JPH0326393A - Water treating device - Google Patents

Abstract

PURPOSE:To oxidize org. matter having no unsaturated bonds with ozone by providing a pipe for introducing water to be treated, an ozone diffuser pipe, a catalyst diffuser pipe and a mechanism for circulating the catalyst settled on the bottom in an ozone reaction vessel. CONSTITUTION:Water A to be treated is introduced into the ozone reaction vessel 1 through an inlet pipe 2, and an ozone-contg. gas B is injected into the water A as bubbles from the diffuser pipe 5 through an inlet pipe 4. The gas B is subjected to a gas-liq. catalytic reaction with the water A and sent upward to the upper part of the vessel 1, and the ozone is dissolved in the water to oxidize the org. matter in the water. Meanwhile, ferric oxide C as catalyst is uniformly injected into the water A from the diffuser pipe 7 at the upper part and gravitated in the water, and the ozone oxidation reaction is accelerated. The catalyst settled on the bottom of the vessel is returned to the diffuser pipe by a circulating mechanism and effective used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a water treatment device that purifies contaminated water using ozone.

(Prior art) Conventionally, for example, for the purpose of sterilizing tap water, for the purpose of decolorization in wastewater treatment of human waste treatment facilities, and for the purpose of oxidation treatment of organic substances in industrial water and special water,
Water treatment equipment that utilizes the oxidizing power of ozone is used.

In general, ozone is produced by silent discharge against air or oxygen, and is obtained as an ozone-containing substance.In conventional water treatment equipment, fine ozone-containing substances are injected into a septic tank for water to be treated from the bottom of the tank. By causing a gas-liquid contact reaction between ozone and the water to be treated, the ozone in the bubbles rising in the water oxidizes the pollutants in the water to be treated. In this case, ozone gas is used to oxidize organic substances dissolved in water from air bubbles, and the reaction with unsaturated bonded organic substances such as coloring components is particularly fast, so the decolorizing effect is extremely high. However, little effect was seen on organic substances that do not have unsaturated bonds.

(Problems to be Solved by the Invention) As described above, in conventional water treatment equipment that uses only the gas-liquid contact reaction between ozone and water to be treated, there is insufficient ozone for organic substances that do not have unsaturated bonds. Because it could not perform oxidation treatment, it was unsuitable for purifying contaminated water containing dissolved organic substances that do not have these unsaturated bonds.

Therefore, the present invention can promote ozone oxidation treatment of organic substances that do not have unsaturated bonds by simply adding a relatively simple and inexpensive configuration, and can also purify contaminated water in which organic substances that do not have unsaturated bonds are dissolved. The aim is to provide a water treatment device that can perform water treatment reliably.

[Structure of the Invention] (Means for Solving the Problems) The water treatment apparatus of the present invention includes an ozone reaction tank in which ozone and water to be treated undergo a gas-liquid contact reaction, and a water to be treated is introduced into the reaction tank. An ozone diffuser pipe that injects ozone-containing gas into the water to be treated from the lower part of the reaction tank, a catalyst watering pipe that disperses and injects the catalyst into the water to be treated from the upper part of the reaction tank, and It is equipped with a circulation mechanism that circulates the catalyst precipitated at the bottom to the water spray pipe.

Iron oxide can be considered as the catalyst that is dispersed and injected through the catalyst watering pipe.

Further, it is desirable that the bottom of the ozone reaction tank be formed into a tapered shape.

(Function) In a water treatment device with such a configuration, ozone-containing gas is injected from the lower part of the ozone reaction tank into which the water to be treated is introduced through the introduction pipe, and the water to be treated is introduced from the upper part of the reaction tank. Catalyst is dispersed and injected through a water sprinkler pipe.

As a result, an oxidation reaction occurs in the reaction tank due to a gas-liquid contact reaction between ozone and the water to be treated, and this ozone oxidation reaction is promoted by the catalyst.

On the other hand, the catalyst injected into the water to be treated settles at the bottom of the reaction tank, but this precipitated catalyst is returned to the water sprinkler pipe by the circulation mechanism and is effectively used.

After conducting various investigations as a catalyst for promoting the ozone oxidation reaction, it was found that iron oxide is preferable. This may be due to organic matter adhering to the iron oxide surface, making it susceptible to the ozone oxidation reaction, or iron oxide decomposing intermediate products such as peroxide and hydrogen peroxide produced by the reaction between ozone and organic matter. This is considered to be a promotion.

