JP6862680B2 - Water treatment system - Google Patents

Description

The present invention relates to an apparatus for removing and purifying organic compounds from water containing organic compounds (water to be treated, raw water), and in particular, an organic solvent from wastewater from various factories and research facilities, leachate from a final disposal site, groundwater, etc. It relates to an apparatus for removing organic compounds such as.

As an apparatus for purifying water containing an organic compound or the like, for example, an adsorption / desorption type water treatment apparatus described in Patent Document 1 is known. This water treatment device has an adsorption step in which water containing an organic compound is passed through an adsorption element to adsorb the organic compound, and then gas is supplied to the adsorption element on which the organic compound is adsorbed to adhere to the adsorption element. A purge (dehydration) step of removing the above-mentioned substances and a desorption step of supplying a high-temperature heating gas to desorb the organic compound adsorbed on the adsorbent element to regenerate the adsorbent element are carried out, and these steps are repeated. Therefore, while regenerating the adsorption element, water can be continuously purified basically without replacing the adsorption element.

In the water treatment apparatus of Patent Document 1, the organic compound adsorbed and removed by the adsorbing element is desorbed from the adsorbing element during regeneration and discharged as a gas containing the organic compound (desorbed gas). Here, when water vapor is used as the desorption medium (heating gas), it can be recovered as concentrated water containing a high concentration of organic compounds by liquefying and condensing the desorption gas, so that it also functions as a concentrator (for example, patent). Document 2 and Patent Document 3). Further, the concentrated water is secondarily treated by a secondary treatment device such as a combustion device or a wet oxidative decomposition device, and the organic compound is detoxified to complete the water treatment system.

By using the above concentrator in the water treatment system, the volume of water to be treated can be reduced and the concentration of organic compounds can be reduced. Therefore, the size of the system is larger than that in the case where the water to be treated is directly treated by the secondary treatment device. It has the effect of preventing water treatment and saving energy. In such a system, the above effect is enhanced by arranging a concentrator having a higher concentration ratio.

In the concentrators such as Patent Document 2 and Patent Document 3, dehydration is performed before the desorption step to remove the adhering water adhering to the adsorption element. By this dehydration step, the amount of water vapor required for desorption of the adsorbed water of the adsorption element is reduced, and the amount of the adhering water mixed in the concentrated water is reduced, so that the concentration ratio is increased. Therefore, if the dehydration efficiency of the adhering water can be improved, it can be said that the concentration ratio is increased.

Here, in the apparatus disclosed in Patent Documents 1 to 3, activated carbon fibers having a high adsorption rate and capable of removing organic compounds with high efficiency are used as suitable adsorption elements. Applicants have developed a non-woven fabric of activated carbon fiber with a large fiber diameter used as an adsorption element (Patent Document 4), and by applying it to the above-mentioned water treatment apparatus, it is possible to improve the dehydration efficiency (Patent Document 4). Patent Document 5).

Patent No. 4512993 JP-A-2014-217833 Japanese Patent Application 2015-120162 Patent No. 5250717 JP 2013-111551

As described above, from Patent Document 5, it can be said that making the activated carbon fibers constituting the non-woven fabric thicker is an effective means for increasing the dehydration efficiency and, as a result, improving the concentration ratio. However, from Patent Document 4, it can be seen that when the diameter of the activated carbon fiber is increased to more than 40 μm, the fibers are not entangled, the strength is lowered, and it is difficult to maintain the tissue structure as an adsorption element. Therefore, if an adsorption element having an activated carbon fiber diameter of more than 40 μm is used, problems such as breakage and fiber dropout may occur due to the above-mentioned filling of the processing tank of the concentrator and repeated suction and desorption operations. is there.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a concentrator filled with an adsorption element capable of suppressing breakage and falling off of fibers and improving the concentration ratio. The purpose is to provide a water treatment system that is compact and capable of water treatment with energy saving.

As a result of diligent studies, the present inventors have found that the above problems can be solved by the means shown below, and have arrived at the present invention. That is, the present invention has the following configuration.

