JP2010269200A - Water treatment apparatus and water treatment method - Google Patents

Abstract

The present invention provides a water treatment apparatus that performs high-speed water treatment in large quantities and increases the purification efficiency by reliably capturing fine solids, and is particularly suitable for ballast water treatment.
A magnetic particle supply unit that adds magnetic particles to raw water containing the object to be removed, and a magnetic filter, and the magnetic particle added by the magnetic particle supply unit adheres to the object to be removed. Separation device that is magnetically attached and separated when passing through the pores of the magnetic filter, and a porous filtration membrane having pores smaller than the pores of the magnetic filter, and was not removed by the magnetic separation device And a filtration device that captures an object to be removed in the raw water with the filtration membrane.
[Selection] Figure 2

Description

  The present invention relates to a water treatment apparatus and a water treatment method, and more particularly, to remove a removal object from raw water containing the removal object at high speed and surely, and in particular, a large amount is stored in a ship such as an oil tanker. It is preferably used for water treatment of ballast water.

In recent years, pollution of rivers and oceans from factory effluent and domestic effluent has increased.
When removing the solids contained in the contaminated water, the amount of water is large, so that the speed of the cleaning process is required. In addition, in water treatment that contains a large amount of microorganisms, plankton, and fungal bodies that cause contamination, it is necessary to capture the above-mentioned removal target with a filtration membrane having micron-scale pores, and in this case, it passes through the filtration membrane. It takes a long time, and trapped particles are likely to be clogged due to accumulation on the filtration membrane, so that high-speed and large-scale treatment of treated water is difficult due to the necessity of intermittent cleaning.

In recent years, the treatment of ballast water loaded on ships has become a problem. Ballast water is seawater that is loaded for safe navigation even in an empty state. Ballast water is taken from the nearby sea area when leaving the port, and drained to the ocean when loading the cargo when entering the port. That is, ballast water consisting of seawater from the port of departure is drained at the port of arrival. For example, when an oil tanker departing from Japan sails to the Middle East, such as Kuwait, an oil-producing country, It is loaded as ballast water and drained offshore in the waters of the Middle East.
When ballast water is discharged into a sea area different from the sea area where water is taken, organisms in the seawater are moved to sea areas that are not originally habitats, which greatly affects the marine ecosystem.

For this reason, some countries have already regulated the discharge of ballast water. In February 2004, an international convention for “regulation and management of ship ballast water and sediment” was issued by the International Maritime Organization. Adopted, construction ships after 2009 are required to install a ballast water treatment system that complies with the standards, and to purify ballast water in accordance with the contents of the Convention.
However, when a ballast water tank is a large tanker with a capacity of 1500 to 100,000 tons, and when the ballast water is exchanged to treated water on the sea during the voyage from departure to entry, it is necessary to perform mass treatment at a very high speed. is there. In addition, since seawater contains micron-unit microorganisms such as algae, it is difficult to perform mass processing at high speed as described above.

Conventionally, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 2000-254544 (Patent Document 1) a magnetic separation capable of separating and removing a material to be removed at a relatively high speed from raw water containing the material to be removed made of plant microorganisms such as algae. The device is provided.
In the magnetic separation device, iron oxide particles are added to raw water to impart magnetism to the object to be removed, and then passed through a magnetic filter, and the object to be removed is magnetically attached to the magnetic filter and separated and removed. . Since the object to be removed is separated and removed by magnetism as described above, the object to be removed can be separated and removed even if the water passage hole of the magnetic filter is widened, and the water treatment can be speeded up.

JP 2000-254544 A

As described above, the magnetic separation device of Patent Document 1 captures the object to be removed that has been magnetized by magnetism, so that the pores of the magnetic filter can be enlarged, and thus clogging is extremely caused by membrane filtration. It is difficult, and has the advantage that a large amount of water can be treated at high speed.
However, the apparatus using magnetic force cannot capture the removal object to which the magnetic particles are not attached to the object to be removed, and it is difficult to reliably increase the removal rate, and there is room for improvement in this respect. There is.

  On the other hand, as described above, the filtration device captures the object to be removed by the pores of the filtration membrane, so that the object to be removed that is larger than the pores can be reliably captured and separated and removed, thereby providing an advantage of high filtration performance. However, there is a problem in terms of high-speed processing because the removal object accumulates on the surface of the filtration membrane or between the membranes and clogging is likely to occur, the effective filtration membrane area is reduced and the permeate flow rate is liable to decrease.

In particular, in the treatment of ballast water, it is usually intended for large ships, and the treatment amount is extremely large as much as 10,000 tons per day. Is required to do. However, it is difficult to perform high-volume and high-performance filtration with existing equipment.
Thus, in the water treatment using only one of the magnetic separation device and the filtration device, it is not possible to obtain treated water from which a large amount of solid matter has been removed.

  The present invention has been made in view of the above problems, and can treat a large amount of raw water such as ballast water containing an object to be removed, and also improve the capture performance of the minute object to be removed. The issue is to provide.

In order to solve the above problems, the present invention provides:
A magnetic particle supply unit for adding magnetic particles to the raw water containing the object to be removed;
A magnetic separation device comprising a magnetic filter, wherein the magnetic particles added in the magnetic particle supply unit adhere and are magnetically separated to be removed when passing through the holes of the magnetic filter;
A filtration device comprising a porous filtration membrane having pores smaller than the pores of the magnetic filter, and capturing the object to be removed in raw water that has not been removed by the magnetic separation device;
The water treatment apparatus characterized by providing is provided.

The water treatment apparatus of the present invention first adds magnetic particles to raw water, attaches the magnetic particles to the object to be removed, imparts magnetism, and then removes the object to be removed from the raw water at high speed with a magnetic separation device. Separated and removed, the treated water treated by the magnetic separation device is microfiltered by a filtration device to reliably remove an object to be removed that could not be removed by the magnetic separation device.
In this way, first, since most of the objects to be removed, such as 90% or more, are removed by a magnetic separation device that can remove the objects to be removed at high speed, and then filtered by the filtration device, the objects to be removed in the raw water are small. As a result, clogging of the filtration membrane is less likely to occur, so that a decrease in the permeation flow rate of the filtration membrane can be suppressed, and the processing time can be shortened.
In this way, by taking advantage of each of the magnetic separation device and the filtration device and complementing each other's disadvantages, a large amount of raw water can be processed at a high speed and the removal rate of the object to be removed can be reliably increased.

