JP5551628B2 - Method and apparatus for treating wastewater containing organic chemicals - Google Patents

Description

  The present invention relates to a method and apparatus for treating wastewater containing organic chemicals, and more specifically, to reuse wastewater containing organic chemicals such as dimethyl sulfoxide (DMSO). The present invention relates to a processing method for processing as an object, and an apparatus for performing such processing.

  In recent years, DMSO has been used as a peeling and cleaning agent in the electronics industry. For this reason, it is required to decompose DMSO, and for this request, for example, a biological treatment method for DMSO as disclosed in Patent Document 1 has been developed by the present applicant.

Japanese Patent No. 2776973

  According to such a biological treatment method, although DMSO can be decomposed | disassembled suitably, when the density | concentration of DMSO becomes high or the amount of waste_water | drain increases, the load concerning a biological treatment tank will increase correspondingly.

  As a result of the increased load on the biological treatment tank as described above, the biological treatment tank to be processed becomes larger and requires an installation space, and the energy consumed for the treatment also increases. Moreover, surplus sludge will also increase.

  The present invention has been made to solve such problems, and can significantly reduce the load applied to the biological treatment tank, thereby reducing the size of the biological treatment tank and reducing the installation space. It is possible to reduce energy consumption and excess sludge, and to recycle organic chemicals contained in wastewater such as DMSO.

In order to solve such problems, the present invention has been made as a method and apparatus for treating organic chemical-containing wastewater. The feature of the method for treating organic chemical-containing wastewater is that organic chemical-containing wastewater is treated as follows. 1 water is passed through the reverse osmosis membrane device 4 to obtain a permeate separated by the first reverse osmosis membrane device 4, and after obtaining a waste water containing tetramethylammonium hydroxide and the permeate, The mixed waste water is biologically treated, the treated water after biological treatment is further separated by the second reverse osmosis membrane device 14 and the concentrated liquid separated by the first reverse osmosis membrane device 4 is recovered. The organic chemical is dimethyl sulfoxide.

Moreover, the characteristic as a processing apparatus of organic chemical | medical agent containing waste_water | drain contains the 1st reverse osmosis membrane apparatus 4 which lets an organic chemical | medical agent containing waste water flow, and isolate | separates into a concentrate and a permeate, and tetramethylammonium hydroxide. A mixing tank (5) for mixing the wastewater and the permeate separated by the first reverse osmosis membrane device (4), a biological treatment device 6 for biologically treating the mixed wastewater obtained by the mixing, That is, the treatment device is configured by the second reverse osmosis membrane device 14 that separates the treated water biologically treated by the biological treatment device 6 into a concentrate and a permeate. The organic chemical is dimethyl sulfoxide.

In such a case, the evaporative concentration apparatus 19 is provided in the subsequent stage of the first reverse osmosis membrane device 4, the concentrated liquid separated in the first reverse osmosis membrane device 4, can be further concentrated by evaporation.

  In the present invention, the organic chemical-containing wastewater is passed through the reverse osmosis membrane device, the permeate separated by the reverse osmosis membrane device is biologically treated, and the concentrated solution separated by the reverse osmosis membrane device is recovered. Since it is a method, organic chemicals such as DMSO can be suitably decomposed by biological treatment and can be discharged out of the system in a very low concentration, while organic chemicals such as DMSO can be concentrated at a high concentration. Thus, there is an effect that useful organic chemicals such as DMSO can be recovered and reused.

  Therefore, useful organic chemicals such as DMSO that are newly used for cleaning and the like are not wasted, and the amount used can be reduced, resulting in a reduction in cost. .

  Furthermore, organic chemical-containing wastewater is not directly biologically treated, but is separated in advance by a reverse osmosis membrane device and biologically treated in a state where the concentration is diluted as a permeate after the separation. The biological treatment apparatus can be reduced in size, the installation space can be reduced, and the energy consumption and the amount of excess sludge can be reduced.

  Further, when the concentrated solution separated by the reverse osmosis membrane device is further collected by evaporation, the concentration of the collected concentrated solution can be further increased and reuse can be achieved more effectively. .

