JP2013252478A - Treatment method and treatment device of oil component-containing drainage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel treatment method and a treatment device which can selectively and efficiently separate and collect an oil component from oil component-containing drainage.SOLUTION: There is provided a treatment method of oil-containing drainage which is characterized in that: drainage (hereinafter referred to as [oil-containing drainage]) containing oil as water to be treated (raw water) is supplied to a cross-flow type hydrophilic film filter using a hydrophilic film; hydrophilic film filtered water and the oil-containing water are separated from each other by hydrophilic film filtering; the hydrophilic film filtered water is collected; on the other hand, the oil-containing water is further supplied to cross-flow type hydrophobic filter using a hydrophobic film; an oil component and oil component removed water are separated from each other by hydrophobic filtering; the oil component is collected; on the other hand, the hydrophobic film filtered water is added to the water to be treated (raw water), supplied to the cross-flow type hydrophilic film filter, and subjected to circulation treatment.

Description

  The present invention is a wastewater containing oil generated during production or production of oil, coal, natural gas, shale gas, cold bed methane (CBM), oil sand, surreal oil, etc. (referred to as “oil-containing wastewater”). The present invention also relates to a processing method and a processing apparatus for oil-containing wastewater discharged from various factories, for example, oil-containing wastewater discharged from a petrochemical factory.

  Oil-containing wastewater generated during production or production of oil, coal, natural gas, shale gas, cold bed methane (CBM), oil sands, surreal oil, etc., and oil-containing wastewater discharged from, for example, petrochemical plants Therefore, there is a need for a method for selectively and efficiently separating oil from such oil-containing wastewater.

  As a method for selectively removing oil from oil-containing wastewater, that is, an oil-water separation method, for example, a method using a difference in specific gravity between oil and water, a method using chemicals, a method by membrane filtration, etc. are known. Among them, a method using membrane filtration has attracted attention as a technique capable of treating a large amount of oil-containing wastewater.

  With regard to the oil-water separation method by membrane filtration, for example, Patent Document 1 discloses an oil-water separation method in which water-containing oil is passed through the hollow portion of a hydrophobic porous tube and oil is removed from the outer wall portion of the hollow fiber. Has been.

  Patent Document 2 discloses an oil-containing wastewater treatment method that uses a ceramic asymmetric membrane module and performs cross-flow filtration.

  In Patent Document 3, when water-containing oil is passed through a hollow fiber membrane module provided with a hydrophobic porous hollow fiber membrane to perform oil-water separation, the oil-containing water is passed through the outer surface of the hydrophobic porous hollow fiber membrane. The gist of the oil-water separation method is characterized in that the oil component in the water-containing oil is selectively permeated through the membrane surface. When oil-water separation is performed by cross-flow filtration that circulates and returns a portion of the hydrous oil, the membrane surface is washed by the hydrous oil flowing on the outer wall surface of the hydrophobic porous hollow fiber membrane, further clogging the membrane wall surface. It is difficult to generate oil and water separation can be performed with a high filtration amount.

  In Patent Document 4, when processing an oil-in-water emulsion by cross-flow filtration, a hollow fiber membrane module provided with a porous hollow fiber membrane is used to remove the oil-in-water emulsion from the hollow fiber membrane. The water is passed through the wall surface, allowing the water in the oil-in-water emulsion to selectively permeate to the inner wall surface of the hollow fiber membrane. When the filtration flow rate decreases, the permeated water is reversed from the inner wall surface to the outer wall surface of the hollow fiber membrane. A method for treating an oil-in-water emulsion, characterized by passing in a direction, is disclosed.

JP-A-52-35368 Japanese Patent Laid-Open No. 1-130780 JP-A-10-296003 Japanese Patent Laid-Open No. 11-138163

In the actual treatment of oil-containing wastewater, membrane filtration using a hydrophobic membrane is often employed in order to avoid clogging due to oil. However, in the case of oil-containing wastewater that is generated with the production or production of oil and natural gas, the main component is water even if there is a lot of oil. Since the wastewater hardly permeates the membrane, it has a problem that it is difficult to efficiently treat a large amount of water to be treated.
On the other hand, if such oil-containing wastewater is treated by membrane filtration using a hydrophilic membrane, the oil-containing wastewater separated and recovered will contain a large amount of water, so that the oil can be selectively separated and recovered. I had a problem.

