JP2011062682A - Ballast water producing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ballast water producing apparatus capable of returning plankton inhabiting sea water overboard without damage as far as possible and also capable of reducing treatment cost and employing a small-sized structure. <P>SOLUTION: The ballast water producing apparatus includes a filtration unit 4 comprising a depth filter 10 and a housing 9 for housing the depth filter 10 for filtering raw water RW and a chemical treatment unit 3 for supplying calcium hypochlorite into filtered water FW filtered by the filtration unit 4. The housing 9 has a raw water supply port 18 for supplying the raw water RW to the depth filter 10, a filtered water FW outlet port 16 for delivering the filtered water FW, a fluid supply port 24 for supplying compressed air A for backwashing to the depth filter 10, and an outlet port 14 for discharging the raw water RW and the compressed air A which have backwashed the depth filter 10, with the pore diameter of the depth filter 10 ranging from 1 to 25 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an apparatus for producing ballast water mounted on a ship such as a cargo ship.

  For example, when a ship, particularly a cargo ship, is not loaded, a measure is taken to stabilize the hull by loading seawater or the like into a ballast tank provided in the ship in order to lower the center of gravity of the ship. Ballast water is discharged out of the ship when loading cargo at the port where it stops, but on ocean-going ships, aquatic organisms contained in the ballast water travel between countries and point out problems that affect ecosystems as alien species. Has been.

  In recent years, in order to solve such problems related to ballast water, international efforts have been made for ballast water discharge regulations. Specifically, it regulates the number of plankton (mainly zooplankton), 10 to 50 μm plankton (mainly phytoplankton) and fungi (E. coli, enterococci, etc.) contained in ballast water. is there. Treatment methods to satisfy these regulations usually combine filtration, mechanical treatment such as cavitation that kills plankton by high-speed, high-pressure jet flow, and chemical treatment that uses chemicals, ozone, etc. (For example, Non-Patent Document 1).

Maritime General Magazine Bimonthly Compass September 2007, pages 32-39

  In the conventional ballast water production apparatus described above, the pore size of the filter for filtration is about 50 μm which is relatively large. This is because clogging is likely to occur when the hole diameter is small, and it is necessary to increase the filtration area of the filter in order to avoid this, so that the apparatus becomes large and disadvantageous for mounting the ship. Therefore, plankton having a size of 50 μm or less is treated by cavitation in which seawater is sprayed on the screen at high speed and high pressure to crush plankton, or by drug administration.

  However, in the treatment by cavitation, seawater is blown at high speed and high pressure, so the power becomes excessive and the number of plankton is reduced more than necessary, which may affect the marine ecosystem on the ballast water loading side. is there.

  In addition, in the method of adding chlorine and sodium hypochlorite to generate hypochlorous acid and processing plankton, not only a large amount of drug is required to kill plankton, When discharging ballast water to the ocean, it is necessary to neutralize it by administering a reducing agent such as sodium thiosulfate, which is environmentally burdensome and increases the cost of each treatment.

  The present invention has been made in view of the above problems, and is capable of returning to the outside of the ship without damaging plankton living in the sea as much as possible, and is a small ballast water production apparatus that can keep processing costs low. The purpose is to provide.

  In order to achieve the above object, a ballast water production apparatus according to the present invention includes a filter medium and a housing that accommodates the filter medium, a filtration unit that filters raw water, and a solid sub-phase in the filtrate filtered by the filtration unit. A ballast water production apparatus comprising a chemical treatment unit for feeding calcium chlorate, wherein the housing includes a raw water supply port for supplying raw water to the filter medium, an outlet for filtered water, and backwashing the filter medium. A fluid supply port for supplying a fluid for use, a fluid for backwashing the filter medium and a discharge port for discharging the raw water, and the filter medium is a depth filter having a pore diameter of 1 to 25 μm. As the fluid for backwashing, a gas or a liquid is used, preferably a gas, and more preferably an inert gas such as air or nitrogen.

The pore diameter is defined as follows. Particles having a constant diameter, preferably spherical polystyrene or glass beads added at 10000 particles / L in water, are added to a depth filter (outer diameter 60 mm, inner diameter 30 mm, length 250 mm) at 25 ° C. and 1.0 m ³ / h. The number of particles that passed through the depth filter was measured with an optical counter, and the difference in the number of particles present in the liquid before and after the water flow was divided by the number of particles present in the liquid before the water flow. The obtained collection rate (R%) is measured for a plurality of particles, and the value of the diameter (S) of the particles with R of 80 is obtained in the following approximate expression (1) based on the measured values. Is the hole diameter.
R = 100 / (1−m × exp {−a × log (S)}) (1)
Here, m and a are constants determined by the properties of the depth filter.
For example, when the diameter of the particles is 1 μm, the liquid added with spherical polystyrene fine particles (10,000 particles / L) is passed through a depth filter (outer diameter 60 mm, inner diameter 30 mm, length 250 mm) under the above conditions. Measurement is possible.