  Specifically, it is preferable that the magnetic separation device is for removing the object to be removed having a size of 5 μm or more, and the filtering device is for removing the object to be removed having a size of 0.1 μm or more. And the amount of treated water per hour of the magnetic separation device is larger than the amount of treated water per hour of the filtering device.

The magnetic particles added to the raw water have an average particle size of 1 μm to 50 μm, preferably 1 μm to 20 μm. This can make the magnetic particles easy to adhere to an object to be removed such as microorganisms and make it difficult to release them after adhesion by setting the average particle diameter of the magnetic particles to 1 μm or more. On the other hand, when it exceeds 50 μm, there arises a problem that it adheres to the bottom of the ballast tanker or deposits on the bottom of the piping of the processing apparatus and does not work effectively.
It should be noted that an object to be removed larger than 50 μm can be removed at the time when the ballast water is taken into the tanker with a rough filter or the like, which has an advantage that the operation and maintenance of the apparatus on the ship are facilitated. Furthermore, this technique may be preferable from the viewpoint of returning plankton larger than 50 μm to the water area and maintaining the plankton necessary for fish.
The blending amount of the magnetic particles is preferably 0.2 to 5% by mass when the amount of raw water is 100. This is because when the blending amount of the magnetic particles is 0.2% by mass or more, it can be adhered to 90% or more of the object to be removed in the raw water, while it is excessively added by making it less than 5% by mass. Thus, magnetic particles floating in the raw water without being attached to the object to be removed can be suppressed.

As the magnetic particles to be added, simple substances or alloys of magnetic metals such as iron, nickel, cobalt, and silver, and oxides thereof are preferably used, and iron oxide particles are particularly preferably used.
When iron oxide particles having a hydroxyl group on the surface are used as the magnetic particles, if there are plant microorganisms such as algae in the raw water as in the case of the iron oxide particles, hydroxyl groups are also present on the surface of these plant microorganisms. Therefore, hydrogen bonds are formed and magnetism can be imparted to the microorganisms by the iron oxide particles.

The magnetic particle supply unit includes a magnetic particle inlet of any one of the following (1), (2), and (3), and further includes a stirring unit that mixes the magnetic particles added to the raw water into the raw water. It is preferable.
(1) A magnetic particle inlet provided in a raw water tank connected to the magnetic separator through a raw water supply pipe;
(2) Magnetic particle inlet provided in the middle of the raw water supply pipe from the raw water tank to the magnetic separation device;
(3) Magnetic particle inlet provided in the raw water temporary storage tank connected to the raw water tank via a raw water supply pipe and connected to the magnetic separator via a pipe:
(2) A magnetic particle inlet is provided in the middle of the raw water feed pipe, and when magnetic particles are put into the raw water flowing through the feed pipe from the inlet, the magnetic particles are dispersed by the raw water flow and mixed with the raw water. In addition, if a stirrer that rotates according to the flow rate of the raw water is provided in the feed pipe, a drive source for stirring can be dispensed with.
Moreover, when the raw water storage tank provided with the apparatus which throws in and stirs the magnetic particle of said (3) is provided, as a water treatment apparatus provided with a series of apparatuses including this raw water storage tank, a magnetic separation apparatus, and a filtration apparatus It can be provided, and it is only necessary to connect the raw water supply pipe to the existing equipment.
Furthermore, when supplying magnetic particles directly to the raw water tank of (1), the raw water supply port to the tank can be used as an inlet for magnetic particles.

Preferably, the magnetic separation device includes an electromagnet for magnetizing the magnetic filter, and the electromagnet includes a coil of a superconducting wire and is a superconducting magnet.
The superconducting wire is preferably a high-temperature superconducting coil using a high-temperature superconducting wire (Bi-2223-based silver sheath wire, Re-based thin film wire).
The magnetic separation magnet system using this high-temperature superconducting coil may be a refrigerator-cooled system that does not use a refrigerant (refrigerant-free), or a liquid nitrogen cooling or liquid nitrogen supercooling system that uses liquid nitrogen.

As described above, when magnetic separation is performed using a superconducting magnet, a strong magnetic field can be formed around a fine wire of a magnetic filter made of a magnetic material such as stainless steel disposed in a strong magnetic field generated by the superconducting magnet. By using this strong magnetic field, the removal object to which the magnetic particles dispersed in the raw water adhere and are magnetized can be separated by being magnetized around the fine line.
In addition, when an oxide superconducting wire is used as a superconducting wire, the critical temperature is higher than that of a metal superconducting wire. Is stable.
Further, since liquid nitrogen can be used as the refrigerant, particularly when used as a ballast water treatment apparatus, even if it is mounted on a ship and used, it is extremely stable against fluctuations of the ship. In addition, an electromagnet using an oxide superconducting wire can be configured to be lighter and more compact than an electromagnet using a metal-based superconducting wire, and is installed in a place where the installation area or weight of a ship or the like is greatly restricted. Is advantageous in some cases.
Furthermore, the magnetic filter to which the magnetic field is applied by the electromagnet of the oxide superconducting wire coil can be demagnetized at a high speed when demagnetized during cleaning to remove the attached object to be removed, and can be excited at a high speed. As described above, since the magnetic field can be generated and erased in the magnetic separation device in a short time, the time required for cleaning the magnetic filter can be shortened, and the separation processing efficiency can be increased.

In addition, the magnetic filter forms holes by knitting fine wires made of a magnetic material mainly composed of stainless steel, iron, nickel, cobalt, etc. into a mesh shape, and the average area of the holes is 0.5 mm ^2. It is preferable to be set to ˜100 mm ² .
When the magnetic filter is formed of a stainless steel wire, rust is less likely to occur and a durable magnetic filter can be obtained.
Further, a magnetic filter formed by the mesh of the wire of stainless steel wire or the like, the average area of the holes formed by the mesh and 1 mm ² 25 mm ^2, especially-be-removed substance more magnetic 5μm was granted 90 % Or more can be separated.

