JP2001293474A - Seawater purification method and seawater purification device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To safely treat a large amount of water to be treated without worrying about secondary pollution. SOLUTION: The inside of a container 2 is partitioned into a cathode portion 9 and an anode portion 8 by a diaphragm 5, a conductive substance is put in the anode portion 8, and the cathode portion 9 is covered with seawater or a mixed water containing seawater. The treated water is charged, and the anode 3 and the cathode 9 in the anode 8 are treated.
A voltage is applied between the cathodes 4 to generate a treatment species in the cathode portion 9. The treatment species causes plankton in the water to be treated,
It treats treated water by killing plankton cysts, bacteria and viruses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying seawater, which kills plankton, plankton cysts, bacteria, viruses and the like present in the water to be treated such as seawater or mixed water containing seawater, and treats the water to be treated. And its device.

[0002]

2. Description of the Related Art Water to be treated, such as seawater, mixed water containing seawater, etc., is used for ballast water for ships, cooling water for power plants, factories, plants, etc., and breeding water for aquariums, aquaculture expansion and the like. However, since seawater contains plankton, plankton cysts, bacteria, viruses, etc., when seawater is discharged to other seas, it may affect the ecosystem of marine organisms, condensers, heat exchangers Bacteria-derived slime may adhere to the inner surface of the pipe, causing a decrease in heat exchange rate or blockage of the pipe.

For example, a case where seawater is used as ballast water will be described. Ballast water means that when a ship does not carry any cargo or has a small amount of cargo, the draft line is lowered and it is difficult to maintain balance. Seawater is discharged to the sea area outside the ship when loading cargo at the destination port or before entering the cargo loading port. In seawater, closed and polluted inner bays contain plankton that are harmful to fish and shellfish, etc., which may become unsuitable for environmental conditions (eg, water temperature, light, nutrient concentrations, etc.). It is known that they form cysts and die themselves. Cysts are completely different from plankton cell wall membranes and are covered with a very strong outer wall, and it is said that they will not die for several years even in a bad environment such as a dark place or a reduced state.
The cysts settle down and accumulate on the sea floor, but germinate again when environmental conditions improve. At this time, a large amount of germination at once,
It is well known that the multiplication is a phenomenon called red tide, which kills fish and shellfish, and in particular, seriously damages aquaculture. Also, once the red tide plankton is generated, if the surrounding environmental conditions are no longer suitable for growth, it will again form a cyst and die itself. Then, such a cycle is repeated.

As described above, in the case of a ship, seawater is supplied into a tank as ballast water. Ballast water is usually seawater in a bay, and when plankton, particularly harmful plankton, inhabits the bay, the ballast water is removed. It is taken into the tank together. Since there is no light in the tank and it is not suitable for the growth of plankton, plankton forms a cyst and enters a dormant state as described above. When a ship discharges ballast water at a foreign port of call after sailing, cysts are discharged at the same time, and the discharged cysts germinate due to improved environmental conditions.
And since ships sail and call around the world, if the cyst is a harmful plankton cyst, the harmful plankton will spread all over the world.

[0005] The occurrence of red tide of harmful plankton due to the germination of such cysts, the discharge of ballast water at foreign ports of call of ships, and the pollution of water due to the global diffusion of harmful plankton due to water supply become serious problems. Sometimes. As a countermeasure against this problem, a reballast (ballast water exchange) in the open sea may be performed. However, this method has many problems, such as hull safety issues, difficulties in sea conditions, weather conditions and short-haul routes, and an increase in the labor burden of seafarers. Hard to say.

Means for purifying seawater for treating seawater by killing plankton, plankton cysts, bacteria, viruses, etc. existing in the water to be treated include filtering, heat treatment, electric treatment, ultraviolet treatment, and chemicals. Etc. are proposed.

