JP2022026969A - Water treatment system and water treatment method - Google Patents

Abstract

To provide a water treatment system and a water treatment method capable of optimizing the injection rate of powdered activated carbon.MEANS FOR SOLVING THE PROBLEM: A water treatment system is equipped with a first coagulant injection rate calculation unit and an activated carbon injection rate calculation unit. The first flocculant injection rate calculation unit calculates, based on the quality of the raw water, the first flocculant injection rate, which is the injection rate of flocculant required for flocculation and sedimentation of suspended matter in the raw water. The activated carbon injection rate calculation unit calculates the first powdered activated carbon injection rate, which is the injection rate of powdered activated carbon required to remove odorous substances from raw water, based on: the concentration of odorous substances contained in raw water; at least one of UV absorbance, fluorescence intensity and soluble organic carbon concentration of raw water; and the first flocculant injection rate.SELECTED DRAWING: Figure 1

Description

An embodiment of the present invention relates to a water treatment system and a water treatment method for injecting powdered activated carbon and a flocculant into water to be treated to remove odorous substances, soluble organic substances and turbid substances in the water to be treated.

Generally, the treated water (hereinafter, also referred to as "raw water") taken from rivers, lakes, marshes, reservoirs, etc. includes soluble natural organic substances such as odorous substances and fumin (hereinafter, also referred to as "soluble organic substances"). It contains turbid substances such as fine particles.

On the other hand, in water purification plants, chemical agents such as sodium hypochlorite are injected for the purpose of removing and disinfecting metals such as iron and manganese, but in the case of raw water containing soluble organic substances, it is regarded as soluble organic substances. Chemicals chemically react to produce trihalomethanes and haloacetic acids (hereinafter also referred to as "disinfection by-products"). Since these disinfection by-products are carcinogens, their production needs to be suppressed.

Many waterworks inject powdered activated carbon to remove odorous substances and soluble organic matter in raw water, and inject a flocculant to remove turbidity. In this type of water treatment system, it is necessary to determine the injection rate of powdered activated carbon according to the quality of the raw water.

As a method for determining the injection rate of powdered activated carbon, a jar test (hereinafter, also referred to as "beaker test") is often used. The jar test is to collect raw water into multiple beakers, inject different amounts of powdered activated charcoal into each of the collected raw water, evaluate the removal rate of odorous substances and soluble organic substances, and evaluate the odor after treatment. This is a method for obtaining the minimum powdered activated carbon injection rate required to reduce the concentration and soluble organic substance below the target concentration.

However, in the above method of determining the injection rate of the powdered activated carbon by the jar test, it is very difficult to inject the powdered activated carbon in accordance with the change in the water quality of the raw water, and there is a possibility that the injection rate may be excessive or insufficient. In addition, since it takes time to obtain the optimum injection rate of the powdered activated carbon in the jar test, it is possible that the water quality of the raw water has already changed when the optimum injection rate of the powdered activated carbon is obtained.

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

Further, 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.

The unit price of powdered activated carbon is much higher than that of 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, and from an economic point of view, excessive injection of powdered activated carbon is suppressed, and the optimum injection rate of powdered activated carbon according to changes in the quality of raw water. A method of controlling the above is desired.

As a method of controlling the powdered activated carbon injection rate, for example, in the raw water in the powdered activated carbon treatment tank, the odorous substance in the atmosphere near the water surface is detected by the odor sensor, and the raw water is based on the odor intensity indicated value obtained from the odor substance. There is a method of calculating the powdered activated carbon injection rate with respect to the flow rate of the above and controlling the powdered activated carbon based on the powdered activated carbon injection rate (see, for example, Patent Document 1).

As another method, the state of the pulverized coal in the raw water after the injection of the activated carbon powder is observed, and the observation result is used as a feedback signal to send the injection rate of the activated carbon in the previous stage to the calculation unit to set the target. There is a control method for controlling the injection rate of the powdered activated carbon so that the runoff turbidity is obtained (see, for example, Patent Document 2).

However, such a conventional method does not consider the water quality of raw water, and its accuracy is insufficient in optimizing the injection rate of powdered activated carbon. In particular, the influence of coexisting soluble organic substances on the adsorption characteristics of odorous substances is not taken into consideration.

To this end, there is a method of obtaining the coefficients that affect the residual rate of the odorous substance and the organic substance at the time of injecting the powdered activated carbon, and obtaining the required powdered activated carbon injection rate (see, for example, Patent Document 3).

However, when injecting powdered activated carbon, it is necessary to remove the powdered activated carbon that has adsorbed the target substance by coagulation sedimentation and turbidity operation by the filtration step in the subsequent stage.

In this case, the odorous substance and the soluble organic substance which are the adsorption targets of the powdered activated carbon are also removed in the coagulation treatment step, but since they are not considered in the conventional powdered activated carbon injection control, the powdered activated carbon is excessive in most cases. The result is that it is injected into. As a result, not only the chemical cost becomes excessive, but also the excessive injection of powdered activated carbon causes an increase in cost due to an increase in the coagulant injection rate required for its removal, and an increase in processing cost due to an increase in the amount of mud discharged. ..

Japanese Unexamined Patent Publication No. 2-284678 Japanese Patent No. 2969927 Japanese Patent No. 4153893

An object to be solved by the present invention is to provide a water treatment system and a water treatment method capable of optimizing the injection rate of powdered activated carbon.

The water treatment system of the embodiment includes a first coagulant injection rate calculation unit and an activated carbon injection rate calculation unit. The first coagulant injection rate calculation unit calculates the first coagulant injection rate, which is the injection rate of the coagulant required for coagulation and precipitation of the turbidity of the raw water, based on the water quality of the raw water. The activated carbon injection rate calculation unit is based on the concentration of the odorous substance in the raw water, at least one of the ultraviolet absorbance, the fluorescence intensity, and the soluble organic carbon concentration of the raw water, and the injection rate of the first flocculant. The first powdered activated carbon injection rate, which is the injection rate of powdered activated carbon required for removing odorous substances in water, is calculated.

It is a conceptual diagram which shows the example which applied the water treatment system to which the water treatment method common to each embodiment of this invention is applied to the water treatment facility of the rapid filtration system. It is a block diagram which shows the structural example of the activated carbon injection rate calculation part in the water treatment system of 1st Embodiment. It is a figure which shows the flow of the treatment by the water treatment system to which the water treatment method of 1st Embodiment is applied. It is a figure which shows an example of the relationship between the coagulant injection rate I _pall by the coagulation treatment, and the ultraviolet absorbance residual rate RUV _pall . It is a figure which shows the relationship between the aggregating agent injection rate I _pack , and the combined treatment coefficient F _DOM . It is a figure which shows the relationship between the specific absorbance SUVA of raw water, and a coefficient f. It is a figure which shows the relationship between the powdered activated carbon injection rate I _car and the odor substance concentration residual rate RC _car after powdered activated carbon treatment. It is a figure which shows the relationship between the flocculant injection rate I pack and the odor substance concentration residual rate RC _{car / packl in} the combined treatment of powdered activated carbon and a flocculant. It is a block diagram which shows the structural example of the coagulant injection rate calculation part in the water treatment system of 2nd Embodiment. It is a figure which shows the flow of the treatment by the water treatment system to which the water treatment method of 2nd Embodiment is applied.