1. 1. A water treatment system that removes and detoxifies the organic compound from the water to be treated containing the organic compound.
An adsorption step in which water to be treated containing an organic compound is passed through an adsorption element containing a structure of activated carbon fibers composed of a fiber bundle, the organic compound is adsorbed on the adsorption element, and the treated water is discharged. A dehydration step of ventilating the adsorbing element with gas to remove adhering water to the adsorbing element and a dehydration step of ventilating the adsorbing element with water vapor to desorb and then condense the organic compound adsorbed on the adsorbing element. A concentrator that repeatedly executes a desorption step of discharging concentrated water having a higher concentration of the organic compound than the water to be treated, a decomposition treatment device that decomposes the organic compound in the concentrated water discharged from the concentrator, and a decomposition treatment device. A water treatment system characterized by being equipped with.
2. A water treatment system for removing and detoxifying the organic compound from the water to be treated containing the organic compound, which is a tank filled with an adsorbent, and adsorbs the organic compound from the introduced water to be treated. A treatment tank that adsorbs to a material and discharges treated water, a gas vent that allows gas to be ventilated through the treatment tank to remove adhering water from the adsorbing element, and a gas venting part for desorbing the organic compound from the adsorbing element. A steam aeration unit for aerating water vapor through the treatment tank, and a concentration unit for concentrating the desorbed gas containing the organic compound desorbed from the adsorption element into concentrated water having a higher concentration of the organic compound than the water to be treated. A water treatment apparatus comprising a decomposition treatment apparatus for decomposing the organic compound in the concentrated water discharged from the concentration unit, wherein the adsorption element contains a structure of activated carbon fibers composed of a fiber bundle. system.
3. 3. The water treatment system according to 1 or 2 above, wherein the fiber bundle has a diameter of 100 to 600 μm.
4. The water treatment system according to any one of 1 to 3, further comprising a route for adsorbing the discharged water from the decomposition treatment device to the adsorption element.
5. The water treatment system according to any one of 1 to 4, further comprising a route for adsorbing the adsorbed water removed from the adsorption element to the adsorption element in the previous term.
6. The water treatment system according to any one of 1 to 5, wherein the structure is a woven fabric or a knitted fabric.
7. The water treatment system according to any one of 1 to 5, wherein the structure is a knitted material obtained by milling.
8. The decomposition treatment device includes an aeration device that aerates the concentrated water to volatilize the organic compound and discharges the organic compound as an aeration gas, and a gas combustion device that burns the aeration gas. The water treatment system according to any one of 1 to 7.
9. The description in any one of 1 to 7 above, wherein the decomposition treatment apparatus is a treatment apparatus for treating the concentrated water by using any one of a Fenton method, an accelerated oxidation method, and an electrolysis method. Water treatment system.

According to the above configuration of the present invention, it is possible to suppress breakage of the adsorption element and falling off of fibers, maintain the structure as an adsorption element, and improve the concentration ratio of the concentrator. Therefore, it is possible to provide a water treatment system capable of further downsizing the decomposition treatment device (secondary treatment device) for treating concentrated water and reducing the energy required for the decomposition treatment.

It is a figure which shows the structure of the water treatment system of one Embodiment of this invention. It is a figure which shows the example of (a) the structure structure of a knit, and (b) the example of the structure structure of a woven fabric in the adsorption element used for the concentrator of one embodiment of the present invention. It is a figure which shows an example of the decomposition treatment apparatus provided in the water treatment system of one Embodiment of this invention. It is a figure which shows another example of the decomposition treatment apparatus provided in the water treatment system of one Embodiment of this invention. It is a graph which shows an example of the tendency of reduction of ozone addition amount and organic substance concentration by the accelerated oxidation method. It is a graph which shows an example of the relationship between the processing efficiency (decomposition rate) of the accelerated oxidation method, and the required electric power.

Embodiments of the present invention will be described in detail.
The water treatment system according to the present invention is a water treatment system that removes and detoxifies the organic compound from the water to be treated containing the organic compound, and includes a concentrator and a decomposition treatment device.

In the concentrator according to the present invention, water to be treated containing an organic compound is passed through an adsorption element containing a structure of activated carbon fibers composed of fiber bundles, and the organic compound is adsorbed on the adsorption element for treatment. An adsorption step of discharging water, a dehydration step of aerating gas through the adsorbent to remove adhering water from the adsorbent, and an organic compound adsorbed by the adsorbent by aerating water vapor through the adsorbent. Is a device that repeatedly performs a desorption step of desorbing and then adsorbing and discharging concentrated water having a concentration of the organic compound higher than that of the water to be treated. With this configuration, water treatment can be continuously performed without exchanging the adsorption element.

Further, the concentrator according to the present invention can be said to have the following configuration. The concentrator according to the present invention is a tank filled with an adsorbent, and is composed of a processing tank in which the organic compound is adsorbed on the adsorbent from the introduced water to be treated and the treated water is discharged, and the adsorbing element. A gas venting unit that ventilates gas through the treatment tank to remove adhering water, a steam venting unit that ventilates water vapor through the treatment tank to desorb the organic compound from the adsorbing element, and desorption from the adsorbing element. It is an apparatus provided with a concentrating unit for concentrating the desorbed gas containing the organic compound in concentrated water having a concentration of the organic compound higher than that of the water to be treated.

A preferable structure of the concentrator is a concentrator that includes a plurality of adsorption elements and continuously performs adsorption, dehydration, and desorption by switching between the adsorption step, the dehydration step, and the desorption step with a damper or the like. Further, a concentrator having a structure in which the adsorption element is rotatably configured and the portion of the adsorption element that has adsorbed the organic compound in the adsorption step moves to the dehydration / desorption process by the rotation of the adsorption element is also preferable. Is.

The decomposition treatment apparatus according to the present invention is an apparatus for decomposing the organic compound in the concentrated water discharged from the concentrating device. One example is a processing device including an aeration device that aerates water containing an organic compound to volatilize the organic compound and discharges it as an aeration gas, and a gas combustion device that burns the aeration gas. Another example is a wet oxidative decomposition apparatus that treats water containing an organic compound using at least one of a Fenton method, an accelerated oxidation method, and an electrolysis method. The decomposition treatment device decomposes the organic compounds in the water and can purify the water.