[0007]

However, when the amount of water to be treated is large, it is physically difficult to carry out effective treatment with filtering, heat, electricity and ultraviolet light, and it is not economical. It is said that sodium hypochlorite, aqueous hydrogen peroxide, formaldehyde, ozone and the like are effective in the treatment using chemicals. For example, as a controlling agent for red tide plankton such as Rhizosolenia setigera or Prolocentrum mikans, a method of applying hydrogen peroxide, calcium peroxide, and hydrogen peroxide has been studied [Japanese Unexamined Patent Publication No. Sho.
No. 5,141,142; Study on "Shattonella marina, a study on red tide controlling agents-especially the ability to remove free radicals generated from hydrogen peroxide and highly unsaturated fatty acids", Nip
ponsuisan Gakkaishi 55 (6) 1075-1082 (1989)]. However, the use of these chemicals is enormous, and the safety of storage is concerned.Sodium hypochlorite, ozone, etc., are particularly susceptible to secondary pollution of the environment and hull corrosion due to oxidants remaining after treatment. There is fear. Therefore, there are some issues and problems in all methods,
At present there is no way to be decisive. Therefore, the present invention has been made in view of such a situation, and an object of the present invention is to provide a method for purifying seawater and a method for purifying seawater that can safely treat a large amount of water to be treated and have no concern about secondary pollution of the environment. It is to provide a purification device.

[0008]

Means for Solving the Problems The present inventors applied an on-site generation technique of hydrogen peroxide. That is, it is generally known that when a weak voltage is applied using a carbon electrode, the following reaction occurs at the cathode and hydrogen peroxide ions are generated (for example, by Masao Sudo, Chemical Engineering, Vol. 51, N
o.6, p417-419 (1987)). O ₂ + H ₂ O + 2e ⁻ → HO ₂ ⁻ + OH ⁻ (1) or a redox compound or a redox resin (Q) on the cathode
It is also known that when electricity is supplied in the presence of hydrogen, the following reaction turns over and hydrogen peroxide is generated (for example, Japanese Patent Application Laid-Open No. 61-284591). Q + nH ⁺ + ne ⁻ → H _n Q (2) H _n Q + (n / 2) O ₂ → Q + (n / 2) H ₂ O ₂ (3) Similarly, a conductive polyaniline (PA) is used as a cathode. It is also known that, when energized by being supported on an electrode, the following reaction proceeds in a cycle to generate hydrogen peroxide (K. Mori
ta et.al, Chem. Lett., 1996, p615, or ibid, vol.1
5, No. 5 (1997)). ^{PA + nH + + ne - →} H n PA (4) H n PA + (n / 2) O 2 → PA + (n / 2) H 2 O 2 (5) However, to take advantage of these reactions, When the anode and cathode are immersed in seawater and energization is continued, acids such as hypochlorous acid are generated from the anode by the following reaction mechanism, causing not only corrosion of equipment but also secondary pollution of seawater. . ^{_{2Cl - → Cl 2 + 2e -}} Cl 2 + H 2 O → HOCl + HCl (6) Accordingly, the present inventors have by separating the anode and cathode with a diaphragm, to generate hypochlorous acid in seawater The present inventors have found that the above problems can be overcome by producing seawater treated species without any problem, and have completed the present invention.

That is, according to the method of purifying seawater of the present invention, the inside of the container is partitioned into a cathode portion and an anode portion by a diaphragm, a conductive substance is put in the anode portion, and seawater or a mixed water containing seawater is put in the cathode portion. The water to be treated is charged, and a voltage is applied between the anode in the anode part and the cathode in the cathode part to generate a treatment species in the cathode part, and plankton, plankton cysts, bacteria, and viruses in the treatment water are treated by the treatment species. The water to be treated is treated by being killed.

Further, in the apparatus for purifying seawater of the present invention, a cathode portion into which water to be treated enters seawater or mixed water containing seawater and an anode into which a conductive substance enters are provided in a vessel provided with a cathode and an anode to be energized. And a partition, and at least a part of the partition, a diaphragm is disposed so that a current flows between the electrodes, and the cathode is used to discharge plankton, plankton cysts, bacteria, and viruses in the water to be treated by energization. It is a treatment electrode that generates a treatment species that kills and treats the water to be treated.

