JPWO2012124039A1 - Ballast water disinfectant and ballast water treatment device - Google Patents

Abstract

The ballast water treatment apparatus includes a seawater intake line 1, a coarse filtration device 2 that removes coarse substances in seawater taken by the seawater intake line 1, and a pump 3 for feeding the seawater. At the subsequent stage of the pump 3, a sterilizing agent supply device 4, a staying tank 5 in which seawater to which the sterilizing agent supplied from the sterilizing agent supply device 4 is added is retained for a predetermined time, and treated water water supply for supplying the treated water W It has the line 6 and the ballast tank 7 which stores the treated water W sent from the treated water delivery line 6. As this ballast water disinfectant, one containing chlorinated isocyanuric acid is used.

Description

  The present invention relates to a ballast water disinfectant for killing bacteria and plankton contained in ballast water loaded in a ballast tank of a ship. The present invention also relates to a ballast water treatment apparatus for killing bacteria and plankton contained in ballast water loaded in a ballast tank of a ship.

  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 2010-13098 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. Further, these chlorine-based disinfectants have a problem that organic substances contained in seawater react with chlorine and bromine 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.

  On the other hand, since the ballast water treatment system (system) has almost no extra space in the ship, it needs to be compact, and does not require a large amount of electricity. It is required to be easy. Moreover, when using a chemical | medical agent, it is desirable not to pollute the discharge environment of ballast water and to generate the scale resulting from Ca etc. However, there has been no ballast water treatment apparatus that sufficiently satisfies these requirements.

  The present invention solves such problems, kills plankton and bacteria in the seawater supplied to the ballast tank, suppresses the formation of organic halides by residual chlorine, and further stores seawater in the ballast tank. An object of the present invention is to provide a ballast water disinfectant capable of suppressing regrowth of plankton and bacteria during the operation, and a ballast water treatment apparatus using the same.

  In order to solve the above-mentioned problem, first, the present invention supplies a bactericidal agent to water poured into a ship's ballast tank to kill plankton and harmful bacteria, and then sterilizes ballast water stored in the ballast tank. An antibacterial agent for ballast water characterized by containing a chlorinated isocyanuric acid (Invention 1).

According to this invention (Invention 1), since the chlorinated isocyanuric acid has a high effective chlorine concentration, it is possible to obtain a desired effect with a small load compared to sodium hypochlorite or calcium hypochlorite. It is economically superior. In addition, since the rate of decrease in the residual chlorine concentration is small and the amount of organic halides produced by the reaction between 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. Here, the effective chlorine concentration is the Cl ₂ concentration obtained by the DPD colorimetric method.

  In the said invention (invention 1), it is preferable that the said disinfectant is a solid substance having a diameter of 1 mm to 100 mm (invention 2).

  According to this invention (invention 2), by making the particle diameter of the bactericide within the above range, it is possible to achieve both the sustainability of the effect and the stability of the concentration.

  In the said invention (invention 1 and 2), it is preferable that the said chlorinated isocyanuric acid is 1,3,5-trichloroisocyanuric acid (invention 3).

  According to this invention (Invention 3), 1,3,5-trichloroisocyanuric acid has a high effective chlorine concentration of 90% or more, and can obtain a desired effect with a small load, and the residual chlorine concentration. The rate of decline is small.

  Secondly, the present invention provides a sterilizing agent supply device that supplies a sterilizing agent to water poured into a ballast tank of a ship, and a ballast water supply device that supplies the ballast water after supplying the sterilizing agent to the ballast tank. A ballast water treatment apparatus comprising: a ballast water treatment apparatus using chlorinated isocyanuric acid as the disinfectant (Invention 4).

  According to this invention (invention 4), since chlorinated isocyanuric acid has a high effective chlorine concentration, it is possible to obtain a desired effect with a smaller load than sodium hypochlorite or calcium hypochlorite. Therefore, the sterilizer tank in the ballast water treatment apparatus mounted on the ship can be made compact.

  According to the ballast water disinfectant of the present invention, chlorine is used as a disinfectant for ballast water stored in the ballast tank after supplying the disinfectant to the water poured into the ballast tank of the ship to kill plankton and harmful bacteria. Therefore, it is possible to obtain a desired effect with a small load, compared with sodium hypochlorite and calcium hypochlorite, and it is economically superior. In addition, since the rate of decrease in the residual chlorine concentration is small and the amount of organic halides produced by the reaction of organic substances and chlorine contained in seawater is small, there is little concern about the discharge environment. Furthermore, chlorinated isocyanuric acid is suitable as a bactericide for ballast water because it has various storage stability and can be stored safely for a long period of time.