  The magnetic separation device includes a large-diameter processing tube through which raw water added with magnetic particles flows inside a case, and the magnetic filters are arranged in parallel along the flow path in the processing tube. An annular electromagnet including a coil around which the superconducting wire is wound is fitted on the outer periphery of a processing tube in which these magnetic filters are arranged in parallel, and the magnetic filter is disposed in the magnetic field of the superconducting magnet.

  In addition, a magnetic filter cleaning device is disposed in the case of the magnetic separation device to spray the compressed fluid and blow off the object to be removed attached to the magnetic filter, and the magnetic filter is disposed in parallel with the magnetic filter cleaning device in the processing tube. Is provided at a predetermined time interval, and a circulation transfer means for returning to a position along the raw water flow path after cleaning is provided. The compressed fluid may be compressed air or a compressed liquid.

Specifically, the magnetic filters arranged in parallel in the processing tube can be moved from the outflow side to the inflow side at the same time while maintaining a constant pitch, and intermittently from the outflow side to the inflow side with a predetermined time interval. The magnetic filter is moved to the magnetic filter cleaning device by the circulating transfer means from the magnetic filter to which the object to be removed is most likely to adhere at the inflow end.
At the time of the cleaning, the magnetic filter is demagnetized because it is out of the magnetic field range of the electromagnet, so that the magnetically removed object is easily detached and can be reliably removed from the magnetic filter by spraying a compressed fluid. In addition, the removed object to be removed is stored in a storage serving as a receiving material so that it is not scattered outside the case.

  The filtration device preferably includes a PTFE (polytetrafluoroethylene) porous membrane as the filtration membrane, and the PTFE (polytetrafluoroethylene) porous membrane preferably has a maximum pore size of 0.1 μm to 10 μm. The average pore diameter can be measured by a palm porometer model number CFP-1200A manufactured by PMI.

The PTFE is extremely excellent in durability such as mechanical strength and chemical resistance (acid resistance, alkali resistance, oxide resistance) and the like, and can be used for a wide range of water to be treated and has excellent durability. can do. PTFE has strength even as a thin porous membrane having a maximum pore diameter of 0.1 μm to 10 μm and a thickness of about 5 μm to 500 μm.
The reason why the maximum pore size is 0.1 μm to 10 μm is that the size of the particles contained in various wastewaters is different, and the removal object to be contained is ensured by selecting the pore size of the filtration membrane according to its properties and purpose. To capture. For example, when bacteria having a minimum size of 0.2 microns float in the water to be treated, a maximum pore size of 0.1 microns may be selected.

The filtration device is preferably formed from a hollow fiber membrane module in which hollow fibers having a porous membrane made of PTFE (polytetrafluoroethylene) are converged. The hollow fiber having the PTFE porous membrane may be a single layer made of only the PTFE porous membrane or may be a laminate of a plurality of layers. On the other hand, a sheet-like PTFE porous membrane may be used, but in that case, a sheet-like, tubular, or bag-like unit can be modularized in combination with a non-woven fabric or a net that supports other channels. It may be used.
A plurality of the hollow fiber membranes or sheet-like membranes are converged to produce a membrane module element, which can be used in several forms.
Specifically (1) A plurality of the membrane module elements are immersed in a dipping tank filled with the water to be treated, and sucked with a pump through the porous membrane to obtain treated water;
(2) A method in which the membrane module element is sealed and placed in a pressurized container and filtered with a pressure pump to obtain treated water:
A diffuser tube is arranged in the immersion tank and the pressurized container, and the bubbling between the membrane modules or between the dense membranes of each membrane module is performed to suppress the adhesion of the object to be removed that adheres to the surface of the filtration membrane. preferable.

  The filtration membrane has a maximum pore diameter of 0.1 to 10 μm. For example, in one hollow fiber membrane module, 500 to 5000 fibers are converged. The diameter and number of the hollow fiber membranes depend on the amount of treated water, etc. Varies and not limited.

In the filtration device, backwashing is performed to prevent clogging of the membrane surface.
Specifically, the treated water generated by the filtering device is used to periodically remove the adhering substance that is deposited on the film surface and causes a decrease in the flow rate by creating a reverse flow by pressurization in the reverse direction to the filtration. At that time, concentrated drainage containing many fine particles not filtered is generated on the membrane module side. About this, since contained fine particles aggregate and a particle size becomes large, it can return to the raw | natural water side of the said magnetic separation again, and this can be filtered by the previous magnetic separation.
As another treatment method for this backwash wastewater concentrate, an electrolysis apparatus is also provided, and the remaining concentrate is sent to the electrolysis apparatus through a pipe, in which various oxidation active species, hydroxyl radicals and Chlorite ions are generated or nanobubbles are applied to sterilize and detoxify remaining bacteria of less than 0.1 μm.

Further, not only the sterilization treatment of the backwash concentrated waste water of the filtration device but also an electrolysis device having the sterilization function is provided in connection with the magnetic separation device and / or the treated water extraction pipe of the filtration device, The treated treated water or the treated water treated by the filtration device may be electrolyzed to generate an oxidatively active species according to the purpose, and sterilized by this. Thereby, microorganisms such as bacteria and viruses having a size of 0.1 microns or less that could not be removed by the filtration device can be killed, or dissolved organic substances can be decomposed or deodorized.
On the other hand, it is desirable to supply a liquid containing oxidation active species generated by electrolysis of the treated water of the filtration device as washing water for the membrane module of the filtration device. This eliminates the need for commonly used membrane cleaning chemicals such as sodium hypochlorite.

That is, the following configurations (1) to (3) are preferable.
(1) The filtration device is connected to an electrolysis device through a pipe, and treated water containing residual components that are not filtered is supplied to the electrolysis device to be discharged, stored, or reused after the electrolysis treatment.
(2) The filtration device is connected to the electrolysis device through a pipe, and backwash water from the filtration device is supplied to the electrolysis device for electrolysis, sterilized and discharged out of the system.
(3) The filtration device is connected to an electrolysis device through a pipe, and the filtered treated water is supplied to the electrolysis device for electrolysis treatment, and the electrolytic solution electrolyzed by the electrolysis device is filtered by the filtration device. Supply as membrane cleaning water.