The conductive substance is an alkaline buffer or an alkaline aqueous solution, a storage tank for storing the conductive substance is provided, and a part of the conductive substance in the storage tank is supplied to the anode. Thereafter, it is preferable to provide a circulating means for returning to the liquid storage tank. It is preferable to provide an oxygen-containing gas mixing means for mixing an oxygen-containing gas into the water to be treated to the cathode section. Preferably, the processing electrode is a carbon-based electrode. It is preferable that the treated electrode is an electrode carrying an organic compound having a redox ability. It is preferable that the treatment electrode is an electrode carrying a redox resin. The treatment electrode is preferably a carbon-based electrode or an electrode carrying an organic compound having a redox ability. It is preferable that the treatment electrode is a carbon-based electrode or an electrode carrying a redox resin. Preferably, the treatment electrode is a carbon-based electrode or an electrode carrying an organic compound or an oxidation-reduction resin having a redox ability. It is preferable that the organic compound having the redox ability is benzoquinone, naphthoquinone, anthraquinone, or a derivative thereof. The redox resin is preferably a quinone-based redox resin. Preferably, the redox resin is polyaniline.

The conductive substance is preferably an alkaline buffer solution or an aqueous alkaline solution in order to suppress pH fluctuation. When the conductive substance is a buffer solution or an aqueous alkaline solution, it is preferable to provide a stirrer for stirring the solution so that protons generated from the electrodes can be efficiently neutralized. In addition, since the alkaline aqueous solution is harmful if it leaks out of the anode part due to some kind of obstacle, it is preferable to add a gelling agent to form a sol-gel electrolyte.

As described above, according to the present invention, since the cathode is the treatment electrode, a treatment species is generated from the cathode, and this treatment species causes plankton containing harmful plankton, plankton cysts, bacteria, viruses and the like in the water to be treated. Died and
Since the cathode and anode are separated by a diaphragm, harmful organic acids such as hypochlorous acid can be prevented from being generated from the electrode surface, and there is no risk of secondary contamination of the water to be treated. A large amount of water to be treated can be safely treated.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 and 2 are diagrams showing a first example of a seawater purification apparatus of the present invention. 1 and 2, reference numeral 1 denotes a seawater purification apparatus that treats plankton, plankton cysts, bacteria, viruses, and the like that are present in the base water, such as seawater or mixed water containing seawater, to treat the base water. . The container 2 of the seawater purification device 1 may have any shape and is not particularly limited. For example, a container having a rectangular cross section, a polygonal shape, a circular shape, or the like is used. Further, since the container 2 can process a large amount of water to be treated, a pipe having a circular, rectangular or polygonal cross section is preferable. The material of the container 2 is not particularly limited as long as it is insulative and is not eroded by seawater.
Synthetic resins such as polyvinyl chloride are exemplified. Also,
Naturally, a metal material whose inner surface is subjected to insulation treatment can also be used.

In the first example, the container 2 is formed in a pipe shape having a rectangular vertical section, as shown in FIGS. An anode 3 is provided on one side surface of the container 2, and a cathode 4 is provided on a side surface facing the one side surface. The shape of the anode 3 and the cathode 4 is not particularly limited, but a plate, a net, or a rod is preferably used. For example, a plate-shaped (rectangular) dimensionally stable electrode is used, and these electrodes 3 and 4 are provided on the side surfaces as shown in the figure. The anode 3 and the cathode 4 may be continuous in the longitudinal direction of the container 2, and a plurality of anodes 3 and cathodes 4 may be provided at predetermined intervals with a plate-like electrode having a predetermined length as shown in the figure. May be provided so as to face each other.

The anode 3 is a counter electrode for generating a treatment species such as hydrogen peroxide on the cathode 4 by electrolysis, and is not particularly limited. However, since elution of the anode material may contaminate the diaphragm 5, an alkaline solution It is preferable to use a metal that does not elute in the metal and has high resistance to the oxidation reaction.
As the anode material, for example, gold, platinum, iridium, ruthenium, nickel, titanium, etc., which have a small overvoltage and are extremely small in consumption as compared with other metals and oxides, and thus can be used with little change over a long period of time. Metals or their oxides can be used. Further, a metal web having a large surface area per unit area can be used.
Examples of the material of the metal web include nickel, stainless steel, iron, copper, platinum, and alloys thereof.

