JPH07246384A - Water purifying treatment and water purifying treatment device - Google Patents

Abstract

PURPOSE:To execute a water purifying treatment with high responsiveness meeting water quality by determining a normal absorbance value at the time of determining a correlation between the absorbance of test water and the concn. of materials to be removed and executing the water purifying treatment in such a manner that the value of the absorbance of the test water after the water purifying treatment attains the normal absorbance value or below. CONSTITUTION:The water purifying treatment device for executing mainly an ozone treatment has a water tank 1 for the water to be ozone treated in which raw water (the water to be ozone treated) is stored, an ozone treatment column 2 which executes the ozone treatment, an ozonizer 3 which supplies ozone to the ozone treatment column 2 and an ozone treated water tank 4 in which the water after the ozone treatment is stored. The absorbance value of the test water after the ozone treatment is determined from the correlation between the absorbance value of the test water before the ozone treatment and a correlation storage section in a control section 7 to which the respective measured values of UV meters (a), (b), flow meters QLa, b and gaseous phase ozone concn. meter 6, etc., are inputted. The amt. of the ozone to be injected necessary for decreasing the absorbance value to the normal absorbance value or below is determined, by which the ozonizer 3 is controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water purification technology, and more particularly to an advanced water purification technology for removing organic substances, musty odor substances, trihalomethanes, etc. contained in water to be treated.

[0002]

2. Description of the Related Art In recent years, various harmful substances have been detected in rivers, lakes and marshes, which are tap water sources, and correspondingly, on December 1, 1993, the number of regulated items increased significantly. New tap water quality standards have been enforced.

According to the new water quality standards of this time, many volatile organic chlorine compounds, musty odor substances, pesticides, and disinfection by-products, which are difficult to deal with in the present water treatment, are added to the regulation items. Under such circumstances, the importance of advanced water treatment equipment using ozone and activated carbon is increasing.

In particular, total trihalomethane (T
For HM) a reference value of 0.1 mg / L was shown. The THM of clean water is mainly produced by chlorine disinfection in the water purification process.
In order to reduce THM, methods such as changing chlorine disinfection to another disinfection method, removing THM produced, and removing precursors of THM can be considered.

However, since chlorine disinfection is unavoidable in the present water purification treatment, and adsorption of activated carbon as a method for removing THM itself and aeration are ineffective at a high cost, the THM precursor is removed. Becomes a problem.

The advanced treatment (ozone,
With activated carbon treatment), THM precursor can be removed.
There are expectations as a method for removing or reducing THM. Currently, THM precursors are measured as their ability to produce THM (THM concentration produced under certain conditions, hereinafter THMFP).

Advanced water purification treatment facilities for performing such advanced water purification treatment were introduced in 12 water purification plants in 1990. These facilities are aimed at removing organic substances such as musty odor, chromaticity, trihalomethane and potassium permanganate consumption.

Ozone treatment, which is one of the advanced water purification treatments,
Bacteria in water, due to the strong oxidizing power of ozone,
It disinfects bacteria and oxidizes and removes trace amounts of soluble harmful substances dissolved in water.

Generally, the ozone injection rate is used as an operating condition for the operation of the ozone treatment facility. Here, the ozone injection rate (D) is shown in the following formula.

[0010]

[ _Equation 1] D = C0 _3in * q0 ₃ / QL D: ozone injection rate (mg / l) C0 _3in : injected ozone concentration (g / Nm ³ ) q0 ₃ : ozone gas injection amount (l / min) QL: treated water amount (l / min) Generally, the ozone injection rate in a water purification plant is about 2-3 mg / l, although it varies depending on the type and concentration of the substance to be treated. This ozone injection rate is obtained in advance by laboratory experiments or the like for the ozone treated water of each water purification plant.

Further, continuously measuring and monitoring THMFP of the treatment process water is an important factor for grasping the treatment situation of each treatment process and controlling THM generated by chlorine sterilization in the subsequent stage. ing.

