JPH0975631A - Magnetic separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the purifying treatment quantity of a magnetic separator by making a backwashing cycle as long as possible. SOLUTION: A magnet rotary type second magnetic separation part 110 is arranged on the upstream side at a time of the purifying operation of a high grade magnetic type filter type first magnetic separation part 21 and a magnet rotary type third magnetic separation port 120 is arranged on the downstream side of the first magnetic separation part 21 at a time of the backwashing of the first magnetic separation part 21 and the second and third magnetic separation parts 110, 120 are constituted so as to contain spatulas 17a, 17b continuously cutting off magnetic flock from attraction surfaces. By this constitution, the quantity per a time of the magnetic floc accumulated on the high grade filters is reduced to make a backwashing cycle long and, since magnetic floc can be separated from washing water at a time of backwashing at a high speed, the purifying treatment quantity of a magnetic separator can be increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic separation device,
In particular, the present invention relates to a magnetic separation device that can remove and purify suspended solids in a liquid to be treated and unnecessary substances such as floating organisms such as algae and fungi at a high speed, and a water purification device using the magnetic separation device.

[0002]

2. Description of the Related Art Conventionally, as a water purifying apparatus for raw water such as rivers and reservoirs, waste water, etc., to which this kind of solid-liquid separation technology is applied,
The magnetic separation apparatus described in JP-A-55-132684, which has a two-step magnetic separation process utilizing magnetic attraction, and the dehydration-concentration method after separation are described in JP-A-55-61979. The processing methods described in the publications have been proposed.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the device described in Japanese Patent Publication No. 84, the magnetic material of ferromagnetic is added to and dispersed in the wastewater in advance in the wastewater in which most of the substances to be treated in the wastewater are non-magnetic and diamagnetic substances. A magnetic treatment method in which a treatment substance and magnetic seeds are aggregated by the action of an aggregating agent or the like, the magnetic aggregates of the treatment substance and magnetic seeds are magnetically filtered, and the treatment substance in wastewater is separated from wastewater. Is listed. Here, as this magnetic filtering means, a relatively large magnetic aggregate is magnetically settled in the first stage, and a magnetic aggregate having a relatively fine particle size that could not be settled within a predetermined retention time. Is magnetically filtered in the second stage to obtain treated water.

In this method, the second-stage magnetic filtering device is a high gradient magnetic filter separation system in which a ferromagnetic filtering medium such as ferromagnetic stainless wool is externally excited by an exciting medium such as an electromagnet and a permanent magnet, After some amount of magnetic aggregates have accumulated in the ferromagnetic filtration medium, the cleaning operation is temporarily stopped, and the backwash operation is performed to wash and desorb the magnetic aggregates accumulated in the ferromagnetic filtration medium using the treated water. This is a method of temporarily storing backwash water containing water in the wash water tank, but this backwash water contains a lot of treated water. Therefore, a step of reconcentrating the magnetic aggregate from the backwash water is necessary, but the treatment method thereof is not described. Further, there is no description about the high-speed treatment method of the magnetic aggregates precipitated in the first step, and if it is left as it is, it includes the treatment of backwash water,
It is not clear how to perform high-speed purification operation for the entire device.

On the other hand, JP-A-55-61979 discloses a high-speed treatment method of washing water containing magnetic aggregates after backwashing in a high gradient magnetic separation system. this is,
For example, it is a method using a rotating magnetic separation device in which a rotating disk having permanent magnets arranged on the circumference is installed in a washing water tank, and magnetic aggregates are directly separated from the washing water on the surface of this permanent magnet. However, in this known example, since all the magnetic aggregates are captured and accumulated by the high gradient magnetic separator, the separation unit is clogged with the magnetic aggregates in a short time, the backwash operation cycle becomes short, and the purification operation can be speeded up. It has the drawback of being hindered. Further, since all of the magnetic aggregates in the raw water are contained in the backwash water, a large amount of magnetic aggregates must be separated by the rotary magnetic separation device, and it is difficult to speed up the backwash water purification.