The cathode 4 is an electrode for generating seawater treatment species such as hydrogen peroxide and active oxygen when energized, and is not particularly limited as long as it can be applied to on-site hydrogen peroxide production. Examples include felt, graphite, a carbon fiber material, a porous amorphous carbon molded article, and an organic compound or resin having a redox ability. Examples of graphite include those obtained by extruding and firing coke, those obtained by molding and firing, and those obtained by CIP molding and firing. Examples of the carbon fiber material include a knitted carbon fiber, and examples of the knitted carbon fiber include a commercially available CF cloth. Carbon fiber materials other than CF cloth may be used. Glassy carbon (glassy carbon) can be exemplified as the porous amorphous carbon molded body. Examples of the organic compound having redox ability include benzoquinone, naphthoquinone, anthraquinone, and derivatives thereof.
Examples of the derivative include, for example, methoxybenzoquinone, 2-tert-butylbenzoquinone, 2,5-
Diphenylbenzoquinone, 2,6-dimethylbenzoquinone, 2,6-di-tert-butylbenzoquinone, 2-
Methylanthraquinone, 2-ethylanthraquinone, 2
-Tert-butylanthraquinone, 1-nitroanthraquinone, 1- (or 2-) chloroanthraquinone,
1,5- (or 1,4- or 1,8-) dichloroanthraquinone and the like. Examples of the redox resin include a quinone-based redox resin, polyaniline, and the like. As an electrode carrying a quinone-based redox resin,
Hydroquinone-formaldehyde condensation resins (Manecke, Z. Elektrochem., 57 , 189 (1)
953)) and hydroquinone- (diazotized poly-p-aminostyrene) condensation resin (Rao et al., Chem. Ind. (London), 145 (1)
961)), 2-formyl anthraquinone-polyvinyl alcohol condensed resin (Izoret)
Ann. Chim., 254 , 671 (1962)).
However, it is not limited to these. In order to carry these compounds or resins on the electrode, a method of dissolving or dispersing in methanol, isopropyl alcohol, acetone, a halogen solvent or the like, then immersing the supporting substrate in the solution, pulling it up, and air-drying, or spraying the solution is used. Means for applying to the supporting substrate by a method or the like is used. The support substrate is not particularly limited as long as it is conductive, and a carbon electrode such as graphite, CF cloth, graphite, or a metal electrode such as titanium platinum or copper mesh is used. These support substrates may be surface-treated with a silane-based or titanium-based coupling agent or the like in order to increase the adsorptivity of the organic compound. The electrode supporting the conductive polymer polyaniline is a commercially available polyaniline dispersion solution (ORMECON ^™ Disperse manufactured by ORMECON).
The support substrate can be manufactured by immersing the support substrate in ion 900132), pulling it up, and air-drying, or applying the solution to the support substrate by a spray method or the like. The support substrate is not particularly limited as long as it is conductive, and a carbon electrode such as graphite, CF cloth, and graphite, and a metal electrode such as titanium platinum and copper mesh are used. These support substrates may be surface-treated with a silane-based or titanium-based coupling agent or the like in order to increase the adsorptivity of the organic compound. As another method for supporting polyaniline, an electrolytic polymerization method (Material Technology, vol. 15, No. 5, p. 165 (1997)) can also be applied.

The anode 3 and the cathode 4 are connected to a constant-voltage DC power supply 6 so as to be energized. When energizing, the voltage of the DC power supply 6 is not particularly limited as long as it does not affect the performance of the electrode.
Or less, more preferably 5 V or less. Further, an electric control circuit for automatically inverting the voltage between the anode 3 and the cathode 4 at regular intervals for a fixed period of time may be provided for the purpose of removing dirt generated on the surface of the electrode during operation. The set time at that time is, for example, 5 minutes every 24 hours.