Hereinafter, the water treatment system and the water treatment method according to each embodiment of the present invention will be described with reference to the drawings.

(Constitution)
First, a configuration of a water treatment system to which a water treatment method is applied, which is common to each embodiment of the present invention, will be described.

FIG. 1 is a conceptual diagram showing an example in which a water treatment system to which a water treatment method is applied, which is common to each embodiment of the present invention, is applied to a water treatment facility of a rapid filtration method.

The water treatment system of each embodiment of the present invention is not limited to the water treatment facility of the rapid filtration method, but also to the water treatment facilities of other methods such as the water treatment facility of the membrane filtration method and the sand filtration method. Applicable.

As shown in FIG. 1, the water treatment system 1 is incorporated in the water treatment facility 3 together with the water treatment device 2.

The water treatment device 2 performs an adsorption treatment and a coagulation sedimentation on the raw water A. The adsorption treatment is a treatment for adsorbing and removing odorous substances and soluble organic substances in the raw water A with powdered activated carbon. The coagulation sedimentation is a treatment for coagulating and sedimenting the turbidity in the raw water A with a coagulant.

The water treatment device 2 includes a landing well 20, a powdered activated carbon injection device 21, a coagulant mixing pond 30, a coagulant injection device 31, a floc forming pond 40, a settling pond 50, a filtration pond 60, and a water purification pond 70.

The landing well 20 stores raw water A, which is the water to be treated by the water treatment facility 3. The landing well 20 is connected to the coagulant mixing pond 30 by a pipe 91, and the raw water A is guided from the landing well 20 to the coagulant mixing pond 30 via the pipe 91. In the pipe 91 in front of the landing well 20, a water quality instrument set 10 for measuring the water quality of the raw water A, an odor sensor 11 for measuring the odorous substance concentration in the raw water A, and a soluble organic for measuring the organic substance concentration index in the raw water A A material index meter set 12 and a flow meter 13 for measuring the flow rate of raw water A are provided.

The water quality meter set 10 includes, but is not limited to, a turbidity meter 10a, an alkalinity meter 10b, a water temperature meter 10c, and a pH meter 10d, and these sensors measure various water qualities and then treat the measurement data with water. Send to system 1.

The Soluble Organic Index Meter Set 12 includes, but is not limited to, an ultraviolet absorbance meter 12a, a fluorescence intensity meter 12b, and a soluble organic carbon concentration (DOC) meter 12c, which sensors water-treat the measurement data. Send to system 1.

The powdered activated carbon C is injected into the water landing well 20 from the powdered activated carbon injection device 21 for the adsorption treatment of the odorous substance and the soluble organic substance in the raw water A.

The powdered activated carbon C is stored in the powdered activated carbon injection device 21. The powdered activated carbon injection device 21 injects the powdered activated carbon C into the raw water A landing on the water landing well 20 based on the control from the water treatment system 1.

In the coagulant mixing pond 30, suspended solids (turbidity) such as clay, bacteria, and algae contained in the raw water A and powdered activated carbon C injected in the landing well 20 are coagulated from the coagulant injection device 31. It is aggregated by the agent P to produce fine flocs. The flocculant mixing pond 30 is equipped with a stirrer 32 such as a flash mixer.

The pH measuring device 14 is provided in the coagulant mixing pond 30. The pH measuring device 14 measures the pH of the mixed water B in which the flocculant P is injected into the raw water A, and transmits the measured data to the water treatment system 1.

The flocculant P is stored in the flocculant injection device 31. Further, the coagulant injection device 31 is connected to the water treatment system 1 and injects the coagulant P into the coagulant water B of the coagulant admixture pond 30 based on the control by the water treatment system 1.

As the coagulant P, it is preferable to use an aluminum-based coagulant and an iron-based coagulant. Examples of the aluminum-based flocculant include aluminum sulfate (aluminum sulfate band) and polyaluminum chloride (PACl). Examples of iron-based flocculants include iron chloride, iron sulfate, and polysilica iron.

In the floc forming pond 40, the size of fine flocs contained in the admixture water B supplied from the coagulant admixture pond 30 grows. In the example shown in FIG. 1, the floc forming pond 40 has, for example, two stirring ponds 40a and 40b, but the number of stirring ponds is not limited to two.

The settling pond 50 is provided downstream of the floc forming pond 40, and in the settling pond 50, the settling separation of the flocs grown in the floc forming pond 40 is performed. Flock-mixed water stays in the settling pond 50 for a predetermined time or longer. As a result, the flocs in the floc-mixed water settle and settle in the lower part of the settling pond 50. The flocs settled in the settling pond 50 are discharged as sludge from the bottom of the settling pond 50 and treated.

The filtration pond 60 is provided downstream of the settling pond 50. The supernatant water Z obtained by staying in the settling pond 50 for a predetermined time or longer is supplied to the filtration pond 60. The supernatant water Z supplied to the filter pond 60 passes through the filter layer 60a formed in the filter pond 60, so that minute flocs that have not been settled and removed in the settling pond 50 are removed. The filtered water W from which the minute flocs have been removed is sent to the water purification pond 70 as clean water.

The landing well 20 and the coagulant mixing pond 30 are provided with an oxidizing agent injection device 23 for injecting sulfuric acid or the like used as a chemical for adjusting the pH of the raw water A and the mixing water B, and disinfection of algae and bacteria. An injection device 22 for injecting sodium hypochlorite or the like is connected.

Similarly, the filter pond 60 is also connected to an alkaline agent injection device 61 for injecting caustic soda 72 or the like used as an agent for adjusting the pH of the supernatant liquid Z.

The water purification pond 70 also has an alkaline agent injection device 72 for injecting caustic soda used as a chemical for adjusting the pH of clean water W, algae, sodium hypochlorite for disinfecting bacteria, and the like. An injection device 71 for injection is connected.

The pipe 92 for discharging the filtered water from the filter pond 60 is provided with a filtered water ultraviolet transmittance meter 15 for measuring the ultraviolet absorbance of the filtered water W.

The water purification pond 70 is provided with a tap water quality meter set 80, and the tap water quality meter set 80 has turbidity / color, residual salt concentration, pH, and water temperature as the water quality of the filtered water W discharged as tap water. It includes a turbidity / chromaticity sensor 80a, a residual salt concentration sensor 80b, a pH sensor 80c, a water temperature sensor 80d, and the like for measuring and the like.

