KR20060052370A - Apparatus and process for recovering water from organic containing water - Google Patents

Abstract

The present invention provides a device for recovering water from organic matter-containing water and a method for recovering water, which can reduce the cumbersome pH adjustment process and further suppress the blocking of the RO membrane and the decrease in flow rate over a long period of time.

Organic treatment of organic matter-containing water, and after adjusting the pH of the filtered water obtained by filtration of the biological treatment water with alkali, the organic matter-containing water characterized in that the permeate obtained through the reverse osmosis membrane device is recovered as treated water. And method for recovering water from water.

Description

Apparatus and Process for Recovering Water from Organic Containing Water

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recovering water from organic-containing water using a reverse osmosis (hereinafter simply referred to as RO) membrane apparatus, and a method for recovering water. Particularly, electronic component members (for example, semiconductor devices such as semiconductors using wafers) The present invention relates to a recovery apparatus and a recovery method suitable for recovery reuse of electronic component member manufacturing process water from the manufacturing process drainage.

Conventionally, as a method for recovering pure water from the wastewater from electronic component manufacturing process, for example, the semiconductor washing wastewater is adjusted to pH 6-9, and then subjected to biotreatment and evaporation, and then adjusted to pH 4-7. After the ion or biological treatment including NH ₄ ⁺ in the feed water using a first RO membrane separation device, most of the remaining organic matter is removed and permeated, the permeate is adjusted to pH 7-9, and the second RO membrane is separated. A method of efficiently removing CO ₂ as a HCO ₃ ⁻ by the desalting function of an RO membrane by permeation, and recovering pure water has been proposed (for example, JP-A-6-328070).

However, in the above-mentioned recovery method, the number of steps is large, and there are many operations for complicated pH adjustment. Moreover, when the to-be-processed water after biological treatment is supplied to the RO membrane separation apparatus, there existed a problem that the blocking of RO membrane and the fall of permeate flow rate generate | occur | produce.

[Document 1] Japanese Unexamined Patent Publication No. 6-328070

SUMMARY OF THE INVENTION An object of the present invention is to reduce the number of steps, in particular, a complicated pH adjustment step, and further to suppress the blockage of the RO membrane and the decrease in the flow rate over a long period of time, thereby providing an apparatus and a method for recovering water from organic-containing water having excellent durability. To provide.

The present inventors have found that the main cause is that the blockage of the RO membrane and the decrease in flow rate are caused by organic substances such as metabolites of the cells in the biological treatment included in the biological treatment water to adhere to the membrane surface. In addition, in order to suppress adhesion of organic substances to such a membrane surface, it has been found that the pH of the feed water (filtration water) to the RO membrane apparatus can be effectively solved by adjusting the pH to 9 or more, preferably 10 or more.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, in the collection method of the water from the organic substance containing water which concerns on this invention, after adjusting the pH of the filtrate obtained by filtering an organic substance containing water, and filtering the said biologically treated water with alkali, a reverse osmosis membrane And permeate water obtained by passing through the device is recovered as treated water. In such a recovery method, the number of steps, in particular, a complicated pH adjustment step can be reduced, and the blockage of the RO membrane and the decrease in flow rate can be suppressed over a long period of time.

The method of biological treatment is not particularly limited, and known biological treatment methods can be applied.

In addition, the filtration method of the said biologically treated water is not specifically limited, For example, the thing provided with the backwashing mechanism which used sand and activated carbon for a filter medium can be used.

PH of the said filtrate can be adjusted by adding alkali, such as caustic soda continuously or intermittently, for example. In the case of adjusting the pH intermittently, when the alkali addition time is set to 10 minutes or more, preferably 1 hour or more, the performance of the RO membrane device can be more stabilized.

It is preferable to use a reverse osmosis composite membrane for the RO membrane, and in particular, by using a highly fouling reverse osmosis composite membrane, the effect of the present invention can be more markedly expressed.

