JPH08215690A - Optimum ozone injection rate calculation apparatus and ozone injection control apparatus - Google Patents

Abstract

PURPOSE: To simply calculate an ozone amt. necessary for the reaction with an ozone consuming component in water to be treated with high accuracy by injecting ozone into water to be treated and comparison water prepared by removing an ozone consuming component from the water to be treated and measuring the difference between the concns. of dissolved ozone per a unit water amt. of both of them. CONSTITUTION: Water W to be treated is introduced into an ozone consuming component removing reaction tank 20 and ozone gas with predetermined concn. is injected into the reaction tank 20 from an ozonizer 2. The water to be treated and ozone are brought into contact with each other in the reaction tank 20 and treated water containing no ozone consuming component is introduced into a dissolved ozone removing reaction tank 25 and subsequently introduced into an ozone self-decomposing reaction tank 30. The amt. of waste ozone discharged to the open air from water is measured by a waste ozone concentration meter 32. The amt. of dissolved ozone contained in the water within the ozone self-decomposing reaction tank 30 is measured by a dissolved ozone concentration meter 35. Further, an ozone demand amt. is calculated on the basis of the difference between the amts. of dissolved ozone of both tanks 1, 30 in an ozone demand calculation part 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optimum ozone injection rate calculation device and an ozone injection control device used for ozone treatment of water to be treated at a water purification plant or a sewage treatment plant.

[0002]

2. Description of the Related Art Along with water pollution of water sources such as river water and lake water, water purification plants adopt an advanced water purification treatment method in which ozone is brought into contact with the sedimented water after coagulation and then biological activated carbon is treated. There is a tendency.

In the ozone treatment, water to be treated is introduced into an ozone contact tank to decolorize, deodorize, oxidize or denature organic substances in the water.

In the ozone treatment, it is required to efficiently treat the water to be treated with a minimum required ozone injection amount. For this reason, water amount proportional control in which ozone is injected at a constant injection rate proportional to the water amount is performed. However, water proportion control does not pose a problem if the concentration and composition of organic matter in the treated water introduced to the water treatment plant or sewage treatment plant is always constant. However, the concentration and composition of organic matter are seasonal factors, meteorological conditions, and even dam water. It changes greatly under the influence of external factors such as the release of fish, and is not always in a constant state. Therefore, the water volume proportional control is
When the water quality of the water to be treated changes, ozone is injected too little or too much, and there is a problem that the water quality after ozone injection processing becomes unstable.

From the above, the concentration of exhaust ozone discharged from the ozone contact tank to the gas phase after ozone injection is detected, and the ozone injection amount is controlled so that the ozone concentration becomes a constant value. Constant control was developed. Also,
A constant residual ozone concentration control has been developed which detects the dissolved ozone concentration remaining in the liquid phase in the ozone contact tank and controls the ozone injection amount so that the dissolved ozone concentration becomes a constant value. And the ozone injection amount control method which improved these methods was also developed. JP-A-4-197491 and JP-A-4-197491
Japanese Patent Publication No. 6-79290 describes an example of ozone injection rate control.

[0006]

Ozone injected into an ozone contact tank is consumed by reacting with ozone consuming components such as organic substances, and also self-decomposing, dissolving in water to be treated, or contacting ozone. It is discharged to the outside of the tank. The solubility of ozone in water and the self-decomposition in water change depending on the water temperature, pH, contact time, etc. of the water to be treated. For example, when the ozone-containing gas is brought into contact with water, the ozone concentration in the liquid can be expressed by the generally known empirical formula (1), but when the water temperature changes, the ozone concentration in the liquid also changes, and The solubility of ozone changes depending on the water temperature. The constant K in the equation (1) is based on a generally known empirical equation based on the relationship with the water temperature under atmospheric pressure.

C = K · Y (1) K = {0.604 × (1 + t / 273)} / 1 + 0.063
t where C: ozone concentration in liquid (g / m), K: constant,
t: Water temperature (° C), Y: Ozone concentration in air (g / m) On the other hand, the self-decomposition of ozone in liquid depends on pH and low p
With H, ozone self-decomposes slowly, but at high pH (alkaline side), the decomposition rate becomes faster. If the pH of the water to be treated changes, the concentration of dissolved ozone in the liquid will differ even if ozone is injected at the same injection rate. Therefore, even if the concentration and composition of organic substances in the water to be treated do not change and the ozone injection rate is constant, the concentration of exhausted ozone or the concentration of dissolved ozone is different, and it can be seen as a change in the concentration of organic substances.

