JP2005329300A - Method and apparatus for preparing ballast water for ship - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preparing ballast water for a ship which removes a microbe organism in fresh water or sea water by a method other than a method of making the microbe organism extinct, also simultaneously desalinates the sea water, and prevents the fresh water during transportation from rotting, and a preparation apparatus. <P>SOLUTION: The method and the apparatus for preparing the ballast water for the ship obtain membrane-treated water in which the fresh water is passed through a microfiltration membrane, an ultrafiltration membrane or a reverse osmosis membrane to remove the microbe organism in the fresh water, or membrane-treated water in which the sea water is passed through the reverse osmosis membrane to remove the microbe organism in the sea water and also to be desalinated, and use the membrane-treated water as the ballast water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for manufacturing marine ballast water (hereinafter also simply referred to as “ballast water”) from which microorganisms loaded to stabilize the center of gravity during navigation of the marine vessel are removed.

  Crude oil tankers, ore carriers, car carriers, etc. may sail with low or no cargo. At that time, the hull is lifted by buoyancy, and the screw and rudder are not submerged under the surface of the water, or the hull on the surface of the water is greatly affected by the wind and the maneuverability is impaired, making it extremely dangerous for navigation. For this reason, in order to adjust the buoyancy at the time of navigation, a normal ship carries a ballast water of 30 to 40% by weight of the normal load.

  For example, transportation by crude oil tankers is a round trip between oil-producing countries and consuming countries, and there is no cargo when navigating from consuming countries to oil-producing countries. . On the other hand, a ship loaded with ballast water discharges the ballast water in the sea near the oil-producing country or at a port and reloads with crude oil.

  Ballast water discharged from ships introduces microorganisms that do not inherently inhabit specific areas, resulting in the destruction of marine ecosystems and not only causing serious damage to the lives of the inhabitants, but also worldwide. The destruction of the marine environment has become a serious international problem. For this reason, various methods have been studied on an international scale for the purpose of removing microorganisms in ballast water (Japanese Patent Laid-Open No. 2003-181443, Japanese Translation of PCT International Publication No. 2000-515803, Japanese Patent Laid-Open No. 11-265684, JP 2003-334563 A, JP 2002-504851 A, JP 04-322788 A).

Conventionally, although seawater has been used as ballast water for ships, in recent years, there has been reported an example in which tap water is used as ballast water for ships for the purpose of supporting water supply on remote islands. In addition, fresh water such as drinking water and industrial water is insufficient in oil-producing countries, and tap water is used as marine ballast water, which can be brought into oil-producing countries for effective use.
JP 2003-181443 A (Claims) JP 2000-515803 A (Claims) JP 11-265684 A (Claims) JP 2003-334563 A (Claims) Japanese translation of PCT publication No. 2002-504851 (Claims) JP 04-322788 A (Claims) JP 2003-154360 A (Claims)

  However, if fresh water such as tap water is usually left for several days, even if it is tap water, the added free chlorine disappears, so that it becomes rotten and cannot be taken. For example, since navigating from Japan to oil-producing countries takes about 10 days, fresh water onboard the ship will rot and become unusable. Since the cause of the decay of fresh water is microorganisms in fresh water, the microorganisms may be killed by a known method. However, for example, the method of heating fresh water is not economical depending on the means for procuring heating energy, and it is difficult to completely kill microorganisms. In addition, the method of irradiating fresh water with ultraviolet rays requires a huge amount of power to kill or inactivate all microorganisms, and in order to treat high-flow fresh water, a large number of UV devices must be installed in parallel. Increase the cost of installing the equipment. Also, the method of treating fresh water with chemicals such as iodine and hypochlorous acid requires a high concentration of chemicals depending on the type of bacteria, and a large amount of neutralizing agent is required to neutralize fresh water after treatment. It must be used. As described above, the method of killing microorganisms in fresh water is difficult to completely kill microorganisms, and a small amount of remaining microorganisms grow without being killed, so that these microorganisms are completely removed. The development of the method is anxious.

