JP2001000974A - Treatment of ballast water and ship - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the pollution of soil or seawater caused by treating ballast water by supplying ballast water for keeping the stability of a ship to the surface of the sea to a fixed bed type electrode electrolytic cell to treatmicroorganisms in ballast water. SOLUTION: A ballast tank 301 for housing ballast water 303 is disposed in the ship body 300 of a ship. The ballast water 303 is introduced into or discharged from the ballast tank 301 by the action of a pump 306 through a piping 320 and treated in the fixed bed type electrode electrolytic tank 304 disposed on the way of the piping 320 to kill microorganisms in the ballast water. The treated ballast water is supplied to the ballast tank 301. When the ship is loaded with ballast water 303 to navigate and arrives at a destination, a cargo is housed in the cargo storehouse 302 of the ship and, at this time, the ballast water 303 is discharged out of the ship through the piping 32 by the action of the pump 306. At this time, microorganisms in the ballast water 303 are killed by the fixed bed type electrode electrolytic cell 304 disposed in the route of the piping 320.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of treating ballast water for preventing ballast water from being discarded in seawater for maintaining the stability of the ship against the sea surface and contaminating the seawater with microorganisms.

[0002]

2. Description of the Related Art Normally, seawater is used as ballast water. However, seawater from a port at the landing site is used in order to prevent a ship from unloading cargo, to reduce the weight of the ship and to float from the sea surface. After landing, a ship loaded with a large amount of ballast water will have its cargo unloaded when it reaches its destination, but the weight of the unloaded cargo will prevent the hull from diving into the seawater. To discharge the ballast water from the ship.

[0003]

During the navigation of the ship to the destination, microorganisms inhabit the seawater, which repeats breeding while the ship is navigating, and the ballast water is polluted. Will be. Discarding such contaminated ballast water at the destination as it is is extremely problematic because it will contaminate the soil and seawater at the destination and destroy the ecosystem.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a method and a ship for preventing soil and seawater from being contaminated by ballast water disposal.

[0005]

[Means for Solving the Problems] (1) Ballast water characterized by supplying ballast water for maintaining the stability of a ship to the sea surface to a fixed-bed electrode electrolytic cell and treating microorganisms in the ballast water. Processing method. (2) The method for treating ballast water according to (1), wherein the ballast water is treated in the fixed-bed electrode electrolytic cell in a ship. (3) The method for treating ballast water according to (2), wherein the ballast water is treated in the fixed-bed-type electrode electrolytic cell while the ship is sailing. (4) The method for treating ballast water according to (1), wherein the ballast water is treated outside the vessel in the fixed-bed electrode electrolytic cell. (5) A ship having a fixed-bed electrode electrolytic cell for treating microorganisms in ballast water for maintaining stability against the sea surface.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The present invention is characterized in that ballast water for maintaining stability on the sea surface of a ship is supplied to a fixed-bed electrode electrolytic cell to treat microorganisms in ballast water. The microorganism of the present invention includes bacteria (bacteria), plankton, fungi,
Filamentous fungi (fungi), Escherichia coli, yeast, deformed fungi, unicellular algae,
Protozoa, viruses and the like are included. When ballast water is supplied to the fixed-bed type electrode electrolytic cell, microorganisms in the ballast water contact the anode and cathode of the fixed-bed type electrode of the electrolytic cell by liquid flow, and receive high-potential energy supply on their surface to generate strong power. An oxidation-reduction reaction occurs in the cells of the microorganism, and its activity is weakened or the microorganism itself is killed and sterilized. The fixed bed electrode electrolyzer of the present invention includes a fixed bed electrode that causes a polarization phenomenon, and a power supply electrode that polarizes the fixed bed electrode.
As the fixed-bed electrode, a porous material through which the ballast water can pass, for example, felt, woven, activated carbon having a shape such as a porous block, graphite, carbon-based material such as carbon fiber, or Metal materials having the same shape, such as nickel, copper, stainless steel, iron, titanium, etc., and materials coated with a noble metal are used, and the power supply electrode is a flat plate, expanded mesh, or perforated. A material made of a perforated plate such as a plate is used. When using a carbon-based material such as activated carbon, graphite, and carbon fiber as the fixed bed electrode and treating the water to be treated while generating oxygen gas from the anode, the fixed bed electrode is oxidized by oxygen gas. May dissolve as carbon dioxide. In order to prevent this, a porous material usually used as an insoluble metal electrode is formed 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 type electrode which is positively polarized. The materials may be placed in contact so that oxygen evolution occurs primarily on the porous material.

