TWI461372B - Processing method and processing device containing organic matter drainage - Google Patents

Description

Processing method and processing device containing organic matter drainage

In the present invention, when a reverse osmosis (RO) membrane separation apparatus for wastewater containing high to low concentrations of organic matter (TOC) discharged from an electronic equipment manufacturing plant or the like is treated and recovered, the organic membrane is prevented from being adsorbed on the membrane surface by the RO membrane separation device. The resulting reduced flux or biological contamination is stably treated for a long period of time, and the TOC concentration in the water is effectively reduced to obtain treated water having high water quality. Further, the content of concentrated water in the RO membrane separation device is easily and efficiently treated. Method for treating organic matter drainage and processing device.

In recent years, environmental standards and water quality standards have become more and more strict, and high levels of purification are also desired for discharged water. On the other hand, in order to eliminate the shortage of water, it is also desired to develop a highly water treatment technology in order to recycle various types of drainage.

Under such circumstances, since the RO membrane separation treatment can effectively remove impurities (ions, organic substances, fine particles, and the like) in water, it has been used in many fields in recent years. For example, a method in which a wastewater containing a high concentration TOC or a low concentration TOC containing acetone, isopropyl alcohol or the like discharged from a semiconductor manufacturing process is recovered and reused is first subjected to biological treatment to remove the TOC component, and A method of performing RO treatment on a biological treatment water by RO membrane treatment (for example, JP-A-2002-336886).

However, in recent years, the following problems have begun to become apparent: when the biological treatment drainage water is passed to the RO membrane separation device, biodegradation is generated by decomposition of organic matter by microorganisms, which causes the membrane surface of the RO membrane to clog, resulting in a decrease in flux. .

On the other hand, in the case where the TOC-containing drainage water is directly supplied to the RO membrane separation device without using biological treatment, since the TOC concentration flowing into the RO membrane separation device is high, microorganisms are easily formed in the RO membrane separation device. environment of. Therefore, from the purpose of suppressing biological contamination in the RO membrane separation device, a large amount of slime control agent is usually added to the wastewater containing TOC, but since the price of the slime control agent is high, it is sought to be cheaper. A method of inhibiting biological contamination.

In addition, in the drainage discharged from the electronic equipment manufacturing plant, the non-ionic surfactant which is adsorbed on the membrane surface of the RO membrane separation device and may have a reduced flux may be mixed. Conventionally, such non-ionic content is contained. The drainage of surfactants cannot be treated by RO membrane separation.

In order to solve such a problem, when the RO membrane separation apparatus containing high-concentration to low-concentration organic matter discharged from an electronic equipment manufacturing plant or other various fields is treated and recovered, the organic membrane is adsorbed on the membrane surface in the RO membrane separation device. The inventors have proposed the following schemes by first reducing the TOC concentration in the water while obtaining a long-term stable treatment due to a decrease in flux and bio-contamination, and as such a technique, the inventors have proposed the following scheme: To the drain, the scale inhibitor is added in an amount of not less than 5 times by weight of the calcium ions in the organic matter drainage, and before, after or simultaneously with the addition of the scale inhibitor, an alkali reagent is added to the organic-containing wastewater to adjust the pH to 9.5 or more. Then, a method and a device for performing the RO separation treatment are disclosed (JP-A-2005-169372).

In this way, a predetermined amount of the scale inhibitor is added to the water to be treated (hereinafter sometimes referred to as "RO feed water") introduced into the RO membrane separation device, and the pH is adjusted to 9.5 or more, and then the water is supplied to the RO membrane separation device. The following effects can be obtained by preventing the long-term stable treatment of the flux reduction or biological contamination caused by the adsorption of organic substances on the membrane surface in the RO membrane separation device, and effectively reducing the TOC concentration in the water, thereby obtaining high water quality. Treatment of water.

(1) By adjusting the pH of the RO feed water to 9.5 or more, the following effects can be obtained.

Microorganisms cannot survive in an alkaline environment. Therefore, by adjusting the pH of the RO feed water to 9.5 or more, in the RO membrane separation device, although there is a nutrient source, it is possible to create an environment in which microorganisms cannot survive, and it is not necessary to add an expensive slime control agent as in the past. The biological contamination in the RO membrane separation device is suppressed.

Further, it is known that a nonionic surfactant having a reduced flux can be desorbed from the film surface in an alkaline environment, and by adjusting the pH of the RO feed water to 9.5 or more, adsorption of these components to the RO membrane surface can be suppressed. .

