JPH10146588A - Apparatus and method for water treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To treat water to be treated stably for a long term of time by a method wherein in an oil drop separation means, electric power is supplied to an electrode composed of an amphoteric metal as an anode, water to be treated containing a micro oil drop is treated, the water to be treated after treatment is introduced into a three-dimensional fixed bed type electrolyzer, and electric power of which polarity is converted is supplied to a fixed bed type electrode to carry out germicidal treatment. SOLUTION: An oil drop which is separated by introducing water to be treated from an inlet 10 for water to be treated into a treatment tank 1 of an oil drop separation means, is exhausted from an outlet of flock foams, and treated water is exhausted from a treated water outlet 2. The treated water from which an oil content is separated passes through filter equipment 35 connected to a water duct, solid is removed, and the treated water is introduced into a three-dimensional fixed bed type double electrodes system electrolyzer 36. The treated water which is germicidally treated in the three-dimensional fixed bed type double electrodes system electrolyzer 36 is used again as the treated water from an outlet. Further, a power source supplying electric power to the oil drop separation means and a power source supplying electric power to the three-dimensional fixed bed type double electrodes system electrolyzer 36 have a common power source 38. Respective power supply terminals 7, 8 are connected in parallel to the terminals 24, 24'.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a water treatment apparatus and a water treatment method for electrochemically treating water to be treated containing micro oil droplets and microorganisms.

[0002]

2. Description of the Related Art In recent years, the reuse of industrial water has become popular,
BACKGROUND ART Various impurities contained in industrial water used once have been separated and then reused. In general, the impurities contained in each industrial water are often separated by squeezing a target for each, since the components are known.

[0003] For example, processing water used in food processing is
Since it is rich in nutrients, microorganisms such as bacteria proliferate, and it is impossible to reuse it as processing water for food processing without treatment. It is impossible to treat these microorganisms such as bacteria with a fungicide or fungicide because the used fungicide or fungicide may be mixed into food. Therefore, it has been desired to easily process such processing water and reuse it as sterile water.

[0004] As a water treatment method which does not have the above-mentioned disadvantages, for example, Japanese Patent Application Laid-Open Nos. 3-224686 and 4-274.
No. 88, etc., there is a method of electrochemical treatment. According to this method, a large amount of water can be efficiently treated without using a special chemical or the like.

However, the processing water used in food processing is
Once used, the oil eluted from the food becomes minute oil droplets and is mixed into the processing water. In the above-described method, if the water to be treated containing minute oil droplets is treated as it is, the electrode is clogged, or the surface of the electrode is masked with oil, so that sterilization cannot be performed in a short time. Furthermore, these minute oil droplets have a strong adverse effect such as being a nutrient source of microorganisms and bacteria existing in the processing water and adhering to the processed food, lowering the commercial value of the food. In particular, washing water such as broiler and tofu has a low cooling temperature, and therefore, it is desired to repeatedly use the washing water from the viewpoint of energy saving. However, as mentioned above, the processing water used for them is
When used once, minute oil droplets are mixed in and have various adverse effects, so that an appropriate removal method has been desired.

Conventionally, these fine oil droplets have been physically removed with a microfilter or the like, or removed after adding activated carbon or a flocculant.
The removal cost was unexpectedly high, and the processing capacity was low, which was regarded as a problem.

On the other hand, as a method for separating suspended substances present in water, there is a flotation method in which fine bubbles are introduced into water and bubbles are adhered to the suspended particles for separation. One of the flotation methods is the electrolytic flotation method.

[0008] Regarding the separation of minute oil droplets by the electrolytic levitation method, for example, Japanese Patent Application Laid-Open No. 40286/1990 discloses the electrolysis of fine particles contained in a grinding fluid for machine tool processing or a colloid solution used in civil engineering and construction. It describes that fine particles and hydroxide ions are attached to and floated on metal ions generated and removed. According to JP-A-5-337472, water to be treated passes through a plurality of horizontally arranged electrodes and is further arranged vertically to remove suspended matter remaining in the sewage treated with the flocculant. It is described that electrolysis is carried out while passing through the electrode thus formed, and the suspended matter becomes a floc and is removed by floating. According to JP-A-2-222277,
A plurality of electrodes are installed obliquely, voltage is uniformly applied to the water to be treated, and the generation of floc bubbles is made more efficient. Japanese Patent Application Laid-Open No. 4-300694 discloses a method in which a cylindrical aluminum anode and a cathode of an aluminum thin tube are installed at the center of a cylindrical anode, and while the water to be treated is passed through the cylinder, electrolysis is performed to float suspended substances. Has been removed. JP-A-6-14240
No. 7 discloses a method for preventing scale from being formed and adhered to an aluminum electrode, particularly a cathode, in an electrolytic levitation method. Japanese Patent Application Laid-Open No. Hei 5-50070 discloses that a plurality of insoluble electrodes, each of which is formed by coating a metal substrate such as titanium, tantalum, or niobium with platinum and having a thickness of several μm, and inverting the polarity of the electrodes at regular time intervals, are disclosed. It is described that the water to be treated can be purified by electrolytic levitation for a long time without replacement of the water. Further, JP-A-5-253509
No. 2 describes that a plurality of aluminum electrodes are used as electrodes, the polarity of the electrodes is inverted at regular intervals, and oil is separated from bilge water generated in an engine room of a ship containing oil by an electrolytic flotation method. .

