JP5776343B2 - Ship ballast water treatment system - Google Patents

Description

  The present invention relates to a ship ballast water treatment system that kills micro-aquatic organisms such as bacteria and plankton contained in ballast water loaded in a ship's ballast tank.

  In general, since ships, especially cargo ships, are designed to include the weight of cargo, etc., ships that are unloaded or lightly loaded must be able to ensure proper submersion depth and safe navigation during unloaded conditions. Because of necessity, seawater is taken at the port before leaving the port to balance the ship. The water used as this ballast is called ballast water. When this ballast water leaves the port without loading, the seawater of the port is loaded into the ballast tank at the port of departure, while the ballast water is drained when loading in the port.

  By the way, when ballast water is poured and discharged by a ship that reciprocates between a loading port and an unloading port, which have different environments, the coastal due to the difference in microorganisms contained in the ballast water at the loading port and the unloading port. There are concerns about adverse effects on ecosystems. Therefore, an international convention for the regulation and management of ship ballast water and sediment was adopted in February 2004 at an international conference on ship ballast water management, which required the treatment of ballast water.

The standard established by the International Maritime Organization (IMO) as a standard for the treatment of ballast water is that the number of organisms (mainly zooplankton) of 50 μm or more contained in the ballast water discharged from the ship is less than 10 in 1 m ³ , 10 μm or more The number of organisms less than 50 μm (mainly phytoplankton) is less than 10 in 1 ml, the number of Vibrio cholerae is less than 1 cfu in 100 ml, the number of E. coli is less than 250 cfu in 100 ml, and the number of enterococci is 100 cfu in 100 ml Is less than

  In order to satisfy such a treatment standard for ballast water, various methods for sterilizing microorganisms in seawater poured into a ballast tank have been proposed. For example, Patent Document 1 discloses an apparatus for sterilizing microorganisms and the like by irradiating ultraviolet rays (UV) after filtering raw water. Patent Document 2 discloses an apparatus for sterilizing microorganisms and the like by injecting ozone into ballast water. Patent Document 3 discloses a ballast water treatment method for sterilizing microorganisms and the like by adding a chlorine-based disinfectant such as sodium hypochlorite or calcium hypochlorite to ballast water and securing a residence time. It is disclosed. Patent Document 4 discloses a method for treating ballast water in which electrolytic chlorine is generated by an electrolytic device to sterilize microorganisms and the like.

JP 2010-207796 A JP 2010-013098 A JP 2009-297610 A Special table 2010-536540 gazette

  However, the ballast water treatment apparatus described in Patent Document 1 not only requires an apparatus for generating ultraviolet rays, but also requires a large amount of electricity, and a generator must be provided in many cases. Furthermore, there is a problem that the UV lamp needs to be cleaned regularly and is troublesome and impractical.

  Further, the ballast water treatment apparatus described in Patent Document 2 requires an apparatus for generating ozone and an amount of electricity, and a generator is often required. Furthermore, there is a problem that an expensive ozone dissolution tank is required and waste ozone treatment is required.

  Therefore, as described in Patent Document 3, a chlorine-based disinfectant such as sodium hypochlorite or calcium hypochlorite is generally used. Sodium hypochlorite is effective chlorine. Since the concentration is only about 13%, it is necessary to load a large amount of medicine on the ship, and sodium hypochlorite is unstable and decomposes at high temperatures. There is a problem that it is necessary to hold and management is troublesome. On the other hand, when calcium hypochlorite dissolves in seawater, calcium sulfate precipitates and becomes a scale, so there is a problem that a device for desalination is required or the scale needs to be removed. Furthermore, these chlorine-based disinfectants have a problem that the organic matter contained in seawater reacts with chlorine to produce organic halides such as trihalomethane, which may deteriorate the discharge environment.

  Further, Patent Document 4 discloses a treatment method for ballast water that generates electrolytic chlorine by an electrolytic device instead of a chlorine-based disinfectant to sterilize microorganisms, but the electrolytic device is expensive and complicated to control. There is a problem that it is difficult to handle.

  Due to these problems of the prior art, as a system for large ships, from the viewpoint of cost, an ultraviolet (UV) sterilizer, an ozone sterilizer, an electrolytic chlorine generator, etc., which itself has a sterilizing function is used. In many cases, a disinfectant is used instead of the conventional system.

