate of the powdered activated carbon calculated by the injection rate calculation unit, A powder activated carbon injection control system comprising: an injection rate output unit that supplies an injection rate value input by an operator to the powder activated carbon injection unit.

8. The ratio of the equivalent concentration value of the first odor component contained in the raw water to the equivalent concentration value of the second odor component is calculated. A method for calculating the injection rate of powdered activated carbon, which involves calculating the injection rate of powdered activated carbon using the concentration of an odor component selected according to the result of comparing the ratio value with a threshold value.

9. A computer program that causes a computer to execute the powder activated carbon injection rate calculation method described in claim 8.

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