However, in recent years, as the purification treatment amount of the water treatment apparatus has been increased, it is necessary to increase the flow velocity of the treated water in the magnetic separation section and to continuously purify and concentrate the backwashing wash water. There is. As described above, a magnetic separation device that captures and eliminates magnetic agglomerates in two stages according to its size is advantageous for speeding up, but the first-stage magnetic separator continuously separates large magnetic agglomerates. Must be excluded from the flow path.

Further, in order to speed up the purification apparatus including the concentration of the backwash water, it is necessary to speed up the separation of the magnetic aggregates from the backwash water.

An object of the present invention is to provide a magnetic separation apparatus which can increase the flow rate of treated water in the magnetic separation section and shorten the purification operation stop time for backwashing to increase the purification treatment amount.

[0009]

As a first means, the above object is to adsorb and capture magnetic aggregates in the water to be treated by a high gradient magnetic filter in which magnetic fine wires are filled in the magnetic field of the first magnetic field generating magnet. A first magnetic separation unit; and a second magnetic separation unit that adsorbs and captures magnetic aggregates in the water to be treated by using a magnetic field of a second magnetic object that moves in the water to be treated relative to the water to be treated. In the magnetic separation device, the second magnetic separation unit is arranged upstream of the first magnetic separation unit in the flow direction during the purification operation of the water to be treated, and is adsorbed to the second magnetic separation unit. This is achieved by providing a removing means for continuously removing the captured magnetic aggregates.

In addition to the above-mentioned first means, backwash water is introduced downstream of the first magnetic separation section in the flow direction of the backwash water during the high gradient magnetic filter backwash operation of the first magnetic separation section. A third magnetic separation unit for continuously adsorbing and capturing magnetic aggregates in the backwash water by using a magnetic field of a third magnetic object that moves relatively to the backwash water is disposed, and the third magnetic separation unit is provided. A removal means for continuously removing the magnetic aggregate adsorbed and captured by the above may be provided.

Further, in the above-mentioned first means, a pipe for guiding the backwash water that has passed through the high gradient magnetic filter to the second magnetic separator during the high gradient magnetic filter backwash operation of the first magnetic separator is provided. Furthermore, a pipe may be provided to take out the backwash water that has passed through the second magnetic separation unit from the second magnetic separation unit.

[0012]

[Function] The size of the magnetic aggregates and the content of the magnetic powder formed in the pretreatment for the magnetic separation step are not constant, and the larger the magnetic aggregate, the larger the content of the magnetic powder and the attraction force to the magnetic surface. Is big. These large magnetic agglomerates are adsorbed and captured on the magnet surface of the second magnetic separation unit even in a flow having a high flow rate, and are continuously removed to the outside of the flow path by the removing means. The small-sized magnetic agglomerates containing a small amount of magnetic powder are not adsorbed and captured on the magnet surface of the second magnetic separation unit and ride on the flow to the first magnetic separation unit disposed downstream of the second magnetic separation unit. It flows in and is captured by the high gradient magnetic filter. Most of these magnetic agglomerates are large magnetic agglomerates, and the amount of magnetic agglomerates deposited on the high gradient magnetic filter can be reduced to less than half, and the backwash cycle can be reduced as compared with the case without the second magnetic separation unit. It is more than twice as long.
Therefore, the backwash cycle can be extended, that is, the cleaning operation stop time for backwashing can be shortened, and the amount of purification processing can be increased. In addition, the amount of small magnetic aggregates accumulated in the high gradient magnetic filter is smaller than the total amount of magnetic aggregates in the raw water by the amount of large magnetic aggregates removed, so that the amount of magnetic aggregates from the wash water is reduced. The separation can be performed at high speed.