  According to this configuration, since the depth filter is used for the filter medium, the initial introduction cost can be reduced as compared with the case where the surface filter is used. In addition, by performing reverse flow cleaning, the filtration performance of the filter medium can be recovered and used, so the frequency of replacement of the filter medium can be reduced, and maintenance costs can be reduced. Furthermore, since the pore diameter of the depth filter is 1 to 25 μm, it can be captured and discharged out of the ship with most plankton alive, and the marine ecosystem on the ballast water loading side is not destroyed. This eliminates the need for cavitation and chemical administration to treat plankton, so less power is consumed and less calcium hypochlorite is used. A summing process is also unnecessary. As a result, a small system with a low processing cost can be constructed.

  In the present invention, the chemical treatment unit generates a container containing solid calcium hypochlorite and a concentrated solution in which the solid calcium hypochlorite taken out from the container is dissolved in the filtered water. A unit for treating microorganisms with hypochlorous acid is preferable. According to this configuration, since solid calcium hypochlorite is used, unlike liquid drugs, transportation is easy and economical regardless of land and sea, and restrictions on transportation regulations are eased. . In addition, since calcium hypochlorite has a high melting point, it can be easily stored even in a ship that tends to be hot. Furthermore, since it is solid, the volume is small and the storage space is small. At the same time, the apparatus itself can be miniaturized, which is advantageous when it is installed in a limited space on board.

  In the present invention, the chemical treatment unit dissolves the solid calcium hypochlorite in a part of the filtered water taken out from the water supply passage for supplying the filtrate, and merges it with the filtered water in the water supply passage. It is preferable that a throttle means for reducing the flow rate of the filtered water in the water supply passage is provided between the branch point and the merge point. According to this configuration, the excess filtered water due to the reduced flow rate is supplied to the solid calcium hypochlorite from the branch point, so that a supply means such as a dedicated pump is not required, and the configuration is In addition to being simple, it can reduce power requirements. Instead of the throttling means, a small-capacity small injection pump may be provided to take out a part of the filtrate from the water supply passage.

  In the present invention, the solid calcium hypochlorite is preferably stored in a sealed container. According to this structure, it is suppressed that the smell of chlorine leaks into the ship. In addition, when replacing the solid calcium hypochlorite, it is only necessary to replace the entire container, so that the calcium hypochlorite does not come into direct contact with people or the air in the ship.

  In this invention, it can also arrange | position so that the said filter medium may incline at the inclination angle of 20-70 degrees diagonally upward toward the said filtrate water extraction opening. According to this configuration, since the opening end of the depth filter located on the filtered water outlet side opens obliquely upward, air near the closed end of the lower depth filter escapes from the opening end. Air can be prevented from remaining in the interior, and the entire depth filter can be used for efficient filtration.

  The method for producing ballast water according to the present invention is a ballast water production method using the ballast water production apparatus of the present invention, and the supply of filtered water from the filter medium to the ballast tank and the supply of fluid to the filter medium are stopped. In a state, the raw water is supplied to the filtration unit in a state where the preparation process of discharging the fluid together with the raw water from the outlet through the filtration unit, and the discharge of the raw water from the filter medium and the fluid supply to the filter medium are stopped, While supplying the filtered water to the filtration medium and supplying the filtered water to the ballast tank, while supplying the raw water to the filter medium, the fluid is supplied from the filtered water side to the filter medium. And a backwashing process for discharging the raw water from the discharge port to the outside of the ship through the discharge passage. The treated water treated by the filtration unit passes through the calcium hypochlorite unit, and fungi (such as E. coli and enterococci) are removed.

  According to this configuration, plankton living in the sea can be returned to the outside of the ship without damaging it as much as possible, and the processing cost can be kept low with a small size. In addition, since raw water is always supplied to the filtration unit, it is possible to avoid sudden pressure fluctuations in the passage and to prevent occurrence of water hammer. Furthermore, since the raw water is supplied to the filtration unit in the backwashing process, the backwashing fluid can be smoothly drained without flowing back to the raw water supply side.

  According to the ballast water production apparatus of the present invention, by performing backflow cleaning, the filtration performance of the filter medium can be recovered and used, and maintenance costs can be reduced. In addition, since the raw water is always supplied to the filtration unit even during the backwashing, the backwashing fluid can be smoothly drained without flowing back to the raw water supply side. In addition, most plankton can be captured without damaging the marine ecosystem on the ballast water loading side, and power consumption and calcium hypochlorite consumption can be reduced. A neutralizing agent for returning ballast water to seawater is also unnecessary. As a result, a small system with a low processing cost can be constructed.