Below, an experimental example will be shown to prove that iron oxide is suitable as a catalyst.

*Experimental Example I Malonic acid C H 2 ( C O OH ) '2
The following experiment was conducted using the dissolved organic matter. That is, first, 220 ml of malonic acid aqueous solution with a COD (chemical oxygen demand) of 42 mg/j and a water temperature of 25°C was put into a 250 ml air washing bottle, and the ozone concentration was 8 ag/j.
COD by diffusing j of ozonized air at a rate of 1p per minute.
We calculated the change over time. The experimental results in this case are shown in 5A in FIG.

Next, similar ozone treatment was carried out by suspending 2,0g of ferric oxide in the same malonic acid aqueous solution. The experimental results in this case are shown in B in FIG.

As is clear from Figure 2, the COD removal rate after 30 minutes was 19% higher in the product containing iron oxide (experimental result B) than in the product containing no iron oxide (experimental result A). ．．
0% rose to 33.3%, and after 1 hour, 23.8% rose to 57.8%. From the above experimental results, iron oxide promotes the ozone oxidation reaction against malonic acid aqueous solution. I understand that.

*Experiment example■ As actual sewage water, tertiary treatment was performed by injecting 9 mg/1 polyaluminum chloride as a coagulant into secondary treated sewage water, which was mainly domestic wastewater and treated with activated sludge method to remove dirt, and filtered with sand. The following experiment was conducted using water. In addition, the experimental method was that the malonic acid aqueous solution in Experimental Example I was replaced with tertiary treated water, and other methods were used. All experimental conditions were the same.

6 The results of an experiment conducted without mixing ferric oxide are shown in FIG. 3A, and the results of an experiment conducted with ferric oxide suspended are shown in FIG. 3B. Also in this case, the one mixed with iron oxide (experimental result B)
The COD removal rate was 20.0% after 30 minutes compared to the one without iron oxide (experimental result A).
．． It rose to 0% and after 1 hour it was 28.0% to 56.0%
The above experimental results indicate that iron oxide promotes the ozone oxidation reaction in treated sewage water.

(Example) FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention.

In the figure, 1 is an ozone reaction tank for causing a gas-liquid contact reaction between ozone and water to be treated, and this ozone reaction tank 1
A treated water introduction pipe 2 for introducing treated water A is connected to the upper side of the tank, and a treated water discharge pipe 3 for discharging the treated water treated in this reaction tank 1 is connected to the lower side of the tank. has been done.

Further, an ozone diffuser pipe 5 is provided at the lower part of the ozone reaction tank 1 to inject ozone-containing gas B generated by an ozone generator (not shown) and supplied via an ozone introduction pipe 4. An ozone discharge pipe 6 is connected to the upper surface of the reaction vessel 1 for discharging unreacted ozone-containing gas B within the reaction vessel 1 .

Further, a catalyst water sprinkling pipe 7 is disposed in the upper part of the ozone reaction tank 1 for uniformly dispersing and injecting ferric oxide C as a catalyst for promoting the ozone oxidation reaction into the water to be treated. 7 is connected to a supply tank 8 filled with the ferric oxide C via a valve 9. Further, the bottom of the ozone reaction tank 1 is formed in a tapered shape, which facilitates the accumulation of ferric oxide C, which is injected into the water to be treated from the sprinkler pipe 7 and naturally settles as a catalyst. A circulation pump 11 draws out the ferric oxide C accumulated at the bottom in the form of slurry and circulates it to the water sprinkling pipe 7 via the return pipe 10.
is provided. That is, the circulation pump 11 and the return pipe 10 constitute a circulation mechanism. Further, a filter 12 is attached to the treated water inlet of the treated water discharge pipe 3 to prevent the ferric oxide C from flowing in together with the treated water.

In the water treatment apparatus of this embodiment configured as described above, first, water A to be treated such as sewage water is introduced into the ozone reaction tank 1 through the introduction pipe 2. Next, the ozone-containing gas B produced by the ozone generator is injected into the water A to be treated as bubbles through the introduction pipe 4 and the aeration pipe 5. Then, the ozone-containing gas B injected as bubbles through the aeration pipe 5 rises to the top of the reaction tank 1 while performing a gas-liquid contact reaction with the water to be treated A, but at this time, the ozone-containing gas B is dissolved from the bubbles into the water to be treated. The organic matter dissolved in the water to be treated is oxidized.

