JPH0523681A - Treatment and device for photooxidation - Google Patents

Abstract

PURPOSE:To efficiently separate and recover a particulate such as titanium dioxide by passing a water to be treated, in which the particulate such as titanium dioxide is suspended, around an ultraviolet lamp to ultraviolet irradiation treat and feeding to a sedimentation vessel to sedimentate the catalyst particulate in the water to be treated. CONSTITUTION:The water to be treated is fed from the water feed opening 2 into the reactor vessel 1, in which the catalyst particulate such as titanium dioxide is added and is suspended by the stirring apparatus M, to keep a specific water level. And the water to be treated flows down along the ultraviolet lamp 6 and is irradiated with ultraviolet rays to decompose an organic material in the water to be treated and to sterilizing treat or the like by catalytic action of the titanium dioxide particulate. The treated water is fed to the inner cylinder 9 of the 1st sedimentation vessel and the catalyst particulate, a part of which is catched by the filter membrane 10, is sedimentated. The other hand, the supernatant treated water is fed into the inner cylinder 13 of the 2nd sedimentation vessel and the residual catalyst particulate 7 is sedimentated and is catched by the filter membrane 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photooxidation treatment method and apparatus using semiconductor fine particles such as titanium dioxide as a catalyst.

[0002]

2. Description of the Related Art Waste water containing halogen, organic substances, etc., pool water, drinking water, etc. have been decomposed by activated sludge, oxidative decomposition, etc., but these existing treatment methods require a long time and a vast space. Therefore, it is not a rational method. Further, although sterilization of pool water or the like has conventionally been performed with chemicals such as chlorine, sterilization with chemicals tends to be refrained from the influence on the human body.

On the other hand, the sterilization of water to be treated using ultraviolet rays, unlike the chemical sterilization method, has almost no effect on the human body and can effectively decompose and sterilize hardly-decomposable halogen wastewater at the same time. It has the characteristics of being applied to various production fields, and the demand is increasing.

The most efficient sterilization method using ultraviolet rays is that an ultraviolet lamp whose outer periphery is covered with a protective tube is inserted into a processing tank whose both ends are open, and both ends of the processing tank are covered. This is a method in which a photocatalytic reaction tank connected to a water supply pipe or a drainage pipe of treated water is used to simultaneously perform the hardly decomposable halogen decomposition treatment and the sterilization while the treated water passes around the ultraviolet lamp.

On the other hand, it is known that when fine particles of titanium dioxide or the like are suspended in the water to be treated which is irradiated with ultraviolet rays, the catalytic action of these fine particles enables more effective decomposition treatment and simultaneous sterilization treatment. There is.

[0006]

However, when the two methods are combined as described above and fine particles such as titanium dioxide are suspended in the water to be treated and passed around the ultraviolet lamp to carry out the decomposition purification sterilization treatment. Is extremely difficult to separate and recover titanium dioxide fine particles from the treated water, and these titanium dioxide fine particles are completely separated,
There is a problem that a large-scale separation device is required for recovery.

When fine particles of titanium dioxide or the like are separated by various types of membranes and are recovered and reused at the same time as the concentrated liquid, it is necessary to regularly wash the membranes so that the membranes are not clogged.

In view of the above situation, the present invention suspends fine particles of titanium dioxide or the like in the water to be treated and passes them around the ultraviolet lamp to carry out the ultraviolet irradiation treatment, so that titanium dioxide or the like contained in the water after the treatment. The object of the present invention is to propose a method and an apparatus for separating and recovering the above fine particles.

[0009]

In order to solve the above problems, according to the present invention, a reaction tank having an ultraviolet irradiation lamp inserted therein is provided with one or two or more stages of precipitation tanks in parallel, and a catalyst is provided in the reaction tank. The water to be treated in which the fine particles are suspended is fed, and while the water level in the reaction tank is kept constant, ultraviolet rays are radiated from the lamp to purify and treat the water to be treated with the catalyst fine particles, and then in the reaction tank. The treated water of the above is sent to a settling tank by overflowing, the catalyst fine particles in the treated water are settled and separated in the settling tank, and all or part of the treated water containing the catalyst fine particles is treated from the bottom of the settling tank if necessary. The present invention proposes a photo-oxidation treatment method and apparatus for returning it to the bath.

In the present invention, as the ultraviolet irradiation lamp, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp or the like can be used depending on the type of water to be treated.

[0011]

That is, in the present invention, the treated water containing the catalyst fine particles is irradiated with ultraviolet rays in the reaction tank to purify and treat the treated water, and the treated water is allowed to overflow into the settling tank. Since the catalyst fine particles contained in (3) are precipitated and separated, the catalyst fine particles such as titanium dioxide used in the photooxidation treatment method can be effectively separated and recovered.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiments. FIG. 1 shows an embodiment of the present invention.
Reference numeral 1 is a reaction tank having a water supply port 2 in the upper part and a drain port 3 in the lower part, and a heater 4 is provided on the outer periphery of the reaction tank 1.
An ultraviolet lamp 6 having a quartz protective tube 5 provided on the outer periphery thereof is inserted into the inside of the container. A stirrer M is provided on the bottom or side of the reaction tank 1.