(First Embodiment)
Next, a water treatment system to which the water treatment method of the first embodiment of the present invention is applied will be described.

As shown in FIG. 1, the water treatment system 1 includes an adsorption treatment for removing odorous substances and soluble organic substances in raw water A with powdered activated carbon, and a coagulation sedimentation treatment for coagulating and precipitating turbid substances in raw water A with a coagulant. It is applied to the water treatment facility 3 including the water treatment apparatus 2 which sequentially performs the above, and has a treated water quality target setting unit 100, an activated carbon injection rate calculation unit 200, and a coagulant injection rate calculation unit 300 as components.

The activated carbon injection rate calculation unit 200 and the flocculant injection rate calculation unit 300 record a program that realizes these functions on a computer-readable recording medium, and cause the computer system to read the program recorded on the recording medium. It will be realized by that.

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

Such a coagulant injection rate calculation unit 300 receives measurement data from the water quality meter set 10 and the pH measuring device 14, and uses the received measurement data to coagulate and precipitate based on the water quality of the raw water A before the adsorption treatment. The flocculant injection rate I _pacl , which is the injection rate of the flocculant P to be injected into the raw water A in the treatment, is calculated. Then, the calculated result of the coagulant injection rate I _pack is output to the activated carbon injection rate calculation unit 200 and the coagulant injection device 31.

On the other hand, the activated carbon injection rate calculation unit 200 obtains the setting data from the treated water quality target setting unit 100, the measurement data from the odor sensor 11, the soluble organic matter index meter set 12, and the calculation result from the coagulant injection rate calculation unit 300. Using these received and received data, the odorous substance concentration _{CR in the raw water A before the adsorption treatment, the ultraviolet absorbance UV R, the fluorescence intensity FL R , and} the soluble organic carbon concentration of the raw water A before the adsorption treatment. Based on at least one of the DOC _R and the coagulant injection rate I _pack , the powdered activated carbon injection rate I _car , which is the injection rate of the powdered activated carbon C to be injected into the raw water A for the adsorption treatment, is calculated, and the powdered activated carbon is injected. Output to device 21.

For this purpose, the activated carbon injection rate calculation unit 200 has a configuration as illustrated in FIG.

FIG. 2 is a block diagram showing a configuration example of an activated carbon injection rate calculation unit in the water treatment system of the first embodiment.

The activated carbon injection rate calculation unit 200 includes a data reception unit 200a, a data processing unit 200b, an organic substance-compatible activated carbon injection rate calculation unit 203, an odorous substance concentration residual rate estimation unit 204 after combined treatment, an odor-compatible activated carbon injection rate calculation unit 207, and activated carbon. It has an injection rate determining unit 209.

The data receiving unit 200a includes measurement data from the odor sensor 11, the soluble organic matter index meter set 12, and setting data set by the treated water quality target setting unit 100 (for example, target odor intensity, target soluble organic body carbon concentration, ultraviolet rays). Absorbance, etc.) and the calculation result (aggregating agent injection rate I _pack ) from the coagulant injection rate calculation unit 300 are received.

The data processing unit 200b receives and stores these data received by the data receiving unit 200a from the data receiving unit 200a, performs data processing such as necessary operations using the stored data, and stores the result as well. .. The data stored in the data processing unit 200b in this way includes the organic substance-compatible activated carbon injection rate calculation unit 203, the odorous substance concentration residual rate estimation unit 204 after the combined treatment, the odor-compatible activated carbon injection rate calculation unit 207, and the activated carbon injection rate determination. It can be used by the unit 209.

Further, the result calculated by the organic substance-compatible activated carbon injection rate calculation unit 203, the odor substance concentration residual rate estimation unit 204 after the combined treatment, and the odor-compatible activated carbon injection rate calculation unit 207 is also sent to the data processing unit 200b. As a result, the results calculated by the organic substance-compatible activated carbon injection rate calculation unit 203, the odor substance concentration residual rate estimation unit 204 after the combined treatment, and the odor-compatible activated carbon injection rate calculation unit 207 are combined with the organic substance-compatible activated carbon injection rate calculation unit 203. It is shared by the odor substance concentration residual rate estimation unit 204 after treatment, the odor-responsive activated carbon injection rate calculation unit 207, and the activated carbon injection rate determination unit 209.

The odorant concentration residual rate estimation unit 204 after the combined treatment uses the data stored in the data processing unit 200b to continuously perform the powdered activated carbon treatment and the agglomeration treatment. The odorous substance concentration residual rate RCcar / Calculate powder. The calculation result is sent from the odorant substance concentration residual rate estimation unit 204 after the combined treatment to the data processing unit 200b, and is stored in the data processing unit 200b.

The odor-responsive activated carbon injection rate calculation unit 207 uses the data stored in the data processing unit 200b to divide the target odor substance concentration CD with respect to the raw water _A in the coagulation sedimentation treatment by the odor substance concentration _CR . Based on the odorous substance concentration residual rate RCT, the powdered activated carbon injection rate I _car-D , which is the injection rate of the powdered activated carbon _C to be injected into the raw water A for the adsorption treatment of the odorous substance, is calculated. The calculation result is sent from the odor-responsive activated carbon injection rate calculation unit 207 to the data processing unit 200b and stored in the data processing unit 200b.

The activated carbon injection rate calculation unit 203 for organic matter uses the data accumulated in the data processing unit 200b to divide the target ultraviolet absorbance UV _D for the raw water A in the coagulation sedimentation treatment by the ultraviolet absorbance UV _R , and obtains the target ultraviolet absorbance. Based on the residual rate RUV _T , the powdered activated carbon injection rate I _car-UV , which is the injection rate of the powdered activated carbon C to be injected into the raw water A for the adsorption treatment of the soluble organic substance, is calculated. The calculation result is sent from the organic matter-compatible activated carbon injection rate calculation unit 203 to the data processing unit 200b, and is stored in the data processing unit 200b.

The activated carbon injection rate determination unit 209 determines which of the powdered activated carbon injection rate I _car-D and the powdered activated carbon injection rate I _car-UV stored in the data processing unit 200b, whichever is larger, is the powder for the adsorption treatment. Determined as the activated carbon injection rate. Then, the determined powdered activated carbon injection rate is output to the powdered activated carbon injection device 21 as the powdered activated carbon injection rate I _car .

Next, an operation example of the water treatment system to which the water treatment method of the first embodiment of the present invention configured as described above is applied will be described.

FIG. 3 is a diagram showing a flow of treatment by a water treatment system to which the water treatment method of the first embodiment is applied.

First, in the treated water quality target setting unit 100, as the target values of the filtered treated water W after treatment, the target odorous substance concentration C _D , the target ultraviolet absorbance UV _D , the target turbidity Tu _D , the target residual chlorine concentration RCl _D , and the target hydrogen The ion concentration index pH _D and the like are set (S100). These set data are transmitted to the activated carbon injection rate calculation unit 200, received by the data reception unit 200a, and stored in the data processing unit 200b.

