JP2013126622A - System for treating ballast water of ship, and apparatus and method for treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for treating ballast water of a ship that can efficiently remove, eliminate, or deactivate microorganism from or in ballast water loaded in a ship.SOLUTION: The system for treating ballast water of a ship includes: a first water treatment device for treating sea water with a first filtration unit that filters sea water through a filter; a storage step for storing the sea water passed through the first water treatment device in a storage tank; and a second water treatment device for treating the sea water passed through the storage step. It is preferable that the filtration units are a rotating filter filtration device which is cylindrically disposed, and uses a filter having a pleat shape bent in a cylindrical radial direction.

Description

  The present invention relates to a treatment system for ballast water stored for stability during navigation of a ship, and more particularly to advanced treatment of ballast water discharged in other sea areas after being mounted on a ship. .

  In recent years, the treatment of ballast water loaded on ships has become a problem. Ballast water is seawater loaded on a ship for safe navigation even in an empty state. Ballast water is taken from the nearby ocean at the departure of the voyage and drained to the nearby ocean at the arrival point. That is, ballast water consisting of seawater from the departure point is drained at the arrival point.For example, when an oil tanker departing from Japan sails to the Middle East, such as Kuwait, an oil-producing oil country, It is loaded as ballast water and drained offshore in the Middle East. When ballast water is discharged into a sea area different from the sea area where water is taken, organisms in the seawater are moved to sea areas that are not originally habitats, which greatly affects the marine ecosystem.

  For this reason, various methods for purifying ballast water to remove or kill or inactivate microorganisms have been studied. For example, Patent Document 1 discloses a method for sterilizing underwater organisms by heating seawater, Patent Document 2 discloses a method using steam and a method using ultraviolet irradiation, and other electrical methods such as voltage application and shock waves. In addition, a method of introducing a chemical such as sodium hypochlorite has been proposed. In addition, a method using filtration as a pre-stage of the killing treatment or for the purpose of removing relatively large microorganisms has been studied. For example, Patent Document 3 describes a method for producing ballast water using a filtration membrane. Yes.

  In addition, the inventors of the present application are examining the treatment of such ballast water, and disclose a filtration device using a rotating cylindrical pleated filter as in Patent Document 4. The ballast water treatment device is arranged in a cylinder so as to surround an axis, and is provided with a filter rotatably provided around the axis, and a water to be treated which discharges the water to be treated toward the outer peripheral surface of the filter, A case having an outer cylindrical portion provided around the filter and provided with a nozzle opening of the water nozzle to be treated, and the filtered water that has passed through the filter is led out from the inside of the cylinder of the filter to the outside of the case A ship ballast water treatment apparatus comprising: a filtered water flow path for discharging water; and a discharge flow path for discharging discharged water not filtered by the filter to the outside of the case. With this configuration, filtration is performed while continuously moving the filter surface while rotating the filter by ejecting water to be treated from the outside of the cylindrically arranged filter toward the filter outer peripheral surface. As a result, it is possible to continue filtration while removing clogging of the filter, and foreign matter removal can be performed more efficiently than a flat filter having the same membrane area.

Japanese Patent No. 3660984 Japanese Patent No. 4261955 JP 2006-728 A JP 2011-194396 A

Conventional ballast water treatments such as Patent Documents 1 to 3 have their respective disadvantages, and the inventors of the present application have developed a treatment apparatus such as Patent Document 4 as a solution. However, the demand for environmental impact of ballast water is increasing, and it is expected that more advanced treatment will be required in the future. For example, according to the standards of the International Maritime Organization (IMO) that is currently being enacted, as aquatic organisms contained in ballast water, the number of organisms with a minimum size of 50 μm or more is less than 10 / m ³ , the minimum size is less than 50 μm, 10 μm Regulations such as less than 10 organisms / mL are being studied. Furthermore, as a stricter standard, for example, the development of a standard of 10 to 1000 times the IMO such as a minimum size of less than 50 μm, 10 μm or more of organisms / less than 100 ml is under consideration. Under such circumstances, the conventional ballast water treatment apparatus cannot perform sufficient treatment satisfying the standard, and a further advanced treatment system is required. Increasing the intensity of ultraviolet rays, for example, for the advancement of sterilization treatment has disadvantages and limitations such as an increase in power consumption and an increase in the size of the ultraviolet irradiation device. Increases are a problem. An object of the present invention is to provide a treatment system capable of treating ballast water with less aquatic organisms in the ballast water.