The method for recovering water from organic matter-containing water according to the present invention can be applied to the recovery of treated water from organic matter-containing water such as drainage in a wide range of industrial fields. It is preferable to use it for collection | recovery of the high purity electronic component parts manufacturing process water which can be used for washing | cleaning electronic component parts from waste water. In addition, the method for recovering water from the organic-containing water according to the present invention can be widely applied from the low concentration to the high concentration of the entire organic matter in the organic-containing water. For example, the total organic carbon contained in the organic-containing water is It is also applicable to drainage highly contaminated above 10 mg / L.

In order to solve the said subject, the collection | recovery apparatus of the water from the organic substance containing water which concerns on this invention is the biological treatment means for bioprocessing organic substance containing water, the filtration means for filtering biologically treated water, pH adjustment which adjusts pH of filtered water to alkali. Means and a reverse osmosis membrane means for transmitting permeate water through the filtrate adjusted with alkali. In such a recovery apparatus, compared with the conventional recovery apparatus, the number of steps, in particular, the number of complicated pH adjustment steps can be reduced. It is also applicable to the case where water is to be recovered from extremely contaminated organic matter-containing water. In addition, since the water supplied to the RO membrane separation means is appropriately treated, blockage of the RO membrane and a decrease in the permeation flow rate can be suppressed, and the durability of the RO membrane and the entire recovery device can be improved.

The said biological treatment means is not specifically limited, A well-known biological treatment means can be applied.

In addition, the filtration means of the said biologically treated water is not specifically limited, For example, the thing provided with the backwashing mechanism which used sand and activated carbon for a filter medium can be used.

As described above, the main cause is that the blockage of the RO membrane and the decrease in the flow rate are caused by organic substances such as metabolites of the cells at the time of biological treatment included in the biological treatment water to adhere to the membrane surface. It is more effective to adjust pH of the feed water (filtration water) to RO membrane apparatus to 9 or more, Preferably it is 10 or more in order to suppress adhesion of the organic substance to such a membrane surface. Therefore, it is preferable that the collection | recovery apparatus of the water from organic substance containing water has a means which adjusts pH to 9 or more by adding alkali to filtered water. The addition of alkali may be continuous or intermittent. In the means for adjusting the pH to 9 or more by adding alkali intermittently, setting the time of one alkali addition to 10 minutes or more, preferably 1 hour or more can further stabilize the performance of the RO membrane device.

It is preferable to use a reverse osmosis composite membrane for the RO membrane of the reverse osmosis membrane means, and the effect of the present invention can be more markedly expressed by using a highly fouling reverse osmosis composite membrane.

The apparatus for recovering water from organic matter-containing water according to the present invention can be applied to the recovery of treated water from organic matter-containing water, such as drainage, in a wide range of industrial fields. It is preferable as a recovery apparatus of the high purity electronic component parts manufacturing process water which can be used for washing | cleaning electronic component parts from waste water. Moreover, the water collection | recovery apparatus from the organic substance containing water which concerns on this invention can be applied widely from low density | concentration to the high density | concentration of all organic substance in organic substance containing water, For example, the total organic carbon contained in organic substance containing water is It is also applicable to drainage highly contaminated above 10 mg / L.

According to the present invention, the number of steps, in particular, the complicated pH adjustment step can be reduced, and further, the blockage of the RO membrane and the decrease in the flow rate can be suppressed over a long period of time, thereby greatly improving the operating efficiency of the apparatus.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Below, preferred embodiment of this invention is described with reference to drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The whole water circulation system in the semiconductor manufacturing equipment in which the water collection | recovery apparatus from the organic substance containing water which concerns on one Embodiment of this invention was assembled is shown. In FIG. 1, 1 represents a pretreatment system for pretreatment of river water, groundwater and industrial water, 2 is a primary pure water system, and 3 is a secondary pure water system. The ultrapure water produced in the secondary pure water system 3 via the primary pure water system 2 is supplied to each use point 4 in the semiconductor manufacturing facility, and is used, for example, for cleaning the semiconductor. The ultrapure water used in semiconductor manufacturing becomes drainage (organic-containing water) containing impurities such as organic chemicals used in the manufacture of semiconductors, and is sent to the recovery device 6 of water from the organic-containing water through the drain pipe 5. Lose. The permeated water from which impurities such as organic substances have been removed by the recovery device 6 is again supplied to the primary pure water system 2 through the supply pipe 16. Thus, the water circulation system in a semiconductor manufacturing facility is comprised.