Therefore, the feedback control based on the detected value of the exhaust ozone concentration or the dissolved ozone concentration cannot set the optimum ozone injection rate.

Originally, the ozone injection control may be performed by injecting an amount of ozone required by the water to be treated based on the required ozone amount obtained from the concentration of organic substances in the water to be treated. However, at present, there is no measuring instrument that can directly detect the amount of ozone injection required by the water to be treated online in a short time. As a result, it is difficult to control ozone injection with high control accuracy that corresponds to the water quality of the water to be treated and its change, and it is difficult to reduce running costs because ozone is injected excessively in consideration of operational safety. is there.

Therefore, the first object of the present invention is to easily increase the amount of ozone required to react with the ozone consuming component in the water to be treated (hereinafter referred to as the required ozone amount of the water to be treated). An object is to provide an optimum ozone injection rate calculation device that can be calculated with accuracy.

A second object of the present invention is to provide an ozone injection control device for controlling the ozone injection amount in ozone processing based on the ozone injection ratio calculated by the optimum ozone injection ratio calculation device.

A third object of the present invention is to provide an ozone treatment apparatus for water to be treated which is equipped with the above-mentioned optimum ozone injection rate calculation apparatus.

A fourth object of the present invention is to provide an ozone treatment method for performing ozone treatment based on the calculated optimum ozone injection rate.

[0014]

SUMMARY OF THE INVENTION A first object of the present invention is to:
Means for injecting ozone into treated water to be subjected to ozone treatment and comparative water obtained by removing ozone consuming components from the treated water so that the ozone injection rate per unit water amount is the same, and both of them are dissolved per unit water amount This is achieved by an optimum ozone injection rate calculation device, which comprises an ozone amount calculation means for measuring a difference in ozone concentration and using the difference as an ozone demand amount per unit amount of water to be treated.

As one mode of this optimum ozone injection rate calculation device, the same amount of treated water and comparative water are prepared, the same amount of ozone is injected into both, and the difference in the dissolved ozone concentration between the two is measured. It is desirable to provide an ozone amount calculation means for calculating the ozone demand amount per unit amount of water to be treated with a difference.

A second object of the present invention is an apparatus for controlling an ozone injection amount when injecting ozone into an ozone contact tank into which water to be treated has been introduced, which is equipped with the optimum ozone injection rate calculating apparatus, The ozone injection amount determining means for determining the ozone injection amount based on the ozone injection rate per unit amount of water calculated by the optimum ozone injection rate calculating device, and the ozone injection amount determined by the ozone injection amount determining means. And an ozone injection amount control means for controlling the amount of ozone injected into the ozone contact tank.

A third object of the present invention is to provide an ozone treatment apparatus comprising an ozone contact tank for bringing ozone into contact with water to be treated, and a means for injecting ozone into the ozone contact tank. An ozone injection amount determining means for determining an ozone injection amount based on the ozone injection rate per unit amount of water calculated by the optimum ozone injection rate calculating device, and an ozone injection determined by the ozone injection amount determining means. And an ozone injection amount control means for controlling the amount of ozone injected by the ozone injection means so that the amount of ozone becomes equal to the amount.

A fourth object of the present invention is to introduce ozone into the ozone contact tank by introducing the water to be treated into the contact tank, and perform ozone treatment in the ozone contact tank. Is obtained as described in the ozone injection control device, and the ozone amount thus obtained is injected into the ozone contact tank for ozone treatment. It

According to the present invention, when ozone is injected into the water to be treated containing the ozone consuming component and the comparative water obtained by removing the ozone consuming component from the water to be treated, the ozone injection amount is necessary for the reaction with the ozone consuming component. If it exceeds the ozone requirement,
Ozone consumption (self-decomposition amount of ozone and ozone demand amount) does not change, only the amount of discharged ozone and the amount of dissolved ozone change, and the amount of injected ozone is less than the amount required for reaction with ozone consuming components. For example, it was determined that the amount of ozone consumption (ozone self-decomposition amount and ozone demand amount) changes.

The ozone consumption amount Dg of the water to be treated is expressed by the following equation (2).
As shown in, the difference can be obtained by subtracting the dissolved ozone concentration in the water to be treated from the difference between the amount of ozone injected into the water to be treated and the amount of ozone discharged to the gas phase. Here, the ozone consumption amount Dg is an amount obtained by adding the ozone self-decomposition amount to the ozone required amount.