  The inventors of the present application have arrived at the present invention as a result of intensive studies on means that can be installed on a ship and that can efficiently purify ballast water.

  The invention of the present application has undergone the first water treatment means for treating seawater by the first filtration means for performing filtration using a filter, the storage step for storing seawater that has passed through the first water treatment means in a storage tank, and the storage step. A marine ballast water treatment system having second water treatment means for treating seawater with a second filtration means.

  The inventors of the present application have conceived that it is possible to drastically reduce the amount of aquatic organisms in ballast water by performing filtration again after filtration and storage. Conventionally, when a seawater is loaded on a ship, it is generally performed by a ballast water treatment device, and when discharged after voyage, it is generally discharged to the ocean as it is. However, it has been found that the amount of aquatic organisms in the ballast water can be drastically reduced by performing filtration again before such discharge.

  Such an effect is that each of the first filtering means and the second filtering means is arranged in a cylinder so as to surround an axis, is provided so as to be rotatable around the axis, and is bent in the radial direction of the cylinder. A filter having a pleat shape, a water nozzle to be treated for flowing out water to be treated on an outer peripheral portion of the filter, and an outer cylinder portion provided so as to surround the filter and having a nozzle port of the water to be treated inside. A case having a filtered water flow path through which the filtered water that has passed through the filter is led out from the inside of the cylinder of the filter to the outside of the case, and a discharge flow path for discharging the discharged water that has not been filtered by the filter to the outside of the case And a ballast water treatment system for ships, which is a rotary filter filtration device provided with an electric motor for rotating the filter.

  This is because such a filtering device is excellent in processing efficiency and has a high aquatic organism removal effect, and therefore can perform processing effectively and efficiently even when filtering twice on a ship. In other words, in such a configuration, filtration is performed while continuously moving the filter surface by sending the water to be treated to the outer periphery of the filter arranged in a cylinder and rotating. Further, it is possible to continue filtration while removing the clogging of the filter, and it is possible to remove foreign substances more efficiently than a flat filter having the same membrane area. The pleated shape refers to a shape in which peaks and valleys are repeated by making a large number of creases on a filter surface arranged in a cylindrical shape. By adopting a pleated shape, the area of the membrane can be effectively increased. In particular, an apparatus used on a ship with a large restriction on the installation location is preferable for reducing the installation area of the entire apparatus.

Here, the first water treatment means and / or the second water treatment means further performs a killing process using an ultraviolet irradiation lamp having an irradiation amount of 50 mJ / cm ² or more provided in the flow path of the filtered seawater. It is preferable to include. This is because killing of aquatic organisms such as plankton is necessary in addition to filtration, and in particular, efficient processing can be performed with equipment that is easy to process with an ultraviolet lamp.

  The filter is preferably a filter capable of removing 99% or more of plankton in seawater of 30 μm or more. Such a filter is necessary in order to satisfy a standard defined by IMO or the like.

  The storage step may be a step of storing seawater in a tank blocked from sunlight for one day or more. In general, since the storage process is storage in an onboard tank during vessel navigation, the storage period is often longer. By being shielded from sunlight, the growth of phytoplankton in seawater is suppressed, and zooplankton decreases due to the decrease in phytoplankton. Although it is sufficient if there is at least 1 day or more of storage, storage of 5 days or more is preferable.

  Furthermore, the first filtering means and the second filtering means may be the same rotary filter filtering device. By using the same apparatus, a great profit can be obtained in terms of equipment cost, space efficiency on board a ship, and equipment operation efficiency. In order to use the same filtration device twice at the time of loading and discharging seawater, the first water treatment means sends seawater taken from the outside as treated water to the treated water nozzle and supplies the filtered water to the treated water nozzle. In the first pipe configured to send to the storage tank and the second water treatment means, seawater from the storage tank is sent to the treated water nozzle as treated water, and the filtered water is discharged to the outside. It is preferable that the second pipe configured as described above is configured to be selectable and switchable between the first pipe and the second pipe.