In the data processing unit 200b, the target odor substance concentration residual rate _RCT is calculated from the target odor substance concentration CD and the odor substance concentration _CR in the raw water measured by the odor sensor 11 according to the following equation (1) (S201). ).

RC _T = _CD / _CR ... (1)
The data processing unit 200b also calculates the target ultraviolet absorbance residual rate RUV _T from the target ultraviolet absorbance UVD and the ultraviolet absorbance UV _R of the raw water measured by the ultraviolet absorbance meter 12a according to the following equation (2) (S201).

RUV _T = UV _D / UV _R ... (2)
At the same time, in the coagulant injection rate calculation unit 300, the raw water turbidity measured by the target turbidity Tu _D , the turbidity meter 10a, the alkalinity meter 10b, the water temperature meter 10c, and the pH meter 10d of the water quality meter set 10. Degree Tu _R , raw water alkalinity Ark _R , water temperature TR, and hydrogen ion concentration index pH _R , and the admixture pond hydrogen ion concentration index pH _F measured by the pH meter 14 installed in the flocculant admixture pond 30 _. Then, according to the following equation (3), the flocculant injection rate I _{pack for achieving the target turbidity TUD is} calculated (S300).

I _pacl = _f (Tu _D , Tu _R , Alk _R , TR, pH _R , pH _F ) ... (3)
Here, the ultraviolet absorbance RUV _{car / pcl} when the powdered activated carbon treatment and the agglomeration treatment are used in combination, the ultraviolet absorbance residual rate RUV _car after the powdered activated carbon treatment, the ultraviolet residual rate RUV _pacl after the agglomeration treatment, and the combined treatment coefficient _FDOM are used. Then, it is defined as the following equation (4).

RUV _{car / pack} = F _DOM x RUV _car x RUV _pack ... (4)
FIG. 4 is a diagram showing an example of the relationship between the flocculant injection rate I _pack by the flocculant treatment and the ultraviolet absorbance residual rate RUV _pack .

In FIG. 4, the inventors added the flocculant P to the raw water adjusted to the soluble organic carbon concentration DOC _R = 2.5 (mg / L) and the mixed water pH _F = 6.5, and then the rotation speed was 150 ( It is the result of the test of rapid _stirring for 10 minutes at rpm) and then slow _stirring for 60 minutes at a rotation speed of 80 (rpm). The value obtained by dividing the absorbance by UV _R (that is, RUV _pack = UV _pack / UV _R ) is shown. In this test, the mixing ratio of humic acid and fulvic acid was adjusted and added as a soluble organic substance.

FIG. 4 shows three cases of humic acid 100%, humic acid 50% / fulvic acid 50% mixture, and fulvic acid 100%, and the soluble organic substance removal performance by aggregation treatment is affected by the fulvic acid mixing ratio. I understand that I will receive it.

Therefore, the ultraviolet absorbance RUV _sol after the coagulation treatment is calculated by the coagulant injection rate calculation unit 300 according to the following equations (5) and (6) using the relationship of FIG. 4 (S301).

RUV _packl = α × I _packl + β ・ ・ ・ (5)
β = f (pH _F , UV _R , DOC _R , FL _R ) ... (6)
Therefore, the ultraviolet absorbance RUV _sol after the aggregation treatment is expressed as the following function.

RUV _packl = f (I _packl , pH _F , UV _R , DOC _R , FL _R ) ... (6a)
Here, I _pacl is a section corresponding to the flocculant injection rate (mg / L), α is an injection rate constant (−), and β is a section corresponding to I _pacl = 0 (mg / L) in FIG. Pond hydrogen ion concentration index pH _F , E260 _R , which is the ultraviolet absorbance (abs / cm) at a wavelength of 260 (nm) of raw water, soluble organic carbon concentration DOC _R (mg / L), and fluorescence intensity FL _R of raw water. Is calculated using the fluorescence intensity of the fluorescence wavelength with respect to the excitation wavelength. The excitation wavelength and the fluorescence wavelength are preferably 300 (nm) to 350 (nm) and wavelengths of 400 (nm) to 450 (nm), and in this embodiment, the excitation wavelength of 345 (nm) and the fluorescence wavelength of 425 (nm) are particularly preferable. nm).

By the way, the combined treatment coefficient _FDOM shown in the above-mentioned equation (4) is a coefficient showing the combined treatment effect of the powdered activated carbon treatment and the agglomeration treatment.

FIG. 5 is a diagram showing the relationship between the flocculant injection rate I _pacl and the combined treatment coefficient F _DOM .

The results shown in FIG. 5 are the results obtained by the tests by the inventors. In this test, the powder activated charcoal treatment is rapidly stirred at a rotation speed of 150 (rpm) for 60 minutes, the pH is adjusted to a predetermined value, the flocculant P is added, and the mixture is rapidly stirred at a rotation speed of 150 (rpm) for 10 minutes. Then, it was subjected to slow stirring treatment at a rotation speed of 80 (rpm) for 60 minutes.

As shown in the figure, the combined treatment coefficient _FDOM changes greatly depending on the mixing ratio of the organic substances humic acid and fulvic acid to be _added . , The value (F _DOM <1) is smaller than the value obtained by multiplying the UV absorbance residual rate RUV _car after the powdered activated carbon alone treatment and the UV absorbance residual rate RUV _pacl after the flocculant alone treatment (RUV _car × RUV _pacl ). There is a combined use promoting effect, and when the proportion of fulvic acid increases, the UV absorbance residual rate RUV _{car / pcl} of the combined use treatment becomes larger (FDOM ≧ 1) than (RUV _car × RUV _puckl ), and the combined use inhibitory effect. It turned out to be.

Here, in FIG. 5, if the relationship between the combined treatment coefficient F _DOM and the flocculant injection rate I _packl is approximated by the following equation (7) for each mixing ratio of humic acid and fulvic acid, different coefficients f and indexes for each mixing ratio are approximated. n is required.

F _DOM = f × I _pack ⁿ ... (7)
Therefore, as a result of investigating the relationship between the specific absorbance SUVA defined by the following equation (8) as an index close to the mixing ratio of humic acid and fulvic acid in the soluble organic substance in the raw water A, and the coefficient f, the result is shown in FIG. Such a relationship is obtained (S202).

FIG. 6 is a diagram showing the relationship between the specific absorbance SUVA in raw water and the coefficient f.

SUVA = E260 _g / DOC _R (abs ・ L / m ・ mg) ・ ・ ・ (8)
Here, E260R is the ultraviolet absorbance (abs / m) of the raw water A at a wavelength of 260 (nm), and DOCR is the soluble organic carbon concentration (mg / L) of the raw water A.