In the water treatment device of the present invention, a temporary storage tank is provided between the magnetic separation device and the filtration device, and a pump is provided in a pipe from the temporary storage tank to the filtration device, so that the treated water to the filtration device is provided. It is preferable to control the supply amount.
That is, since the amount of treated water per hour by the magnetic separation device is larger than the amount of treated water per hour by the filtration device, the treated water treated by the magnetic separation device is stored in the temporary storage tank, and the magnetic separation device and the filtration device are stored. We are trying to adjust the processing time.

It is preferable that the amount of treated water in the magnetic separation device is set to 200 t / hour or more per 1 m ³ of the installed volume, and the amount of treated water in the filtration device is set to 100 t / hour to 200 t or less / hour of the installed volume of 1 m ^3. .
If it is said setting, it will become possible to process raw water of 1500 tons to 100,000 tons in about a half day to a week.

Therefore, the above-described water treatment device of the present invention is mounted on a ship and is suitably used as a ballast water treatment device in which the raw water stored in the raw water storage tank is ballast water.
That is, when a large amount of ballast water can be removed with a magnetic separator at high speed, the treated water from which 90% or more of the removed matter has been removed by the magnetic separator is filtered through a filtration membrane with a filtration device. Since the object to be removed hardly adheres to the filtration membrane, even if the pores of the filtration membrane are small, the reduction of the permeate flow rate can be suppressed, and the filtration process can be speeded up. In addition, a fine object to be removed that could not be separated by the magnetic separation device can be removed by the filtration device, and a large amount of ballast water can be removed at a high speed and the removal rate of the object to be removed is 95% or more.

Furthermore, as a second invention,
Adding and mixing magnetic particles in raw water, and attaching the magnetic particles to the object to be removed contained in the raw water to impart magnetism; and
A magnetic separation step of magnetizing the object to be removed with magnetism applied to a magnetic filter and separating and removing the object to be removed from the raw water;
The treated water treated in the magnetic separation step is filtered through a filtration membrane having a smaller area for pores for capturing particles than the magnetic filter, and a filtration step for separating and removing remaining objects to be removed;
A water treatment method is provided.
This water treatment method of the present invention can be most efficiently performed by the above-described water treatment apparatus of the present invention.

In the water treatment method of the present invention described above,
90% by mass or more of the object to be removed in the raw water is removed in the magnetic separation step, and the object to be removed in the treated water and the magnetic material are separated and removed in the magnetic separation step in the filtration step by the filtration membrane. Remove the particles,
98 mass% or more of the to-be-removed thing in the said raw water can be removed by the magnetic separation process of a front | former stage, and the filtration process of a back | latter stage.

The water treatment method of the present invention is most preferably used as a treatment for ballast water stored in a ballast tank of a ship.
That is, the magnetic particles are attached to the removal object composed of plant microorganisms and animal microorganisms including algae floating and precipitated in the ballast water to give magnetism, and separated and removed in the magnetic separation step, and the magnetic separation step The to-be-removed object that has not been removed in step 1 is removed by the filtration step, or when necessary, bacteria in the ballast water are sterilized by electrolytic treatment.

The treated water of the ballast water after the treatment by the filtration device has less than 10 live individuals per 1 m ³ of organisms having a minimum size of 50 μm or more, and less than 10 live individuals per ml of organisms having a minimum size of 10 μm or more and less than 50 μm. It can be.

When the ballast water treatment is performed on the ocean where the ship is sailing, the navigation date is not less than half a day, and when the total amount of ballast water is not more than 100,000 tons, most of the ballast water is not less than 95% when draining the ballast water. Can be processed.
When ballast water is treated as the setting, most large vessels can meet the outline adopted by the international convention for “regulation and management of ballast water and sediment of the vessel”.

  As described above, in the water treatment device of the present invention, solids can be separated and removed at high speed from a large amount of raw water such as ballast water by the magnetic separation device, and fine solids and bacteria that could not be removed by the magnetic separation device. Can be reliably removed. Therefore, it can be suitably used as a ballast water purification device that needs to process a large amount of water at high speed.

Embodiments of the present invention will be described with reference to the drawings.
The water treatment apparatus 10 of 1st embodiment is shown in FIG. 1 thru | or FIG.
The water treatment apparatus 10 is mounted on a large vessel 100 such as an oil tanker, and performs removal processing of an object to be removed made of solid matter such as marine organisms contained in the loaded ballast water 11 on the sea during navigation.

  As shown in FIG. 1, the large vessel 100 includes a plurality of ballast water tanks 11 on the bottom side, and the total amount of ballast water is, for example, about 1500 to 100,000 tons. When ballast water is processed during voyage, the ballast water stored in the plurality of ballast water tanks 11 is sequentially supplied to the ballast water treatment device 10 and is exchanged with the treated water. It is stored again in the tank 11, all the ballast water is processed and returned to the ballast water tank 11 for storage.

  As shown in FIG. 2, the water treatment apparatus 10 includes a raw water storage tank 13 that adds and mixes magnetic particles to ballast water supplied from a ballast water tank 11 via a pipe 104, and a raw water storage tank 13. The two magnetic separation devices 14 for processing the supplied ballast water Q1, the temporary storage tank 15 for temporarily storing the treated water processed by the magnetic separation device 14, and the temporary storage tank 15 are supplied. Two filtration devices 16 for reprocessing treated water and an electrolysis device 17 connected to the filtration device 16 are provided.

A pump 18 is provided in a pipe P1 between the raw water storage tank 13 and the magnetic separation device 14, the pipe P1 is branched into two on the discharge side of the pump 18, and the branch pipe is divided into two magnetic separation devices 14A. , 14B, and ballast water is supplied to the magnetic separators 14A, 14B at a required water pressure. The two magnetic separation devices 14A and 14B are connected to the temporary storage tank 15 via the pipe P2, and temporarily store the treated water that has been magnetically separated.
A pump 19 is provided in a pipe P3 between the temporary storage tank 15 and the filtering device 16, and the pump 19 branches into two on the discharge side of the pump 19. The branch pipe is connected to the two filtering devices 16A and 16B. The treated water filtered by the filtration devices 16A and 16B is supplied to the pipe P4, and the pipe P4 is connected to the empty ballast water tank 11 via the pipe 101 shown in FIG. Pumps 102 and 103 are interposed in the pipe 101 and the pipe 104 for supplying the ballast water to the water treatment device 10, respectively.
Moreover, it connects with the electrolysis apparatus 17 via the piping P5 which takes out the concentrate which remained without being filtered from each filtration tank of the said 2 filtration apparatuses 16. FIG. A part of the treated water electrolyzed by the electrolyzer 17 is connected to the ballast water tank 11 by the pipe P6, and a part of the treated water is returned to the filter apparatus 16 by the pipe P7 and used as backwash water for the filtration membrane. Yes.