When the third magnetic separation unit for magnetically separating the magnetic aggregates from the wash water is provided, the backwash water of the first magnetic separation unit is temporarily stored in the third magnetic separation unit, and immediately after the backwash is finished, The cleaning operation can be restarted using the first and second magnetic separation units. By performing the magnetic separation of the magnetic aggregates in the wash water temporarily stored in parallel with the cleaning operation in the third magnetic separation section, the cleaning operation stop time for backwashing can be shortened.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIG. The illustrated water purifying apparatus includes a water conduit 2 having one end opened below the water surface of a reservoir 1 and a filter 3 interposed therebetween, a pump 4 having a suction side connected to the other end of the water conduit 2, and a pump 4
The raw water storage tank 5 connected to the discharge side of the raw water pipe 2A, and the magnetic separation device 10 connected to the raw water storage tank 5 by the water transport pipe 2B.
0 and the water conduit 2 in which the valve 23 is provided in the magnetic separation device 100.
2, a treated water tank 24 connected at 2, and a water conduit 25 having one end connected to the treated water tank 24 and the other end led to the reservoir 1.
An air tank 29 is connected to the magnetic separation device 100 by an air pipe 31 having a valve 30 interposed therebetween.
It should be noted that description and description of a pump for flowing water, a head difference, and the like are omitted.

The magnetic separator 100 is a stirrer 1 which is connected to the raw water storage tank 5 by a water conduit 2B and driven by a motor 10.
1, a stirring tank 9 having 1; a medicine adjusting device 7 connected to the water guiding tube 2B by a conduit 8; a second magnetic separation unit 110 connected to the stirring tank 9 by a water guiding tube 13; and a second magnetic separation. Part 110
Magnetic separation part 21 connected to a treated water outlet side by a water conduit 20 having a valve 19 interposed between the valve 19 and the first magnetic separation part 2
The third magnetic separation part 120 is connected to the water conduit 20 between the first and second parts by the cleaning liquid outlet pipe 26 having the valve 27 interposed therebetween. The water conduit 22 and the air pipe 31 are
It is connected to the treated water outlet side of the first magnetic separation unit 21.

The first magnetic separation unit 21 is formed by including a first magnet for generating a magnetic field and a high-gradient magnetic filter arranged in the magnetic field and filled with magnetic fine wires, and the water to be treated has the high-gradient magnetic filter. It is designed to flow through. The first magnetic separation unit 21 is adapted to allow backwashing of the high gradient magnetic filter.

The second magnetic separation unit 110 has a rotary disk 15A in which a large number of permanent magnet disks 16A are embedded on the surface and is supported with its rotary shaft substantially horizontal, and the rotary disk 15A is internally provided so that water to be treated flows through. Includes a rotary magnetic separation tank 14A, a spatula 17A for scraping off surface adsorbates (magnetic agglomerates) on the rotary disk 15A, and a sludge tank 18A arranged at a position where the scraped off material by the spatula 17A falls. It is composed of. The water conduits 13 and 20 are connected to a rotary magnetic separation tank 14A. Further, the rotating disk 15A is arranged such that the lower half of the rotating disk 15A is in the water of the rotary magnetic separation tank 14A so that the rotating shaft comes out above the water surface, and the spatula 17A holds the magnetic aggregate adsorbed on the rotating disk 15A on the water surface. It is placed at the position where it will be scraped off. The rotating disk 15A is continuously rotated in a predetermined direction by a driving unit (not shown).

The third magnetic separation part 120 has a rotary disk 15B having a large number of permanent magnet disks 16B embedded on its surface and supported with its rotary shaft substantially horizontal, and the rotary disk 15B is internally provided to store backwash water temporarily. Connected to the backwashing water tank 14B, the backwashing water tank 14B, the spatula 17B for scraping off the surface adsorbed matter of the rotating disk 15B, the sludge tank 18B arranged at the position where the scraped off material is dropped. The water guiding pipe 28 is provided. The water conduit 2
6 is connected to the backwashing water tank 14B. The rotating disk 15B is arranged such that the lower half of the rotating disk 15B is in the water of the backwashing water tank 14B and the rotating shaft is above the water surface, and the spatula 17B is provided with the magnetic aggregate adsorbed on the rotating disk 15B on the water surface. It is located at the position where it is scraped off. Rotating disk 15B
Is continuously rotated in a predetermined direction by a rotation driving means (not shown).

Next, the operation of the apparatus having the above structure will be described. The magnetic aggregate is specifically prepared by the following method. The water to be treated is subjected to pretreatment for the magnetic separation step, for example, magnetic powder such as ferrosoferric oxide and vanadium sulfate or polyaluminum chloride as a coagulant are added and stirred, and solid suspension in raw water or Algae, fungi, and microorganisms are bound to magnetic powder by a flocculating agent to form a colloidal magnetic aggregate.