In the organic substance-compatible activated carbon injection rate calculation unit 203, the powdered activated carbon injection rate Icar-UV corresponding to the soluble organic substance is calculated by the following procedure using the relationship of the above equations (3) to (8) (S203). ..

In order to calculate the powdered activated carbon injection rate Icar-UV, the organic substance-compatible activated carbon injection rate calculation unit 203 first sets the target ultraviolet absorption residual rate RUV _T as RUV _{car / pacl} after the combined treatment of the powdered activated carbon and the flocculant. Using the following equations (9) and (10), the ultraviolet absorbance residual rate RUV _car after the powder activated carbon treatment step is calculated.

RUV _T = RUV _{car / pack} = F _DOM x RUV _car x RUV _pack ... (9)
RUV _car = RUV _T (F _DOM x RUV _pack ) ... (10)
Next, the powdered activated carbon injection rate I _car-UV corresponding to the soluble organic substance is calculated using the isothermal adsorption type relationship shown in the following formula (11).

I _car-UV = f (K _UV , RUV _car , E260 _R , DOC _R ) ... (11)
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 set after being investigated in advance.

In this way, the organic substance-compatible activated carbon injection rate calculation unit 203 calculates the powdered activated carbon injection rate I _car-UV corresponding to the soluble organic substance required to reduce the ultraviolet absorbance UVR of the raw water to UVD.

Next, the effect of removing odorous substances is estimated when the powdered activated carbon injection rate I _{car -UV} for soluble organic substances calculated by the above equation (11) is set to the powdered activated carbon injection rate I car.

FIG. 7 is a diagram showing the relationship between the powdered activated carbon injection rate I _car and the residual odorant concentration rate RC _car after powdered activated carbon treatment.

FIG. 8 is a diagram showing the relationship between the coagulant injection rate Ipac _l and the odorant concentration residual rate RC _{car / pacl} in the combined treatment of powdered activated carbon and coagulant.

7 and 8 are the results obtained by the tests by the inventors, FIG. 7 is the test results regarding the removal characteristics of the odorous substance by the single treatment of the powdered activated carbon C, and FIG. 8 is the odor. It is a test result made about the removal property by the combined treatment of the powder activated carbon C of a substance and a coagulant P.

The test was performed on raw water containing 2-methylisoborneol, which is known as a musty odor substance in raw tap water as an odor substance, and further mixed and added with humic acid and fulvic acid as coexisting organic substances. FIG. 7 shows powdered activated carbon treatment. The relationship between the residual odorant concentration RC _car and the powdered activated carbon injection rate I _car after rapid stirring at a rotation speed of 150 (rpm) for 60 minutes is shown. FIG. 8 shows the powder activated carbon treatment rapidly for 60 minutes at a rotation speed of 150 (rpm). After stirring, adjust the pH to a predetermined value, add the flocculant P, rapidly stir at a rotation speed of 150 (rpm) for 10 minutes, and slowly stir at a rotation speed of 80 (rpm) for 60 minutes. The relationship between the residual rate RC _{car / packl} and the flocculant injection rate I _packl is shown.

In FIG. 8, on the y-axis of the coagulant injection rate I _pacl = 0 (mg / L), the residual odorant concentration after the powdered activated carbon treatment before the coagulation treatment RC _{car / pacl} is shown. The result was that the residual odorous substance concentration RC _{car / powder} after the coagulation treatment was larger than the residual odorous substance concentration RC _car after the activated charcoal treatment. This suggests that the odorous substance once adsorbed by the powdered activated carbon treatment is released in the subsequent coagulation treatment step, and the larger the proportion of fulvic acid in the composition of the coexisting organic substances, the larger the release proportion. It has become.

Based on the above results, in the odorant concentration residual rate estimation unit 204 after the combined treatment, the odorous substance concentration residual rate RC _{car / packl} after the combined treatment, in which the powdered activated charcoal treatment and the aggregation treatment are continuously carried out, is injected with the powdered activated charcoal. Rate I _car (mg / L), flocculant injection rate I _pacl (mg / L), UV absorbance E260 _R (abs / cm) at wavelength 260 (nm) of raw water, which is an index of coexisting organic substances, solubility of raw water The organic carbon concentration DOC _R (mg / L), the fluorescence intensity FL _R of 425 (nm) emitted by the excitation wavelength 345 (nm), and the mixing pond hydrogen ion concentration index pH _F are used to detect fluboic acid. Is estimated (S204). Please refer to equation (12) below.

RC _{car / pack} = f (I _car , I pack, _{E260 R} , DOC _R , FL _R , pH _F ) ... (12)
Next, as shown back to FIG. 3, in the data processing unit 200b, the odorous substance concentration residual rate RC _{car / pack} estimated in step _S204 and the target odorous substance concentration residual rate RCT calculated in step S201 Are compared (S205).

As a result of comparison in step S205, when the odorous substance concentration residual rate RC _{car / packl} is equal to or less than the target _odorous substance concentration residual rate RCT (S205: Yes), the powdered activated carbon injection rate I _car is calculated by the data processing unit 200b as follows (S205: Yes). As shown in the formula 13), the powdered activated carbon injection rate I _car-UV required for removing the soluble organic substance obtained in step S203 is obtained (S206).

I _car = I _car-UV (mg / L) ... (13)
On the other hand, as a result of comparison in step S205, when the value of the odor substance concentration residual rate _{RC car / powder} is larger than the target odor substance concentration residual rate RCT (S205: No), the odor-responsive activated charcoal injection rate calculation unit 207. RC _T is substituted into RC _{car / packl} of the following formula (13a), and the powdered activated carbon injection rate I _car-D required for removing odorous substances is calculated by back calculation (S207).

I _car-D = f (RC _T , RC _{car / pack} , UV _R , DOC _R , I _pack ) ... (13a)
Then, the data processing unit 200b sets the powdered activated carbon injection rate I _car to be the powdered activated carbon injection rate I _car-D required for removing the odorous substance obtained in step S207 (S208).

Next, in the activated carbon injection rate determination unit 209, the larger of the powdered activated carbon injection rate I _car-D required for removing odorous substances and the powdered activated carbon injection rate I _car-UV required for removing soluble organic substances, whichever is larger. Is determined as the powdered activated carbon injection rate for the adsorption treatment (S209), and the powdered activated carbon injection device 21 is controlled by the determined powdered activated carbon injection rate I _car .

In the above description, the residual ratio RUV of ultraviolet absorbance E260 at 260 (nm) is used as a representative index of the soluble organic substance. However, since the soluble organic carbon concentration and the fluorescence intensity of the fluorescence wavelength 425 (nm) with respect to the excitation wavelength 345 (nm) are used in the calculation formula, the residual ratio RUV of the ultraviolet absorbance E260 at 260 (nm) is determined. It can be universally applied as a representative index of soluble organic substances even for fluctuations in raw water and different water sources.