  Accordingly, the present invention relates to a method for selectively separating oil from oil-containing wastewater generated during production or production of oil, natural gas, etc., and a new method capable of selectively and efficiently separating and recovering oil. We propose a method for treating oil-containing wastewater and a treatment apparatus therefor.

  The present invention supplies wastewater containing oil as treated water (raw water) (referred to as “oil-containing wastewater”) to a membrane filtration device having a hydrophilic membrane and a hydrophobic membrane. The present invention proposes a method for treating oily water-containing wastewater, characterized in that oil can be simultaneously recovered from a hydrophobic membrane. At this time, the liquid that has passed through the hydrophilic membrane or the hydrophobic membrane is circulated to the inlet of the membrane filtration device, so that water can be recovered from the hydrophilic membrane and oil can be recovered from the hydrophobic membrane simultaneously by the cross-flow method. It is preferable to do so.

  The present invention is also an oil-containing wastewater treatment device for treating oil-containing wastewater, a membrane filtration device provided with a hydrophilic membrane and a hydrophobic membrane, recovery means for recovering water from the hydrophilic membrane, An oil / water-containing wastewater treatment apparatus including a recovery means for recovering oil from a hydrophobic membrane is proposed. At this time, it is preferable to provide a circulation means for circulating the liquid that has passed through the hydrophilic membrane or the hydrophobic membrane to the inlet of the membrane filtration device.

  According to the method and apparatus for treating oil-containing wastewater proposed by the present invention, oil can be selectively and efficiently separated and recovered from oil-containing wastewater generated during production or production of oil or natural gas. At the same time, treated water from which oil has been removed from the oil-containing wastewater can be separated and recovered.

It is the figure which showed an example of the processing method and processing apparatus of the oil containing waste water which concern on this invention. It is the figure which showed the other example of the processing method and processing apparatus of the oil content containing waste water which concern on this invention. It is the figure which showed an example of the processing method and processing apparatus of the oil containing waste water which concern on this invention. It is the figure which showed an example of the filtration apparatus in the processing apparatus of the oil-containing waste water shown in FIG. It is the figure which showed the example using a hydrocyclone as another example of the processing apparatus of the oil-containing waste water which concerns on this invention. It is the figure which showed the example using the film | membrane formed by combining a hydrophobic film | membrane and a hydrophilic film | membrane as another example of the processing apparatus of the oil-containing waste water which concerns on this invention. It is sectional drawing which showed an example of the structure of the composite film formed by combining a hydrophobic membrane and a hydrophilic membrane. It is the figure which showed the further another example of the processing apparatus of the oil-containing waste water which concerns on this invention.

  Next, the present invention will be described based on exemplary embodiments, but the present invention is not limited to the embodiments described below.

<First Embodiment>
An oil-containing wastewater treatment method according to an example of an embodiment of the present invention (referred to as “the present treatment method 1”), as shown in FIG. 1, is a wastewater containing oil as treated water (raw water) (“oil Is supplied to a cross-flow type hydrophilic membrane filtration device 2 using a hydrophilic membrane, and is separated into hydrophilic membrane filtered water and oil-containing water by hydrophilic membrane filtration. While the membrane filtrate is recovered, the oil-containing water is further supplied to a cross-flow type hydrophobic membrane filtration device 3 using a hydrophobic membrane, and oil and oil-removed water are obtained by cross-flow type hydrophobic membrane filtration. Separating and recovering the oil, while adding the oil-removed water to the water to be treated (raw water), supplying the water again to a cross-flow type hydrophilic membrane filtration device, and containing the oil This is a wastewater treatment method.

In the method and apparatus for treating oil-containing wastewater proposed by the present invention, oil-containing wastewater as treated water (raw water) is supplied to a cross-flow type hydrophilic membrane filtration device. Oil-containing wastewater as treated water (raw water) has a high moisture ratio and low oil content, so it is efficient for hydrophilic membrane filtered water and oil-containing water from which oil has been removed by a cross-flow type hydrophilic membrane filtration device. It can be separated well.
Next, the oil-containing water is supplied to a cross-flow type hydrophobic membrane filtration device. Since the oil-containing water has a higher oil concentration than the raw water, the oil can be selectively and efficiently separated and recovered by cross-flow hydrophobic membrane filtration. Furthermore, oil-removed water is added to the water to be treated (raw water) and the process is circulated to select treated water from which oil has been removed (that is, hydrophilic membrane filtered water) and oil with less water. Can be recovered efficiently and efficiently.