1 is a schematic block diagram of an organic chemical-containing wastewater treatment apparatus according to an embodiment. The schematic side view of a biological treatment apparatus. The front view of the fluid carrier of one embodiment.

  Hereinafter, with regard to an embodiment of the present invention, first, the configuration of a wastewater treatment apparatus containing DMSO as an example of an organic chemical will be described with reference to the drawings.

  In FIG. 1, 1 is a raw water storage tank for storing DMSO-containing wastewater, which is raw water, 2 is a heat exchanger for heating raw water supplied from the raw water storage tank 1, and heats steam, hot water, etc. It is a medium. Reference numeral 3 denotes a cartridge filter for filtering the heated raw water.

  Reference numeral 4 denotes a reverse osmosis membrane device for separating the raw water filtered by the cartridge filter 3 and from which the solid content and the like are removed into a concentrated solution and a permeated solution.

  5 is a mixing tank for mixing the permeated liquid separated by the reverse osmosis membrane device 4 and organic wastewater other than DMSO. As other organic wastewater, in this embodiment, tetramethylammonium is used. Organic rinse wastewater containing hydroxide (TMAH), isopropyl alcohol (IPA) or the like is used. The mixing tank 5 is configured to be supplied with condensed water from the condensed water storage tank 21.

  6 is a biological treatment apparatus for biologically treating the mixed wastewater of the DMSO-containing wastewater separated by the reverse osmosis membrane device 4 and the organic rinse wastewater, and in this embodiment, a fixed bed and a fluidized bed. A biological treatment apparatus equipped with both is used.

  That is, as shown in FIG. 2, the biological treatment apparatus 6 has a structure in which a fluidized bed 8 is provided on the upper part of the fixed bed 7. The fluidized bed 8 includes a pH adjusting pump or the like (not shown). Is provided. Further, a pipe 23 for agitating and agitating is provided in the fixed bed 7 portion.

  The fixed bed 7 and the fluidized bed 8 are filled with a fixed carrier and a fluidized carrier, respectively. As the fixed carrier, an entirely spherical porous ceramic material is used. The particle size of the fixed carrier is 5 to 10 mm.

  Further, as shown in FIG. 3, the flow carrier 9 has, on the front side, an arc-shaped peripheral portion 11 connected continuously around a substantially cross-shaped central portion 10, and a plurality of (this embodiment) is provided around the peripheral portion 11. In the form, eight fins 12 are formed so as to protrude at equiangular intervals, and the side surface is formed in a substantially rectangular shape, although not shown.

  The specific gravity of the fluid carrier 9 is 0.90 to 1.20, and the length in side view is about 10 mm. When the flow carrier 9 is formed in such a shape including the central portion 10, the peripheral portion 11, and the fins 12, the entire surface area of the flow carrier 9 is increased, so that microorganisms are easily attached. The material of the fluid carrier 9 can be arbitrarily selected from ordinary synthetic resins such as polypropylene and polyethylene.

  A microfiltration membrane device 13, a reverse osmosis membrane device 14, and an ultraviolet irradiation device 15 are further arranged downstream of the biological treatment device 6.

  16 is a recovered water storage tank for recovering recovered water which is separated and permeated by the microfiltration membrane device 13 and the reverse osmosis membrane device 14 and in which a small amount of TOC (total organic carbon) is oxidized and decomposed by the ultraviolet irradiation device 15. Thus, the recovered water recovered in the recovered water storage tank 16 is supplied to a pure water plant or the like as will be described later.

  Reference numeral 17 denotes an evaporation apparatus for evaporating and concentrating the concentrated liquid separated by the reverse osmosis membrane apparatus 14 at the latter stage.

  18 is a concentrated liquid storage tank for storing the concentrated liquid separated by the preceding reverse osmosis membrane device 4, and 19 is an evaporative concentration for further concentrating the concentrated liquid in the concentrated liquid storage tank 18 by heating and evaporation. In the apparatus, a heat exchanger 20 is provided between the concentrated liquid storage tank 18 and the evaporative concentration apparatus 19.