In the container 2, the anode portion 8 is formed by a partition 7 extending between the electrodes 3 and 4 and in parallel with the plate-like electrodes 3 and 4.
And the cathode portion 9 are divided into two sections. Part or all of the partition wall 7 is formed of the diaphragm 5 so that current flows between the anode 3 and the cathode 4. The diaphragm 5 is not particularly limited as long as an electric current flows between the anode 3 and the cathode 4, but an electronically insulating and porous film can be preferably used. Vinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), polyethylene, poval (PV
A), those using polyacetylene, cellulose and the like can be used. These base materials may be copolymerized in an appropriate ratio. Further, those obtained by chemically modifying the base material by adding an additive thereto are also preferably used. The installation position of the diaphragm 5 (partition 7) is located in front of the cathode 4, that is, between the anode 3 and the cathode 4, and the interval (distance) between the cathode 4 and the diaphragm 5 is not particularly limited, but a high current value can be obtained. As short as possible, it is preferable that the cathode 4 is in contact with the cathode 4 if the cathode 4 is porous such as graphite felt. Cathode 4
Is not porous, such as a graphite plate,
The distance is preferably set to 0.5 to 50 cm, more preferably 1 to 20 cm. Similarly, the anode 3 and the diaphragm 5
The distance (distance) is not particularly limited, but it is better to be as short as possible so as to obtain a high current value. If the anode 3 has a perforated shape such as a mesh, for example, the contact may be made. When the anode 3 is an electrode such as a flat plate that completely separates the flow of water, the distance is preferably 0.5 to 50 cm, more preferably 1 to 20 cm. The means for fixing the diaphragm 5 (the partition 7) is not particularly limited.
For example, as shown in the drawing, the bolt 10 and the nut 11 may be used for fixing. Further, the diaphragm 5 is connected to the anode section 8.
May be fixed to the side container 2 by fixing means such as screws, bolts and nuts.

At one end of the cathode portion 9 of the container 2, a water inlet 12 for the water to be treated is provided, and at the other end, an outlet 13 for the water to be treated is provided. Plankton, cysts, bacteria, viruses, etc. contained in the water to be treated continue to be damaged by treatment species such as hydrogen peroxide generated from the cathode 4 while the water to be treated introduced from 12 passes through the inside of the cathode portion 9. Are killed and processed,
This treated water is discharged from the discharge port 13.

A conductive substance is placed in the anode section 8,
As the conductive substance, an alkaline buffer, a solid electrolyte thereof, an aqueous alkali solution, an alkaline solid electrolyte, or the like is preferably used. Specifically, for the alkaline buffer, for example, boric acid + potassium chloride + sodium hydroxide, glycine + sodium hydroxide, borax + hydrochloric acid, borax + sodium hydroxide, borax with a pH set to 7 or more + Sodium carbonate, hydrochloric acid + sodium carbonate, disodium hydrogen phosphate + sodium hydroxide, dimethylglycine sodium + hydrochloric acid, borax + potassium chloride + sodium carbonate, sodium carbonate + sodium hydrogen carbonate, disodium hydrogen phosphate + hydrogen phosphate Examples include, but are not limited to, dipotassium. The concentration of these electrolytes is not particularly limited as long as there is no deposition by long-term energization, but is preferably set to 30% by mass or less. Also,
The buffer may be gelled by adding a gelling agent and used as a solid electrolyte. On the other hand, for the alkaline aqueous solution,
What dissolved the basic inorganic compound, such as sodium hydroxide and potassium hydroxide, in water can be used. The concentration of these basic inorganic compounds is not particularly limited as long as no precipitation is caused by long-term energization, but is set to 0.1% by mass to 50% by mass,
Preferably it is set to 1% by mass to 40% by mass. Also,
Since the alkaline aqueous solution is very harmful to the human body if it leaks out of the anode part due to some obstacle, a gelling agent may be added to form a sol-gel to lower the fluidity.

When a solution (liquid) such as an alkaline buffer solution or an alkaline aqueous solution is used as the conductive substance, FIG.
As shown in (1), a circulating means for storing a predetermined amount of the solution in the liquid storage tank 18 and guiding and circulating a part of the solution in the liquid storage tank 18 to the anode unit 8 may be provided. Specifically, a liquid inlet 14 is provided at one end of the anode section 8 of the container 2, and a liquid outlet 15 is provided at the other end. These mouths 14, 15
Then, conduits 16 and 17 connected to the liquid storage tank 18 are connected to each other, and a circulation pump 19 is interposed in one of the conduits 16 and 17 (the conduit 16 in the illustrated example). With this configuration, when a conductive substance, for example, an alkaline aqueous solution is neutralized, it is possible to easily replace the conductive substance with a new conductive substance.