Raw water to be treated in the reservoir 1 is sucked up by a pump 4 via a water conduit 2, and is temporarily stored in a raw water storage tank 5 through a filter 3 for removing large dust. To this raw water 6, a magnetic powder of ferric tetroxide and an aggregating agent such as polyaluminum chloride are added from a chemical adjusting device 7 through a conduit 8 and agitated by an agitator 11 in an agitation tank 9 to perform a pretreatment containing magnetic agglomerates. It becomes water 12. The pretreated water 12 is a water conduit 13
And flows into the rotary magnetic separation tank 14A. In the rotary magnetic separation tank 14A, the rotary disk 15A is continuously rotated with its lower half portion below the water surface. A large number of magnetic objects, for example, permanent magnet discs 16A are embedded on the surface of the rotating disc 15A, and magnetic aggregates containing a large amount of magnetic powder in the pretreated water 12 that has flowed in, mainly large magnetic aggregates, are permanent magnet discs. Adsorbed and captured on the 16A surface. Then, the captured magnetic agglomerates move above the liquid surface with the rotation of the rotating rotating disk 15A, and before being submerged below the liquid surface again, they are stripped off from the magnet surface by the spatula 17A and placed in the sludge tank 18A. It can be stored. The pretreated water 12 flows in from one end of the rotary magnetic separation tank 14A and flows out from the other end to the water conduit 20, but the flow direction in the rotary magnetic separation tank 14A is set in the opposite direction to the rotation of the rotary disk 15A. The permanent magnet disk 16A of the rotating disk 15A
Are moved relative to the water to be treated.

Pretreated water 1 from which large magnetic aggregates have been removed
2 passes through the water conduit 20 through the valve 19 and the first magnetic separation unit 2
1 into the high gradient magnetic filter, and the remaining magnetic aggregates are captured by the high gradient magnetic filter. The raw water purified by removing the magnetic aggregates is temporarily stored as treated water in the treated water tank 24 through the water guiding pipe 22 and the valve 23, and is returned to the reservoir 1 through the water guiding pipe 25 serving as a water feeding means.

In the high gradient magnetic filter of the first magnetic separation section 21, the magnetic separation performance deteriorates as the magnetic aggregates are adsorbed. Therefore, after a certain amount of magnetic aggregates are captured by the high-gradient magnetic filter (or after performing a cleaning operation for a certain period of time, or when the differential pressure before and after the high-gradient magnetic filter exceeds a predetermined value), the high gradient In order to restore the magnetic separation performance of the magnetic filter, backwashing is performed to clean the filter. The magnetic separator on the right shows the backwash process. In backwashing, first, the valve 19 is closed and the valve 27 is opened to demagnetize the first magnetic field generating magnet. Then, the treated water in the treated water tank 24 is made to flow back through the valve 23 as washing water to the high gradient magnetic filter by a predetermined amount, and the magnetic aggregates captured by the high gradient magnetic filter are caused to flow out through the washing liquid outlet pipe 26 together with the washing water. , Wash water (also referred to as backwash water) is stored in the backwash treated water tank 14B. During this cleaning, the air tank 29 to the valve 3
0, air is supplied to the first magnetic separation unit through the air pipe 31, air bubbling is performed, and magnetic aggregates are better removed from the filter.

A large number of magnetic objects, for example, permanent magnet disks 16B are embedded in the rotating disk 15B provided in the backwashing water tank 14B, and magnetic aggregates containing magnetic powder in the wash water, mainly small magnetic particles. The assembly of the assembly is a permanent magnet disk 16
It is captured on the B surface. The magnetic agglomerates captured on the surface of the permanent magnet disc 16B move to the liquid surface as the rotating disc 15B rotates, and before they sink below the water surface again, the spatula 17
It is stripped off from the magnet surface at B and stored in the sludge tank 18B. The washing water from which the magnetic aggregates have been separated passes through the water conduit 28 and is returned to the water source or used as washing water. Second
In the magnetic separation of the magnetic separation unit 110, the pretreated water 12
Flows in a fixed direction in the rotary magnetic separation tank 14A, but in the magnetic separation in the third magnetic separation unit 120, the wash water is stored in the backwash treatment water tank 14B and is stationary. Not flowing.

