JP2001017995A - Treatment of volatile organochlorine compound and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and surely treat and detoxify dichloroethylene, trichloroethylene or tetrachloroethylene. SOLUTION: The air contg. the dichloroethylene, trichloroethylene or tetrachloroethylene extracted from sewage in an extractor 2 is irradiated 7 with UV to oxidize these chloroethylene compounds to a hydrophilic primary by-product. The air contg. the primary by-product is brought into contact with water to hydrate the primary by-product into an easily decomposable secondary by-product, and the pH of the water contg. secondary by-product is controlled from neutral to alkaline. A nitrogen compd. and a phosphorus compd. are added thereto, and these chloroethylene compounds are decomposed by the microorganism deposited on the activated carbon packed in a biological activated-carbon tank 25 by using the secondary by-product as a carbon source. An org. matter need not be separately added in this way, and sewage is efficiently treated, and the treating cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for treating volatile organic chlorine compounds which decompose volatile organic chlorine compounds such as dichloroethylene, trichloroethylene and tetrachloroethylene.

[0002]

2. Description of the Related Art Conventionally, trichloroethylene (CHCl =
CCl ₂ ) or tetrachloroethylene (CCl ₂ = CCl
_{As a} method for treating a volatile organic chlorine compound having a chlorine group such as ₂ ), for example, as described in JP-A-8-281066 and JP-A-9-122441, a volatile organic chlorine compound is decomposed. A configuration is known in which the organic chlorine compound hydrophilized is dissolved in water to perform biological treatment.

[0003] That is, the one described in Japanese Patent Application Laid-Open No. 8-281066 discloses a method in which a gas containing a volatile organic chlorine compound is irradiated with ultraviolet rays to convert the volatile organic chlorine compound into dichloroacetyl chloride, monochloroacetyl chloride, or the like. Decomposes into hydrochlorinated organochlorine compounds such as acetyl chloride, filled with a filler that supports microorganisms provided in the biological treatment tank, passed through a packed bed that has been sprinkled and moistened from above, and It is biologically treated and oxidatively decomposed to the final decomposition products, hydrogen chloride and carbon dioxide.

[0004] Further, in the method disclosed in Japanese Patent Application Laid-Open No. 9-122441, a gas containing a volatile organic chlorine compound is irradiated with ultraviolet rays to decompose the volatile organic chlorine compound into an organic chlorine compound such as acetyl chloride. Then, a gas containing an organic chlorine compound such as acetyl chloride is aerated and dissolved in water, and a reducing substance such as a chlorine compound that inhibits the growth of aerobic organisms is added, and the gas is contacted with activated carbon. The biological treatment is carried out.

[0005] Incidentally, tetrachloroethylene (CCl
₂ = CCl ₂ ) is aerobic microorganism having only one carbon source, trichloroacetic acid, which is a haloacetic acid produced by contacting trichloroacetyl chloride, which is a byproduct produced by hydrophilizing water, with water. It is known that the growth rate is very low. For this reason, Japanese Patent Application Laid-Open No.
As described in Japanese Patent No. 281066 and Japanese Patent Application Laid-Open No. 9-122441, in a configuration in which a volatile organic chlorine compound is decomposed and hydrophilized, and the hydrophilized organic chlorine compound is dissolved in water and subjected to biological treatment, Dichloroacetic acid, which is a haloacetic acid formed from trichloroethylene (CHCl = CCl ₂ ), can be treated, but tetrachloroethylene (C
When trichloroacetic acid (CCl ₃ COOH), which is a by-product produced by hydrophilizing Cl ₂ = CCl ₂ ), is treated with an aerobic microorganism, it can be treated by staying at a dilute concentration for a long time. At a certain concentration, almost no biological treatment is possible.

For this reason, trichloroacetic acid produced by the decomposition of tetrachloroethylene is further subjected to treatment such as further oxidative decomposition with ultraviolet rays or peroxide, or thermal decomposition with alkali or the like. In addition, a large amount of processing energy is required, and harmful by-products may be generated. In addition, the method of performing adsorption separation using activated carbon or the like requires frequent replacement of activated carbon, resulting in a problem that the processing becomes complicated and a large processing cost is required.

[0007]

As described above, as described above, Japanese Patent Application Laid-Open Nos. 8-281066 and 9-12 are disclosed.
In a configuration for biological treatment by dissolving a hydrophilized organic chlorine compound in water as described in Japanese Patent No. 2441, tetrachloroethylene (CCl ₂ = CCl ₂ ) and trichloroacetic acid generated by the hydrophilization treatment of tetrachloroethylene. There is a problem that it is difficult to efficiently detoxify the harmful substance by biological treatment. Further, methods such as oxidative decomposition and adsorption / separation have a problem that the treatment is complicated and time-consuming, and the treatment cost is increased.

The present invention has been made in view of the above problems, and a method and apparatus for treating a volatile organic chlorine compound that efficiently and reliably treats dichloroethylene, trichloroethylene, or tetrachloroethylene to make them harmless. The purpose is to provide.

[0009]

According to a first aspect of the present invention, there is provided a method for treating a volatile organic chlorine compound from wastewater containing at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene. Extracting the volatile organic chlorine compound, irradiating the extracted volatile organic chlorine compound with ultraviolet rays in the presence of oxygen to produce a hydrophilic primary by-product,
The secondary by-product is brought into contact with water whose pH has been adjusted to a range from alkaline to neutral to hydrate to form a readily decomposable secondary by-product. The second by-product is decomposed by a microorganism which is added to at least one of a compound and a nitrogen compound and supported on activated carbon.

[0010] Then, ultraviolet rays are irradiated to at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene extracted from the wastewater in the presence of oxygen to efficiently produce hydrophilic first by-products. The primary by-product is oxidized into water, and the easily decomposable secondary by-product produced by hydration by contacting the primary by-product with water whose pH has been adjusted from alkaline to neutral is efficiently converted into a phosphorus compound and nitrogen. Since at least one of the compounds is added and decomposed by the microorganisms supported on activated carbon, the activity of the microorganisms is increased, and the secondary by-products can be converted into nutrients without adding an organic substance which is a nutrient of the microorganisms. As a result, the increase in operating costs and the generation of excess sludge due to the addition of organic substances are reduced, and the volatile organic chlorine compounds are efficiently rendered harmless.