Therefore, in the present embodiment, the damper switching type concentrator 100 shown in FIG. 1 will be described below as an example of the concentrator according to the present invention. Further, as an example of the decomposition treatment apparatus according to the present invention, there is a decomposition treatment apparatus 200A composed of the aeration apparatus 210 and the gas combustion apparatus 220 shown in FIG. 3, and a wet oxidation decomposition apparatus using the accelerated oxidation method shown in FIG. The differentiation processing apparatus 200B, which is the above, will be described.

FIG. 1 shows the configuration of the water treatment system 300 according to the embodiment of the present invention. As shown in FIG. 1, the water treatment system includes a concentrator 100 and a decomposition treatment device 200.

As shown in FIG. 1, the concentrator 100 has a first treatment tank 10 and a second treatment tank 20 filled with adsorption elements 11 and 12, respectively. The number of treatment tanks is not limited. Dampers, valves (valves V1 to V12) and the like are attached to the first treatment tank 10 and the second treatment tank 20, and the suction step, the dehydration step and the desorption step perform opening and closing operations of these dampers and valves. This is executed by controlling the flow path to be switched.

The adsorption elements 11 and 12 adsorb the organic compounds contained in the water to be treated by bringing them into contact with the water to be treated (raw water). In the concentrator 100, by supplying the water to be treated to the first treatment tank 10 from the water to be treated introduction line L1, the organic compound is adsorbed on the adsorption element 11, whereby the water to be treated is purified and the treated water discharge line. It is discharged as treated water through L2. Similarly, by supplying the water to be treated to the first treatment tank 20 from the water treatment water introduction line L1, the organic compound is adsorbed on the adsorption element 12, whereby the water to be treated is purified and passed through the treatment water discharge line L2. It is discharged as treated water.

The concentrating device 100 carries out a dehydration step of removing the adhering water adhering to the adsorption elements 11 and 12 by passing gas after the adsorption step. A gas flow is circulated from the gas supply line L5 to the first treatment tank 10 and the second treatment tank 20. By removing the adhering water by passing the gas, the subsequent desorption of the organic compound by the heating gas becomes easy.

Examples of the gas supplied in the dehydration step include air, nitrogen, an inert gas, and water vapor, but the gas is not particularly limited. It is preferable that the adhering water discharged in the dehydration step is returned to the water to be treated at the inlet of the concentrator 100 from the return water return line L6. This is because according to such a method, the number of steps can be omitted and it is efficient.

The concentrator 100 carries out a desorption step of desorbing the organic compounds adsorbed on the adsorption elements 11 and 12 by the flow of water vapor after the dehydration step. Steam flows through the first treatment tank 10 and the second treatment tank 20 from the heating gas supply line L3.

Examples of the steam supplied in the desorption step include steam and superheated steam obtained by heating the steam. The organic compound desorbed in the desorption step is mixed with water vapor and supplied as desorption gas to the cooler 30 through the desorption gas discharge line L4.

The cooler 30 is a device for cooling the desorbed gas. The desorbed gas is cooled by the cooler 30 and liquefied and condensed, and is discharged from the concentrating device 100 through the concentrated water discharge line L7 as water (concentrated water) containing the organic compounds desorbed from the adsorption elements 11 and 12. The cooling method of the cooler 30 is not particularly limited, but for example, a method of indirectly cooling the desorbed gas by using a refrigerant (cooling water, cold water, etc.) can be used. The concentrated water discharged from the concentrating device 100 through the concentrated water discharge line L7 is supplied to the decomposition treatment device 200 for processing. An example of the decomposition processing apparatus 200 will be described in detail later. The wastewater from the decomposition treatment device 200 may be returned to the water to be treated at the inlet of the concentrator 100 at the water return line L8.

In the concentrator 100, the adsorption element is divided into a plurality of (two in this case) treatment tanks and filled, and the treatment tank (adsorption tank) for performing the adsorption step and the treatment tank (desorption tank) for performing the dehydration and desorption steps are provided. It is configured to switch alternately. However, for example, the treatment tank is a single tank, the water to be treated is temporarily stored in a tank or the like during the dehydration and desorption steps, and the water to be treated that is temporarily stored in the next adsorption step is also adsorbed. There may be.

The adsorption elements 11 and 12 have a structure of activated carbon fibers composed of fiber bundles. Activated carbon fibers are used for the adsorption elements 11 and 12 from the viewpoint of performance. In other words, the activated carbon fiber has micropores on the surface and has a structure, so that the contact efficiency with water is high, and the adsorption rate of organic compounds in water is particularly high, which is extremely high compared to other adsorbents. Removal efficiency can be expressed.

The structure of the activated carbon fiber composed of the fiber bundles used for the adsorption elements 11 and 12 can be obtained by processing the fiber as a raw material into a structure described later, carbonizing and activating the fiber.