Dg = [{Qg (Cg1-Cg2)} / Qw] -Cw (2) Here, water amount: Qw (m ³ / h), injected ozone gas amount: Q
g (L / h), injected ozone gas concentration: Cg1 (mg /
L), ozone-containing exhaust gas concentration: Cg2 (mg / L), dissolved ozone concentration: Cw (mg / L), ozone consumption: Dg
(Mg / L) From these findings, the inventors of the present invention can treat the water to be treated by removing ozone consuming components from the water to be treated as the reference water and injecting ozone into the reference water. It has been found that no adjustment is necessary to match the water temperature or pH. That is, if the water to be treated from which ozone consuming components have been removed is used as the comparative water for determining the consumption amount due to the self-decomposition of ozone, the water temperature or pH of this comparative water substantially matches the treated water side. As a result, no means for adjusting the water temperature or pH is required, and there is no disturbing factor of ozone consumption associated with the pH adjustment, and it is possible to simply and accurately measure the ozone demand amount due to the oxidizable components in the water to be treated. it can.

Therefore, for the water to be treated containing the ozone consuming component that reacts with ozone, the amount of ozone that reacts with the ozone consuming component and the amount of ozone consumption due to self-decomposition of ozone are determined, and the ozone consuming component is further removed from the water to be treated. It is possible to inject ozone into the comparative water and the treated water, respectively, and obtain the ozone demand amount of the treated water from the difference in the dissolved ozone concentration between the comparative water and the treated water.

In the method of injecting ozone into the water to be treated to remove the oxidizable component, the strong oxidative power of ozone can efficiently oxidize and remove the oxidizable component which is an ozone consuming component. , The ozone consumption amount due to the self-decomposition of ozone cannot be determined accurately on the comparative water side only by not containing the oxidizable component.

That is, in the case where ozone is injected into the water to be treated to remove the ozone consuming component, and then this is used as comparison water, at the stage before the injection of ozone for self-decomposition,
Some ozone injected in the previous stage remains as dissolved ozone in the comparative water. In this case, this dissolved ozone concentration changes under the influence of the concentration of the ozone consuming component in the water to be treated, and if the concentration of the ozone consuming component is high, the injected ozone will be consumed by that amount, and therefore it will be a low value. On the other hand, if the concentration of the ozone consuming component in the water to be treated is low, the concentration of dissolved ozone will be high, and the concentration will not be constantly constant because it will decrease due to self-decomposition until the stage before the injection of ozone for self-decomposition. For this reason,
Next, when ozone is injected into comparative water containing dissolved ozone in order to determine the self-decomposition of ozone, the dissolved ozone concentration after the ozone injection changes under the influence of the above-mentioned residual dissolved ozone concentration.

Therefore, the dissolved ozone in the treated water after injecting ozone into the water to be treated is released to the gas phase by a removal means such as aeration, and then ozone is again injected as comparative water for obtaining the amount of self-decomposition of ozone. To do.

By using the above-mentioned method, it becomes possible to measure the ozone demand amount and the ozone self-decomposition amount for the ozone consuming component in the water to be treated containing the ozone consuming component, while the existing sensor measures the exhaust ozone amount and the ozone self decomposing amount. Since the dissolved ozone amount can be calculated, the consumption distribution of the ozone injection amount can be accurately measured.

As described above, the amount of ozone self-decomposition in the water to be treated containing consumable components depends on the water temperature and pH, but the ozone injection rate changes with the same water to be treated (same water temperature, pH). Even in the range of excess ozone) the amount of ozone used for self-decomposition of ozone does not change.

Further, the absolute amount of the consuming component per unit amount of water contained in the treated water containing the consuming component is the same in the case of the same treated water. Therefore, the ozone demand amount for the ozone consuming component in the same treated water is
It does not change even if the ozone injection rate changes (in the range of excessive ozone amount).

Accordingly, the present inventors have found that when ozone is injected in a range (excessive) in which sufficient reaction is performed with respect to the water to be treated, the ozone required amount is constant regardless of the injected ozone amount. I found that.

That is, in the ozone injection amount range, changes in the injected ozone amount increase or decrease the exhaust ozone amount and the dissolved ozone amount, and do not affect the ozone demand amount.

