JP6690197B2 - Method and system for treating wastewater containing organic matter - Google Patents

Description

  The present invention relates to a method and a system for treating wastewater containing organic matter.

Industrial wastewater and domestic wastewater are reused as industrial water or discharged to rivers, etc., after being subjected to a treatment to remove suspended substances, organic substances, etc. contained in the wastewater.
As a method for treating industrial wastewater and the like, for example, in Patent Document 1, industrial wastewater is supplied to a reverse osmosis membrane (RO membrane) module using a reverse osmosis membrane and separated into permeated water and non-permeated water, There is disclosed a method for concentrating waste water by further supplying the non-permeated water to an evaporative concentrator to condense it.
However, in the treatment method of Patent Document 1, when wastewater containing organic matter (in particular, wastewater containing high-concentration organic matter) is treated, the organic matter contained in the wastewater causes clogging of the reverse osmosis membrane or the reverse osmosis membrane. There was a problem such as melting.

JP, 2007-789, A

As a method for treating wastewater containing organic matter, membrane separation that combines biological treatment that biodegrades organic matter by the action of microorganisms in activated sludge and membrane treatment that obtains treated water that has undergone solid-liquid separation by a separation membrane and permeates the separation membrane There is an activated sludge treatment (MBR) method.
The MBR method is an effective means for treating wastewater containing organic matter, but has the following problems when treating wastewater containing high-concentration organic matter.
That is, the higher the concentration of the organic matter contained in the wastewater, the longer the time required for the biological treatment for biodegrading the organic matter. Therefore, in order to treat wastewater containing high-concentration organic matter by the MBR method, it is necessary to retain the wastewater in activated sludge for a long time and perform biological treatment. On the other hand, new wastewater is sequentially discharged from factories and households. Therefore, when wastewater is retained in activated sludge in the MBR process for a long time for biological treatment, new wastewater cannot be supplied to the MBR process during that time, and the amount of wastewater discharged from factories and households and the MBR method Therefore, the balance with the amount of waste water treated cannot be maintained.
In order to avoid this, it is conceivable to form a large activated sludge tank for biological treatment in the MBR process to increase biological treatment per unit time, but in this case, the wastewater treatment system cannot be constructed compactly. .

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a wastewater treatment method and a treatment system capable of treating wastewater containing organic matter (in particular, wastewater containing high-concentration organic matter) in a well-balanced manner by the MBR method. And

The present invention has the following aspects.
[1] Evaporative separation step of subjecting wastewater containing organic matter to evaporative concentration treatment or distillation treatment to separate the solution A in which the organic matter is concentrated and the solution B in which the concentration of the organic matter is reduced, and the solution B. And a membrane separation activated sludge treatment step for obtaining treated water by treatment by a membrane separation activated sludge treatment method.
[2] Evaporation of wastewater containing an organic substance having a boiling point of 100 ° C. or higher under normal pressure by evaporative concentration to separate a solution A in which the organic substance is concentrated and a solution B in which the concentration of the organic substance is reduced. A method for treating wastewater containing organic matter, comprising: a separation step; and a membrane separation activated sludge treatment step of treating the solution B by a membrane separation activated sludge treatment method to obtain treated water.
[3] Evaporative separation in which wastewater containing an organic substance having a boiling point under atmospheric pressure of less than 100 ° C. is subjected to a distillation treatment to separate a solution A in which the organic substance is concentrated and a solution B in which the concentration of the organic substance is reduced. A method for treating wastewater containing organic matter, comprising: a step; and a step of treating the solution B by a membrane separation activated sludge treatment method to obtain treated water.
[4] The method for treating wastewater containing organic matter according to any one of [1] to [3], wherein the treated water is reused.
[5] Further, the treated water is filtered through a reverse osmosis membrane or a nanofiltration membrane, and a filtrate that has passed through the reverse osmosis membrane or the nanofiltration membrane and concentrated water that does not pass through the reverse osmosis membrane or the nanofiltration membrane. The method for treating wastewater containing organic matter according to any one of [1] to [3], which comprises a filtration separation step of separating into.
[6] The method for treating wastewater containing organic matter according to [5], wherein the filtrate is reused.
[7] The method for treating wastewater containing organic matter according to [5] or [6], characterized in that the concentrated water is returned to the evaporative separation step.
[8] The organic matter according to any one of [1] to [7], wherein the wastewater containing the organic matter has a total organic carbon (TOC) concentration of 2,000 to 50,000 mg / L. Waste water treatment method including.
[9] The organic matter contained in the wastewater containing the organic matter contains at least one compound selected from N, N-dimethylacetamide, N-methyl-2-pyrrolidone and N, N-dimethylformamide. The method for treating wastewater containing the organic substance according to any one of [1] to [8].
[10] An evaporative separator that evaporates and concentrates wastewater containing organic matter to separate it into a solution A in which the organic matter is concentrated and a solution B in which the concentration of the organic matter is reduced, and the solution B. And a membrane separation activated sludge treatment device for obtaining treated water by treating by a membrane separation activated sludge treatment method.
[11] The treatment system for wastewater containing organic matter according to [10], further comprising a treated water flow path for reusing the treated water.
[12] Furthermore, the treated water is filtered through a reverse osmosis membrane or a nanofiltration membrane, and a filtrate that has passed through the reverse osmosis membrane or the nanofiltration membrane and concentrated water that does not pass through the reverse osmosis membrane or the nanofiltration membrane. The wastewater treatment system containing an organic matter according to [10], characterized in that the wastewater treatment system is equipped with a filtration separation device.
[13] The wastewater treatment system containing an organic matter according to [12], further comprising a filtrate flow path for reusing the filtrate.
[14] The treatment system for wastewater containing organic matter according to [12] or [13], further comprising a concentrated water return passage for returning the concentrated water to the evaporation / separation device.
[15] The organic matter according to any one of [10] to [14], wherein the wastewater containing the organic matter has a total organic carbon (TOC) concentration of 2,000 to 50,000 mg / L. Wastewater treatment system including.
[16] The organic matter contained in the wastewater containing the organic matter contains at least one compound selected from N, N-dimethylacetamide, N-methyl-2-pyrrolidone and N, N-dimethylformamide. , [10] to [15] a wastewater treatment system containing the organic matter.