However, the water from which oil droplets have been separated by the electrolytic levitation method is disclosed in JP-A-3-224686 and JP-A-4-2748.
No. 8, etc., when processing by a method using a fixed-bed electrolytic cell, metal ions generated by the electrolytic levitation method are mixed into the treated water, and a compound derived from the metal ion is used to form an electrode in the fixed-bed electrolytic cell. There was a serious problem that clogging was caused and sterilization treatment became impossible in a short time.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a water treatment apparatus and a water treatment method for treating water to be treated containing fine oil droplets and microorganisms to remove the fine oil droplets and microorganisms. is there. More specifically, water that can be stably treated for a long time without clogging of electrodes when separating water droplets by separating micro oil droplets by an electrolytic levitation method and performing sterilization treatment or the like by a fixed-bed electrolytic tank. It is an object to provide a treatment apparatus and a water treatment method.

[0011]

The above objects of the present invention have been attained by the following constitutions.

(1) In a water treatment apparatus having an oil droplet separating means for separating water and oil droplets and a three-dimensional fixed-bed electrolytic cell,
The oil droplet separating means includes an electrode whose anode is made of an amphoteric metal, a power supply for supplying power to the electrode, and a treatment tank containing the electrode and water, and the treatment tank contains fine oil droplets. An inlet for introducing treated water to be treated, and a drain for discharging treated water from the treatment tank, wherein the three-dimensional fixed bed electrolytic cell comprises a fixed bed electrode, and the fixed bed electrode. A power supply that periodically supplies a power whose polarity has been converted, and an electrolytic cell containing the fixed-bed electrode and water, and
The electrolyzer has an inlet for introducing the water to be treated, and a drain for discharging the water to be treated from the electrolyzer. Further, the water to be treated, which has been treated by the oil droplet separating means, is fixed in the three-dimensional manner. A water treatment apparatus, which is arranged to be introduced into a floor-type electrolytic cell.

(2) The water treatment apparatus as described in (1) above, wherein the anode of the oil droplet separating means is an aluminum electrode.

(3) The method according to (1), wherein the electrodes of the oil droplet separating means are a plurality of electrodes made of an amphoteric metal, and the plurality of electrodes are supplied with power whose polarity is periodically converted. A water treatment apparatus as described in the above.

(4) The power supply of the oil droplet separation means and the power supply of the three-dimensional fixed-bed type electrolytic cell are the same power supply, and each is connected in parallel.
The water treatment apparatus according to any one of claims 1 to 3.

(5) The processing tank of the oil droplet separating means is provided at the top with a shielding plate which is arranged obliquely to a horizontal plane and comes into contact with water contained in the processing tank, The above-mentioned 1 characterized in that it has a discharge port guided and discharged by a shielding plate, further has a plurality of amphoteric metal electrodes, and is capable of periodically supplying power whose polarity is converted to the plurality of electrodes. The water treatment apparatus according to any one of claims 4 to 4.

(6) The water treatment apparatus as described in any one of (1) to (5) above, wherein the electrodes of the oil droplet separating means are arranged in a direction perpendicular to a horizontal plane.

(7) The electrode of any one of (1) to (6), wherein the electrodes of the oil droplet separating means are a plurality of electrodes made of an amphoteric metal, and no diaphragm is provided between the plurality of electrodes.
The water treatment device according to the item.

(8) The three-dimensional fixed-bed type electrolytic cell comprises:
8. The water treatment apparatus according to claim 1, wherein the water treatment apparatus is a three-dimensional fixed-bed type bipolar electrolytic cell having a plurality of fixed carbon beds sandwiched between a plurality of metal auxiliary electrodes. 9.