[0012]

In controlling the ozone injection rate, the concentration of harmful substances such as THMFP is measured continuously and in real time, and it is efficient to keep the concentration of these harmful substances below the reference value. It is preferable to perform control.

However, for example, in order to measure THMFP, it is necessary to use an analytical instrument such as a gas chromatograph (GC) or a gas chromatograph-mass spectrometer (GC-MS) in a dedicated analysis room, and the measurement time is 24 hours. It takes more time. Moreover, it is very difficult to continuously measure the process water.

As described above, the ozone treatment effect cannot be grasped for substances that cannot be continuously and automatically monitored (eg, musty odor substances).

Therefore, as described above, in the actual ozone treatment facility, the injected ozone concentration is determined so that the ozone injection rate set by the indoor experiment or the like is determined with respect to the planned water amount. That is, the constant ozone injection rate is controlled.

In the constant ozone injection rate control, when the water quality of the ozone treated water changes, the injected ozone amount becomes insufficient or excessive. That is, the ozone treatment effect is reduced, the ozone operation is wasted, and the operation cost is increased.

If the injected ozone amount is excessive,
This causes an increase in the amount of exhaust ozone, which increases the load on the exhaust ozone treatment facility. When the amount of injected ozone is small, the ozone treatment effect is reduced and the quality of the ozone-treated water is deteriorated.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a water purification technology capable of promptly performing flexible water treatment according to the quality of water to be treated.

[0019]

Means and Actions for Solving the Problems In order to solve the above problems, the present invention obtains a correlation between the absorbance of sample water and the concentration of a substance to be removed, and uses the correlation to correspond to a specified concentration of the substance to be removed. There is provided a water purification treatment method, characterized in that the water absorption treatment is performed so that the absorbance value of the test water after the water purification treatment becomes equal to or less than the prescribed light absorption value.

By performing the water purification treatment in this manner, the concentration of the substance to be removed in the test water is controlled to be equal to or lower than the specified concentration by measuring only the absorbance without directly measuring the concentration of the substance to be removed. .

When measuring the concentration of a substance to be removed, it often takes a long time to measure the concentration, and in such a case, it is difficult to control the water purification treatment efficiently, and the water purification in real time is difficult. Process control is very difficult.

On the other hand, since the absorbance can be measured quickly, the water purification treatment can be quickly controlled regardless of the type of the substance to be removed, and the water purification treatment control in real time is easy. realizable.

As the wavelength of this absorbance, it is preferable to use a wavelength having a high correlation with the substance to be removed. For example, when the organic matter in the test water is to be removed, it is preferable to perform measurement using ultraviolet rays, particularly ultraviolet rays having a wavelength of about 254 (nm). E260 measurement is known as such a measurement method, and it is particularly preferable to perform such measurement.

Further, the absorbance of the test water before the water purification treatment is detected, and the correlation between the progress of the water purification treatment and the absorbance of the water test is obtained,
Using this correlation and the absorbance value of the test water before the water purification treatment, the water purification value after the water purification treatment is obtained by determining the prescribed degree of progress of the water purification treatment required to make the absorbance value below the prescribed absorbance value. There is also provided a water purification method characterized by controlling the progress of the treatment.

With such a control method, it is possible to know to what extent the water purification treatment should proceed, and the water purification treatment can be performed quickly and efficiently. For example, when activated carbon treatment is performed as water purification treatment, the contact time with activated carbon or the like corresponds to the degree of progress, and in ozone treatment, the contact time and injected ozone concentration correspond to the degree of progress.

By obtaining these prescribed progress rates, prescribed values such as processing time, contact time, and injection concentration can be obtained. Since the target value of the water purification process is specifically obtained in this way, efficient control is performed by performing the water purification process using this value as the target value at that time.

A suitable example of the water purification treatment is ozone treatment. In this case, the ozone injection amount is used as the degree of progress of the water purification process, and the ozone injection amount is controlled by the specified ozone injection amount necessary for making the absorbance value of the test water after the water purification process equal to or less than the specified absorbance value.