  The raw water storage tank 13 is provided with an inlet 13a for adding powdered magnetic particles 12 to the stored ballast water Q1. As the magnetic particles 12, iron oxide particles having a hydroxyl group on the surface are used. A stirring means (not shown) for stirring and mixing the ballast water Q1 and the magnetic particles 12 is attached to the inside of the raw water storage tank 13, and the magnetic particles 12 are attached to the object to be removed contained in the ballast water so as to be magnetized. The magnetic bearing ballast water Q2 is provided.

  The magnetic particles 12 added to the raw water storage tank 13 have an average particle diameter of 1 μm to 50 μm, and the amount of ballast water is 100% by mass, the magnetic particles 12 are added at 0.2 to 5% by mass.

As shown in FIG. 3, the magnetic separation device 14 is divided into two magnetic separation devices 14 </ b> A and 14 </ b> B by separating the inside of the case 40 by a partition wall 24.
A large-diameter processing tube 20 is installed horizontally in each of the magnetic separation devices 14A and 14B, and a supply port 20a at one end of the processing tube 20 is connected to a pipe P1 for supplying the magnetic ballast water Q2. The outlet 20b is connected to the pipe P2. The processing tube 20 is made of a non-magnetic stainless steel or a magnetically permeable material made of FRP or plastic.
A large number (24 in this embodiment) of magnetic filters 21 each having a disk shape are arranged in parallel in the direction orthogonal to the axial direction inside the processing tube 20. In addition, a large number of magnetic filters 21 are arranged in the processing tube 20 so as to be movable toward the supply port 20a while maintaining a constant pitch from the outlet 20b.
Further, the processing tube 20 is provided with a magnetic filter outlet 20c on the outer periphery in the vicinity of the supply port 20a, and a magnetic filter inlet 20d is provided on the outer periphery in the vicinity of the outlet 20b so that it can enter and exit in the radial direction. .

Each of the magnetic filters 21 is made of a metal wire mesh made of a magnetic material. In this embodiment, the hole 21a is formed of a stainless steel mesh and has a diameter of 30 mm and is surrounded by a mesh. The length of one side of the hole 21a is about 5 mm, and the hole is 25 mm ^2. I can do it. Further, about 20 magnetic filters 21 made of stainless steel are arranged in parallel in the processing tube 20 at a constant pitch.

A superconducting magnet 22 is fitted and fixed to the outer peripheral surface of the processing tube 20. The superconducting magnet 22 is formed of a coil 22a around which an oxide superconducting wire is wound, and is accommodated in a cooling vessel 22b that maintains the coil 22a at a superconducting temperature.
In this embodiment, it is composed of a coil in which double pancakes of bismuth 2223 series oxide superconductor wire are laminated.
All the magnetic filters 21 in the processing tube 20 are set in a magnetic field generated by the superconducting magnet 22, so that all the magnetic filters 21 generate a strong magnetic field by the superconducting magnet.
The coil has, for example, a room temperature bore diameter of 30 mm, a magnet size inner diameter of 50 mm, an outer diameter of 150 mm, and a height of 200 mm. With liquid nitrogen supercooling (68K), 0.5T (at 200A energization), with refrigerator cooling (20K) 4T (200A energized).

Since the solid matter to be removed adheres to the magnetic filter 21 and needs to be cleaned periodically, a magnetic filter washer 25 for blowing compressed air is installed in each of the magnetic separation devices 14A and 14B. The filter washer 25, the magnetic filter outlet 20c of the processing tube 20 and the magnetic filter inlet 20d are connected by circulation conveying pipes 26A and 26B.
The magnetic filter 21 before cleaning is transported from the magnetic filter outlet 20c to the magnetic filter cleaner 25 through the circulation transport path 26A, and the magnetic filter 21 after cleaning is transported to the filter inlet 20d through the circulation transport path 26B. In this conveyance, the magnetic filter 21 is conveyed by air pressure or a motor.
In the magnetic filter washer 25, as shown in FIG. 4, a nozzle 27 for blowing compressed air is provided on one side of the magnetic filter 21 that is positioned and held, and a storage 28 for receiving the removed solid matter is provided on the other side. ing.

As shown in FIG. 5, the filtration device 16 (16 </ b> A, 16 </ b> B) has a configuration in which a plurality of hollow fiber membrane modules 30 are suspended vertically in each immersion tank 35 and immersed in the liquid.
Each of the hollow fiber membrane modules 30 converges a number of hollow fibers 31 made of a PTFE (polytetrafluoroethylene) porous membrane, and the hollow fibers 31 are integrally focused and fixed by fixing members 32 (32b, 32a) at both upper and lower ends. Consisting of

  In this embodiment, a hollow fiber having a maximum pore diameter of 0.1 to 10 μm is used as each hollow fiber 31, and 80 to 350 fibers are converged to form one hollow fiber membrane module 30. This makes it possible to capture solids of less than 50 μm that could not be removed by the magnetic separation device 14. In addition, the hollow fiber 31 can capture solids and bacteria of 0.1 μm or more.

  Specifically, the hollow fiber membrane module 30 focuses a large number of hollow fibers 31 that are open at both ends, the lower end opening of the hollow fiber 31 is molded with resin and sealed with the lower fixing member 32a, and the upper end opening is The water collecting header 33 is communicated with the water collecting pipe 34 while being communicated with the inside of the water collecting header 33 while being held by the upper fixing member 32 b. The water collection pipe 34 of each hollow fiber module 30 is connected to the pipe P4 that is a single common treatment liquid collection pipe so that the filtered treated water that has passed through the filtration membrane can be fed together.

