JP2006000728A - Method for preparing ballast water and apparatus for preparing ballast water to be loaded onto vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently preparing such ballast water that a microbe which does not live originally in a specified sea area is not brought in the specified sea area and the marine environment is not damaged even when a large quantity of such ballast water is discharged from a ship, and to provide an apparatus for preparing ballast water to be loaded onto a vessel. <P>SOLUTION: This method for preparing ballast water comprises a microbe removing step of removing the microbe in the seawater loaded onto the vessel by making the seawater pass through a microbe filtering membrane on board and a backwashing step of backwashing the microbe filtering membrane. A filtrate obtained at the microbe removing step is used as ballast water. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing ballast water (hereinafter also simply referred to as “ballast water”) and a ship-mounted ballast water manufacturing apparatus that do not adversely affect the marine environment to be loaded for the purpose of stabilizing the center of gravity during navigation of the ship.

  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 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.

  In recent years, ballast water discharged from ships has brought in microorganisms that do not inherently live in specific waters, which has resulted in the destruction of marine ecosystems, not only causing serious damage to the lives of those waters. The destruction of the global marine environment has occurred and 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 the ballast water.

As a method for removing microorganisms in seawater pumped as ballast water, for example, a method of killing microorganisms by heating seawater (Japanese Patent Laid-Open No. 2003-181443), inactivating the microorganisms by irradiating the seawater with ultraviolet rays (Japanese Unexamined Patent Publication No. 2000-515803, Japanese Unexamined Patent Publication No. 11-265684), a method of killing seawater through an electrolyzer (Japanese Unexamined Patent Publication No. 2003-334563), a method of treating with iodine (Special Table 2002) No. 504851) and a method of treating with hypochlorous acid (Japanese Patent Laid-Open No. 04-322788) have been proposed.
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, the method of heating seawater is not economical depending on the heating energy procurement means, and it is difficult to completely kill microorganisms. In addition, the method of irradiating seawater with ultraviolet rays requires a huge amount of power to kill or inactivate all the microorganisms, and in order to process high-flow seawater, many UV devices must be installed in parallel. Increase the cost of installing the equipment. Further, in the method of killing microorganisms by the bactericidal effect of chlorine ions generated by electrolysis by passing seawater through an electrolyzer, some microorganisms are not killed by chlorine ions, and all microorganisms cannot be killed. In addition, the method of treating seawater with chemicals such as iodine and hypochlorous acid requires a high concentration of chemicals to be killed depending on the type of microorganisms. It must be used.

  As described above, the method of killing microorganisms in seawater is difficult to completely kill microorganisms, and there is a concern about the influence of contamination by carcasses on the ecosystem. Furthermore, since a small amount of microorganisms remaining without being killed grow during transportation, development of a method for completely removing these microorganisms is eagerly desired. Moreover, although the method of removing the microbe in seawater by letting seawater pass through a filtration membrane (Unexamined-Japanese-Patent No. 2003-154360), the membrane filtration water obtained by this method is used for the washing | cleaning of seafood, etc. It is not intended for use in ship ballast water. Moreover, in order to process a large amount of seawater with a filtration membrane, it is usually not efficient because the filtration area is increased or a long period of time is required. Conventionally, a large amount of seawater cannot be treated with a filtration membrane. Was that.

  Accordingly, an object of the present invention is to provide an efficient method for producing ballast water that does not bring in microorganisms that do not naturally inhabit a specific sea area due to a large amount of ballast water discharged from a ship, and that does not destroy the marine environment, and The object is to provide a ship-mounted ballast water production apparatus.

  In such a situation, the present inventors have conducted intensive studies, and as a result, removed the microorganisms in the seawater by passing the seawater loaded on the ship through the microorganism filtration membrane on the ship, and microbial filtration by backwashing. If the membrane filtered water obtained in the microorganism removing step is used as ballast water, it can be treated with a filtered membrane during navigation, and the pumped seawater The seawater in the harbor area where the ship is anchored and contains a relatively large amount of oil that contaminates the filter membrane, but if the oil is removed in advance before it is processed with the filter membrane, the processing efficiency of the filter membrane is improved. As a result, the present invention has been completed.

  That is, the present invention (1) includes a microbial removal step of removing microorganisms in seawater by passing seawater loaded on the vessel through the microbial filtration membrane on the vessel, and a backwashing step of washing the microbial filtration membrane by backwashing. And a method for producing ballast water using membrane filtered water obtained in the microorganism removing step as ballast water.