According to a second aspect of the present invention, there is provided the method for treating a volatile organic chlorine compound according to the first aspect, wherein the activated carbon has at least a portion of at least one of a phosphorus compound and a nitrogen compound. And a nitrogen-phosphorus supply filler containing

[0012] A nitrogen compound containing at least a phosphorus compound and / or a nitrogen compound at least partially.
Since activated carbon containing a phosphorus supply filler is used, there is no need to separately add at least one of a phosphorus compound and a nitrogen compound, and volatile organic chlorine compounds can be easily treated.

According to a third aspect of the present invention, in the method for treating a volatile organic chlorine compound, the activated carbon is bone charcoal.

Since bone charcoal is used as activated carbon, there is no need to separately add at least one of a compound and a nitrogen compound, and volatile organic chlorine compounds can be easily treated.

According to a fourth aspect of the present invention, there is provided the method for treating a volatile organic chlorine compound according to the second aspect, wherein the nitrogen-phosphorus supply filler is ammonium magnesium phosphate. .

Further, since ammonium magnesium phosphate is used as the nitrogen-phosphorus supply filler, for example, ammonium magnesium phosphate generated as sludge at the time of treating human waste can be used, and volatile organic chlorine compounds can be efficiently treated. .

According to a fifth aspect of the present invention, there is provided a method for treating a volatile organic chlorine compound according to any one of the first to fourth aspects, wherein the first by-product is contacted with water. In this case, the secondary by-product generated by circulating water is concentrated.

[0018] Since the secondary by-product generated by circulating water at the time of contact between the primary by-product and water is concentrated, the processing efficiency of the secondary by-product is improved. In addition, the processing cost of the secondary by-product is reduced.

The method for treating a volatile organic chlorine compound according to claim 6 is the method for treating a volatile organic chlorine compound according to any one of claims 1 to 5, wherein the water is obtained by extracting the volatile organic chlorine compound. It is sewage.

In order to reuse the wastewater from which the volatile organic chlorine compound has been extracted as the water which is brought into contact with the primary by-product to produce a readily decomposable secondary by-product, the bioactive carbon in the latter stage is used. By the treatment, the wastewater is treated together with the secondary by-product, and the water for contacting the primary by-product is not separately required, so that the efficiency of the treatment can be improved.

The apparatus for treating a volatile organic chlorine compound according to claim 7 is characterized in that the volatile organic chlorine compound is converted from wastewater containing at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene. Extracting means for extracting the volatile organic chlorine compound extracted by the extracting means, and irradiating the volatile organic chlorine compound with ultraviolet rays in the presence of oxygen in the presence of oxygen to oxidize and generate a hydrophilic primary by-product; A decomposing means for bringing the primary by-product into contact with water to hydrate it by this ultraviolet irradiation means to produce an easily decomposable secondary by-product; and a secondary by-product produced by this decomposing means. PH adjusting means for adjusting the pH of water containing the product to a range from alkaline to neutral,
An addition unit for adding at least one of a phosphorus compound and a nitrogen compound to water whose pH has been adjusted by the pH adjustment unit, and an activated carbon carrying microorganisms are accommodated. A biological activated carbon means for decomposing the secondary by-product contained in the water to which at least one of them is added by a microorganism carried on the activated carbon.

The volatile organic chlorine compound of at least one of dichloroethylene, trichloroethylene and tetrachloroethylene extracted from the wastewater by the extraction means is irradiated with ultraviolet rays in the presence of oxygen by ultraviolet irradiation means. Efficiently oxidizes to a hydrophilic primary by-product, and hydrates this primary by-product by contacting it with water whose pH has been adjusted from alkaline to neutral by a pH adjusting means by a decomposition means. To efficiently decompose easily produced secondary by-products by adding at least one of a phosphorus compound and a nitrogen compound by adding means and decomposing them by microorganisms supported on activated carbon of biological activated carbon means, The activity of microorganisms is increased, and secondary by-products are decomposed as nutrients without adding organic matter which is a nutrient source of the microorganisms separately. It reduces the growth and development of excess sludge, detoxifies efficiently volatile organic chlorine compounds.

[0023] The apparatus for treating a volatile organic chlorine compound according to claim 8 is the apparatus for treating a volatile organic chlorine compound according to claim 7, wherein the adding means contains at least one of a phosphorus compound and a nitrogen compound. A filling tank for supplying nitrogen-phosphorus, a filling tank, an inflow passage for allowing water whose pH has been adjusted by the pH adjusting means to flow into the filling tank, and an outflow passage for allowing water stored in the filling tank to flow to the biological activated carbon means. It is provided with.

The addition of at least one of the phosphorus compound and the nitrogen compound is carried out by adding water whose pH has been adjusted by pH adjusting means to nitrogen containing at least one of the phosphorus compound and the nitrogen compound through an inflow passage. -Flowing into the filling tank for the phosphorus-supplying filler, and allowing the water supplied with at least one of the phosphorus compound and the nitrogen compound from the nitrogen-phosphorus-supplying filler to flow out of the filling tank to the biological activated carbon means through the outflow passage. Therefore, at least one of a phosphorus compound and a nitrogen compound is supplied in a flow path in which water decomposed into a readily decomposable secondary by-product by contact with the primary by-product is discharged to the biological activated carbon means. In addition, the volatile organic chlorine compound is continuously treated, and the treatment efficiency is improved.

The volatile organic chlorine compound treatment apparatus according to the ninth aspect is characterized in that the volatile organic chlorine compound is converted from sewage containing at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene. Extracting means for extracting the volatile organic chlorine compound extracted by the extracting means, and irradiating the volatile organic chlorine compound with ultraviolet rays in the presence of oxygen in the presence of oxygen to oxidize and generate a hydrophilic primary by-product; A decomposing means for bringing the primary by-product into contact with water to hydrate it by this ultraviolet irradiation means to produce an easily decomposable secondary by-product; and a secondary by-product produced by this decomposing means. PH adjusting means for adjusting the pH of water containing the product to a range from alkaline to neutral,
At least a portion contains at least one of a phosphorus compound and a nitrogen compound, and contains a carrier that contains activated carbon and carries a microorganism, and degrades the secondary by-product generated by the decomposition means with the microorganism. Biological activated carbon means.