When measuring the absorbance by E260, the value of the absorbance is influenced by the ozone concentration, so it is preferable to use a value corrected for this influence.

Further, by obtaining the absorbance of the test water after the water purification treatment and comparing the absorbance with the specified absorbance value to correct the progress of the water purification treatment, more efficient water purification treatment control can be performed. Be seen.

As a water purification apparatus for performing such water purification treatment, there is provided a water purification apparatus having an ozone treatment unit for removing a substance to be removed by an ozone treatment in which ozone is injected into the water to be detected. A storage unit for the value, a measurement unit for measuring the absorbance of the test water before ozone treatment, and a correlation storage unit for storing the correlation between the ozone injection amount for the test water and the absorbance of the test water,
From the absorbance value of the test water before ozone treatment, and the correlation obtained from the correlation storage unit, from the correlation value obtained from the correlation storage unit, obtain the ozone injection amount necessary to make the absorbance value of the test water after ozone treatment equal to or less than the specified absorbance value. There is also provided an ozone injection amount control unit for controlling the ozone injection amount according to the present invention.

[0031]

Embodiments of the present invention will be described below with reference to the drawings. In this example, the correlation between the organic substance concentration after the ozone treatment and the injected ozone concentration was obtained, and the injected ozone concentration necessary for making the organic substance concentration after the ozone treatment below the target value was obtained. Since the value of E260 can be measured quickly,
By obtaining this correlation, it becomes possible to control the injected ozone concentration in real time.

Next, the correlation between the musty odor substance concentration, the trihalomethane-forming ability (THMFP) and E260 was determined. If the correlation between these substances and E260 can be obtained, the injected ozone concentration necessary for making these values below the target value can be obtained by using the correlation formula between the organic substance concentration and the injected ozone concentration for these substances. You can Hereinafter, an example of controlling the injected ozone concentration by obtaining a correlation formula for each substance will be shown.

Example 1: Example of control of injected ozone concentration with respect to organic substance concentration and musty odor substance concentration FIG. 1 shows a water purification apparatus according to this example.

This water purifying apparatus mainly performs ozone treatment, and the raw water to be treated (ozone treated water)
An ozone treated water tank 1 that stores ozone, an ozone treatment tower 2 that performs ozone treatment on ozone treated water, an ozonizer 3 that supplies ozone to the ozone treatment tower 2, and an ozone treated water tank 4 that stores ozone treated water. Have.

The flow meter QL1 measures the flow rate of the ozone-treated water from the ozone-treated water tank 1 to the ozone treatment tower 2, and the flow rate QL2 is the ozone-treated ozone-treated water flowing from the ozone treatment tower to the ozone-treated water tank. Measure the flow rate of.

Ozone generated by the ozonizer 3 is diffused through the diffuser 5 to the ozone-treated water in the ozone treatment tower. The flow rate of the discharged ozone is measured by the discharged ozone gas flow meter qG2. After that, part of the exhausted ozone was generated by the ozonizer 3.
It is returned to the ozone treatment tower 2 again together with the ozone generated in 1. Other waste ozone is carried to the waste ozone treatment tower for processing.

The injected ozone gas flow meter qG1 measures the flow rate of ozone gas (including exhaust ozone gas) flowing into the ozone treatment tower.

The gas-phase ozone concentration meter 6 measures the ozone concentrations of ozone generated by the ozonizer and exhaust ozone.

The UV meters a and b are ultraviolet absorptiometers,
The UV meter a measures the concentration of organic substances in the ozone-treated water flowing into the ozone treatment tower. The UV meter b measures the concentration of organic substances in the ozone-treated water flowing out from the ozone treatment tower.

The respective measured values obtained from the UV meters a and b, the flow meters QLa and b, the ozone gas flow meters a and b and the gas phase ozone concentration meter are sent to the control unit (CPU / DDC).