  Therefore, the object of the present invention is to remove fresh water or a method other than the method of killing microorganisms in seawater, and simultaneously desalinate the seawater to prevent the decay of fresh water during transportation and maintain the utility value of fresh water. It is providing the manufacturing method and manufacturing apparatus of the ballast water for ships.

  In such a situation, the present inventors conducted extensive studies, and as a result, passed the fresh water through a microfiltration membrane, ultrafiltration membrane, or reverse osmosis membrane to obtain membrane-treated water from which microorganisms in the fresh water were removed, and the membrane If treated water is used as ballast water or seawater is passed through a reverse osmosis membrane to remove microorganisms in seawater and obtain a desalted membrane treated water, and the membrane treated water is used as ballast water, Alternatively, microorganisms in fresh water can be effectively removed with a microbial filtration membrane, and in the case of seawater, it is desalinated at the same time, so it is possible to prevent the corruption of fresh water during transportation and maintain the utility value of fresh water. For example, if it is stored in a ballast water storage tank, it has been found that it can be pumped into the ship as ballast water when necessary, and the present invention has been completed.

  That is, the present invention (1) obtains membrane treated water from which microorganisms in fresh water have been removed by passing fresh water through a microfiltration membrane, ultrafiltration membrane or reverse osmosis membrane, and uses the membrane treated water as ballast water. A method for producing marine ballast water is provided.

  Moreover, this invention (2) removes the microbe in seawater by letting seawater pass through a reverse osmosis membrane, and obtains the membrane-treated water desalinated, The marine ballast water which uses this membrane-treated water as ballast water A manufacturing method is provided.

  Moreover, this invention (3) provides the manufacturing method of the said ballast water for ships which the said fresh water is industrial water, tap water, river water, lake water, ground water, or sewage treated water.

  Moreover, this invention (4) provides the manufacturing method of the ballast water for ships which adsorbs and removes the oil component in the said seawater with a hydrophobic adsorbent.

  Moreover, this invention (5) provides the manufacturing method of the ballast water for ships which adds a disinfectant to the said membrane treated water.

  Further, the present invention (6) includes a microfiltration membrane device, an ultrafiltration membrane device or a reverse osmosis membrane device for removing microorganisms in fresh water supplied from fresh water supply means, and a ballast water storage tank for storing membrane treated water. A marine ballast water production apparatus is provided.

  Moreover, this invention (7) is a ballast water manufacturing apparatus for ships provided with the reverse osmosis membrane apparatus which removes the microorganisms in the seawater supplied from the seawater supply means, and desalinates, and the ballast water storage tank which stores membrane treated water Is to provide.

  Moreover, this invention (8) provides the said ballast water manufacturing apparatus for ships further provided with the chemical | medical agent addition means which adds a disinfectant to the said membrane treated water.

  Moreover, this invention (9) provides the said ballast water manufacturing apparatus for ships whose said microfiltration membrane apparatus is an immersion type hollow fiber membrane apparatus or a pressurization type hollow fiber membrane apparatus.

  According to the present invention, microorganisms in seawater or freshwater can be effectively removed with a microbial filtration membrane, and in the case of seawater, it is desalinated at the same time. Can be maintained. Further, if membrane treated water is stored in, for example, a ballast water storage tank, it can be pumped into the ship as ballast water when necessary.

  In the method for producing ballast water for ships of the present invention, the fresh water is not particularly limited, and examples thereof include industrial water, tap water, river water, lake water, ground water, and sewage treated water. Many of these fresh waters contain microorganisms and usually have a turbidity of 1 to 100 degrees.

  The seawater is not particularly limited, and is seawater in a harbor area where a ship is normally anchored. In addition to microorganisms, the oil content is 0.05 to 1.0%, and the turbidity is 1 to 100 degrees. Among microorganisms in freshwater and seawater, microorganisms that particularly affect rot include coliform bacteria, cholera, enterococci, daphnia larvae, North Pacific starfish larvae, Asian kelp larvae, zebra mussel larvae and Toxic algae and the like can be mentioned, and the size of these microorganisms is mostly several μm, and the smallest is 0.3 to 0.5 μm.