The volatile organic chlorine compound of at least one of dichloroethylene, trichloroethylene and tetrachloroethylene extracted from the sewage by the extraction means is irradiated with ultraviolet rays in the presence of oxygen by ultraviolet irradiation means. Efficiently oxidizes to a hydrophilic primary by-product, and hydrates this primary by-product by contacting it with water whose pH has been adjusted from alkaline to neutral by a pH adjusting means by a decomposition means. To efficiently decompose easily produced secondary by-products by adding at least one of a phosphorus compound and a nitrogen compound by adding means and decomposing them by microorganisms supported on activated carbon of biological activated carbon means, The activity of microorganisms is increased, and secondary by-products are decomposed as nutrients without adding organic matter which is a nutrient source of the microorganisms separately. It reduces the growth and development of excess sludge, detoxifies efficiently volatile organic chlorine compounds.

According to a tenth aspect of the present invention, there is provided the apparatus for treating a volatile organic chlorine compound according to the ninth aspect, wherein the carrier is bone charcoal.

Since bone charcoal is used as activated carbon, there is no need to separately add at least one of a phosphorus compound and a nitrogen compound, and volatile organic chlorine compounds can be easily treated.

[0029] The apparatus for treating a volatile organic chlorine compound according to claim 11 is the apparatus for treating a volatile organic chlorine compound according to claim 9 or 10, wherein the carrier contains ammonium magnesium phosphate.

Since a carrier containing ammonium magnesium phosphate is used, a phosphorus compound and a nitrogen compound are supplied while treating the secondary by-product from the carrier, and at least one of the phosphorus compound and the nitrogen compound is separately supplied. The configuration to add is unnecessary, and the processing efficiency is improved, and ammonium magnesium phosphate generated as sludge at the time of human waste treatment can be used, and the volatile organic chlorine compound is efficiently processed.

According to a twelfth aspect of the present invention, there is provided the apparatus for treating a volatile organic chlorine compound according to any one of the seventh to eleventh aspects, wherein the decomposition means comprises a primary by-product and water. And a closed circulation circuit for concentrating secondary by-products generated by circulating water with a circulating means at the time of contact with water.

Then, when the primary by-product and the water come into contact with the decomposing means, water is circulated by the circulating means to form the second by-product.
Since the secondary by-product to be produced is concentrated because the closed circulation circuit for concentrating the by-product is provided, the processing efficiency of the secondary by-product is improved, and the treatment of the secondary by-product is performed. Costs are reduced.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of a volatile organic chlorine compound processing apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an apparatus for treating a volatile organic chlorine compound.
Is provided with an extraction device 2 as extraction means. The extraction device 2 mixes volatile organic chlorine compounds such as dichloroethylene (CHCl = CHCl, CH ₂ = CCl ₂ ), trichloroethylene (CHCl = CCl ₂ ), and tetrachloroethylene (CCl ₂ = CCl ₂ ). An airtight extraction tank (not shown) is connected to the raw water pipe 3 into which sewage flows. The extraction device 2 includes an aeration unit (not shown) for aerating air, which is a gas containing oxygen, and dichloroethylene (CHCl = CHCl), which is a volatile organic chlorine compound mixed into sewage by aeration of air. , C
H ₂ = CCl ₂ ), trichloroethylene (CHCl = C
Cl ₂ ) or tetrachloroethylene (CCl ₂ = CC)
l ₂ ) is allowed to extract into the air. In addition, you may extract a volatile organic chlorine compound in sewage into air by vacuum deaeration using a deaeration means instead of an aeration means. Furthermore, the extraction device 2
Is connected to a drain pipe 4 from which sewage from which volatile organic chlorine compounds have been extracted flows out as primary treated water.

The extraction device 2 is provided with an ultraviolet irradiation tank (UV) as an ultraviolet irradiation means via a first air supply pipe 6.
(Irradiation tank) 7 is connected. This ultraviolet irradiation tank 7
An ultraviolet lamp (not shown) which is formed in an airtight structure such as a plug flow type and irradiates ultraviolet rays such as a xenon lamp, a low-pressure mercury lamp, and a high-pressure mercury lamp is provided. This ultraviolet lamp can be irradiated with ultraviolet rays having a wavelength of 300 nm or less, for example, a synthetic quartz glass tube lamp of 119 W or less, which emits ultraviolet rays having wavelengths of 185 nm and 254 nm, is made of synthetic quartz glass having impurities of 0.001% or less. And a glass tube (not shown) that transmits 50% or more of ultraviolet rays having a wavelength of 200 nm or less. And the extraction device 2
Irradiates the extracted volatile organochlorine compounds in the air with ultraviolet rays in the presence of oxygen in the air, thereby oxidatively decomposing primary by-products such as tetrachlorethylene (CCl ₂ ＣCCl). ₂ ) In the case of carbonyl chloride (COCl ₂ ) or trichloroacetyl chloride (C
Cl ₃ COCl: TCAA).

A decomposition means 10 is connected to the ultraviolet irradiation tank 7 via a second air supply pipe 9. The decomposition means 10 includes an absorption tank 11 to which the second air supply pipe 9 is connected, an absorption liquid tank 13 connected to the absorption tank 11 via a first water supply pipe 12 through which water can flow, and an absorption liquid tank Circulation pipe 14 provided with a pump (not shown) as a circulating means for circulating water in 13 to absorption tank 11
And

The absorption tank 11 is formed to have a corrosion-resistant structure so as not to be corroded by acidic water or the like. Also,
The absorption tank 11 is provided with an ejector (not shown) for mixing air containing primary by-products supplied from the second air supply pipe 9 with water circulating in the circulation pipe 14 in a gas-liquid manner. The first water supply pipe 12 and the circulation pipe 14 constitute a closed circulation circuit 15. Then, by contact of the primary by-product with water, dichloroacetyl chloride (Cl ₂ CHCOCl)
Represents dichloroacetic acid (CHCl ₂ C) as a secondary by-product
OOH: DCAA), and trichloroacetyl chloride (CCl ₃ COCl) dissolves as a secondary by-product, trichloroacetic acid (CCl ₃ COOH: TCAA). An exhaust pipe 16 for exhausting air from which primary by-products have been removed by contact with water is connected to the absorption tank 11.