(9) The water treatment apparatus as described in any one of (1) to (8) above, further comprising a filtration means between the oil droplet separation means and the three-dimensional fixed bed type electrolytic cell.

(10) The water treatment according to any one of the items (1) to (9), wherein the anode / cathode current density of the electrode of the oil droplet separating means of the water treatment apparatus is 0.1 A / dm ² or more. Method.

(11) The current concentration in the treatment tank of the oil droplet separation means of the water treatment apparatus according to any one of (1) to (9) is 0.1.
A water treatment method characterized by being at least A / l.

(12) The electric power supplied to the oil droplet separating means of the water treatment apparatus according to any one of the items (1) to (9) is 10 Hz.
Hereinafter, a water treatment method characterized by a ^{frequency of} 1 × 10 ⁻⁵ Hz or more.

(13) A water treatment method, wherein the water to be treated in the water treatment apparatus according to any one of (1) to (9) is food processing water.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to the following embodiments. Generally, when water to be treated containing microorganisms is treated to obtain treated water containing no microorganisms, if it is treated electrochemically, it is efficient and requires no extra chemicals (for example, an antifungal agent or a bactericide). Therefore, it is convenient for reuse of food processing water. In the present invention, a three-dimensional fixed-bed type electrolytic cell is used as an apparatus for performing electrochemical treatment. The three-dimensional fixed-bed electrolytic cell preferably used in the present invention is characterized in that a support is provided at a part of an opening below a cylindrical body accommodating a plurality of fixed-bed three-dimensional electrodes, and And a fixed-bed type bipolar electrolytic cell configured to prevent detachment of the plurality of fixed-bed type three-dimensional electrodes from the electrode.

When the water to be treated containing fine oil droplets is introduced as it is into the three-dimensional fixed-bed bipolar electrolyzer used in the present invention, the fine oil droplets adhere to the electrodes and stop the flow of the water to be treated. , Processing becomes impossible in a short time. The present inventor has tried various methods for removing minute oil droplets without using a chemical substance such as a flocculant in the water to be treated. As a result, the object has been achieved by the water treatment method using the water treatment apparatus having the above-described configuration.

The water treatment apparatus used in the present invention will be described. At least the anode of the electrode in the processing tank of the minute oil droplet separating means is an amphoteric metal. Amphoteric metals include zinc, cadmium, aluminum, gallium, indium, tin,
Although it refers to lead, antimony, bismuth, etc., in the present invention, aluminum is most preferably used for environmental reasons. By using aluminum for the electrode, aluminum ions eluted in a small amount in the course of electrolysis, agglomerated suspended substances contained in the treated water, and helped to collect large oil droplets to become large oil droplets, In addition, minute hydrogen bubbles generated on the cathode surface adhere to the surface of the oil droplet to promote separation of the oil droplet and the treated water. Moreover, since the aluminum ions are discharged together with the minute oil droplets, the aluminum ions are hardly contained in the water to be treated. Further, even if it is contained, the amount is extremely small, and there is no problem when used in food processing water or the like. The cathode may also be an amphoteric metal, in which case the most preferred metal is aluminum. Further, in the present invention, when the plurality of electrodes are made of an amphoteric metal and the polarity of the electrodes is periodically changed, the electrodes are worn down on average and the surface of the electrodes becomes rough, so that the electrodes are generated by electrolysis. The generated bubbles are smaller, and the efficiency of separating oil droplets is improved.

The electrodes in the processing tank of the fine oil droplet separating means of the present invention are arranged vertically to facilitate floating of the fine oil droplets, and the floating oil droplets are discharged from the discharge port by the obliquely disposed shielding plate. It is led to a certain floc foam outlet and discharged. On the other hand, at the lower part of the treatment tank, a solid substance discharge port which is a solid substance discharge part for periodically removing solid substances coming into the water to be treated is provided, and the inside of the treatment tank is closed by solid substances. And the separation of minute oil droplets can be performed smoothly. In addition, when there is a large amount of solid matter, it is preferable to attach a filter before introducing the water to be treated into the treatment tank. It is preferable that the thing is not introduced into the electrode part by following the liquid flow.

In the present invention, the cathode current of the electrode of the treatment tank of the micro oil droplet separation means is 0.1 A / dm ² or more, preferably 0.15 to 5.0 A / dm ² . The current concentration in the treatment tank of the micro oil droplet separation means is 0.1 A / l or more, but is preferably 0.15 to 10 A / l.