[0007] It is preferable that the fixed-bed type electrode has a predetermined average opening diameter. If the fixed-bed type electrode has a large opening diameter, microorganisms in ballast water can easily pass through the electrolytic cell without contacting the electrode, so that the killing effect of the microorganisms is reduced. Conversely, if the opening diameter is too small, the ballast water cannot flow through the fixed-bed electrode, causing an increase in the electrolytic voltage and a pressure loss of the liquid flow in the electrolytic cell. In particular, when a carbonaceous fixed bed electrode is used, it is desirable that the average pore diameter is 25 to 125 μm. Next, preferred examples of the electrolytic cell that can be used in the present invention will be described with reference to the accompanying drawings, but the electrolytic cell that can be used in the present invention is not limited to this electrolytic cell.

FIG. 1 is a schematic longitudinal sectional view showing a first example of a monopolar fixed-bed type electrode electrolytic cell which can be used as an electrolytic cell in the method of the present invention.

A lower portion of a cylindrical electrolytic cell body 3 having a ballast water supply port 1 in the center of the bottom plate and a ballast water outlet 2 in the center of the top plate is formed of a carbonaceous material, a metal sintered body or the like. The small cylindrical porous fixed bed type cathode 4 to be formed is accommodated so as to form only a small gap with the inner wall of the main body 3 so that liquid flow does not substantially occur. An anode 5 made of, for example, a mesh-shaped platinum group metal oxide-coated titanium material is accommodated through the gap. The electrolytic cell main body 3 is preferably formed of an electrically insulating material that can withstand long-term use or re-use. Particularly, synthetic resins such as polyepichlorohydrin, polyvinyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, and polyvinyl chloride Ethylene, phenol-formaldehyde resin, polyacrylonitrile resin and the like can be preferably used.

When the microorganisms in the ballast water pass from the ballast water supply port 1 to the ballast water outlet 2, they contact the porous fixed-bed cathode 4 and die.

FIG. 2 is a schematic vertical sectional view showing an example of a bipolar electrode (one electrode is polarized into an anode and a cathode) fixed-bed type electrode electrolytic cell which can be used as an electrolytic cell in the method of the present invention. is there.

A meshed power supply anode terminal 93 and a power supply cathode terminal are provided near the upper end and the lower end of a cylindrical electrolytic cell main body 92 having a flange 91 on the upper and lower sides, respectively.
94 are provided. In the illustrated example, a plurality of sponge-like fixed beds 95 are laminated between the electrode terminals 93 and 94, and between the fixed bed 95 and between the fixed bed 95 and the electrode terminals 93 and 94. Are sandwiched between four mesh-shaped diaphragms or spacers 96. Each fixed bed 95 is in close contact with the inner wall of the electrolytic cell main body 92 and does not pass through the inside of the fixed bed 95, so that the leakage flow of the water to be treated flowing between the fixed bed 95 and the side wall of the electrolytic cell main body 92 is minimized. Are located in

When power is supplied to the electrolytic cell having such a configuration while supplying ballast water from below as indicated by an arrow, when the fixed bed 95 is polarized, the lower surface becomes positive and the upper surface becomes negative as shown in the figure. A porous cathode is formed on the upper surface of each fixed bed 95, and a porous anode is formed on the lower surface, and the microorganisms in the ballast water are killed by contacting them. FIG. 3 shows another example of a bipolar fixed-bed type electrode electrolytic cell which can be used in the method of the present invention. The electrolytic cell is a side of the fixed bed 95 of the electrolytic cell of FIG. In other words, the mesh-shaped insoluble metal electrode 97
Are provided in close contact with each other, and the other members are the same as those in FIG. The fixed bed 95 to which the DC voltage is applied has the largest polarization at both ends, and when gas is generated, gas is likely to be generated at both ends. Therefore, the feeding cathode of the fixed bed 95 which is the most strongly anodic polarized, that is, generates the most intense oxygen gas
At the end toward 94, the oxidation reaction and the dissolution reaction of the electrode substrate occur fastest and violently. As shown in the figure, if an insoluble metal electrode 97 is installed in this portion, most of the oxygen gas is removed from the insoluble metal electrode 97 because the overvoltage of oxygen generation of the insoluble metal electrode 97 is lower than that of the carbon-based material forming the fixed bed 95. electrode
Since the fixed bed 95 is hardly brought into contact with the oxygen gas and is generated from 97, the dissolution of the fixed bed 95 is effectively suppressed. Further, the microorganisms in the ballast water supplied to the electrolytic cell 92 are treated and killed in the same manner as in the second case.

The electrolytic cell shown in FIG. 4 is a modification of the electrolytic cell of FIG. 2 and is provided with a filter. The same members as those of the electrolytic cell shown in FIG. The description is omitted.