As an apparatus for carrying out this treatment method 1, for example, as shown in FIG. 1, treated water for storing wastewater containing oil as treated water (raw water) (referred to as "oil-containing wastewater") Storage tank 1, cross-flow type hydrophilic membrane filtration device 2 using a hydrophilic membrane, cross-flow type hydrophobic membrane filtration device 3 using a hydrophobic membrane, and raw water into treated water storage tank 1 A raw water supply pipe 4 to be supplied, a pipe 5 for supplying oil-containing wastewater in the treated water storage tank 1 to the hydrophilic membrane filtration device 2, a circulation pump 6 disposed in an intermediate portion of the pipe 5, and a hydrophilic property The treated water discharge pipe 7 that discharges the hydrophilic membrane filtrate separated by the membrane filtration device 2 to the outside of the circulation system, and the oil-containing water separated by the hydrophilic membrane filtration device 2 is supplied to the hydrophobic membrane filtration device 3. Oil drainage that drains the oil separated by piping 8 and hydrophobic membrane filtration device 3 out of the circulation system 9, may be mentioned oil-free water separated by a hydrophobic membrane filtration unit 3 and a return pipe 10 for supplying the treated water storage tank 1, the processing unit of the oil-containing wastewater as an example. However, the present invention is not intended to be limited to such a processing apparatus. For example, the treated water storage tank 1 may be omitted, and the oil removal water separated by the hydrophobic membrane filtration device 3 may be supplied to the hydrophilic membrane filtration device 2, or other configurations may be adopted. it can.
Hereinafter, the configuration of the processing apparatus will be described in detail.

(Treatment water storage tank 1)
The treated water storage tank 1 is a water tank that mixes and stores treated water. The treated water storage tank 1 is connected to the raw water supply pipe 4 and the return pipe 10 on the inlet side, and on the outlet side. Pipe 5 is connected.
The to-be-treated water storage tank 1 may be provided with a stirring means.

(Hydrophilic membrane filtration device 2)
The hydrophilic membrane filtration device 2 may be a cross-flow type hydrophilic membrane filtration device using a hydrophilic membrane.

A hydrophilic membrane means a membrane with a surface tension that is closer to the surface tension of water (about 70 mN / m) than the surface tension of oil (about 25 mN / m).
Examples of the hydrophilic film include a ceramic film and a hydrophilic organic film.
Examples of the ceramic film include a film made of aluminum oxide (alumina) or zirconium oxide.
As the hydrophilic organic film, for example, a film made of a resin having a hydrophilic property such as polyvinyl alcohol, cellulose acetate, polyamide, polyacrylonitrile, or the surface of a hydrophobic organic film is modified so as to increase the hydrophilicity. Examples thereof include a hydrophilized membrane obtained by introducing a hydrophilic group such as a sulfone group or a carbonyl group into a membrane, or a hydrophobic membrane.
In the case of a hollow fiber, a hydrophobic porous hollow fiber membrane obtained by forming these materials by a melt drawing method, a wet method, or the like can be used.

  The cross flow type means to counter the total amount filtration type, and the cross flow type membrane filtration device is a membrane filtration device of a type in which water to be treated flows parallel to the membrane surface.

  As the cross-flow filtration type hydrophilic membrane filtration device 2, for example, oil-containing wastewater (treated water) is fed in parallel along the outer wall surface of the hydrophilic membrane, and moisture is selected by hydrophilic interaction. In particular, the moisture permeated from the outer wall surface side to the inner wall surface side of the hydrophilic membrane and permeated through the membrane surface is discharged out of the circulation system as the hydrophilic membrane filtered water through the treated water discharge pipe 7, while not permeating the membrane surface. The components can be configured to be supplied to the hydrophobic membrane filtration device 3 as oil-containing water through the pipe 8.