It is a systematic diagram of the ballast water manufacturing apparatus provided with the filtration unit concerning a 1st embodiment of the present invention. It is an expanded sectional view of a filtration unit same as the above. It is a driving | operation process table | surface of a filtration system same as the above. It is a systematic diagram of the chemical treatment unit in the ballast water manufacturing apparatus concerning a 2nd embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic system diagram of a ballast water production apparatus for a ship provided with a filtration unit according to the first embodiment of the present invention. The ballast water production apparatus 1 is installed in the ship S, and is filtered by the ballast pump 2 that takes the raw water RW into the ship S, the filtration unit 4 that filters the raw water RW taken into the ship, and the filtration unit 4. And a chemical treatment unit 3 for feeding calcium hypochlorite into the filtered water FW. The filtration unit 4 includes a raw water passage 5 to which the raw water RW is supplied by the ballast pump 2, a water supply passage 8 for supplying the filtrate FW from the filtration unit 4 to the ballast tank 6 installed in the ship S, and a filtration unit 4 is connected to a discharge passage 14 for discharging raw water RW together with compressed air A, which will be described later, to the outside of the ship, and a water supply passage 8 is connected to a fluid supply passage 12 for supplying the compressed air A to the filtration unit 4. Further, an air vent passage 19 connected to the discharge passage 14 is connected to a filtrate outlet 16 (described later) to which the water supply passage 8 is connected to the filtration unit 4. Thereby, with respect to the existing ballast water production apparatus already mounted on the ship S, the filtration unit is replaced with the filtration unit 4 of the present invention, and the fluid supply passage 12 is further connected to the existing water supply passage. The present invention can be easily applied to this ballast water production apparatus.

  Each passage 5, 8, 12, 14, 19 is formed by piping. The filtration unit 4 houses a depth filter 10 which is a filter medium forming a filtration membrane in a cylindrical housing 9. In the present embodiment, the ballast pump 2 is mounted on the ship, but may be provided outside the ship, for example, may be installed in a port.

  The raw water passage 5 is connected to a first automatic opening / closing valve MV1 that functions as a raw water supply valve, and a primary pressure is provided between the first automatic opening / closing valve MV1 and the filtration unit 4 in the raw water passage 5, that is, on the primary side of the filtration unit 4. A sensor P1 is provided. The water supply passage 8 is connected to a second automatic opening / closing valve MV2 that functions as a water supply valve for the filtered water FW, and between the second automatic opening / closing valve MV2 and the filtration unit 4 in the water supply passage 8, that is, the secondary side of the filtration unit 4. Is provided with a secondary pressure sensor P2.

  Furthermore, the chemical treatment unit 3 is provided on the upstream side of the ballast tank 6 in the water supply passage 8. The chemical treatment unit 3 treats plankton and fungi remaining in the filtered water FW filtered by the filtration unit 4 with calcium hypochlorite, and has a container 26 in which solid calcium hypochlorite is stored. ing.

  The container 26 is a sealed container that contains solid calcium hypochlorite. The chemical treatment unit 3 further branches a part of the filtered water FW from the branch point 8a of the water supply passage 8 and supplies the filtered water FW to the container 26, and solid calcium hypochlorite in the container 26. It has a confluence passage 17 for joining the dissolved concentrated liquid to a confluence 8b downstream of the branch point 8a in the water supply passage 8. Part of the filtered water FW enters the container 26 through the branch passage 15 and gradually dissolves the solid calcium hypochlorite while passing between the granular solid calcium hypochlorite stored in the container 26. It becomes a high concentration hypochlorous acid solution. Thereby, for example, a calcium hypochlorite concentrate having a concentration of 90% with respect to the saturation concentration is obtained, and this concentrates with the filtrate FW in the water supply passage 8 through the junction passage 17. The combined filtrate FW and hypochlorous acid concentrate are stirred and homogenized by the mixer 28 provided in the water supply passage 8 to treat plankton, fungi, and the like remaining in the filtrate FW.

  Between the branch point 8a and the junction point 8b, a throttle means 25 such as an orifice for reducing the flow rate of the filtered water FW passing through the water supply passage 8 is provided. Since the throttle means 25 reduces the passage area, the pressure at the inlet of the throttle means 25 becomes higher than the pressure at the outlet. The pressure difference is preferably about 1 to 10 kPa. Due to this pressure difference, a part of the filtrate FW at the branch point 8 a on the high pressure side flows into the branch passage 15 and is returned to the junction 8 b on the low pressure side via the container 26 and the junction passage 17. Therefore, a pump for supplying the filtered water FW from the water supply passage 8 to the container 26 is unnecessary.

  The confluence passage 17 is provided with a sixth automatic adjustment valve MV6 for adjusting the flow rate of the concentrate, and a residual chlorine meter M for measuring the residual chlorine concentration in the filtrate FW is provided downstream of the mixer 28 in the water supply passage 8. The residual chlorine concentration in the filtrate FW is controlled to be a set value by adjusting the flow rate of the concentrate with the sixth automatic adjustment valve MV6. The driving of the sixth automatic opening / closing valve MV6 is controlled by the controller 30. As the sixth automatic opening / closing valve MV6, an air drive valve, an electric valve, an electromagnetic valve, a manual valve that does not use a controller, or the like is used.

