JPH03143594A - Water treatment - Google Patents

Abstract

PURPOSE:To allow the sure ozone oxidation of even the dissolved org. matter which has no unsaturation bonds and to improve the efficiency of a treatment with ozone by passing water which is to be treated and in which ozone reaction accelerating media (catalysts) are suspended through the packing material of an ozone reaction chamber. CONSTITUTION:The water which is to be treated and is introduced from an introducing pipe 20 for the water to be treated in a mixing tank 19 and the iron oxide 16 of the ozone reaction accelerating media (catalysts) withdrawn from a withdrawing valve 18 are mixed and the mixture is sprayed onto the packing material 12 in the ozone reaction chamber 11 by a slurry pump 21. An ozone-contg. gas is diffused into the ozone reaction chamber 11 from an air diffusing pipe 14 in the bottom of the reaction chamber via an ozone-contg. gas introducing piping 13 and rises to the upper part while making gas-liquid contact with the slurry water to be treated flowing down in the packing material 12. This gas is released to the atm. through an ozone decomposing device 23. The treated water is stored in a separating tank 15 where the iron oxide 16 is settled by gravity. The treated water is taken out of a treated water outflow pipe 17 to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in a water treatment method for purifying contaminated water with ozone.

(Prior Art) Ozone is usually produced as an ozone-containing substance by the silent discharge action of air or oxygen, the action of ultraviolet light, or even the electrolytic action of an aqueous solution.

Conventionally, contaminated water has been purified using the oxidizing power of ozone. For example, in Europe, 190
Ozone treatment has been carried out for the purpose of sterilizing tap water since 2006, and it is also used throughout Japan for the purpose of decolorizing wastewater treatment at rice processing facilities. Furthermore, it is also used for the oxidation treatment of substances in industrial wastewater and special purpose water.

By the way, in this water treatment method using ozone, an aeration pipe or an injector is attached to the bottom of an ozone reaction tank filled with crushed stone or the like, and fine ozone-containing gas is diffused from the aeration pipe or injector. As a result, the ozone-containing gas in the bubbles rising from the bottom of the ozone reactive species dissolves in the water to be treated and comes into contact with a continuous layer of the water to be treated, thereby removing the 19 dye substances contained in the water to be treated. This is a method of purification by oxidation. This water treatment with ozone is used to oxidize dissolved organic matter in the water to be treated, and in particular, the reaction of unsaturated bonds such as coloring components is fast, and the decolorizing effect is extremely high.

(The section that the invention seeks to solve) However, in the water treatment method described above, the COD (chemical oxygen consumption) caused by ozone is reduced, and the amount of oxygen caused by the oxidation of various substances dissolved in the treated water is reduced. It was not very effective against dissolved molecules that depended only on Shigeko's melon and had no unsaturated bonds.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a water treatment method that reliably performs ozone oxidation even with dissolved organic matter having no unsaturated bonds and improves treatment efficiency with ozone. do.

[Purchase of the invention] (Means and effects for solving the problems) In order to solve the above problems, the present invention mixes a catalyst, which is an ozone reaction promoting medium, with treated water, and subjects this mixed water to an ozone reaction. The catalyst is sprayed on the gas-liquid contact filler inside the furnace, and the catalyst that is added to the treated water is adsorbed onto the surface of the gas-liquid contact filler. At this time, ozonized gas rises from the bottom of the ozone reaction tank through the gas-liquid contact filler, and this ozonized gas makes gas-liquid contact with the catalyst on the surface of the gas-liquid contact filler. , the ozone oxidation reaction can be promoted, and ozone oxidation can be reliably carried out even with dissolved organic substances having no unsaturated bonds.

(Example) Before describing the example of the method of the present invention, the most effective experimental example conducted by the present inventors in the process of solving the above problems will be described below.

In the process of conducting various experiments, the present inventors discovered that ozone oxidation treatment was effectively carried out when a suspended catalyst that promoted ozone oxidation reaction was dispersed in water. Therefore, we investigated various suspension catalysts and found that iron oxide, one of them, promotes the ozone oxidation reaction. Below, an example of the experiment will be described.