(2) By adding a scale inhibitor to the RO feed water in an amount of 5 times or more by weight of calcium ions in the RO feed water, the following effects can be obtained. In the TOC-containing wastewater discharged from an electronic equipment manufacturing plant or the like, calcium ions or the like which cause scaling are rarely mixed. When the pH of the RO feed water is adjusted to a high pH of RO of 9.5 or more, even if a very small amount of calcium ions are mixed, scale formation such as calcium carbonate can be generated, and the RO membrane is directly clogged. Therefore, from the viewpoint of suppressing clogging of the membrane surface due to such fouling, a scale inhibitor is added to the RO feed water in an amount of 5 times or more by weight of calcium ions in the RO feed water to prevent scale formation.

Patent Document 1: JP-A-2002-336886 Patent Document 2: JP-A-2005-169372

According to the technique described in Japanese Laid-Open Patent Publication No. 2005-169372, a wastewater containing a high concentration to a low concentration of organic matter discharged from an electronic equipment manufacturing plant and various other fields, particularly a RO membrane separation device for drainage containing a nonionic surfactant In the RO membrane separation device, the ROC separation device prevents the flux from being adsorbed on the membrane surface due to the adsorption of organic matter on the membrane surface, and the biochemical contamination is stabilized for a long period of time. The TOC concentration in the water can be effectively reduced, and the treated water having high water quality can be obtained. However, the following problems exist.

In the concentrated water (hereinafter sometimes referred to as "RO concentrated water") obtained by adding the anti-fouling agent to the RO feed water and then performing the RO membrane separation treatment, the technique described in JP-A-2005-169372 Since the added scale inhibitor is concentrated, it becomes a scale inhibitor which contains a large amount as a COD component. That is, since the scale inhibitor is not permeable to the RO membrane, it is concentrated on the concentrated water side. In particular, according to the technique of JP-A-2005-169372, a large amount of scale inhibitor is added in an amount of 5 times or more by weight of calcium ions in the RO feed water, and RO membrane separation treatment is performed thereon, and the obtained RO concentrated water is obtained. Contains a large amount of scale inhibitor.

Usually, the RO concentrated water is sent to a wastewater treatment process, and is discharged after biological treatment and coagulation sedimentation treatment, but in general, the scale inhibitor is difficult to remove by coagulation sedimentation treatment and biological treatment, in addition, the knot is The scale inhibitor is also a substance that hinders the aggregation reaction. Therefore, if the RO concentrated water containing a large amount of the scale inhibitor is sent to the wastewater treatment process in this way, in addition to the increase in the load of the wastewater treatment process, the COD value in the discharged water may be increased to lower the water quality.

In view of the above, it is an object of the present invention to provide a method and a processing apparatus for containing organic matter drainage which effectively reduce the TOC value including the COD value of such RO concentrated water and prevent adverse effects of RO concentrated water on drainage treatment and the like.

The method for treating organic matter-containing wastewater according to the first aspect of the invention includes the following process: a process for adding a scale inhibitor to a scale containing an organic matter, and a scale addition preventing agent; a reverse osmosis membrane separation process comprising the organic matter drainage supply to the reverse osmosis membrane separation device, separated into permeate water and concentrated water; and a pH adjustment process for adjusting the pH of the organic wastewater supplied to the reverse osmosis membrane separation device to 9.5 or more; There is an oxidation treatment process in which ozone is added to the concentrated water to oxidize the concentrated water.

The method for treating organic matter-containing wastewater according to Item 2, characterized in that in the first aspect, the oxidation treatment process is a process for promoting oxidation treatment using ozone and hydrogen peroxide in combination.

The method for treating organic matter-containing wastewater according to the third aspect, wherein in the first or second aspect, the pH of the treated water in the oxidation treatment process is 5.6 to 8.6.

According to a fourth aspect of the invention, in the first aspect or the second aspect, the alkali reagent is added to the concentrated water so that the pH of the water in the oxidation treatment process reaches 9.8 to 11 Alkali addition process.

The method of treating organic matter containing water according to the fifth aspect of the invention, characterized in that, in any one of items 1 to 4, the activated carbon treatment process for bringing the treated water in the oxidation treatment process into contact with the activated carbon.

According to a sixth aspect of the present invention, in the method of adding the scale preventing agent, the scale preventing agent is added to the organic matter draining water in any one of the items 1 to 5. The amount is 5 times or more by weight of the calcium ions contained in the organic matter drainage.

According to a seventh aspect of the invention, in the method of the present invention, in the sixth aspect, in the scale inhibitor preparation process, a scale inhibitor is added to the organic matter-containing drain, and the amount is the organic matter. 5 to 50 times the weight of calcium ions in the drainage.

The method of claim 8, wherein the reverse osmosis membrane of the reverse osmosis membrane separation apparatus has a reverse osmosis membrane at 1.47 MPa, 25 ° C, and a pH of 7 Under the conditions of the reverse osmosis membrane separation treatment of the 1500 mg/L saline solution, the salt rejection rate is 95% or more, and the polyvinyl alcohol-based low-pollution reverse osmosis membrane having a desalination property.