  Thus, when a disinfectant is used, when liquid chemicals contain impurities or large organisms, the chemicals are excessively consumed, resulting in increased costs and increased loading capacity. Therefore, in order to reduce the amount of chemicals used as much as possible, impurities and large organisms as solids are separated by solid-liquid separation means such as filtration of the entire amount of ballast water, but a large filtration device is required, There is a problem that it is necessary to secure an installation space.

  Therefore, it is conceivable to use a solid chemical with a high chlorine concentration per unit weight. However, when adding a solid chemical such as calcium hypochlorite to the ballast water as it is, it is dedicated to injecting the solid into the ballast water pipe. There is a problem that equipment is required and installation space needs to be secured.

  An object of the present invention is to solve this problem and provide a ship ballast water treatment system that is compact, does not require a large amount of electricity, and is safe and easy to maintain.

  In order to solve the above-mentioned problems, the present invention provides a ship ballast water treatment system that stores a bactericide in water poured into a ballast tank of a ship to kill plankton and harmful bacteria, and then stores it in the ballast tank. A raw water intake section, a main line for supplying raw water connected to the intake section, water supply means provided in the middle of the main line, and a ballast tank provided at the end of the main line, A bypass line is attached downstream of the water supply means of the main line, and the bypass line joins the main line via a bactericide supply device provided in the middle of the bypass line. A ship ballast water treatment system is provided (Invention 1).

  According to this invention (Invention 1), raw water is supplied from the intake section to the main line, the raw water is separated from the main line to the bypass line, and passes through the disinfectant supply device provided in the middle of the bypass line. Then, by joining the main line and storing the raw water mixed with the disinfectant in the ballast tank, it is possible to kill microaquatic organisms such as bacteria and plankton contained in the raw water (ballast water).

  In the said invention (invention 1), it is preferable to provide the supply means (invention 2) which supplies the amount of water of 1/10 to 1/10000 of the total flow of the said main line to the said bypass line.

  According to this invention (invention 2), a relatively small amount of raw water as 1/10 to 1/10000 of the total flow rate of the main line is supplied to the disinfectant supply device, thereby reducing the size of the disinfectant supply device. be able to.

  In the said invention (invention 1 and 2), it is preferable to provide a filtration means upstream from the disinfectant supply apparatus of the said bypass line (invention 3).

  According to this invention (invention 3), since solid impurities in the raw water are removed by the bypass line, accumulation in the disinfectant supply device can be prevented.

  In the said invention (invention 2 and 3), the concentration sensor of the disinfectant in the raw water supplied to the ballast tank, the concentration sensor of the disinfectant in the water discharged from the disinfectant supply device, and the flow rate of the main line It is preferable that a sensor and a control device for the supply means connected to these sensors are provided, and the control device can control the flow rate of water supplied to the bypass line by the supply means based on the data of these sensors. (Invention 4).

  According to this invention (invention 4), the supply means is based on the concentration of the sterilant of water supplied to the ballast tank, the concentration of the sterilizer of water discharged from the sterilizer supply device, and the flow rate of the main line. By controlling the water flow rate to the bypass line, the concentration of the bactericidal agent of the water supplied to the ballast tank can be properly maintained, and even if the inflow amount to the main line changes, It can retain the killing performance of microaquatic organisms such as bacteria and plankton contained in raw water (ballast water).

  In the said invention (invention 4), it is preferable that the disinfectant supplied from the said disinfectant supply apparatus is chlorinated isocyanuric acid (invention 5). In the above invention (Invention 5), the chlorinated isocyanuric acid is preferably 1,3,5-trichloroisocyanuric acid (Invention 6).

According to the inventions (Inventions 5 and 6), since chlorinated isocyanuric acid has a high effective chlorine concentration, the desired effect can be obtained with a smaller load than sodium hypochlorite or calcium hypochlorite. Can be economical. In addition, since the rate of decrease in residual chlorine concentration is small and the amount of trihalomethane produced by reaction of organic substances and chlorine contained in seawater is small, there is little concern about the discharge environment. Furthermore, chlorinated isocyanuric acid has high storage stability and can be safely stored for a long period of time, and is therefore suitable as a bactericide for ballast water. In particular, 1,3,5-trichloroisocyanuric acid has a high effective chlorine concentration of 90% or more, can achieve a desired effect with a small load, and has a low rate of decrease in residual chlorine concentration. Here, the effective chlorine concentration is the Cl ₂ concentration obtained by the DPD colorimetric method.