The fiber used as a raw material for the structure of the activated carbon fiber composed of the fiber bundles used for the adsorption elements 11 and 12 is not particularly limited, but a phenol fiber, a cellulosic fiber, an acrylonitrile fiber, and a pitch fiber are preferable. .. Among them, phenolic fibers are more preferable. This is because the yield of activated carbon fiber after carbonization and activation is high and the fiber strength is strong.

The phenolic fiber is a phenolic fiber obtained by spinning a mixture of a phenol resin mixed with at least one compound (composite) selected from the group consisting of fatty acid amides, phosphate esters, and celluloses. May be used as the raw yarn. This is because the fiber strength is further increased.

The structure of the activated carbon fiber composed of the fiber bundle is preferably a tissue structure formed of threads. It is more preferably knitted or woven. Compared to a non-woven fabric in which fibers are uniformly entwined, the structure is formed by yarn, so that the activated carbon fibers in the adsorption element have an appropriately coarse and dense structure, and the activated carbon fibers are regularly arranged. Therefore, a low pressure loss occurs, and as a result, the dehydration efficiency becomes high. Further, knitting is preferable. Compared to a woven fabric in which a grid-like structure is formed by interlacing warp and weft threads of the same length, a knitted fabric in which threads are knitted in the vertical or horizontal direction to form a structure has the above-mentioned coarse and dense structure. This is because it is easy, and the dehydration efficiency becomes higher due to the lower pressure loss. The structure of the activated carbon fiber composed of the fiber bundle is not limited to the above, and may be, for example, a sheet formed by hardening the yarn.

When the structure of the activated carbon fiber composed of the fiber bundle is a woven fabric, the structure of the woven fabric includes, and is not particularly limited, a single structure, a layered structure, a hair-attached structure, and an entangled structure. An example of a woven fabric is shown in FIG. 2 (b).

When the structure of activated carbon fiber composed of fiber bundles is a knit, the structure of the knit is classified into milling (rubber), tenjiku (flat), double-sided (pearl), and other knits. Examples include horizontal knits including tack and welt, vertical knits including chords, atlases, and knits that combine these knitting structures (for example, double ridges that combine milling and tuck). Although not particularly limited, milling knitting is preferable because it has an appropriate coarse and dense structure. An example of knitting is shown in FIG. 2 (a).

The thickness of the fiber bundle in the structure of the activated carbon fiber composed of the fiber bundles used for the adsorption elements 11 and 12 is preferably 100 to 600 μm. If it is less than 100 μm, the strength of the fiber bundle is lowered and there is a possibility that the tissue structure cannot be maintained as an adsorbent. If it exceeds 600 μm, a coarser and denser structure is formed, so that a short path of water to be treated occurs during the adsorption process. This is because the adsorption performance of the material may deteriorate. Here, the thickness of the fiber bundle can be obtained from the measurement of the diameter (thickness) of a plurality of places using the SEM photograph of the structure. It may be measured by another method.

Further, when a yarn is used as a fiber bundle, the yarn includes a single yarn formed by one yarn having a predetermined count, a twisted yarn formed by twisting two or more single yarns, and the like. It is not particularly limited as long as it fits in the thickness of the fiber bundle in the structure of the activated carbon fiber composed of the fiber bundle. The fineness of the raw material yarn is assumed to be 40th to 5th single yarn in cotton fineness, and twisted yarn (20th twin yarn, etc.) corresponding to the fineness, but the yarn diameter is increased by carbonization and activation. Since it shrinks, the fineness of the raw material may be any fineness within the range of the yarn diameter suitable for the structure of the activated carbon fiber.

Physical properties other than the above are not particularly limited in the structure of the activated carbon fiber composed of the fiber bundles used for the adsorption elements 11 and 12, but the BET specific surface area is 900 to 2500 m ² / g and the pore volume is 0. It is preferably 4 to 0.9 cm ³ / g and has an average pore diameter of 14 to 18 Å. When the BET specific surface area is ^{less than 900 m 2} / g, the pore volume is less than 0.4 cm ³ / g, and the pore diameter is less than 14 Å, the adsorption amount of the organic compound is low. When the BET specific surface area ^{exceeds 2500 m 2} / g, the pore volume exceeds 0.9 cm ³ / g, and the pore diameter exceeds 18 Å, the pore diameter increases and the adsorption capacity of organic compounds decreases. If the strength of the adsorption element is weakened and the cost of the material is high, it becomes uneconomical.