  As the heat medium of the heat exchanger 20, the vapor evaporated by the evaporative concentration device 19 is used.

  Reference numeral 21 denotes a condensed water storage tank for storing the steam used for heat exchange in the heat exchanger 20 as condensed water.

  Reference numeral 22 denotes a concentrated liquid recovery tank for recovering the concentrated liquid concentrated by the evaporative concentration apparatus 19.

  An embodiment of a method for treating DMSO-containing wastewater using an apparatus having such a configuration will be described. First, DMSO-containing wastewater discharged from a factory or the like flows into the raw water storage tank 1.

  The DMSO-containing waste water that is the raw water in the raw water storage tank 1 is first supplied to the heat exchanger 2 to be heated and filtered by the cartridge filter 3. The solid content and the like are removed by the cartridge filter 3.

  Next, the DMSO-containing wastewater filtered by the cartridge filter 3 is supplied to the reverse osmosis membrane device 4 and separated into a concentrate and a permeate. The concentrated liquid is obtained by concentrating the DMSO-containing wastewater that is the raw water as it is, and the permeate is obtained by diluting the DMSO-containing wastewater that is the raw water as it is.

  The permeate separated by the reverse osmosis membrane device 4 is supplied to the mixing tank 5. The mixing tank 5 is supplied with the organic rinsing waste water as described above, which is another factory effluent, and the permeated liquid containing DMSO and the organic rinsing waste water are mixed in the mixing tank 5. Further, condensed water is also supplied from the condensed water storage tank 21 to the mixing tank 5 and mixed with the DMSO-containing permeate and organic rinse waste water.

  The mixed waste water of the DMSO-containing permeate and the organic rinse waste water mixed in the mixing tank 5 is supplied to the biological treatment device 6 and biologically treated.

  More specifically, the mixed wastewater of DMSO-containing permeate and organic rinse wastewater supplied to the biological treatment device 6 reaches from the fluidized bed 8 to the fixed bed 7 and from the fixed bed 7 to the outside of the biological treatment device 6. Is discharged to the next process.

  In this fluidized bed 8, DMSO and other organic substances are decomposed, and highly active cells are produced.

  This highly active microbial cell will be captured by the fixed bed 7 and the biological activity of the fixed bed will also be improved.

  Next, the treated water biologically treated in the biological treatment tank 6 is filtered by the microfiltration membrane device 13 and further separated into concentrated water and permeated water by the reverse osmosis membrane device 14.

  The permeated water separated by the reverse osmosis membrane device 14 is supplied to the ultraviolet irradiation device 15, and a small amount of TOC is oxidatively decomposed and then recovered as recovered water in the recovered water storage tank 16.

  The recovered water recovered in the recovered water storage tank 16 is then supplied to a pure water plant or the like and used for producing pure water.

  The concentrated liquid separated by the reverse osmosis membrane device 14 is supplied to the evaporation device 17 and evaporated and concentrated. The concentrated liquid concentrated here contains sulfate ions and the like.

  On the other hand, the concentrate separated by the upstream reverse osmosis membrane device 4 is supplied to the concentrate storage tank 18 and further supplied to the evaporation concentration device 19.

  Before being supplied to the evaporative concentrator 19, the concentrated liquid is heated by the heat exchanger 20, and the vapor evaporated by the evaporative concentrator 19 as described above is used as the heat medium of the heat exchanger 20.

  The condensed water produced | generated here is supplied to the condensed water storage tank 21, and is returned to the mixing tank 5 from the condensed water storage tank 21. FIG.

Further, the concentrated liquid concentrated by the evaporative concentration device 19 is supplied to the concentrated liquid storage tank 22. As a result, a high concentration of DMSO is recovered.
The recovered DMSO can be reused as a chemical by further purification.

  In the above embodiment, the evaporation concentration device 19 that evaporates by heating is used as the evaporation concentration device 19 that concentrates the concentrate separated by the reverse osmosis membrane device 4, but the means for evaporation is based on the heating of the embodiment. Not limited to the evaporation means, for example, an evaporation means using reduced pressure or an evaporation means using vacuum may be used.