  In the said invention (invention 1-6), the said disinfectant supply apparatus is filled with the disinfectant, this disinfectant is a granule or a tablet, and raw water is supplied to the disinfectant supply apparatus from the bypass line. It is preferable to discharge the disinfectant-dissolved water by supplying (Invention 7).

  According to this invention (invention 7), the raw water is supplied from the bypass line to the bactericide supply device, and dissolved in the raw water. Since this bactericide is a granule or a tablet, the concentration of the bactericide solution is controlled. It is easy to do.

  According to the ship ballast water treatment system of the present invention, raw water is supplied from the intake section to the main line, the raw water is separated from the main line to the bypass line, and the disinfectant is provided in the middle of the bypass line. Since the disinfectant solution is discharged from the exit of the disinfectant supply device that passes through the device, the disinfectant concentration can be controlled within a predetermined range. By storing the raw water mixed with the chemical solution in the ballast tank, it is possible to control the concentration of the bactericide in the raw water, thereby effectively killing micro-aquatic organisms such as bacteria and plankton contained in the raw water be able to.

  Compared with sodium hypochlorite and calcium hypochlorite by using chlorinated isocyanuric acid, especially 1,3,5-trichloroisocyanuric acid, especially as the bactericidal agent to be filled in the bactericide supply device Thus, a desired effect can be obtained with a small load, which is economically superior. In addition, since the rate of decrease in residual chlorine concentration is small and the amount of trihalomethane produced by reaction of organic substances and chlorine contained in seawater is small, there is little concern about the discharge environment.

It is a flowchart which shows the processing system of the ship ballast water which concerns on one embodiment of this invention.

  Hereinafter, the ship ballast water treatment system of the present embodiment will be described with reference to FIG. FIG. 1 is a flowchart showing a ship ballast water treatment system according to an embodiment of the present invention.

  In FIG. 1, a ship ballast water treatment system according to the present embodiment includes a water intake unit 1 for raw water W as ballast water, a main line 2 for feeding the raw water W connected to the water intake unit 1, A ballast tank 3 provided at the end of the line 2 is provided, and a first liquid supply pump 4 as a water supply means is provided in the middle of the main line 2. And the bypass line 5 is attached downstream from the 1st liquid feeding pump 4 of the main line 2, The chlorine type disinfectant S processed into the tablet shape was filled in the middle of this bypass line 5. Three sterilizing agent supply devices 6A, 6B, and 6C are installed in series, and after passing through the sterilizing agent supply devices 6A, 6B, and 6C, they merge with the main line 2 again. A second liquid feed pump 7 as a supply unit and an auto strainer 8 as a filtering unit are provided on the upstream side of the bypass line 5 from the disinfectant supply device 6A.

  Further, discharge lines 9A and 9B are provided in parallel with the main line 2, and these discharge lines 9A and 9B communicate with a part of the main line 2 in common, and the end of the discharge line 9B is a drainage section. It is 10. In addition, 11A and 11B are water supply valves, and 12A and 12B are drain valves.

  Further, a first chlorine concentration sensor 13 and a second chlorine concentration sensor 14 as chemical liquid sensors are provided immediately before the ballast tank 3 of the main line 2 and downstream of the disinfectant supply device 6C of the bypass line 5. It has been. On the other hand, a reducing agent supply pipe 16 communicating with the reducing agent supply mechanism 15 is connected to the discharge line 9A, and a third chlorine concentration sensor 17 is also provided in the discharge line 9B. The flow rate of the main line 2 can be measured by a flow meter (not shown). The first chlorine concentration sensor 13, the second chlorine concentration sensor 14, the third chlorine concentration sensor 17, the second liquid feed pump 7, the reducing agent supply mechanism 15, and the flow meter are a computer or the like (not shown). The control device is connected to the control device, and the control device can control the second liquid feeding pump 7 and the reducing agent supply mechanism 15 based on the data of the sensors 13, 14, 17 and the data of the flowmeter. ing.

In the ship ballast water treatment system as described above, as the ballast water disinfectant S, one containing chlorinated isocyanuric acid can be used. Here, isocyanuric acid is an isotope of cyanuric acid represented by the molecular formula of C ₃ H ₃ N ₃ O ₃ , and the IUPAC name is 1,3,5-triazinan-2,4,6-trione. . Chlorinated isocyanuric acid has a structure in which hydrogen bonded to nitrogen of this isocyanuric acid is substituted with chlorine, and is solid at room temperature. Chlorinated isocyanuric acid has a low degree of decrease in residual chlorine concentration when dissolved in seawater, can maintain a bactericidal effect for a long time, is highly safe against other organisms, and has excellent storage stability. ing.