On the other hand, the absorbing liquid tank 13 is also formed to have a corrosion resistant structure so as not to be corroded by acidic water or the like.
Then, the absorption liquid tank 13 detects the pH of the water containing the secondary by-product, and serves as a pH adjusting means for controlling the water to be in a range from alkaline to neutral, for example, weak alkaline of pH 7 to 8. A first pH controller 18 is provided. Further, the absorption liquid tank 13 is connected to a water supply pipe 19 as a water supply means for supplying water so that the stored water does not become less than a predetermined amount.

The absorption liquid tank 13 of the decomposition means 10 has a second
The biological activated carbon means 22 is connected via a water pipe 21.
The biological activated carbon means 22 includes a regulating tank 23 to which the second water pipe 21 is connected, a biological activated carbon tank 25 connected to the regulating tank 23 via a third water pipe 24, A return pipe 26 for returning a part of the water to the adjustment tank 23 is provided.

Then, the pH of the water containing the secondary by-product sent from the second water pipe 21 is detected in the adjusting tank 23 to detect the pH of the water from an alkaline to neutral range, for example, a weak alkaline pH range of 7 to 8. A second pH control device 27 is provided as a pH adjusting means for controlling the pH. The adjusting tank 23 has an NP adding device 28 as an adding means for adding at least one of a nitrogen compound and a phosphorus compound to the water containing the secondary by-products flowing in through the second water supply pipe 21. Is connected.

The biological activated carbon tank 25 contains a carrier (not shown) mainly composed of activated carbon and carrying microorganisms. The secondary by-products contained in the water flowing in through the third water pipe 24 are converted by microorganisms. Decompose. A discharge pipe 30 is connected to the biological activated carbon tank 25 of the biological activated carbon means 22 for discharging water in which the secondary by-product is decomposed as treated water.

Next, the processing operation of the volatile organic chlorine compound in the processing apparatus of the above embodiment will be described.

Soil containing dichloroethylene (CHCl = CHCl, CH ₂ = CCl ₂ ), trichloroethylene (CHCl = CCl ₂ ) or tetrachloroethylene (CCl ₂ = CCl ₂ ), which is a volatile organic chlorine compound, The water flows into the extraction device 2 through the raw water pipe 3, and air is diffused into the wastewater to volatilize volatile organic chlorine compounds in the wastewater into the air. Then, the air containing the volatile organic chlorine compound flows into the ultraviolet irradiation tank 7 through the first air supply pipe 6. Further, the sewage from which the volatile organic chlorine compounds have been removed is discharged through the drain pipe 4 and separately treated.

Next, an ultraviolet lamp (not shown) of the ultraviolet irradiation tank 7 is turned on, and the air containing the volatile organic chlorine compound which flows into the ultraviolet irradiation tank 7 from the extraction device 2 through the first air supply pipe 6 has a wavelength. Is irradiated with ultraviolet rays of 300 nm or less, particularly 200 nm or less for a predetermined time, for example, about 20 seconds. By the irradiation of the ultraviolet rays, almost all of the volatile organic chlorine compounds are converted to carbonyl chloride (CO 2) which is hydrophilic by oxygen in the air.
Cl ₂ ) and dichloroacetyl chloride (Cl ₂ CHCO)
Cl), trichloroacetyl chloride (CCl ₃ COC)
l), is oxidatively decomposed into primary by-products such as carbon monoxide (CO), carbon dioxide (CO ₂ ), and hydrogen chloride (HCl). Then, after irradiation with ultraviolet rays for a predetermined time, the ultraviolet irradiation tank 7
The air inside the vessel is passed through the second air supply pipe 9 to the absorption tank 11 of the decomposition means 10.
To the air.

On the other hand, a pump is driven into the absorption tank 11 to supply water from the absorption liquid tank 13 of the decomposing means 10 via the circulation pipe 14 together with air supplied through the second air supply pipe 9 by the ejector. It flows into the absorption tank 11. During the inflow of water through the ejector, the air containing the primary by-product is sucked into the circulating water so as to be entrained, and the air containing the primary by-product becomes fine bubbles. Water and gas-liquid mixing, absorption tank
Flow into 11. By this gas-liquid mixing, carbonyl chloride (COCl ₂ ) and carbon monoxide (C
O), carbon dioxide (CO ₂ ), hydrogen chloride (HCl) and the like are efficiently dissolved in water, and dichloroacetyl chloride (C
l ₂ CHCOCl) is dichloroacetic acid (CHCl ₂ COO).
H: DCAA), and trichloroacetyl chloride (CCl ₃ COCl) is dissolved in trichloroacetic acid (CCl 3
₃ COOH: TCAA) to form a secondary by-product. Note that a part of oxygen in the air is dissolved together. Further, by colliding with water that flows into the absorption tank 11 and is stored at the bottom of the absorption tank 11, primary by-products that flow into the absorption tank 11 without being completely dissolved by gas-liquid mixing by the ejector and Oxygen in the air is also entrained and dissolved in the water, and the water stored at the bottom of the absorption tank 11 is stirred.

Then, the second by-product is brought into contact with the second by-product.
The water containing the by-product flows into the absorption liquid tank 13 through the first water supply pipe 12. Since hydrogen chloride is dissolved in the water flowing into the absorption liquid tank 13, the first pH controller 18 controls sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO ₃ ), and sodium hydrogen carbonate (NaHC).
O ₃ ) and potassium hydroxide (KOH) are added to adjust the pH from almost neutral to slightly alkaline. Part of the water adjusted from almost neutral to slightly alkaline is
It is returned to the absorption tank 11 again via 14 and circulated. It should be noted that the water stored in the absorption liquid tank 13 is supplied from a water supply pipe 19 as appropriate, so that it does not become less than a predetermined amount.