  The fluid supply passage 12 is connected to a third automatic opening / closing valve MV3 that acts as a compressed air introduction valve, and the drainage passage 14 is connected to a fourth automatic opening / closing valve MV4 that acts as a drainage valve. Is connected to a fifth automatic on-off valve MV5 which acts as an air vent valve. One end of the fluid supply passage 12 is connected to an air compressor (not shown), and the other end is connected to the secondary side below the filtration unit 4. Note that the other end of the fluid supply passage 12 may be connected to the vicinity of the filtration unit 4 in the water supply passage 8, more specifically, between the filtration unit 4 and the secondary pressure sensor P2. Driving of the ballast pump 2 and the first to sixth automatic opening / closing valves MV <b> 1 to MV <b> 6 is controlled by the controller 30. The outputs of the primary pressure sensor P1, the secondary pressure sensor P2, and the residual chlorine meter M are input to the controller 30.

  As the air compressor, one installed on the ship for another purpose may be used, or a dedicated one may be installed. In addition, as each of the automatic opening / closing valves MV1 to MV6, an air drive valve, an electric valve, an electromagnetic valve, a manual valve that does not use a controller, or the like is used.

  The depth filter 10 has a hollow cylindrical shape with one end opened and the other end closed with a closing member 13, and the hollow end of the depth filter 10 is directed toward the filtered water outlet 16 with the opening end 10 a being one end thereof. 11 is communicated with the filtered water outlet 16. When the raw water RW passes through the depth filter 10 in the radial direction, foreign matters are captured by the pores inside the filter, and filtered water FW is obtained. The depth filter 10 is also detachably housed in the housing 9 of the filtration unit 4 so that the open end 10a is above the closed end 10b which is the other end, that is, the filtration unit 4 is connected to the filtered water outlet. It is arrange | positioned so that it may incline diagonally upward toward 16. FIG. The inclination angle α, which is an angle formed by the center line C in the longitudinal direction of the depth filter 10 and the horizontal plane H, is preferably 20 to 70 °, and more preferably 30 to 60 °.

  As shown in FIG. 2, which is an enlarged cross-sectional view of the filtration unit 4, a cylindrical casing 9 of the inclined filtration unit 4 is composed of a lower end wall 9a, a peripheral wall 9b, and an upper end wall 9c. Thus, the shaft center C is inclined so as to be inclined obliquely upward from the one end wall 9a toward the other end wall 9c. A discharge port 22 connected to the discharge passage 14 is connected to the one end wall 9a of the housing 9, and a raw water supply port 18 connected to the raw water passage 5 is connected to the raw water passage 5 in the vicinity of the one end wall 9a of the peripheral wall 9b. A fluid supply port 24 connected to the fluid supply passage 12 and a filtered water outlet 16 connected to the water supply passage 8 are formed. The filtered water outlet 16 is disposed at the uppermost portion in the circumferential direction of the inclined peripheral wall 9b.

  An annular bottom plate 9d is provided below the fluid supply port 24 and the filtrate outlet 16 in the peripheral wall 9b of the housing 9 in the axial direction, and the open end 10a of the depth filter 10 is supported by the bottom plate 9d. That is, a space S is formed between the other end wall 9c and the bottom plate 9d in the housing 9, and the fluid supply port 24, the filtrate outlet 16 and the open end 10a of the depth filter 10 face the space S. The hollow portion 11 of the depth filter 10 and the space S communicate with each other. The depth filter 10 concentric with the housing 9 is also inclined, and is arranged so that the open end 10a is above the closed end 10b. The raw water supply port 18 and the discharge port 22 are provided on the primary side of the depth filter 10, and the filtered water outlet 16 is provided on the secondary side.

  The depth filter 10 is an external pressure type cylindrical filter and has a U-shaped longitudinal section. Examples of the depth filter 10 include what is called a laminated type in which synthetic fibers or chemical fibers are welded / formed in the form of a web, non-woven fabric, paper, woven fabric or the like and processed into a cylindrical shape. As the synthetic fiber, polyolefin, polyester, heat-meltable polymer such as nylon or ethylene vinyl alcohol copolymer, or polymer such as polyvinyl alcohol or polyacrylonitrile can be used. Among these, when backflow cleaning with gas is performed, polyolefin and polyester, specifically, polypropylene are preferable from the viewpoint of liquid drainage at the time of filter replacement. The filter preferably has a structure in which the fiber density and fineness are changed in the thickness direction, and the fiber density is low or the fineness is large on the outside (raw water inflow side) of the filter. The depth filter 10 includes a so-called thread wound filter in which filaments and spun yarns are spirally wound, and a so-called resin molded type that is a resin molded body such as a sponge.

  The pore diameter of the filtration membrane is preferably 1 to 25 μm, more preferably 1 to 15 μm, and further preferably 1 to 10 μm. If the pore diameter is too small, clogging occurs and pressure loss increases. If the hole diameter is too large, small plankton will pass through, and in order to reduce this, additional means such as cavitation is required, which increases the cost of producing ballast water.