  Examples of such chlorinated isocyanuric acid include dichloroisocyanuric acid (1,3-dichloroisocyanuric acid) or trichloroisocyanuric acid (1,3,5-trichloroisocyanuric acid). Among these, dichloroisocyanuric acid has an effective chlorine concentration of about 65%, and trichloroisocyanuric acid has an effective chlorine concentration of about 90%. Therefore, trichloroisocyanuric acid has a high effective chlorine concentration and is advantageous in price and volume. Acids are preferred, and these can be used alone or in combination.

  The chlorinated isocyanuric acid is preferably a solid or granular material such as a microtablet, and preferably has a size (diameter) of 1 mm or more. When the size of the chlorinated isocyanuric acid is less than 1 mm, the dissolution rate is too fast and the rate of decrease in the effective chlorine concentration is increased. In addition, although there is no restriction | limiting in particular about the upper limit of a diameter, since not only the apparent density at the time of storage will become small but it will also take time for melt | dissolution, it is common to set it as 100 mm or less.

  The disinfectant S as described above may be added in an amount of 1 to 100 mg / L (chlorine conversion), preferably 5 to 70 mg / L, with respect to the ballast water (seawater). If the amount of chlorinated isocyanuric acid added is less than 1 mg / L in terms of chlorine, a sufficient bactericidal effect cannot be obtained. On the other hand, if it exceeds 100 mg / L, no further improvement in bactericidal effect can be obtained and it is not economical. In addition, the tendency to generate a large amount of by-products such as trihalomethane is increased, and there is an increased concern that it adversely affects the environment. In addition, what is necessary is just to adjust the addition amount of chlorinated isocyanuric acid suitably with the quantity of the organic substance (DOC, POC, etc.) in ballast water, and the density | concentration of ammonia.

  Further, as will be described later, the reducing agent supply mechanism 15 supplies a reducing agent to the waste ballast water B in which chlorine remains to reduce the remaining chlorine, thereby reducing the residual chlorine concentration to the target residual chlorine concentration. . Drain to the external environment after reducing to the target residual chlorine concentration.

  As the reducing agent supplied from the reducing agent supply mechanism 15, sodium sulfite, sodium bisulfite (sodium hydrogen sulfite), sodium thiosulfate, or the like can be used. It is particularly preferable to use sodium thiosulfate.

  Next, a ballast water treatment method for killing bacteria and plankton when loading ballast water using the ship ballast water treatment apparatus shown in FIG. 1 will be described below.

  First, when the raw water (ballast water) W is loaded, if the intake valve 1 is opened with the water supply valves 11A and 11B opened and the drain valves 12A and 12B closed, the water head between the water surface and the ballast tank 3 in the initial state. Due to the difference, the raw water W flows from the intake portion 1 through the main line 2 and flows into the ballast tank 3 only by not driving the first liquid feed pump 4 or by driving it with slight power.

  At this time, by driving the second liquid feed pump 7, the raw water W is branched and supplied from the main line 2 to the bypass line 5, and the sterilizing agent supply devices 6A, 6B, 6C filled with the sterilizing agent S are supplied. By passing, the bactericide solution W1 in which the bactericide S is dissolved can be obtained. The concentration of the bactericide solution W1 is substantially constant at the same flow rate, and the concentration can be controlled by changing the flow rate (≈flow rate). In particular, in this embodiment, since the disinfectant S processed into a tablet shape is used, the disinfectant supply devices 6A, 6B, 6C can be easily filled, and the disinfectant S dissolution rate can be kept almost constant. It is possible.

  For example, in the ballast water of a ship, the concentration of the sterilizing agent S in the raw water W flowing into the ballast tank 3 needs to be within a predetermined range in order to maintain sterilization. However, as the raw water W is filled in the ballast tank 3, the head difference from the water surface is reduced, so that the driving force of the first liquid feed pump 4 is increased, and the raw water passing through the main line 2 accordingly. The flow rate of W varies. Moreover, the consumption of chlorine in the bactericide S may increase due to impurities. However, in the ballast water of the ship, the concentration of the sterilizing agent S in the raw water W flowing into the ballast tank 3 needs to be within a predetermined range in order to maintain the sterilizing ability. Therefore, the second liquid feed pump 7 is controlled based on the data of the first chlorine concentration sensor 13, the second chlorine concentration sensor 14, and the flow meter of the main line 2.