The water treatment apparatus used in the present invention will be described with reference to the drawings. FIG. 5 shows a block diagram of a water treatment apparatus in which the oil droplet separating means of the present invention is connected to a three-dimensional fixed-bed bipolar battery. The water to be treated is introduced into the treatment tank 1 of the oil droplet separating means from the treated water inlet 10, the separated oil droplets are discharged from the floc foam outlet 4, and the treated water is discharged from the treated water outlet 2. The treated water from which the oil component has been separated passes through a filtration facility 35 connected to a water passage, removes solids, and is introduced into a three-dimensional fixed-bed bipolar electrode tank 36. The treated water sterilized in the three-dimensional fixed-bed bipolar electrolytic cell 36 is used again as treated water from the outlet 37. Further, in the present invention, a power supply for supplying power to the oil droplet separation means and a power supply for supplying power to the three-dimensional fixed-bed type bipolar electrolytic cell 36 are a common power supply 38.
The power supply terminals 7 and 8 of the processing tank 32 of the oil droplet separation means are connected in parallel with the electrode terminals 24 and 24 'of the three-dimensional fixed-bed bipolar electrode tank 36.
With this configuration, excessive power is not supplied to the three-dimensional fixed-bed bipolar battery that occurs when the battery is connected in series. In addition, when different power supplies are used, there is no problem such as electricity leaking through water. The power supply 38 periodically converts the polarity and supplies power, and is an alternating current of 10 Hz or less and 1 × 10 ⁻⁵ Hz or more.

In FIG. 1, the treatment tank 1 of the oil droplet separation means is provided with a treated water outlet 2 and a floc foam outlet 4 at the upper part, and treated water is introduced from a treated water inlet 10 at the lower part. Introduced water to be treated is subjected to large solids to settle in the lower solids separation section 13 and to accumulate near the solids outlet 12. The water to be treated containing fine oil droplets rises and passes through the electrode unit 14. FIG. 2 shows a perspective view of the electrode portion 14. One aluminum electrode 5 is connected to the electrode rod 19 at the connection portion 16 and is provided every other electrode. The other aluminum electrode 6 is connected to the electrode rod 18, but the aluminum electrode 5
The hole 17 is provided with a hole so as not to contact the aluminum electrode 5 so that the electrode rod 18 can pass freely. A similar procedure is performed on the aluminum electrode 6 so that the electrode rod 19 does not contact the aluminum electrode 6. Further, in the present invention, there is no diaphragm between the electrodes. The electrode rods 18 and 19 are connected to the power supply terminals 7 and 8, respectively,
And 8 are connected to a power supply 38, and power having different polarities is supplied from the outside. Each of the power supply terminals 7 and 8 is supplied with power by periodically changing the polarity. That is, while positive power is being supplied to the power supply terminal 7, negative power is supplied to the power supply terminal 8. Conversely, when negative power is being supplied to the power supply terminal 7, positive power is supplied to the power supply terminal 8. The power frequency is 10 Hz or less and 1 × 10 ^-5 Hz or more as described above. Therefore, in the electrode portion 14, electrolysis occurs between the respective aluminum electrodes 5 and 6, minute hydrogen bubbles generated at the cathode adhere to the surface of the oil droplets, the specific gravity becomes extremely small, and at the same time, relatively large floc bubbles occur. And rise. The rising floc foam is separated by the floc foam separating section 15,
It is guided to the floc foam outlet 4 by the obliquely provided shielding plate 3 'and discharged to the outside. The to-be-treated water from which the minute oil droplets have been separated is collected from the treated water outlet 2 and used again for treatment. A shielding plate 3 is provided in parallel with the shielding plate 3 'to prevent separation of minute oil droplets so that floc bubbles do not enter the treated water. The shielding plate is installed at an angle of 30 ° with respect to the horizontal plane. The shielding plates 3 and 3 'are plates for separating water from bubbles, such as minute nets and perforated plates. The processing tank 1 is installed vertically by a flange 9 and has a rectangular horizontal section. The solids are discharged periodically by opening the valve 11 installed in the solids outlet 12. As the power supply, a power supply that can periodically change the polarity may be used, or a power supply that can periodically convert the polarity of the power may be provided as a normal power supply to be the power supply of the present invention. Each aluminum electrode is preferably plate-shaped, but may be rod-shaped. The horizontal cross section of the processing tank 1 is not limited to a rectangle but may be a circle or the like.