  According to the wastewater treatment method and treatment system of the present invention, wastewater containing organic matter can be treated in a well-balanced manner by the MBR method. In particular, it can be optimally used as a method and a method for treating wastewater containing high-concentration organic matter.

1 is a schematic configuration diagram showing an embodiment of a wastewater treatment system of the present invention. It is a schematic block diagram which shows other embodiment of the waste water treatment system of this invention. It is a schematic block diagram which shows other embodiment of the waste water treatment system of this invention.

  Hereinafter, the wastewater treatment method of the present invention will be described with reference to exemplary embodiments. However, the present invention is not limited to the following embodiments.

<First embodiment>
FIG. 1 is a schematic configuration diagram of a treatment system 1 used in a method for treating wastewater containing organic matter according to the first embodiment of the present invention.
The treatment system 1 evaporates and concentrates waste water containing an organic substance to separate it into a solution A in which the organic substance is concentrated and a solution B in which the concentration of the organic substance has been reduced, and A membrane-separated activated sludge treatment device 20 that obtains treated water by treating the solution B water by a membrane-separated activated sludge treatment (MBR) method.

(Evaporation separator 10)
The evaporative separator 10 includes an evaporative separator 11.
The evaporative separator 10 is supplied with wastewater from a raw water tank 41 in which wastewater containing organic matter is stored, and a solution A flow for discharging the solution A in which the organic matter is concentrated from the evaporative separator 11. The path 13 and the solution B flow path 14 for discharging the solution B having the reduced concentration of the organic substance from the separator 11 are connected to each other.

The evaporative separator 11 is not particularly limited as long as it is capable of evaporating wastewater containing an organic substance and separating it into a solution A in which the organic substance is concentrated and a solution B in which the concentration of the organic substance is reduced.
Examples of the evaporative separator 11 include a single-effect or multiple-effect method, a self-vapor compression method, a multi-stage flash method, and a liquid film flow-down method.

(Membrane separation activated sludge treatment device 20)
The membrane separation activated sludge treatment device 20 includes an activated sludge tank 21, an air diffusing pipe 22 arranged near the bottom of the activated sludge tank 21, and a separation membrane module arranged in the activated sludge tank 21 and above the air diffusing pipe 22. 25, and. The membrane separation activated sludge treatment device 20 is connected to a treated water flow passage 26 for discharging treated water from the device 20 and an excess sludge flow passage 28 for discharging excess sludge from the device 20.
A blower 23 that supplies air to the air diffuser 22 and an air introduction pipe 24 that connects the air diffuser 22 and the blower 23 are connected to the air diffuser 22.
A suction pump 27 is provided in the treated water channel 26 in the middle of the channel. The suction pump 27 can reduce the pressure in the separation membrane module 25, and the activated sludge and the treated water (permeate) are separated into solid and liquid. Further, the treated water is discharged to the outside of the activated sludge tank 21 through the treated water channel 26.