The water to be treated is supplied from the water supply port 2 into the reaction tank 1 so as to keep a constant water level a in the reaction tank 1 and to add catalyst fine particles 7 such as titanium dioxide.
In the reaction tank 1, the catalyst fine particles 7, ... Are suspended in water by the stirrer M. In addition, the heater 4 heats it, and in such a state, it flows down along the ultraviolet lamp 6. During this period, while being irradiated with ultraviolet rays, the organic substances in the water to be treated are decomposed and sterilized by the catalytic action of fine particles of titanium dioxide.

Reference numeral 8 is a first settling tank having a diameter-reduced bottom. An inner cylinder 9 is inserted into the first settling tank 8 in the vertical direction, and a filtration membrane 10 is provided at the bottom of the inner cylinder 9. Further, a drainage port 11 is provided above the first settling tank 8. Similarly, 12 is a second settling tank having a diameter-reduced bottom. An inner cylinder 13 is inserted into the second settling tank 12 in the vertical direction, and a filtration membrane 14 is provided at the bottom of the inner cylinder 13. A drain port 15 is provided above the second settling tank 11.

On the other hand, a drainage port 3 provided at the bottom of the reaction tank 1 is provided with a first drainage channel 16, and the top of the first drainage channel 16 is lower than the water level a of the water to be treated in the reaction vessel 1. The drainage port is located at the center on the first settling tank 8 as described in 1.

Similarly, the drainage port 11 provided in the upper part of the first settling tank 8 is provided with the second drainage channel 17, and the top of the second drainage channel 17 is the water level of the treated water in the reaction tank 1. The drainage port is located at the center on the second settling tank 12 so as to be lower than a.

Further, there is provided a connecting path 18 connecting the upper part of the reaction tank 1, the bottom of the first settling tank 8 and the bottom of the second settling tank 12,
A pressure pump is provided in the communication path 18 between the reaction tank 1 and the first settling tank 8.
19 is provided, and valves 20 and 2 are provided in the connecting passage 18 below the bottoms of the first settling tank 8 and the second settling tank 12, one of which is connected to the drain.
0 is provided.

In the photooxidation treatment apparatus as described above, the water treated in the reaction tank 1 as described above is stored in the first settling tank 8 by the water level difference of the water level a of the reaction tank 1 from the first drainage channel 16. It is supplied into the cylinder 9.

In the supplied treated water, the catalyst fine particles 7, ... Are sedimented and separated in the inner cylinder 9, and a part of the separated catalyst fine particles 7 ,.

On the other hand, the supernatant treated water obtained by settling and separating the catalyst fine particles 7, ... Is supplied from the second drainage channel 17 into the inner cylinder 13 of the second settling tank 12 due to the water level difference a of the reaction tank 1, and the same as above. In the inner cylinder 13, the catalyst fine particles 7, ... contained in the treated water are sedimented and separated, and a part of the separated catalyst fine particles 7 ,.
The treated water collected in 14 and the supernatant is drained from the drain port 15.

Further, the treated water containing the catalyst fine particles 7, ... Collected at the bottoms of the first settling tank 8 and the second settling tank 12 are valves 20, 20.
May be switched to the drain side to be discharged to the outside, or the pressure feed pump 19 may be operated to return all or part of it to the processing tank 1.

The ratio of treated water supplied to the first settling tank 8 and the second settling tank 12 is, for example, 3: 1.

[0023]

In summary, according to the present invention, fine particles such as titanium dioxide are suspended in the water to be treated and passed through the periphery of the infrared lamp to carry out the ultraviolet irradiation treatment, so that the titanium dioxide contained in the treated water is treated. It is possible to efficiently separate and collect fine particles such as.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

[Explanation of symbols]

1 reaction tank 6 UV lamp 7, ... Catalyst fine particles 8 First settling tank 12 Second settling tank

Claims (2)

[Claims] 1. A reaction tank in which an ultraviolet irradiation lamp is inserted,
One or two or more stages of settling tanks are installed side by side, and water to be treated in which catalyst fine particles are suspended is fed into the reaction tank, and ultraviolet rays are irradiated from the above lamp while keeping the water level in the reaction tank constant. Then, the water to be treated is purified and treated with the catalyst fine particles, and then the treated water in the reaction tank is overflowed and sent to the settling tank, where the catalyst fine particles in the treated water are separated by sedimentation from the bottom of the settling tank. Is a photooxidation treatment method, wherein all or part of the treated water containing catalyst fine particles is returned to the above reaction tank if necessary. 2. A reaction vessel having an ultraviolet irradiation lamp inserted therein,
A photo-oxidation treatment device, wherein one or two or more stages of precipitation tanks are arranged in parallel.