  Thus, in the cross-flow filtration method, raw water is supplied to one membrane surface (raw water supply side separation membrane surface) of the separation membrane, and the permeated water that has permeated the separation membrane is used as the other membrane surface (permeation side separation membrane). Since the raw water flows in parallel to the separation membrane surface of the raw water supply side and is filtered, the oil component adhering to the separation membrane surface can be peeled off from the membrane surface, allowing stable operation over a long period of time. It can be performed. Further, in the cross-flow filtration method, the clogging of the membrane surface decreases as the flow velocity of the water to be treated flowing on the outer wall surface side increases, so that oil / water separation can be performed while maintaining a high filtration flow rate for a long time.

  In addition, the specific structure in the hydrophilic membrane filtration apparatus 2 is arbitrary. For example, it is possible to employ a porous hollow fiber membrane module in which a U-shaped hydrophilic porous hollow fiber membrane is fixed in a housing and arranged to open at the outlet. However, it is not limited to such a structure.

  It is also possible to provide backwashing means in the hydrophilic membrane filtration device 2. For example, the hydrophilic membrane can be washed by reversely passing a part of the hydrophilic membrane filtered water through the hydrophilic membrane filtration device 2.

(Hydrophobic membrane filtration device 3)
The hydrophobic membrane filtration device 3 may be a cross-flow type hydrophobic membrane filtration device using a hydrophobic membrane.

A hydrophobic membrane means a membrane with a surface tension that is closer to the surface tension of oil (about 25 mN / m) than the surface tension of water (about 70 mN / m).
Examples of the hydrophobic membrane include membranes made of materials such as polyolefins such as polyethylene and polypropylene, polysulfone, polyamide, polyimide, polytetrafluoroethylene, and polyvinylidene fluoride.
In the case of a hollow fiber, a hydrophobic porous hollow fiber membrane obtained by forming these materials by a melt drawing method, a wet method, or the like can be used.
However, in the hydrophobic film, it is sufficient that at least the liquid contact part of the film has hydrophobicity, and it is not necessary that all parts of the material have hydrophobicity. For example, even when a film is formed from a non-hydrophobic material, it can be used as a hydrophobic film if the wetted part of the film is hydrophobic coated.

  As with the hydrophilic membrane filtration device 2, the hydrophobic membrane filtration device 3 preferably employs a cross-flow membrane filtration device.

  Specifically, oil-containing water (treated water) is fed in parallel along the outer wall surface side of the hydrophobic membrane, and the oil content is selectively transferred from the outer wall surface side of the hydrophobic membrane by hydrophobic interaction. Oil that has permeated the wall surface and permeated through the membrane surface is discharged out of the circulation system through the oil discharge pipe 9, while components that do not permeate through the membrane surface are returned to the treated water storage tank 1 through the return pipe 10 as oil removal water. What is necessary is just to make it supply.

  In this way, in the hydrophobic membrane filtration device 3 of the cross flow filtration system, oil-containing water is supplied to one membrane surface of the separation membrane, and the oil that has permeated the separation membrane is removed from the other membrane surface of the separation membrane (permeation side separation membrane). In order to separate the oil by flowing oil-containing water parallel to the oil-containing water supply side separation membrane surface, the solid content other than the oil adhering to the separation membrane surface is peeled off from the membrane surface. Can be operated stably over a long period of time. Also, in the cross-flow filtration method, the higher the membrane surface flow rate of the water to be treated flowing on the outer wall surface side, the less clogging of the membrane surface, so that oil-water separation can be performed while maintaining a high filtration flow rate for a long time. Become.

  However, the specific structure of the hydrophobic membrane filtration device 3 is arbitrary. For example, it is also possible to employ a porous hollow fiber membrane module in which a U-shaped hydrophobic porous hollow fiber membrane is fixed in a housing and arranged to open at the outlet.

  It is also possible to provide backwashing means in the hydrophobic membrane filtration device 3. For example, the hydrophobic membrane can be washed by reversely passing a part of the separated oil through the hydrophobic membrane filtration device 3.

(Circulating pump 6)
By driving the circulation pump 6, oil-containing wastewater as treated water in the treated water storage tank 1 can be sent to the hydrophilic membrane filtration device 2 via the pipe 5.
The pump 6 can be used without particular limitation as long as it can send liquid at a necessary flow rate, and examples thereof include a trochoid pump and a vane pump.