As the separation membrane module 25, a known separation membrane module including a known separation membrane (filtration membrane) can be used.
As the type of separation membrane, a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane) is preferable.
Examples of the shape of the separation membrane include a hollow fiber membrane, a flat membrane, a tubular membrane, and a bag-shaped membrane. Of these, hollow fiber membranes are preferred because they allow a high degree of integration of the membrane area when compared on a volume basis.

  Examples of the material of the separation membrane include organic materials (cellulose, polyolefin, polysulfone, polyvinyl alcohol, polymethylmethacrylate, polyvinylidene fluoride, polytetrafluoroethylene, etc.), metals (stainless steel, etc.), inorganic materials (ceramics, etc.). To be The material of the separation membrane is appropriately selected according to the properties of wastewater containing organic substances.

The pore size of the separation membrane may be appropriately selected according to the purpose of treatment. In the membrane separation activated sludge treatment method, the pore size of the separation membrane is preferably 0.001 to 3 μm. If the pore size is less than 0.001 μm, the resistance of the film tends to increase. If the pore size exceeds 3 μm, the activated sludge cannot be completely separated, and the water quality of the treated water (permeate) may deteriorate. The pore diameter of the separation membrane is more preferably 0.04 to 1.0 μm in the range of the microfiltration membrane.
One separation membrane module 25 may be arranged in the activated sludge tank 21, or a plurality of separation membrane modules 25 may be arranged.

  In the membrane separation activated sludge treatment device 20, a separation membrane unit in which the air diffuser 22 and the separation membrane module 25 are integrated may be used. Examples of such a separation membrane unit include the separation membrane unit described in JP2013-202524A.

  In the method of treating wastewater using the treatment system 1 shown in FIG. 1, a wastewater containing organic matter is subjected to an evaporative concentration treatment or a distillation treatment in an evaporative separation device 10 to reduce the concentration of the solution A in which the organic matter is concentrated and the concentration of the organic matter. The method includes an evaporative separation step of separating the solution B into a treated solution B, and a step of treating the solution B by a membrane separation activated sludge treatment device 20 by a membrane separation activated sludge treatment (MBR) method to obtain treated water.

(Wastewater containing high-concentration organic matter)
In the present invention, “wastewater containing high-concentration organic matter” means wastewater containing organic matter at a higher concentration than the wastewater containing organic matter generally treated by the MBR method, and for example, total organic carbon (TOC) concentration is 2 Waste water of 1,000 mg / L or more. The lower limit of the TOC concentration in the wastewater containing high-concentration organic matter in the present invention is preferably 2,000 mg / L or more, more preferably 3,000 mg / L or more, and further preferably 4,000 mg / L or more. The upper limit of the TOC concentration in the wastewater containing the high-concentration organic matter in the present invention is not particularly limited, but is preferably 50,000 mg / L or less, more preferably 40,000 mg / L or less, still more preferably 30,000 or less. When the TOC concentration in the wastewater containing high-concentration organic matter is within the above-mentioned preferable range, the effect of the present invention is easily obtained.
The wastewater treated by the treatment system of the present invention is not particularly limited as long as it can be separated into the solution A in which the organic matter is concentrated and the solution B in which the concentration of the organic matter is reduced by the evaporative separation step. Examples of the wastewater include factory wastewater (chemical, pharmaceutical, papermaking, beverage, oil, semiconductor, electronic, etc.), domestic wastewater, livestock wastewater, and the like.
Before being supplied to the evaporative separation device 10, the wastewater containing high-concentration organic matter may be subjected in advance to a treatment of removing coarse floating substances, earth and sand, etc. from the wastewater, a treatment of adjusting the pH, and the like.