  The depth filter 10 can be backwashed in the filtration unit 4 and can be used without increasing the differential pressure during filtration by recovering the filtration performance by backwashing. In this embodiment, backwashing is performed by compressed air A supplied from a compressor (not shown) through the fluid supply passage 12 (FIG. 1), and the supply pressure of the compressed air A from the fluid supply port 24 is The pressure is 0.05 to 0.2 MPa higher than the indicated pressure of the primary pressure sensor P1. The fluid used for backwashing may be a gas other than air, such as nitrogen, or a liquid such as fresh water or filtered seawater.

  Next, an operation method of the ballast water production apparatus, that is, a filtered water production method and a calcium hypochlorite treatment method using the filtration unit according to the present embodiment will be described with reference to FIGS. 1 and 3. As shown in FIG. 3, the operation method of the ballast water production apparatus includes an air venting process, a first switching process, a filtering process, a second switching process, a third switching process, and a backwashing process, which are preparatory processes for filtration.

  When the ballast water production apparatus 1 is operated by operating a start button (not shown) installed in the controller 30, the ballast pump 2 is first activated to open the first automatic open / close valve MV1 and the fifth automatic open / close valve MV5. To enter the air venting process. In the air venting process, the second automatic open / close valve MV2, the third automatic open / close valve MV3, and the fourth automatic open / close valve MV4 are closed, and the filtered water FW is supplied from the depth filter 10 to the ballast tank 6 and compressed to the depth filter 10. With the supply of air A stopped, the filtered water FW flows from the filtered water outlet 16 of the filtration unit 4 through the air vent passage 19 to the discharge passage 14 and is discharged to the outside of the ship. Air release of unit 4 is performed. Since the filtrate outlet 16 is located near the uppermost part of the filtration unit 4, the air in the filtration unit 4 is smoothly discharged from the filtrate outlet 16 to the air vent passage 19.

  Next, the second automatic opening / closing valve MV2 is opened to enter the first switching step. In a 1st switching process, in the state which stopped supply of the compressed air A to the depth filter 10, the filtered water FW is supplied to the discharge passage 14 and the water supply passage 8 through the filtration unit 4, respectively.

  Subsequently, the fifth automatic opening / closing valve MV5 is closed and the filtration process is started. In the filtration step, the raw water RW is supplied to the filtration unit 4 while the drainage from the depth filter 10 and the compressed air supply to the depth filter 10 are stopped, and the filtrate FW is sent to the water supply passage 8. At this time, the raw water RW passes through the filtration membrane of the depth filter 10 from the outside of the depth filter 10 and flows into the hollow portion 11, thereby removing foreign substances in the raw water RW and filtering. A part of the filtrate FW is supplied to the chemical processing unit 3 through the branch passage 15.

  In the chemical treatment unit 3, the filtered water FW into which calcium hypochlorite has been charged is returned to the water supply passage 8 at the junction 8 b, merged with the filtered water FW, stirred by the mixer 28, and supplied to the ballast tank 6. The

  Next, the fourth automatic opening / closing valve MV4 is opened to enter the second switching step. In the second switching step, in a state where the supply of the compressed air A to the depth filter 10 is stopped, the raw water RW is supplied to the filtration unit 4 so that the filtered water FW flows through the water supply passage 8 and the raw water RW is discharged into the discharge passage 14. Shed.

  Subsequently, the second automatic opening / closing valve MV2 is closed and the third switching step is entered. In the third switching step, the raw water RW is caused to flow through the discharge passage 14 in a state where supply of the filtered water FW from the depth filter 10 to the ballast tank 6 and supply of the compressed air A to the depth filter 10 are stopped. In this way, the supply of the filtrate FW from the depth filter 10 is stopped to prepare for the start of the supply of the compressed air A in the direction opposite to the flow direction of the filtrate FW in the next backwashing step.

  Next, with the second automatic opening / closing valve MV2 closed, the third automatic opening / closing valve MV3 is opened and the back washing process is started. In the backwashing process, the compressed air A is supplied to the hollow portion 11 of the depth filter 10 while supplying the raw water RW to the filtration unit 4 while the supply of the filtered water FW to the ballast tank 6 is stopped. The air A is passed through the discharge passage 14 together with the raw water RW. As a result, the compressed air A passes through the depth filter 10 in the direction opposite to that of the filtration step, and the foreign matter adhering to the depth filter 10 and the foreign matter accumulated in the housing 9 are led out of the filtration unit 4, and the discharge passage 14 To the outside of the ship S.

  When the backwash process is completed, the third automatic open / close valve MV3 and the fourth automatic open / close valve MV4 are closed, the fifth automatic open / close valve MV5 is opened, and the process returns to the air venting process. Thereafter, this loop is repeated. The duration of the bleed process is variably set by a time limit device such as a timer. The set time varies depending on the scale of the processing equipment, but is, for example, about several seconds to 1 minute. The first, second, and third switching steps are for a very short time, for example, about several seconds, and are also variably set by a timing device such as a timer. Thus, it is possible to avoid sudden pressure fluctuations in the passage by passing through the first, second and third switching steps before entering the filtration step and the backwashing step. Although the time of a filtration process and a backwash process changes with the water quality of raw | natural water and the scale of an installation, it is about 10 minutes, for example, and this is also variably set by a time limit apparatus like a timer. The transition from the filtration step to the second switching step may be performed when the differential pressure ΔP (= P1−P2) between the primary pressure sensor P1 and the secondary pressure sensor P2 becomes larger than a specified value. .