Next, the three-dimensional fixed bed type bipolar electrolytic cell of the present invention will be described. When the three-dimensional fixed-bed bipolar electrode is used for the treatment of the water to be treated, the applied potential is set to +0.2 to +1.2 where the anode potential does not substantially involve oxygen generation.
V (vs. SCE) and the cathode potential are desirably 0 to -1.0 V (vs. SCE) substantially without generation of hydrogen. When the change in the properties does not occur or when the reaction amount does not matter so much, the anode potential is set to +1.6 V (vs. SH).
E), and the cathode potential is -1.5 V (vs.
SHE). Alternatively, if the electrode reaction is not a problem, a higher potential may be applied.

In the case of reforming the water to be treated, if gas is generated in the case of mass treatment, the generated gas, that is, the oxygen gas and the hydrogen gas are usually generated at a mixing ratio within the explosion limit, thereby avoiding the danger of explosion. For this purpose, it is desirable to dilute with an inert gas such as air. For example, a means for separating electrolytic gas generated at the outlet of a three-dimensional fixed-bed bipolar electrolytic cell and diluting the separated electrolytic gas with air to obtain an electrolytic gas An electrolytic gas diluting means using air can be provided so that the hydrogen gas concentration in the medium becomes 4% by volume or less.

The electrodes in the three-dimensional fixed-bed bipolar electrode of the present invention include a fixed-bed three-dimensional electrode and a power supply electrode, and are porous materials through which water to be treated can pass, for example, granular, spherical, and felt-like. , Activated carbon having a shape such as a woven fabric, a porous block shape, graphite, carbon fiber, carbonaceous material such as glassy carbon, or nickel having the same shape,
A plurality of preferably granular, spherical, fibrous, felt, woven, porous materials formed from metallic materials such as copper, stainless steel, iron, titanium, and the like, and materials coated with a precious metal. A block-shaped or sponge-shaped electrode can be used as a fixed-bed type three-dimensional electrode. In addition, the fixed-bed-type electrode means an electrode that hardly moves with respect to a fluid electrode in which the electrode is dispersed in a liquid. Normally, if fixed, an operation such as moving the electrode may be performed periodically.

In the present invention, the fixed bed type three-dimensional electrode is preferably porous graphite having an average pore diameter of 20 to 100 μm. These are, for example, a plurality of vegetable fiber sheets laminated using an organic binder, for example, Japanese paper, and the like. It is a floor type three-dimensional electrode plate. More preferably, a plurality of synthetic fiber sheets are laminated and pressed using an organic binder, and then heat-treated and carbonized, and further heat-treated and graphitized to form a porous fixed-bed type three-dimensional electrode plate with less impurities. It is preferable because the pore diameter can be easily controlled. In particular, since the width of the pore diameter distribution becomes narrower and narrower than the target pore diameter, clogging hardly occurs. As the organic binder used for such an application, a thermoplastic resin such as a phenol resin, an epoxy resin, a furan resin, and a divinylbenzene resin can be used, but it is not particularly limited thereto. The sheet made of synthetic fiber may be woven in a cloth form, but non-woven cloth is preferred.

The plurality of fixed floors are accommodated in a tubular body having upper and lower ends open. The tubular body is preferably formed of an electrically insulating material that can withstand long-term use or re-use. In particular, synthetic resins such as polyepichlorohydrin, polyvinyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, and poly (ethylene chloride) , Phenol-formaldehyde resin, ABS resin, acrylic resin, polycarbonate and the like can be used. Further, it is more convenient to form the fixed bed by using a transparent or translucent material since the consumption state of the fixed bed can be visually recognized.

Since the diameters of the plurality of fixed floor type three-dimensional electrodes accommodated in the cylindrical body are equal to or slightly smaller than the inner diameter of the cylindrical body, only the cylindrical body is gripped and When an operation such as replacement of the fixed-bed type three-dimensional electrode is performed, the fixed bed separates from the lower opening, and a predetermined number of fixed beds cannot be accommodated in the cylindrical body.

Therefore, in the three-dimensional fixed-bed bipolar battery according to the present invention, a support is installed so as to close a part of the opening below or above the cylindrical body, and the fixed bed is detached. That is, it is preferable to prevent falling from the cylindrical body. The shape of the support is not particularly limited as long as it has enough strength to suppress the movement of the plurality of fixed beds, and a donut-shaped body is provided at a lower end of the cylindrical body so that the donut-shaped body is part of an opening. It is fixed by welding, bonding, etc. so as to close it, or a member having the same shape as this is integrally molded, and a cross-shaped member is fixed by bonding, etc. so as to straddle the circumferential portion at the lower end of the cylindrical body Alternatively, a mesh can be similarly placed within the closure. Further, a screw may be engraved on the donor-shaped body and the cylindrical body, and both members may be screwed and fixed to each other. Similarly, a support can be provided at the upper portion of the opening by screwing, so that the fixed floor can be accommodated in the tubular body in a more stable state.