Further, the water to be treated, for example, seawater, may be introduced into the cathode portion 9 as it is, and as shown in FIG. 3, in order to efficiently generate hydrogen peroxide in the cathode portion 9. Alternatively, an oxygen-containing gas mixing means 22 for introducing the oxygen-containing gas after mixing may be provided. Mixing of the water to be treated and the oxygen-containing gas may be performed by any means as long as the mixing can be performed.For example, a mixer such as an ejector can be used. Bubbling or spraying of the water to be treated in the form of a mist may be used for mixing. The mixing ratio between the water to be treated and the oxygen-containing gas can be arbitrarily determined. However, when the cathode is formed porous, the mixing ratio of the oxygen-containing gas and the water to be treated (oxygen-containing gas liter / liter) is considered from the viewpoints of the dispersion of the water to be treated and the smooth supply and drainage. The water to be treated (ml) is preferably, for example, 0.1 to 10. In addition, from the viewpoint that electrolysis can be performed with high current efficiency even at a high current density, for example, when the water to be treated is atomized, the average droplet meter of the atomized water to be treated is in the range of 1 to 100 μm. Is preferred. Specific examples of the oxygen-containing gas include oxygen, air, and PSA oxygen. As the oxygen source, liquefied oxygen has been generally used. It is preferable that the oxygen-containing gas does not substantially contain carbon dioxide because it can be operated with high current efficiency for a long time. The oxygen-containing gas substantially free of carbon dioxide can be adjusted, for example, by passing the raw material gas through an aqueous alkali solution. The oxygen-containing gas is preferably at a pressure higher than the atmospheric pressure from the viewpoint that a sufficient amount of the oxygen-containing gas can be mixed with the water to be treated.

Next, a description will be given of a case where the water to be treated such as seawater or a mixed water containing seawater is treated using the seawater purifying apparatus 1, but the present invention is not limited to these.

A first example is a case where seawater (treated water) treated by the seawater purifying apparatus is temporarily stored in a storage means such as a tank and put to practical use. In particular,
The seawater purifying apparatus (seawater purifying apparatus shown in FIGS. 1 and 2) 1 is interposed between a seawater suction pump 20 and a seawater tank 21 as shown in FIG. While applying the voltage, the seawater suction pump 20 is driven. Part of the seawater is sucked by the seawater suction pump 20 and the cathode 9
Guided inside. At this time, the purifying apparatus 1 uses a liquid such as an alkaline buffer solution or an aqueous alkaline solution as the conductive substance.
A part of the conductive material inside is guided to the anode part 8. By energizing,
A treated species such as hydrogen peroxide is generated from the cathode 4, and the treated species continuously damages and destroys plankton including harmful plankton contained in seawater, cysts, bacteria and viruses, and treats seawater. Is done. The treated seawater (treated water) is discharged from the outlet 13 and reaches the seawater tank 21. In this case, since the cathode 4 and the anode 3 are separated by the diaphragm 5, generation of an organic acid such as hypozinc acid from the electrode surface can be prevented. In addition, since the processing species generated from the cathode 4 is not decomposed at the anode 3,
Seawater treatment can be performed more stably.

Therefore, according to the present invention, a treatment species is generated from the cathode 4, the water to be treated is treated by the treatment species, and the cathode 4 and the anode 3 are separated by the diaphragm 5 to prevent the generation of organic acids. A large amount of water to be treated can be safely treated by a method without any risk of secondary contamination of the water to be treated, and the cost is high.

The second example is a case in which seawater or the like that needs to be treated before being discharged because it is once stored in a storage means such as a tank is treated. The seawater purifier 1 of the present invention is interposed between a discharge pump (not shown) of the tank and a drain pipe (not shown), and while applying a direct current to the cathode 4 and the anode 3, the seawater is drained. Do. Even in this case, as in the first example, plankton and cysts contained in seawater are continuously damaged and die, and the treated seawater is discharged. A large amount of seawater can be safely treated with no method at all.