  As described above, the preferred embodiment of the ballast water treatment device used in the marine ballast water treatment system according to the present invention is arranged in a cylinder so as to surround the axis, and is provided to be rotatable around the axis. A filter having a pleat shape bent in the radial direction of the cylinder, a treated water nozzle for flowing the treated water to the outer periphery of the filter, and a nozzle port of the treated water nozzle provided to surround the filter A case having an outer cylindrical portion provided inside, a filtered water passage for leading filtered water that has passed through the filter from the inside of the cylinder of the filter to the outside of the case, and drained water that has not been filtered by the filter. A rotary filter filtration device provided with an electric motor for rotating the filter, and a drainage flow path for discharging the filter to the outside, and installed in the flow path of the filtrate water. An ultraviolet irradiation device having an ultraviolet lamp, a storage pipe for guiding the filtered water to a storage tank, seawater introduced from the outside, and seawater discharged from the storage tank to be treated water for the rotary filter A ship ballast water treatment apparatus having a supply pipe that can be supplied.

  The present invention also provides a method for treating ballast water that is provided in a vessel as ballast water using seawater in the first sea area near the departure point and loaded on a tank, and discharged outside the ship in the second sea area near the arrival point. When the seawater is ballast water in the first sea area, the seawater is filtered using a filter, and when the ballast water is discharged in the second sea area, it is filtered again using a filter. Provided is a ballast water treatment method for marine vessels characterized by the treatment.

  According to the above invention, it is possible to efficiently remove, kill, and inactivate turbidity and microorganisms with respect to the ballast water discharged from the ship or loaded into the ship. A treatment system capable of treating ballast water with less organisms can be provided.

It is explanatory drawing which showed typically the whole structure of the processing system for ballast water for ships concerning this invention. It is a block diagram which shows the structural example of the processing apparatus for ballast water for ships concerning this invention. It is a longitudinal cross-sectional schematic diagram explaining the structural example of the rotary filter filtration apparatus as a preferable aspect of the filtration means in this invention. It is a schematic diagram which shows the AA cross section in FIG. It is a perspective schematic diagram explaining the typical structure of the pleated filter used suitably for this invention. It is a figure explaining the basic flow of the processing method of the ballast water of this invention.

  The apparatus structure and processing method of the processing system for ballast water for ships concerning the present invention are explained with reference to drawings. In addition, this invention is not limited to this, It is shown by the claim, and it is intended that all the changes within the meaning and range equivalent to a claim are included.

  FIG. 1 is an explanatory diagram schematically showing the overall configuration of a marine ballast water treatment system according to the present invention. This system removes turbidity and microorganisms, kills, and inactivates seawater taken from the ocean 2 by filtering with the ballast water treatment device 10 when the ballast water is loaded on the tank 11 provided in the ship 1. To do. Further, when the ballast water stored in the tank 11 for a certain period is discharged to the ocean 2, processing such as filtration is performed again by the processing device 10.

  FIG. 2 shows a configuration example of the processing apparatus 10 described above. Here, as a preferred embodiment, a description will be given of a configuration in which processing is performed using the same apparatus both when storing seawater from the ocean as ballast water in a tank and when discharging ballast water from the tank. However, it is also possible to prepare separate processing apparatuses for these two processes.

  In FIG. 2, seawater taken from the ocean through a pipe 31 is supplied by the pump 21 to the filter device 12 that is a filtering means through the pipe switching unit 14 and the pipe 33. Seawater filtered in the filter device is sent to the ultraviolet irradiation device 13 as a killing means through the pipe 34. Further, the discharged water that has not been filtered in the filter device 12 is led out of the device through the pipe 38. The seawater irradiated with ultraviolet rays is sent to the tank 11 through the pipe 35, the pipe switching unit 15, and the pipe 37. Thus, in the 1st water treatment means which takes in seawater, the pipe switching part 14 and the pipe switching part 15 are switched so that seawater may flow as mentioned above. Here, in the first water treatment means, the killing means is not limited to the ultraviolet irradiation device 13, and the ultraviolet irradiation device 13 is omitted, and chemical treatment is performed on the ballast water stored in the tank. It is also possible to use other means.

