JPH07102357B2 - Apparatus and method for treating water containing organochlorine compound - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an apparatus and method for treating water containing an organic chlorine compound suitable for removing organic chlorine compounds contained in groundwater or the like, particularly trichloroethylene / 1-1-1 trichloroethane / tetrachloroethylene. Regarding

[0002]

2. Description of the Related Art In recent years, there has been a problem that a degreasing agent for dry cleaning and an organic chlorine compound used in a cleaning solution for the metal industry and the electronics industry adversely affect the human body.
As the organic chlorine compound, trichlorethylene / 1
-1-1 There are trichloroethane, tetrachloroethylene, etc., which are heavier than water and difficult to spontaneously decompose,
There is a problem of environmental pollution such as pollution of groundwater. Methods for removing organic chlorine compounds in groundwater include activated carbon adsorption method, air aeration method, microbial decomposition method, and light irradiation method using a catalyst.

In the activated carbon adsorption method, for example, granular, fibrous,
Using a bead-shaped activated carbon, an organic chlorine compound can be adsorbed on and removed from the activated carbon. However, there is a problem that it takes time and labor for granulating and refining, reprocessing, or replacement, resulting in high running cost.

As an air aeration method, for example, 1984, 2
Monthly issue of Japan Water Works Association Vol. 53, No. 2 (No. 593)
Pp. 105-117 or pp. 61-171
As disclosed in Japanese Patent No. 594, a diffusion layer composed of a gas-liquid contact filler for stripping volatile organic chlorine compounds in raw water is provided in the tower, and raw water is flowed down from the upper part of the diffusion layer. There is a method in which an organic chlorine compound in water is removed by introducing a stripping gas from the lower part of the diffusion layer and contacting with gas and liquid. In this air aeration method, when the organic chlorine compound that has been volatilized in the air in the tower is released into the atmosphere,
Once again, there is a problem of being included in raindrops and returning to the soil.
Therefore, for the treatment of the exhaust gas, adsorption by activated carbon or activated carbon fibers may be considered, but there is a problem that it takes time for regeneration treatment / replacement and the running cost is high.

Further, in the microbial decomposition method, for example, Japanese Patent Laid-Open No.
As disclosed in JP-A-92274, by contacting a specific microorganism with an aliphatic chlorine compound, the volatile aliphatic chlorine compound can be decomposed and removed. However, this microbial decomposition method is under study, and there is a problem that it takes a considerable time before it is put into practical use.

In the light irradiation method using a catalyst, for example, as disclosed in JP-A-2-107314, exhaust gas containing a volatile organochlorine compound is contacted with titanium dioxide for light irradiation to volatilize. Most of the organic chlorine compounds can be removed. However, since hydrogen chloride, chlorine, etc. generated after decomposition are removed by alkali cleaning, there is a problem that the processing becomes complicated, such as requiring separate equipment.

[0007]

SUMMARY OF THE INVENTION In view of the above problems of the prior art, the main object of the present invention is a treatment apparatus and method for removing organic chlorine compounds contained in water, which is an industrial method. An object of the present invention is to provide an apparatus and method for treating water containing an organic chlorine compound, which has been improved to be economical.

[0008]

According to the present invention, the object is to vaporize the organic chlorine compound contained in the water by bringing the water containing the organic chlorine compound to be treated into contact with a gas. A means for liquid contact treatment, a means for absorbing the vaporized organochlorine compound in the oil by contacting a gas containing an organochlorine compound vaporized by the gas-liquid contact treatment with an oil, and Means for separating an organic chlorine compound by distilling oil having absorbed the organic chlorine compound, or a water treatment apparatus containing the organic chlorine compound, or containing an organic chlorine compound to be treated A step of subjecting water to a gas-liquid contact treatment, a step of absorbing an organic chlorine compound vaporized by the gas-liquid contact treatment into oil, and a distillation of the oil absorbing the organic chlorine compound. Is achieved by providing a method of treating water containing organic chlorine compounds, characterized by having the steps.

[0009]

By doing so, the organic chlorine compound can be vaporized and taken out by subjecting the water containing the organic chlorine compound to gas-liquid contact treatment, and at this time, when the organic chlorine compound is condensed in oil distillation. The temperature inside the aeration tower can be increased by using the heat source absorbed in the gas, and the removal rate of the organochlorine compound can be improved, and the vaporized organochlorine compound is absorbed by the oil to remove the organochlorine compound from the gas. The exhaust can be purified. Further, by distilling the oil that has absorbed the organochlorine compound and vaporizing and removing the organochlorine compound, the oil can be reused and the vaporized organochlorine compound can be liquefied and recovered. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing an entire water treatment apparatus to which the present invention is applied. As shown in FIG. 1, for example, a tower 1 as a container formed in a cylindrical shape is
Each of the upper and lower rooms 1a.1 by the shelves 2 provided in the middle part
It is divided into b. The shelf 2 has an opening 2a at the center thereof and is formed in a trumpet shape so as to push the radially inner side upward than the outer side.