On the upper flange 91 of the electrolytic cell body 92,
A lid 212 having an upwardly-facing cylinder 211 formed in the center is mounted thereon, and a flange at the upper end of the cylinder 211 and the treated water discharge pipe 21 are provided.
A filter 214 is sandwiched between the flanges at the lower end of the filter 3. Reference numeral 215 denotes a bottom plate in which a treated water supply pipe 216 is formed downward on the center lower surface. When current is supplied to the electrolytic cell having such a configuration while supplying ballast water from below as indicated by an arrow, the fixed beds 95 are polarized such that the lower surface is positive and the upper surface is negative, as shown in the figure. A potential is generated between the inside and the fixed bed 95, and the ballast water flowing through the electrolytic cell contacts the fixed bed 95 having this potential to treat microorganisms contained therein, and the electrolytic cell body 92 treated water discharge pipes 213
Taken out of Solid impurities such as dead microorganisms generated by this treatment are filtered when passing through the filter 214, so that solid impurities such as dead microorganisms cannot be taken out of the electrolytic cell.

FIG. 5 is a diagram showing a method for killing microorganisms in ballast water actually used in a ship.

A ballast tank 301 for storing ballast water 303 is provided in the hull 300 of the ship. The ballast water 303 is put into the ballast tank 301 (in the direction of the arrow X ′) or discharged (in the direction of the arrow X) by the action of the pump 306 through the pipe 320. A valve 305 is provided to prevent the ballast water from flowing except when the pump 306 is operating.

First, ballast water is supplied to a ballast tank 301.
Before being supplied to the pipe, the mixture is treated in a fixed-bed type electrode electrolytic cell 304 provided in the middle of the pipe 320 to kill microorganisms. Then, after being processed in the fixed-bed type electrode electrolytic cell 304, it is supplied to the ballast tank 301.

Further, when the ship loads the ballast water 303, sails, and arrives at the destination, the luggage is stored in the luggage storage 302. At this time, the ballast water 303 is pumped by the pump 306.
Is discharged outside through the pipe 320. At this time, the fixed-bed type electrode electrolytic cell 3 provided in the path of the pipe 320
04 kills microorganisms in ballast water.

In the above example, the fixed-bed type electrode electrolytic cell 304
The ballast water 303 is provided on a part of the piping 320 connecting the ballast tank 301 and the outboard for passage to the outside of the ballast water 303, but is not limited thereto. A fixed-bed type electrode electrolytic cell 304 is prepared in advance, so that the ballast water treated to kill microorganisms is introduced into the ship, or the microorganisms in the ballast water discharged outboard are killed. It may be.

Further, the microorganisms in the ballast water may be killed during the navigation of the ship. For example, a pipe 321 for circulating the ballast water 303 connected to the ballast tank 301 is provided, and the ballast water 303 is circulated by the action of the pump 309 (see arrows Y and Y ') and provided in the middle of the path of the pipe 321. The treatment may be performed in the fixed bed type electrode electrolytic cell 307 provided. Note that a valve 308 is provided to prevent the ballast water 303 from flowing back and forth in the pipe 321 except during circulation by the pump.

In the above description, the fixed-bed type electrode electrolyzers 304, 3
1 to 4 are used as 07, but the present invention is not limited to these.

[0023]

According to the present invention, soil and seawater pollution due to ballast water disposal can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an example of a monopolar fixed-bed electrode electrolytic cell that can be used as an electrolytic cell in the method of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing a first example of a bipolar fixed-bed electrode electrolytic cell that can be used as an electrolytic cell in the method of the present invention.

FIG. 3 is a schematic longitudinal sectional view showing a second example.

FIG. 4 is a schematic cross-sectional view showing a third example.

FIG. 5 is a diagram showing a method for killing microorganisms in ballast water.

Claims (5)

[Claims] 1. A method for treating ballast water, comprising supplying ballast water for maintaining stability to the sea surface of a ship to a fixed-bed electrode electrolytic cell and treating microorganisms in the ballast water. 2. The method for treating ballast water according to claim 1, wherein the ballast water is treated in the fixed-bed electrode electrolytic cell in a ship. 3. The fixed ball electrode electrolyzer according to claim 2, wherein the ballast water is treated in the fixed-bed type electrode electrolytic cell during navigation of a ship.
Ballast water treatment method. 4. The method for treating ballast water according to claim 1, wherein the ballast water is treated outside the vessel in the fixed-bed electrode electrolytic cell. 5. A ship having a fixed-bed electrode electrolytic cell for treating microorganisms in ballast water for maintaining stability to the sea surface.