  In the present invention (2), the seawater is respectively loaded in a plurality of ballast tanks in a ship, and the microorganism removal step is obtained by passing the seawater of one ballast tank through a microorganism filtration membrane. A circulation process for returning membrane permeated water to the one ballast water tank, which is also performed for seawater in other ballast water tanks in order.

  In the present invention (3), the seawater is one of a plurality of ballast tanks in a ship, one of which is an empty tank, and is loaded in another ballast tank. Perform one-pass processing to pass the seawater in the aquarium through the microbial filtration membrane and supply the obtained membrane permeated water to the empty water tank, then pass the seawater in the other ballast water tank through the microbial filtration membrane, and empty the obtained membrane permeated water The present invention provides a method for producing the ballast water, in which the one-pass treatment to be supplied to the one ballast water tank that has become a water tank is performed, and the one-pass treatment is sequentially performed.

  Moreover, this invention (4) provides the manufacturing method of the said ballast water which removes the oil component in seawater at least before processing with the said microorganisms filtration membrane.

  Moreover, this invention (5) provides the manufacturing method of the said ballast water whose said microorganisms filtration membrane is a hollow fiber membrane.

  Moreover, this invention (6) provides the manufacturing method of the said ballast water which adsorbs and removes the oil component in the said seawater with a hydrophobic adsorbent.

  In addition, the present invention (7) is obtained by a plurality of ballast water tanks loaded with pumped seawater, a microbial filtration membrane apparatus for removing microorganisms in seawater stored in the ballast water tank, and the microbial filtration membrane apparatus. A tank for backwashing that stores membrane filtrate, a seawater supply pipe for connecting each ballast water tank and the microorganism filtration membrane device, and a membrane filtrate water supply pipe for connecting the backwash tank and each ballast water tank. Provided is a ship-mounted ballast water production apparatus characterized by comprising.

  Moreover, this invention (8) provides the said ship mounted ballast water manufacturing apparatus which installs the oil content adsorption removal apparatus which removes the oil content in seawater at the front | former stage of the said microorganisms filtration membrane apparatus and the back | latter stage of a ballast water tank. It is.

  Moreover, this invention (9) provides the said ship mounted ballast water manufacturing apparatus whose said microbe filtration membrane apparatus is an immersion type hollow fiber membrane apparatus or a pressurization type hollow fiber membrane apparatus.

  According to the present invention, since a large amount of seawater used as ballast water can be effectively treated with a microbial filtration membrane during navigation of the ship, microorganisms that do not originally inhabit the specific sea area are brought in by the ballast water discharged from the ship. And will not destroy the marine environment. In addition, even seawater containing a relatively large amount of oil is removed in advance before being treated with the microbial filtration membrane, so that the microbial filtration membrane is not contaminated and can be treated stably for a long period of time. it can.

  In the method for producing ballast water according to the present invention, the seawater loaded on the ship is not particularly limited, but is usually seawater in a port area where the ship is anchored. It is contained by 0.5 to 1.0%, and the turbidity is 1 to 100 degrees. In addition, among the microorganisms in seawater, microorganisms of particular international concern include coliforms, cholera, enterococci, daphnia larvae, North Pacific starfish larvae, Asian kelp larvae, zebra larvae 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.

  The ballast water of the present invention is manufactured on a ship. As a result, a large amount of seawater can be effectively treated with the microorganism filtration membrane during the navigation of the ship, and microorganisms that do not originally live in the specific sea area are not brought in by the ballast water discharged from the ship. The microorganism removing step in the present invention is a step of removing microorganisms in seawater by passing seawater loaded on a ship through a microorganism filtration membrane.

  Next, an example of the manufacturing method of the ballast water of this invention is demonstrated with reference to FIG.1 and FIG.2. FIG. 1 shows a double hull structure of a tanker, (A) is a schematic cross-sectional view cut along a direction orthogonal to the bow stern direction of the hull, and (B) is a schematic cross-sectional view cut along the bow stern direction of the hull. is there. FIG. 2 is a flow diagram of an apparatus for carrying out the method for producing ballast water of this example. Seawater is loaded on a ballast water tank 2 divided into a plurality of chambers in a double hull structure as shown in FIG. 1, for example. That is, in FIG. 1, in the ship 1, the inner tank is the crude oil tank 3, and the outer tank is the ballast water tank 2. In this example, the ballast tank 2 has six ballast tanks 11 to 16 which are divided into two in the width direction of the ship and into three in the length direction of the ship.