  Next, the ballast water that has passed through the first water treatment means is stored in the tank for a certain period. In general, this storage is performed during the voyage of the ship, and the second water treatment means is performed when ballast water is discharged at the port of call of the ship. The flow of processing in the second water treatment means is as follows. Ballast water stored in the tank 11 is sent from the pipe 32 to the pipe switching unit 14 by the pump 22. Here, the pipe switching unit 14 is switched to send the water from the pump 22 to the pipe 33 as the water to be treated, contrary to the first water treatment means. Ballast water sent from the pipe 33 to the filter device 12 as the filtering means is filtered and sent to the pipe 35 through the pipe 34 as filtered water and the ultraviolet irradiation device 13 as the killing means. Here, also in the second water treatment means, the killing step by the ultraviolet irradiation device 13 is not essential. In the second water treatment means, the pipe switching unit 15 is switched so as to send filtered water from the pipe 36 to the outside.

  FIG. 3 and FIG. 4 are schematic diagrams illustrating a configuration example of a rotary filter filtration device as a preferred embodiment of the filtration means. 3 shows a longitudinal section of the rotary filter filtration device, and FIG. 4 shows an AA transverse section in FIG. The cylindrical filter 101 is disposed so as to surround an axis serving as a rotation center, and is rotatably attached around a central pipe (pipe does not rotate) disposed at the center. The filter is preferably a pleated filter that is creased so as to repeat peaks and valleys in the radial direction of the cylinder. The upper and lower surfaces of the filter are closed watertight. The rotatable mounting structure also needs to be a watertight structure, but a known structure is used without any particular limitation. A case 103 is provided so as to cover the entire filter. The case 103 includes an outer cylinder part 131, a lid part 132, and a bottom part 133, and a discharge pipe 108 is provided on the bottom part 133. A treated water pipe 106 and a treated water nozzle 102 are provided in order to introduce seawater as treated water into the case 103. The to-be-treated water nozzle 102 extends from the to-be-treated water pipe 106 so that the nozzle opening 121 is provided in the outer cylinder part 131 of the case 103, and the to-be-treated water flows out toward the outer peripheral surface of the filter. Has been.

  In the case of this example, the water to be treated ejected from the water nozzle to be treated hits the pleat outer peripheral surface of the pleated filter, and the filter cleaning effect is obtained by the pressure. The cylindrical filter 101 is configured such that the shaft 141 of the electric motor 140 is connected to the filter center shaft and is forcedly rotated. By rotating, the cleaning part of the filter is changed sequentially, and the entire outer surface of the cylinder can be cleaned. The number of rotations of the electric motor may be constant, or may be arbitrarily determined artificially. However, it is more preferable to detect the turbidity of filtered water, the pressure inside or outside the filter, and control according to the state of filtration.

  The untreated water to be treated and the suspended matter settled in the case are sequentially discharged from the discharge pipe at the bottom of the case. The point that the filtration proceeds while the turbid component and the remaining treated water are continuously discharged in this way is also a feature of this device, 10 to 20 tons / hour required for ballast water required for ballast water, Furthermore, it is effective to secure a processing amount exceeding 100 ton / hour. In addition, although a valve etc. are not described in the drawing in the drawing, equipment necessary for maintenance and flow rate adjustment can be provided. On the other hand, the filtered water filtered by the filter 101 is guided to the filtered water pipe 107 through the water intake hole 105 provided in the central pipe 104 inside the filter and flows out of the case.

  FIG. 5 is a schematic perspective view illustrating a typical configuration of a pleated filter preferably used in the present invention. This filter has a so-called pleated shape formed by alternately folding a band-like planar base material in a mountain-and-valley shape, and is connected to a cylindrical shape. In FIG. 5, to-be-processed water to be filtered is supplied from the outside of the cylinder of the filter 101, which is a cylindrical pleated filter, and the water filtered by the filter is discharged from the inside of the cylinder.

  A porous resin sheet is used for the filter substrate. For example, a porous structure such as a stretched porous body, a phase-separated porous body, or a nonwoven fabric made of polyester, nylon, polyethylene, polypropylene, polyurethane, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), etc. is used. Is done. In the ballast water treatment, a non-woven fabric made of polyester such as polyethylene terephthalate is particularly preferably used because a high flow rate treatment is performed. As an example of dimensions, as an example used in a treatment apparatus for ballast water that performs 100 ton / hour treatment, the outer diameter of the pleated filter is 700 mm, the axial length is 320 mm, the effective area is 280 mm in height, the pleat depth is 70 mm, There are 420 pleats.