(Evaporative separation process)
In the evaporative separation step, first, the wastewater containing the organic matter stored in the raw water tank 41 is supplied to the evaporative separation apparatus 10 through the wastewater flow path 12.
Next, in the evaporative separation device 10, a separation operation of evaporating the wastewater containing organic matter by the evaporative separator 11 to separate the solution A in which the organic matter is concentrated and the solution B in which the concentration of the organic matter is reduced is performed. Done.
In the above separation operation, the following (i) evaporative concentration treatment or (ii) distillation treatment is performed depending on the boiling point of the organic matter contained in the wastewater containing the organic matter.

(I) Evaporative Concentration Treatment In the evaporative concentration treatment, waste water containing an organic substance having a boiling point of 100 ° C. or higher under normal pressure is evaporated, and this is separated into a condensed fraction that is condensed and an evaporation residue that is not evaporated, In this process, the condensed component is recovered as a solution B having a reduced concentration of organic substances, and the evaporation residue is recovered as a solution A having concentrated organic substances.
(Ii) Distillation treatment In the distillation treatment, wastewater containing an organic substance having a boiling point under atmospheric pressure of less than 100 ° C. is evaporated, and this is separated into a condensed fraction that is condensed and an evaporation residue that is not evaporated, In this process, the components are recovered as a solution A in which organic substances are concentrated, and the evaporation residue is recovered as a solution B in which the concentration of organic substances is reduced.
The above-mentioned (i) evaporative concentration treatment and (ii) distillation treatment are appropriately selected according to the boiling points of the organic substances contained in the wastewater.
In the case of waste water containing both an organic substance having a boiling point of 100 ° C. or more under normal pressure and an organic substance having a boiling point of less than 100 ° C. under normal pressure, the waste water is evaporated and condensed with condensed components. , And the evaporation residue that has not evaporated is separated. Then, one having a concentration of organic matter lower than that of the wastewater before the evaporation treatment may be recovered as the solution B, and one having a concentration of organic matter higher than that of the wastewater before the evaporation treatment may be recovered as the solution A.
In addition, the solution B may be any solution that has a lower organic matter concentration than the organic matter concentration in the wastewater before the separation operation. For example, even when the organic matter contained in the wastewater is azeotroped with water and the like and the solution B after the separation operation contains the organic matter in the wastewater, the concentration of the organic matter in the solution B is the same as that before the separation operation. If it is lower than the organic matter concentration, the wastewater treatment method of the present invention can be applied.

The solution B separated by the above separation operation is transferred to the membrane separation activated sludge treatment device 20 in which the membrane separation activated sludge treatment step is performed, through the solution B flow path 14.
The solution A separated by the above separating operation is discharged through the solution A flow path 13 and stored in a solution A storage tank (not shown). This solution A may be treated as industrial waste.

(Membrane separation activated sludge treatment process)
In the membrane separation activated sludge treatment step of obtaining treated water by treating with the membrane separation activated sludge treatment method, first, the solution B separated in the evaporation separation step passes through the solution B flow path 14 and the membrane separation activated sludge treatment apparatus 20. Is supplied to the activated sludge tank 21.

In the activated sludge tank 21, the biological treatment is performed on the solution B by operating the blower 23 to introduce air from the air diffuser 22 and supplying oxygen to the microorganisms in the activated sludge.
Further, in the activated sludge tank 21, the suction pump 27 is operated to reduce the pressure inside the separation membrane module 25, so that solid-liquid separation is performed into activated sludge and treated water (permeated water). At this time, by introducing air from the air diffuser 22 into the separation membrane module 25, solid-liquid separation can be efficiently performed while cleaning the surface of the separation membrane (for example, hollow fiber membrane) of the separation membrane module 25. .

The treated water separated by the separation membrane module 25 is discharged through the treated water channel 26. This treated water can be reused as industrial water (for example, cooling water for various boilers, process water such as solvent for cleaning liquid), or discharged directly to the outside, but it can reduce environmental load and effectively use water resources. It is preferably reused from the point. By reusing the treated water, it is possible to provide a treatment method and a treatment system in which wastewater is not discharged outside (ZLD: zero liquid discharge).
The surplus sludge separated by the separation membrane module 25 is discharged through the surplus sludge flow path 28 and stored in a surplus sludge storage tank (not shown). Since the excess sludge contains microorganisms, a part of the excess sludge may be returned to the activated sludge tank 21 of the membrane separation activated sludge treatment device 20 and used again for biological treatment of the solution B. Also, excess sludge may be treated as industrial waste.