The water in the absorbing liquid tank 13 is supplied to the second water pipe 21.
Through the control tank 23 of the biological activated carbon means 22. Then, the nitrogen compound and the phosphorus compound are added to the water flowing into the adjustment tank 23 by the NP addition device while being adjusted from substantially neutral to weakly alkaline by the second pH control means. Further, a regulating tank to which the nitrogen compound and the phosphorus compound are added.
The water in 23 flows into the biological activated carbon tank 25 via the third water pipe 24. And the second flowing into the biological activated carbon tank 25
The water containing the secondary by-products is partially desorbed and removed by the activated carbon of the carrier and decomposed by the microorganisms carried on the carrier using the secondary by-products as a carbon source. In other words, the water flowing into the biological activated carbon tank is dihaloacetic acid or trichloroacetic acid
Since it contains the harmless inorganic substance salt generated by the adjustment and harmless carbon dioxide gas and oxygen, the microorganism decomposes and absorbs haloacetic acid as a carbon source. As a result of the treatment of the microorganisms, the water circulating in the adjusting tank 23 and the biological activated carbon tank 25 in the return pipe 26 gradually contains only inorganic salt, carbon dioxide, and oxygen.

Then, part of the water in the biological activated carbon tank 25 is
The water is discharged through the discharge pipe 30 and is separately discharged as harmless treated water after being subjected to sewage treatment for removing salts and the like.

Next, the operation of the above embodiment will be described.

Tetrachloroethylene (CCl ₂ ＣCCl)
Trichloracetic acid (CCl ₃ COOH), which is a by-product formed by hydrophilizing ₂ ), has a theoretical oxygen demand of 0.0
Since it is 9g-O ₂ / g-TCAA and very low relatively persistent, to process in microorganisms must maintain activated sludge, maintaining the activated sludge in the other organic nutrient Source is required. Therefore, as shown in FIG. 6, a conventional activated sludge tank 31 made of activated sludge is provided with a CNP addition device 32 for supplying a carbon source, a nitrogen source and a phosphorus source, and a membrane separation device 33 for preventing outflow of the activated sludge. Was connected to the experimental apparatus 34.

That is, as shown in FIG.
Is connected to an extraction device 2 having an extraction tank having a drain pipe 4 to which a raw water pipe 3 is connected.
Connect. Further, the ultraviolet irradiation tank 7 has an absorption tank 11 provided with an exhaust pipe 16 and a water supply pipe 19 via a second air supply pipe 9.
Is connected, and the decomposition means 10 having the closed circulation circuit 15 including the first water supply pipe 12 and the circulation pipe 14 is connected to the absorption liquid tank 13 to which the first pH control device 18 is connected. The separation means 10 is connected to a second pH control device 27 and an activated sludge tank 31 to which a CNP adding device 32 for supplying a carbon source such as yeast extract, a nitrogen compound serving as a nitrogen source and a phosphorus compound serving as a phosphorus source is connected. With this activated sludge tank 31
An experimental device 34 is constructed by connecting a membrane separation device 33 to which a discharge pipe 30 is connected. Here, as the membrane separation device 33, one provided with a UF membrane having a molecular weight cut off of about 20,000 was used.

Then, the trichloracetic acid flowing into the activated sludge tank 31 whose sludge concentration was adjusted to about 4000 mg / liter was 4000 mg / liter, the residence time was 3 days, and the load of trichloroacetic acid was 0.33 g-TCAA / g VSSA.
/ Day, volume load is set to 1.3 kg-TCAA / m ³ / day, about twice the amount of yeast extract in BOD ratio with trichloroacetic acid is added from the CNP addition device 32, and the pH during activated sludge treatment is controlled by microorganisms. The activity of the activated sludge was automatically set to 7.5, the water temperature was kept at 30 ° C., and air was aerated at 15 liters / minute by an aeration device arranged at the bottom of the activated sludge tank.
FIG. 7 shows the result.

From the results shown in FIG. 7, trichloracetic acid was satisfactorily decomposed for 15 days while the yeast extract was added, and was hardly detected. However, the trichloroacetic acid was rapidly reduced after 15 days when the addition of the yeast extract was stopped. Acetic acid was detected, indicating that trichloroacetic acid was not decomposed by the microorganism. This indicates that the carbon source is indispensable not only for the growth of microorganisms but also for the decomposition of trichloroacetic acid. In this experimental device 34, a device for adding a nitrogen source and a phosphorus source, which are nutrient elements, in addition to the carbon source is also required. The configuration of the device becomes complicated and large, and three types of yeast extract, nitrogen source and phosphorus source are used. The addition of also increases operating costs. Furthermore, the addition of the yeast extract generates excess sludge, which requires a separate treatment of the excess sludge.

On the other hand, a treatment apparatus using the biological activated carbon of the present invention
The same experiment was performed using 41. As the processing device 41, FIG.
As shown in FIG. 1, the extraction device 2 to which the raw water pipe 3 is connected has the first
An ultraviolet irradiation tank 7 connected via an air supply pipe 6 is connected via a second air supply pipe 9 to a decomposition means 10 having an absorption tank 11, an absorption liquid tank 13 and a closed circuit circuit 15. Then, an adjusting tank 23 to which a second pH control device 27 and an NP adding device 28 were connected was connected to the decomposition means 10, and a biological activated carbon tank 25 was connected to the adjusting tank 23. Further, the drain pipe 4 connected to the extraction device 2 is connected to the absorption liquid tank 13 of the decomposing means 10, and the first treated water, which is the effluent from which the volatile organic chlorine compounds are extracted from the extraction device 2, is extracted. This was water to be brought into contact with air containing the primary by-product. Further, an exhaust pipe 16 for exhausting the air contacted with the sewage in the absorption tank 11 was connected to the adjusting tank 23, and a second exhaust pipe 42 was connected to the adjusting tank 23 to constitute a processing apparatus 41. Here, the volume of the activated carbon charged into the biological activated carbon tank 25 was 0.5 liter, and the contact time with the wastewater was about 10 minutes. The result is shown in FIG.

From the results shown in FIG. 3, trichloroacetic acid was hardly detected at the beginning of the passage of the water containing the secondary by-products into the biological activated carbon tank 25, but the adsorption capacity of the activated carbon almost disappeared thereafter. After about one month, the decomposition rate of trichloroacetic acid became about 80%. Thereafter, the load was reduced to 9.9 kg-TCAA / m ³ / day. As a result, the treatment was stably performed at a decomposition rate of 99% or more. As described above, although the volume load was slightly reduced, the treatment could be performed at substantially the same level without adding an organic substance and aerating the air in the biological activated carbon tank. That is, it is understood that the addition of an organic substance is not required, the apparatus configuration can be simplified, and the operating cost can be reduced.

