JP2009274006A - Wastewater treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wastewater treatment apparatus which lowers a concentration of IPA of a water to be treated such as a cleaning wastewater to a lower concentration by using a reverse osmosis membrane apparatus and also reduces a volume of the wastewater. <P>SOLUTION: The waste water treatment apparatus includes a tank 1 for the water to be treated for storing the water to be treated, a first reverse osmosis membrane apparatus 10a which treats the water to be treated supplied from the tank 1 for the water to be treated and discharges it as a first step permeated water in which an impurity in the water to be treated is removed and the first step concentrated water in which the impurity is concentrated, a second reverse osmosis membrane apparatus 10b which receives the first step concentrated water and discharges it as a second-step permeated water in which the impurity in the first step concentrated water is removed and a second step concentrated water in which the impurity is concentrated, and a permeated-water recovering line 3 which recovers the second step permeated water into the tank 1 for the water to be treated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a wastewater treatment apparatus, and more particularly to a wastewater treatment apparatus that treats cleaning wastewater containing isopropyl alcohol (hereinafter referred to as IPA) using a reverse osmosis membrane device.

  In recent years, IPA is widely used in a drying process in a wet cleaning process in semiconductor manufacturing, and the used IPA is discharged as cleaning waste water together with rinse waste water of the semiconductor wafer and moisture removed from the semiconductor wafer. With respect to the washing wastewater containing IPA, IPA is recovered by a distillation method. However, since this method requires heating energy, the cost increases as the amount of washing wastewater increases. For this reason, it has been studied to treat washing wastewater containing IPA in a wastewater treatment apparatus using a reverse osmosis membrane device before distillation.

  The reverse osmosis membrane device selectively permeates and collects only water as a solvent by applying a pressure higher than the osmotic pressure of the water to be treated, utilizing the property of the reverse osmosis membrane that allows the solvent to pass but does not allow the solute to permeate. Device. Using this reverse osmosis membrane device, there is a pure water production apparatus equipped with a membrane-type deaeration unit that removes impurities and the like in treated water and degassed dissolved gas downstream of the reverse osmosis membrane unit ( For example, see Patent Document 1).

JP 2004-160379 A

  However, in the pure water production apparatus as described in Patent Document 1, it is difficult to obtain pure water reduced to a low concentration of IPA, and IPA discharged from the reverse osmosis membrane portion is concentrated. In addition, there is a problem that the amount of the concentrated water is large and the cost is high when distilling.

  Therefore, it is required to use a reverse osmosis membrane device to reduce IPA to be treated such as washing wastewater to a low concentration and to reduce the volume of wastewater (volume reduction). The above is the subject of the present invention.

This invention is made | formed in view of such a subject, and makes it the 1st objective to reduce the volume (volume reduction) of concentrated wastewater using a reverse osmosis membrane apparatus.
A second object is to reduce impurities such as IPA of water to be treated to a low concentration using a reverse osmosis membrane device.

  The present inventor has found that by performing a multi-stage treatment with a reverse osmosis membrane device, volume reduction and impurities in water to be treated can be reduced to a low concentration, and based on this, the following new waste water is obtained. It came to invent a processing apparatus.

  (1) A treated water tank for storing treated water and treated water supplied from the treated water tank, and the first-stage permeated water and impurities removed from the treated water are concentrated. The first reverse osmosis membrane device that discharges as the first-stage concentrated water, the second-stage permeated water from which the first-stage concentrated water is supplied, and the impurities in the first-stage concentrated water are removed, and the impurities are concentrated. A second reverse osmosis membrane device that discharges as the second-stage concentrated water, and a permeate recovery line that recovers the second-stage permeate to the treated water tank. A wastewater treatment apparatus characterized by being collected.

  (2) A treated water tank for storing treated water and treated water supplied from the treated water tank, and the first-stage permeated water and impurities removed from the treated water are concentrated. The first reverse osmosis membrane device that discharges as the first-stage concentrated water, the second-stage permeated water from which the first-stage concentrated water is supplied, and the impurities in the first-stage concentrated water are removed, and the impurities are concentrated. The second reverse osmosis membrane device that discharges as the second-stage concentrated water, and the third-stage permeated water from which the first-stage permeated water is supplied and impurities in the first-stage permeated water are removed and the impurities are concentrated. A third reverse osmosis membrane device that discharges as the third-stage concentrated water, a permeate recovery line that recovers the second-stage permeate to the treated water tank, and the third-stage concentrated water to be treated A concentrated water recovery line for recovery in a water tank, and the third stage permeation Waste water treatment apparatus is characterized in that so as to collect.