<Second Embodiment>
The method for treating oil-containing wastewater according to another example of the embodiment of the present invention (referred to as “the present treatment method 2”) includes hydrophilic membrane filtration by the hydrophilic membrane filtration device 2 in the present treatment method 1 and hydrophobicity. This is a processing method in which the order of the hydrophobic membrane filtration by the membrane filtration device 3 is reversed.
That is, in this treatment method 2, as shown in FIG. 2, oil-containing wastewater as treated water (raw water) is supplied to a cross-flow type hydrophobic membrane filtration device 3 using a hydrophobic membrane, Oil separation and oil removal water are separated by membrane filtration, and the oil is recovered, while the oil removal water is supplied to a cross-flow type hydrophilic membrane filtration device 2 using a hydrophilic membrane, and hydrophilic membrane filtration. Is separated into hydrophilic membrane filtered water and oil-containing water, and the hydrophilic membrane filtered water is recovered, while the water to be treated (raw water) is added to the oil-containing water, and the cross-flow type hydrophobic membrane is again formed. It is the processing method of the oil containing waste water characterized by supplying to the filtration apparatus 3 and carrying out the circulation process.

  As an apparatus for carrying out this treatment method 2, for example, as shown in FIG. 2, a treated water storage tank 1 for storing oil-containing wastewater as treated water (raw water) and a cloth using a hydrophobic membrane Flow-type hydrophobic membrane filtration device 3, cross-flow-type hydrophilic membrane filtration device 2 using a hydrophilic membrane, raw water supply pipe 4 for supplying raw water to the treated water storage tank 1, and treated water storage A piping 21 for supplying the oil-containing wastewater in the tank 1 to the hydrophobic membrane filtration device 3, a circulation pump 6 disposed in an intermediate portion of the piping 21, and an oil component separated by the hydrophobic membrane filtration device 3 as a circulation system An oil discharge pipe 9 for discharging to the outside, a pipe 22 for supplying oil-removed water separated by the hydrophobic membrane filtration device 3 to the hydrophilic membrane filtration device 2, and a hydrophilic membrane separated by the hydrophilic membrane filtration device 2 Treated water discharge pipe 7 for discharging filtrate water out of the circulation system, and hydrophilic membrane filtration device 2 Can be exemplified separated oil-containing water and a return pipe 23 for supplying the treated water storage tank 1, the processing unit of the oil-containing wastewater as an example. However, the present invention is not intended to be limited to such a processing apparatus. For example, the treated water storage tank 1 may be omitted, and the oil-containing water separated by the hydrophilic membrane filtration device 2 may be supplied to the hydrophobic membrane filtration device 3, or other configurations may be adopted. it can.

  In addition, in the present treatment methods 1 and 2, since the oil concentration in the oil-containing wastewater as raw water fluctuates, it is necessary to perform control and operation for stabilizing the recovered amount of oil and the recovered amount of water (treated water). preferable. Specifically, for example, a suction pump or the like is provided on the suction side of the hydrophilic membrane filtration device 2 and / or the hydrophobic membrane filtration device 3, and the suction pump is controlled according to the oil concentration in the circulation line and / or the storage tank. Thus, the recovered amount of oil and the recovered amount of water (treated water) can be stabilized.

<Third Embodiment>
As another example of the treatment apparatus for oil-containing wastewater, the pipe 5, the circulation pump 6, the hydrophilic membrane filtration device 2, the pipe 8, the hydrophobic membrane filtration device 3, and the return pipe 10 are provided. An oil-containing wastewater treatment apparatus having a configuration that is arranged in the same hermetic system can be mentioned.
In this case, the arrangement in the same airtight system means that the air is connected so as not to leak. Specifically, by driving the circulation pump 6, This means that the oil-containing waste water can be returned to the treated water storage tank 1 through the pipe 5, the hydrophilic membrane filtration device 2, the pipe 8, the hydrophobic membrane filtration device 3, and the return pipe 10. To do.

  For example, as shown in FIGS. 3 and 4, a treated water storage tank 1 for storing wastewater containing oil as treated water (raw water) (referred to as “oil-containing wastewater”), and a hydrophilic membrane filtration chamber. 12, a filtration device 11 having a hydrophobic membrane filtration chamber 13, a raw water supply pipe 4 for supplying raw water to the treated water storage tank 1, and an oil-containing wastewater in the treated water storage tank 1 are supplied to the filtration device 11. Piping 5, a circulation pump 6 disposed in an intermediate portion of the piping 5, a treated water discharge pipe 7 for discharging the hydrophilic membrane filtrate separated by the filtration device 11, and a filtration device 11. An oil content discharge pipe 9 for discharging the separated oil content to the outside of the circulation system and a return pipe 10 for supplying the oil content removed water separated by the filtration device 11 to the treated water storage tank 1 are configured. be able to.