The control unit 7 controls the ozonizer based on these values, and determines the injected ozone concentration necessary for the ozone concentration in the ozone-treated water to be equal to or lower than the preset allowable organic substance concentration.

In this embodiment, 2 is used as an organic matter index.
UV absorption of 60nm (E260) is selected and UV
Continuous automatic monitoring of ozone-treated water and ozone-treated water is carried out with a total of a and b. Similarly, for musty odor substances, E260 is similarly measured using UV meters a and b to monitor the ozone treatment effect.

First, an indoor experiment is conducted in advance to find the relationship between the residual ratio of the organic matter concentration (E260) due to ozone and the ozone contact time θ. Fig. 2 shows the residual ratio of E260 (ratio of ozone treated water concentration Ci to ozone treated water concentration Co)
And the ozone contact time θ.

From FIG. 2, the removal rate of E260 by ozone can be obtained. FIG. 3 shows the relationship between the removal rate [reaction rate constant (1 / min)] ko ₃ of ozone and E260 obtained from FIG. 2 and the amount of absorbed ozone. From FIG. 3, the relational expression between k0 ₃ and the absorbed ozone amount (ηD) is shown below.

[0045]

[Equation 2] k0 ₃ = 0.2367 * (ηD) ^{0 ・ 6733} (1) Further, the equation showing the mass balance equation of E260 by ozone treatment is given by the equation (2).

..

Equation 3] V (dCo / dt) = Q (Ci-Co) -VRo 3 (2) Ci: E260 value before ozone treatment [ozone water to be treated E
260 value] (abs) Co E260 value after ozone treatment [E26 of ozone-treated water
0 value] (abs) θ (= V / QL): ozone contact time (min) V: ozone treatment tower capacity (l) QL: ozone treated water amount (l / min) Ro ₃ : E260 removal rate by ozone treatment (abs) 2) Since the reaction rate Ro ₃ can be approximated to the first-order reaction from FIG. 2, the following equation holds.

[0047]

[Equation 4] Ro ₃ = (dCo / dt) = ko ₃ Co (3) From the equation in the steady state (dCo / dt = 0) in the equation (2) and the equation (3), ko ₃ and E260 value are obtained. Equation (4) showing the correlation of is obtained.

[0048]

Co / Ci = 1 / (1 + ko ₃ · θ) (4) By substituting the equation (1) into the equation (4), the equation (5) representing the ozone-treated water concentration is obtained.

[0049]

[Equation 6] Co / Ci = 1 / (1 + 0.2367 * (ηD) ^{0 · 6733} · θ) (5) The absorbed ozone amount (ηD) is expressed by the following formula.

[0050]

[Equation 7] _{ηD = (Co 3 in-Co} 3out) * qo 3 / QL (6) Co 3 in: injecting ozone concentration _{^{(g / Nm 3) Co 3}} out: exhaust ozone concentration (g / Nm ^3), qo ₃ : Flow rate of injected ozone (l / min) Here, in the formula (6), the exhaust ozone concentration Co ₃ out = 0
Can be approximated, and at this time, the equation (4) becomes the following equation.

[0051]

[Equation 8] _{ηD = Co 3 in * qo 3} / QL (7) (5) equation (6) If you clear the ηD from the equation, injecting ozone concentration Co ₃ in the _{Co 3out, Co, Ci, θ} , qo 3 , QL.

Especially, when Co _3out = 0,
By removing ηD from the equations (5) and (7), the injected ozone concentration Co ₃ in is represented by a function of Co, Ci, θ, qo ₃ and QL.

Here, qo ₃ is qGa in FIG. 1, and QL
Is monitored by QLb, and θ is calculated from V / QL. Also, the E260 value Ci of ozone-treated water is U
It is measured by the V meter a and can be treated as a known value.

In this way, the injected ozone concentration Co _3in is Co
, And Co _{3out as} a function of Co _3out , if the value of Co _3out is set by an appropriate method, then Co _3in can be determined by the following correlation equation with Co as an unknown.