  A feed port 35g is provided in the bottom wall 35a of the filtration tank 35, the feed port 35g is communicated with the temporary storage tank 15 via a pipe P3, and the magnetic force is supplied from the pump 19 provided in the pipe P3 at a required pressure. The treated water Q3 from which the solid matter has been separated and removed by the separation device 14 is caused to flow into the filtration tank 35 to form an immersion suction filtration type. That is, the treated water Q3 supplied to the filtration tank 35 flows through the hollow fiber 31 from the outer peripheral surface to the inner peripheral surface and is filtered, and the filtered treated water Q4 flows into the hollow portion, and the treated water Q4 in the hollow portion is supplied. Suction is performed by a pump 105 interposed in the pipe P4.

  Furthermore, in order to continue the stable filtration process in the filtration device 16, a water pipe 33 is provided below the hollow fiber module 30, and pressurized air is supplied to the pipe 33 from the air blower 37. Yes. Pressurized air supplied to the pipe 33 is injected from a gas injection hole 33a provided in the pipe 33, and bubbling is generated in the treatment liquid Q3, so that solid matter deposited on the surface of the hollow fiber 31 or between the membranes can be peeled and removed. I am doing so.

The filtration devices 16A and 16B are connected to the electrolysis device 17 via a pipe P5 for taking out the concentrated solution remaining without being filtered in each filtration tank 35. The concentrate remaining in the filtration tank is about 1 to 5% of raw water to be treated in the magnetic separation step and the filtration step.
The electrolyzer 17 has a structure in which a platinum electrode serving as a cathode and an anode is suspended in an electrolytic cell and immersed in the treatment liquid Q3 for electrolysis.
Since chloride ion (Cl-) contained in seawater is dissolved in the treated water Q3, chlorine ions are converted into chlorine (Cl2) by the anode plate by the electrode reaction, and hydroxide ions are obtained by the cathode plate. (OH-) is produced, and hypochlorite ions (ClO-) are produced by the reaction of chlorine (Cl2) and hydroxide ions (OH-).
Hypochlorite ions (ClO-) generated in this way can kill bacteria defined in the international treaty to a concentration below the standard value.

  A part of the treated water Q5 electrolyzed by the electrolyzer 17 is connected to the ballast water tank 11 via the pipe P6 as described above, and the remainder of the treated water Q is periodically passed through the pipe P7 to the filtration tank 35. It is supplied into the hollow fiber 31 and used as backwash water.

In the water treatment device 10, the amount of treated water in the magnetic separation device 14 is set to 200 t / hour or more per 1 m ³ of the installation volume. Further, the amount of treated water in the filtration device 16 is set to 100 t / hour to 200 t / hour / hour per 1 m ³ of the installation volume. The amount of treated water in the entire water treatment apparatus 10 is set to 100 t / hour per 1 m ³ of the installation volume.

Next, the ballast water treatment process performed by the water treatment apparatus 10 will be described.
First, the ballast water Q1 stored in the ballast water tank 11 (11A) storing the ballast water Q1 is supplied to the raw water storage tank 13 of the water treatment apparatus 10 and stored.
Next, the magnetic particles 12 are added to and mixed with the ballast water Q1 stored in the raw water storage tank 13, and the magnetic particles 12 are attached to the solid matter in the ballast water Q1 to impart magnetism (magnetization step). ).

  In the raw water storage tank 13, magnetic particles can be attached to 90% or more of the solids floating and precipitated in the ballast water Q <b> 1 by the hydrogen bond, and magnetism can be imparted to the solids, and the ballast water in the raw water storage tank 13 can be The magnetic bearing ballast water Q2. Of the added magnetic particles 12, the magnetic particles 12 that do not adhere to the solid matter are dispersed and floated in the ballast water.

Next, the magnetic bearing ballast water Q2 containing the solid matter to which the magnetism is imparted is supplied to the magnetic separation device 14 and circulated through the processing tube 20 in the magnetic separation device 14.
Since a large number of magnetic filters 21 are arranged in the processing tube 20 from the upstream side to the downstream side, the stainless wire surrounding the air holes of the magnetic filters 21 generates strong magnetism by the superconducting magnet 22. When the magnetic ballast water Q2 passes through the magnetic filter 21, it is magnetically attached to the stainless steel wire, and solids are separated and removed from the magnetic ballast water Q2 (magnetic separation step).

In the magnetic separation step, the solid material consisting of the object to be removed of 5 μm or more in the ballast water Q1 is strongly magnetized because many magnetic particles 12 adhere thereto, and the solid material of 5 μm or more can be almost separated, and the solid material in the ballast water Q1 can be separated. About 90% or more of objects can be separated and removed.
On the other hand, magnetic particles are difficult to adhere to solids of less than 5 μm, and even if attached, the number of magnetic particles is small, so that they are weakly magnetized. Therefore, solids less than 5 μm may not be separated and removed in the magnetic separation process, and ultrafine solids less than 5 μm are likely to remain in the treated water Q3 obtained in the magnetic separation process. In addition, magnetic particles that float without solid matter remaining may remain.

Since the amount of treated water per hour of the magnetic separator 14 is larger than the amount of treated water per hour of the filtration device 16 disposed in the subsequent stage, the treated water Q3 treated by the magnetic separator 14 is temporarily stored temporarily. Once stored in the tank 15. The treated water Q3 stored in the temporary storage tank 15 is pressurized and supplied to the filtration device 16 while adjusting the discharge amount by the pump 19.
However, since it is desirable for the entire apparatus to ideally match the processing capabilities of the magnetic separation device 14 and the filtration device 16, it is preferable to increase the number of filtration devices as necessary.