The organic compound contained in the water to be treated by the concentrator 100 is not particularly limited, but is not limited to aldehydes such as formaldehyde, acetaldehyde, propionaldehyde and achlorein, ketones such as methyl ethyl ketone, diacetyl, methyl isobutyl ketone and acetone, 1, Esters such as 4-dioxane, 2-methyl-1,3-dioxolane, 1,3-dioxolane, tetrahydrofuran, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, ethanol, n-propyl alcohol, isopropyl alcohol, butanol, etc. Alcohols, glycols such as ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, organic acids such as acetic acid and propionic acid, aromatic organic compounds such as phenols, toluene, xylene and cyclohexane, diethyl ether and allyl glycidyl ether. Ethers such as ethers, ditrils such as acrylonitrile, chlorine organic compounds such as dichloromethane, 1,2-dichloroethane, trichloroethylene, epichlorohydrin, N-methyl-2-pyrrolidone, dimethylacetamide, N, N-dimethylformamide Organic compounds, dioxins such as polydibenzoparadioxin (PCDD), polydibenzofuran (PCDF), dioxin-like polychloride biphenyl (DL-PCB), tetracycline, oseltamivir, oseltamivir phosphate, bezafibrate, triclosan and other antibiotics, Antilipidemia components such as bezafibrate and phenofibrate, antipyretic and analgesic components such as diclofenac, salicylic acid and acetaminophen, antiepileptic components such as carbamazepine, fumin substances such as fumic acid and fluboic acid, hexamethylenetetramine and diosmine. , 2-Methylisoborneol and the like are given as an example. The organic compound contained in the water to be treated by the concentrator 100 of the present embodiment may be one or more of these.

3 and 4 are block diagrams showing a decomposition treatment device 200A and a decomposition treatment device 200B, which are examples of the decomposition treatment device 200 provided in the water treatment system 300, respectively.

As shown in FIG. 3, the decomposition processing device 200A includes an aeration device 21 and a gas combustion device 22. This is a processing device that decomposes organic compounds by aerating the concentrated water discharged from the concentrating device 100 with the aeration device 21 to gasify the organic compounds and burning them with the gas combustion device.

The aeration device 21 is a device for processing the concentrated water discharged from the concentrating device 100 and supplied through the concentrated water discharge line L7, and is a gas supply device 212 for supplying bubble gas to the aeration tank 211 and the aeration tank 211. have. In the aeration tank 211, the supplied concentrated water comes into contact with the bubbles generated from the gas supply device 212, and the organic compounds in the concentrated water are transferred to the gas. The aeration tank 211 discharges water having a reduced concentration of organic compounds (aeration water) and aeration gas containing an organic compound. It is preferable that the aerated water is re-supplied as the water to be treated by the concentrator 100 through the water return line L8.

The gas combustion device 22 is a device for processing the aeration gas discharged from the aeration device 21. The gas combustion device 22 includes a heat exchanger 221 and a heating furnace 222. The aeration gas discharged from the aeration tank 21 is supplied to the gas combustion device 22 through the aeration gas discharge line 9L, the aeration gas is preheated by heat exchange in the heat exchanger 221 and at a predetermined temperature in the heating furnace 222. The processed gas purified by oxidatively decomposing the organic compound in the gas is discharged from the clean gas discharge line L10. The processing gas passes through the heat exchanger 221 and is heat-exchanged with the aeration gas, and then discharged to the outside of the device.

The type of the gas combustion device 22 is not particularly limited, but for example, an aerated gas using a direct combustion device that directly oxidatively decomposes an aerated gas at a high temperature of 650 to 800 ° C., a platinum catalyst, or the like. Efficient combination of a catalyst combustion device that oxidatively decomposes the heat, a heat storage type direct combustion device that economically directly oxidatively decomposes heat while recovering heat using a heat storage body, a platinum catalyst, etc. It is possible to use a heat storage type catalytic combustion device or the like that oxidatively decomposes the exposed gas by performing a catalytic oxidation reaction.

FIG. 4 is a diagram showing a configuration of a decomposition device 200B, which is another example of the decomposition processing device 200. The decomposition treatment apparatus 200B is a wet oxidative decomposition apparatus using an accelerated oxidation method in which the concentrated water discharged from the concentrating apparatus 100 is oxidatively decomposed by radicals generated in the apparatus.

As shown in FIG. 4, the decomposition device 200B includes a reaction tank 31. Further, as a device for generating radicals, one or more of an ozone generator 32, an ultraviolet lamp 33, and a drug supply device 34 is provided.
The agent referred to here is an oxidizing agent such as hydrogen peroxide. In the reaction tank 31, ozone, chemicals, ultraviolet rays, and the like are supplied to generate radicals such as hydroxyl radicals in the water, and the organic compounds in the concentrated water are decomposed by oxidative reaction with the radicals to obtain the concentration of the organic compounds. Discharges reduced water. Although not described in detail, devices using the Fenton method and the electrolysis method are also wet oxidative decomposition devices that oxidatively decompose organic compounds in water by emitting radicals.

The water (decomposed water) whose organic compound concentration has been reduced by being treated by the decomposition treatment device 200B is preferably re-supplied as the water to be treated by the concentration device 100 through the return water line L8.

FIG. 5 is a graph showing an example of a decreasing tendency of the organic compound concentration with respect to the amount of ozone added. As shown in FIG. 5, it is known that the amount of reduction of the organic compound is large at the initial stage of the start of the treatment, but the amount of reduction tends to decrease as the concentration of the organic compound decreases. Based on FIG. 5, an example of the relationship between the processing efficiency (decomposition rate) and the required power is shown in FIG. In response to the tendency shown in FIG. 5, a huge amount of electric power is required for high-efficiency processing. It is known that this tends to be the same for the aeration device 21. Therefore, when the organic compound is treated with high efficiency (for example, removal efficiency of 99.9% or more), the adsorption treatment is performed by the concentrator 100 rather than the removal efficiency of the decomposition treatment devices 200, 200A and 200B. Is efficient.
Therefore, the treated water (aerated water, decomposed water) of the decomposition treatment devices 200, 200A, and 200B can be removed to the same organic compound concentration as the water to be treated supplied to the concentration device 100, and has high removal efficiency. No need to process.