Next, instead of the NP adding device 28 shown in FIG. 1, a nitrogen-phosphorus supply filler containing a nitrogen compound and a phosphorus compound is disposed in the middle of the flow of the wastewater, and the nitrogen compound is supplied during the flow of the wastewater. The same experiment was conducted with the processing apparatus 51 for supplying a phosphorus compound.

That is, the treatment device 51 is not provided with the NP addition device 28 in the adjusting tank 23 shown in FIG. 1, but is provided between the adjusting tank 23 and the biological activated carbon tank 25 in the third water supply pipe 24 shown in FIG. In parallel, it is connected to the regulating tank 23 through an inflow pipe 52 as an inflow path, and is connected to the biological activated carbon tank 25 through an outflow pipe 53 as an outflow path. An NP filling tank 54 is provided as an adding means filled with ammonium magnesium oxide. And the adjustment tank shown in FIG.
23, the biological activated carbon tank 25 is filled with 0.5 liter of activated carbon to make the contact time of water 15 minutes, and the NP filling tank 54 is filled with 0.01 liter of ammonium magnesium phosphate and brought into contact with water. The time was set to 0.3 minutes. Then, water containing 1000 mg / liter of dichloroacetic acid was flowed into the adjustment tank 23 at a condition of 0.48 liter / day, and the amount of circulation via the return pipe 26 from the biological activated carbon tank 25 to the adjustment tank 23 was reduced. The treatment was carried out at 48 liters / day with the concentration of dichloroacetic acid flowing into the adjusting tank 23 being 10 mg / liter. The result is shown in FIG.

From the results shown in FIG. 5, the water in the regulating tank 23 is directly sent to the biological activated carbon tank 25 through the third water pipe 24 without passing through the NP filling tank 54, and the water is supplied to the treatment apparatus 1 shown in FIG. In the same manner as in the case where the nitrogen compound and the phosphorus compound were not added by the NP addition device 28, chlorine was not detected in the running water and dichloroacetic acid was hardly detected until 4 days after the start of the operation. . For this reason, it is considered that dichloroacetic acid was adsorbed and removed by the adsorption capacity of activated carbon until the first four days. Further, from day 7, it was recognized that dichloroacetic acid was starting to be decomposed by microorganisms due to a chlorine balance, but the decomposition rate was about 52%. Therefore, as a result of switching the third water supply pipe 24 and circulating the NP filling tank to continue the treatment, decomposition is promoted, and
% Removal rate was observed.

Here, the dichloracetic acid substantially serving as the BOD source supplied is 111 mg-BOD / day, and the nitrogen concentration required to decompose this BOD is 5.5 mg / BOD.
On a day, the phosphorus concentration is 1.1 mg / day. However, when tap water containing no carbon source is used as the water to be contacted with the primary by-product, only about 0.5 mg / day of nitrogen concentration and about 0.0005 mg / day of phosphorus concentration can be obtained. From this, it is clear that the nitrogen and phosphorus sources are deficient.

Then, when treated by the treatment apparatus shown in FIG. 4, the nitrogen concentration in the treated water flowing out is about 0.3 mg.
/ Liter, phosphorus concentration was about 0.2 mg / liter. Therefore, by flowing the NP filling tank filled with ammonium magnesium phosphate, which is a nitrogen-phosphorus supply filler, insufficient nitrogen and phosphorus sources are supplied, and secondary by-products of volatile organic chlorine compounds are produced. It turns out that the thing is sufficiently processed.

Further, by flowing through the NP filling tank 54, a device for adding a nitrogen compound and a device for adding a phosphorus compound are unnecessary, and a simple structure for simply flowing water is provided.
Can be easily processed continuously.

As described above, at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene extracted from wastewater is irradiated with ultraviolet rays in the presence of oxygen to efficiently oxidatively decompose the first organic compound. PH of secondary by-products from alkaline to neutral
The easily decomposable secondary by-product formed efficiently by contacting with the adjusted water is decomposed by a microorganism supported on activated carbon by adding at least one of a phosphorus compound and a nitrogen compound. The secondary by-product can be decomposed as a carbon source without adding an organic substance which is a carbon source of microorganisms separately, and an increase in operation cost and generation of excess sludge due to the addition of the organic substance can be reduced, and efficient volatilization can be achieved. Harmful organic chlorine compounds.

Then, when the first by-product and the water come into contact with each other, water is circulated in the circulation pipe 14 to form a closed circulation circuit 15, and the produced second by-product is concentrated. The processing efficiency of the secondary by-product can be improved, and the processing cost of the secondary by-product can be reduced.

Further, NP filling of water whose pH has been adjusted by the second pH control device 27 through an inflow pipe 52 with ammonium magnesium phosphate which is a nitrogen-phosphorus supply filler containing a phosphorus compound and a nitrogen compound. By circulating through the tank 54, it is brought into contact with the primary by-products, and
Water decomposed into secondary by-products can be treated continuously, and treatment efficiency can be improved.

In the above embodiment, the NP addition device is provided and described. However, the carrier in the biological activated carbon tank contains:
For example, a nitrogen-phosphorus supply filler containing at least one of a phosphorus compound and a nitrogen compound, specifically, ammonium magnesium phosphate as a nitrogen-phosphorus supply filler such as a slow-acting fertilizer, or bone charcoal is mixed. May be. Further, bone charcoal may be used as activated carbon. According to these configurations, an apparatus for separately adding a neighboring compound or a nitrogen compound is not required, and can be used as a carrier for microorganisms, thereby reducing processing costs and improving processing efficiency.

As the water to be brought into contact with the air containing the primary by-products, sewage discharged as first treated water discharged from the drain pipe 4 may be used. According to this configuration,
When sewage contains organic matter, this organic matter is also treated in the biological activated carbon tank 25, so that treatment efficiency can be improved, and when it contains a nitrogen compound or a phosphorus compound, it is added to increase the activity of microorganisms. Since the amount of the nitrogen compound and the phosphorus compound added can be reduced, and the nitrogen compound and the phosphorus compound in the sewage are absorbed by the microorganism, the treatment cost can be reduced.