The treated water Q3 pressurized and supplied into the filtration device 16 is made into a filtration membrane of the hollow fiber 30 of the hollow fiber module 31, and is reduced to less than 5 μm remaining in the treated water Q3 by the porous membrane of the hollow fiber 30 by external pressure filtration. .Capturing and removing solids of 1 μm or more. (Filtering process)
Since the filtration device 16 is set to capture particles of 0.1 μm or more, solids and bacteria of 0.1 μm or more contained in the ballast water Q1 can be removed.
In addition, since almost 90% of the solids in the treated water is separated and removed from the treated water Q3 filtered by the filtration device in the preceding magnetic separation step, the solids adhering to both surfaces of the hollow fiber 31 are very little, Therefore, even if the pores through which the treatment liquid permeates are small, the treatment flow rate is not lowered and the filtration can be performed at a relatively high speed.
Further, the concentrated solution remaining without being removed even in the filtration step is fed to the electrolysis device 17 and subjected to electrolytic treatment, so that bacteria of less than 0.1 μm contained in the concentrated solution can be sterilized.

Thus, in the water treatment apparatus 10, marine organisms of 0.1 μm or more contained in the ballast water can be separated and removed by the magnetic separation step and the filtration step, and more than 95% of the solid matter contained in the ballast can be reliably obtained. Can be separated.
Specifically, 90% by mass or more of the solid matter in the ballast water Q1 is removed in the magnetic separation step, and the solid matter and magnetic particles in the treated water from which the solid matter is separated and removed in the magnetic separation step are captured in the filtration step. And 98 mass% or more of the solid substance in the ballast water Q1 is removed.
As a result, in the treated water obtained through the filtration step, the number of living individuals per 1 m ³ of organisms having a minimum size of 50 μm or more is less than 10, and the number of living individuals per ml of organisms having a minimum size of 10 μm or more and less than 50 μm is 10. Less than.

Further, in the water treatment device 10, the magnetic separation device 14 and the filtration device 16 that capture and separate solid matter are periodically washed to reduce the permeate flow rate and to improve the processing efficiency.
That is, in the magnetic separation device 14, solid matter adheres around the stainless steel wire of the magnetic filter 21, and the pore area surrounded by the stainless steel wire is reduced to reduce the processing flow rate. The magnetic filter 21 is taken out in order from the magnetic filter outlet 20c on the supply port side, which is large, and is conveyed to the magnetic filter cleaner 25.
During this conveyance, the magnetic filter 21 is demagnetized because it deviates from the magnetic field of the superconducting magnet 22. Therefore, it is not necessary to demagnetize the superconducting magnet 22 itself, and the magnetic separator is continuously operated.
When one magnetic filter 21 is taken out from the processing tube 20, the regenerated magnetic filter 21 is inserted into the processing tube 20 from the magnetic filter inlet 22d at the downstream end, so that the required number of magnetic filters 21 are always in the processing tube. The magnetic separation performance is not deteriorated by allowing a large number of magnetic filters 21 to pass therethrough.
Moreover, in the magnetic filter washer 25, since the solid matter blown off from the magnetic filter 21 by compressed air is stored in the storage 28, the solid matter branched off from the ballast water is not scattered outside the apparatus.

The washing of the hollow fiber 31 in the filtration device 16 is performed by periodically supplying a part of the treated water Q5 electrolyzed by the electrolyzer 17 into the hollow fiber 31 through the pipe P7 and reversing the treated water Q5 made of the electrolyzed water. The washing water is sprayed from the inner peripheral side of the hollow fiber 31.
In this way, by spraying the electrolyzed water by back pressure cleaning, the adhering foreign matter present on the outer peripheral surface of the hollow fiber 31 can be decomposed and removed and sterilized. Further, the concentrated raw water (processed water Q3) that remains in the filter tank 35 before the filtration process can be periodically supplied to the electrolyzer 17 to be electrolyzed to be sterilized and detoxified.

  As described above, the water treatment apparatus of the present invention can separate and remove solids from a large amount of ballast water at high speed with a magnetic separator, and can reliably remove fine solids that could not be removed with the magnetic separator. Therefore, it can be suitably used as a ballast water purification device.

FIG. 6 shows a second embodiment.
In the second embodiment, the inlet 120 is provided in the middle of the supply pipe 104 supplied from the ballast water tank 11 to the water stop treatment apparatus 10, and the downstream end of the supply pipe 104 is directly connected to the magnetic separation device 13. The raw water storage tank into which the magnetic particles of the first embodiment are charged is unnecessary.
When the magnetic particles 12 are charged from the charging port 120, the lid 121 attached to the charging port 120 is opened, and a predetermined amount of the magnetic particles 12 is charged into the ballast water Q1 flowing through the supply pipe 104. In addition, an impeller 122 formed of a nonmagnetic material is fitted in the supply pipe 104 downstream from the inlet 120, and the magnetic particles 12 are stirred by the flow rate of the ballast water Q1 to which the magnetic particles 12 are added. Evenly mixed inside.
If it is set as this 2nd embodiment, a raw | natural water storage tank can be eliminated and size reduction of a water stop processing apparatus can be achieved.

FIG. 7 shows a third embodiment.
In the third embodiment, the raw water inlet 11a of the ballast water tank 11 is used as the inlet for the magnetic particles 12, and the magnetic particles 12 are directly supplied into the tank for storing the raw water to be processed. The ballast tank 11 charged with the magnetic particles 12 is connected to a pipe, and the pipe is connected to the magnetic separation device 13 as in the second embodiment, so that the raw water storage tank of the first embodiment is unnecessary.
Furthermore, after putting the magnetic particles 12 into the ballast water tank 11, a stirrer (not shown) is inserted into the ballast water tank 11 through the raw water inlet 11a, and the ballast water Q1 into which the magnetic particles 12 have been put is stirred. ing.

The present invention is not limited to the above-described embodiment, and can be suitably used for a large amount of water treatment other than mounting on a ship and treating ballast water.
Further, an electrolytic device for sterilizing bacteria in the raw water may be provided connected to the treated water extraction pipe of the magnetic separation device, and the treated water after the magnetic separation step may be subjected to electrolytic treatment and then supplied to the filtration device.

  The water treatment apparatus and the water treatment method of the present invention not only treats ballast water, but also treats solids such as papermaking wastewater, factory wastewater (semiconductor, steel, food treatment, etc.), hospital wastewater treatment, etc. It can be widely used as a purification device for industrial wastewater containing many. Furthermore, it is also effective as a pretreatment device for a desalination process of a seawater desalination apparatus.