  (3) A concentrated water tank for storing concentrated water is provided in the concentrated water supply line between the first reverse osmosis membrane device and the second reverse osmosis membrane device (1) or (2) The waste water treatment apparatus as described.

  (4) The permeated water tank for storing permeated water is provided in the permeated water supply line between the first reverse osmosis membrane device and the third reverse osmosis membrane device (2). Wastewater treatment equipment.

According to the present invention (1), the volume of concentrated waste water can be reduced (volume reduction) using a reverse osmosis membrane device.
According to the present invention (2), the reverse osmosis membrane device can be used to reduce impurities such as IPA to be treated to a low concentration.

  Hereinafter, embodiments of the present invention will be described. The wastewater treatment apparatus according to the first embodiment includes a first reverse osmosis membrane device that treats water to be treated supplied from a water tank to be treated that stores the water to be treated. The treated water is treated by the first reverse osmosis membrane device, and the first-stage permeated water from which impurities in the treated water are removed and the first-stage concentrated water from which impurities are concentrated are discharged. The discharged first-stage concentrated water is supplied to the second reverse osmosis membrane device, processed in the second reverse osmosis membrane device, and the second-stage permeated water from which impurities in the first-stage concentrated water are removed and impurities are removed. Drain as concentrated second stage concentrated water. Then, the second-stage permeated water is collected in the water tank to be treated through the permeated water collection line, and the first-stage permeated water is collected.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a system configuration diagram of a wastewater treatment apparatus according to a first embodiment of the present invention.

  As shown in FIG. 1, the wastewater treatment apparatus of the first embodiment includes a treated water tank 1 that stores treated water and a first reverse that treats treated water supplied from the treated water tank 1. The osmosis membrane device 10a, the concentrated water tank 2 for storing the first-stage concentrated water discharged from the first reverse osmosis membrane device 10a, and the second reverse for processing the concentrated water supplied from the concentrated water tank 2 The osmosis membrane device 10b and the permeable water recovery line 3 for recovering the second-stage permeable water discharged from the second reverse osmosis membrane device 10b to the water tank 1 to be treated are provided.

  The reverse osmosis membrane devices 10a and 10b use a reverse osmosis membrane (RO) having a property of allowing a solvent to pass but not allowing a solute to pass through, so that water to be treated containing impurities such as isopropyl alcohol (hereinafter referred to as IPA) is used. By applying a pressure higher than the osmotic pressure, only water as a solvent is selectively permeated and collected. As shown in FIG. 1, a reverse osmosis membrane device 10a, 10b is a cylindrical reverse osmosis membrane module (hereinafter referred to as RO module) 11 provided with a number of reverse osmosis membranes or nanofiltration membranes (both not shown). A treated water line 12 provided upstream of the RO module 11, a pump 13 provided in the treated water line 12 for pressurizing treated water, and a downstream side of the RO module 11. An RO treatment water line (permeate water line) 14 that supplies treated water from which impurities are removed, and a concentrated water line that is provided downstream of the RO module 11 and drains concentrated water enriched with impurities. 15.

  The treated water tank 1 stores treated water such as cleaning wastewater containing IPA used for wet cleaning or the like in the semiconductor manufacturing process. The treated water in the treated water tank is supplied from the treated water line 12 to the RO module 11 by the pump 13 of the first reverse osmosis membrane device 10a, and the permeated water treated in the RO module 11 is the permeated water line. 14 is collected as treated water.

  The concentrated water that has been processed in the RO module 11 of the first reverse osmosis membrane device 10 a and concentrated in impurities is discharged as concentrated water from the concentrated water line 15 and stored in the concentrated water tank 2. The concentrated water stored in the concentrated water tank 2 is supplied from the treated water line 12 to the RO module 11 of the second reverse osmosis membrane device 10b by the pump 13 of the second reverse osmosis membrane device 10b. The second-stage permeated water treated in step 2 is recovered from the permeated water line 14 to the treated water tank 1 via the permeated water recovery line 3 and processed in the RO module 11 of the second reverse osmosis membrane device 10b. The two-stage concentrated water is discharged from the concentrated water line 15. The discharged second stage concentrated water is subjected to reprocessing such as distillation or discarded.

  In the wastewater treatment apparatus of the first embodiment, the first stage concentrated water of the first reverse osmosis membrane device 10a is treated in the second reverse osmosis membrane device 10b, and then the permeated water of the second reverse osmosis membrane device 10b. Is recovered in the water tank 1 to be treated, so that the first-stage concentrated water discharged from the first reverse osmosis membrane device 10a is reprocessed by the second reverse osmosis membrane device 10b without being discarded, and most of it is permeated. It is recovered in the water tank 1 to be treated via the water recovery line 3 and the rest is discharged as the second stage concentrated water. Therefore, the volume of the second stage concentrated water is greatly reduced as compared with the first stage concentrated water, and the volume reduction of the concentrated water can be achieved.