  During the filtration process, the controller 30 constantly monitors the differential pressure ΔP and the residual chlorine concentration. If the differential pressure ΔP or the residual chlorine concentration exceeds the alarm value H1, an alarm such as a buzzer is issued to call attention. . At this time, the water treatment apparatus 1 continues to operate. Further, when the differential pressure ΔP or the residual chlorine concentration increases and exceeds the emergency stop value H2, an alarm such as a bell is issued, and the water treatment apparatus 1 is urgently stopped. Specifically, the controller 30 stops the ballast pump 2 and closes all the automatic opening / closing valves MV1 to MV6.

  Sudden changes in pressure and flow velocity not only damage plankton, but also cause water hammer in the parastump pump 2, each automatic on-off valve MV1-6, and each passage 5, 8, 12, and 14. However, as in the operation method of FIG. 3, the ballast pump 2 is always operated and the supply of the raw water RW from the ballast pump 2 is not stopped, and the opening / closing timing of each of the automatic opening / closing valves MV1 to MV5 is adjusted. As a result, mild driving can be performed. Further, since the backwashing is performed while the raw water RW is flowing, drainage can be smoothly performed by the discharge pressure of the ballast pump 2 and the air pressure of the compressed air A, and a separate drain pump and drain pipe are not required, and the system can be simplified.

  In the above configuration, since the pore diameter of the filtration membrane forming the depth filter 10 is 1 to 25 μm, it is possible to capture most of the plankton while suppressing pressure loss due to clogging of the filter, and to load the ballast water In addition to not destroying the marine ecosystem on the side, there is no need to perform cavitation and large doses of drugs to treat plankton as in the past, so power consumption and usage of drugs can be reduced, A neutralization step with a reducing agent when returning ballast water to seawater is also unnecessary. As a result, it is possible to construct a ballast water production apparatus that is small and inexpensive. Moreover, since the depth filter 10 is back-washed, the filtration performance of the depth filter 10 can be recovered and used, and processing costs can be further reduced. Furthermore, since the inexpensive depth filter 10 is used, the initial introduction cost can be reduced as compared with the case of using a surface filter that captures foreign matters on the filter surface such as a flat membrane.

  Moreover, since the chemical processing unit 3 uses solid calcium hypochlorite, it is easy to transport unlike the liquid medicine. In addition, since calcium hypochlorite has a high melting point, it can be easily stored even in a ship that tends to be hot.

  Furthermore, a throttle means 25 for reducing the flow rate of the filtrate FW is provided between the branch point 8a and the junction 8b of the water supply passage 8, and the excess filtrate water FW resulting from the reduction of the flow rate is provided. Since it is supplied from the branch point 8a to the container 26 containing solid calcium hypochlorite, a supply means such as a dedicated pump is unnecessary, the configuration is simplified, and the necessary power can be reduced. .

  Moreover, since solid calcium hypochlorite is stored in the sealed container 26, leakage of chlorine odor into the ship is suppressed. Furthermore, when replacing the solid calcium hypochlorite, the container 26 only needs to be replaced, so that the calcium hypochlorite does not come into direct contact with people or the air in the ship.

  Furthermore, since the opening end 10a of the depth filter 10 is opened obliquely upward, when switching from the backwashing process to the air bleeding process, air near the closed end 10b of the depth filter 10 escapes from the opening end 10a. It is possible to prevent the air from remaining in the depth filter 10 and to efficiently perform filtration using the entire depth filter 10 in the filtration process. If the inclination angle α with respect to the horizontal direction is too large, the vertical dimension of the filtration unit 4 becomes large. Therefore, when performing maintenance such as removal, a large space for extracting the depth filter 10 above the filtration unit 4 is required. If it is too small, the air A in the vicinity of the closed end 10b in the filtration unit 4 is difficult to escape. Therefore, this inclination angle α is preferably 20 to 70 °.

  Furthermore, according to the above operation method, as shown in FIG. 3, the ballast pump 2 is always in operation during the system operation, that is, the raw water RW is always supplied to the filtration unit 4, so Sudden pressure fluctuations can be avoided and the occurrence of water hammer can be prevented. Further, since the raw water RW is also supplied to the filtration unit 4 in the backwashing process, the raw water flow is not caused to flow back into the raw water passage 5 by the supply pressure of the compressed air A and the supply pressure of the raw water RW. Can be drained smoothly on top.

  In addition, unlike a surface filter that collects the material to be filtered only on the surface of the filter, the depth filter can collect the material to be filtered in the entire thickness direction of the filter. There is no time clogging.