On the other hand, when the amount of ozone injected into the water to be treated is insufficient for the reaction with the ozone consuming component (insufficient), the reaction rate of the consuming component with respect to ozone is slower than the self-decomposition rate of ozone. In this case, most of the ozone is consumed for the self-decomposition, the ozone consuming component becomes difficult to react with sufficient ozone, and the ozone demand is apparently reduced, or the reaction rate of the consuming component to ozone is calculated. It was found that when ozone is faster than the self-decomposition rate of ozone, most of the ozone is used for the reaction with the consumption component, and the apparent self-decomposition amount of ozone is calculated to be small.

Therefore, the feature of the present invention is that the ozone demand amount when the ozone demand amount is calculated by the above-mentioned method by injecting different ozone amounts into the same water to be treated, and The optimum ozone injection rate for the water to be treated can be calculated by calculating a small ozone injection rate.

As a preferred embodiment of the present invention, the ozone injection amount at the time of ozone injection control in the advanced water purification treatment in the water purification plant is the ozone required for the reaction with the ozone consuming component in the water to be treated, which is obtained as described above. The optimum amount of ozone injection is calculated and controlled by paying attention to the amount, that is, the required ozone amount. As a result, even if the water quality of the water to be treated fluctuates, ozone can be injected into the water to be treated by grasping the required ozone amount of the water to be treated in advance. Become.

[0034]

When measuring the ozone demand of the water to be treated, ozone is injected into the water to be treated and the comparative water after removing the ozone consuming components in the water to be treated, and the water to be treated after the ozone is injected. Since the ozone required amount of the treated water is obtained from the difference in the dissolved ozone concentration between the treated water and the comparative water, it is possible to easily measure the ozone required amount of the treated water with high accuracy.

Further, when the ozone demand amount of the water to be treated is calculated, the ozone demand amount of the water to be treated is calculated based on the result of the ozone injection treatment of the water to be treated. It is possible to calculate the ozone demand amount that reflects the plan and characteristics of.

Further, during the ozone injection control of the advanced water treatment at the water purification plant, the ozone injection amount is controlled on the basis of the required ozone amount of the treated water to be treated, so that it is possible to cope with the water quality fluctuation of the treated water. Ozone can be injected.
As a result, even if the water quality of the water to be treated changes, stable ozone injection processing becomes possible, and the water quality after ozone injection can be stabilized.

[0037]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the system flow of the ozone demand measuring device for the water to be treated. The ozone demand measuring device of this embodiment is roughly classified into a part for purifying comparative water for calculating the amount of self-decomposition of ozone and a part for performing an ozone reaction with respect to actual water to be treated.

First, the procedure for purifying comparative water will be described. First, treated water W is a reaction tank 2 for removing ozone consuming components
Introduce to 0. Ozone gas having a predetermined concentration (ozone concentration sufficient to remove the ozone consuming component) is injected from the ozonizer 2 into the ozone consuming component removing reaction tank 20.

A dehumidifier 3 arranged on the inlet side of the ozonizer 2 removes moisture in the raw material gas G (air or oxygen) supplied to the ozonizer 2, and the dry raw material gas having a low dew point is used as the ozonizer 2. Supply to. In one embodiment of the invention,
Air as a raw material gas G is supplied to the ozonizer 2 by the air pump 5 via the filter 4.

Ozone from the ozonizer 2 is controlled in the ozone concentration generated by the ozonizer controller 6. In this embodiment, the generated ozone concentration is controlled by adjusting the voltage applied to the discharge part of the ozonizer 2.

The flow rate of ozone injected into the ozone consuming component removing reaction tank 20 is adjusted by a flow rate adjusting valve 21,
Ozone set to a predetermined flow rate is injected into the ozone consuming component removing reaction tank (hereinafter, simply referred to as reaction tank) 20.

The water W to be treated is sampled by the sampling pump 10 and introduced into the reaction tank 20 through the flow rate adjusting valve 22.

The treated water and the injected ozone come into contact with each other in the reaction tank 20, the ozone consuming component of the treated water is removed by the ozone contact reaction, and the treated water containing no ozone consuming component is used for removing dissolved ozone. It is introduced into the reaction tank 25.

Since the treated water introduced into the reaction tank 25 contains an excessive amount of dissolved ozone, the air from the air pump 5 is introduced into the reaction tank 25 via the flow rate adjusting valve 26 for the purpose of removing the dissolved ozone. Introduce and bubbling (aeration). As a result, the dissolved ozone in the treated water introduced into the reaction tank 25 is released from the liquid phase to the gas phase, and the dissolved ozone is removed.

The treated water TW from which the ozone consuming component and the excess dissolved ozone are removed in this way is introduced into the ozone self-decomposition reaction tank 30 arranged on the downstream side through the flow rate adjusting valve 31.