The first by-product is contacted with water by gas-liquid mixing using an ejector. However, the first by-product is aerated in water or the water is filled in a tank filled with the first by-product. And any gas-liquid mixing method such as spraying.

[0068]

According to the method for treating a volatile organic chlorine compound according to the first aspect of the present invention, oxygen is present in at least one of the volatile organic chlorine compounds extracted from sewage, such as dichloroethylene, trichloroethylene and tetrachloroethylene. The primary by-product oxidized by irradiating ultraviolet rays under the
A readily decomposable secondary by-product is produced by contacting with water whose pH has been adjusted to a range from alkaline to neutral, and this secondary by-product is added with at least one of a phosphorus compound and a nitrogen compound. Decomposed by the microorganisms supported on activated carbon, the activity of the microorganisms is increased, and the secondary by-products can be decomposed as a nutrient source without separately adding an organic substance serving as a nutrient source of the microorganism. Increase in cost and generation of excess sludge can be reduced, and volatile organic chlorine compounds can be efficiently made harmless.

According to the method for treating a volatile organic chlorine compound according to the second aspect, in addition to the effect of the method for treating a volatile organic chlorine compound according to the first aspect, at least a part of at least one of a phosphorus compound and a nitrogen compound. Since activated carbon containing a nitrogen-phosphorus supply filler containing either one of them is used, it is not necessary to separately add at least one of a phosphorus compound and a nitrogen compound, and the volatile organic chlorine compound can be easily treated.

According to the method for treating a volatile organic chlorine compound according to the third aspect, in addition to the effect of the method for treating a volatile organic chlorine compound according to the first aspect, since bone carbon is used as activated carbon,
There is no need to separately add at least one of the compound and the nitrogen compound, and the volatile organic chlorine compound can be easily treated.

According to the method for treating a volatile organic chlorine compound according to the fourth aspect, in addition to the effect of the method for treating a volatile organic chlorine compound according to the second aspect, ammonium magnesium phosphate is used as a nitrogen-phosphorus supply filler. Since it is used, for example, ammonium magnesium phosphate generated as sludge at the time of treating human waste can be used, and the volatile organic chlorine compound can be efficiently treated.

According to the method for treating a volatile organic chlorine compound according to the fifth aspect, in addition to the effect of the method for treating a volatile organic chlorine compound according to any one of the first to fourth aspects, a primary by-product and a volatile organic chlorine compound can be eliminated. In order to concentrate the secondary by-product generated by forming a closed circulation circuit by circulating water by the circulation means at the time of contact with water, while improving the processing efficiency of the secondary by-product, The processing cost of the secondary by-product can be reduced.

According to the method for treating a volatile organic chlorine compound according to the sixth aspect, in addition to the effect of the method for treating a volatile organic chlorine compound according to any one of the first to fifth aspects, a primary by-product and a volatile organic chlorine compound are eliminated. In order to reuse the sewage from which the volatile organochlorine compound has been extracted as water for generating a readily decomposable secondary by-product by contact, the second stage treatment with biological activated carbon is carried out.
The wastewater can be treated together with the secondary by-product, and the water for contacting the primary by-product is not separately required, so that the treatment efficiency can be improved.

According to the apparatus for treating volatile organic chlorine compounds according to claim 7, dichloroethylene extracted from wastewater,
A primary organic by-product oxidized by irradiating ultraviolet rays to at least one volatile organic chlorine compound of trichloroethylene and tetrachloroethylene in the presence of oxygen is brought into contact with water whose pH has been adjusted from alkaline to neutral. To produce a secondary by-product easily decomposable, and the secondary by-product is decomposed by a microorganism supported on activated carbon by adding at least one of a phosphorus compound and a nitrogen compound. The activity can be increased, the secondary by-product can be decomposed as a nutrient source without separately adding an organic substance serving as a nutrient source of microorganisms, and the increase in operation cost and the generation of excess sludge due to the addition of the organic substance can be efficiently reduced. Volatile organic chlorine compounds can be rendered harmless.

According to the apparatus for treating a volatile organic chlorine compound according to the eighth aspect, in addition to the effect of the apparatus for treating a volatile organic chlorine compound according to the seventh aspect, water whose pH has been adjusted by the pH adjusting means can be used. A nitrogen-phosphorus supply containing at least one of a phosphorus compound and a nitrogen compound is supplied to a filling tank for supplying a filler, and at least one of the phosphorus compound and the nitrogen compound is added. And at least one of a phosphorus compound and a nitrogen compound can be supplied in a flow path for allowing water decomposed into secondary decomposable by-products to flow out to a biological activated carbon means, thereby continuously treating volatile organic chlorine compounds. Processing efficiency can be improved.

According to the apparatus for treating volatile organic chlorine compounds according to the ninth aspect, dichloroethylene extracted from wastewater,
A primary organic by-product oxidized by irradiating ultraviolet rays to at least one volatile organic chlorine compound of trichloroethylene and tetrachloroethylene in the presence of oxygen is brought into contact with water whose pH has been adjusted from alkaline to neutral. To produce easily degradable secondary by-products, and to decompose the secondary by-products by microorganisms supported on activated carbon by adding at least one of a phosphorus compound and a nitrogen compound,
The activity of microorganisms can be increased, the secondary by-product can be decomposed as a nutrient source without adding an organic substance which is a nutrient source of the microorganism separately, and the increase in operation cost and the generation of excess sludge due to the addition of organic substances can be reduced, It is possible to efficiently detoxify volatile organic chlorine compounds.

According to the apparatus for treating a volatile organic chlorine compound according to the tenth aspect, in addition to the effect of the apparatus for treating a volatile organic chlorine compound according to the ninth aspect, since bone carbon is used as activated carbon, a phosphorus compound and a nitrogen compound are separately provided. There is no need to add at least one of the compounds, and the volatile organic chlorine compound can be easily treated.

According to the apparatus for treating a volatile organic chlorine compound according to the eleventh aspect, in addition to the effect of the volatile organic chlorine compound according to the ninth or tenth aspect, a carrier containing ammonium magnesium phosphate is used. The phosphorus compound and the nitrogen compound are supplied while treating the secondary by-product from the above, and a structure in which at least one of the phosphorus compound and the nitrogen compound is separately added becomes unnecessary, and the treatment efficiency can be improved, and for example, in the treatment of human waste In this case, ammonium magnesium phosphate generated as sludge can be used, and volatile organic chlorine compounds can be efficiently treated.