  Examples of the microfiltration membrane (MF) used for the treatment of fresh water include a hollow fiber membrane, a flat membrane, a spiral membrane, and a tubular membrane. Among these, the hollow fiber membrane is preferable in that the filtration area per unit volume can be maximized. A hollow fiber membrane uses a large number of hollow fibers arranged in parallel, has a hollow structure, and further communicates with holes forming the hollow structure, and a large number of pores communicating with the holes on the membrane surface. There are external pressure type and internal pressure type. In the present invention, when a microfiltration membrane is used, the pore diameter of the hollow fiber membrane is 0.01 to 0.4 μm, preferably 0.01 to 0.3 μm. In the case of an ultrafiltration membrane used for the treatment of fresh water, the pore diameter of the hollow fiber membrane is 0.002 to 0.01 μm. The size of microorganisms such as bacteria and larvae that inhabit fresh water is usually several μm, and the smallest is about 0.3 to 0.5 μm. Therefore, if a hollow fiber membrane having the above pore diameter is used, These microorganisms such as bacteria and larvae can be almost completely removed. In addition, it is preferable to perform backwashing in order to remove the microorganisms adhering to the membrane surface and restore its filtration ability, but separately from this backwashing, bubbles are bubbled from outside the membrane surface during filtration. It is preferable to use an external pressure type hollow fiber membrane in that an operation of peeling and removing microorganisms attached to the membrane surface can be performed.

  The hollow fiber membrane is used as an immersion type hollow fiber membrane device or a pressure type hollow fiber membrane device. The method using the immersion type hollow fiber membrane device is a method of removing microorganisms in fresh water by sucking the hole side of the hollow fiber of the device immersed in a fresh water storage tank with a suction pump. In addition, as described above, both the immersion type hollow fiber membrane device and the pressure type hollow fiber membrane device generate fine bubbles from below the hollow fiber membrane, and appropriately remove the microorganisms adhering to the hollow fiber membrane. Filtration can be continued while cleaning the surface.

  Examples of the material of the microfiltration membrane used in the present invention include polyethylene, polypropylene, polysulfone, hydrophilized polysulfone, polyvinylidene chloride, polyvinylidene fluoride, chlorinated polyethylene, chlorinated polypropylene, polyacrylonitrile, polyethersulfone, and cellulose acetate. Can be mentioned.

  A reverse osmosis membrane used for the treatment of fresh water or seawater is usually used as a reverse osmosis membrane device incorporating a reverse osmosis membrane module. Examples of the reverse osmosis membrane module include a structure in which a bag-like reverse osmosis membrane is spirally wound around a permeate water collecting pipe and the upper part thereof is covered with an exterior body. Seawater or fresh water is pressed into the reverse osmosis membrane module by a pump. Thereby, salts and organic substances in seawater or fresh water can be removed, and microorganisms such as bacteria and larvae can be almost completely removed. Therefore, when the raw water is seawater, the permeated water of the reverse osmosis membrane is desalinated.

  A method for passing fresh water through a microfiltration membrane, an ultrafiltration membrane or a reverse osmosis membrane, or a method for passing seawater through a reverse osmosis membrane is not particularly limited, but two or more membrane devices incorporating a filtration membrane or a permeable membrane may be used. It is preferable to arrange them in parallel. In this case, even if one membrane apparatus is a backwashing process or a regeneration process, another membrane apparatus can implement a microorganism removal process, and can obtain a large amount of membrane treated water continuously. In addition, the membrane treated water obtained in the microorganism removing step can be stored in a ballast water storage tank, so that the ballast water can be sent from the ballast water storage tank to the anchored ship at a high flow rate. It is preferable in that the berthing period is not extended for pumping blast water.

  In the case of using a microfiltration membrane or an ultrafiltration membrane, a backwashing step of washing the filtration membrane by backwashing is performed. In the microorganism removal process, as time passes, microorganisms or the like that cause clogging of the membrane adhere to the filtration membrane, and the membrane differential pressure rises at the inlet and outlet of the membrane. For this reason, filtration of fresh water is stopped, and the membrane is backwashed with membrane treated water as washing water. By performing the back washing step, the filtration function of the filtration membrane is restored. And when the backwashing process is completed, it moves to a microorganism removal process again, and filtration over a long period of time is enabled by performing this repeatedly.