Further, in the above description, the calculation formula is derived based on the test results of FIGS. 7 and 8 in which 2-methylisoborneol is used as the odor substance, but the odor sensor output is also applied to other odors. The relationship between the substance and the substance concentration can be grasped in advance, and the conversion coefficient for 2-methylisoborneol can be used in the same manner.

Further, the above description describes an example in which the soluble organic substance of the raw water is monitored by three types of instruments: an ultraviolet absorbance meter 12a, a fluorescence intensity meter 12b, and a soluble organic carbon concentration (DOC) total 12c. However, the soluble organic carbon concentration DOC _R and the fluorescence intensity FL _R are expressed as linear functions of the ultraviolet absorbance E260 _R as shown in the following equations (14) and (15). Therefore, when the fluctuation of the organic matter composition in the raw water is small in a single raw water system, the following formula (14) can be obtained from the ultraviolet absorbance E260 _R obtained by using an ultraviolet absorbance meter, which is one representative instrument. And, by obtaining the raw water organic carbon concentration DOC _R and the raw water fluorescence intensity FL _R according to the conversion formula shown in the formula (15), the values of other indexes can be obtained with one representative instrument.

DOC _R = a × UV _R + b ... (14)
FL _R = c × UV _R + d ・ ・ ・ (15)
here,
DOC _R : Raw water organic carbon concentration (mg / L),
FL _R : Raw water fluorescence intensity (-),
UV _R : Raw water UV absorbance (abs / cm),
a: UV absorbance, soluble organic carbon concentration conversion coefficient,
b: UV absorbance, soluble organic carbon concentration conversion constant,
c: UV absorbance, fluorescence intensity conversion coefficient,
d: UV absorbance, fluorescence intensity conversion constant,
Is.

Further, as described above, when the soluble organic substance and the odorous substance adsorbed on the powdered activated carbon C are removed by capturing the powdered activated carbon C with the flocculant P, the residual state of the powdered activated carbon C is used as an evaluation index at a wavelength of 260 nm. By using the ultraviolet absorbance E260, it is possible to carry out an appropriate and highly accurate evaluation. That is, by evaluating the state of the powdered activated carbon C using the ultraviolet absorbance E260 and then determining the powdered activated carbon injection rate, the powdered activated carbon injection rate can be determined with high accuracy according to the fluctuation of the water quality of the raw water, and the soluble organic substance can be obtained. Removal of odorous substances is realized. As a result, it is possible to prevent the concentration of soluble organic substances in the filtered water and the target of odorous substances from being exceeded due to insufficient injection of activated carbon powder, and the waste of chemical costs due to excessive injection.

As described above, when the water treatment system 1 to which the water treatment method of the first embodiment is applied removes both the soluble organic substance and the odorous substance by the combined use of the pulverized coal activated coal C and the flocculant P, the raw material is used. The target odorous substance concentration residual rate _RCT , which is the ratio of the treated odorous substance concentration CD to the water odorous substance concentration _CR (= _CD / _{CR ), and the treated ultraviolet absorbance UV D with} respect to the raw water ultraviolet absorbance UV _R. The target ultraviolet absorbance residual rate RUV _T , which is the ratio of (= UV _D / UV _R ), is calculated (S201).

In parallel, based on the target turbidity Tu _D , raw water turbidity Tu _R , raw water alkalinity _{Ark R} , water temperature TR, hydrogen ion concentration index pH _R , and mixing pond hydrogen ion concentration index pH _F , as described above (3). ), The flocculant injection rate I _pcl to achieve the target turbidity _TUD is calculated (S300).

After that, the powdered activated carbon injection rate I _car-UV corresponding to the soluble organic substance is calculated from the relationship between the above-mentioned equations (3) to (10) and the isothermal adsorption equation f shown in the above-mentioned equation (11) (S203). ).

Next, the powdered activated carbon injection rate I _car-UV for soluble organic substances is defined as the powdered activated carbon injection rate I _car , and the flocculant injection rate I _packl , ultraviolet absorbance E260R, soluble organic carbon concentration DOC _R , and fluorescence intensity FL _R. , And, based on the mixing tank pH _F , the residual odorant concentration RC _{car / packl} after the combined treatment with the powdered activated carbon and the flocculant is calculated according to the above-mentioned equation (12) (S204).

When the value of the residual _odorous substance concentration RC _{car / pack} after the combined treatment is equal to or less than the value of the target residual odorous substance concentration RCT (S205: Yes), the value of the powdered activated carbon injection rate I _car is soluble. The powdered activated carbon injection rate for organic substances is set to I _car-UV (S206).

On the other hand, when the value of the residual _odorous substance concentration RC _{car / powder} after the combined treatment is larger than the target residual odorous substance concentration RCT (S205: No), the odorous substance is dealt with according to the above-mentioned equation (13a). The powdered activated carbon injection rate I _car-D is calculated (S207), and the value of the powdered activated carbon injection rate I _car is set to the powdered activated carbon injection rate I _car-D corresponding to the odorous substance (S208).

Then, the larger value of the powdered activated carbon injection rate I _car-D and the powdered activated carbon injection rate I _car-UV was determined as the powdered activated carbon injection rate for the adsorption treatment (S209), and the determined powdered activated carbon was determined. The powdered activated carbon injection device 21 can be controlled by the injection rate I _car .

As described above, according to the water treatment system to which the water treatment method of the first embodiment is applied, powdered activated carbon injection in consideration of the combined effect of powdered activated carbon C and flocculant P on the removal of soluble organic substances and the removal of odorous substances is performed. By doing so, the injection rate _Icar of the powdered activated carbon C can be controlled to be the optimum value according to the change in the water quality of the treated water.

As a result, unnecessary injection of the powdered activated carbon C is suppressed, so that the amount of the powdered activated carbon C, which has been required to be injected in the past, can be significantly reduced, and the filtered water due to insufficient injection of the powdered activated carbon C can be achieved. By avoiding the excess of the target of soluble organic substance concentration and odorous substance and the waste of chemical cost due to excessive injection, it is possible to realize highly economical water treatment.

(Second embodiment)
Next, a water treatment system to which the water treatment method of the second embodiment is applied will be described.

In the present embodiment, duplicate explanations are avoided by using the same reference numerals for the same parts as those in the first embodiment.

FIG. 9 is a block diagram showing a configuration example of a coagulant injection rate calculation unit in the water treatment system of the second embodiment.

The coagulant injection rate calculation unit 300 includes a data reception unit 300a, a data processing unit 300b, an odor substance concentration residual rate estimation unit 302, a coagulant injection rate calculation unit 304, and a coagulant injection rate determination unit 306.

The data receiving unit 300a receives the measurement data from the water quality meter set 10, the odor sensor 11, and the pH measuring device 14.