  Furthermore, in this embodiment, since the concentrate separated by the reverse osmosis membrane device 4 is further concentrated by the evaporation concentration device 19 and the concentrate is recovered, the concentrate having a high concentration of organic chemicals to be reused can be recovered. However, the provision of such an evaporating and concentrating device 19 is not an essential condition for the present invention.

  Furthermore, in the said embodiment, since the treated water after biological treatment was isolate | separated and permeate | transmitted with the microfiltration membrane apparatus 13 or the reverse osmosis membrane apparatus 14, the preferable effect that most suspended substances and salts in treated water can be removed. Although obtained, it is not an essential condition for the present invention to use such a microfiltration membrane device 13 or a reverse osmosis membrane device 14.

  Further, in the above embodiment, as the fluid carrier 8 filled in the fluidized bed 8, the arc-shaped peripheral part 11 is continuously provided around the central part 10 having a substantially cross shape, and a total of eight parts are provided around the peripheral part 11. However, the shape of the flow carrier 9 is not limited to this.

  For example, the number of fins 12 may be four, eight, ten, twelve, sixteen, twenty, etc., and the number is not limited. Further, the formation of the fins 12 is not an essential condition for the present invention, and it is possible to use a carrier without the fins 12.

  However, the formation of the fins 12 has an advantage that the fluid carrier 8 is easily rotated, and as a result, the fluidity of the fluid carrier 8 is improved. From the viewpoint of both such fluidity and ease of molding, the number of fins 12 is preferably about 8 to 20.

  On the other hand, if the shape of the central portion 10 becomes too complicated, clogging may occur. Therefore, it is desirable to select the shape of the central portion 10 by taking into consideration both the size of the surface area and the problem of clogging.

  Further, the shape of the peripheral portion 11 is not limited to the frontal substantially circular shape formed in the arc shape of the above embodiment, and may be, for example, a substantially rectangular shape or a substantially octagonal shape.

  However, by forming the shape of the peripheral portion 11 in a substantially circular shape, there is an advantage that the fluid carrier 8 is easily rotated, and thereby the fluidity of the fluid carrier 8 is improved.

  In any case, regarding the shape of the fluid carrier 8, the size of the surface area as described above, the fluidity associated with the ease of rotation of the fluid carrier 8, clogging, ease of molding with a mold, etc. are comprehensive. It is desirable to select the shape of the central portion 10 and the peripheral portion 11, the number of fins 12, the shape and the like after taking into account the above.

  Furthermore, the size of the fluid carrier 8 is preferably in the range of 0.1 to 3.0 cm, but is not limited thereto.

  Further, the material is not limited to the synthetic resin, but it is preferably made of a material that allows microorganisms to adhere appropriately and maintain as high a concentration as possible.

  However, it is particularly preferable when it is formed of a synthetic resin because it is easy to mold and the carrier can be produced economically.

  Further, the shape of the fixed carrier is not limited to the substantially spherical shape of the above embodiment, and the material is not limited to the ceramic of the embodiment. However, it is desirable to use a porous carrier as the fixed carrier.

  The particle size of the fixed carrier is not questioned, but is preferably 5 to 10 mm as in the above embodiment.

  Further, by filling the fluidized bed 8 or the fixed bed 7 with the carrier, a preferable effect that the amount of the bacterial cells in the biological treatment tank 6 can be increased is obtained. However, such a carrier is filled. However, this is not an essential condition for the present invention, and it is also possible to employ a floating sludge method without using a carrier.

  Furthermore, in the said embodiment, although the biological treatment tank 6 which has arrange | positioned the fluidized bed 8 to the upper part of the fixed bed 7 was used, it is also possible to use the biological treatment tank 6 which comprised only the fluidized bed or only the fixed bed. . However, in order to make the processing efficiency suitable, it is desirable to arrange the fluidized bed 8 on the upper part of the fixed bed 7 and pass water in a downward flow.

  Furthermore, although the said embodiment demonstrated the case where the organic rinse waste water containing TMAH, IPA, etc. was mixed with DMSO containing waste water, it contains 4th ammonia compounds other than TMAH, amines, such as monoethanolamine, etc. It is also possible to mix the waste water.