According to the apparatus for treating a volatile organic chlorine compound according to the twelfth aspect, in addition to the effect of the apparatus for treating a volatile organic chlorine compound according to any one of the seventh to eleventh aspects, the primary auxiliary secondary means can be added to the decomposition means. In order to provide a closed circulation circuit for concentrating the secondary by-product generated by circulating water by the circulation means at the time of contact between the product and water, the generated secondary by-product is concentrated. The processing efficiency of the secondary by-product can be improved, and the processing cost of the secondary by-product can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an apparatus for performing a method for treating a volatile organic chlorine compound of the present invention.

FIG. 2 is a block diagram showing another embodiment of the apparatus for performing the method for treating a volatile organic chlorine compound of the present invention.

FIG. 3 is a graph illustrating a processing status of the above.

FIG. 4 is a block diagram showing still another embodiment of the apparatus for performing the method for treating a volatile organic chlorine compound of the present invention.

FIG. 5 is a graph for explaining a processing state of the embodiment.

FIG. 6 is a block diagram showing an apparatus as a comparative control of the method for treating a volatile organic chlorine compound of the present invention.

FIG. 7 is a graph for explaining a processing state of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing apparatus of volatile organic chlorine compound 2 Extraction apparatus as extraction means 7 Ultraviolet irradiation tank as ultraviolet irradiation means 10 Decomposition means 14 Circulation pipe as circulation means 15 Closed circulation circuit 18 First pH control apparatus as pH adjustment means 22 Biological activated carbon means 27 Second pH control device as pH adjustment means 28 NP addition device as addition means 52 Inflow pipe as inflow path 53 Outflow pipe as outflow path 54 NP filling tank as addition means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 9/00 504 C02F 9/00 504A 1/32 1/32 1/58 1/58 A 3/10 3 / 10Z F term (reference) 4D003 AA01 AA12 AB12 BA02 CA10 DA07 DA08 EA25 FA01 FA04 FA06 4D037 AA11 AA14 AB14 BA18 BB09 CA01 CA07 CA11 CA14 4D038 AA08 AB14 BB06 BB07 BB13 BB16 BB19

Claims (12)

[Claims] 1. The volatile organic chlorine compound is extracted from wastewater containing at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene, and the extracted volatile organic chlorine compound is extracted. Is irradiated with ultraviolet rays in the presence of oxygen to oxidize to generate a hydrophilic primary by-product, and the primary by-product is converted into a pH range from alkaline to neutral.
Hydrated by contacting with the adjusted water to produce a readily decomposable secondary by-product, and adding at least one of a phosphorus compound and a nitrogen compound to water containing the secondary by-product. A method for treating a volatile organic chlorine compound, wherein the secondary by-product is decomposed by a microorganism supported on activated carbon. 2. The activated carbon according to claim 1, wherein the activated carbon contains a nitrogen-phosphorus feed filler containing at least one of a phosphorus compound and a nitrogen compound.
The method for treating a volatile organic chlorine compound according to the above. 3. The method for treating a volatile organochlorine compound according to claim 1, wherein the activated carbon is bone charcoal. 4. The method according to claim 2, wherein the nitrogen-phosphorus supply filler is ammonium magnesium phosphate. 5. The method according to claim 1, wherein the secondary by-product formed by circulating water when contacting the primary by-product with water is concentrated. A method for treating volatile organic chlorine compounds. 6. The method for treating a volatile organic chlorine compound according to claim 1, wherein the water is wastewater from which the volatile organic chlorine compound has been extracted. 7. Extraction means for extracting said volatile organic chlorine compound from sewage water containing at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene, and said extraction means Ultraviolet irradiation means for irradiating the volatile organic chlorine compound with ultraviolet light in the presence of oxygen to oxidize the volatile organic chlorine compound to produce a hydrophilic primary by-product; Means for contacting water with water to hydrate to form easily decomposable secondary by-products; and adjusting the pH of water containing secondary by-products generated by the decomposition means from alkaline to neutral PH adjusted to the range of pH
Adjusting means, adding means for adding at least one of a phosphorus compound and a nitrogen compound to water whose pH has been adjusted by the pH adjusting means, and accommodating activated carbon carrying microorganisms; And a biological activated carbon means for decomposing the secondary by-product contained in the water to which at least one of the nitrogen compound has been added by a microorganism carried on the activated carbon. Compound processing equipment. 8. The addition means includes a filling tank for supplying nitrogen-phosphorus containing at least one of a phosphorus compound and a nitrogen compound, and water whose pH has been adjusted by the pH adjusting means flows into the filling tank. The volatile organic chlorine compound treatment apparatus according to claim 7, further comprising an inflow passage for discharging the water stored in the filling tank and an outflow passage for flowing out the water to the biological activated carbon means. 9. Extraction means for extracting said volatile organic chlorine compound from sewage water containing at least one volatile organic chlorine compound of dichloroethylene, trichloroethylene and tetrachloroethylene, and said extraction means Ultraviolet irradiation means for irradiating the volatile organic chlorine compound with ultraviolet light in the presence of oxygen to oxidize the volatile organic chlorine compound to produce a hydrophilic primary by-product; Means for contacting water with water to hydrate to form easily decomposable secondary by-products; and adjusting the pH of water containing secondary by-products generated by the decomposition means from alkaline to neutral PH adjusted to the range of pH
Adjusting means, at least partially containing at least one of a phosphorus compound and a nitrogen compound and containing a carrier that contains activated carbon and carries a microorganism, and the secondary by-product generated by the decomposition means is An apparatus for treating volatile organic chlorine compounds, comprising: biological activated carbon means decomposed by microorganisms. 10. The apparatus for treating volatile organic chlorine compounds according to claim 9, wherein the carrier is bone charcoal. 11. The apparatus for treating a volatile organic chlorine compound according to claim 9, wherein the carrier contains magnesium ammonium phosphate. 12. The decomposing means includes a closed circulation circuit for concentrating a secondary by-product generated by circulating water by a circulating means at the time of contact between the first by-product and water. The apparatus for treating a volatile organic chlorine compound according to any one of claims 7 to 11, characterized in that: