KR20070096859A - Method for treating waste water containing surfactant - Google Patents

Abstract

A method for effectively preventing the deterioration of a membrane flux in a method of decomposing a surfactant contained in wastewater by performing an ozone oxidation process prior to a membrane process is provided. In a method of sequentially treating wastewater containing a surfactant by an oxidation process and a membrane process, a method for treating wastewater containing a surfactant is characterized in that: the oxidation process is a process of contacting the wastewater with ozone under alkaline conditions to oxidize a surfactant contained in the wastewater; and the membrane process is a process of filtering alkaline oxidized water discharged from the oxidation process using a membrane. The membrane process is a reverse membrane process. The oxidation process is an accelerated oxidation process using ozone and hydrogen peroxide. The method further comprises an oxidizer removal process of removing an oxidizer remained in water that has passed through the oxidation process, and water that has passed through the oxidizer removal process is introduced into the membrane process.

Description

Treatment method of surfactant-containing wastewater {METHOD FOR TREATING WASTE WATER CONTAINING SURFACTANT}

BRIEF DESCRIPTION OF THE DRAWINGS It is a system diagram which shows embodiment of the treatment method of surfactant containing wastewater of this invention.

<Description of Drawing>

1: ozone reaction tower

2: RO membrane separation device

3: ozone generator

4: activated carbon filtration tower

TECHNICAL FIELD This invention relates to the method of processing wastewater containing surfactant which arises in the field of electronic device manufacture, such as a semiconductor and a liquid crystal.

In the ultrapure water production apparatus used in the field of electronic device manufacturing such as semiconductors and liquid crystals, reverse osmosis (RO) membrane separation devices are usually provided as an organic material (TOC) removal device. In particular, RO membrane separation apparatuses are widely used in wastewater recovery systems in which TOC is removed from low-density TOC-containing wastewater of about TOC water mg / L and recovered and reused as raw water of an ultrapure water production system.

However, when the raw water of the RO membrane separation device (hereinafter sometimes referred to as "RO raw water") contains a nonionic surfactant as a TOC component, the RO membrane of the RO membrane separation device is heavily contaminated by the nonionic surfactant, There is a problem that the amount of water to be treated decreases due to the decrease of the membrane plus.

Conventionally, in order to solve this problem of membrane contamination, generally, a method of installing an activated carbon adsorption tower and adsorbing and removing a nonionic surfactant at all stages of a RO membrane separation device has been adopted. There is a problem that occurs.

Regarding the problem of RO membrane contamination by this nonionic surfactant, Non-Patent Document 1 reports that when a nonionic surfactant is decomposed to some extent and loses its surfactant activity, the decomposed substance becomes RO membrane contamination. It is.

In addition, Patent Document 1 proposes a method for separating RO membranes after ozone oxidation of raw water in order to prevent RO membrane contamination. In this patent document 1, although the pH of ozone oxidation treatment water is adjusted to be 8-10, RO membrane separation process is performed after adding acid to this pH alkaline ozonation treatment water, making it pH neutral.

Moreover, even if it is waste water containing surfactant, if it is pH alkaline conditions, it is known that RO membrane is difficult to be polluted, and patent document 2 has proposed the method of isolate | separating RO membrane under alkaline conditions of pH 9.5 or more in TOC containing waste water.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2005-230731

[Patent Document 2] Japanese Unexamined Patent Publication No. 2005-169372

[Non-Patent Document 1] Collection of Seminars of Separation Technology Conference (issued June 4, 2004)

In the method of Patent Literature 1, ozone oxidation is performed prior to RO membrane separation, but since RO membrane separation is performed under pH neutral conditions, microorganisms propagate in the RO membrane separation apparatus to contaminate the membrane surface, and the membrane flux over time. There is a problem that is lowered.

In the method of patent document 2, since RO membrane is isolate | separated on pH alkaline conditions, surfactant is hard to adhere to a membrane surface, and the fall of a membrane flux can be prevented, but the fall of a flux in case of continuing operation for a long time cannot be avoided, In addition, a flux fall may occur early by surfactant concentration in RO water supply. Therefore, it is preferable to remove surfactant in RO water supply as much as possible.

The present invention has been made in view of the above-described conventional situation, and an object of the present invention is to provide a method of preventing a flux decrease of a membrane and continuing a stable treatment for a long time in membrane separation treatment of wastewater containing a surfactant.

In particular, the present invention relates to a method of effectively preventing a decrease in membrane flux in a method of decomposing a surfactant in wastewater by ozone oxidation prior to the membrane separation treatment.

The treatment method of the surfactant-containing wastewater of the present invention (claim 1) is a method of sequentially treating the surfactant-containing wastewater by an oxidation process and a membrane separation process, wherein the oxidation process is performed by contacting the wastewater with ozone under alkaline conditions. It is a process of oxidizing surfactant in waste water, The said membrane separation process is a process of carrying out the membrane separation of the alkaline oxidation treated water discharged | emitted by the said oxidation process.

The treatment method of the surfactant containing wastewater of Claim 1 WHEREIN: It is characterized by the oxidation-processed water discharged in the said oxidation process in pH 9-12, and containing residual TOC.

The treatment method of the surfactant-containing wastewater of claim 3 is characterized in that the residual TOC concentration in the oxidation-treated water is 2 to 20 mg / L according to claim 2.

The treatment method of the surfactant-containing wastewater of claim 4 is characterized in that the membrane separation step is a reverse osmosis membrane separation step according to any one of claims 1 to 3.

The treatment method of the surfactant-containing wastewater of claim 5 is, according to any one of claims 1 to 4, wherein, in the oxidation step, 2 to 10 times as much ozone is supplied to the wastewater relative to the surfactant in the surfactant-containing wastewater. Characterized in that.

The treatment method of the surfactant containing wastewater of Claim 6 is the said oxidation process as described in any one of Claims 1-5 characterized by the accelerated oxidation process by combined use of ozone and hydrogen peroxide.

The treatment method of the surfactant-containing wastewater of claim 7 includes an oxidizing agent removing step of removing an oxidizing agent remaining in the water having passed through the oxidizing step, and the water having passed through the oxidizing agent removing step according to any one of claims 1 to 6. It is characterized in that it is introduced into the membrane separation process.

The treatment method of the surfactant containing wastewater of Claim 8 is characterized in that the said oxidizing agent removal process is an activated carbon treatment process of Claim 7.

According to the treatment method of the surfactant-containing wastewater of the present invention, before the membrane separation treatment, ozone oxidation is carried out under alkaline conditions to oxidatively decompose the surfactant in the wastewater, and the alkaline oxidation treated water is subjected to the membrane separation treatment. It is possible to continue the stable processing for a long time by preventing the deterioration of.

That is, when the membrane separation treatment in the pH neutral conditions as in the method of Patent Literature 1, the membrane surface is contaminated due to the growth of microorganisms and the membrane flux is reduced, but in the present invention, without neutralizing the oxidized water, it is alkaline or further if necessary. Since alkali is added to a predetermined high pH to feed the membrane separation device, contamination by microorganisms in the membrane separation device can be suppressed, and a decrease in flux for a long time can be prevented.

In addition, although the method of patent document 2 makes pH alkaline, and prevents membrane surface adhesion of surfactant, since surfactant exists, the fall of the flux by surfactant is unavoidable in long-term operation, and surfactant concentration is high. In this case, there is a problem of early flux reduction, but this problem is solved because the present invention can decompose and remove the surfactant in the wastewater by performing ozone oxidation under alkaline conditions prior to membrane separation.

The oxidation process in the present invention may be an accelerated oxidation process by using a combination of ozone and hydrogen peroxide (claim 6).

In the ozone oxidation treatment or the accelerated oxidation treatment using ozone and hydrogen peroxide, the TOC in the waste water reacts with hydroxy radicals from ozone or hydrogen peroxide and first changes into an acidic compound such as an organic acid. Since the generation of the organic acid causes the pH of the water to be treated to decrease, even if ozone or the like is continuously added while the pH is lowered, the reactivity of ozone or the like decreases. For this reason, the addition of a large amount of ozone is required for better decomposition and removal of TOC. In the present invention, the pH of the water of the oxidation process (or the accelerated oxidation process) or the effluent water of the oxidation process (or the accelerated oxidation process) is such that the pH of the alkali region of high reactivity of ozone or hydroxy radicals, preferably pH 9-12, is high. By adjusting, the TOC containing surfactant can be decomposed efficiently with little ozone usage.

Ozone oxidation or ozone accelerated oxidation under alkaline conditions in the present invention not only reduces the amount of ozone used as described above, but also has the following effects.

That is, when ozone oxidation or ozone accelerated oxidation is performed under alkaline conditions, the ozone concentration in the oxidized water within a few minutes after the oxidation treatment decreases below the lower limit of detection. On the other hand, in neutral to acidity, ozone is often detected even after the reaction. This is because there is a pH dependence on the stability of ozone, especially if the organic component is present in the raw water to be treated, oxidation reaction continues in alkaline. Here, if ozone is not added until the organic component is completely inorganicized, it is possible to create a state in which TOC remains and ozone immediately after the reaction. On the other hand, since the next stage RO membrane is susceptible to oxidative degradation due to ozone, it is necessary to completely decompose residual ozone in the oxidized water to be RO water supply, but residual ozone is present in the ozone oxidized water in which TOC remains. It is not necessary to install a decomposing device of residual ozone.

In addition, even if TOC remains in the oxidized treated water that becomes the RO feed water, as described later, the active site (the boundary between the hydrophobic and hydrophilic parts) showing the surfactant activity is denatured by ozone, thereby reducing membrane fouling. The problem of membrane flux lowering due to the surfactant is solved.

Therefore, in the ozone oxidation step, it is important to adjust the reaction pH so that the pH of the oxidized water is alkaline, and to leave the TOC without completely decomposing the organic components.

In the present invention, the drop in membrane flux due to propagation of microorganisms can be prevented by supplying the alkaline alkaline treated water to the membrane separation step. That is, as will be described later, in the present invention, since the surfactant in the waste water is decomposed by ozone oxidation, its active site is denatured and becomes biodegradable, it contains such a biodegradable component. When the oxidized water is introduced into the membrane separation process, it causes a decrease in the membrane flux due to the propagation of microorganisms, and in order to prevent this, a large amount of slime inhibitor is required to be added. By supplying to the membrane separation step, it is possible to prevent the degradation of the membrane flux caused by such microorganisms. For this reason, it does not cause the problem of a slime disorder, Therefore, it does not require addition of a slime inhibitor, and can reduce a drug cost and can perform a stable process.

In addition to performing such a membrane separation treatment in alkaline conditions, ozone oxidation in alkaline conditions is preferable in that the pH adjustment of the ozonation-treated water may not be necessary. However, in this invention, an alkali chemicals can also be added to ozone oxidation treatment water, and membrane separation process can also be performed.

In the present invention, by the ozone oxidation, the surfactant in the waste water does not need to be decomposed until completely inorganicized, and the surfactant active site of the surfactant may be modified. That is, as described in Non-Patent Document 1, when the surfactant loses the function of the surfactant, membrane fouling is reduced. On the other hand, in ozone oxidation of surfactants, active sites which are likely to be oxidized among surfactants are preferentially oxidized. In the present invention, at least the active site of the surfactant may be oxidized, and a decomposition product of the surfactant modified by ozone oxidation may remain as TOC in the oxidation-treated water. Ozone is almost consumed under ozone oxidation conditions such that some TOC remains, and is also preferable in that ozone can be prevented from entering the membrane separation device.

Therefore, in this invention, it is preferable that the oxidation-treated water discharged | emitted in an oxidation process is pH 9-12, and contains residual TOC (claim 2), and it is especially preferable that the residual TOC concentration is 2-20 mg / L. (Claim 3). However, in order to keep TOC at such a concentration, it is preferable to supply 2-10 weight times of ozone with respect to surfactant in surfactant containing waste water in an oxidation process (claim 5).

Moreover, it is preferable that the membrane separation process in this invention is a RO membrane separation process (claim 4).

In addition, an oxidant removing step of removing oxidant remaining in the water which has been subjected to the oxidizing step may be provided, and water that has undergone the oxidizing agent removing step may be introduced into the membrane separation step (claim 7). A treatment process is preferred (claim 8).

[ To practice the invention  Best form for

EMBODIMENT OF THE INVENTION Hereinafter, with reference to drawings, embodiment of the processing method of surfactant containing wastewater of this invention is described in detail.

1 (a) and (b) are system diagrams showing an embodiment of a method for treating surfactant-containing wastewater of the present invention.

In Fig. 1 (a), oxidizing agents such as hydrogen peroxide (H ₂ O ₂ ) and the like are added to raw water (surfactant-containing drainage), and then the pH of the water in the ozone reaction tower 1 is alkaline, preferably pH. After adding alkali such as sodium hydroxide (NaOH) to 9 to 12, ozone oxidation treatment is carried out in the ozone reaction tower (1), and ozone oxidation treatment water is treated by RO membrane separation treatment in the RO membrane separation apparatus (2). Get the number. (3) is an ozone generator.

Addition of an oxidizing agent such as H ₂ O ₂ to raw water is not necessary. However, by adding an oxidizing agent, the oxidation power of ozone can be used to generate stronger hydroxy radicals, thereby increasing the oxidative decomposition efficiency and further reducing the amount of ozone added. Since it is possible, addition of an oxidizing agent is preferable.

The oxidant to be used is not particularly limited as long as it can generate hydroxy radicals, but H ₂ O ₂ is a preferred oxidant.

The point of addition of the oxidizing agent may be before the raw water comes into contact with ozone or may be after the addition of the alkaline agent.

Further, in the addition amount of the oxidizing agent is not particularly limited, but suitably determined according to the water quality, the type of the oxidizing agent used in the raw water, typically in the range of 0.1 to 1 ratio by weight with respect to the amount of ozone added to the raw water when H ₂ O ₂ il It is preferable to set it as.

In addition, the accelerated oxidation means may apply ultraviolet irradiation in addition to addition of an oxidizing agent such as H ₂ O ₂ .

The ozone reaction tower 1 is not particularly limited as long as it can efficiently absorb ozone into raw water and allow the reaction to proceed while maintaining an alkaline region with high reactivity of ozone or hydroxy radicals. Raw water is sprayed from the spraying plate 1b provided at the top of the tower 1, and ozone transferred from the ozone generator 3 is diffused from the diffuser 1b at the bottom of the tower. It may be an open water tank having a stirrer. It may also be an in-flow ozone supply means such as a line mixer or a vortex pump installed in the pipe. However, it is preferable to provide a reaction tank in order to sufficiently bring ozone into contact with the raw water and to highly oxidize the TOC containing the surfactant in the raw water.

In the present invention, an alkali chemicals are added so that the pH of the water in the ozone reaction tower 1 or the water of the outflow water of the ozone reaction tower 1 is 9-12, especially 10-11. If this adjusted pH is less than 9, the effect of improving ozone oxidative decomposition efficiency cannot be fully obtained by making it alkaline in pH. Under strong alkaline conditions above pH 12, autolysis of ozone is promoted, and undecomposed surfactant remains, which is undesirable.

As the alkali agent for adjusting pH, inorganic alkali agents such as sodium hydroxide (NaOH) and potassium hydroxide (KOH) are used. The alkaline agent may be added to the raw water introduction pipe into the ozone reaction tower 1 or may be added to the ozone reaction tower 1.

However, addition of this alkali agent is not necessarily necessary, and when raw water is a high pH value of about pH 12, it can be used for ozone oxidation as it is, without adjusting pH especially.

There is no restriction | limiting in particular also as an ozone addition method, As shown in FIG. 1, General methods, such as the method of injecting ozone from the ozone generator 3 in the ozone reaction tower 1 in the acid pipe 1b, or injecting into an ejector It can be performed according to. In addition, ozone may be added to ozone water dissolved therein using treated water or the like.

The amount of ozone added varies depending on the quality of the raw water (surfactant concentration), the presence or absence of an oxidizing agent, and the amount of the oxidizing agent. However, the amount of ozone is usually 10 wt% or less, particularly 2-10 wt%, and 6-8 wt. It is preferable.

That is, the reaction between the active site of the surfactant and ozone reacts rapidly with a small amount of ozone because the reaction rate is high. In the case where the surfactant is completely oxidatively decomposed to carbon dioxide gas, the amount of ozone required is preferably about 20 to 50 times the weight of the surfactant. However, in the present invention, the surfactant does not necessarily need to be completely decomposed in the present invention. It is preferable to oxidatively decompose to the extent that the surfactant activity of the surfactant is removed with ozone of about 2 to 10 times the weight of the active agent. However, unlike the surfactant, the modified organic matter (TOC) remaining in the oxidized water has little effect on the flux reduction of the membrane, and is efficiently removed in the membrane separation.

In this way, the degree of TOC remaining during the oxidation treatment by modifying only the active site without completely oxidizing the surfactant is not particularly limited, but is usually about 2 to 20 mg / L. When the residual TOC concentration is too low, the reactivity with ozone tends to be poor, and when too high, the decomposition (modification) of the surfactant may not be sufficient.

However, as for the oxidation-treated water used as RO feed water, pH should be alkaline, and TOC does not necessarily remain. However, the presence of TOC indicates that ozone does not remain and is preferable in view of prevention of oxidative degradation of the film.

In addition, when TOC in oxidized water does not remain and ozone remains, what is necessary is just to remove it in the oxidizing agent removal process mentioned later.

In Fig. 1 (a), the oxidation treatment water of the ozone reaction tower 1 is then subjected to the RO membrane separation treatment in the RO membrane separation apparatus 2.

In the present invention, the RO feed water introduced into the RO membrane separation device 2 is oxidized water having a pH of alkalinity, preferably pH 9-12, particularly preferably pH 10-11. If the pH of this RO water supply is less than 9, the problem of membrane flux reduction by microbial propagation will arise. However, if the pH of the RO feedwater is excessively high, there is a risk of scale failure in the RO membrane separation device depending on the quality of the raw water, and even when the permeated water of the RO membrane separation device 2 is recovered and reused. Even when discharged, it is not preferable to add a large amount of acid to adjust the pH to neutral.

As the RO membrane of the RO membrane separation device 2, a low alkali resistance cellulose acetate RO membrane is not applicable and has alkali resistance, for example, a polyetheramide composite membrane, a polyvinyl alcohol composite membrane, and an aromatic Polyamide membrane etc., Preferably, an aromatic polyamide type composite membrane is mentioned. The RO membrane may be of any type, such as spiral type, hollow fiber type or tubular type.

The permeated water of the RO membrane separation device 2 is discharged out of the system as treated water, and is usually reused in raw water of pure water devices, replenishment water of a cooling tower, and the like.

In FIG. 1 (b), the effluent from the ozone reaction tower 1 is introduced into the activated carbon filter tower 4, and after the remaining ozone and / or oxidizing agents such as H ₂ O ₂ are removed, the RO membrane separation device The point introduced into (2) differs from the method shown in FIG. The treatment conditions in the activated carbon filter tower 4 are appropriately determined according to the residual amount of the oxidizing agent in the effluent of the ozone reaction tower 1. According to this activated carbon treatment, the TOC remaining in the ozonation-treated water can be further removed.

As shown in Fig. 1 (a) and (b), the raw water containing the surfactant is subjected to ozone oxidation treatment, and then activated carbon treatment is introduced into the RO membrane separation apparatus 2 as necessary, whereby the RO membrane separation apparatus 2 It is possible to obtain a high quality treated water from which TOC is highly removed by performing a stable treatment for a long time without causing a decrease in the flux at).

1 shows an example of the embodiment of the present invention, and the present invention is not limited to any illustration without departing from the gist of the present invention. For example, when the pH of the oxidized water or activated carbon treated water introduced into the RO membrane separation device is not sufficiently alkaline, the pH is adjusted by further adding an alkali agent to the oxidized treated water or activated carbon treated water to be RO feed water. RO membrane separation treatment may be performed. In addition, when raw water contains hardness components, such as calcium ion and magnesium ion, a scale inhibitor can also be added to this RO feed water in order to prevent the scale disorder by concentration.

In this case, as the scale inhibitor to be added to the RO feed water, chelate scale control papers such as ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA), which easily dissociate in the alkali region and form complexes with metal ions, are preferably used. , Other (meth) acrylic acid polymers and salts thereof, low molecular weight polymers such as maleic acid polymers and salts thereof, ethylenediaminetetramethylenephosphonic acid and salts thereof, hydroxyethylidenediphosphonic acid and salts thereof, nitrilotrimethylenephosphonic acid And phosphonic acids and phosphonic acid salts such as salts thereof, phosphonobutanetricarboxylic acid and salts thereof, hexametaphosphate and salts thereof, tripolyphosphoric acid and salts thereof, and the like.

The membrane separation treatment after the oxidation treatment is not limited to the RO membrane separation treatment but may be a nanofilter (NF) membrane separation treatment. However, in view of the removal of the TOC, RO membrane separation treatment is preferable.

The raw water treated in the present invention is a wastewater containing a surfactant, but the surfactant concentration is usually about 0.2 to 10 mg / L, and in the present invention, the surfactant concentration is 0.1 to 1 mg by oxidizing such a surfactant-containing wastewater. / L, TOC It is preferable to obtain an oxidation treated water of about 5 to 15 mg / L, and to treat this by RO membrane separation to obtain a treated water of about TOC 0.5 to 1 mg / L.