In the third example, the water to be treated such as seawater stored in a tank or the like is cyclically treated, and the seawater or the like in the tank is constantly removed without taking in or discharging new seawater. Keep it in the best condition. Specifically, the seawater purifying apparatus 1 is installed so that the seawater taken into the tank 21 can be circulated, and the seawater is circulated while applying a direct current to the cathode 4 and the anode 3. Even in this case, as in the first example, plankton, cysts, and the like contained in seawater are continuously damaged and die, and the treated seawater is returned to the tank. A large amount of seawater can be safely treated by a method without any wastewater.

In the embodiment of the present invention, the case where one seawater purifying apparatus 1 of the present invention is provided for processing has been described. However, a plurality of the seawater purifying apparatuses 1 of the present invention are connected in series to be treated. The treatment of the treated water may be performed. In this way, by connecting a plurality of units in series, it becomes possible to more reliably treat the water to be treated. The flow direction of the fluid in the anode section 8 and the flow direction of the fluid in the cathode section 9 may be either the same direction or the opposite direction, and is not particularly limited.

FIG. 5 is a view showing another example of the container of the seawater purification apparatus of the present invention. The difference from the container 2 is that the outer shape of the container 24 and the arrangement of the anode 25 and the cathode 26 are different. It is. That is, the container 24 is formed in a cylindrical shape,
A cylindrical inner tube 27 having a small diameter is provided coaxially in the container 24, and the container 24 is formed in a double tube structure. A cylindrical anode 28 is provided on the axis of the container 24 on the same axis. On the inner peripheral surface of the container 24, which is an outer tube, a plurality of cathodes 29 are provided in the illustrated example at predetermined intervals in the circumferential direction. Anode 28 and cathode 2
An opening 30 is provided in the inner tube 27 at a position connecting the inner tube 9 and the inner tube 9. That is, four openings 30 are provided at intervals of 90 ° in the circumferential direction of the inner tube 27, and four cathodes 29 are provided at intervals of 90 ° on the inner peripheral surface of the container 2 radially outward of the opening 30. It will be. A cylindrical diaphragm 31 is provided on the inner peripheral surface of the inner tube 27, and the inside of the inner tube 27 is formed as the anode part 25, and the inside of the container 24 outside the inner tube 27 is formed as the cathode part 26. The conductive material enters into 25 and the water to be treated enters into the cathode portion 26. The treated water inlet 12 and the treated water outlet 13 at one end of the cathode portion 26 are not particularly limited to one or two or more, respectively. It is preferable to provide them at predetermined intervals in the direction.

Even when the seawater purifying apparatus 1 is configured as described above, the same operation and effect as described above can be obtained. That is, a case where the water to be treated such as seawater or a mixed water containing seawater is treated before being put into a tank as in the first example will be described. The seawater purification apparatus 1 shown in FIG. As shown in the drawing, a seawater suction pump 20 and a seawater tank 21 are interposed between the seawater suction pump 20 and the seawater suction pump 20 while applying a direct current to the cathode 29 and the anode 28.
The seawater suction pump 20 and the circulation pump 19 are driven. As a result, plankton, cysts, bacteria, viruses, and the like contained in the seawater flowing in the cathode portion 26 are continuously damaged and killed by the treatment species such as hydrogen peroxide generated from the cathode 29, and the seawater is discharged. It is processed. The treated seawater (treated water) is discharged from the outlet 13 and reaches the seawater tank 21. In this case, since the cathode 4 and the anode 3 are separated by the diaphragm 5, generation of an organic acid such as hypozinc acid from the electrode surface can be prevented. Further, since the treatment species generated from the cathode 4 is not decomposed by the anode 3, the treatment of seawater can be performed more stably. Therefore, even if the container 24 is formed in a double-pipe structure, a treatment species is generated from the cathode 29, the treated water is treated by the treatment species, and the cathode 29 and the anode 28 are separated by the diaphragm 31 and the organic acid is separated. Since the generation of water is prevented, it is possible to safely treat a large amount of water to be treated by a method without any risk of secondary contamination of the water to be treated.

By arranging the cathode 29 on the inner peripheral surface of the container 24 and the anode 28 on the axis, the surface area of the cathode 29 is increased, the amount of treated species is increased, and the treatment of seawater can be performed more reliably. However, if the treatment of seawater can be sufficiently performed, the cathode may be arranged on the axis and the anode may be arranged on the inner peripheral surface of the container.