Experimental Example First, in the first experimental example, only the malonic acid solution was ozone treated, and specifically, malonic acid 100
After putting 250ml of ppm melt into an air washing bottle, it was treated with ozonized air at 0.5ρ/win (ozone concentration 15B/47), and over time COD, TOC (aircraft carbon), and PH (hydrogen ion concentration) The results shown in Table 1 were seen.

Table 1 Next, in the second experimental example, iron oxide was suspended in a malonic acid solution and ozone treatment was performed. Specifically, 250 ml of a solution containing 100 ppl of malonic acid and iron oxide
After putting 2.0g of c2o into the air washing bottle, 1ii
When ozone treatment was carried out using ozonized air at 0.5 D/win (ozone concentration 15 n+g/ρ), the results shown in Table 2 were obtained.

44 Table Therefore, as is clear from these two experimental examples, the second experimental example in which iron oxide was suspended and ozone treated had a higher CO
The amount of decrease in DSTOC is increasing. This means that
Normally, ozone oxidation is difficult to occur in acidic liquids, but it can be seen that the addition of iron oxide promotes the reaction even at pH 3 or lower. By suspending iron oxide in this way, the ozone treatment effect is improved, but this is because the iron oxide surface becomes a layer of h°organisms, making it more susceptible to ozone oxidation, and furthermore, the ozone and the It is thought that several substances promote decomposition through intermediate products such as peroxide and hydrogen peroxide produced by the reaction.

Therefore, in the method of the present invention, water treatment is performed using a catalyst that increases the ozone reaction efficiency.More specifically, bricks, crushed stones, etc. After adding the filler, a suspension in which the catalyst is uniformly mixed into the water to be treated is sprayed onto the filler in a thriller manner, thereby making it contact with the ozonized gas supplied from the bottom of the ozone reaction tank. I'm taking it.

Hereinafter, an embodiment of a water treatment apparatus to which the method of the present invention is applied will be described with reference to FIG. In the same figure, 11
This is an ozone reaction tank in which dissolved substances such as organic matter dissolved in the treated water are treated in airtight contact with ozone.This is formed into a vertical cylinder shape, and the middle part of the inside of the reaction tank is equipped with bricks, crushed stones, etc. The filler 12 is filled to form a layer with a predetermined thickness.

An ozone generator (
An ozone-containing gas introduction pipe 13 for introducing ozone (not shown) into the ozone reaction tank 11 is attached.

Further, in the ozone reaction tank 11, located on the lower side of the filler 12, there is a diffuser pipe 14 for diffusing the ozone-containing gas introduced from the ozone-containing gas introduction pipe 13 into the ozone reaction 'fJ11. It is located.

Reference numeral 15 denotes a dish-shaped separator serving as the bottom of the ozone reaction tank 11. Iron oxide 16, which serves as a suspended catalyst for promoting the ozone reaction, is deposited on the inner bottom of the separator tank 15, and ozone It has a function of separating and precipitating the suspended catalyst from the treated water treated in the reaction tank 11 to obtain treated water which is supernatant water. Reference numeral 17 denotes a treated water outflow pipe that drains the treated water to the outside.

Reference numeral 18 denotes a catalyst withdrawal valve for withdrawing the suspended catalyst settled in the separation tank 15 , and the suspended catalyst withdrawn by the catalyst withdrawal valve 18 is supplied to the mixing tank 19 . In this mixing tank 19, the treated water introduced from the treated water conduit pipe 20 and the catalyst extracted in the form of slurry by the catalyst extraction valve 18 are mixed.

Reference numeral 21 denotes a slurry pump, which takes in mixed water from the mixing tank 19 and sends it to a water spray pipe 22 provided above the filler 12 above the ozone reaction tank 11. 23 is an ozone decomposition device for treating unreacted ozone-containing gas in the ozone reaction tank 11.