It is the schematic which shows the ballast water treatment apparatus which concerns on one embodiment of this invention. It is a graph which shows the relationship between the residual chlorine density | concentration in seawater after fungicide addition, and elapsed time. It is a graph which shows the relationship between the production amount of total trihalomethane, and elapsed time as a typical item of an organic halide.

In this embodiment, what contains chlorinated isocyanuric acid is used as a bactericide for ballast water. 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 particle size, When too large, since not only the apparent density at the time of storage will become small but dissolution will also take time, it is common to set it as 100 mm or less.

  Next, a ballast water treatment apparatus using the ballast water disinfectant of this embodiment will be described. FIG. 1 is a schematic view showing a ballast water treatment apparatus according to an embodiment of the ultrapure water production method of the present invention.

  As shown in FIG. 1, the ballast water treatment apparatus according to the present embodiment includes a seawater intake line 1 for taking seawater into a ship, and a coarse material for removing coarse substances in seawater taken by the seawater intake line 1. It has the filtration apparatus 2 and the pump 3 as a ballast water supply apparatus for supplying seawater. In the subsequent stage of the pump 3, a sterilizing agent supply device 4 for supplying a sterilizing agent for killing microorganisms and bacteria contained in the filtered seawater and seawater to which the sterilizing agent is added are predetermined. A retention tank 5 that retains for a period of time, a treated water supply line 6 that supplies treated water W derived from the retention tank 5, and a ballast tank 7 that stores treated water W fed from the treated water supply line 6 are provided. . In addition, you may provide separately the filtration apparatus which removes the plankton which exists in the seawater from which the coarse thing was removed by the coarse filtration apparatus 2 between the pump 3 and the disinfectant supply apparatus 4.

  In the ballast water treatment device as described above, the coarse filtration device 2 is taken from a sea chest (seawater inlet) provided on the side of the ship and is contained in seawater taken by the pump 3 through the seawater intake line 1. It is for removing coarse matters of about 10 mm or more among various impurities and aquatic organisms. As such a coarse filtration device 2, a cylindrical strainer (strainer) provided with a hole of about 10 mm, a hydrocyclone that separates coarse matters in a water flow by a difference in specific gravity, a coarse screen is captured and collected by a rotary screen. A device or the like can be used.

  The disinfectant supply device 4 supplies the disinfectant of this embodiment described above to kill microorganisms and bacteria contained in the seawater.

  The retention tank 5 retains chlorine generated from the disinfectant so that the plankton and bacteria are brought into contact with each other for a sufficient time. Such a residence tank 5 may be designed to have a predetermined size and shape in relation to the above residence time, and flow at a predetermined speed. For example, a long flow path may be formed by providing a plurality of partitions in the tank so as to ensure a residence time in the tank. Alternatively, the retention tank 5 may be a simple storage tank that opens the discharge gate or operates the drainage pump when a predetermined time has elapsed after storing the seawater. From the viewpoint of making the equipment compact, the residence time is preferably as short as possible above the lower limit of the contact time described above, and it is desirable to configure the residence tank 5 in consideration of this point.

  Next, a ballast water treatment method that performs killing of bacteria and plankton when ballast water is loaded using the ballast water treatment apparatus shown in FIG. 1 will be described.

  When the ballast water is loaded, the pump 3 is operated to take in the seawater from the seawater intake line 1, first, coarse substances are removed by the coarse filtration device 2, and the sterilant is supplied from the sterilizer supply device 4.

  Here, the disinfectant (chlorinated isocyanuric acid) 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.

  Seawater in which the disinfectant is diffused is introduced into the retention tank 5 and retained (held) for a predetermined time, and plankton and bacteria are killed by the effective chlorine generated from the disinfectant. What is necessary is just to set the residence time to make it retain until it introduce | transduces seawater into the residence tank 5 and supplies a chlorine reducing agent to 0.5 to 10 minutes so that a large plankton may fully die during residence. If the retention tank 5 is less than 0.5 minutes, the sterilizing effect of plankton and bacteria is not sufficient, but if it exceeds 10 minutes, the equipment becomes large, which is not preferable. The residence time in the residence tank 5 as described above is preferably set as short as possible within the above range if the sterilization effect is sufficient.

  Subsequently, seawater (treated water W) that has been retained from the retention tank 5 for a predetermined time and extracted is stored in the ballast tank 7 through the treated water supply line 6. The supply amount of the chlorine reducing agent may be appropriately set according to the desired residual chlorine concentration.

  As described above, in this embodiment, since bacteria and plankton are killed by supplying chlorinated isocyanuric acid as a bactericide, ballast water determined by IMO reliably and inexpensively regardless of the water quality. Ballast water treatment that meets the standards can be realized.