  FIG. 2 is a system configuration diagram of the wastewater treatment apparatus according to the second embodiment of the present invention.

  As shown in FIG. 2, the wastewater treatment apparatus of the second embodiment includes a treated water tank 1 that stores treated water and a first reverse that treats treated water supplied from the treated water tank 1. The osmosis membrane device 10a, the concentrated water tank 2 for storing the first-stage concentrated water discharged from the first reverse osmosis membrane device 10a, and the second reverse for processing the concentrated water supplied from the concentrated water tank 2 The osmosis membrane device 10b, the permeate recovery line 3 for recovering the second stage permeate discharged from the second reverse osmosis membrane device 10b to the treated water tank 1, and the permeate of the first reverse osmosis membrane device 10a A permeated water tank 4 for storing the first-stage permeated water discharged from the line 14, a third reverse osmosis membrane device 10c for treating the permeated water supplied from the permeated water tank 4, and a third reverse osmosis membrane device. The second stage concentrated water discharged from 10c is collected in the treated water tank 1. It is constituted by a Chijimisui recovery line 5.

  The treated water tank 1 stores treated water such as cleaning wastewater containing IPA used for wet cleaning or the like in the semiconductor manufacturing process. The treated water in the treated water tank is supplied from the treated water line 12 to the RO module 11 of the first reverse osmosis membrane device 10 a by the pump 13 of the first reverse osmosis membrane device 10 a and processed in the RO module 11. The permeated water is discharged from the permeated water line 14 to the permeated water tank 4 and discharged to the concentrated water tank 2 processed in the RO module 11. The concentrated water stored in the concentrated water tank 2 is supplied from the treated water line 12 to the RO module 11 of the second reverse osmosis membrane device 10b by the pump 13 of the second reverse osmosis membrane device 10b. The second-stage permeated water treated in step 2 is recovered from the permeated water line 14 to the treated water tank 1 via the permeated water recovery line 3 and processed in the RO module 11 of the second reverse osmosis membrane device 10b. The two-stage concentrated water is discharged from the concentrated water line 15. The discharged second stage concentrated water is subjected to reprocessing such as distillation or discarded.

  The permeated water stored in the permeated water tank 4 is supplied to the RO module 11 of the third reverse osmosis membrane device 10c by the pump 13 of the third reverse osmosis membrane device 10c. The permeated water treated by the RO module 11 of the third reverse osmosis membrane device 10 c is collected from the permeated water line 14, and the second stage concentrated water enriched with impurities is treated water tank via the concentrated water recovery line 5. 1 recovered.

  In the wastewater treatment apparatus of the second embodiment, after the first-stage concentrated water of the first reverse osmosis membrane device 10a is treated in the second reverse osmosis membrane device 10b, the second Since the permeated water of the reverse osmosis membrane device 10b is collected in the water tank 1 to be treated, the first-stage concentrated water discharged from the first reverse osmosis membrane device 10a is not discarded but is discarded by the second reverse osmosis membrane device 10b. Reprocessing is performed, and most of the water is recovered in the water tank 1 to be treated through the permeate recovery line 3, and the rest is discharged as second-stage concentrated water. Therefore, the volume of the second stage concentrated water is greatly reduced as compared with the first stage concentrated water, and the volume reduction of the concentrated water can be achieved.

  Furthermore, in 2nd Embodiment, the 1st stage permeate discharged | emitted from the 1st reverse osmosis membrane apparatus 10a is processed again in the 3rd reverse osmosis membrane apparatus 10c, and is discharged | emitted from the 3rd reverse osmosis membrane apparatus 10c. Since the second-stage permeate is collected, impurities such as IPA are reduced in the second-stage permeate compared to the first-stage permeate. As described above, in the second embodiment, volume reduction can be achieved in the same manner as in the first embodiment, and the collected permeated water has a lower concentration of impurities, and can be reused as washing water. It is.

  Note that the concentrated water tank 2 and the permeated water tank 4 in the first and second embodiments can perform a buffering function when a membrane or the like is generated in the RO module 11 and the discharge amount of the treated water is reduced. However, the concentrated water tank 2 and the permeated water tank 4 in the first and second embodiments can be implemented without them.