  At this time, the filtration device 11 includes a hydrophilic membrane filtration chamber 12 provided with a hydrophilic membrane 12a, and a hydrophobic membrane filtration chamber 13 provided with a hydrophobic membrane 13a, and the hydrophilic membrane filtration chamber 12 and the hydrophobic membrane. The filtration chamber 13 is connected by a pipe 8, the treated water discharge pipe 7 is connected to the hydrophilic membrane filtrate outlet side of the hydrophobic membrane filtration chamber 13, and the oil component is discharged to the oil outlet side of the hydrophobic membrane filtration chamber 13. An apparatus in which the pipe 9 is connected, the return pipe 10 is connected to the outlet side of the oil-removed water in the hydrophobic membrane filtration chamber 13, and the entire filtration device 11 is hermetically formed can be mentioned.

  The hydrophilic membrane filtration chamber 12 has a plurality of hydrophilic membranes 12a arranged at appropriate intervals in an airtight chamber, and distributes oil-containing waste water in parallel with the membrane surface of the hydrophilic membrane 12a. The permeated hydrophilic membrane filtered water is discharged out of the system through the treated water discharge pipe 7, while the oil-containing water that does not permeate the hydrophilic membrane 12 a is supplied to the hydrophobic membrane filtration chamber 13 through the pipe 8. it can.

  In the hydrophobic membrane filtration chamber 13, a plurality of hydrophobic membranes 13a are arranged in the airtight chamber at appropriate intervals, and the oil-containing water is circulated in parallel with the membrane surface of the hydrophobic membrane 13a. The oil that has permeated the inside can be discharged out of the system through the oil discharge pipe 9, while oil-removed water that does not pass through the hydrophobic membrane 13 a can be supplied to the treated water storage tank 1 through the return pipe 10. .

<Other embodiments>
Supply oil-containing wastewater as treated water (raw water) to a membrane filtration device equipped with a hydrophilic membrane and a hydrophobic membrane so that water can be recovered from the hydrophilic membrane and oil from the hydrophobic membrane at the same time. To do this, for example, a membrane filtration device provided with an integrated hydrophilic membrane and hydrophobic membrane, a recovery means for recovering water from the hydrophilic membrane, a recovery means for recovering oil from the hydrophobic membrane, It is also possible to implement by the processing apparatus of the oil-water containing waste water provided with.

For example, as shown in FIG. 5, by using a hydrocyclone, a hydrophilic film is attached to the outside, and a hydrophobic film is placed on the central axis. On the other hand, the oily liquid is close to the hydrophobic membrane, so that it can be compactly and efficiently separated.
Thus, there is a possibility that the pump power can be reduced by using the centrifugal force.

  In addition, as shown in FIG. 6, as a parallel partition plate or inclined plate, a large number of flat membrane-like composite films formed by combining a hydrophobic film and a hydrophilic film are arranged in parallel at regular intervals, By supplying fine bubbles of air or inert gas together with the water to be treated at these inlets, water and oil can be recovered simultaneously while separating the oil and water.

  At this time, the composite membrane formed by combining the hydrophobic membrane and the hydrophilic membrane is bonded to the upper side of the partition plate while the hydrophobic membrane is attached to the lower side of the partition plate, for example, as shown in FIG. It is affixed with an adhesive film and aerated with air or inert gas so that water containing a large amount of oil is in contact with the hydrophobic film and water having a small amount of oil is in contact with the hydrophilic film. Is preferred.

  Furthermore, as shown in FIG. 8, a centrifugal coalescer (pump) is placed in the previous stage, and water and oil are simultaneously recovered by passing the central axis side liquid at the outlet through a hydrophobic membrane and the outside through a hydrophilic membrane. You can also.