The recovery apparatus 6 of water from organic substance containing water is comprised as shown in FIG. Drainage from the drain pipe 5 is stored in the drain water tank 7. The other waste water stored in the drain water tank 7 is biotreated in the biological treatment means 8 and then supplied to the filtering means 10 (sand filtration tower) through the first intermediate tank 9. The filtrate filtered by the filtering means 10 passes through the second intermediate tank 11, the activated carbon tower 12, and is also pH adjusted by the pH adjusting means 13, and then the RO through the safety filter 14 Supplied to the membrane means 15.

In addition, the pH adjustment means 13 is comprised from the means which can add alkali continuously or intermittently.

<Example>

Although an Example is given to the following and this invention is demonstrated to it further more concretely, this is only an illustration and does not limit this invention.

<Example 1>

By the apparatus shown in FIG. 2, the electronic component parts manufacturing process waste water (organic-containing water) of the water quality shown in following Table 1 was processed as raw water. At this time, the supply water to the RO membrane means 15 was adjusted to pH 9 by NaOH. The time-dependent change of the process flow velocity of RO film | membrane in RO membrane means 15 is shown in FIG.

<Example 2>

By the apparatus shown in FIG. 2, the raw-material electronic component parts manufacturing process wastewater (organic-containing water) shown in Table 1 was processed. At this time, the supply water to the RO membrane means 15 was adjusted to pH 10 by NaOH. The change with time of the process flow rate of the RO film in the RO film means 15 is shown in FIG.

<Example 3>

By the apparatus shown in FIG. 2, the raw-material electronic component parts manufacturing process wastewater (organic-containing water) shown in Table 1 was processed. At this time, the supply water to the RO membrane means 15 was adjusted to pH 11 by NaOH. The change with time of the process flow rate of the RO film in the RO film means 15 is shown in FIG.

<Example 4>

By the apparatus shown in FIG. 2, the raw-material electronic component parts manufacturing process wastewater (organic-containing water) shown in Table 1 was processed. At this time, the supply water to the RO membrane means 15 was adjusted to pH 11 by NaOH. In addition, addition of NaOH by pH adjusting means was performed continuously for 1 hour, and the cycle which does not perform addition for 11 hours after that was repeated. The change with time of the process flow rate of the RO film in the RO film means 15 is shown in FIG. The data of Example 3, in which NaOH was added continuously for comparison, is shown in FIG. 4.

Comparative Example 1

By the apparatus shown in FIG. 2, the raw-material electronic component parts manufacturing process wastewater (organic-containing water) shown in Table 1 was processed. At this time, pH adjustment was not carried out to the water supplied to the RO membrane means 15. The change with time of the process flow rate of the RO film in the RO film means 15 is shown in FIG.

As is clear from Fig. 3, in Example 1 (pH = 9), Example 2 (pH = 10), and Example 3 (pH = 11), the decrease in the permeation flux over time is very small and stable over a long period of time. It can be seen that water is being recovered. In particular, as in Examples 2 and 3, when the pH is adjusted to 10 or more, the effect is remarkable. On the other hand, in the case of the comparative example 1, the permeation | flow_flow rate declined from the beginning, and the permeation | flow_flow rate after 10 days fell to about 0.4, and has since transitioned to the stable state. Therefore, in the case of the comparative example 1, it is thought that the whole RO film | membrane was almost completely occluded 10 days after the start of operation.