  In the method for producing ballast water of the present invention, when the raw water is seawater, removing the oil in the seawater before treatment with the reverse osmosis membrane prevents clogging of the surface of the reverse osmosis membrane, and the permeation capacity. It is preferable at the point which can prevent a fall. That is, unlike microorganisms and other turbid substances, the oil cannot be easily removed when it adheres to the membrane surface, clogs the filtration membrane and causes a reduction in filtration capacity.

  The method for removing oil from seawater is not particularly limited, and a known oil / water separator can be used. As the oil / water separator, a device using a hydrophobic adsorbent is preferable because it is a simple method and exhibits a high oil adsorption capability. Examples of the hydrophobic adsorbent include a non-woven filter made of a material such as lipophilic polyethylene or polypropylene, a powder, and a hollow fiber membrane. Specifically, when an oil adsorbent “Diamarus (registered trademark)” is used, the oil can be removed extremely efficiently. For example, seawater having an oil content of 0.05 to 1.0% can be converted to seawater having an oil content of 0.005 to 0.02% by the oil removal process of seawater.

  Moreover, it is preferable to remove in advance turbidity in seawater or fresh water in order to reduce the load of removing microorganisms in the filtration membrane or reverse osmosis membrane. It does not restrict | limit especially as a method of removing the turbidity in sea water or fresh water, A well-known turbidity apparatus can be used. Examples of the turbidity removing device include a sand filtration device, a device equipped with a nonwoven fabric filter cloth made of polyethylene or polypropylene, and a long fiber bundle turbidity device that adsorbs turbidity to a bundle of polyester fibers filled in a filtration tank body. It is done. Use of an oil adsorbent “Diamarus (registered trademark)” is preferred in that both oil removal and turbidity can be removed.

  Moreover, it is preferable to add a bactericidal agent to the membrane-treated water in that the spoilage of fresh water that is the membrane-treated water is further prevented. Hypochlorous acid is mentioned as a disinfectant. The location where the bactericide is added to the membrane treated water is not particularly limited, and includes a pipe connecting the membrane device and the ballast water storage tank, a ballast water storage tank or a pipe connecting the ballast water storage tank and the ballast water tank of the ship, and the like. Can be mentioned.

  The apparatus for producing ballast water according to the present invention includes a microfiltration membrane device, an ultrafiltration membrane device or a reverse osmosis membrane device for removing microorganisms in freshwater supplied from freshwater supply means, and a ballast water storage tank for storing membrane treated water (First device) or a reverse osmosis membrane device that removes microorganisms in seawater supplied from seawater supply means and desalinates, and a ballast water storage tank that stores membrane treated water (second device) Device). Further, both the first device and the second device further include a chemical addition means for adding a bactericidal agent to the membrane treated water. The drug addition means is usually composed of a drug tank, a pump, piping, and the like. Moreover, it is preferable that a 2nd apparatus is equipped with the oil component adsorption removal apparatus which removes the oil component in seawater in the front | former stage of a reverse osmosis membrane apparatus. Further, a turbidity removing device is installed in the first device before the membrane device, and in the second device before the membrane device and after the oil adsorption removing device, if necessary. The fresh water supply means is means for supplying fresh water to the filtration membrane device, and includes a fresh water pump and a fresh water intake pipe having an opening at one end in the fresh water source and the other end connected to the fresh water pump. The seawater supply means is means for supplying seawater to the reverse osmosis membrane device, and includes a seawater pump and a seawater intake pipe having an opening at one end in seawater and the other end connected to the seawater pump. Further, in both the first device and the second device, it is preferable that the piping from the membrane device to the ballast water storage tank and the ballast water storage tank are sterilized. The number of installed ballast tanks, tank type, etc. are not particularly limited. Further, as related equipment of the manufacturing apparatus of the present invention, there are a liquid feed pump for pumping ballast water in a ballast water storage tank, and a liquid feed pipe for connecting the liquid feed pump to a ballast water tank of a ship anchored. The apparatus for producing ballast water of the present invention may be installed on land or on a ship. In the case of installation on a ship, the ballast water tank serves as a storage tank for fresh water or seawater as raw water, and also serves as a ballast water storage tank.