In the first embodiment of the present invention described above, the evaporative separation step is performed before the membrane separation activated sludge treatment (MBR) step, so that the MBR step is performed on the solution B having a reduced organic matter concentration. Be seen. Therefore, it is not necessary to retain the solution B in the activated sludge of the MBR process for a long time to perform biological treatment. As a result, a good balance is maintained between the amount of waste water discharged from factories and homes and the amount of waste water processed in the evaporative separation process and the MBR process.
Furthermore, it is not necessary to form a large activated sludge tank in the MBR process, and a wastewater treatment system containing organic matter can be constructed compactly. The first embodiment of the present invention can be suitably used particularly for treating wastewater containing high-concentration organic matter.

<Second embodiment>
Next, a method for treating wastewater containing organic matter according to the second embodiment of the present invention will be described. In the embodiments described below, the components corresponding to those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
FIG. 2 is a schematic configuration diagram of the processing system 2 used in the processing method of this embodiment. The treatment system 2 is provided with a filtration separation device 30 for filtering the treated water discharged from the device 20 with a reverse osmosis membrane or a nanofiltration membrane, on the downstream side of the membrane separation activated sludge treatment device 20, except for the first embodiment. The configuration is the same as that of the processing system 1 described above.

The filtration separation device 30 includes a filtration device 31 including a reverse osmosis membrane or a nanofiltration membrane.
The filtration / separation device 30 discharges the filtrate that has passed through the treated water channel 26 to which the treated water from the membrane separation activated sludge treatment device 20 is supplied and the reverse osmosis membrane or the nanofiltration membrane of the filtration device 31 and discharges the filtrate. The channel 32 is connected to a concentrated water channel 33 that discharges concentrated water that does not pass through the reverse osmosis membrane or the nanofiltration membrane.

(Filtration and separation device 30)
The filtration separation device 30 includes a filtration device 31 including a reverse osmosis membrane or a nanofiltration membrane.
Filtration device 31 comprises one or more reverse osmosis membrane modules or nanofiltration membrane modules.
The reverse osmosis membrane or the nanofiltration membrane is not particularly limited, and examples thereof include a flat membrane, a tubular membrane, a hollow fiber membrane, and a spiral membrane.
Examples of the material for the reverse osmosis membrane or the nanofiltration membrane include polyamide, polysulfone, and cellulose acetate.
The reverse osmosis membrane module or the nanofiltration membrane module is not particularly limited as long as the filtrate that has passed through the reverse osmosis membrane or the nanofiltration membrane can be separated from the concentrated water that does not pass through the reverse osmosis membrane or the nanofiltration membrane. However, for example, there is a so-called spiral type reverse osmosis membrane module in which a cylindrical reverse osmosis membrane element in which a reverse osmosis membrane is wound around a water collection tube is housed in a cylindrical casing.

  In the method for treating waste liquid using the treatment system 2 shown in FIG. 2, in addition to the evaporative separation step and the membrane separation activated sludge treatment step described above, the treated water from the membrane separation activated sludge treatment apparatus 20 is supplied to the filtration separation apparatus 30. The treatment method is the same as that of the first embodiment except that a filtration separation step of supplying and filtering with a reverse osmosis membrane or a nanofiltration membrane of the filtration device 31 is included.

(Filtration and separation process)
In the filtration and separation step, the treated water from the membrane separation activated sludge treatment device 20 is supplied to the filtration and separation device 30 and passes through the reverse osmosis membrane or the nanofiltration membrane of the filtration device 31, and the reverse osmosis membrane or the nanofiltration. It is separated into concentrated water that does not permeate the membrane.
The filtrate is discharged through the filtrate flow path 32. This filtrate is reused as industrial water (for example, cooling water for various boilers, process water such as a solvent for cleaning liquid) or is directly discharged to the outside, but the environmental load can be reduced and water resources can be effectively used. It is preferably reused from the point. It is possible to provide a treatment method and a treatment system in which waste water is not discharged to the outside (ZLD: zero liquid discharge) by reusing the filtrate. When the filtrate is discharged to the outside, the filtrate may be subjected to a treatment such as ozone treatment or ultraviolet irradiation, if necessary.
On the other hand, the concentrated water is discharged through the concentrated water channel 33 and stored in a concentrated water storage tank (not shown). This concentrated water may be treated as industrial waste.