  In FIG. 2, the ship-mounted ballast water manufacturing apparatus 10 is mounted on the ship as a whole, and includes a plurality of ballast water tanks 2 (11 to 16) for loading the pumped seawater, and the ballast water tank 2. Microbial filtration membrane device 4 for removing microorganisms in seawater stored in the tank, a backwash tank 6 into which membrane filtrate obtained by the microbial filtration membrane device 4 flows, ballast water tanks 11 to 16 and a microbial filtration membrane. The seawater supply pipes 21 to 26 for connecting the seawater inflow pipe 28 of the device 4, the membrane filtered water outflow pipe 38 of the backwash tank 6, and the membrane filtrate water supply pipes 31 to 36 for connecting the respective ballast water tanks 11 to 16 are provided. The oil adsorption removal apparatus 5 which removes the oil component in seawater is provided in the front | former stage of the microorganisms filtration membrane apparatus 4 as needed. In addition, a turbidity device (not shown) can be installed in the subsequent stage of the oil content adsorption removing apparatus 5 and in the upstream stage of the microorganism filtration membrane apparatus 4 as necessary. Moreover, as a related facility of the manufacturing apparatus of this invention, there exists a liquid feed pump etc. which supply the seawater stored in the ballast water tank 2 to the microorganisms filtration membrane apparatus 4.

  Examples of the method for removing the microorganisms in the seawater using the ship-mounted ballast water manufacturing apparatus 10 include a circulation processing method in which a microorganism removal step is performed for each ballast water tank, or a one-pass processing method using an empty ballast water tank. . These can be implemented by appropriately operating the valve in FIG.

  An example of the circulation processing method is shown below. First, the seawater in the ballast tank 11 is treated alone. That is, the seawater of the ballast water tank 11 is passed through the microorganism filtration membrane, and the obtained membrane permeated water is returned to the ballast water tank 11 for circulation treatment. Next, the seawater in the ballast tank 12 is treated alone. That is, the seawater in the ballast water tank 12 is passed through the microorganism filtration membrane, and the obtained membrane permeated water is returned to the ballast water tank 12 for circulation treatment. This is sequentially performed for the other ballast water tanks 13-16. In addition, in the ballast water tanks 11 to 16, it is preferable that the seawater intake port of the seawater supply pipe and the membrane filtrate water outlet of the membrane filtrate supply pipe be separated as much as possible.

  An example of the one-pass processing method is as follows. Seawater is loaded into another ballast water tank, one of which is an empty ballast tank among the plurality of ballast tanks 2 in the ship. In this case, the empty ballast water tank serves as a membrane filtrate water storage tank. For example, seawater is loaded on the ballast tanks 11 to 15 and the ballast tank 16 is an empty ballast tank. A one-pass process is performed in which the seawater in the ballast water tank 11 is passed through the microbial filtration membrane and the obtained membrane permeated water is supplied to the empty ballast water tank 16, and then the seawater in the ballast water tank 12 is passed through the microbial filtration membrane. Is supplied to the empty ballast water tank 11, and the one-pass processing is sequentially performed. Thereby, after completion | finish of a microorganism removal process, membrane filtration water will be stored in ballast water tanks other than one empty ballast water tank among several ballast water tanks. In addition, it is preferable that the arrangement | positioning of the ballast water tank in which membrane filtered water was stored has the positional relationship which keeps the gravity center of a ship body stable. Further, after the microorganism removal step, the remaining portion of the seawater remaining at the bottom of the ballast water tank may be subjected to a known sterilization treatment such as addition of a chemical such as hypochlorous acid or a heat treatment. In this case, since the remaining amount of the seawater is relatively small, the amount of the disinfectant used may be small, and the energy consumed by heating is small.

  Examples of the shape of the microorganism filtration membrane include a hollow fiber membrane, a flat membrane, and a tubular membrane. Among these, the hollow fiber membrane is preferable in that the filtration area per unit volume can be maximized.