  EXAMPLES Next, the present invention will be described more specifically with reference to examples. However, this is merely illustrative and does not limit the present invention.

  Toda City industrial water (raw water) was treated using the following ballast water production apparatus A under the following operating conditions. Immediately after treatment with raw water and treated water (membrane filtered water), the samples were stored for 1 day, and after storage for 7 days, the odor measurement and the number of bacteria were measured. Moreover, the sand filtration process implemented when manufacturing a normal industrial water or city water about the sample after a 7-day preservation | save was performed, and the odor measurement was performed about the sample after this process. Storage was performed at room temperature and in an air atmosphere. Measurement of general bacteria was performed only on samples immediately after treatment and after storage for 7 days. The results are shown in Table 1.

(Ballast water production equipment A)
The apparatus shown in FIG. 1 was used. The ballast water production apparatus A is mainly composed of a hollow fiber membrane type microbial filtration device 3, and a hollow fiber membrane module 5 “Sterapore SUR31534” (manufactured by Mitsubishi Rayon) comprising a microfiltration membrane having a treatment capacity of 3 m ³ / hour in a treatment tank 4. ) Was used. Further, the hollow fiber membrane type microbial filtration device 3 and the treated water storage tank 6 were connected by a treated water pipe 7, and a suction pump 8 was installed in the treated water pipe 7. Further, a backwash pump 9 was installed so that the filtered water in the treated water storage tank 6 could be backwashed with the backwash pipe 10.

(how to drive)
Raw water was supplied to the ballast water production apparatus A at a treatment amount of 3 m ³ / hour. In the microorganism removal step, air from the blower-11 is bubbled as fine bubbles from the distributor 12 installed in the lower part of the hollow fiber membrane module 5, and filtration is performed while peeling microorganisms and the like adhering to the hollow fiber membrane surface. It was. Moreover, it was set as 1 minute of backwash processes with respect to 15 minutes of microorganism removal processes, and this was repeated. Further, the waste liquid enriched with microorganisms was appropriately drained from the lower part of the treatment tank 4 of the hollow fiber membrane type microorganism filtration device 3.

(Odor measurement)
Based on the method described in JIS K0101, a sensory test is performed by five persons, and the average value is shown. The unit of odor intensity was TON, and the results were displayed as “no odor”, 1 to 3 “very slightly odor”, and 4 or more “odor”.

(Measurement method of general bacteria)
For general bacteria, a sample was added to BGLB (Brilliant Green lactose Bile Broth) and cultured at 35 ° C. for 24 hours, and then the general bacteria were counted. The counted value was shown as CFU per 100 ml.

(Measurement method of total plankton number)
Samples were observed with a microscope and counted. The display was shown as the number per 1 ml.

  It replaced with the ballast water manufacturing apparatus A, and performed by the method similar to Example 1 except having used the ballast water manufacturing apparatus B. In Example 2, the general bacteria and the total plankton number were not measured. The results are shown in Table 1.

(Ballast water production apparatus B and operation method)
An apparatus similar to the ballast water production apparatus A was used except that an ultrafiltration membrane apparatus LOV membrane (manufactured by Asahi Kasei Co., Ltd.) was used instead of the hollow fiber membrane type microorganism filtration apparatus. The operating pressure of the ultrafiltration membrane device LOV membrane is 0.1 MPa. The operation method is the same as that of the ballast water production apparatus A.

  It replaced with the ballast water manufacturing apparatus A, and performed by the method similar to Example 1 except having used the ballast water manufacturing apparatus C. In Example 3, general bacteria and total plankton numbers were not measured. The results are shown in Table 1.

(Ballast water production equipment C)
The apparatus shown in FIG. 2 was used. The ballast water production device C includes a fresh water supply pump 22, a reverse osmosis membrane device 21, and a treated water storage tank 6. The reverse osmosis membrane device 21 includes a reverse osmosis membrane module ES-10 (manufactured by Nitto Denko Corporation). It is loaded. The operation of the reverse osmosis membrane module is performed by a known method, and the operation pressure is 0.6 MPa.