On the other hand, the water W to be treated is collected by the sampling pump 1
After being sampled at 0, it is introduced into the reaction tank 1 via the flow rate adjusting valve 8.

When the treated water TW is introduced into the self-decomposition reaction tank 30 and the water to be treated W is introduced into the ozone reaction tank 1, the same amount of ozone is injected into each reaction tank, and after a certain time ( After the ozone contact time of the actual plant has elapsed), the dissolved ozone concentration in each reaction tank is measured, and the ozone demand amount and the amount of self-decomposition of ozone relative to the ozone consumption component amount are calculated from the difference in the dissolved ozone concentration. The amount of ozone injected into the ozone reaction tank 1 is controlled by the flow rate adjusting valve 7.

Calculation of the required ozone amount and the self-decomposition amount of ozone will be described with reference to FIG.

First, ozone is injected into the ozone self-decomposition reaction tank into which the treated water TW is introduced, and the ozone consumption distribution with respect to the total amount of injected ozone when ozone is contacted for a certain time is shown in FIG. As shown in 30.

Part of the injected ozone is discharged from the liquid into the air as exhaust ozone. The amount of exhaust ozone is measured by the exhaust ozone concentration meter 32 shown in FIG. The amount of dissolved ozone contained in the liquid in the ozone self-decomposition reaction tank 30 is measured by the dissolved ozone concentration meter 35. Then, the ozone amount obtained by subtracting the above-mentioned exhausted ozone amount and dissolved ozone amount from the total ozone amount injected into the ozone self-decomposition reaction tank 30 becomes the ozone self-decomposition amount in the treated water TW.

On the other hand, the ozone consumption distribution to the total ozone injection amount at the time when ozone is injected into the ozone reaction tank into which the water to be treated W is introduced and the ozone contact is made for a certain time is shown in the ozone reaction tank 1 of FIG. Like The water to be treated W introduced into the ozone reaction tank 1 has the same water temperature, pH, ozone injection amount, and ozone contact time as the treated water TW introduced into the ozone self-decomposition reaction tank 30. The amount of discharged ozone and the amount of self-decomposition of ozone in the tank 1 and the ozone self-decomposition reaction tank 30 are the same. However, ozone reaction tank 1
Since the water W to be treated, which is introduced into, contains ozone consuming components, part of the dissolved ozone measured in the ozone self-decomposition reaction tank 30 is consumed as ozone consuming components in the ozone reaction tank 1. The remaining portion is measured as the amount of dissolved ozone by the dissolved ozone concentration meter 9. Reference numeral 11 indicates an exhaust ozone concentration meter.

As described above, since the difference in the amount of dissolved ozone in the ozone reaction tank 1 and the ozone self-decomposition reaction tank 30 is the amount of ozone consumed by the ozone consuming component, the ozone demand measuring device of FIG. By using, it becomes possible for the ozone demand amount calculation unit 40 to calculate the ozone demand amount.

Calculate the ozone demand based on the present invention,
An example of calculating the optimum ozone injection rate will be described below.

As described above, the absolute amount of the consuming component per unit amount of water contained in the treated water containing the consuming component is the same for the same treated water. Therefore, the ozone demand amount for the ozone consuming component in the same water to be treated does not change even if the ozone injection rate changes in a range where the ozone injection amount is excessive.

Accordingly, the present inventors have found that when ozone is injected in a range (excessive) in which the water to be treated is sufficiently reacted, the required ozone amount is constant regardless of the injected ozone amount. I found a thing. That is, if the total ozone amount is in the range shown by TO1 to TO4 in FIG. 3, the ozone demand amount is constant regardless of the injected ozone amount. That is,
In the ozone injection amount range, the change of the injected ozone amount shows the increase and decrease of the exhaust ozone amount and the dissolved ozone amount, and does not affect the ozone demand amount.

On the other hand, when the amount of ozone injected into the water to be treated is insufficient (insufficient) for the reaction with the ozone consuming components, the reaction is sufficiently performed (excess) in the water to be treated. Either the self-decomposition amount of ozone or the required ozone amount is apparently less than that when ozone is injected in.

Focusing on the self-decomposition of ozone and the ozone reaction rate with respect to ozone-consuming components, the phenomenon in which either the ozone self-decomposition amount or the ozone demand amount is apparently reduced will be described in detail.