  As described above, according to the embodiment of the present invention, after the first-stage concentrated water of the first reverse osmosis membrane device is processed in the second reverse osmosis membrane device, the second reverse osmosis membrane device. Is recovered in the tank to be treated, so that the first-stage concentrated water discharged from the first reverse osmosis membrane device is reprocessed by the second reverse osmosis membrane device without being discarded, and most of the recovered water is recovered in the recovery line. And the rest is discharged as second-stage concentrated water. Therefore, the volume of the second stage concentrated water is greatly reduced as compared with the first stage concentrated water, and the volume reduction of the concentrated water can be achieved. Accordingly, the discharged concentrated water can be distilled with less heating energy than before, and the IPA recovery cost can be reduced.

  In addition, according to the embodiment of the present invention, the first-stage permeated water discharged from the first reverse osmosis membrane device is processed again in the third reverse osmosis membrane device and discharged from the third reverse osmosis membrane device. Since the second-stage permeated water is collected, impurities such as IPA are lower in the second-stage permeated water than in the first-stage permeated water. As described above, in the second embodiment, volume reduction can be achieved in the same manner as in the first embodiment, and the collected permeated water is further reduced in concentration, so that it can be reused as washing water. .

  Further, according to the embodiment of the present invention, the concentrated water tank for storing the concentrated water is provided in the concentrated water line between the first reverse osmosis membrane device and the second reverse osmosis membrane device. It is possible to perform a buffering function when a membrane clogging or the like occurs on the surface and the discharge amount of concentrated water decreases.

  Moreover, according to the embodiment of the present invention, since the permeated water supply line between the first reverse osmosis membrane device and the third reverse osmosis membrane device is provided with the permeated water tank for storing permeated water, RO It is possible to perform a buffer function when a membrane or the like is generated in the module and the discharge amount of permeated water is reduced.

  As mentioned above, although embodiment of this invention was described, it only showed the specific example and does not limit this invention in particular, The 1st reverse osmosis membrane apparatus 10a, the 2nd reverse osmosis membrane apparatus 10b, The specific configurations and arrangements of the reverse osmosis membrane device 10c, the permeated water recovery line 3, the concentrated water recovery line 5, the concentrated water tank 2, the permeated water tank 4 and the like can be appropriately changed. In particular, the number of reverse osmosis membrane devices can be configured in an arbitrary plurality of stages, and the number of arrangements in the above embodiment is merely an example. In addition, the effects described in the above-described embodiment only list the most preferable effects resulting from the present invention, and the effects according to the present invention are not limited to those described in the embodiments of the present invention. Absent.

1 is a system configuration diagram of a wastewater treatment apparatus according to a first embodiment of the present invention. It is a system block diagram of the waste water treatment apparatus of 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Treated water tank 2 Concentrated water tank 4 Permeated water tank 5 Permeated water collection | recovery line 10a 1st reverse osmosis membrane apparatus 10b 2nd reverse osmosis membrane apparatus 10c 3rd reverse osmosis membrane apparatus

Claims (4)

A treated water tank for storing treated water;
1st reverse osmosis which processes the to-be-processed water supplied from the to-be-processed water tank, and discharge | releases as 1st stage permeated water from which the impurities in this to-be-processed water were removed, and 1st stage concentrated water with which the impurities were concentrated A membrane device;
A second reverse osmosis membrane device that is supplied with the first-stage concentrated water and discharges the second-stage permeated water from which impurities in the first-stage concentrated water are removed and the second-stage concentrated water in which impurities are concentrated;
A permeate recovery line for recovering the second stage permeate to the treated water tank,
A wastewater treatment apparatus characterized in that the first-stage permeate is collected. A treated water tank for storing treated water;
1st reverse osmosis which processes the to-be-processed water supplied from the to-be-processed water tank, and discharge | releases as 1st stage permeated water from which the impurities in this to-be-processed water were removed, and 1st stage concentrated water with which the impurities were concentrated A membrane device;
A second reverse osmosis membrane device that is supplied with the first-stage concentrated water and discharges the second-stage permeated water from which impurities in the first-stage concentrated water are removed and the second-stage concentrated water in which impurities are concentrated;
A third reverse osmosis membrane device that is supplied with the first-stage permeated water and discharges the third-stage permeated water from which impurities in the first-stage permeated water are removed and the third-stage concentrated water in which impurities are concentrated;
A permeate recovery line for recovering the second stage permeate to the treated water tank;
A concentrated water recovery line for recovering the third stage concentrated water in the treated water tank,
A wastewater treatment apparatus characterized in that the third-stage permeate is collected.   The concentrated water tank which stores concentrated water in the concentrated water supply line between the said 1st reverse osmosis membrane apparatus and the said 2nd reverse osmosis membrane apparatus was provided. Waste water treatment equipment.   The wastewater treatment according to claim 2, wherein a permeate tank for storing permeate is provided in a permeate water supply line between the first reverse osmosis membrane device and the third reverse osmosis membrane device. apparatus.

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