A gas-liquid contact filler 3, which may be, for example, a Raschig ring, is provided in the middle of the lower chamber 1a with a predetermined thickness in the height direction, and the tray 2 and the filler 3 are provided. A watering head 4 is provided between and. A submersible pump 5 is installed in a well outside the tower 1, for example,
Water to be treated is pumped from the submersible pump 5 to the sprinkling head 4. Then, the water discharged from the sprinkling head 4 flows down through the filling material 3 and is stored in the water storage section 1c defined by the bottom of the tower 1.

A blower port 6 is provided between the filling material 3 and the water storage section 1c. The blower port 6 is connected to a blower port of a blower 7 arranged outside the tower 1,
Air is blown from below toward the filler 3. Further, this blower may be provided on the outlet side of the tower to suck air. As a result, the water flowing down through the filler 3 can be subjected to aeration treatment to volatilize the organochlorine compound dissolved in the water so that the concentration difference between the two becomes equilibrium. it can. The organic chlorine compound contained in the well water is, for example, trichloroethylene / 1-1-1 trichloroethane / tetrachloroethylene.

In the middle of the upper chamber 1b, a filler 8 which may be Raschig rings, for example, is provided with a predetermined thickness in the height direction in the same manner as above, and above the filler 8 is provided. Is provided with an oil sprinkling head 9 composed of, for example, a distributor. By the way, by the upper surface of the tray 2 and the inner wall surface of the tower 1 formed as described above,
An oil storage portion 11 is formed so as to be recessed upward,
An oil pump 13 connected via a circulation pipe 12 is arranged outside the tower 1 in order to circulate oil between the oil reservoir 11 and the oil spraying head 9. The oil is pumped by the oil pump 13 and the oil sprinkling head 9
The oil is discharged from the container and drops through the filling material 8 and falls into the oil storage section 1
1, but when passing through the filler 8, the lower chamber 1
Gas-liquid contact is made with the organic chlorine compound in the gas rising from a, and the organic chlorine compound is absorbed by the oil. Therefore, the oil may be any one that can suitably absorb an organic chlorine compound, and may be, for example, a lubricating oil that is a mechanical oil or a mineral oil, and an oil having a higher boiling point and a stabler than the organic chlorine compound to be removed. If it is good.

Above the opening 2a of the shelf 2, a filler 8 is provided.
A cap 14 is provided so that the oil falling inside does not drop into the lower chamber 1a through the opening 2a. Further, a mist eliminator 15 is provided above the oil sprinkling head 9 in the upper chamber 1b, and the oil mist discharged from the oil sprinkling head 9 is captured by the mist eliminator 15 and is sent to the outside of the tower 1. The mist is not discharged. An exhaust port 16 is provided at the top of the tower 1, and the air blown from below to above in the tower 1 is exhausted from the exhaust port 16. In addition, inside the tower 1 of the exhaust port 16, the auxiliary adsorbent 1 which may be, for example, activated carbon
7 is provided, and purified air is exhausted from the exhaust port 16.

One end of a branch pipe 18 is connected to an intermediate portion of the circulation pipe 12 on the discharge side of the oil pump 13, and the other end thereof is connected to an evaporator 19. In addition, the circulation pipe 12 and the branch pipe 18 are provided with electromagnetic valves 21a and 21b, respectively, on the respective downstream sides of their respective branch points. Normally, the solenoid valve 21a on the circulation pipe 12 side is opened to open the branch pipe 1
By closing the solenoid valve 21b on the 8th side,
It is possible to circulate oil between 1 and the oil spraying head 9. Then, by closing the solenoid valve 21a on the side of the circulation pipe 12 and opening the solenoid valve 21b on the side of the branch pipe 18, when the oil is reduced in its ability to dissolve the organic chlorine compound, the oil is appropriately vaporized 19 Can be sent to.

The evaporator 19 comprises a closed container,
A partition wall 19 that rises from the vicinity of the bottom surface of the peripheral wall toward the ceiling wall and leaves a gap between itself and the ceiling wall.
a is provided and is formed in a double wall structure. The oil sent from the above branch pipe 18 is the partition wall 1
It is stored in the inner bottom surrounded by 9a, and the heater 22 is provided in the bottom. In the evaporator 19, the oil stored at the bottom of the evaporator 19 is heated by the heater 22 to evaporate the organic chlorine compound and the like dissolved in the oil due to the difference in boiling point. A cooling pipe 23 is provided so that the steam is cooled and liquefied to be accumulated between the partition wall 19a and the peripheral wall.

In order to reuse the oil from which the organic chlorine compounds have been removed and which has been stored at the bottom of the evaporator 19, as the oil for gas-liquid contact in the tower 1, the bottom of the evaporator 19 and
A pipe is connected to the oil storage portion 11 in the tower 1, and an oil pump 24 is provided in the middle of the pipe. Further, the liquid stored in the storage portion by the partition wall 19a of the evaporator 19 contains oil and a small amount of water in addition to the organic chlorine compound, but these are collected for separation by the difference in specific gravity. A recovery tank 25 is provided so as to communicate with the evaporator 19 via a recovery pipe.