  FIG. 4 is a system diagram of the chemical treatment unit 3A in the ballast water production apparatus according to the second embodiment. In the second embodiment, the chemical processing unit 3 of the first embodiment is replaced with a chemical processing unit 3A, and other configurations are the same as those of the first embodiment. About the same structure as 1st Embodiment, the code | symbol same as FIG. 1 is attached | subjected and description is abbreviate | omitted. In the first embodiment, the entire amount of granular solid calcium hypochlorite to be used is dissolved at a time. However, in the chemical processing unit 3A in FIG. Most of the powder is stored in the hopper 50 in a granular form, and a part measured by the measuring tube 51 is appropriately dissolved in the dissolution tank 53. In this embodiment, the measuring tube 51 has a weight sensor (not shown) so that it can detect that the granular solid calcium hypochlorite has reached a desired weight. The configuration of the measuring tube 51 is not limited to this, and may be one that detects that a predetermined volume has been reached, for example. A lower part of the hopper 50 and a measuring pipe 51 below the hopper 50 are connected via a first valve 54, and a measuring pipe 51 and a dissolving tank 53 below the hopper 50 are connected via a second valve 55.

  In the second embodiment, the hopper 50 is filled with a large amount (eg, 1000 g) of granular solid calcium hypochlorite, the first valve 54 is opened at an arbitrary timing, and the granular solid hypochlorous acid is added to the measuring tube 51. Calcium is introduced. A measuring tube 51 measures a necessary amount (for example, 45 g) of granular solid calcium hypochlorite, and after the first valve 54 is closed, the second valve 55 is opened, and the dissolving tank 53 has a necessary amount of the granular solid hypochlorite. Calcium chlorite is introduced. After the introduction, the second valve 55 is closed. Filtrated water FW flows into the dissolution tank 53 through the branch passage 15 branched from the water supply passage 8, and the granular solid calcium hypochlorite is filtered by stirring with a stirrer 56 provided in the dissolution tank 53. It is dissolved in water FW to produce calcium hypochlorite with a high concentration (eg, 3000 mg / L), merged into the water supply passage 8 via the merge passage 17, and then stirred in the mixer 28, for example effective. Treated water with a chlorine concentration of 1 mg / L is prepared. In this embodiment, the timing at which granular solid calcium hypochlorite is charged, that is, the timing at which the first valve 54 is opened is determined by the numerical value of the residual chlorine meter M. However, it is set by a timing device such as a timer. Alternatively, other means may be used.

  According to the second embodiment, the same effect as that of the first embodiment is produced, and only a necessary amount of the high concentration calcium hypochlorite solution is produced, so that the high concentration calcium hypochlorite solution is dissolved. It does not stay in the tank 53 for a long time, and the corrosion of the dissolution tank 53 is reduced. Furthermore, since the hopper 50 is provided in a complete dry space, it is easy to replenish granular solid calcium hypochlorite.

Examples 1-5, Comparative Examples 1-2
A verification experiment was performed using the depth filter 10 in the present embodiment. The depth filter used was a hollow cylinder having a length of 250 mm, an outer diameter of 60 mm, and an inner diameter of 30 mm, and the pore diameters were 1 μm (Example 1), 3 μm (Example 2), 10 μm (Example 3), and 15 μm (Example 4). ), 25 μm (Example 5), 30 μm (Comparative Example 1), and 50 μm (Comparative Example 2), and the shaft center of the depth filter was inclined by 45 ° with respect to the horizontal plane. As raw water, 1L per zooplankton (smallest part is more than 50 [mu] m) to 3.0 × 10 ² pieces, also the phytoplankton per 1 cc (size 8~12μm) 1.5 × 10 ⁴ pieces containing seawater (water temperature 25 ° C.) at a flow rate of 25 L / min, and the number of plankton present in the filtrate was measured. The results are shown in Table 1.

  In Examples 1 to 5, almost all zooplankton was removed, but 20% or more of Comparative Example 1 and 40% of zooplankton remained in Comparative Example 2. Also, phytoplankton was almost removed in Example 1, 99% or more in Example 2, about 99% in Example 3, 96% or more in Example 4, and about 5% in Example 5. 92% of each was removed. On the other hand, 60% or more remained in Comparative Example 1, and 90% or more remained in Comparative Example 2.

  Subsequently, a concentrated solution in which a predetermined amount of granular calcium hypochlorite was added to 1000 L of seawater was prepared, and this was adjusted to the effective chlorine concentrations shown in Table 2, Examples 1 to 5 in Table 1 and Comparative Examples It added to the filtered water filtered with the 1-2 depth filter. The effective chlorine concentration was measured with an absorptiometer (Shimadzu UV-1700) after color development using a DPD reagent. Water treated with calcium hypochlorite measures the number of plankton living under a microscope, measures the number of E. coli by culturing at 25 ° C. for 7 days in an XM-G medium, and further uses the MarineAgar medium. The number of heterotrophic bacteria was measured under the same conditions. The results are shown in Table 2.