The cross section of the support in the direction perpendicular to the flow direction of the water to be treated is desirably 3 to 50% of the opening area of the opening, and if it is less than 3%, the support is insufficient due to insufficient strength. From the cylindrical body is liable to occur, and if it exceeds 50%, the flow of the water to be treated is hindered and the electrolysis voltage tends to increase.

The fixed bed is placed in a DC or AC electric field, and a DC or AC voltage is applied between power supply electrode terminals made of a porous plate such as a flat plate, expanded mesh, or perforated plate provided at both ends. The fixed bed can be polarized to form a fixed-bed type bipolar electrolytic cell containing a three-dimensional electrode formed by polarizing an anode and a cathode at one end and the other end of the fixed bed, respectively. Alternatively, a three-dimensional material functioning independently as an anode or a cathode may be installed so as not to be alternately short-circuited and electrically connected to form a fixed-bed bipolar electrolyzer.

Examples of the material of the power supply anode terminal include a carbon graphite material (carbon fiber, carbon cloth, graphite, etc.), a carbon composite material (a material obtained by mixing a metal with powder in carbon and sintering, etc.), an activated carbon fiber, and the like. A nonwoven fabric (for example, KE-1000 felt, Toyobo Co., Ltd.) or a material on which platinum, palladium, nickel or the like is supported, a dimensionally stable electrode (a platinum group oxide-coated titanium material), a platinum-coated titanium material, a nickel material, Stainless steel,
There is a material formed from an iron material or the like. The power supply cathode terminal that faces the power supply anode terminal and applies a DC voltage is, for example, platinum, stainless steel, titanium, nickel, copper,
It can be formed from Hastelloy, graphite, a carbon material, a soft copper or a metal material coated with a platinum group metal.

Activated carbon, graphite,
When using a carbon-based material such as carbon fiber and treating water to be treated while generating oxygen gas from the anode, the fixed bed is oxidized by oxygen gas and easily dissolved as carbon dioxide gas. Alternatively, fine powder of the collapsed electrode material is generated. In order to prevent this, a porous material which is usually used as an insoluble metal electrode by coating a platinum group metal oxide such as iridium oxide or ruthenium oxide on a substrate such as titanium on the side of the fixed bed to be positively polarized or The reticulated material may be placed in contact so that oxygen evolution occurs primarily on the material.

FIG. 3 is a longitudinal sectional view of a three-dimensional fixed bed type bipolar electrolytic cell of the present invention. The water to be treated introduced from the upper inlet (IN) reaches the lower part through a space 27 (treatment water introduction passage) between the inner cylinder 25 and the outer cylinder 26 of the electrolytic cell. The water to be treated is transferred to the upper part according to the arrow. At this time, the electrode terminals 24, 2
The power whose polarity has been periodically converted is supplied from 4 ′, and the fixed floor type three-dimensional electrode 21 sandwiched between the auxiliary electrodes 22 and 22 ′.
When passing through, the bacteria contained in the water to be treated are sterilized. The power supplied from outside is the electrode terminal 2
4, the power supplied to the auxiliary electrode 22 via the power supply electrode 30 and to the electrode terminal 24 'reaches the lower portion via the conductor 28 and is supplied to the auxiliary electrode 22' via the power supply electrode 30 '. Since the fixed floor type three-dimensional electrode is sandwiched and laminated between the auxiliary electrodes 22 and 22 ', it is polarized from the lower part to the upper part. Each of the fixed-bed type three-dimensional electrode 21 and the auxiliary electrodes 22, 22 'is closed by a gasket 23 so that water to be treated does not leak from the side. These pairs are
The lower fixing ring 31 and the spacer 29 at the bottom are stacked and set, and the upper lid 20 and the outer cylinder 26 are assembled with screws. The power supplied to the fixed-bed type three-dimensional electrode by the power source is preferably 0.5 A or less,
The alternating current is preferably 0 Hz or less and 1 × 10 ⁻⁵ Hz or more. Even if the fixed bed electrode is clogged with a compound derived from metal ions, such as aluminum hydroxide, generated in the oil droplet separation means and mixed into the treated water, the generated metal ions are ions of the amphoteric metal. In addition, by periodically changing the polarity, aluminum hydroxide is converted into aluminum ions again and dissolved, so that clogging of the electrode can be prevented, and water treatment can be stably performed over a long period of time.