The magnetic agglomerates in the sludge tanks 18A and 18B are carried out from the respective tanks, subjected to dehydration treatment, and then the magnetic powder is recovered, discarded in a landfill or the like, or incinerated.

After backwashing, the valves 27 and 30 are closed and the valve 19 is opened to fill the magnetic separation portion 21 with the pretreated water and the purification operation is restarted. At the same time, the magnetic separation of the wash water stored in the backwash water tank 14B is performed in parallel with the purification operation using the first magnetic separation unit and the second magnetic separation unit.

Thus, according to this embodiment, the pretreated water 1
Most of the magnetic agglomerates in 2 are large magnetic agglomerates, and most of them are continuously captured and continuously removed by the second magnetic separation unit of the magnet rotation system. Therefore, the amount of magnetic aggregates deposited on the high-gradient magnetic filter can be reduced to less than half, and the backwash cycle also becomes longer than twice. In this way,
In this embodiment, the backwash cycle can be made as long as possible, and the magnetic separation of the magnetic aggregates from the wash water during the backwash and the cleaning operation can be performed in parallel, so that the amount of cleaning treatment can be increased. Also,
Since the magnetic aggregates contained in the backwash water are combined with each other and are large in size, the efficiency of magnetic separation by the rotating disk 15B is also improved, and the separation process can be sped up.

A second embodiment according to the present invention is shown in FIG.
The present embodiment is different from the embodiment shown in FIG. 1 in that the second magnetic separation unit 110 including the rotary magnetic separation tank 14 is located downstream of the valve 19 during purification operation and upstream of the valve 27 during backwashing. The third magnetic separation unit 120 in the first embodiment has the function of the second magnetic separation unit 110. Also,
In this embodiment, the third magnetic separation unit 120 is provided downstream of the valve 27.
Instead, a treated water tank 32 is placed, and the treated water tank 32 is connected to the water conduit 22 on the outlet side of the first magnetic separation unit 21 by a water conduit 34 having a valve 33 interposed.

According to this embodiment, the number of rotary magnetic separation tanks can be reduced, the apparatus can be downsized, and the amount of washing water in backwashing is sufficiently smaller than that in the purifying operation. The small magnetic agglomerates that are slow and deposited on the filter stay in the filter in a high magnetic field for a long time, so each magnetic agglomerate binds and becomes large, and the magnetic agglomerates in the wash water are washed away during backwashing. It can be captured with high probability by the rotary magnetic separation tank 14. Therefore, the backwash water is removed of magnetic aggregates and is once stored in the treated water tank 32 through the valve 27 and returned to the reservoir 1, or the valve 33 and the water conduit 34.
Used as water for backwashing. It should be noted that it is better to modularize the separation backwash unit 35 including the first magnetic separation unit 21, the second magnetic separation unit 110, the treated water tank 32, the valves 19, 27, 33 and the water pipes connecting them. It is convenient.

A third embodiment according to the present invention is shown in FIG.
2 is different from FIG. 2 in that the separation backwash unit 35 is arranged in a plurality of rows, for example, two units 35A and 35B are arranged in parallel, and one of them, for example, the valve 33 in the separation backwash unit 35A during the cleaning operation.
Open A and close valve 36A. At this time, the separation backwash unit 35B is in the backwash operation, and the valve 33B is closed and the valve 36B is opened. According to this embodiment, the separation backwash unit 35
By switching between A and 35B for operation, the purifying operation can be continuously performed.

In the above embodiments of the present invention, the case where a permanent magnet is used as the magnetic object has been described. However, the present magnetic object is a normal conducting coil, a superconducting coil or a normal conducting coil which is supplied with an electric current to generate a magnetic field. The same effect is obtained even with a metal body magnetized by the magnetic field of an external magnet such as a conductive coil or a superconducting coil. In addition, the external magnet is a high gradient magnetic separator 21.
The same effect can be obtained with the magnet constituting the. Also,
This device can be installed onboard, onboard, underground, etc.