  The hollow fiber membrane has a hollow structure, and further has a plurality of pores communicating with the holes forming the hollow structure and communicating with the holes on the membrane surface, and there are an external pressure type and an internal pressure type. . In the present invention, when a microfiltration membrane is used as the microorganism filtration membrane, the pore diameter of the hollow fiber membrane is 0.01 to 0.4 μm, preferably 0.01 to 0.3 μm. Moreover, when using an ultrafiltration membrane, it is 0.002-0.01 micrometer as a diameter of the pore of a hollow fiber membrane. The size of microorganisms such as bacteria and larvae inhabiting seawater 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, backwashing is performed to remove microorganisms adhering to the membrane surface and restore its filtration ability, but separately from this backwashing, bubbles are bubbled from the outside of the membrane surface during filtration to the membrane surface. It is preferable to use an external pressure type hollow fiber membrane in that an operation of peeling and removing attached microorganisms 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 submerged hollow fiber membrane device is a method of removing microorganisms in the seawater by passing the inside of the hollow fiber of the device immersed in the seawater storage tank by a head difference or suction by a suction pump or the like. . 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. It can be filtered while washing the surface.

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

  The method for passing seawater through the microbial filtration membrane is not particularly limited, but two or more microbial filtration membrane devices incorporating the microbial filtration membrane may be arranged in parallel. In this case, even if one microbial filtration membrane device is in the backwashing step, the other microbial filtration membrane device can perform the microbial removal step, and a large amount of membrane filtered water can be obtained continuously.

  The backwashing step of the ballast water production method is a step of washing the microbial filtration membrane by backwashing. In the microorganism removal process, as time elapses, microorganisms or the like that cause clogging of the membrane adhere to the microorganism filtration membrane, and the membrane differential pressure rises at the inlet and outlet of the membrane. For this reason, the filtration of seawater is stopped, and the microbial filtration membrane is back-washed using the membrane filtrate as washing water. By performing the backwashing step, the filtration function of the microorganism 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. Note that the microbial concentrate produced by backwashing is subjected to known sterilization treatments such as addition of chemicals such as hypochlorous acid and heat treatment. Since this microbial concentrate is relatively small, the amount of the bactericide used may be small, and the energy consumed by heating is small.

  In the method for producing ballast water of the present invention, removing oil in seawater in advance before treating with a microbial filtration membrane can prevent clogging of the microbial filtration membrane and prevent a reduction in filtration capacity. This is preferable. That is, oil in seawater is also captured by the microbial filtration membrane, but unlike microorganisms and other turbid substances, if the oil adheres to the membrane surface, it cannot be easily removed by the above bubbling or backwashing process, It 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 the 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.

  Removal of oil in seawater is necessary to prevent contamination of the microbial filtration membrane, but it is preferable to remove turbidity in seawater in advance in order to reduce the load of microbial removal on the microbial filtration membrane. It does not restrict | limit especially as a method of removing the turbidity in seawater, A well-known turbidity removal apparatus can be used. Examples of the turbidity removal device include a sand filtration device, a device provided with a nonwoven fabric filter cloth made of polyethylene or polypropylene, a long fiber bundle turbidity removal device that adsorbs turbidity to a bundle of fibers erected in a filtration tank body, and the like. It is done. Use of an oil adsorbent “Diamarus (registered trademark)” is preferred in that both oil removal and turbidity can be removed.

Experimental example 1
The actual ballast water production apparatus installed on land shown in FIG. 3 was used without using an actual ship. That is, seawater (hereinafter referred to as “raw seawater”) in port A in Japan where the ship is anchored was pumped into the raw seawater tank of the experimental ballast water production apparatus, and this seawater was treated under the following operating conditions. The coliforms of raw seawater and treated water (membrane filtered water) were measured by the following measuring method. The oil content of the raw seawater was 8 mg / l as an n-hexane extract, and the turbidity of the raw seawater was 5 degrees.

(Experimental ballast water production system)
The apparatus shown in FIG. 3 was used. The experimental ballast water production apparatus 20 is mainly composed of a hollow fiber membrane type microbial filtration device 4a, and a hollow fiber membrane module 7 “STELLAPORE SUR31534” (Mitsubishi) comprising a microfiltration membrane with a treatment capacity of 3 m ³ / hour in a treatment tank 8. What dipped Rayon) was used. The raw seawater tank 11a and the hollow fiber membrane type microbial filtration device 4a are connected by a pipe 21 (28), and the hollow fiber membrane type microbial filtration device 4a and the backwash tank 6 are connected by a treated water pipe 42 and backwashed. An overflow pipe 38 was connected between the tank 6 and the treated water storage tank 16a. A suction pump 44 was installed in the treated water pipe 42. Further, a backwash pump 45 was installed so that the filtered water in the backwash tank 6 could be backwashed with the backwash pipe 43.