In the above-described embodiment described with reference to FIGS. 1 to 6, components such as a fluid transporting means such as a pump and a fan and a fluid storage means such as a storage tank are not shown for the sake of brevity. The elements may be arranged at appropriate positions as needed.

As described above, each of the above-described embodiments disclosed this time is an example in all respects and is not restrictive. The technical scope of the present invention is defined by the scope of claims and includes all modifications within the meaning and scope equivalent to the description of the scope of claims.

Examples will be shown below, and the present invention will be described in more detail. Each measurement of the example and the comparative example described later was carried out by the following method.

(Thickness of fiber bundle)
The fiber bundle thickness (diameter) was photographed with a scanning electron microscope (SEM), 100 fiber bundles were randomly selected from a large number of fiber bundles projected on the SEM image, and the fiber bundle diameter was measured. The average was taken as the diameter of the fiber bundle.

(BET specific surface area)
The BET specific surface area is a BET plot obtained by measuring the amount of nitrogen adsorbed on the sample when the relative pressure is increased in the range of 0.0 to 0.15 under the boiling point (-195.8 ° C.) atmosphere of liquid nitrogen. The surface area per unit mass of the sample (m ² / g) was determined by

(Pore volume)
The pore volume was measured by a gas adsorption method of nitrogen gas at a relative pressure of 0.95.

(Average pore size)
The average pore diameter was calculated by the following formula.
dp = 40,000 Vp / S (where dp: average pore size (Å))
Vp: Pore volume (cc / g)
S: BET specific surface area (m ² / g)

(Organic compound concentration)
The concentration of organic compounds in the water at the inlet and outlet of the device was analyzed and measured by gas chromatography.

(Amount of attached water)
The amount of adhering water was determined by measuring the weight of the adsorbent after the dehydration operation and using the following formula.
Adsorbed water content (g / g) = Adsorbent weight after dehydration operation (g) / Adsorbent weight when absolutely dry (g)

[Example 1]
In the first embodiment, as the water treatment system 300, a system including the concentration device 100 shown in FIG. 1 and the decomposition treatment device 200A composed of the aeration device 21 and the gas combustion device 22 shown in FIG. 3 is configured. .. Further, in the first embodiment, in the decomposition treatment apparatus 200A, a catalytic oxidation apparatus was used as the gas treatment apparatus 22, platinum was used as the catalyst, and an electric heater was used for heating.

First, a milled knitted yarn using a yarn having a cotton fineness of 20 counts using phenolic fibers is carbonized and activated to obtain a yarn (fiber bundle) having a yarn diameter (fiber bundle diameter) of 250 μm and a specific surface area of 1500 m ² /. An activated carbon fiber sheet (structure of activated carbon fiber composed of a fiber bundle) of g was prepared. Two adsorption elements in which 20 kg of the activated carbon fiber sheets were laminated were produced and installed in the treatment tanks 10 and 20 of the concentrator 100 shown in FIG. 1, respectively. The pore volume of the activated carbon fiber sheet was 0.60 cm ³ / g, and the average pore diameter was 15 Å.

In the adsorption step, raw water containing 500 mg / l of isopropyl alcohol was introduced at 3000 L / h. The isopropyl alcohol concentration of the treated water at that time was 0.5 mg / L or less, which was a good result that 99.9% or more could be removed.

Next, in the dehydration step, 0.1 MPa of water vapor was supplied, the water adhering to the adsorption element was dehydrated and removed, and the water vapor was returned to the raw water. The amount of adhering water at that time was 1.8 g / g as shown in Table 1 in the latter part.

Next, in the desorption step, 0.1 MPa of water vapor was supplied. The desorbed isopropyl alcohol and water vapor were liquefied and condensed in the cooler 30, and recovered as concentrated water. At that time, the amount of concentrated water was 120 L / h and the isopropyl alcohol concentration was 12500 mg / L, and it was found that the concentration was 25 times that of the raw water. After the desorption step was completed, each treatment tank moved to the adsorption step again and was repeatedly treated. In addition, each treatment tank was alternately subjected to a desorption step and an adsorption step.

Next, the recovered concentrated water was supplied to the decomposition treatment apparatus 200A shown in FIG. 3 for treatment. The concentrated water was supplied to the aeration tank 211 heated at 60 ° C. using steam, and recovered as aerated water that had been aerated. At that time, the isopropyl alcohol concentration of the aerated water was 500 mg / L or less. Further, the aerated water was returned to the raw water of the concentrator 100.

The aeration gas was supplied to the gas combustion device 22 and heated to 300 ° C., then oxidatively decomposed by a catalyst and discharged as clean air.