According to a ninth aspect of the invention, in the method of any one of the first to eighth aspects, the pH of the organic-containing water drain is adjusted to 10.5 to 12 in the pH adjustment process.

The method of treating organic matter-containing wastewater according to claim 10, wherein, in any one of items 1 to 9, the organic matter-containing drainage is subjected to a cation exchange treatment before the addition of the scale inhibitor.

The apparatus for treating organic matter-containing water according to the eleventh aspect of the present invention, comprising: a scale inhibitor preparation unit that adds a scale inhibitor to the organic matter drain; and an organic matter to which the scale inhibitor is added a reverse osmosis membrane separation device that separates the water into a permeated water and concentrated water; and a pH adjustment unit that adjusts the pH of the organic wastewater supplied to the reverse osmosis membrane separation device to 9.5 or more; wherein the ozone is added to the concentrated water An oxidation treatment unit for oxidizing the concentrated water.

The apparatus for treating organic matter drainage according to Item 12, characterized in that in the eleventh aspect, the oxidation treatment unit is an oxidation-oxidation treatment unit in which ozone and hydrogen peroxide are used in combination.

The apparatus for treating organic matter drainage according to Item 13, wherein the pH of the treated water in the oxidation treatment unit is 5.6 to 8.6.

The apparatus for treating organic matter according to Item 14, wherein the item 11 or 12 has an alkali addition agent added to the concentrated water so that the pH of the water in the oxidation treatment unit reaches 9.8 to 11. unit.

The apparatus for treating organic matter according to any one of items 11 to 14, wherein the activated carbon column is introduced into the treated water of the oxidation treatment unit.

The apparatus for treating organic matter according to any one of the items 11 to 15, wherein the scale inhibitor preparation unit adds a scale inhibitor to the organic matter drain. The amount is 5 times or more by weight of the calcium ions contained in the organic matter drainage.

According to a sixth aspect of the invention, in the fouling preventing agent adding unit, the scale preventing agent is added to the organic matter draining water in an amount of the organic matter. 5 to 50 times the weight of calcium ions in the drainage.

The apparatus of claim 18, wherein the reverse osmosis membrane of the reverse osmosis membrane separation apparatus has a reverse osmosis membrane at 1.47 MPa, 25 ° C, and a pH of 7 The polyvinyl alcohol-based low-pollution reverse osmosis membrane having a desalination performance of 95% or more in the case of performing reverse osmosis membrane separation treatment of 1500 mg/L of saline solution under the conditions of the reverse osmosis membrane.

The apparatus for treating organic matter according to any one of items 11 to 18, wherein the pH of the organic matter-containing water is adjusted to 10.5 to 12 in the pH adjusting unit.

According to a ninth aspect of the present invention, in the apparatus of claim 11, the cation exchange for the cation exchange treatment of the organic matter drainage supplied to the scale inhibitor addition unit tower.

According to the method and the apparatus for treating organic matter-containing water according to the present invention, the wastewater containing the high-concentration to low-concentration organic matter discharged from the electronic equipment manufacturing plant and various other fields, particularly the RO membrane for drainage containing the nonionic surfactant When the separation device performs the treatment and recovery, the RO membrane separation device can prevent the flux from being lowered due to the adsorption of organic substances on the membrane surface, and the bio-contamination can be stably treated for a long period of time, and the TOC concentration in the water can be effectively reduced to obtain a high-quality treatment. water. Moreover, it is also possible to easily and efficiently treat the organic substance including the scale inhibitor in the RO concentrated water to reduce the load on the subsequent drainage treatment process.

In other words, in the present invention, since the scale inhibitor is added to the RO feed water and the pH is adjusted to 9.5 or more, water is supplied to the RO membrane separation device, and as described above, the biological contamination in the RO membrane separation device can be suppressed. And inhibit the membrane surface blockage caused by scaling.

In addition, by performing ozone treatment on the RO concentrated water obtained by adding the scale inhibitor to the RO water supply, the oxidative decomposition and removal of the concentrated water including the COD component derived from the scale inhibitor in the RO concentrated water can be effectively carried out. Organic matter (TOC). Further, since the reaction speed by the oxidation treatment by ozone is faster than that of the biological treatment, the apparatus can be downsized, and the installation space of the apparatus can be reduced.

The ozone oxidation treatment according to the present invention may be a combined oxidation treatment with ozone and hydrogen peroxide (Items 2 and 11).

In the ozone oxidation treatment or the combined oxidation treatment of ozone and hydrogen peroxide, the TOC in the concentrated water reacts with a hydroxyl radical derived from ozone or hydrogen peroxide to first become an oxygen compound such as an organic acid. Since the pH of the water to be treated is lowered by the formation of the organic acid, the reactivity of ozone or the like is lowered even if ozone or the like is continuously added in a state where the pH is lowered. Therefore, in order to further decompose and remove the TOC, it is necessary to add a large amount of ozone. Therefore, in order to prevent such a decrease in reactivity due to a decrease in pH, it is usually necessary to add an alkali reagent to the raw water of the ozone oxidation treatment to make the pH alkaline.

In the present invention, the high-concentration RO concentrated water obtained by separating and treating the high-pH organic membrane-containing RO membrane adjusted to a pH of 9.5 or higher is subjected to such ozone oxidation treatment or oxidation treatment. It is not necessary to add an alkali reagent for preventing such a decrease in reactivity due to a decrease in pH caused by the formation of an organic acid.

However, in the ozone-concentrated concentrated water, in the ozone oxidation treatment or the oxidation-promoting treatment, the pH is lowered by the formation of the organic acid, and when the pH reaches a pH neutral range of about 5.6 to 8.6, the reaction is difficult to proceed, so the pH is not It will be further reduced, and as a result, neutral treated water can be stably obtained. The pH-neutral treated water can be directly discharged without pH adjustment (items 3 and 13).

However, in the present invention, the pH of the water in the ozone oxidation treatment or the oxidation treatment is not lowered even if the pH of the organic acid is formed, and the alkali reagent is added to the concentrated water before the ozone oxidation treatment or the oxidation treatment is promoted. When the ozone or hydroxyl radical is highly reactive and has a basic pH of about 9.8 to 11, the oxidation reaction can be promoted, and the TOC can be efficiently decomposed and removed using a small amount of ozone (items 4 and 14).

After such an ozone oxidation treatment or an oxidation treatment is promoted, the oxidizing agent (ozone, hydrogen peroxide) remaining in the treated water can be removed by treating the oxidized water with activated carbon (Items 5 and 15). The TOC remaining in water can also be removed by this activated carbon treatment.

In the present invention, when the amount of the scale inhibitor added to the organic-containing wastewater is too small, a sufficient scale preventing effect cannot be obtained. Therefore, the amount of the scale-preventing agent added to the organic-containing wastewater is preferably RO water supply. More than 5 times the weight of calcium ions (items 6, 16).

In the present invention, even when the scale inhibitor is a salt such as a sodium salt, the amount of the scale inhibitor added is a value obtained by converting the acid.

Further, in the present invention, in particular, as the RO membrane, it is preferred to carry out an RO membrane separation treatment using an RO membrane having an RO membrane of 1500 mg/L of saline at 1.47 MPa, 25 ° C, and pH 7; The salt rejection rate (hereinafter referred to as "salt elimination rate") at the time of the separation treatment is a polyvinyl alcohol-based low-pollution RO membrane having a desalting performance of 95% or more (Items 8 and 18). The reason why such a low-pollution RO membrane is preferably used is as follows.

In other words, the RO film for low-pollution is superior in the anti-contamination property because the chargeability of the surface of the film is improved and the hydrophilicity is improved as compared with the aromatic polyimide film which is generally used. However, the water-repellent effect is reduced with respect to water containing a large amount of nonionic surfactant, and the flux decreases with time.

On the other hand, in the present invention, by adjusting the pH of the RO feed water to 9.5 or more, it is possible to desorb the nonionic surfactant having a reduced RO membrane flux from the film surface, so even if the commonly used aroma is used In the case of a polyamide membrane, it is also possible to suppress an extreme decrease in flux. However, when the concentration of the nonionic surfactant in the RO feed water is high, the effect is lowered, and the long-term use causes a decrease in the flux.

Therefore, in the present invention, in order to solve such a problem, it is preferable to combine the above-described polyvinyl alcohol-based low-pore RO membrane having specific desalting performance and the condition that the pH of the RO feed water is adjusted to 9.5 or more to pass water. Even for RO feed water containing a high concentration of nonionic surfactant, it does not cause a decrease in flux, and stable operation can be performed for a long period of time.

In the present invention, in order to perform more efficient processing, the following conditions are preferably employed.

(1) The pH of the RO feed water is preferably adjusted to above 10.5, especially to 10.5~12 (Items 9, 19).

(2) The amount of the scale inhibitor is 5 to 50 times the calcium ion concentration (items 7, 17).

(3) When the calcium ion concentration of the RO feed water is high, as a pretreatment for adding a scale inhibitor, a cation exchange treatment is performed to remove calcium (Items 10 and 20).

Hereinafter, embodiments of the method and apparatus for treating organic matter containing water of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a system diagram showing an embodiment of a method and a processing apparatus for containing organic matter drainage according to the present invention. In the figure, P ₁ , P ₂ , and P ₃ are pumps.

In Fig. 1, after the scale inhibitor is added to the raw water (containing the organic matter drain) introduced through the raw water tank 1, the pH is adjusted to 9.5 or more by adding an alkali reagent, and then introduced into the RO membrane separation device 2 for RO membrane separation treatment. .

As a scale inhibitor which is added to raw water, it is preferable to use a chelate-type scale inhibitor such as ethylenediaminetetraacetic acid (EDTA) or ammonia triacetic acid (NTA) which easily forms a complex with metal ions after dissociation in the alkali range. However, in addition to this, it is also possible to use (meth)acrylic acid polymers and salts thereof, low molecular weight polymers such as maleic acid polymers and salts thereof, ethylenediaminetetramethylenephosphonic acid and salts thereof, and hydroxyl groups. Phosphonic acid and phosphonates of ethylene diphosphonic acid and its salts, nitrilotrimethylene phosphonic acid and its salts, phosphinium butane tricarboxylic acid and its salts, hexametaphosphoric acid and its salts, three Inorganic polymeric phosphoric acid such as polyphosphoric acid and its salt, and inorganic polymeric phosphate. These scale inhibitors may be used alone or in combination of two or more.

In the present invention, the amount of the scale inhibitor to be added is preferably 5 times or more by weight of the calcium ion in the raw water (water to which the scale inhibitor is added). When the amount of the scale inhibitor is less than 5 times the weight of the calcium ion in the raw water, the effect of adding the scale inhibitor cannot be sufficiently obtained. Since the excessive addition of the scale inhibitor is not preferable from the viewpoint of the cost of the medicament, it is preferably 5 to 50 times the weight of the calcium ion in the raw water.

The raw water to which the scale inhibitor is added is added, and then the pH is adjusted to 9.5 or more, preferably 10 or more, more preferably 10.5 to 12 by adding an alkali reagent. For example, after adjusting the pH to 10.5 to 11, the membrane is introduced into the RO membrane separation device 2 . The alkali reagent to be used herein is, for example, sodium hydroxide, potassium hydroxide or the like, and is not particularly limited as long as it can adjust the pH of the raw water to 9.5 or more.

The RO membrane as the RO membrane separation device 2 is a substance having alkali resistance, and examples thereof include a polyether guanamine composite membrane, a polyvinyl alcohol composite membrane, and an aromatic polyamide membrane. However, for the reasons described above, It is preferable to use a polyvinyl alcohol-based low-pore RO membrane having a salt rejection of 95% or more. The RO membrane may be any type of membrane such as a spiral type, a hollow fiber type, or a tubular type.

The permeated water of the RO membrane separation device 2 is adjusted to pH 4 to 8 by adding an acid, and if it is further subjected to activated carbon treatment or the like as needed, it is reused or discharged. The acid to be used herein is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid and sulfuric acid.

On the other hand, after the concentrated water of the RO membrane separation device 2 is stored in the RO concentration tank 3, hydrogen peroxide (H ₂ O ₂ ) and/or an alkali reagent are added as needed, and then sent to the ozone reaction tower 4 for oxidation treatment. .

It is not always necessary to add hydrogen peroxide to the concentrated water. However, by adding hydrogen peroxide, it is possible to increase the oxidative decomposition efficiency by generating a hydroxyl radical which is stronger than the oxidizing power of ozone, and it is possible to further reduce the amount of ozone added. Hydrogen peroxide is preferably added.

The position at which hydrogen peroxide is added may be either before the concentrated water is contacted with ozone or after the addition of the alkali reagent. The addition of hydrogen peroxide is preferably carried out in a line to the concentrated water delivery line as shown in Fig. 1. However, in this case, a stirring unit such as a line mixer is preferably provided.

In addition, the amount of the hydrogen peroxide to be added is not particularly limited, and is appropriately determined depending on the water quality of the concentrated water, the required treated water quality, and the like, and is usually about 1 to 10 times the weight of the TOC in the concentrated water.

The ozone reaction column 4 is not particularly limited as long as it can maintain the alkaline range in which the reactivity of ozone or hydroxyl radicals is high, and the concentrated water absorbs ozone efficiently, and the reaction proceeds, as shown in FIG. The concentrated water is dispersed from the water-spreading plate 5 provided in the upper portion of the reaction tower 4, and the ozone transported from the ozone generator 6 is diffused through the diffusing pipe 7 at the lower portion of the tower, and may be opened by a mechanical mixer. sink. Further, it may be an in-flow ozone supply unit such as a line agitator or a vortex pump provided in the pipe. However, in order to bring the ozone and the concentrated water into contact sufficiently to cause the TOC in the concentrated water to be highly oxidized, it is preferred to provide a reaction vessel.

In the present invention, the pH of the water in the ozone reaction column 4 or the effluent water of the ozone reaction column 4 reaches 9 by the addition of the alkali reagent to the RO concentrated water introduced into the ozone reaction column 4 or to the ozone reaction column 4. ~12, more preferably 9.8~11, thereby promoting the oxidation reaction using ozone. When the adjusted pH value is less than 9, the effect of improving the oxidative decomposition efficiency due to the addition of the alkali reagent cannot be sufficiently obtained. However, when the pH is too high, the pH of the treated water becomes high, which is relatively unfavorable for subsequent biological treatment or discharge.

As the alkali reagent for adjusting the pH, an inorganic base reagent such as sodium hydroxide or potassium hydroxide can be used.

However, the alkali reagent is not necessarily required to be added. As described above, the RO concentrated water of the present invention usually has a high pH of about pH 10 to 12, and even if it is directly supplied to the ozone oxidation treatment or the oxidation treatment, Can get sufficient reaction efficiency. Therefore, in this case, a neutral treatment water having a pH of about 5.6 to 8.6 is obtained, and the treated water can be directly discharged, or even in the case of a subsequent biological treatment process, the pH adjustment is not particularly performed. Directly for biological treatment.

The method of adding ozone is not particularly limited, and as shown in FIG. 1, it can be carried out in such a manner that ozone from the ozone generator 6 is diffused in the ozone reaction column 4 through the diffusing pipe 7 or injected by an ejector. Common methods such as methods. Further, it is also possible to use ozone to dissolve ozone therein by water or the like, and to add it as ozone water.

The amount of ozone added varies depending on the quality of the concentrated water and the amount of hydrogen peroxide added thereto, and is usually about 1 to 50 times the weight of the TOC of the concentrated water.

In Fig. 1, the discharged water from the ozone reaction column 4 is introduced into the activated carbon column 8, and after the residual ozone or hydrogen peroxide is removed, it is discharged as treated water to the outside of the system, discharged or further subjected to biological treatment. The treatment conditions in the activated carbon column 8 are appropriately determined depending on the residual amount of ozone or hydrogen peroxide in the effluent water of the ozone reaction column 4. The TOC remaining in the ozone-treated water can be further removed by the activated carbon treatment.

The treated water thus obtained can be discharged after adjusting the pH directly or as needed, in the case where the TOC concentration is sufficiently lowered. Further, in the case where the TOC of the treated water is not sufficiently lowered, it may be mixed with other drains and sent to a wastewater treatment process for treatment, or it may be passed to the deionization apparatus to further remove the TOC.

In Fig. 1, an ion exchange column 9 is provided as a deionization device. As the deionization device, an ion exchange device, a reverse osmosis membrane device, an electric regenerative deionization device, or the like can be used. The ion exchange apparatus may be a mixed bed type ion exchange column in which a cation exchange resin and an anion exchange resin are mixed in a mixed state, or a 2 bed 3 column type, 4 bed 5 column type desalination in which two kinds of resins are filled in each column. Device. When the water flowing out of the activated carbon column is passed to the deionization apparatus, the ionic TOC in the water is removed, and treated water containing almost no TOC can be obtained. The treated water can be discharged or recycled.

According to the present invention, as shown in Fig. 1, by adding a predetermined amount of the scale inhibitor to the raw water and adjusting the pH to 9.5 or more and then performing the RO membrane separation treatment, the flux in the RO membrane separation device can be prevented from being lowered. The stable treatment can be carried out for a long period of time, and high-quality water treated with highly removed TOC is obtained. Further, the RO concentrated water obtained by the RO membrane separation treatment is subjected to ozone oxidation treatment or oxidation treatment, whereby the organic substance in the concentrated water can be highly oxidatively decomposed and removed.

Fig. 1 shows an example of an embodiment of the present invention, and is not limited to any of the illustrated embodiments as long as it does not exceed the gist of the present invention. In Fig. 1, after adding a scale inhibitor to raw water, an alkali reagent is added to adjust the pH. However, an alkali agent may be added to the raw water to adjust the pH, and then a scale inhibitor may be added, and pH adjustment may be simultaneously performed. And the addition of scale inhibitors. Further, the treatment by the RO membrane separation device is not limited to one-stage treatment, and may be two-stage or more multi-stage treatment. In addition, in the case of the TOC-containing drain or the like discharged from the electronic equipment manufacturing plant, there are few cases in which calcium ions or the like which cause scaling are mixed. However, when calcium ions or the like are mixed in the raw water, scaling prevention can be added. Before the agent, a cation exchange column for removing calcium ions is provided to remove calcium in advance. Further, a mixing tank for adjusting the pH or adding a scale inhibitor may be provided.