Comparative Example 1
The treatment was performed in the same manner as in Example 1 except that the treatment using the ballast water production apparatus was not performed and the raw water was used as it was as a measurement sample (untreated). The results are shown in Table 1.

Comparative Example 2
It replaced with the process using a ballast water manufacturing apparatus, and it carried out like Example 1 except having boiled raw water at 100 degreeC for 5 minutes. The results are shown in Table 1.

Comparative Example 3
It replaced with the process using a ballast water manufacturing apparatus, and it carried out similarly to Example 1 except having ultrasonically treated raw water as a mechanical crushing with the frequency of 28 kHz and the irradiation time for 10 minutes, and cooled in order to prevent a temperature rise. The results are shown in Table 1.

注）なお、実施例１〜２の１４日保存の臭気の結果は「２」、実施例３の１４日保存の臭気の結果は「１」である。
細菌；ＣＦＵ/１００ｍｌ
総プランクトン数；個/ｍｌ

Note) The results of the odor of 14-day storage in Examples 1 and 2 are “2”, and the result of the odor of 14-day storage in Example 3 is “1”.
Bacteria; CFU / 100ml
Total plankton number / piece / ml

  As raw water, it was carried out in the same manner as in Example 1 except that Arakawa river water was used instead of Toda industrial water. Measurement of general bacteria was omitted. The results are shown in Table 2.

  The same procedure as in Example 2 was performed except that Arakawa river water was used instead of Toda industrial water as raw water. Measurement of general bacteria was omitted. The results are shown in Table 2.

  The same procedure as in Example 3 was performed except that Arakawa river water was used instead of Toda industrial water as raw water. Measurement of general bacteria was omitted. The results are shown in Table 2.

Comparative Example 4
The treatment was performed in the same manner as in Example 4 except that the treatment using the ballast water production apparatus was not performed and the raw water was used as it was as a measurement sample (untreated). The results are shown in Table 2.

Comparative Example 5
It replaced with the process using a ballast water manufacturing apparatus, and performed similarly to Example 4 except having boiled raw water at 100 degreeC for 5 minutes. The results are shown in Table 2.

Comparative Example 6
Instead of the treatment using the ballast water production apparatus, the same procedure as in Example 4 was performed except that raw water was subjected to ultrasonic treatment with a frequency of 28 kHz and an irradiation time of 10 minutes as mechanical crushing and cooled to prevent temperature rise. The results are shown in Table 2.

  Hypochlorous acid was further added to treated water at a concentration of 2.0 mg / l, and the measurement was performed in the same manner as in Example 1 except that the measurement was carried out by storage for 14 days. In Example 7, the general bacteria and the total plankton number were not measured. The results are shown in Table 3.

  Hypochlorous acid was further added to treated water at a rate of 2.0 mg / l, and the measurement was carried out in the same manner as in Example 2 except that the measurement was carried out for 14 days. In Example 8, general bacteria and total plankton numbers were not measured. The results are shown in Table 3.

  Hypochlorous acid was further added to treated water at a rate of 2.0 mg / l, and the same procedure as in Example 3 was performed, except that measurement was carried out by storage for 14 days. In Example 9, general bacteria and total plankton numbers were not measured. The results are shown in Table 3.

Comparative Examples 7-10
Comparative Examples 7 to 9 are those stored for 14 days in Comparative Examples 1 to 3, respectively, and Comparative Example 10 does not perform the treatment using the ballast water production apparatus, and further contains 2.0 mg of hypochlorous acid in the raw water. The measurement was performed in the same manner as in Example 1 except that / l was added and measurement was carried out after 14 days of storage. In Comparative Examples 7 to 9, the general bacteria and the total plankton number were not measured. The results are shown in Table 3.

  It replaced with the ballast water manufacturing apparatus A, and the same method as Example 1 except having used the seawater of Odaiba instead of the point which used the ballast water manufacturing apparatus D, and Toda city industrial water. In Example 10, general bacteria and total plankton numbers were not measured. The results are shown in Table 4.