FIG. 4 is an exploded perspective view of a three-dimensional fixed-bed bipolar battery containing a fixed bed according to the present invention. A fixed floor is inserted from the inner cylinder 25 and laminated, and furthermore, a fixing ring 31 is fitted to a screw at the bottom, and assembled with the screw inside the upper lid 20 to prevent water leakage. After connecting the conductive wire 28 to the lower power supply electrode 30 ′, the outer cylinder 26 is screwed to the upper lid.

The water to be treated applied to the water treatment method of the present invention is preferably food processing water. In the food processing water, it is necessary to minimize mixing of unnecessary compounds into the processed food. In that regard, according to the water treatment method of the present invention, flocculants, fungicides, disinfectants and other chemicals, without using special equipment for oil separation and removal, to separate micro oil droplets of the water to be treated, Microorganisms can be sterilized, which is preferable.

[0046]

【Example】

Example 1 Water to be treated was treated by the water treatment apparatus shown in FIG. More specifically, the pretreatment is performed in the treatment tank shown in FIG. 1 of the present invention, temporarily stored in an oil-water separation facility as shown in FIG. 5, passed through a filtration facility, and then passed through a three-dimensional fixed-bed bipolar pole shown in FIG. It was introduced into an electrolytic cell and processed. The treated water used is water having the following conditions.

General bacteria separated from the ion-exchanged water on a normal agar medium (manufactured by Eiken Chemical) are cultured for 3 days in a liquid medium (normal broth medium, manufactured by Eiken Chemical), and the cells are cultivated for 50 days.
After centrifugation at 00 rpm, it was washed with pure water and centrifuged again. This was previously added to stored tap water (having a residual chlorine concentration of 0.02 ppm or less) containing 300 ppm of oil droplets of 1 to 100 μm to obtain treated water. The viable cell count was 6.5 × 10 ⁴ CFU.

The treatment tank was operated under the following conditions to separate micro oil droplets.

Electrolysis conditions Anode: aluminum (anode current density 0.15 A / d
m ² ) Cathode: aluminum (cathode current density 0.15 A / d)
m ² ) Electrolysis voltage: 8.0 V Treatment tank conditions Treatment tank current concentration: 0.12 A / l Electrolysis current: AC of 10 Hz or less (power supply is common to three-dimensional fixed-bed bipolar electrode) Current waveform: Pulse current or smooth current with ripple rate of 5% or less Residence time in processing tank: 5.6 seconds Distance between electrodes: 10 mm.

The three-dimensional fixed-bed bipolar electrode is a titanium mesh (1 mm thick) coated with platinum as an auxiliary electrode.
And 34 V DC was applied to the electrode terminals.

As a result of treating 1 m ³ of the water to be treated, there was no clogging, and the number of viable bacteria was reduced to 63 CFU in the treated water at the outlet of the three-dimensional fixed-bed bipolar electrode tank. Further, the masking of the graphite electrode of the three-dimensional fixed-bed bipolar electrode tank with oil does not change the electrolysis voltage and electrolysis current.
It is proven that it has not occurred.

Example 2 Using the apparatus of Example 1, the washing water of the broiler was continuously treated for one week. Broiler wash water 1 ~ 100μ
Although it was water containing 200 to 500 ppm of micro oil droplets of m and containing some viable bacteria, even after one week, there was no clogging, and the viable bacteria were 100 CFU or less, and no practical problem was observed.

[0053]

According to the present invention, water to be treated containing micro oil droplets and microorganisms can be stably treated for a long period of time.

[Brief description of the drawings]

FIG. 1 is a sectional view of the inside of a processing tank of an oil droplet separating means.

FIG. 2 is a perspective view of an electrode section in a processing tank.

FIG. 3 is a longitudinal sectional view of a three-dimensional fixed-bed bipolar battery.

FIG. 4 is an exploded perspective view of a three-dimensional fixed-bed bipolar battery.