Further, when the RO concentrated water is treated, when the RO membrane separation apparatus performs the multistage treatment of two or more stages, the RO concentrated water of the RO membrane separation apparatus of the first stage may be subjected to such oxidation treatment, or may be used for other treatments. The RO concentrated water was subjected to the same treatment.

Further, the ozone or hydrogen peroxide remaining in the ozone oxidation treatment or the oxidation treatment is not limited to the activated carbon column, and may be carried out by adding a reducing agent such as sodium hydrogen sulfite. However, in terms of removing residual TOC, activated carbon treatment is preferred.

In the present invention, the RO concentrated water supplied to the ozone oxidation treatment or the oxidation-promoting treatment preferably contains a TOC which is a biodegradable scale inhibitor or a surfactant, and the ozone oxidation treatment or the oxidation treatment of the present invention is effectively exerted. effect. However, it may contain a scale inhibitor which is easily biodegradable, and may contain organic substances other than the scale inhibitor. In either case, they are oxidatively decomposed by ozone, thereby reducing the load of subsequent biological treatment and making the aeration tank The set area is reduced. Or you can get good water discharge.

[Examples]

The invention will be more specifically described below by way of examples.

Example 1

The drainage having a TOC concentration of 5 mg/L and a calcium ion concentration of 10 mg/L mainly composed of a surfactant was used as raw water, and was treated by the apparatus shown in Fig. 1 . First, an EDTA-based scale inhibitor (ethylenediaminetetraacetic acid sodium salt) is added to the raw water in an amount of 5 times the calcium ion concentration of the raw water, and then NaOH is added to bring the pH to 10.5, using an RO membrane separation device (Nitto The low-pressure aromatic polyamine type RO membrane "ES-10" manufactured by the electrician was subjected to RO membrane separation treatment under the conditions of a water flow rate of 80 L/h and a recovery rate of 75%.

To the RO concentrated water obtained by the RO membrane separation treatment, hydrogen peroxide was added in an amount of 1.2 times the TOC, and then ozone was added in an amount of 10 times the TOC. Then, water is passed through the activated carbon column under the condition of passing water SV10/h, and the effluent water of the activated carbon column is passed through the ion exchange column under the condition of flowing water SV20m/h to obtain treated water, and the ion exchange is performed. The column was mixed with DIAION SK1B (product of Mitsubishi Chemical Corporation) as a cation exchange resin and Lewatit M500 (product of BAYER Co., Ltd.) as an anion exchange resin in a 1:1 (by weight) mixture.

The pH, TOC concentration of the RO concentrated water and the pH, TOC concentration and TOC removal rate of the ozone treated water (the effluent water of the ozone reaction tower), and the pH, TOC concentration and TOC removal rate of the effluent water of the activated carbon column were studied. The pH, TOC concentration, and TOC removal rate of the treated water (the effluent water of the ion exchange column) were shown in Table 1.

Example 2

The treatment was carried out in the same manner as in Example 1 except that hydrogen peroxide was not added to the RO concentrated water, and the pH, TOC concentration, and TOC removal rate of the ozone-treated water (outflow water of the ozone reaction column) and the outflow of the activated carbon column were examined. The pH, TOC concentration, and TOC removal rate of water, and the pH, TOC concentration, and TOC removal rate of treated water (exit water of the ion exchange column) are shown in Table 1.

Example 3

The pH, TOC concentration, and TOC removal rate of the ozone-treated water (outflow water of the ozone reaction column) were examined in the same manner as in Example 1 except that the amount of the alkali added was increased so that the pH of the ozone-treated water reached 10, and The pH, TOC concentration, and TOC removal rate of the effluent water of the activated carbon column, and the pH, TOC concentration, and TOC removal rate of the treated water (the effluent water of the ion exchange column) are shown in Table 1.

As apparent from Table 1, according to the present invention, the TOC in the RO concentrated water can be highly removed.

Industrial application possibilities

The present invention can be effectively applied to water treatment for discharge or recovery and reuse of drainage water containing high-concentration to low-concentration TOC discharged from the field of electronic device manufacturing, semiconductor manufacturing, and various other industrial fields.

1. . . Original sink

2. . . RO membrane separation device

3. . . RO concentrated sink

4. . . Ozone reaction tower

5. . . Water board

6. . . Ozone generator

7. . . Air pipe

8. . . Activated carbon tower

9. . . Ion exchange tower

P ₁ , P ₂ , P ₃ . . . Pump

Fig. 1 is a system diagram showing an embodiment of a method and a processing apparatus for containing organic matter drainage according to the present invention.