It is the schematic which shows embodiment which mounts the water treatment apparatus of this invention in the ship. It is drawing which shows the structure of the said water treatment apparatus. It is a block diagram which shows the magnetic separation apparatus of the said water treatment apparatus. It is a principal part enlarged view of FIG. It is the schematic which shows a filtration apparatus. It is drawing which shows 2nd embodiment. It is drawing which shows 3rd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Water treatment apparatus 11 Ballast water tank 12 Magnetic particle 13 Raw water storage tank 14 (14A, 14B) Magnetic separation apparatus 15 Temporary storage tank 16 (16A, 16B) Filtration apparatus 17 Electrolysis apparatus 18, 19, 102, 103 Pump 20 Processing pipe 21 Magnetic Filter 22 Superconducting Magnet 25 Magnetic Filter Washer 30 Hollow Fiber Membrane Module 31 Hollow Fiber 100 Ship Q1 Ballast Water Q2-Q5 Treated Water

Claims (16)

A magnetic particle supply unit for adding magnetic particles to the raw water containing the object to be removed;
A magnetic separation device comprising a magnetic filter, wherein the magnetic particles added in the magnetic particle supply unit adhere and are magnetically separated to be removed when passing through the holes of the magnetic filter;
A filtration device comprising a porous filtration membrane having pores smaller than the pores of the magnetic filter, and capturing the object to be removed in raw water that has not been removed by the magnetic separation device;
A water treatment apparatus comprising:   The magnetic separation device is for removing the object to be removed of 5 μm or more, the filtration device is for removing the object to be removed of 0.1 μm or more, and the amount of treated water per hour of the magnetic separation device is the filtration The water treatment apparatus according to claim 1, wherein the water treatment apparatus is larger than the amount of treated water per hour of the apparatus. The magnetic particle supply unit includes a magnetic particle inlet of any one of the following (1), (2), and (3), and further includes a stirring unit that mixes the magnetic particles added to the raw water into the raw water. The water treatment apparatus according to claim 1 or claim 2.
(1) A magnetic particle inlet provided in a raw water tank connected to the magnetic separator through a raw water supply pipe;
(2) Magnetic particle inlet provided in the middle of the raw water supply pipe from the raw water tank to the magnetic separation device;
(3) Magnetic particle inlet provided in the raw water temporary storage tank connected to the raw water tank via a raw water supply pipe and connected to the magnetic separator via a pipe:   The water treatment apparatus according to any one of claims 1 to 3, wherein the magnetic separation device includes an electromagnet that magnetizes the magnetic filter, and the electromagnet includes a coil of a superconducting wire.   The filtration device includes a PTFE (polytetrafluoroethylene) porous membrane as the filtration membrane, and the PTFE (polytetrafluoroethylene) porous membrane has a maximum pore size of 0.1 µm to 10 µm. The water treatment apparatus according to any one of 4.   6. The water treatment device according to claim 5, wherein the filtration device comprises a hollow fiber membrane module in which hollow fibers having a porous membrane made of PTFE (polytetrafluoroethylene) are converged.   The said filtration apparatus is connected with an electrolysis apparatus through piping, and the treated water containing the residual component which is not filtered is sent to the said electrolysis apparatus, and it discharges | emits, stores or reuses after an electrolysis process. The water treatment apparatus of any one of these.   The filtration device is connected to an electrolysis device through a pipe, and has a mechanism for supplying backwash water from the filtration device to the electrolysis device for electrolytic treatment, sterilizing, and discharging the system out of the system. Item 7. The water treatment device according to any one of items 6.   The filtration device is connected to an electrolytic device via a pipe, and the treated water filtered is supplied to the electrolytic device for electrolytic treatment, and the electrolytic solution electrolytically treated by the electrolytic device is washed in the filtration membrane of the filtration device The water treatment apparatus according to any one of claims 1 to 6, wherein the water treatment apparatus is supplied as water.   A temporary storage tank between the magnetic separation device and the filtration device, and a pump is provided in a pipe from the temporary storage tank to the filtration device to control the supply amount of treated water to the filtration device. The water treatment apparatus according to any one of claims 1 to 9. The amount of treated water in the magnetic separation device is set to 200 t / hour or more per installation volume of 1 m ³ , and the amount of treated water in the filtration device is set to from 100 t or more to 200 t or less / hour per installation volume of 1 m ^3. The water treatment apparatus according to any one of claims 10 to 10.   The ballast water treatment apparatus which is the ballast water which the water treatment apparatus of any one of Claim 1 thru | or 11 was mounted in the ship, and was stored by the said raw | natural water tank. Adding and mixing magnetic particles in raw water, and attaching the magnetic particles to the object to be removed contained in the raw water to impart magnetism; and
A magnetic separation step of magnetizing the object to be removed with magnetism applied to a magnetic filter and separating and removing the object to be removed from the raw water;
The treated water treated in the magnetic separation step is filtered through a filtration membrane having a smaller area for pores for capturing particles than the magnetic filter, and a filtration step for separating and removing remaining objects to be removed;
A water treatment method characterized by comprising: 90% or more of the object to be removed in the raw water is removed in the magnetic separation step, and the object to be removed and the magnetic substance in the treated water from which the object to be removed is separated and removed in the magnetic separation step in the filtration step by the filtration membrane. Remove the particles,
The water treatment method according to claim 13, wherein 98% or more of the object to be removed in the raw water is removed by the magnetic separation process at the former stage and the filtration process at the latter stage.   The raw water is ballast water stored in a ballast tank of a ship, and attaches the magnetic particles to an object to be removed consisting of plant microorganisms or animal microorganisms including algae floating and settled in the ballast water, and imparts magnetism. In addition to separation and removal in the magnetic separation step, to-be-removed objects including bacteria that have not been removed in the magnetic separation step are removed in the filtration step, and further, less than 0.1 μm in the ballast water not removed in the filtration step. The water treatment method according to claim 13 or 14, wherein bacteria are sterilized by electrolytic treatment. The treated water after the treatment by the filtering device has a living population per 1 m ³ of organisms having a minimum size of 50 μm or more and less than 10 living organisms per ml of organisms having a minimum size of 10 μm or more and less than 50 μm. Item 16. The water treatment method according to Item 15.

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