JPS63221890A - Treatment method and equipment for organic matter-containing water - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the treatment of organic matter-containing wastewater discharged from semiconductor factories, etc., or the treatment of organic matter-containing wastewater used for the production of industrial pure water or the regeneration of used pure water. This article relates to a processing method and apparatus.

[Conventional technology]

When reusing purified water wastewater used in semiconductor manufacturing processes as industrial pure water, it is necessary to remove organic substances contained in the wastewater, such as low molecular weight alcohols such as methanol, ethanol, and isopropanol, and ketones. There must be. A known method for effectively removing these organic substances is to irradiate the water to be treated with ultraviolet rays to oxidize and decompose the organic substances.

When manufacturing and regenerating industrial pure water using such methods, conventionally only high-pressure mercury lamps or only low-pressure mercury lamps have been selectively used as ultraviolet light sources, and the water to be treated has been exposed to oxidizing agents such as hydrogen peroxide. The water to be treated was mixed with a chemical agent and the ultraviolet rays emitted from the lamp were applied to the water.

[Problem that the invention seeks to solve]

By the way, the relationship between the amount of UV irradiation and organic matter i (TOC) in water, which is a general characteristic of decomposing organic matter during UV oxidation treatment of organic matter contained in water, is as shown in Figure 5. The space between is T.

C decreases almost linearly, but the degree of decrease tends to slow down thereafter.

Therefore, in order to obtain treated water with a low TOC value, a large amount of ultraviolet irradiation is required. For this reason, large-capacity high-pressure mercury lamps are often used, but in practice they have the disadvantage that the light emitted from the lamps is inefficiently utilized and that power consumption increases due to continuous lighting.

On the other hand, using a low-pressure mercury lamp is superior to a high-pressure mercury lamp in terms of decomposition efficiency of organic matter, but it is difficult to increase the capacity and requires a long time, or the use of a high-pressure mercury lamp In order to obtain the same level of ultraviolet output, multiple lamps must be lit at the same time.

An object of the present invention is to provide a method and apparatus for efficiently treating organic matter-containing water by using a low-pressure mercury lamp and a high-pressure mercury lamp in combination.

[Means for solving problems]

The present invention is a method for treating organic matter-containing water in which an oxidizing agent is added to organic matter-containing water under ultraviolet irradiation to oxidize and decompose the organic matter contained in the water to be treated. Irradiate the water to be treated with lamp light,
A method for treating water containing organic matter, characterized in that the irradiation is then switched to irradiation with high-pressure mercury lamp light, and at least two or more cylindrical reaction tanks are connected in series, and an oxidizing agent is added to the inflow side of the water to be treated in each reaction tank. This is an apparatus for treating organic matter-containing water, characterized by having a low-pressure mercury lamp built into the first-stage reaction tank, and a high-pressure mercury lamp built into the second-stage reaction tank.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the apparatus of the present invention. In the figure, 1
, 2 is a cylindrical reaction tank made of stainless steel or the like. The water supply pipes 1a and 2a of each of the reaction vessels 1 and 2 have an oxidizing agent addition and supply port 3, respectively. In addition, each reaction tank 1
, 2 have a mirror finish on their inner surfaces to increase the reflection efficiency of ultraviolet light.

Reaction tank 1 is used in the first stage, reaction tank 2 is used in the second stage, and its water supply pipe 2a is communicated with the water supply pipe 1b of the reaction tank 1 in the previous stage, and both reaction tanks 1 and 2 are connected in series.

In addition, a cylindrical jacket 4 made of high-purity quartz glass or the like with excellent ultraviolet transmittance is installed in the longitudinal direction inside both the reaction tanks 1 and 2, and inside the jacket 4, the reaction tank 1 in the previous stage is On the other hand, a low-pressure mercury lamp 5 is installed inside the reaction tank 2, and a high-pressure mercury lamp 6 is installed inside the reaction tank 2 at the rear stage.

In the embodiment, water to be treated containing organic substances, especially alcohols such as methanol, ethanol, and isopropanol, and ketones is first introduced into the reaction tank 1 at the front stage through its water supply pipe 1a.
The oxidizing agent is added to the reactor, which is then oxidized with light from a low-pressure mercury lamp.Then, the oxidizing agent is added to the reactor, which is then oxidized with light from a high-pressure mercury lamp. Organic matter contained in the treated water is decomposed and removed, and treated water is obtained from the water pipe 2b.

FIGS. 2 and 3 show processing characteristics using low-pressure mercury lamp light and high-pressure mercury lamp light.