  In Examples 1 to 3, E. coli and heterotrophic bacteria were not detected even when the effective chlorine concentration was 1 mg / L. In Examples 4 and 5, E. coli was not detected at 1 mg / L, and heterotrophic bacteria were not detected at 2 mg / L. On the other hand, in Comparative Examples 1 and 2, since a considerable amount of zooplankton remained in the filtered water, it was necessary to make the effective chlorine concentration 5 mg / L in order to reduce the number of plankton. In order to completely kill the plant, the effective chlorine concentrations had to be 2 mg / L and 5 mg / L, respectively. Thus, in Comparative Examples 1 and 2, hypochlorous acid was required 5 times or more that in Examples 1 to 3 and 2 times or more that in Examples 4 and 5. From the above, it can be said that the pore diameter of the depth filter is preferably 1 to 25 μm, and more preferably 1 to 10 μm.

Example 6 and Comparative Example 3
Natural seawater (water temperature 26 ° C.) was subjected to a continuous filtration test at a flow rate of 25 L / min using a depth filter (outer diameter 60 mm, inner diameter 30 mm, length 250 mm hollow cylinder) having a pore diameter of 3 μm. At that time, the case where the filtration was continuously performed (Comparative Example 3) and the case where the air was backwashed (air pressure 100 kPa, 5 seconds) every time the filtration was performed for 3 minutes were compared (Example 6). The results are shown in Table 3. When filtration was performed continuously, the filter closed and the differential pressure increased rapidly in 30 minutes, and almost no seawater flowed after that. However, when air backwashing was performed, the differential pressure was maintained after 600 minutes. Was stable.

  As described above, the preferred embodiments of the present invention have been described with reference to the drawings, but various additions, modifications, or deletions can be made without departing from the spirit of the present invention. For example, in each of the above embodiments, the chemical treatment units 3 and 3A are provided between the filtration unit 4 and the ballast tank 6, but the drainage side of the ballast tank 6, that is, the passage discharged from the ballast tank 6 to the outside. You may provide the chemical processing units 3 and 3A in the middle. In this case, the liquid containing hypochlorous acid does not flow into the ballast tank 6 and corrosion of the ballast tank 6 can be suppressed. Therefore, such a thing is also included in the scope of the present invention.

1 Ballast water production equipment (filtration system)
3,3A Chemical treatment unit 4 Filtration unit 6 Ballast tank 8 Water supply passage 8a Branch point 8b Junction point 9 Housing 10 Depth filter (filter material)
12 Fluid supply passage 14 Discharge passage 16 Filtrated water outlet 18 Raw water supply port 22 Discharge port 24 Fluid supply port 25 Throttle means 38 Filter medium 40 Fixing plate A Compressed air FW Filtered water RW Raw water

Claims (6)

A ballast water production apparatus including a filter medium and a housing that houses the filter medium, and comprising a filtration unit that filters raw water, and a chemical treatment unit that adds solid calcium hypochlorite to the filtrate filtered by the filtration unit. There,
The casing has a raw water supply port for supplying raw water to the filter medium, a filtered water outlet, a fluid supply port for supplying backwash fluid to the filter medium, a fluid obtained by backwashing the filter medium, and the raw water Has a discharge port for discharging
An apparatus for producing ballast water, wherein the filter medium is a depth filter having a pore diameter of 1 to 25 μm.   In claim 1, the chemical treatment unit is charged with the container containing solid calcium hypochlorite and the concentrated solution in which the solid calcium hypochlorite taken out from the container is dissolved, into the filtered water, An apparatus for producing ballast water, which is a unit for treating microorganisms with the generated hypochlorous acid. 3. The chemical treatment unit according to claim 1, wherein the chemical treatment unit dissolves the solid calcium hypochlorite in a part of the filtered water branched out from the water supply passage for supplying the filtrate, and the filtered water in the water supply passage. To join
The ballast water manufacturing apparatus provided with the throttle means which reduces the flow volume of the filtrate of the said water supply path between the said branch location and a merge location.   4. The ballast water production apparatus according to claim 1, 2, or 3, wherein the solid calcium hypochlorite is stored in a sealed container.   5. The filter medium according to claim 1, wherein the filter medium is disposed so as to be inclined obliquely upward toward the filtrate outlet, and the inclination angle is 20 to 70 ° with respect to a horizontal direction. Ballast water production equipment. A ballast water production method using the ballast water production apparatus according to any one of claims 1 to 5,
In a state where supply of filtered water from the filter medium to the ballast tank and supply of fluid to the filter medium are stopped, a preparation step of discharging the fluid together with raw water from the discharge port through the filtration unit;
In a state where the discharge of raw water from the filter medium and the fluid supply to the filter medium are stopped, the raw water is supplied to the filtration unit, and the filtered water is sent to the filtered water outlet,
While supply of filtered water to the ballast tank is stopped, while supplying raw water to the filter medium, a fluid is supplied from the filtered water side to the filter medium, and this fluid is supplied together with the raw water from the outlet to the discharge passage through the discharge passage. Backwashing process to discharge outside,
A ballast water production method comprising:

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