DESCRIPTION OF SYMBOLS 1 Treated water storage tank 2 Hydrophilic membrane filtration apparatus 3 Hydrophobic membrane filtration apparatus 4 Raw water supply pipe 5 Piping 6 Circulation pump 7 Treated water discharge pipe 8 Piping 9 Oil discharge pipe 10 Return pipe 11 Filtration apparatus 12 Hydrophilic membrane filtration chamber 12a Hydrophilic membrane 13 Hydrophobic membrane filtration chamber 13a Hydrophobic membrane 21 Pipe 22 Pipe 23 Return pipe

Claims (10)

  Wastewater containing oil as the water to be treated (raw water) (referred to as “oil-containing wastewater”) is supplied to a membrane filtration device equipped with a hydrophilic membrane and a hydrophobic membrane, and water from the hydrophilic membrane is hydrophobic. A method for treating drainage containing oil and water, wherein oil can be recovered simultaneously from the conductive membrane.   The liquid that passed through the hydrophilic membrane or hydrophobic membrane was circulated to the inlet of the membrane filtration device so that water could be recovered from the hydrophilic membrane and oil from the hydrophobic membrane at the same time by the crossflow method. The method for treating oil-water-containing wastewater according to claim 1.   An oil-containing wastewater treatment device for treating oil-containing wastewater, comprising a membrane filtration device provided with a hydrophilic membrane and a hydrophobic membrane, recovery means for recovering water from the hydrophilic membrane, and oil content from the hydrophobic membrane An oil / water-containing wastewater treatment apparatus comprising: a collecting means for collecting the oil.   The processing apparatus of the oil-water containing waste_water | drain of Claim 3 provided with the circulation means to circulate the liquid which passed the said hydrophilic membrane or the hydrophobic membrane to the inlet_port | entrance of the said membrane filtration apparatus.   Oil-containing wastewater as raw water to be treated (raw water) is supplied to a cross-flow type hydrophilic membrane filtration device using a hydrophilic membrane and separated into hydrophilic membrane filtered water and oil-containing water by hydrophilic membrane filtration. The hydrophilic membrane filtered water is recovered while the oil-containing water is further supplied to a cross-flow type hydrophobic membrane filtration device using a hydrophobic membrane, and the oil and oil-removed water are obtained by hydrophobic membrane filtration. Separating and recovering the oil, adding the treated water (raw water) to the oil-removed water, supplying the water to the cross-flow type hydrophilic membrane filtration device, and circulating the oil Wastewater treatment method.   Oil-containing wastewater as raw water to be treated (raw water) is supplied to a cross-flow type hydrophobic membrane filtration device using a hydrophobic membrane and separated into oil and oil-removed water by hydrophobic membrane filtration. On the other hand, the oil-removed water is supplied to a cross-flow type hydrophilic membrane filtration apparatus using a hydrophilic membrane, and separated into hydrophilic membrane filtered water and oil-containing water by hydrophilic membrane filtration. Oil-containing wastewater, characterized in that the treated water (raw water) is added to the oil-containing water while the membrane-filtered water is recovered and supplied to the cross-flow type hydrophobic membrane filtration device for circulation treatment Processing method.   A cross-flow type hydrophilic membrane filtration device using a hydrophilic membrane, a cross-flow type hydrophobic membrane filtration device using a hydrophobic membrane, and oil-containing water discharged from the hydrophilic membrane filtration device An oil-containing wastewater treatment apparatus comprising: a pipe for supplying to the permeable membrane filtration apparatus; and a pipe for supplying oil-removed water discharged from the hydrophobic membrane filtration apparatus to the hydrophilic membrane filtration apparatus.   The processing apparatus of the oil containing waste water of Claim 7 provided with the structure which arrange | positions a circulation pump in the near side of the said hydrophilic membrane filtration apparatus or the said hydrophobic membrane filtration apparatus.   The hydrophilic membrane filtration device, the hydrophobic membrane filtration device, a pipe for supplying the oil-containing water to the hydrophobic membrane filtration device, and a pipe for supplying the oil removal water to the hydrophilic membrane filtration device, The processing apparatus of the oil containing waste water of Claim 8 provided with the structure formed by arrange | positioning the said circulation pump in the same airtight system.   The processing apparatus of the oil containing waste water in any one of Claims 7-9 provided with the suction pump in the suction side (front side) of a hydrophilic membrane filtration apparatus and / or a hydrophobic membrane filtration apparatus.

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