Therefore, according to the ozone treatment apparatus as described above, when the treated water of the sewage τ is introduced into the 7, 7 joint 19 through the treated water conduit pipe 20, in this mixing tank 19, the treated water and the catalyst are removed. After being mixed with iron oxide 16, which is a catalyst for promoting the ozone reaction efficiency, which is pulled out from the valve 18, it is gradually sprinkled onto the filling material 12 for the ozone reaction Vj11 using the slurry pump 21.

At this time, ozone-containing gas introduction pipe 1 from the ozone generator
3, the ozone-containing gas is supplied to the aeration pipe 14 at the bottom of the ozone reaction tank 11, so that the ozone-containing gas is diffused to the western part of the ozone reaction tank 11 from the aeration pipe 14. The ozone-containing gas diffused by the aeration pipe 14 rises to the upper part of the ozone reaction tank 11 while making airtight contact with the slurry-like water to be treated flowing down inside the filler 12 .

Here, the iron oxide 16 contained in the water to be treated has a function of increasing reaction efficiency with ozone, and the filler 12 has a function of increasing gas-liquid contact with the water to be treated.

The water treated in the ozone reaction tank 11 as described above flows down the filler 12 and is stored in the tank #1ta 15. Therefore, in this separation tank 15, iron oxide 16, which is a suspended catalyst, is allowed to settle naturally in a tapered portion of the bottom, and treated water, which is supernatant water, is taken out to the outside through a treated water outflow pipe 17.

On the other hand, the iron oxide 16, which is a suspended catalyst settled at the bottom of the separation tank 15, passes through the opened catalyst withdrawal valve 18 in the form of a slurry and is led to the mixing tank 19. Therefore, iron oxide 1
6 can be used repeatedly in the ozone reaction tank 11.

In addition, in this treatment process, the ozone-containing gas that was not used for the ozone reaction in the ozone reaction Ie11 is led from the upper part of the ozone reaction tank 11 to the ozone decomposition device 23 for ozone decomposition, and after being rendered harmless here, it is released into the atmosphere. be discharged.

In the above example, a continuous flowing water treatment method is considered. By temporarily stopping the inflow of water, a certain amount of treated water stored in the separation tank 15 and the mixing tank 19 is circulated for a certain period of time, and then the process of flowing the treated water into the mixing tank 19 is repeated. A batch method may be adopted, and in this case, special wastewater and wastewater with high COD and TOC values can be treated with high efficiency. Moreover, it goes without saying that ozone reaction promoting catalysts other than iron oxide can be similarly applied as catalysts. Further, since the ozone oxidation reaction is promoted by the catalyst, it goes without saying that ozone in the ozonized gas with a high ozone concentration is effective. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Effects of the Invention] As explained above, according to the present invention, by passing the water to be treated in which the ozone reaction promoting medium (catalyst) is suspended through the filler of the ozone reaction tank, the treated water on the surface of the filler is Since the ozonated gas directly contacts the wet catalyst, it is possible to treat dissolved organic substances without unsaturated bonds by ozone oxidation, and water treatment using ozone can be carried out efficiently. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of a water treatment apparatus to which the method of the present invention is applied. 11... Ozone reaction tank, 12... Filler, 13...
・Ozone a gas introduction pipe, 14... Diffuser pipe, 15・
... Separation cypress, 16... Iron oxide (catalyst), 17... Treated water outflow pipe, 18... Catalyst withdrawal valve, 19... Mixing tank, 20... Treated water conduit pipe, 21 ...Slurry pump, 22...Water pipe, 23...Ozone decomposition device. Outsourcer agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] Mixing the catalyst, which is an ozone reaction promoting medium, and the water to be treated,
This mixed water is sprinkled on the gas-liquid contact filler inside the ozone reaction tank, and the ozonized gas rising from the bottom of the ozone reaction tank through the gas-liquid contact filler and the surface of the gas-liquid contact filler. 1. A water treatment method characterized by performing ozone oxidation treatment by bringing a catalyst mixed into treated water adsorbed into the water into gas-liquid contact with the catalyst.