A series of treatments was carried out for 100 hours. Even after 100 hours, the outlet isopropyl alcohol concentration was 0.5 mg / L or less, which was a result of stable removal. As shown in Table 1 in the latter stage, the amount of water vapor required for desorption of the concentrator 100 is 105 kg / h, the amount of water vapor required for heating the aeration device 21 is 28 kg / h, and the electric heater required for heating the gas combustion device 22. The amount of electric power used was 20 kW.

[Example 2]
In the second embodiment, as the water treatment system 300, a system including a concentrator 100 shown in FIG. 1 and a decomposition treatment device 200B which is an accelerated oxidation device using the accelerated oxidation method shown in FIG. 4 is configured. Further, in the second embodiment, the decomposition treatment apparatus 200B is configured as an apparatus provided with an ozone generator 32 and a drug supply device 34 using hydrogen peroxide in addition to the reaction tank 31.

First, a milled knitted yarn using a yarn having a cotton fineness of 20 counts using phenolic fibers is carbonized and activated to obtain a yarn (fiber bundle) having a yarn diameter (fiber bundle diameter) of 250 μm and a specific surface area of 1500 m ² /. An activated carbon fiber sheet (structure of activated carbon fiber composed of a fiber bundle) of g was prepared. Two adsorption elements in which 20 kg of the activated carbon fiber sheets were laminated were prepared and installed in the treatment tanks 10 and 20 of the concentrator 100 in FIG. 1, respectively. The pore volume of the activated carbon fiber sheet was 0.60 cm ³ / g, and the average pore diameter was 15 Å.

In the adsorption step, raw water containing 5 mg / l of 1,4-dioxane was introduced at 8000 L / h. At that time, the outlet 1,4-dioxane concentration was 0.05 mg / L or less, which was a good result that 99.9% or more could be removed.

Next, in the dehydration step, 0.1 MPa of water vapor was supplied, the water adhering to the adsorption element was dehydrated and removed, and the water vapor was returned to the raw water. The amount of adhering water at that time was 1.8 g / g as shown in Table 1 in the latter part.

Next, in the desorption step, 0.1 MPa of water vapor was supplied. The desorbed 1,4-dioxane and water vapor were liquefied and condensed in the cooler 30, and recovered as concentrated water. At that time, the amount of concentrated water was 120 L / h, the concentration of 1,4-dioxane was 330 mg / L or more, and it was found that the concentration was 65 times or more that of the raw water. After the desorption step was completed, each treatment tank moved to the adsorption step again and was repeatedly treated. In addition, each treatment tank was alternately subjected to a desorption step and an adsorption step.

Next, the recovered concentrated water was supplied to the decomposition treatment apparatus 200B shown in FIG. 4 for treatment. Ozone from the ozone generator 32 and hydrogen peroxide from the chemical supply device 34 of the decomposition treatment apparatus 200B were supplied to the reaction tank 31, and the organic compounds in the concentrated water were oxidatively decomposed and recovered as decomposed water. The concentration of 1,4-dioxane in the recovered decomposed water was 5 mg / L or less. The recovered decomposed water was returned to the raw water of the concentrator 100.

A series of treatments was carried out for 100 hours. Even after 100 hours, the outlet 1,4-dioxane concentration was 0.05 mg / L or less, which was a result of stable removal. As shown in Table 1 in the latter stage, the amount of water vapor used for desorption of the concentrating device 100 was 105 kg / h, and the electric power required for ozone generation of the decomposition treatment device 200B of Example 2 was 0.6 kW.

[Comparative Example 1]
An adsorption element in which 20 kg of activated carbon fiber sheet, which is a phenolic fiber and is a non-woven fabric having a fiber diameter of 20 μm and a specific surface area of 1500 m ² / g, was laminated was prepared and installed in a concentrator having the same configuration as in FIG. In the adsorption step, raw water containing 500 mg / l of isopropyl alcohol was introduced at 3000 L / h. The isopropyl alcohol concentration of the treated water at that time was 0.5 mg / L or less, which was a good result that 99.9% or more could be removed.

Next, in the dehydration step, 0.1 MPa of water vapor was supplied, the water adhering to the adsorption element was dehydrated and removed, and the water vapor was returned to the raw water. The amount of adhering water at that time was 2.4 g / g as shown in Table 2 in the latter part.

Next, in the desorption step, 0.1 MPa of water vapor was supplied. The desorbed isopropyl alcohol and water vapor were liquefied and condensed in the cooler 30, and recovered as concentrated water. At that time, the amount of concentrated water was 170 L / h and the isopropyl alcohol concentration was 8800 mg / L, and it was found that the concentration was 17 times that of the raw water. After the desorption step was completed, each treatment tank moved to the adsorption step again and was repeatedly treated. In addition, each treatment tank was alternately subjected to a desorption step and an adsorption step.

Next, when the concentrated water was treated with the same decomposition treatment device 200A as in Example 1, the treatment performance was the same as that in Example 1.