(how to drive)
The simulated one-pass processing method was used. That is, the raw seawater was supplied to the hollow fiber membrane type microbial filtration device 4a at a treatment rate of 3 m ³ / hour. In the microorganism removal step, air from the blower 46 is bubbled as fine bubbles from the distributor 41 installed in the lower part of the hollow fiber membrane module 7, and filtration is performed while removing microorganisms and the like adhering to the hollow fiber membrane surface. It was. Moreover, it was set as 1 minute of backwashing processes with respect to 15 minutes of microorganism removal processes, and this was repeated. Moreover, the waste liquid in which the microorganisms were concentrated was appropriately drained from the lower part of the treatment tank 8 of the hollow fiber membrane type microorganism filtration device 4a.

(Method for measuring microorganisms)
The coliform group was added to a BGLB medium (Brilliant Green Lactose Bile Broch) and cultured at 35 ° C. for 24 hours, and then the coliform group was counted.

(Processing result)
The number of coliforms in the raw seawater was 3500/100 ml, but no coliforms were detected in the treated water. Moreover, the n-hexane extract of the treated water was not detected, and the turbidity was 2 degrees or less. However, the differential pressure at a predetermined flow rate immediately after backwashing at the initial stage of the filtration operation was 0.01 MPa or less, but the differential pressure immediately after backwashing after 170 hours of filtration operation was 0.045 MPa.

Experimental example 2
The same procedure as in Experimental Example 1 was performed, except that the treatment was performed under the following experimental ballast water production apparatus and the following operating conditions.

(Experimental ballast water production system)
The apparatus shown in FIG. 4 was used. In the apparatus of FIG. 4, the same components as those of the apparatus of FIG. 3 are denoted by the same reference numerals, description thereof is omitted, and different points will be mainly described. That is, the apparatus of FIG. 4 is different from the apparatus of FIG. 3 in that an oil / water separator “Diamarus RH-03” having a processing capacity of 3 m ³ / hour is provided between the raw seawater tank 11a and the hollow fiber membrane type microorganism filtration apparatus 4a. (Mitsubishi Rayon Engineering Co., Ltd.) 5 is located.

(how to drive)
The simulated one-pass processing method was used. That is, the raw seawater was supplied to the hollow fiber membrane type microbial filtration device 4a at a treatment rate of 3 m ³ / hour. In the microorganism removal step, air was blown as fine bubbles from the distributor 41 installed in the lower part of the hollow fiber membrane module 7 and filtration was continued while peeling microorganisms and the like adhering to the surface of the hollow fiber membrane. . Moreover, it was set as the back washing process 1 minute with respect to the microorganism removal process 15 minutes, and this was repeated. Moreover, the waste liquid in which the microorganisms were concentrated was appropriately drained from the lower part of the treatment tank 8 of the hollow fiber membrane type microorganism filtration device 4a.

(Processing result)
The number of coliforms in the raw seawater was 3500/100 ml, but no coliforms were detected in the treated water. Moreover, the n-hexane extract of the treated water was not detected, and the turbidity was 2 degrees or less. The differential pressure at a predetermined flow rate immediately after backwashing at the initial stage of the filtration operation is 0.01 MPa or less, and the differential pressure immediately after backwashing after 170 hours of filtration operation is similarly 0.01 MPa or less. The oil content in the microfiltration membrane was effectively prevented by removing the oil content in the oil / water separator in advance.

Experimental example 3
Instead of the immersion type hollow fiber membrane type microbial filtration device 4a, a pressure type hollow fiber membrane type microbial filtration device (not shown) is used, and in the same manner as in Experimental Example 1, cleaning with bubbles and periodic backwashing steps are performed. went. However, the cleaning with bubbles was performed by bubbling with bubbles obtained by interrupting the water flow to the membrane treatment apparatus and injecting air from the lower part of the membrane for about 5 minutes. The hollow fiber membrane module used in the pressurization type hollow fiber membrane type microbial filtration apparatus is composed of three “Stelapore G type UMF-2024WFA” (manufactured by Mitsubishi Rayon Co., Ltd.), which is a microfiltration membrane with a processing capacity of 3 m ³ / hour. Using. In addition, an oil / water separator “Diamarus RH-03” having a treatment capacity of 3 m ³ / hour was disposed in the front stage of the hollow fiber membrane type microorganism filtration device.