The data processing unit 300b receives these data received by the data receiving unit 300a from the data receiving unit 300a, performs data processing such as necessary operations using the received data, and stores the result as well. The data stored in the data processing unit 300b in this way (the data from the data receiving unit 300a and the result of the data processing performed by the data processing unit 300b) are the odorous substance concentration residual rate estimation unit 302 and the coagulant injection rate. It can be used by the calculation unit 304 and the coagulant injection rate determination unit 306.

Further, the result calculated by the odorant concentration residual rate estimation unit 302, the coagulant injection rate calculation unit 304, and the coagulant injection rate determination unit 306 is also sent to the data processing unit 300b. As a result, the results calculated by the odor substance concentration residual rate estimation unit 302, the coagulant injection rate calculation unit 304, and the coagulant injection rate determination unit 306 are the odor substance concentration residual rate estimation unit 302 and the coagulant injection rate calculation unit. It is shared by 304 and the flocculant injection rate determination unit 306.

The odorant concentration residual rate estimation unit 302 divides the target odorous substance concentration _{C D} with respect to the raw water in the coagulation sedimentation treatment by the odorous substance concentration _CR to obtain the target odorous substance concentration residual rate RCT (= _CD / _CR ). ), _Which is the injection rate of _powdered activated charcoal C to be injected into raw water for _adsorption treatment of soluble organic matter. Using the specific absorbance SUVA (= E260 _R / DOC _R ) obtained by dividing by and the coagulant injection rate I _pack obtained according to the above-mentioned formula (3), the powdered activated carbon according to the above-mentioned formula (12). The estimated value RC _{car / packl} of the residual odorant concentration in the raw water A after the coagulant is treated in combination is calculated.

When the coagulant injection rate calculation unit 304 has a larger value than the target _odorant concentration residual rate RCT in the odorous substance concentration residual rate estimated value RC _{car / packl} , the odorous substance concentration by the combined treatment set in advance is set. Using the residual rate characteristic prediction formula (I _pack-D = f (RC _T , RC _{car / pack} , UV _R , DOC _R , I _car-UV )), the estimated residual rate of odorous substance concentration RC _{car / packl} was determined. The coagulant injection rate I _{packl -D} , which is the coagulant injection rate required to match the target odorant concentration residual rate RCT, is calculated.

When the value of the coagulant injection rate I paccl is equal to or higher than the value of the coagulant injection rate I _paccl-D (I _paccl-D ≤ I _paccl ), the coagulant injection rate determining unit 306 determines the coagulant injection rate I _{paccl .} The value is taken as the coagulant injection rate in the coagulation sediment, and conversely, when the coagulant injection rate I _{packl -D} has a larger value than the coagulant injection rate I packl (I _packl-D > I _packl ). The value of the coagulant injection rate I _packl-D is taken as the coagulant injection rate in the coagulation precipitate.

Next, an operation example of the water treatment system to which the water treatment method of the second embodiment configured as described above is applied will be described.

FIG. 10 is a diagram showing a flow of treatment by a water treatment system to which the water treatment method of the second embodiment is applied.

The flow of the treatment in the present embodiment is different from that of the first embodiment when the odorant removal is insufficient at the powder activated carbon injection rate for soluble organic substances, but the other cases are the same. , The same processing site as in FIG. 3 is assigned the same step number.

Therefore, the differences from FIG. 3 will be described below.

In the present embodiment, unlike the first embodiment, the powdered activated carbon injection device 21 is controlled by the powdered activated carbon injection rate Icar-UV corresponding to the soluble organic substance calculated in step S203.

Further, in the present embodiment, the odorant concentration residual rate estimation unit 302 calculates the odorous substance concentration residual rate estimation value RC _{car / packl} in the raw water A after the powdered activated carbon C and the flocculant P are treated in combination. (S204a). The details of the calculation method are as described in step S204.

Further, in the present embodiment, unlike the first embodiment, when RCcar / pac _l is RCT or less in step S205 (S205: Yes), the aggregating agent injection rate Ipac _l calculated in step S300 is used as the aggregating agent. The injection device 31 is controlled (S218: Yes, S219).

On the other hand, in step S205, when the value of RCcar / pac _l is larger than that of RCT (S205: No), the coagulant injection rate calculation unit 304 is used in combination with the coagulant injection rate Ipac _l in FIG. Residual rate According to the relationship of RC car / pac _l , the odorant concentration residual rate characteristic prediction formula (I _pacl-D = f (RC _T , RC _{car / paccl} , UV _R , DOC _R , I _car-UV )) by combined treatment was used. Using this, the coagulant injection rate Ipac _l -D corresponding to the odorant whose RCcar / pac _l matches the target odorant concentration residual rate RCT is calculated (S217). The calculated coagulant injection rate Ipac _l -D corresponding to the odorous substance is sent to the data processing unit 300b and held by the data processing unit 300b. Further, the data processing unit 300b also holds the flocculant injection rate Ipac _l calculated in step S300.

After step S217, in step S218, the value of the coagulant injection rate Ipac _l −D corresponding to the odorous substance held in the data processing unit 300b and the value of the coagulant injection rate Ipac _l determine the coagulant injection rate. Compared by unit 306. When the value of the flocculant injection rate I _packl is equal to or higher than the value of the flocculant injection rate I _packl-D corresponding to the odorous substance (S218: Yes), the value of the flocculant injection rate I _packl is the aggregation in the coagulation sediment. The agent injection rate is defined, and the coagulant injection device 31 is controlled by the value of the coagulant injection rate I _pack (S219). On the other hand, when the value of the flocculant injection rate I _packl -D corresponding to the odorous substance is larger than that of the flocculant injection rate I _packl (S218: No), the coagulant injection rate I _packl-D corresponding to the odorous substance is found. The value is taken as the coagulant injection rate in the coagulation sediment, and the coagulant injection device 31 is controlled by the value of the coagulant injection rate I _packl-D (S220).