A series of treatments was carried out for 100 hours. Even after 100 hours, the outlet isopropyl alcohol concentration was 0.5 mg / L or less, which was a result of stable removal. However, as shown in Table 2 in the latter stage, the amount of water vapor required for attachment / detachment of the concentrator of Comparative Example 1 is 125 kg / h, the amount of water vapor required for heating the aeration device 21 is 40 kg / h, and that of the gas combustion device 22. The amount of electric power used by the electric heater required for heating was 29 kW, which required processing energy as compared with Example 1.

[Comparative Example 2]
An adsorption element in which 20 kg of activated carbon fiber sheet, which is a phenolic fiber and is a non-woven fabric having a fiber diameter of 20 μm and a specific surface area of 1500 m ² / g, was laminated was prepared and installed in a concentrator having the same configuration as in FIG. In the adsorption step, raw water containing 5 mg / l of 1,4-dioxane was introduced at 1500 L / h. At that time, the outlet 1,4-dioxane concentration was 0.05 mg / L or less, which was a good result that 99.9% or more could be removed.

Next, in the dehydration step, 0.1 MPa of water vapor was supplied to dehydrate and remove the water adhering to the adsorption element. The amount of adhering water at that time was 2.4 g / g as shown in Table 2 in the latter part.

Next, in the desorption step, 0.1 MPa of water vapor was supplied. The desorbed 1,4-dioxane and water vapor were liquefied and condensed in a cooler and recovered as concentrated water. At that time, the amount of concentrated water was 170 L / h and the concentration of 1,4-dioxane was 235 mg / L, and it was found that the concentration was 47 times that of the raw water. After the desorption step was completed, each treatment tank moved to the adsorption step again and was repeatedly treated. In addition, each treatment tank was alternately subjected to a desorption step and an adsorption step.

Next, when the concentrated water was treated with the same decomposition treatment device 200B as in Example 2, the treatment performance was the same as that in Example 2.

A series of treatments was carried out for 100 hours. Even after 100 hours, the outlet isopropyl alcohol concentration was 0.5 mg / L or less, which was a result of stable removal. However, as shown in Table 2 in the latter stage, the amount of water vapor required for desorption of the concentrator of Comparative Example 2 is 125 kg / h, and the electric power required for ozone generation of the wet oxidative decomposition device 300 is 1 kW, which is higher than that of Example 2. Processing energy was required.

It should be noted that the above-disclosed embodiments and examples are all examples and are not restrictive. The technical scope of the present invention is valid depending on the scope of claims, and includes the description of the claims and the meaning equivalent to the description and all changes, modifications, replacements, etc. within the scope.

The concentrator according to the present invention can be suitably used for a device for removing organic compounds such as organic solvents from wastewater of various factories and research facilities, leachate of final disposal sites, groundwater, etc., and can greatly contribute to the industrial world. ..

10 1st treatment tank 20 2nd treatment tank 11, 12 Adsorption element 21 Aeration device 22 Gas combustion device 31 Reaction tank 100 Concentrator 200, 200A, 200B Decomposition treatment device 300 Water treatment system L1 Treatment water introduction line L2 Treatment water discharge Line L3 Heating gas supply line L4 Desorption gas discharge line L5 Gas supply line L6 Return water return line L7 Concentrated water discharge line L8 Return water line L9 Aeration gas discharge line L10 Clean gas discharge line V1 to V12 Valve

Claims (7)

A water treatment system that removes and detoxifies the organic compound from the water to be treated containing the organic compound.
A tank filled with an adsorption element, and a treatment tank in which the organic compound is adsorbed on the adsorption element from the introduced water to be treated and the treated water is discharged.
A gas aeration unit that allows gas to be aerated in the treatment tank to dehydrate and remove adhering water from the adsorption element.
A water vapor aeration unit that allows water vapor to be aerated in the treatment tank in order to desorb the organic compound from the adsorption element.
A concentrating unit that concentrates the desorbed gas containing the organic compound desorbed from the adsorbing element into concentrated water having a higher concentration of the organic compound than the water to be treated.
A decomposition treatment device for decomposing the organic compound in the concentrated water discharged from the concentrating unit is provided.
The suction device is seen containing a structure of the activated carbon fibers of fiber bundle, water treatment system, wherein the structure is a knitted fabric. The water treatment system according to claim 1, wherein the fiber bundle has a diameter of 100 to 600 μm. The water treatment system according to claim 1 or 2, further comprising a route for adsorbing the discharged water from the decomposition treatment device to the adsorption element. The water treatment system according to any one of claims 1 to 3, wherein the adsorbing element is provided with a route for adsorbing the adsorbed water removed from the adsorbing element. The water treatment system according to any one of claims 1 to 4 , wherein the structure is a knitted material obtained by milling. The decomposition treatment device includes an aeration device that aerates the concentrated water to volatilize the organic compound and discharges the organic compound as an aeration gas, and a gas combustion device that burns the aeration gas. The water treatment system according to any one of Items 1 to 5. Any one of claims 1 to 5 , wherein the decomposition treatment apparatus is a treatment apparatus for treating the concentrated water using any one of a Fenton method, an accelerated oxidation method, and an electrolysis method. The water treatment system described in.

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