Figure 2 shows the TO results when water to be treated containing methanol is treated separately using a 0.5KW low-pressure mercury lamp in the first reaction tank and an IKν high-pressure mercury lamp in the second reaction tank.
As is clear from Figure 0, which shows the relationship between C and lamp light irradiation time, the processing efficiency of high-pressure mercury lamps is more than twice as low as that of low-pressure mercury lamps. However, while the capacity of a low-pressure mercury lamp is limited to 0.5 KW at most, a high-pressure mercury lamp can have a capacity of 10 KV, 20 KW, or more. For example, when a high-pressure mercury lamp with a capacity of 6 KV is used and the throughput of a low-pressure mercury lamp with a capacity of 0.5 KW is set to 1, the throughput is four times as high.

However, this treatment using only light from a high-pressure mercury lamp requires 12 times the capacity compared to treatment using only light from a low-pressure mercury lamp, and is not necessarily effective. By the way, when organic matter-containing water is industrially treated, it is carried out by continuous treatment, but in this case, the amount of ultraviolet energy that the water to be treated receives becomes a problem.

FIG. 3 shows the relationship between TOC and ultraviolet irradiation amount when treated water containing methanol was treated at a rate of 5 t/h. In Figure 3, according to the treatment with low-pressure mercury lamp light, TO
It is possible to process 27.5 ppm down to 4 ppm with the C value decreasing linearly. A total of 20 low-pressure mercury lamps with a capacity of 0.5 KV can be installed to obtain an ultraviolet irradiation amount of 2 υ·hr/rd.

However, in order to further reduce the TOC value from 4 ppm+ to 0.1 ppm using only low-pressure mercury lamp light, an ultraviolet irradiation amount of 3 KIi-hr/7'n' is required.

To obtain this dose, 30 low-pressure mercury lamps are required, and a total of 50 lamps must be used in the case of a two-stage process. Even if this were divided into a front stage and a rear stage and incorporated into the reaction tank, it would be too large-scale and impractical in terms of maintenance and initial costs. However, as shown in Figure 3.

According to the use of high-pressure mercury lamps, in order to reduce the TOC value from 4 ppm to 0.1 ppm,
It is enough to use this book.

Therefore, when treating organic matter-containing water containing methanol at a TOC value of 27.5 ppm at a rate of 50 t/h, 20 low-pressure mercury lamps with a capacity of 0.5 V are installed in the reaction tank 1 in the first stage. , l0KI is in the reaction tank 2 at the rear stage.
If four high-pressure mercury lamps with a capacity of I are installed and oxidation treatment is performed while supplying the necessary amount of oxidizing agent into the reaction tank 1.2 of each stage, the TOC of methanol in the water to be treated can be reduced to 0. lpp
It can be easily disassembled up to m.

FIG. 4 shows the effect characteristics of the present invention. As is clear from the figure, low-pressure mercury lamp light, which has a low ultraviolet capacity but has excellent treatment efficiency, is used for processing within the range where oxidative decomposition proceeds smoothly, and high-pressure mercury lamp light with a large capacity is used for subsequent processing. By the way.

It can be seen that it is possible to efficiently treat a low concentration of organic matter with less power consumption than when using only a high-pressure mercury lamp, and that the treatment time can be shortened compared to when using only a low-pressure mercury lamp.

In the above embodiments, an example was shown in which the reaction tank was arranged in two stages, but depending on the throughput, it may be divided into three or more stages, and a batch system can also be applied.

[Effects of the Invention] As described above, according to the present invention, a low-pressure mercury lamp and a high-pressure mercury lamp are used together, and by irradiating low-pressure mercury lamp light in the first stage of the treatment process of organic matter-containing water and high-pressure mercury lamp light in the latter stage, , it becomes possible to continuously and efficiently decompose organic matter contained in the water to be treated to a low concentration,
We aim to shorten processing time and reduce power consumption, and reduce C in wastewater such as the production and recycling of pure water used in various fields and domestic wastewater.
Excellent effects can be obtained in reducing OD and n-hexa concentration.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing one embodiment of the device of the present invention, and FIG.
The figure shows the relationship between ultraviolet irradiation time and TOC change for methanol decomposition using high-pressure mercury lamps and low-pressure mercury lamps. FIG. 4 is a diagram showing the relationship with changes in TOC, FIG. 4 is a diagram showing processing characteristics according to the present invention, and FIG. 5 is a diagram showing a general decomposition characteristic curve for organic matter.

Claims (2)

[Claims] (1) In a method for treating organic matter-containing water in which an oxidizing agent is added to organic matter-containing water under ultraviolet irradiation to oxidize and decompose the organic matter contained in the water to be treated, low-pressure mercury is A method for treating water containing organic matter, which comprises irradiating the water to be treated with lamp light and then switching to irradiation with high-pressure mercury lamp light. (2) At least two or more cylindrical reaction tanks are connected in series, each reaction tank is equipped with an oxidizing agent addition port on the inflow side of the water to be treated, a low-pressure mercury lamp is built in the first stage reaction tank, and the second stage An organic matter-containing water treatment device characterized by a high-pressure mercury lamp built into the reaction tank.