In the treatment method of the present embodiment, in addition to the same effects as those of the treatment method of the first embodiment, before the filtration separation step, the evaporation separation step and the membrane separation activated sludge treatment step are carried out, organic matter A filtration separation step is performed on the treated water having a reduced concentration. Therefore, due to clogging of the reverse osmosis membrane or the nanofiltration membrane that occurs when the wastewater containing organic matter is directly treated with the reverse osmosis membrane filtration device or the nanofiltration membrane filtration device, the dissolution of the reverse osmosis membrane or the nanofiltration membrane, etc. Damage can be suppressed. According to the treatment method of the present embodiment, the organic matter contained in the organic matter wastewater dissolves the reverse osmosis membrane or the nanofiltration membrane of N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N, N-dimethylformamide or the like. Even if it is a solvent that is easy to do, before the filtration separation step, the evaporation separation step and the membrane separation activated sludge treatment step are performed, and since the filtration separation step is performed on the treated water in which the concentration of these solvents is reduced, It becomes easy to suppress damage due to dissolution of the reverse osmosis membrane or the nanofiltration membrane.
Furthermore, the filtrate obtained from the filtration separation step has a higher water quality than the treated water obtained from the membrane separation activated sludge treatment step and is easy to reuse. Therefore, according to the treatment method and treatment system of the present embodiment, it is easy to construct a treatment method and treatment system in which wastewater is not discharged to the outside (ZLD: zero liquid discharge).
The second embodiment of the present invention can be suitably used particularly for treating wastewater containing high-concentration organic matter.

<Third embodiment>
Next, a method for treating wastewater containing organic matter according to the third embodiment of the present invention will be described.
FIG. 3 is a schematic configuration diagram of the processing system 3 used in the processing method of the present embodiment. The treatment system 3 has the same configuration as the treatment system 2 described in the second embodiment, except that the treatment system 3 includes a concentrated water return passage 34, one end of which is connected to the concentrated water passage 33 and the other end of which is connected to the raw water tank 41. is there.

  In the method for treating wastewater containing organic matter using the treatment system 3, a part of the concentrated water discharged from the filtration separation device 30 is returned to the raw water tank 41 via the concentrated water flow passage 33 and the concentrated water return passage 34. it can.

In the treatment method of the present embodiment, in addition to the same operational effects as the treatment method of the second embodiment, by returning the concentrated water discharged in the filtration separation step to the raw water tank, The evaporation separation step, the separation membrane activated sludge treatment step and the filtration separation step can be performed again. This gives a reusable filtrate from the concentrated water. Therefore, the amount of concentrated water treated as industrial waste can be reduced, and a treatment system with a reduced environmental load can be constructed. Furthermore, the amount of filtrate that can be reused can be increased, and a treatment system that can make more effective use of water resources can be constructed.
The third embodiment of the present invention can be suitably used particularly for treating wastewater containing high-concentration organic matter.

<Other Embodiments>
The present invention has been described by showing the first to third embodiments, but the present invention is not limited to these embodiments.
For example, in the first to third embodiments, an immersion type (integrated type) membrane separation activated sludge treatment device 20 in which a separation membrane is immersed in an activated sludge treatment tank is used as the membrane separation activated sludge treatment device in the MBR process. Used, but not limited to. A so-called external type (separate type) membrane separation activity in which an active treatment tank and a membrane separation tank in which a separation membrane is immersed are each provided, and membrane separation is performed in the membrane separation tank after biological treatment in the active treatment tank. A sludge treatment device may be used.

In the first embodiment, the activated sludge treatment device 20 is arranged downstream of the evaporative separation device 10, but it is not limited to this. For example, a receiving tank for temporarily storing the solution B from the evaporative separation device 10 may be provided between the evaporative separation device 10 and the activated sludge treatment device 20. Further, a receiving tank for temporarily storing the treated water from the activated sludge treatment device 20 may be provided downstream of the activated sludge treatment device 20. By providing the receiving tank, the flow rates of the solution B and the treated water can be easily adjusted.
In 2nd embodiment and 3rd embodiment, although the filtration separation apparatus 30 was arrange | positioned downstream of the activated sludge treatment apparatus 20, it is not limited to this. For example, a receiving tank for temporarily storing the treated water from the activated sludge treatment device 20 may be provided between the activated sludge treatment device 20 and the filtration separation device 30. Further, a receiving tank that temporarily stores the filtrate from the filtration separation device 30 may be provided downstream of the filtration separation device 30.