4, the permeation flux of Example 3 in which the pH was adjusted to 11 by adding NaOH continuously and Example 4 in which the pH was adjusted to 11 by intermittently adding NaOH were almost unchanged. It was found that the addition of alkali may be performed continuously or intermittently.

According to the present invention, the number of steps, in particular, the complicated pH adjustment step can be reduced, and further, the blockage of the RO membrane and the decrease in the flow rate can be suppressed over a long period of time, thereby greatly improving the operating efficiency of the apparatus.

Moreover, although the collection | recovery apparatus and collection | recovery method of the water from organic matter containing water which concerns on this invention are widely applicable as a collection | recovery apparatus which collect | recovers water from waste water etc., it is especially suitable for collection | recovery of the pure water from the wastewater manufacturing process of electronic component parts. will be.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the water circulation system in a semiconductor manufacturing facility in which the water collection | recovery apparatus from the organic substance containing water which concerns on one Embodiment of this invention was assembled.

2 is a schematic apparatus flow diagram of an apparatus for recovering water from organic matter-containing water according to an embodiment of the present invention.

It is a characteristic view which shows the measurement result of the permeation flow rate in an Example and a comparative example.

Fig. 4 is a characteristic diagram showing a measurement result of the permeation flux in the case where NaOH is added continuously and in the case of adding intermittently.

<Description of Major Codes in Drawings>

1: pretreatment system 2: primary pure water system

3: 2nd pure system 4: use point

5: drain piping 7: drainage tank

6: recovery apparatus of water from organic matter-containing water 8: biological treatment means

9: first intermediate bath 10: filtration means

11: second half 12: activated carbon tower

13: pH adjusting means 14: safety filter

15: RO membrane means 16: supply piping

Claims (14)

After biologically treating the organic matter-containing water, the pH of the filtered water obtained by filtering the biologically treated water is adjusted to alkali, and then the permeated water obtained by passing through the reverse osmosis membrane device is recovered as treated water. Recovery of water. The method for recovering water from organic matter-containing water according to claim 1, wherein the filtration is either sand filtration and / or activated carbon filtration. The method for recovering water from organic-containing water according to claim 1 or 2, wherein an alkali is continuously added to the filtrate and the pH of the filtrate is adjusted to 9 or more. The method for recovering water from organic-containing water according to claim 1 or 2, wherein an alkali is added to the filtrate intermittently and the pH of the filtrate is adjusted to 9 or more. The method for recovering water from organic matter-containing water according to claim 1, wherein drainage is used for the organic matter-containing water. The method for recovering water from organic-containing water according to claim 5, wherein the wastewater is a wastewater of an electronic component part manufacturing process. The method for recovering water from organic-containing water according to claim 1, wherein the total organic carbon contained in the organic-containing water is 10 mg / L or more. Biological treatment means for biologically treating organic matter-containing water, filtration means for filtering biologically treated water, pH adjusting means for adjusting pH of the filtered water to alkali, and reverse osmosis membrane means for permeating the filtered water adjusted with alkali to obtain permeate. An apparatus for recovering water from organic matter-containing water, which has: 9. The apparatus of claim 8, wherein the filtration means comprises any one of sand filtration means and / or activated carbon filtration means. 10. The apparatus for recovering water from organic-containing water according to claim 8 or 9, wherein said pH adjusting means comprises means for continuously adding alkali to the filtered water to adjust the pH to 9 or more. 10. The apparatus for recovering water from organic-containing water according to claim 8 or 9, wherein said pH adjusting means includes means for adjusting the pH to 9 or more by adding alkali to the filtered water intermittently. The apparatus for recovering water from organic substance-containing water according to claim 8, wherein the organic substance-containing water comprises waste water. 13. The apparatus for recovering water from organic-containing water according to claim 12, wherein the wastewater comprises wastewater in an electronic component part manufacturing process. The water-recovering apparatus of the organic substance containing water of Claim 8 whose total organic carbon contained in the said organic substance containing water is 10 mg / L or more.