1. . . Original sink

2. . . RO membrane separation device

3. . . RO concentrated sink

4. . . Ozone reaction tower

5. . . Water board

6. . . Ozone generator

7. . . Air pipe

8. . . Activated carbon tower

9. . . Ion exchange tower

P ₁ , P ₂ , P ₃ . . . Pump

Claims (16)

A method for treating organic matter drainage, comprising the steps of: adding a scale inhibitor to a scale containing agent to the organic matter drain; and supplying the organic matter drain to which the scale inhibitor is added to the reverse osmosis a membrane separation device, which is separated into a reverse osmosis membrane separation process of permeated water and concentrated water; and a pH adjustment process for adjusting the pH of the organic-containing drainage supplied to the reverse osmosis membrane separation device to 9.5 or more; wherein An oxidation treatment process for oxidizing the concentrated water by adding ozone to the water, the oxidation treatment process is a combined oxidation treatment process using ozone and hydrogen peroxide, wherein the hydrogen peroxide is added to the concentrated water before the oxidation treatment, and has An alkali addition process is carried out by adding an alkali reagent to the concentrated water so that the pH of the water in the oxidation treatment process reaches 9.8-11. The method for treating organic matter drainage according to claim 1, wherein the pH of the treated water in the oxidation treatment process is 5.6 to 8.6. The method for treating organic matter-containing wastewater according to claim 1, characterized in that the activated carbon treatment process for bringing the treated water of the oxidation treatment process into contact with activated carbon is provided. Treatment of organic matter-containing drainage as described in item 1 of the patent application scope In the method for adding a scale inhibitor, the scale inhibitor is added to the organic wastewater to be contained in an amount of 5 times by weight or more of calcium ions in the organic wastewater. The method for treating organic matter drainage according to claim 4, wherein in the scale inhibitor preparation process, calcium ions in the organic matter-containing drainage are added to the organic-containing wastewater. 50 times the weight of the scale inhibitor. The method for treating organic matter drainage according to claim 1, wherein the reverse osmosis membrane of the reverse osmosis membrane separation device has a pressure of 1500 mg/at at 1.47 MPa, 25 ° C, and pH 7. The sodium chloride-based low-pollution reverse osmosis membrane having a desalination performance of 95% or more in the case of the reverse osmosis membrane separation treatment of the aqueous solution of L. The method for treating organic matter drainage according to claim 1, wherein in the pH adjustment process, the pH of the organic-containing drainage is adjusted to 10.5 to 12. The method for treating organic matter-containing wastewater according to claim 1, wherein the organic matter-containing drainage is subjected to a cation exchange treatment before the addition of the scale inhibitor. A treatment device containing organic matter drainage, comprising: a scale inhibitor preparation unit for adding a scale inhibitor to an organic matter drain; and separating the organic matter drain to which the scale inhibitor is added to permeate water and concentrating a reverse osmosis membrane separation device for water; and a pH containing organic matter supplied to the reverse osmosis membrane separation device a pH adjustment unit adjusted to 9.5 or more; wherein, there is an oxidation treatment unit that adds ozone to the concentrated water to oxidize the concentrated water, and the oxidation treatment unit is a combined oxidation treatment unit using ozone and hydrogen peroxide, wherein The hydrogen peroxide is added to the concentrated water before the oxidation treatment, and has an alkali addition unit that adds an alkali reagent to the concentrated water so that the pH of the water in the oxidation treatment unit reaches 9.8 to 11. The apparatus for treating organic matter drainage according to claim 9, wherein the pH of the treated water in the oxidation treatment unit is 5.6 to 8.6. The apparatus for treating organic matter drainage according to claim 9, which is characterized in that the activated carbon column is provided with treated water introduced into the oxidation treatment unit. The apparatus for treating organic matter drainage according to claim 9, wherein the scale inhibitor addition unit adds 5 times of calcium ions in the organic-containing drainage to the organic-containing wastewater. A scale inhibitor above the weight. The apparatus for treating organic matter drainage according to claim 12, wherein the scale inhibitor preparation unit adds calcium ions in the organic matter-containing drainage to the organic-containing wastewater. 50 times the weight of the scale inhibitor. The apparatus for treating organic matter drainage according to claim 9, wherein the reverse osmosis membrane of the reverse osmosis membrane separation device has a pressure of 1500 mg/at 1.47 MPa, 25 ° C, and pH 7. L The salt water having a desalination performance of 95% or more in the reverse osmosis membrane separation treatment is a polyvinyl alcohol-based low-pollution reverse osmosis membrane. The apparatus for treating organic matter drainage according to claim 9, wherein the pH adjusting unit adjusts the pH of the organic-containing drainage to 10.5 to 12. The apparatus for treating organic matter drainage according to claim 9, wherein the cation exchange column containing the organic matter drainage and cation exchange treatment is supplied to the scale inhibitor addition unit.