In the first to third embodiments, the solution A storage tank (not shown), the excess sludge storage tank (not shown), and the concentrated water storage tank (not shown) are provided separately, respectively. Not limited. For example, the solution A storage tank and the excess sludge storage tank are made into one storage tank, and the solution A flow path 13 and the excess sludge flow path 28 are connected to this storage tank, or the solution A storage tank and the excess sludge storage tank are connected. Alternatively, the concentrated water storage tank may be a single storage tank, and the solution A flow path 13, the excess sludge flow path 28, and the concentrated water flow path 33 may be connected to this storage tank.
Furthermore, the membrane separation activated sludge treatment device 20 in the first to third embodiments is provided with a cleaning device for cleaning the separation membrane module 25, and a pump or the like is provided in a flow path connecting each device. Is also optional.

  Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

In this example, wastewater containing high-concentration organic matter was treated by the treatment method shown in the third embodiment using the treatment system 3 shown in the third embodiment.
As the wastewater containing high-concentration organic matter in this example, process wastewater containing a high concentration of N, N-dimethylacetamide (DMAC) was used.

The process wastewater was transferred to the raw water tank 41. The discharge amount of the process waste water was 10.0 m ³ / d. The total organic carbon concentration (TOC) in the process wastewater was 4100 mg / L, and the DMAC concentration in the process wastewater was 0.82% by mass.
Further, the concentrated water separated in the following filtration separation step was returned to the raw water tank 41.

(Evaporative separation process)
The mixed wastewater of the process wastewater and the concentrated water was supplied to the evaporative separation device 10 and separated into a solution B and a solution A under the following conditions.
Discharge of solution B: 8.5 m ³ / d. DMAC concentration in solution B 0.4% by mass, TOC 1700 mg / L.
Discharge amount of solution A: 2.0 m ³ / d. DMAC concentration in solution A 2.4% by mass, TOC 13000 mg / L.

(Membrane separation activated sludge treatment process)
The solution B was supplied to the membrane separation activated sludge treatment device 20 to obtain treated water under the following conditions.
Emission amount of treated water (permeated water): 8.5 m ³ / d. DMAC concentration in treated water 0.004% by mass, TOC 35 mg / L.
Membrane area of separation membrane module: 18 m ² (hollow fiber membrane module of membrane area 6 m ² x 3 units).
Membrane type of separation membrane module: hollow fiber MF membrane containing polyvinylidene fluoride as a main component and having a nominal pore diameter of 0.4 μm.

(Filtration and separation process)
The treated water was supplied to a filtration device 31 equipped with a reverse osmosis membrane, and separated into a filtrate and concentrated water under the following conditions.
Discharge of filtrate: 8.0 m ³ / d. DMAC concentration in the filtrate was 0.0002% by mass, TOC was 1.1 mg / L.
Discharge of concentrated water: 0.5 m ³ / d. DMAC concentration in concentrated water 0.06 mass%, TOC 550 mg / L.
Membrane area of reverse osmosis filtration membrane: 47 m ² (RO membrane module of membrane area 7.9 m ² x 6 units).
Reverse osmosis filtration membrane: Low-pressure spiral type reverse osmosis membrane element (“ESPA2-4040” manufactured by Nitto Denko Corporation).
The filtrate was reused as a cleaning liquid in the manufacturing process. The concentrated water was returned to the raw water tank 41.

  As described above, by applying the present invention, it is possible to construct a treatment method and a treatment system having an excellent balance between the discharge amount of process wastewater discharged from the manufacturing process and the treated amount thereof. Further, it was not necessary to form a large activated sludge tank in the MBR process, and the treatment system could be constructed compactly. Further, the evaporative separation step and the membrane separation activated sludge treatment step are performed before the filtration separation step, and thus the filtration separation step is performed on the treated water having a reduced DMAC concentration, so that the reverse osmosis of the filtration device 31 is performed. No membrane clogging or damage due to dissolution of the reverse osmosis membrane occurred. Furthermore, the filtrate obtained from the filtration and separation step has excellent water quality and can be reused as process water (for example, cleaning liquid) in the manufacturing process. As a result, it was possible to construct a treatment method and a treatment system in which wastewater was not discharged outside (ZLD: zero liquid discharge).