As described above, according to the water treatment system to which the water treatment method of the second embodiment is applied, when the removal of odorous substances is insufficient with the powdered activated carbon injection rate Icar-UV for soluble organic substances, the unit price is Since the residual rate of odorous substance concentration can be reduced by increasing the injection rate of the relatively inexpensive flocculant P without increasing the injection rate of the high powdered activated carbon C, it is possible to suppress an excessive increase in chemical costs. It will be possible. Further, since the injection rate of the powdered activated carbon C can be minimized, it is possible to reduce the amount of sludge generated and suppress the increase in the disposal cost thereof.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 ... Water treatment system, 2 ... Water treatment equipment, 3 ... Water treatment facility, 10 ... Water quality meter set, 10a ... Turbidity meter, 10b ... Alkaliity meter, 10c ... Water temperature gauge, 10d ...・ PH meter, 11 ・ ・ Odor sensor, 12 ・ ・ Soluble organic substance index meter set, 12a ・ ・ Ultraviolet absorptiometer, 12b ・ ・ Fluorescence intensity meter, 12c ・ ・ Soluble organism carbon concentration (DOC) meter, 13 ・・ Flow meter, 14 ・ ・ pH measuring device, 15 ・ ・ Filtered water UV transmission meter, 20 ・ ・ Watering well, 21 ・ ・ Powdered activated charcoal injection device, 22 ・ ・ Sodium hypochlorite injection device, 23 ・ ・ Oxidation Agent injection device, 30 ... Aggregator mixing pond, 31 ... Aggregator injection device, 32 ... Stirrer, 40 ... Flock forming pond, 40a ... Stirring pond, 40b ... Stirring pond, 50 ... Precipitation pond , 60 ... Filtration pond, 60a ... Filtration layer, 61 ... Alkaline agent injection device, 70 ... Water purification pond, 71 ... Sodium hypochlorite injection device, 72 ... Alkaline agent injection device, 80 ... Water supply Water quality meter set, 80a ... turbidity / chromaticity sensor, 80b ... residual salt concentration sensor, 80c ... pH sensor, 80d ... water temperature sensor, 91 ... piping, 92 ... piping, 100 ... treated water quality target setting Unit, 200, 200A ... Activated charcoal injection rate calculation unit, 200a ... Data receiving unit, 200b ... Data processing unit, 203 ... Activated charcoal injection rate calculation unit for organic substances, 204 ... Estimating residual odorous substance concentration after combined treatment , 204a ... Odor substance concentration residual rate estimation unit, 207 ... Odor-compatible activated charcoal injection rate calculation unit, 209 ... Activated charcoal injection rate determination unit, 230 ... Odor substance concentration residual rate calculation unit, 230 ... Odor substance concentration Residual rate calculation unit, 240 ... Odor substance concentration residual rate update unit, 300 ... Coagulant injection rate calculation unit, 300a ... Data reception unit, 300b ... Data processing unit, 302 ... Odor substance concentration residual rate estimation unit , 304 ... Coagulant injection rate calculation unit, 306 ... Coagulant injection rate determination unit

Claims (8)

A first coagulant injection rate calculation unit that calculates a first coagulant injection rate, which is an injection rate of a coagulant required for coagulation and precipitation of the turbidity of the raw water based on the water quality of the raw water.
The odor of the raw water is based on the concentration of the odorous substance in the raw water, at least one of the ultraviolet absorbance, the fluorescence intensity, and the soluble organic carbon concentration of the raw water, and the injection rate of the first flocculant. An activated carbon injection rate calculation unit that calculates the first powdered activated carbon injection rate, which is the injection rate of powdered activated carbon required for removing substances, and
Water treatment system equipped with. The activated carbon injection rate calculation unit is
The second powdered activated carbon, which is the injection rate of the powdered activated carbon required for the adsorption treatment of the odorous substance, based on the target odorous substance concentration residual rate obtained by dividing the target odorous substance concentration with respect to the raw water by the odorous substance concentration. Odor-responsive activated carbon injection rate calculation unit that calculates the injection rate,
A third powder, which is the injection rate of powdered activated carbon required for the adsorption treatment of soluble organic substances in the raw water, based on the target ultraviolet absorbance residual rate obtained by dividing the target ultraviolet absorbance with respect to the raw water by the ultraviolet absorbance. The activated carbon injection rate calculation unit for organic substances that calculates the activated carbon injection rate, and
It has an activated carbon injection rate determining unit that determines the larger value of the second powdered activated carbon injection rate and the third powdered activated carbon injection rate as the powdered activated carbon injection rate.
The water treatment system according to claim 1. The first coagulant injection rate calculation unit is
The target odorous substance concentration residual rate obtained by dividing the target odorous substance concentration with respect to the raw water by the odorous substance concentration, the ultraviolet absorbance, the soluble organic carbon concentration, and the first flocculant injection rate. Based on this, an odorant concentration residual rate estimation unit that calculates an odorous substance concentration residual rate estimation value in the raw water after the powdered activated charcoal and the flocculant are combinedly treated.
When the estimated odorous substance concentration residual rate is larger than the target odorous substance concentration residual rate, it is necessary to match the odorous substance concentration residual rate estimated value with the target odorous substance concentration residual rate. A second coagulant injection rate calculation unit for calculating a second coagulant injection rate, which is a coagulant injection rate, and a second coagulant injection rate calculation unit.
When the value of the first coagulant injection rate is equal to or higher than the value of the second coagulant injection rate, the first coagulant injection rate is determined as the coagulant injection rate, and the first coagulant injection rate is determined. When the value of the second coagulant injection rate is larger than the injection rate, it has a coagulant injection rate determining unit that determines the second coagulant injection rate as the coagulant injection rate.
The water treatment system according to claim 1. The activated carbon injection rate calculation unit is
The target odorous substance concentration residual rate obtained by dividing the target odorous substance concentration with respect to the raw water by the odorous substance concentration, the ultraviolet absorbance, the soluble organic carbon concentration, and the first flocculant injection rate. Based on this, an odorant concentration residual rate estimation unit that calculates an odorous substance concentration residual rate estimation value in the raw water after the powdered activated charcoal and the flocculant are combinedly treated.
When the estimated odorous substance concentration residual rate is larger than the target odorous substance concentration residual rate, after the coagulation sedimentation, based on the odorous substance concentration residual rate estimated at the current powdered activated carbon injection rate. The odorous substance concentration residual rate calculation unit that calculates the odorous substance concentration residual rate, and
It has an odorant concentration residual rate update unit having a value obtained by dividing the target odorous substance concentration residual rate by the odorous substance concentration residual rate after coagulation sedimentation as a new target odorous substance concentration residual rate value.
The water treatment system according to claim 1. The water treatment system according to claim 1, wherein the soluble organic carbon concentration and the fluorescence intensity are expressed as a linear function of the ultraviolet absorbance. The water treatment system according to any one of claims 1 to 5, wherein the ultraviolet absorbance is the absorbance of ultraviolet rays emitted from an ultraviolet light source at a wavelength of 260 nm obtained from the raw water. In order to detect fulvic acid contained in the raw water, the fluorescence intensity is included in the wavelength range of 400 nm to 450 nm emitted from the raw water by irradiation with ultraviolet rays at an excitation wavelength included in the excitation wavelength range of 300 nm to 350 nm. The water treatment system according to any one of claims 1 to 5, which is obtained at a certain wavelength. Based on the water quality of the raw water, the first coagulant injection rate, which is the injection rate of the coagulant required for the coagulation and precipitation of the turbidity of the raw water, was calculated.
The odor of the raw water is based on the concentration of the odorous substance in the raw water, at least one of the ultraviolet absorbance, the fluorescence intensity, and the soluble organic carbon concentration of the raw water, and the injection rate of the first flocculant. Calculate the first powdered activated carbon injection rate, which is the injection rate of powdered activated carbon required for removing substances.
Water treatment method.

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