(Processing result)
The number of coliforms in the raw seawater was 3500/100 ml, but no coliforms were detected in the treated water. Moreover, the n-hexane extract of the treated water was not detected, and the turbidity was 2 degrees or less. The differential pressure data of the microfiltration membrane was the same as in Experimental Example 2.

  As shown in each example, the raw seawater stored in the raw seawater tank was processed with a ballast water production apparatus, and thus the coliforms in the raw seawater were removed to the extent that they were not detected. In addition, by installing an oil-water separator in front of the hollow fiber membrane type microorganism filtration device, it was possible to effectively prevent contamination of the microfiltration membrane due to oil.

(A) is the schematic cross section cut along the direction orthogonal to the bow stern direction of the hull, (B) is the schematic cross section cut along the bow stern direction of the hull. It is a flowchart of the ship mounted ballast water manufacturing apparatus of this example. It is a flowchart of the experimental ballast water manufacturing apparatus used in Experimental example 1. It is a flowchart of the experimental ballast water manufacturing apparatus used in Experimental example 2.

Explanation of symbols

1 Ship (ballast structure of tanker)
DESCRIPTION OF SYMBOLS 2 Ballast water tank 4 Microbial filtration membrane apparatus 4a Hollow fiber membrane type microorganism filtration apparatus 5 Oil content adsorption removal apparatus 6 Backwash tank 7 Hollow fiber membrane module 8 Treatment tank 10 Ship mounted ballast water production apparatus 11-16 Ballast water tank 11a Raw seawater 20, 30 Experimental Ballast Water Production Equipment 21-26 Seawater Supply Pipe 31-36 Membrane Filtration Water Supply Pipe 28 Seawater Inflow Pipe 38 Membrane Filtration Water Outflow Pipe 41 Distributor 43 Backwash Pipe 44 Suction Pump 45 Backwash Pump 46 Blower

Claims (9)

  A microbial removal step of removing microorganisms in seawater by passing seawater loaded on the ship through a microbial filtration membrane on the vessel, and a backwashing step of washing the microbial filtration membrane by backwashing, A method for producing ballast water, wherein the membrane filtrate obtained is used as ballast water.   The seawater is respectively loaded in a plurality of ballast tanks in a ship, and the microorganism removal step passes the seawater of one ballast tank through a microorganism filtration membrane, and uses the obtained membrane permeated water as the one ballast tank. The method for producing ballast water according to claim 1, wherein the processing is performed sequentially for seawater in other ballast water tanks.   The seawater is one of a plurality of ballast tanks in a ship, and one of the ballast tanks is loaded into another ballast tank, and the microorganism removal step passes the seawater of one ballast tank through a microorganism filtration membrane. The one ballast tank that performs the one-pass process of supplying the obtained membrane permeated water to the empty water tank, then passes the seawater of another ballast water tank through the microbial filtration membrane, and the obtained membrane permeated water becomes the empty water tank. The method for producing ballast water according to claim 1, wherein a one-pass process is performed, and the one-pass process is sequentially performed.   The method for producing ballast water according to any one of claims 1 to 3, wherein at least oil in seawater is removed in advance before the treatment with the microorganism filtration membrane.   The said microbial filtration membrane is a hollow fiber membrane, The manufacturing method of the ballast water of any one of Claims 1-4 characterized by the above-mentioned.   The method for producing ballast water according to any one of claims 1 to 5, wherein oil in the seawater is adsorbed and removed with a hydrophobic adsorbent.   A plurality of ballast water tanks loaded with pumped seawater, a microbial filtration membrane device for removing microorganisms in seawater stored in the ballast water tank, and a backwash for storing membrane filtered water obtained by the microbial filtration membrane device A ship-mounted ballast comprising a tank, a seawater supply pipe connecting each of the ballast water tanks and the microbial filtration membrane device, and a membrane filtered water supply pipe connecting the backwash tank and the respective ballast water tanks Water production equipment.   8. The ship-mounted ballast water producing apparatus according to claim 7, wherein an oil adsorption / removal device that removes at least oil in seawater is installed upstream of the microorganism filtration membrane device and downstream of the ballast water tank. The ship-mounted ballast water production apparatus according to claim 7 or 8, wherein the microorganism filtration membrane device is an immersion type hollow fiber membrane device or a pressure type hollow fiber membrane device.

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