[0055]

## _EQU9 ## Co _3in = f (Co) In this example, Co _3in was determined with Co _3out = 0 as in the equation (7). The value of Co _3out can be appropriately set by another method. For example, the value of Co _3out has less variation than the values of the other parameters, so its average value may be used as a fixed value.

When performing purified water treatment, E2 of ozone-treated water
Although it is required to adjust the injected ozone concentration so that the value of the 60-value Co becomes a certain value or less, according to the present embodiment,
When a target value is set for the value of Co, using the above correlation equation,
The value of Co _3in corresponding to that value can be calculated.

Further, since the E260 measurement can be continuously monitored, the value of the ozone injection amount Co ₃ can be quickly controlled to the optimum value.

Furthermore, since the UV meter b monitors the current value of Co, by correcting the injected ozone concentration Co _3in using this value, more efficient ozone injection control can be performed. In this example, the injected ozone concentration Co _3in was controlled, but Co _3in and qG1
Since the product of and is the ozone injection amount, it is essentially the same as the configuration for controlling the ozone injection amount. The same applies to the following examples.

Next, a control method for a musty odor substance, which is one of the substances which gives offensive odor damage to tap water, will be described.

In this case as well, as in E260, U
Monitoring is performed using V meters a and b. Fig. 4 shows that one of the musty odorous substances, 2-methylisoborneol (2MI
The relationship between the residual ratio of B) and E260 and the ozone contact time θ is shown.

From FIG. 4, the relationship between the residual ratio of each water quality and the ozone contact time is approximated by the following equations.

[0062]

[ _Equation 10] (Co / Ci) _2MIB = EXP (-0.155 ・ θ) (8) (Co / Ci) _E260 = EXP (-0.071 ・ θ) (9) From both equations (8) and (9), (Co / Ci) _2MIB / (Co
/ Ci) _E260 gives the following formula.

[0063]

[ _Equation 11] (Co / Ci) _2MIB / (Co / Ci) _E260 = EXP (-0.084 · θ) (10) From this formula, by monitoring E260 of ozone-treated water and treated water, it is possible to detect musty substances. The residual ratio of a certain 2MIB can be estimated. The concentration of 2MIB is obtained from the above-mentioned residual ratio and the concentration of 2MIB in the water to be treated.

Therefore, if the target value is set to 2 MIB, 2
Since the target value of E260 for the MIB is determined, the optimum value of Co _3in can be obtained from this target value.

A method of controlling the organic matter concentration and musty odor substance concentration is shown in the flowchart of FIG.

In this control method, the correlation equation between Co and Co _3in is obtained in advance. Then, for the organic substance concentration and musty odor substance concentration, the target value of Co is set from the respective target values (S1). After that, the value of each parameter such as θ, qo ₃ , and QL is detected (S2).

Substituting the obtained value into the correlation equation (S3), C
o _3in is calculated (S4). Then, the ozonizer is controlled so that the value of Co _3in becomes the value obtained above (S
5).

Further, the measured value of Co is detected (S6), and Co
If the value of does not match the target value, the value of Co _3in is corrected (S7, S8). This control is repeated until the water purification process is completed (S9).

As described above, the correlation between Co _3in and Co is obtained in advance, and the value of each parameter required for water purification treatment is measured to reduce the organic matter concentration and musty odor substance to below the target values. You can find the required Co _3in .

Example 2 Example of Controlling Injection Ozone Concentration for Trihalomethane Production Ability In this example, E260 was measured using the UV meter shown in FIG. 6, and THMFP after ozone treatment and activated carbon treatment was measured from the measured value. By continuously obtaining these values, the ozone injection amount required to bring these values below the target values was obtained.

First, E260 (50 mm cell for each treatment process water in the advanced water treatment plant (combined treatment with ozone and activated carbon) that treats 20 m ³ per day as coagulation sedimentation water of a water purification plant using dam lake water as a water source is used. Used 254
(UV absorptance of nm), and the average removal rate of THMFP with respect to raw water.