  Specifically, the branch flow rate to the bypass line 5 by the second liquid feeding pump 7 is in the range of 1/10 to 1/10000, particularly 1/10 to 1/1000 of the total flow rate of the main line 2. It is preferable to control by. If the branch flow rate to the bypass line 5 is more than 1/10 of the total flow rate of the main line 2, it becomes difficult to control the concentration of the bactericide solution W1, and as a result, the amount of the bactericide S dissolved increases, Not only is a large amount of load required, but a high-capacity second liquid delivery pump 7 is required, which is not economical, while the branch flow rate to the bypass line 5 is less than 1/10000 of the total flow rate of the main line 2. It becomes difficult to control the concentration of the sterilizing agent solution W1, the concentration of the sterilizing agent S in the raw water W supplied to the ballast tank 3 is less than 5 mg / L, and a sufficient sterilizing effect cannot be obtained, or the concentration of the sterilizing agent solution W1. Becomes higher and trihalomethane tends to increase, which is not preferable.

  Moreover, in this embodiment, since the autostrainer 8 as a filtration means is provided in the upstream of the disinfectant supply device 6A of the bypass line 5, turbid substances in the raw water W, relatively large aquatic organisms, etc. Solid impurities such as foreign matters can be removed here, and solid impurities can be prevented from being mixed and deposited in the sterilizing agent supply devices 6A, 6B, 6C. In addition, the discharged water of the auto strainer 8 is discharged via the discharge path 8A.

  Thus, by making the raw water W supplied to the ballast tank 3 have a predetermined concentration of the chlorine agent S, plankton and bacteria in the raw water W as the ballast water are killed by the effective chlorine generated from the bactericide S. Can do. In particular, by controlling the second liquid feed pump 7 based on the data of the first chlorine concentration sensor 13, the second chlorine concentration sensor 14, and the flow meter of the main line 2, the raw water W is obtained. Regardless of the water quality, ballast water can be reliably and inexpensively treated to meet the ballast water standards set by IMO.

  Next, the discharge of ballast water will be described. When discharging the ballast water from the ballast tank 3, the drainage valves 12A and 12B are opened, and the first liquid feed pump 4 is driven in a state where the drainage section 10 is opened with the water supply valves 11A and 11B closed. . As a result, the discharged ballast water B in the ballast tank 3 is discharged from the drainage section 10 via the discharge line 9B via the discharge line 9A through a part of the main line 2.

  At this time, the residual chlorine concentration in the discharged ballast water B is sensed by the third chlorine concentration sensor 17, and the discharge line 9A is discharged from the reducing agent supply mechanism 15 by the control mechanism according to the residual chlorine concentration in the discharged ballast water B. By adjusting the amount of the reducing agent supplied to the base, residual chlorine can be reduced and the production of trihalomethane can be suppressed.

  The present invention has been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiments, and various modifications can be made. For example, as the sterilizing agent supply device, three units 6A, 6B, and 6C are provided in series in consideration of downsizing of each device, effective use of the sterilizing agent S, and stability of concentration. One or two supply devices may be provided. Moreover, although the autostrainer 8 was used as the filtering means, other filtering means such as a membrane filtering device such as a filter may be used. Further, the reducing agent may be added to the ballast tank 3 in advance.

The following specific examples further illustrate the present invention.
[Example 1]

  Artificial seawater with a salt concentration of 4% by weight was prepared, and rotifer as zooplankton and tetracelmis as phytoplankton were added to the artificial seawater at concentrations of 275 N / mL and 10000 N / mL, respectively. It was.

  In the processing system shown in FIG. 1, a test simulation system in which a filter having a pore diameter of 50 μm is provided instead of the auto strainer 8 and only one sterilizing agent supply device is prepared, and the sterilizing agent supply device has an about 5 mm particle diameter. A tablet of 62.1 g of 1,3,5-trichloroisocyanuric acid was charged.

  In the simulation processing system as described above, the water supply valves 11A and 11B are opened, the drainage valves 12A and 12B are closed, the first liquid feed pump 4 is driven, and the main intake flow rate from the water intake section 1 is 10 L / min. While supplying the simulated raw water W to the line 2, the second liquid feed pump 7 is driven, and the simulated raw water W is drawn into the bypass line 5 at a flow rate of 300 mL / min (3% of the main line 2) to supply the sterilizing agent. The water was passed through the apparatus and then joined to the main line 2 as it was.