(Ballast water production device D and operation method)
The raw water is replaced with fresh water, Odaiba seawater, replaced with freshwater supply pump 22, replaced with seawater supply pump, and replaced with reverse osmosis membrane module ES-10, seawater desalination reverse osmosis membrane module SU-810 (manufactured by Toray Industries, Inc.) And the same operation method and the same operation method as the ballast water production apparatus C except that the operation pressure was changed to 0.6 MPa instead of 0.6 MPa.

Comparative Example 11
It replaced with Toda City industrial water and performed similarly to the comparative example 1 except having used the seawater of Odaiba. The results are shown in Table 4.

Comparative Example 12
It replaced with Toda City industrial water and performed similarly to the comparative example 2 except having used the seawater of Odaiba. The results are shown in Table 4.

Comparative Example 13
It replaced with Toda City industrial water and performed similarly to the comparative example 3 except having used the seawater of Odaiba. The results are shown in Table 4.

  As shown in each Example, treated water obtained by treating fresh water with an MF membrane, a UF membrane or an RO membrane did not feel odor, and neither general bacteria nor plankton were detected even when stored for 1 week. Further, the treated water obtained by treating seawater with the RO membrane was fresh water, and even when stored for 1 week, no odor was felt, and general bacteria and plankton were not detected. In this way, since the membrane-treated water does not contain bacteria or plankton, fresh water can be prevented from decaying during the voyage and the utility value of fresh water can be maintained. In addition, the treated water obtained by adding hypochlorous acid to the treated water of these examples did not feel odor even when stored for one week (two weeks in total), and therefore, it can cope with sailing for a longer period. On the other hand, in the boiling treatment of the comparative example, both plankton and general bacteria are killed. However, since the storage container is not sterilized, it is presumed that bacteria are generated using plankton and fungus body as nutrients during storage. The same applies to sonication, but the method of killing mechanical plankton and microorganisms typified by ultrasound is to destroy relatively large items such as plankton, and the contents go out and serve as a nutrient source for bacteria. It can be seen that there are various problems, such as that it tends to occur, and that small things such as microorganisms have insufficient sterilizing effects.

It is a flowchart of the ballast water manufacturing apparatus used in Example 1. It is a flowchart of the ballast water manufacturing apparatus used in Example 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Hollow fiber membrane type microorganism filtration apparatus 4 Treatment tank 5 Hollow fiber membrane module 6 Treated water storage tank 7 Treated water pipe 8 Suction pump 9 Backwash pump 10 Backwash piping 11 Blower 12 Distributor 21 Reverse osmosis membrane device 22 Supply pump A, C Ballast water production equipment

Claims (9)

  Ballast water for ships, characterized in that fresh water is passed through a microfiltration membrane, an ultrafiltration membrane or a reverse osmosis membrane to obtain membrane treated water from which microorganisms in fresh water have been removed, and the membrane treated water is used as ballast water Manufacturing method.   A method for producing marine ballast water, wherein the seawater is passed through a reverse osmosis membrane to remove microorganisms in the seawater and obtain freshly treated membrane treated water, and the membrane treated water is used as ballast water.   2. The method for producing marine ballast water according to claim 1, wherein the fresh water is industrial water, tap water, river water, lake water, ground water or sewage treated water.   3. The method for producing marine ballast water according to claim 2, wherein the oil in the seawater is adsorbed and removed with a hydrophobic adsorbent.   The method for producing marine ballast water according to any one of claims 1 to 4, wherein a bactericidal agent is added to the membrane treated water.   A ship ballast comprising a microfiltration membrane device, an ultrafiltration membrane device or a reverse osmosis membrane device for removing microorganisms in freshwater supplied from freshwater supply means, and a ballast water storage tank for storing membrane treated water Water production equipment.   A marine ballast water production apparatus comprising: a reverse osmosis membrane device that removes microorganisms in seawater supplied from seawater supply means and desalinates, and a ballast water storage tank that stores membrane treated water.   The ship ballast water production apparatus according to claim 6 or 7, further comprising a chemical addition means for adding a bactericide to the membrane treated water. The apparatus for producing ballast water for ships according to claim 6, wherein the microfiltration membrane device is an immersion type hollow fiber membrane device or a pressure type hollow fiber membrane device.

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