As a result, in the ozone treatment, E260
Is 62.2% while THM is 40.7%.
It became%. On the other hand, in the ozone / activated carbon treatment, values of 74.8% for E260 and 72.6% for THMFP were obtained, which were comparable.

From the above, the final removal rates after activated carbon treatment are similar for both indicators, whereas the removal rates for both indicators after ozone treatment are different. From the above, E26
7 and 8 are plots of the relationship between 0 and THMFP divided into two systems, coagulated water and ozone-treated water, and coagulation and activated carbon-treated water. It was confirmed that each THMFP can be estimated by measuring E260 of ozone-treated water and activated carbon-treated water by dividing the two systems into two systems as described above.

From the graph of FIG. 7, the measured value of E260 is e
As a result, the following equation is obtained.

[0075]

## EQU12 ## Coagulation / O ₃ processing system: THMFP (μg / L) = 189.5 × e + 120 Correlation coefficient r = 0.731 (n = 56) Similarly, the following equation is obtained from the graph of FIG.

[0076]

[Equation 13] Coagulation / activated carbon treatment system: THMFP (μg / L) = 240.2 × e + 0.59 Correlation coefficient r = 0.873 (n = 140) From the above results, the water treatment equipment shown in FIG. Control was performed.

In FIG. 9, a UV meter is installed in an ozone-treated water tank (coagulation / sedimentation water tank), an ozone-treated water tank, and an activated carbon-treated water tank. After passing through a measuring cell length of 50 mm, each signal of a UV signal (ultraviolet absorptivity (abs) at 254 nm) and a VIS signal (absorptivity (abs) at 546 nm) is measured.

From the UV signal or the UV-VIS signal (turbidity correction signal), T-THMFP (total of each forming ability of chloroform, dichlorobromomethane, chlorodibromomethane and bromoform) corresponding to each test water is estimated. , UV signal and VIS signal are output respectively.

The E260 value of the ozone treated water was measured with a UV meter to measure the E2 in the ozone treatment section and activated carbon treatment section in the subsequent stage.
Target values of 60 values are set respectively.

In the ozone processing section, ozone processing is performed until the E260 value becomes smaller than the target value set in the ozone processing section. Similarly, the activated carbon treatment unit performs the activated carbon treatment until the E260 value becomes smaller than the E260 value set in the activated carbon treatment unit.

Thus, using the E260 value, THM
By controlling the ozone / activated carbon treated water so that the FP becomes smaller than the target value, the THMFP of each sample water can be estimated and the treatment status can be grasped, and the ozone treatment unit and the activated carbon treatment unit can be efficiently used. It becomes possible to control.

When the UV meter is installed in the ozone-treated water tank in the above Examples 1 and 2, it is necessary to consider the influence of dissolved ozone. The maximum absorption band of ozone is in the vicinity of 254 nm, and when the UV meter of the present invention is used as it is in the presence of dissolved ozone, the UV signal is output after absorption by dissolved ozone is added.

Therefore, when ozone-treated water is measured using this UV meter, it is necessary to correct the absorbed amount by measuring the dissolved ozone concentration in the test water. Thus, the method of correcting the dissolved ozone concentration is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 5-12102 and 5-12101.

Further, in this embodiment, since the constant cell is of the flow cell type, the UV value and the turbidity correction U
The V value can be continuously measured. By continuously measuring the UV values in the flow cell format in this way, THMFP can be estimated continuously without any time error.

In each of the above-mentioned embodiments, 254 (nm) is mainly used as the wavelength of the light beam at the time of absorption measurement, but any wavelength can be used as long as it can be correlated with the organic matter concentration, musty odor substance concentration and THMFP. Usually, ultraviolet rays are used as such a wavelength, and it is particularly preferable to use E260, which has a high correlation with the concentration of organic substances, as in the above embodiment.

[0086]

As described above, according to the present invention,
Regardless of the type of substance to be removed, the water purification treatment can be quickly controlled, and the water purification treatment control can be performed in real time.