1-3 Treatment system 10 Evaporative separator 11 Evaporative separator 20 Membrane separation activated sludge treatment device 21 Activated sludge tank 22 Air diffuser 25 Separation membrane module 30 Filtration separation device 31 Filtration device

Claims (14)

Wastewater containing organic matter,
An evaporative separation step of performing an evaporative concentration treatment or a distillation treatment to separate the solution A in which the organic matter is concentrated and the solution B in which the concentration of the organic matter is reduced;
Said solution B, seen including a membrane separation activated sludge treatment process to obtain a treated water treated by the membrane separation activated sludge treatment method,
Organic substances contained in the waste water containing the organic substance, is N, N- dimethylacetamide, N- methyl-2-pyrrolidone and N, wherein including Mukoto one or more compounds selected from N- dimethylformamide, organic Wastewater treatment method including. Waste water containing organic matter having a boiling point of 100 ° C. or higher under normal pressure,
An evaporative separation step of performing evaporative concentration treatment to separate the solution A in which the organic matter is concentrated and the solution B in which the concentration of the organic matter is reduced;
Said solution B, seen including a membrane separation activated sludge treatment process to obtain a treated water treated by the membrane separation activated sludge treatment method,
Organic substances contained in the waste water containing the organic substance, is N, N- dimethylacetamide, N- methyl-2-pyrrolidone and N, wherein including Mukoto one or more compounds selected from N- dimethylformamide, organic Wastewater treatment method including. Wastewater containing organic matter having a boiling point under atmospheric pressure of less than 100 ° C.,
An evaporation separation step of performing a distillation process to separate the solution A in which the organic matter is concentrated and the solution B in which the concentration of the organic matter is reduced;
Said solution B, seen including a membrane separation activated sludge treatment process to obtain a treated water treated by the membrane separation activated sludge treatment method,
Organic substances contained in the waste water containing the organic substance, is N, N- dimethylacetamide, N- methyl-2-pyrrolidone and N, wherein including Mukoto one or more compounds selected from N- dimethylformamide, organic Wastewater treatment method including.   The method for treating wastewater containing organic matter according to claim 1, wherein the treated water is reused.   Further, the treated water is filtered by a reverse osmosis membrane or a nanofiltration membrane, and separated into a filtrate that has passed through the reverse osmosis membrane or the nanofiltration membrane and concentrated water that does not pass through the reverse osmosis membrane or the nanofiltration membrane. The method for treating wastewater containing organic matter according to any one of claims 1 to 3, comprising a filtration separation step.   The method for treating wastewater containing organic matter according to claim 5, wherein the filtrate is reused.   Furthermore, the concentrated water is returned to the said evaporation separation process, The processing method of the waste water containing the organic substance of Claim 5 or Claim 6 characterized by the above-mentioned.   The total organic carbon (TOC) concentration of the wastewater containing organic matter is 2,000 to 50,000 mg / L, and the wastewater containing organic matter according to any one of claims 1 to 7. Processing method. An evaporative separation device that evaporatively concentrates or distills wastewater containing organic matter to separate it into a solution A in which the organic matter is concentrated and a solution B in which the concentration of the organic matter is reduced,
A membrane separation activated sludge treatment device for treating the solution B by a membrane separation activated sludge treatment method to obtain treated water ,
The organic matter contained in the wastewater containing the organic matter contains one or more compounds selected from N, N-dimethylacetamide, N-methyl-2-pyrrolidone and N, N-dimethylformamide , Wastewater treatment system including. The treatment system for wastewater containing organic matter according to claim 9 , further comprising a treated water channel for reusing the treated water. Further, the treated water is filtered by a reverse osmosis membrane or a nanofiltration membrane, and separated into a filtrate that has passed through the reverse osmosis membrane or the nanofiltration membrane and concentrated water that does not pass through the reverse osmosis membrane or the nanofiltration membrane. The wastewater treatment system containing organic matter according to claim 9 , further comprising a filtration separation device. The treatment system for wastewater containing organic matter according to claim 11 , further comprising a filtrate flow path for reusing the filtrate. The treatment system for wastewater containing organic matter according to claim 11 or 12 , further comprising a concentrated water return path for returning the concentrated water to the evaporation / separation device. The total organic carbon (TOC) concentration of the wastewater containing the organic matter is 2,000 to 50,000 mg / L, and the wastewater containing the organic matter according to any one of claims 9 to 13 . Processing system.

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