First, when the amount of ozone injected into the water to be treated is insufficient (insufficient) for the reaction with the ozone consuming component, and the reaction rate of the consuming component with respect to ozone is slower than the self decomposition rate of ozone, A phenomenon in which the ozone demand amount is apparently reduced to be calculated will be described with reference to FIG.

When the reaction rate of the consumption component with respect to ozone is slower than the self-decomposition rate of ozone, most of the ozone is consumed for self-decomposition. When the amount of ozone injected into the water to be treated is insufficient in the reaction with the ozone consuming component, it becomes difficult for the ozone consuming component to react with sufficient ozone, and the apparent ozone demand is as shown in FIG. As can be seen in TO5, it is calculated to be smaller than TO1 to TO4. That is, in the example shown in FIG. 4, the ozone injection amount TO4
Is the most economical (smallest) injection amount in which the ozone consuming component and ozone sufficiently react, and is calculated as the optimum ozone injection rate.

Next, when the amount of ozone injected into the water to be treated is insufficient (insufficient) for the reaction with the ozone consuming component, and the reaction rate of the consuming component with respect to ozone is faster than the self-decomposition rate of ozone, A phenomenon in which the amount of self-decomposition of ozone is apparently reduced will be described with reference to FIG.

When the reaction rate of the consuming component with respect to ozone is faster than the self-decomposing rate of ozone, most of the ozone is used for the reaction with the consuming component, and the apparent self-decomposing amount of ozone is TO5 and TO5 in FIG. As in the case of TO6, TO1
It is calculated to be smaller than to TO4. In the TO5 example, there is still sufficient total ozone injection to react with the ozone consuming components. However, the total ozone injection amount is TO5
With a smaller TO6, the injected ozone amount becomes insufficient in the reaction with the ozone consuming component, and the apparent ozone demand amount is calculated to be smaller than that of TO1 to TO5. That is, the ozone injection amount TO5 in FIG.
Is the most economical (smallest) injection amount in which the ozone consuming component and ozone sufficiently react, and is calculated as the optimum ozone injection rate.

Therefore, the feature of the present invention is that the ozone demand amount when the ozone demand amount is calculated by the above-mentioned method by injecting different ozone amounts into the same water to be treated does not decrease and is as much as possible. The optimum ozone injection rate for the water to be treated can be calculated by calculating the small ozone injection rate.

An embodiment of the ozone injection rate calculation device for calculating the optimum ozone injection rate will be described with reference to the system flow of FIG.

The reaction tanks 50, 60, 70, 80, 9 shown in FIG.
Reference numeral 0 is a device for calculating the required ozone amount in the same form, and each of them is the reaction tank 1, 20, 2 previously shown in FIG.
It is an apparatus including 5, 30 and the like and capable of calculating the required ozone amount DK by injecting the water W to be treated and ozone of a predetermined concentration.

The flow rates of ozone injected into the reaction tanks 50, 60, 70, 80 and 90 are the flow valves 52 and 6, respectively.
2, 72, 82, and 92, and ozone of different flow rate is injected into each reaction tank. The total ozone injection amount into the reaction tank 50 is set to TO1, and similarly, the total ozone injection amount into the reaction tank 60 is TO2, the total ozone injection amount into the reaction tank 70 is TO3, and the total ozone injection amount into the reaction tank 80 is the same. The amount is set to TO4, and the total amount of ozone injected into the reaction tank 90 is set to TO5.

Ozone demand amounts DK1, DK2, DK for the respective ozone injection amounts in the calculation units in the respective reaction tanks.
3, DK4, DK5 are calculated.

FIG. 7 shows the relationship between the total ozone injection amount TO and the ozone demand amount DK of the optimum ozone demand amount calculating apparatus of FIG.

As described in the example of FIG. 3, when a sufficient amount of ozone is injected for the reaction with the ozone consuming component (examples of TO1 to TO4), the required ozone amount DK of FIG.
1 to DK4, there is no change in the ozone demand amount, and if the ozone injection amount is insufficient for the reaction with the ozone consuming component, the ozone demand amount is apparently reduced and calculated. This does not mean that the ozone consuming component is low,
This is because the amount of ozone that is sufficient for the ozone consuming components to react is not injected.

That is, in order to calculate the optimum ozone injection rate for sufficiently reacting ozone consuming components, the same treated water W is supplied to an apparatus having a plurality of ozone reaction tanks of the same form as shown in FIG. By introducing water and injecting ozone with different ozone injection amounts into the respective reaction tanks, the ozone injection amount (TO1 to TO1 that effectively reacts with the ozone consuming component without decreasing the amount of ozone necessary to react with the ozone consuming component). (TO4)
In addition, the optimum ozone injection rate calculation unit 120 can calculate the ozone injection amount at the limit point (TO4) where the total ozone injection amount is the smallest.