In the present invention, waste water containing such a fourth ammonia compound and amines is mixed with DMSO-containing waste water (more specifically, a permeate that has passed through a reverse osmosis membrane). The quaternary ammonia compound or amine can be used as a nitrogen source for the treatment of DMSO-containing wastewater, and therefore the DMSO-containing wastewater and the treatment of the quaternary ammonia compound or amines contained in the waste liquid itself As a result, it was possible to obtain the preferable effect of simultaneously carrying out the steps .

  Furthermore, in the said embodiment, after storing raw | natural water in the raw | natural water storage tank 1, the raw | natural water was supplied to the heat exchanger 2 and the cartridge filter 3, but the waste_water | drain discharged | emitted from a factory is stored in the raw | natural water storage tank 1, for example. It is also possible to supply directly to the heat exchanger 2 or the cartridge filter 3 without using it.

  The present invention is mainly applied to DMSO-containing wastewater as in the above embodiment, but wastewater containing organic chemicals other than DMSO and DMSO to other organic chemicals such as mono It is also possible to apply the present invention to wastewater mixed with ethanolamine or the like.

  Examples of the present invention will be described below.

  DMSO-containing wastewater having a concentration of 3100 ppm was treated at 380 m <3> / day. The amount of DMSO processed was 1180 kg / day. The total organic carbon (TOC) concentration of this waste water was 960 ppm, and the TOC amount was 365 kg / day.

  As another organic rinsing waste water that mixes DMSO-containing waste water with the permeate permeated through a reverse osmosis membrane, 1200 m 3 / day-containing TMAH and IPA-containing waste water was used. The amount of TOC was 144 kg / day. Of the 380 m 3 / day DMSO-containing waste water, the amount of permeate separated by the reverse osmosis membrane 4 was 358 m 3 / day and the amount of the concentrated liquid was 22 m 3 / day.

  The DMSO concentration in the permeate was 530 ppm, and the amount of DMSO in the permeate was 190 kg / day. The amount of TOC is 60 kg / day.

  On the other hand, the DMSO concentration in the concentrate was 4.5%, and the amount of DMSO in the concentrate was 990 kg / day. The concentrated solution was further heated and concentrated, and the amount of the recovered solution recovered for reuse was 1.6 m 3 / day, and the DMSO concentration was 60%.

  4: Reverse osmosis membrane device, 6: Biological treatment device, 19: Evaporation concentration device

Claims (4)

The organic chemical-containing wastewater is passed through the first reverse osmosis membrane device (4) to obtain a permeate separated by the first reverse osmosis membrane device (4), and the wastewater containing tetramethylammonium hydroxide and the permeation are obtained. After the mixed wastewater containing the liquid is obtained, the mixed wastewater is biologically treated, and the treated water after biological treatment is further separated by the second reverse osmosis membrane device (14), and the first reverse osmosis membrane device (4) A method for treating organic chemical-containing wastewater, wherein the concentrated liquid separated in step (b) is collected, and the organic chemical is dimethyl sulfoxide.   The method for treating organic chemical-containing wastewater according to claim 1, wherein the concentrated liquid separated by the first reverse osmosis membrane device (4) is further concentrated by evaporation. In the first reverse osmosis membrane device (4) for passing the organic chemical-containing wastewater and separating it into a concentrated solution and a permeate, the wastewater containing tetramethylammonium hydroxide and the first reverse osmosis membrane device (4) A mixing tank (5) for mixing the separated permeate, a biological treatment device (6) for biological treatment of the mixed waste water obtained by the mixing, and a biological treatment in the biological treatment device (6). And a second reverse osmosis membrane device (14) that separates the treated water into a concentrated solution and a permeate, and the organic chemical is dimethyl sulfoxide.   The evaporative concentration device (19) for further evaporating and concentrating the concentrated liquid separated by the first reverse osmosis membrane device (4) is provided on the rear stage side of the first reverse osmosis membrane device (4). The wastewater treatment equipment containing organic chemicals as described.

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