[0033]

EXAMPLES Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these.

(Example) A container 2 (width 300 m) made of polyvinyl chloride having a length of 1 m and having the shape shown in FIGS.
m, height 100 mm), five graphite plates EG-30X (manufactured by Nippon Carbon Co., Ltd., 200 mm × 80 mm) at intervals of 100 mm along the longitudinal direction of the container 2 and a titanium platinum plate (200 mm × 80 mm) Are attached at intervals of 100 mm along the longitudinal direction of the container 2, and a diaphragm 5 is provided at the center.
"Durapore membrane filter VVLP1425
0 "(manufactured by MILLIPORE). Five sets of the containers 2 of the seawater purification apparatus having such a configuration are connected in series, and the treated water inlet 12 of the cathode portion 9 of the endmost container 2 is connected.
A water pipe to be treated is connected to the container, and a storage tank 18 containing 30 L of a 1 M alkaline aqueous solution as a conductive substance and the anode section 8 are connected to the conduit 1.
6 and 17 were connected. Then, the graphite plate electrode of each electrode pair was connected to the cathode side, and the titanium platinum plate was connected to the anode side, and while applying 2.0 V DC to each electrode pair, the seawater suction pump 22 was operated to operate at 1 m / s. At speed, it passed through seawater containing harmful plankton and cysts. A part of the water thus continuously treated was collected, stored at 15 ° C. for one month, and observed with a microscope, but no plankton was generated.

(Comparative Example) Seawater without the above treatment was
When stored at 5 ° C. for one month, many planktons were generated and the seawater was colored reddish brown.

[0036]

In summary, according to the present invention, it is possible to safely treat a large amount of water to be treated by a method without any risk of secondary contamination.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a first example of a seawater purification apparatus of the present invention.

FIG. 2 is a sectional view of the seawater purifying apparatus of the present invention shown in FIG.

FIG. 3 is a configuration diagram showing an example of a usage form of the seawater purification device of the present invention.

FIG. 4 is a configuration diagram showing an example of processing ballast water with the seawater purification device of the present invention.

FIG. 5 is a schematic sectional view showing another example of the container of the seawater purification device of the present invention.

6 is a configuration diagram illustrating an example of processing ballast water by the seawater purification device illustrated in FIG. 5;

[Explanation of symbols]

 1 Seawater purification device 2 Container 3 Anode 4 Cathode 5 Diaphragm 6 Power supply 8 Anode unit 9 Cathode unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 1/50 550 C02F 1/50 550D 560 560F (72) Inventor Minoru Minoda Chidoricho, Naka-ku, Yokohama-shi, Kanagawa No. 8 Nishiishi Mitsui Co., Ltd. Central Research Laboratory F term (reference) 4D061 DA04 DB01 EA04 EB05 EB12 EB17 EB19 EB28 EB29 EB30 EB31 ED12 ED20

Claims (4)

[Claims] 1. A container is partitioned into a cathode part and an anode part by a diaphragm, a conductive substance is put in the anode part, and water to be treated such as seawater or a mixed water containing seawater is put in the cathode part. A treatment species is generated in the cathode part by applying a voltage between the anode in the part and the cathode in the cathode part, and the plankton, plankton cysts, bacteria, and viruses in the treatment water are killed by this treatment species to treat the treatment water. A method for purifying seawater. 2. A container provided with a cathode and an anode to be energized is partitioned into a cathode portion into which seawater or a mixed water containing seawater enters, and an anode portion into which a conductive substance enters. In part, a diaphragm is disposed so that current flows between the electrodes, and the cathode treats the treated water by killing plankton, plankton cysts, bacteria, and viruses in the treated water by energization. An apparatus for purifying seawater, which is a processing electrode for generating a processing species. 3. The conductive substance is an alkaline buffer solution or an alkaline aqueous solution, a storage tank for storing the conductive substance is provided, and a part of the conductive substance of the storage tank is transferred to the anode part. 3. The seawater purifying apparatus according to claim 2, further comprising a circulating means for returning to the liquid storage tank after the supply. 4. The seawater purifying apparatus according to claim 2, further comprising an oxygen-containing gas mixing means for mixing an oxygen-containing gas into the water to be treated to the cathode section.