  In the present invention, seawater to be treated is not particularly limited, but generally seawater in harbor areas where ships are anchored contains microorganisms and turbidity, and turbidity is about 1 to 100 degrees. . Examples of microorganisms in seawater that are problematic include larvae such as Escherichia coli, Vibrio cholerae, Enterococcus, Daphnia, starfish, and Asian kelp. These microorganisms are mostly 0.3 to several μm in size. The filter here is intended to remove microorganisms as well as remove turbidity from seawater. The turbidity to be removed contains inorganic components such as silica, and the sizes thereof are various. In order to effectively remove these, a filter capable of filtering plankton of 50 μm or more, preferably 30 μm, more preferably 10 μm or more in seawater is used. A filter capable of removing 99% or more of plankton of 30 μm or more is preferable.

  FIG. 6 shows a basic flow of the ballast water treatment method of the present invention. Generally, seawater taken from the ocean, which is the sea area near the ship's departure port, is filtered by the first filtration step 201 and then sterilized by the first killing step 202, such as residual plankton. . Seawater that has passed through these first water treatment means is stored for a certain period in the storage step 203. The storage is preferably performed for 5 days or more. In general operation, the storage is performed during the voyage period of the ship. Thereafter, the seawater discharged from the storage tank is filtered again by the second filtration step 204. Furthermore, although the 2nd killing process 205 may be passed, this process is not essential. In this way, after the second water treatment means after storage, it is generally discharged into the ocean which is the sea area near the arrival place of the ship. In addition, although the above was demonstrated as a typical operation example, the processing method of this invention should just have the flow of the same processing, for example, the time of loading of ballast water at the time of departure, ie, the stage of ballast water manufacture Thus, it is possible to go through a first filtration step, a storage step, and a second filtration step.

Example 1
Seawater containing 2,800 cells / mL of 355,000 / L ³ plankton having an L size of 50 μm or more and 2,500 cells / mL of S-size plankton having a size of 10 to 50 μm was prepared. First, particles and plankton are removed from seawater by a rotary filter filtration device having the configuration of FIG. 3 using a cylindrical pleated filter capable of removing plankton and particles of 30 μm or more in seawater by 99% or more. An ultraviolet ray of 100 mJ / cm ² was irradiated with an irradiation apparatus. After this seawater was stored in a tank for 5 days, it was filtered again with the same rotary filter filtration device and irradiated with ultraviolet rays. As a result, the plankton of L size was reduced to 0.004 pieces / m ³ and the plankton of S size was reduced to 0.002 cells / mL.

(Example 2)
Seawater containing 344,000 pieces / L ³ of plankton having an L size of 50 μm or more and 3,600 cells / mL of plankton having an S size of 10 to 50 μm was prepared. First, particles and plankton are removed from seawater by a rotary filter filtration device having the configuration of FIG. 3 using a cylindrical pleated filter capable of removing plankton and particles of 30 μm or more in seawater by 99% or more. An ultraviolet ray of 100 mJ / cm ² was irradiated with an irradiation apparatus. When the seawater was stored in a tank for 5 days and then filtered again with the same rotary filter filtration device, the L-size plankton decreased to 0.007 cells / m ³ and the S-size plankton decreased to 0.003 cells / mL.

(Example 3)
Seawater containing 336,000 pieces / m ³ of L size plankton of 50 μm or more and 3,300 cells / mL of S size plankton of 10 to 50 μm was prepared. First, it was treated with a filtration apparatus capable of removing 90% or more of plankton and particles of 50 μm or more, and then a NaClO solution was added and stirred so that the NaClO concentration of seawater was 20 ppm for the killing treatment. When the seawater was stored in the tank for 5 days and then processed again with the same filtration device, the L-size plankton decreased to 0.006 cells / m ³ and the S-size plankton decreased to 0.005 cells / mL.

(Comparative example)
Seawater containing 332,000 pieces / m ³ of L size plankton of 50 μm or more and 3,250 cells / mL of S size plankton of 10 to 50 μm was prepared. First, particles and plankton are removed from seawater by a rotary filter filtration device having the configuration of FIG. 3 using a cylindrical pleated filter capable of removing plankton and particles of 30 μm or more in seawater by 99% or more. An ultraviolet ray of 100 mJ / cm ² was irradiated with an irradiation apparatus. The L-size plankton was reduced to 0.7 pieces / m ³ and the S-size plankton was reduced to 0.12 cells / mL.