On the other hand, ferric oxide C as a catalyst is also uniformly dispersed and injected into the water A to be treated from above through the water sprinkler pipe 7. Here, ferric oxide C is injected in advance from the supply tank 8 in an amount commensurate with the amount of water to be treated to be introduced, and naturally settles in the treated water. Then, the second oxide layer is accumulated at the bottom portion formed in a tapered shape.
Iron C is extracted in the form of a slurry together with the treated water in the ozone reaction tank 1 by the circulation pump 11, guided through the return pipe 10 to the sprinkler pipe 7, and uniformly dispersed and injected into the water to be treated A again. Ru. This process of circulating ferric oxide C is repeated, and if it accumulates at the bottom of the reaction tank 1 or inside the pipes and the content of ferric oxide in the water to be treated decreases, it is replenished from the replenishment tank 8. be done.

As is clear from the above-mentioned experimental results, by injecting ferric oxide C as a catalyst into the ozone reaction tank 1 in which the water to be treated and ozone undergo a gas-liquid contact reaction, unsaturation dissolved in the water to be treated can be reduced. The ozone oxidation reaction is promoted not only for organic substances that have bonds but also for organic substances that do not have unsaturated bonds. Therefore, even if organic substances having no unsaturated bonds are dissolved in the water to be treated A, purification by the ozone oxidation reaction is reliably performed, and the treated water is discharged to the outside through the discharge pipe 3. At this time, since the ferric oxide C contained in the treated water is prevented from being discharged by the filter 12, there is no problem. Note that the ozone-containing gas B that was not used in the ozone oxidation reaction in the ozone reaction tank 1 is led to an ozone decomposition device (not shown) through a discharge pipe 6, where it is decomposed into ozone and rendered harmless (10), and then discharged into the atmosphere. Ru.

In this way, the water sprinkler pipe 7, supply tank 8, To reliably purify treated water containing dissolved organic matter having no unsaturated bonds with a simple and relatively inexpensive configuration that only includes a valve 9, a circulation pump 11 as a circulation mechanism, and a return pipe 10. You will be able to do this.

Further, since the bottom of the ozone reaction tank 1 is formed into a tapered shape, the naturally precipitated ferric oxide C can be accumulated without being deposited on the bottom surface, and the ferric oxide can be used effectively.

It goes without saying that the present invention is applicable not only to sewage treatment, but also to industrial wastewater, special wastewater, human waste treatment, water purification treatment using contaminated surface water, and the like.

[Effects of the Invention] As described in detail above, according to the present invention, ozone oxidation treatment for organic substances that do not have unsaturated bonds can be promoted by simply adding a comparatively simple and inexpensive structure, and this unsaturated It is possible to provide a water treatment device that can reliably purify contaminated water in which unbonded organic matter is dissolved.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of an embodiment of the present invention, and FIGS. 2 and 3 are characteristic diagrams showing the results of experiments conducted to explain the principle of the present invention. 1...Ozone reaction tank, 2...Water to be treated introduction pipe, 3.
... Treated water discharge pipe, 4 ... Ozone introduction pipe, 5 ... Ozone diffuser pipe, 6 ... Ozone discharge pipe, 7 ... Catalyst watering pipe, 8 ... Ferric oxide supply tank, 9...Valve, 10
...Return pipe, 11...Circulation pump, 12...Filter, A...Water to be treated, B...Ozone-containing gas, C
...Ferric oxide.

Claims (3)

[Claims] (1) An ozone reaction tank in which ozone and water to be treated undergo a gas-liquid contact reaction, a water introduction pipe to introduce the water to be treated into the reaction tank, and an ozone-containing gas introduced from the lower part of the reaction tank. An ozone diffuser pipe for injecting into the water to be treated, a catalyst watering pipe for distributing and injecting a catalyst into the water to be treated from the top of the reaction tank, and circulating the catalyst precipitated at the bottom of the reaction tank to the watering pipe. A water treatment device characterized by comprising a circulation mechanism. (2) The water treatment device according to claim 1, wherein the catalyst dispersed and injected through the catalyst watering pipe is iron oxide. (3) The water treatment apparatus according to claim 1, wherein the ozone reaction tank has a tapered bottom.