  When the chlorine concentration of the raw water W at the outlet of the disinfectant supply device was measured, it was almost constant at 1000 mg / L. Further, the chlorine concentration and the biological concentration at the outlet of the main line 2 (corresponding to the inlet of the ballast tank 3) were measured. Further, the simulated raw water W collected at the outlet of the main line 2 was left as it was, and the chlorine concentration and biological concentration of the simulated raw water W after being left for 30 minutes, 60 minutes and 120 minutes were measured. The results are shown in Table 1. For comparison, Table 1 shows the results of measuring the chlorine concentration and the biological concentration of the simulated raw water W after leaving the simulated raw water W for 120 minutes when not passing through the disinfectant supply device (reference example). Show. The chlorine concentration was measured by the DPD colorimetric method, and the biological concentration was calculated by counting living things by dyeing and visual coefficient measurement with a microscope.

As is clear from Table 1, in the ship ballast water treatment system of Example 1, rotifers and tetraselmis were already killed at the exit of the main line 2, and it was confirmed that the effect was maintained for 120 minutes. It was done. By applying the result to the largest oil tankers ballast tank capacity 100,000 m ^3, when the processing the ballast water injection flow rate 10,000m ³ / h, 1,3,5- trichloro isocyanuric acid is required 3t. When sodium hypochlorite, which is the same chlorinated disinfectant, is used, a 13% aqueous solution is generally used, so the loading capacity is 23 tons, a large chemical tank is required, and sodium hypochlorite A chiller tank at 20 ° C. for suppressing self-decomposition is also required. From these, it can be said that it is preferable to use 1,3,5-trichloroisocyanuric acid used in this example as the bactericidal agent S.
[Example 2]

  Using the same treatment system as in Example 1, the flow rate of the simulated raw water W in the main line 2 was changed to 5 L / min, and water was passed through the bypass line 5 at 120 mL / min (2.4% of the main line 2). However, when the chlorine concentration of the raw water W at the outlet of the disinfectant supply device was measured, it was almost constant at 1300 mg / L. At this time, the chlorine concentration at the outlet of the main line 2 and the biological concentration were measured. Further, the simulated raw water W collected at the outlet of the main line 2 was left as it was, and the chlorine concentration and biological concentration of the simulated raw water W after being left for 30 minutes, 60 minutes and 120 minutes were measured. The results are shown in Table 2.

  The ship ballast water treatment system of the present invention can be suitably used for the production of ballast water used in various ships, particularly large ships.

DESCRIPTION OF SYMBOLS 1 ... Water intake part 2 ... Main line 3 ... Ballast tank 4 ... 1st liquid feeding pump (water feeding means)
5 ... Bypass lines 6A, 6B, 6C ... Disinfectant supply device 7 ... Second liquid feed pump (supply means)
8 ... Auto strainer (filtering means)
13: First chlorine concentration sensor (chemical solution sensor)
14 ... Second chlorine concentration sensor (chemical sensor)
W ... Raw water S ... Disinfectant

Claims (5)

A ship ballast water treatment system for storing water in a ballast tank after supplying fungicides to the water poured into the ballast tank of the ship to kill plankton and harmful bacteria,
A raw water intake section, a main line for supplying raw water connected to the intake section, water supply means provided in the middle of the main line, and a ballast tank provided at the end of the main line,
A bypass line is attached downstream from the water supply means of the main line,
The bypass line joins the main line via a disinfectant supply device provided in the middle of the bypass line ,
The disinfectant supply device is filled with a disinfectant composed of chlorinated isocyanuric acid, and the disinfectant is in the form of granules or tablets, and is sterilized by supplying raw water from the bypass line to the disinfectant supply device. Ship ballast water treatment system characterized by discharging agent-dissolved water .   The ship ballast water treatment system according to claim 1, further comprising supply means for supplying a water amount of 1/10 to 1/10000 of a total flow rate of the main line to the bypass line.   The ship ballast water treatment system according to claim 1 or 2, further comprising a filtering means upstream of the disinfectant supply device of the bypass line.   Disinfectant concentration sensor in raw water supplied to the ballast tank, disinfectant concentration sensor in water discharged from the disinfectant supply device, main line flow rate sensor, and the supply connected to these sensors The ship according to claim 2 or 3, characterized in that said control apparatus is capable of controlling a flow rate of water supplied to the bypass line by said supply means based on data of these sensors. Ballast water treatment system. 2. The ship ballast water treatment system according to claim 1 , wherein the chlorinated isocyanuric acid is 1,3,5-trichloroisocyanuric acid.

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