DESCRIPTION OF SYMBOLS 1 Ship 2 Ocean 10 Ballast water processing apparatus 11 Tank 12 Filter apparatus 13 Ultraviolet irradiation apparatus 14, 15 Pipe switching part 21, 22 Pump 31, 32, 33, 34, 35, 36, 37, 38 Pipe 101 Filter 102 To-be-processed Water nozzle 103 Case 104 Central pipe 106 Processed water pipe 107 Filtration water pipe 108 Discharge pipe 121 Nozzle port 131 Outer cylinder part 132 Cover part 133 Bottom part 140 Electric motor 141 Shaft 201 First filtration process 202 First kill process 203 Storage process 204 2nd filtration process 205 2nd killing process

Claims (10)

A first water treatment means for treating seawater with a first filtration means for filtering by a filter;
Storage means for storing seawater that has passed through the first water treatment means in a storage tank;
The ship ballast water processing system which has the 2nd water treatment means which processes the seawater which passed through the said storage process with a 2nd filtration means. Each of the first filtering means and the second filtering means is
A filter disposed in a cylinder so as to surround the axis, is provided so as to be rotatable about the axis, and has a pleat shape bent in the radial direction of the cylinder, and to-be-processed that discharges water to be treated to the outer periphery of the filter A case having a water nozzle, an outer cylindrical portion provided inside the nozzle port of the water nozzle to be treated, which surrounds the filter, and filtered water that has passed through the filter from the inside of the cylinder of the filter. A rotary filter filtration apparatus comprising an filtered water flow path leading out and a discharge flow path for discharging discharged water not filtered by the filter to the outside of the case, and an electric motor for rotating the filter The marine ballast water treatment system according to claim 1. The first water treatment means and / or the second water treatment means further includes a killing process by an ultraviolet irradiation lamp having an irradiation amount of 50 mJ / cm ² or more provided in a flow path of filtered seawater. Item 3. A marine ballast water treatment system according to item 1 or 2.   The marine ballast water treatment system according to any one of claims 1 to 3, wherein the filter is a filter capable of removing 99% or more of plankton in seawater by 30% or more.   The marine ballast water treatment system according to any one of claims 1 to 4, wherein the storage step is a step of storing seawater in a tank blocked from sunlight for one day or more. The first filtration means and the second filtration means are the same rotary filter filtration device,
In the first water treatment means, a first pipe configured to send seawater taken from the outside to the treated water nozzle as treated water, and to send the filtered water to the storage tank;
In the second water treatment means, the seawater from the storage tank is sent to the treated water nozzle as treated water, and has a second pipe configured to discharge the filtered water to the outside,
The ship ballast water treatment system according to claim 2, wherein the first pipe and the second pipe are configured to be selectable and switchable. A ballast water treatment device mounted on a ship,
A filter disposed in a cylinder so as to surround the axis, is provided so as to be rotatable about the axis, and has a pleat shape bent in the radial direction of the cylinder, and to-be-processed that discharges water to be treated to the outer periphery of the filter A case having a water nozzle, an outer cylindrical portion provided inside the nozzle port of the water nozzle to be treated, which surrounds the filter, and filtered water that has passed through the filter from the inside of the cylinder of the filter. A rotary filter filtration device comprising an filtered water flow path leading out, and a discharge flow path for discharging drain water that has not been filtered by the filter to the outside of the case, and an electric motor for rotating the filter; ,
An ultraviolet irradiation device having an ultraviolet lamp provided in the flow path of the filtered water;
A storage pipe for guiding the filtered water to a storage tank;
An introduction pipe that can supply either the seawater introduced from the outside or the seawater discharged from the storage tank to be treated water of the rotary filter;
A ballast water treatment apparatus for ships, characterized by comprising:   The said filter is a filter which can remove 99% or more of plankton of 30 micrometers or more in seawater, The processing apparatus for ballast water for ships of Claim 7 characterized by the above-mentioned. A method for treating ballast water that is provided in a ship as ballast water in the first sea area near the departure place and loaded in a tank, and is discharged outside the ship in the second sea area near the arrival place,
When seawater is ballast water in the first sea area, the seawater is filtered using a filter,
When discharging the ballast water in the second sea area, the ship ballast water is again filtered using a filter.   The said filter is a filter which can remove 99% or more of plankton of 30 micrometers or more in seawater, The processing method of the ballast water for ships of Claim 9 characterized by the above-mentioned.

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