An embodiment of the optimum ozone required amount calculating method for obtaining the same effect as the optimum ozone injection rate calculating device shown in FIG. 6 by using the ozone required amount measuring device shown in FIG. 1 will be described.

In the ozone demand measuring device of FIG. 1, when the treated water TW and the water to be treated W are introduced into the respective reaction tanks (the ozone self-decomposition reaction tank 30 and the reaction tank 1), the reaction water is supplied to the respective reaction tanks. After injecting the same amount of ozone, measure the dissolved ozone concentration in each reaction tank after a certain time (such as the ozone contact time of the actual plant), and calculate the required ozone amount for the ozone consumption component amount from the difference in the dissolved ozone concentration. calculate.

Here, it is possible to obtain the same effect as that of the optimum ozone injection rate calculation device shown in FIG. 6 by changing the amount of ozone injected into each reaction tank stepwise.

A method for calculating the optimum ozone injection rate using the ozone demand amount measuring apparatus of FIG. 1 will be specifically described with reference to an embodiment of total ozone injection amount and ozone demand amount shown in FIG. As a first step, the total ozone injection amount TO1 is injected into the ozone reaction tank 1 and the ozone self-decomposition reaction tank 30 in the ozone demand measuring device of FIG. The ozone demand amount DK calculated at this time is calculated as DK1.

As the second step, the ozone demand amount DK calculated when the total ozone injection amount TO2 is injected into the ozone reaction tank 1 and the ozone self-decomposition reaction tank 30 in the ozone demand amount measuring device of FIG. 1 is calculated as DK2. To be done.

In the same manner, the total ozone injection amount TO3,
The ozone demand amount DK calculated when TO4 and TO5 are injected is calculated as DK3, DK4, and DK5, respectively.

As described above, the total ozone injection amount TO into the ozone reaction tank 1 and the ozone self-decomposition reaction tank 30 is changed stepwise, and the ozone demand amount DK with respect to the total ozone injection amount into the reaction tank is calculated at any time. This makes it possible to calculate the relationship as shown in FIG.

In order to calculate the optimum ozone injection rate for sufficiently reacting the ozone consuming component with ozone, the same treated water W is introduced into the ozone demand measuring device shown in FIG. By gradually injecting different ozone injection amounts into the ozone, the required ozone amount that reacts with the ozone consuming component does not decrease, and the ozone injection amount that effectively reacts with the ozone consuming component (TO1 to TO4) is the most total ozone injection. The ozone injection amount at the limit point (TO4) where the amount is small can be calculated.

According to this method, the time for calculating the optimum ozone injection rate is longer than that of the apparatus shown in FIG. 6, but in terms of hardware, the ozone demand measuring apparatus shown in FIG. 1 is used. The optimum ozone injection rate can be calculated, which has the advantage that the device is simple and inexpensive.

[0079]

According to the present invention, it is possible to calculate the minimum ozone injection rate with a necessary ozone amount sufficient to react with the ozone consuming component in the water to be treated which is the object of ozone injection treatment. Therefore, when injecting ozone into the water to be treated, optimal ozone injection control can be performed based on the amount of ozone required to react with the ozone consuming component.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an ozone demand measuring device.

FIG. 2 is a diagram showing consumption distribution of total ozone injection amount.

FIG. 3 is an explanatory diagram showing changes in the required ozone amount according to the ozone injection rate of the present invention.

FIG. 4 is an explanatory diagram showing a change in an ozone required amount depending on an ozone injection rate when an ozone self-decomposition reaction rate is faster than a reaction rate with an ozone consuming component.

FIG. 5 is an explanatory diagram showing a change in an ozone required amount depending on an ozone injection rate when an ozone self-decomposition reaction rate is slower than a reaction rate with an ozone consuming component.

FIG. 6 is a schematic diagram of an optimum ozone injection rate calculation device.

FIG. 7 is an explanatory diagram showing the relationship between the total ozone injection rate and the required ozone amount.