  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. The ballast water treatment apparatus is not particularly limited as long as chlorinated isocyanuric acid is used as a bactericidal agent. For example, the retention tank 5 is not necessarily required. You may make it sterilize with.

  The following specific examples further illustrate the present invention.

[Example 1 and Comparative Example 1]
1,3,5-trichloroisocyanuric acid was added to seawater (TOC: 3 mg / L) collected from Tokyo Bay so as to be 50 mg / L in terms of chlorine, and the chlorine concentration over time was measured. The results are shown in FIG.

  In addition, for comparison, in place of 1,3,5-trichloroisocyanuric acid, sodium hypochlorite was added in a similar manner except that it was 50 mg / L in terms of chlorine. Was measured. The results are shown in FIG.

  As is clear from FIG. 2, in Example 1 using 1,3,5-trichloroisocyanuric acid as a bactericidal agent, the detected concentration of residual chlorine immediately after addition was 40 mg / L, and hypochlorous acid was used as a bactericidal agent. Although the detection concentration of residual chlorine in Comparative Example 1 using sodium was smaller than 51 mg / L, it can be seen that the rate of decrease in residual chlorine concentration is small and the chlorine concentration can be maintained above a certain level for a long time. . In particular, the chlorine concentration of 0.1 mg / L or more was maintained for a long time, and it was confirmed that the killing effect of plankton and the like could be maintained for a long time.

[Example 2 and Comparative Example 2]
Artemia salina eggs were added to 100 mg / L in seawater collected from Tokyo Bay (TOC: 3 mg / L) and allowed to stand at 25 ° C. for 24 hours. As a result, Artemia salina hatched at about 30 pieces / mL.

  1 and 3 mg / L of 1,3,5-trichloroisocyanuric acid as a bactericide is added to the diluted seawater of Artemia Salina diluted with seawater so that the Artemia salina is about 10 pieces / mL As a result, the CT value (disinfectant concentration × contact time) required to kill 99.999% of Artemia salina was 210 mg / L · min.

  For comparison, sodium hypochlorite as a bactericidal agent was added to the product diluted with seawater so that the amount of Artemia salina was about 10 / mL, and required to kill 99.999% of Artemia salina. The CT value was 320 mg / L · min, and 1,3,5-trichloroisocyanuric acid was confirmed to have a higher killing effect.

Example 3
In Example 2 above, 1,3,5-trichloroisocyanuric acid powder (average particle diameter (diameter) 0.3 mm) at a concentration of 1 mg / L (chlorine conversion) for 210 minutes (CT value 210 mg / L · min) ) The amount of trihalomethane produced (concentration) with the passage of time was measured. The results are shown in FIG.

Example 4
In Example 3, the production amount (concentration) of trihalomethane over time was measured in the same manner except that granules of 1,3,5-trichloroisocyanuric acid (average particle diameter (diameter) 3 mm) were used. The results are shown in FIG.

[Comparative Example 3]
For the sake of comparison, the passage of time when left for 210 minutes (CT value 315 mg / L · min) with sodium hypochlorite 1.5 mg / L (chlorine conversion) instead of 1,3,5-trichloroisocyanuric acid The production amount (concentration) of trihalomethane associated with was measured in the same manner. The results are shown in FIG.

  As is clear from FIG. 3, Examples 3 and 4 using 1,3,5-trichloroisocyanuric acid as a bactericidal agent were more effective than triglycerides in Comparative Example 3 using sodium hypochlorite as a bactericidal agent. The amount produced was small. In particular, in Example 4 using granules having an average particle diameter (diameter) of 3 mm, the amount of trihalomethane produced was as small as about 30%.

4 ... Disinfectant supply device 7 ... Ballast tank W ... Treated water

Claims (4)

  A sterilizing agent for ballast water stored in a ballast tank after supplying sterilizing agent to the water poured into the ballast tank of the ship to kill plankton and harmful bacteria, and contains chlorinated isocyanuric acid Ballast water disinfectant.   The said disinfectant is a solid substance having a diameter of 1 mm to 100 mm, and the disinfectant for ballast water according to claim 1.   The said chlorinated isocyanuric acid is 1,3,5-trichloroisocyanuric acid, The disinfectant of ballast water according to claim 1 or 2. A ballast water treatment apparatus comprising: a bactericide supply device that supplies bactericide to water poured into a ballast tank of a ship; and a ballast water supply device that feeds the ballast water after the bactericide is supplied to the ballast tank. There,
A ballast water treatment apparatus using chlorinated isocyanuric acid as the disinfectant.

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