Further, by measuring the absorbance of the test water before the water purification treatment and obtaining the prescribed progress degree of the water purification treatment necessary for making the absorbance value of the test water after the water purification treatment equal to or less than the prescribed absorbance value. The concentration of injected ozone can be set according to the quality of the water to be treated.

As described above, since the water purification treatment can be progressed according to the quality of the test water, the operation can be performed at an optimum degree of progress. Therefore, the excessive progress of the water purification treatment is prevented. For example, when the ozone treatment is performed, it is possible to suppress the excessive injection of ozone and reduce the operating cost. In addition, since there is no shortage of ozone injection amount, stable ozone-treated water quality can be obtained.

In particular, continuous monitoring of the ozone treatment effect of musty odor substance (2MIB), which has been very difficult in the past, can be easily performed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a water purification device according to a first embodiment.

FIG. 2 is a graph showing a correlation between E260 residual ratio and ozone contact time.

FIG. 3 is a graph showing a correlation between a reaction rate constant and ηD.

FIG. 4 is a graph showing the correlation between the residual ratio of 2MIB and E260 and the ozone contact time.

FIG. 5 is a flowchart showing an ozone treatment method according to one embodiment of the present invention.

FIG. 6: THMFP and E2 in coagulation / ozone treatment system
The graph which shows the correlation with 60.

FIG. 7: THMFP and E2 in the coagulation / activated carbon treatment system
The graph which shows the correlation with 60.

FIG. 8 is an explanatory diagram of a UV meter.

FIG. 9 is an explanatory diagram of the water purification device according to the second embodiment.

[Explanation of symbols]

 1 ... Ozone treated water tank 2 ... Ozone processing tower 3 ... Ozonizer 4 ... Ozone treated water tank 5 ... Air diffuser 6 ... Gas phase ozone concentration meter 7 ... Control part

Claims (5)

[Claims] 1. The correlation between the absorbance of the test water and the concentration of the substance to be removed, the standard absorbance value corresponding to the standard concentration of the substance to be removed is calculated using the correlation, and the absorbance value of the test water after the water purification treatment is calculated. The water purification method is characterized in that the water purification treatment is performed so that the value becomes equal to or less than the specified absorbance value. 2. The water purification method according to claim 1, wherein the absorbance of the test water before the water purification treatment is detected, and the correlation between the progress of the water purification treatment and the absorbance of the water detection is obtained, and the correlation and the water purification treatment before the water purification treatment are performed. Using the absorbance value of the test water, control the progress degree of the water purification treatment by obtaining the prescribed progress degree of the water purification treatment required to make the absorbance value of the test water after the water purification treatment equal to or less than the prescribed absorbance value. A water purification method characterized in that 3. The water purification method according to claim 2, wherein ozone treatment is performed as the water purification treatment, and the ozone injection amount is used as the degree of progress of the water purification treatment, and the absorbance value of the test water after the water purification treatment is the specified absorbance value. A purified water treatment method characterized in that the ozone injection amount is controlled by a prescribed ozone injection amount required to achieve the following values. 4. The water purification method according to claim 2 or 3, wherein the absorbance of the test water after the water purification is calculated, and the absorbance is compared with the specified absorbance value to correct the progress of the water purification. A water purification method characterized in that 5. A water purification apparatus comprising an ozone treatment unit for removing a substance to be removed by an ozone treatment of injecting ozone into the test water, comprising a storage unit for a specified absorbance value of the test water and an ozone treatment unit before the ozone treatment. Measurement unit for absorbance of test water, correlation storage unit for storing correlation between ozone injection amount and absorbance of test water, absorbance value of test water before ozone treatment, and correlation obtained from the correlation storage unit And an ozone injection amount control unit for controlling the ozone injection amount by obtaining the ozone injection amount necessary for making the absorbance value of the test water after the ozone treatment equal to or less than the specified absorbance value. Water purification equipment.