EXAMPLE

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1

The wash water (TOC = 11 mg / L, nonionic surfactant 2 mg / L) of a liquid crystal manufacturing process was made into raw water, NaOH was added to this, and it adjusted to pH 10.5. Ozone gas was blown into this, and 50 mg / L equivalent ozone was dissolved. The obtained ozonated oxidation water had a pH of 9.6, an electrical conductivity of 190 mS / m, a TOC of 8 mg / L, a nonionic surfactant of 0.5 mg / L or less, and a residual ozone of 0.5 mg / L or less.

This oxidation treated water was passed through the RO membrane separation device. An aromatic polyamide-based composite membrane was used as the RO membrane, and was operated at a transmembrane pressure of about 1.2 MPa and a recovery rate of 75%.

As a result, the treatment was continued by maintaining the permeate (flux) 0.6 m 3 / m 2 / d for 2 weeks, the water quality of the RO membrane separation device was pH 9.8, conductivity 1.2 mS / m, TOC = 0.8 mg / It was L.

Example 2

10 mg / L of hydrogen peroxide was added to the wash water of the liquid crystal manufacturing process made into raw water in Example 1, and it adjusted to pH 10.5 by adding NaOH. Ozone gas was blown into this, and ozone equivalent to 40 mg / L was dissolved. The obtained ozonated water was pH 9.4, electrical conductivity 18 mS / m, TOC = 9 mg / L, nonionic surfactant = 0.5 mg / L or less, residual ozone = 0.5 mg / L, hydrogen peroxide = 5 mg / L or less .

This oxidized water was passed through an activated carbon filter at a water passage rate of SV 10 ^{hr −1} , and then passed through the RO membrane separation device under the same conditions as in Example 1.

As a result, the treatment was continued by maintaining the permeate amount (flux) 0.7 m 3 / m 2 / d for 2 weeks, and the water quality of the permeate was pH 9.5, electric conductivity 1.0 mS / m, TOC = 0.6 mg / L.

Comparative example  One

After adding hydrochloric acid to the ozone oxidation-treated water obtained by carrying out similarly to Example 1, adjusting to pH 6.5, after adding 10 mg / L of "Chloramine T" by Kishida Kagaku Co., Ltd. as a combined chlorine-type slime inhibitor, As a result of passing through the RO membrane separation apparatus under the same conditions, the amount of permeate (flux) gradually decreased to 0.3 m 3 / m 2 / d after one week. The water quality of the permeate was pH 6.3, electrical conductivity 0.3 mS / m, and TOC = 0.2 mg / L.

From the above results, according to the present invention, in the case of RO membrane separation treatment after oxidizing the surfactant-containing wastewater with ozone, RO membrane contamination by the surfactant can be prevented to keep the membrane plus high so that stable treatment can be continued. It can be seen that.

Claims (8)

In the method of sequentially treating the surfactant-containing waste water in the oxidation step and the membrane separation step, The oxidation step is a step of oxidizing the surfactant in the waste water by contacting the waste water with ozone under alkaline conditions, And the membrane separation step is a step of membrane separation of alkaline oxidized water discharged from the oxidation step. The method of claim 1, The oxidation treatment water discharged from the said oxidation process is pH 9-12, and contains residual TOC, The treatment method of the waste water containing surfactant characterized by the above-mentioned. The method of claim 2, The residual TOC concentration in the said oxidized water is 2-20 mg / L The treatment method of surfactant containing wastewater characterized by the above-mentioned. The method according to any one of claims 1 to 3, The membrane separation process is a reverse osmosis membrane separation process, characterized in that the surfactant-containing wastewater treatment method. The method according to any one of claims 1 to 3, In the oxidation step, 2 to 10 times the amount of ozone is supplied to the waste water relative to the surfactant in the surfactant-containing waste water. The method according to any one of claims 1 to 3, The said oxidation process is the accelerated oxidation process by combined use of ozone and hydrogen peroxide, The surfactant containing wastewater processing method characterized by the above-mentioned. The method according to any one of claims 1 to 3, And an oxidant removal step of removing the oxidant remaining in the water that has undergone the oxidation step, wherein the water that has passed the oxidant removal step is introduced into the membrane separation step. The method of claim 7, wherein The method of treating surfactant-containing waste water, wherein the oxidant removing step is an activated carbon treatment step.

Images