FIG. 8 is an explanatory diagram showing the relationship between the total ozone injection rate and the required ozone amount.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ozone reaction tank, 2 ... Ozonizer, 5 ... Air pump, 6 ... Ozonizer controller, 9,35 ... Dissolved ozone concentration meter, 11, 32 ... Exhaust ozone concentration meter, 20 ... Reaction tank for removing ozone consuming components, 25 ... Reaction tank for removing dissolved ozone, 30
… Ozone self-decomposition reaction tank, 40… Ozone demand calculation unit,
120 ... Optimal ozone injection rate calculation unit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Naoki Hara 5-2-1 Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Omika factory

Claims (7)

[Claims] 1. A means for injecting ozone so that the treated water to be subjected to ozone treatment and the comparative water obtained by removing ozone consuming components from the treated water have the same ozone injection rate per unit amount of water, and both. An optimum ozone injection rate calculation device comprising: an ozone amount calculation means for measuring a difference in dissolved ozone concentration per unit amount of water, and using the difference as an ozone required amount per unit water amount of water to be treated. 2. The ozone injection means for preparing the same amount of the treated water and the comparative water, and injecting the same amount of ozone into each of the treated water and the difference between the dissolved ozone concentrations thereof according to claim 1. An optimal ozone injection rate calculation device, comprising: an ozone amount calculation means for determining the ozone demand amount per unit amount of water to be treated by the difference. 3. An apparatus for controlling an ozone injection amount when injecting ozone into an ozone contact tank into which treated water is introduced, the treated water, and comparative water obtained by removing ozone consuming components from the treated water. And the means for injecting ozone so that the ozone injection rate per unit amount of water is the same, and the difference in the dissolved ozone concentration per unit amount of water between the two is measured, and the difference is used as the required ozone amount per unit amount of treated water. An ozone injection amount determining means for determining the ozone injection amount based on the ozone injection rate per unit water amount calculated by the optimum ozone injection rate calculating device. And an ozone injection amount control means for controlling the amount of ozone injected into the ozone contact tank so that the ozone injection amount is determined by the ozone injection amount determining means. Ozone injection control device that. 4. An ozone treatment apparatus comprising an ozone contact tank for causing a contact reaction between water to be treated and ozone, and a means for injecting ozone into the ozone contact tank, the water to be treated and the water to be treated. A method of injecting ozone so that the ozone injection rate per unit amount of water is the same as that of the comparative water from which ozone consuming components have been removed, and the difference in the dissolved ozone concentration per unit amount of water between the two is measured, and the difference is measured An optimum ozone injection rate calculating device having an ozone amount calculating means for determining an ozone demand amount per unit water amount, and further ozone injection based on the ozone injection rate per unit water amount calculated by the optimum ozone injection rate calculating device. Ozone injection amount determining means for determining the amount, and ozone for controlling the amount of ozone injected by the ozone injecting means so that the ozone injection amount is determined by the ozone injection amount determining means. Ozone treatment apparatus, comprising the Iriryou control means. 5. A method in which treated water is introduced into an ozone contact tank, ozone is injected into the contact tank to perform ozone treatment, and a comparison is made between the treated water and an ozone consuming component from the treated water. The process of preparing water and injecting ozone so that the ozone injection rate per unit amount of water is the same, measuring the difference in the dissolved ozone concentration per unit amount of both water, and measuring the difference between A step of determining an ozone required amount, a step of determining an ozone injection amount based on the ozone injection rate per unit water amount calculated in the step, and the ozone contact tank having the ozone injection amount determined in the step An ozone treatment method comprising the step of controlling the amount of injected ozone. 6. A means for injecting ozone so that the treated water to be treated with ozone and the comparative water obtained by removing ozone consuming components from the treated water have the same ozone injection rate per unit amount of water, and a means for injecting ozone. A plurality of ozone demand amount calculation devices having an ozone amount calculation means for measuring the difference in the dissolved ozone concentration per unit amount of water and setting the difference as the ozone demand amount per unit amount of water to be treated are installed in parallel, and The same water to be treated is introduced into each of the ozone demand calculation devices, and ozone with different ozone injection rates is injected, and the ozone demand is the maximum among the ozone demands calculated by the ozone demand calculation device. An optimum ozone injection rate calculation method is characterized in that the ozone injection rate of the ozone required amount calculating device that minimizes the ozone injection rate is set as the optimum ozone injection rate. 7. The ozone demand amount according to claim 6, wherein the injection rate of ozone to be injected into the plurality of ozone demand amount calculation devices is changed stepwise at fixed time intervals, and the ozone demand amount is calculated at any time. The optimum ozone injection rate calculation method is characterized in that the ozone injection rate of the ozone demand amount calculating device having the maximum value and the minimum ozone injection rate is set as the optimum ozone injection rate at that time.