FIG. 5 is a block diagram of the water treatment apparatus of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 treatment tank 2 treated water outlet 3 shielding plate 3 ′ shielding plate 4 floc foam outlet 5 electrode 6 electrode of different polarity 7 power supply terminal 8 power supply terminal of different polarity 9 flange 10 treated water inlet 11 valve 12 solids outlet DESCRIPTION OF SYMBOLS 13 Solid separation part 14 Electrode part 15 Floc foam separation part 16 Connection part 17 Hole 18 Electrode rod 19 Electrode rod of different polarities 20 Top lid 21 Fixed floor type three-dimensional electrode (for example, carbon electrode) 22 Auxiliary electrode 22 'Auxiliary electrode 23 Gasket 24 Electrode terminal (for power supply from outside) 24 'Electrode terminal (for power supply from outside) 25 Inner tube 26 Outer tube 27 Water introduction path 28 Conductor 29 Spacer 30 Power supply electrode 30' Power supply electrode 31 Lower part fixing Ring 32 Treatment tank of oil droplet separation means 35 Filtration equipment 36 Three-dimensional fixed-bed bipolar type Solution tank 37 outlet 38 Power

Claims (13)

[Claims] 1. A water treatment apparatus having an oil droplet separating means for separating water and oil droplets and a three-dimensional fixed-bed electrolytic cell, the oil droplet separating means comprising: an electrode having an anode made of an amphoteric metal; A power supply for supplying electric power, a treatment tank containing the electrodes and water, and the treatment tank is provided with an inlet for introducing the water to be treated containing fine oil droplets, and the treated water to be treated is subjected to the treatment. The three-dimensional fixed-bed electrolytic cell has a drainage outlet for discharging from the tank, the fixed-bed-type electrode, a power supply that periodically supplies the fixed-bed-type electrode with power whose polarity has been converted, and It comprises a floor-type electrode and an electrolytic cell containing water, and the electrolytic cell has an inlet for introducing the water to be treated, and a drain port for discharging the treated water after the treatment from the electrolytic cell. The water to be treated, which has been treated by the droplet separation means, is introduced into the three-dimensional fixed-bed electrolytic cell. A water treatment device, wherein the water treatment device is disposed. 2. The water treatment apparatus according to claim 1, wherein the anode of said oil droplet separating means is an aluminum electrode. 3. The method according to claim 1, wherein the electrodes of the oil droplet separating means are a plurality of electrodes made of an amphoteric metal, and the plurality of electrodes are supplied with power whose polarity is periodically converted. A water treatment apparatus as described in the above. 4. A power supply according to claim 1, wherein a power supply of said oil droplet separating means and a power supply of said three-dimensional fixed-bed electrolytic cell are the same power supply, and are connected in parallel. The water treatment device according to claim 1. 5. A processing tank of the oil droplet separating means,
A shielding plate that is arranged obliquely with respect to a horizontal plane and comes into contact with water contained in the processing tank, and a discharge port through which the floating minute oil droplets are guided and discharged by the shielding plate; The water treatment apparatus according to any one of claims 1 to 4, further comprising a metal electrode, and capable of periodically supplying a power whose polarity is converted to the plurality of electrodes. 6. An electrode of the oil droplet separating means is arranged in a direction perpendicular to a horizontal plane.
The water treatment apparatus according to any one of claims 5 to 5. 7. The method according to claim 1, wherein the electrodes of the oil droplet separating means are a plurality of electrodes made of an amphoteric metal, and no diaphragm is provided between the plurality of electrodes. A water treatment apparatus as described in the above. 8. The three-dimensional fixed-bed electrolytic cell having a plurality of carbon fixed beds sandwiched between two metal auxiliary electrodes, wherein the three-dimensional fixed-bed electrolytic cell has a plurality of carbon fixed beds sandwiched between two metal auxiliary electrodes. Item 1
The water treatment apparatus according to any one of claims 1 to 7. 9. The apparatus according to claim 1, further comprising a filtering means between said oil droplet separating means and the three-dimensional fixed-bed electrolytic cell.
The water treatment apparatus according to any one of claims 8 to 13. 10. The anode / cathode current density of the electrode of the oil droplet separating means of the water treatment apparatus according to claim 1,
A water treatment method characterized by being 0.1 A / dm ² or more. 11. The current concentration in the treatment tank of the oil droplet separation means of the water treatment apparatus according to any one of claims 1 to 9 is 0.1 A /.
1 or more. 12. The water treatment according to claim 1, wherein the power supplied to the oil droplet separating means of the water treatment apparatus is 10 Hz or less and 1 × 10 ⁻⁵ Hz or more. Method. 13. A water treatment method, wherein the water to be treated in the water treatment apparatus according to claim 1 is food processing water.