In the recovery tank 25, the organic chlorine compound C, water W, and oil O are separated in this order from the bottom. The recovery tank 25 is arranged so that the oil separated into the upper layer in the recovery tank 25 is appropriately returned to the oil storage section 11 in the tower 1 for reuse.
The tower 1 and the tower 1 communicate with each other via an oil pump 24. In addition, in order to selectively return the oil in the evaporator 19 and the oil in the recovery tank 25 into the tower 1 by the oil pump 24, the evaporator 19 and the recovery tank 25 are separated from the oil pump 24 by the oil pump 24. Electromagnetic valves 21c and 21d and a liquid level detector are provided respectively, and an electromagnetic valve 21e is also provided downstream of the oil pump 24. In addition, the collection tank 25
The organic chlorine compound in the lower layer of the inside is supplied to the user and is reused.

The cooling pipe 23 in the evaporator 19 is pipe-connected to the lower packing material 3 in the tower 1 or, for example, a heat transfer plate 26 piped in the lower part 1C of the tower. In order to circulate the cooling water, a water storage tank 27 and a pump 28 are arranged in an intermediate portion of the pipe where the cooling water flows from the heat transfer plate 26 toward the cooling pipe 23.
Therefore, the organic chlorine compound can be condensed (cooled) in the cooling pipe 23 without a new medium such as steam or equipment, and conversely, the cooling water warmed by the heat transfer passes through the heat transfer plate 26. As a result, the ambient temperature of the lower filler 3 and the temperature of the treated water increase, so that the gas-liquid contact treatment can be greatly promoted. The heat transfer plate 26 is cooled by the latent heat of vaporization of treated water and convective heat transfer, and the surplus heat increases the enthalpy of the air passing through the tower and moves to the upper part. Further, a pipe and a pump 29 for supplying the user with the purified treated water stored in the water storage unit 1c are connected to the water storage unit 1c of the tower 1.

The various pumps, solenoid valves, and the like in the processing apparatus thus configured are controlled by a control device (not shown) and appropriately driven. According to the present device, in the lower room 1a of the tower 1, air is sent from below to the water flowing down through the packing material 3 to achieve the same processing speed as that of the conventional air aeration method or the heat transfer plate. Two
Due to the accelerating effect of 6, water can be purified at a higher processing speed. And the opening 2a
In the upper chamber 1b, the organochlorine compound contained in the air sent into the upper chamber 1b via the solvent can be suitably dissolved in the oil flowing down in the filler 8 and removed from the air. it can. Therefore, the frequency of maintenance can be greatly reduced as compared with the conventional method in which exhaust gas after aeration is entirely treated with an adsorbent.

In the upper room 1b of the above embodiment,
The gas-liquid contact treatment was performed using the filling material 8. However, without being limited to this, for example, a plurality of shelves provided with bubble caps are provided, and oil is transferred to the lower shelves through a downcomer for each shelf. The gas-liquid contact treatment may be performed with the bubble caps on the respective shelves so that they fall.

[0023]

As described above, according to the present invention, the treatment of water containing an organic chlorine compound can be favorably carried out, and an adsorbent such as activated carbon can be treated against various methods for conventional organic chlorine compounds. The frequency of reproduction and replacement can be greatly reduced,
The organic chlorine compound can be recovered and reused, the running cost can be reduced, and the water can be efficiently treated.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an entire groundwater treatment apparatus to which the present invention is applied.

[Explanation of symbols]

 1 Tower 1a Lower Room 1b Upper Room 1c Water Reservoir 2 Shelf 2a Opening 3 Filler 4 Sprinkler Head 5 Submersible Pump 6 Blower 7 Blower 8 Filler 9 Sprinkler Head 11 Oil Storage 12 Circulation Piping 13 Oil Pump 14 Cap 15 Mist eliminator 16 Exhaust port 17 Auxiliary adsorbent 18 Branch pipe 19 Evaporator 21a-21e Solenoid valve 22 Heater 23 Cooling pipe 24 Oil pump 25 Recovery tank 26 Heat transfer plate 27 Water storage tank 28 Pump 29 Pump

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C02F 1/20 A 1/58 ZAB A

Claims (2)

[Claims] 1. Means for subjecting an organic chlorine compound contained in water to gas-liquid contact treatment by bringing water containing an organic chlorine compound to be treated into contact with a gas, and vaporizing by the gas-liquid contact treatment. By contacting a gas containing an organic chlorine compound with an oil, means for absorbing the vaporized organic chlorine compound into the oil, and distilling the oil absorbing the organic chlorine compound to obtain the organic chlorine compound An apparatus for treating water containing an organic chlorine compound, characterized in that it has a means for separating. 2. A step of subjecting water containing an organic chlorine compound to be treated to a gas-liquid contact treatment, a step of absorbing an organic chlorine compound vaporized by the gas-liquid contact treatment into oil, and a step of absorbing the organic chlorine compound. And a step of distilling oil, the method for treating water containing an organic chlorine compound.