The raw water mentioned above is water containing impurities such as rivers, dams, lakes, seawater, reservoirs, industrial wastewater, sewage, rainwater, etc. Impurities (substances to be removed) are Not only the solid suspended matter, algae, and fungi described above, but also objects such as organic matter, inorganic matter, microorganisms, metal matter, non-metal matter, soil, radioactive material, metal ion and the like are included. In particular, divalent iron ions such as ferrous sulfate and alkali are added to raw water containing heavy metal ions to coprecipitate heavy metal ions with the precipitate of ferrous hydroxide, and then oxidized with air to precipitate the precipitates with ferrite. Turn into. This ferritization allows the heavy metal to be magnetically separated. In this case, if the purpose is to separate only the heavy metal ions, the aggregating agent becomes unnecessary. Therefore, in this case, ferrous sulfate, an alkaline solution, and air are injected into the raw water as pretreatment and treated in a stirring tank, and then the pretreated water may be introduced to the magnetic separation unit.

[0032]

According to the present invention, since the amount of magnetic aggregates deposited on the high gradient magnetic filter per unit time can be reduced,
The backwash cycle can be lengthened, and the average amount of purification treatment per unit time of the magnetic separator can be increased.

[Brief description of drawings]

FIG. 1 is a system diagram showing a main configuration of a magnetic separation device according to a first embodiment of the present invention.

FIG. 2 is a system diagram showing a main part configuration of a magnetic separation device according to a second embodiment of the present invention.

FIG. 3 is a system diagram showing a main part configuration of a magnetic separation device according to a third embodiment of the present invention.

[Explanation of symbols]

1 Reservoir 2,2A, 2
B water conduit 3 filter 4 pump 5 raw water storage tank 6 raw water 7 chemical regulator 8 conduit 9 stirring tank 10 motor 11 stirrer 12 pretreatment water 13 water guiding pipe 14, 14
A, rotary magnetic separation tank 14B backwash water tank 15,15
A, 15B Rotating disk 16, 16A, 16B Permanent magnet disk, 17, 17
A, 17B Spatula 18, 18A, 18B Sludge tank 19 Valve 20 Water transfer pipe 21 First magnetic separation part 22 Water transfer pipe 23 Valve 24 Treatment water tank 25 Water transfer pipe 26 Cleaning liquid outlet pipe 27 Valve 28 Water transfer pipe 29 Air tank 30 Valve 31 Air pipe 32 treated water tank 33, 33
A, 33B valve 34 water conduit 35, 35A, 35B separation backwash unit 36A, 36B valve 100 magnetic separation device 110 second magnetic separation unit 120 third
Magnetic separation unit

Claims (5)

[Claims] 1. A first magnetic separation part for adsorbing and capturing magnetic aggregates in the water to be treated by a high gradient magnetic filter in which magnetic wires are filled in the magnetic field of the first magnet for generating a magnetic field, and the water to be treated is treated as described above. A magnetic separation device comprising: a second magnetic separation unit that adsorbs and captures a magnetic aggregate in water to be treated by using a magnetic field of a second magnetic object that moves relatively to water. A removal for continuously removing the magnetic aggregates that are disposed upstream of the first magnetic separation portion in the flow direction during the purification operation of the water to be treated and that the second magnetic separation portion has adsorbed and captured. A magnetic separation device comprising means. 2. A rotary disc in which a large number of permanent magnets are embedded in the surface of the second magnetic separation part and which is rotationally driven with its rotary shaft substantially horizontal; and a rotary type in which this rotary disc is installed and through which water to be treated flows. A magnetic separation tank, and a spatula that is a removing means for continuously scraping off an object magnetically adsorbed on the surface of the rotating disk.
And a sludge tank disposed at a position where what is scraped off by the spatula falls, the lower half part of the rotating disk is in the water of the rotary magnetic separation tank, and the rotating shaft is above the water surface. 2. The magnetic separation device according to claim 1, wherein the spatula is arranged so as to appear on the water surface, and the spatula is arranged at a position where the object adsorbed to the rotating disk is scraped off on the water surface. 3. The backwash water is moved relatively to the backwash water downstream of the first magnetic separator in the flow direction of the backwash water during the high gradient magnetic filter backwash operation of the first magnetic separator. 3rd to do
A third magnetic separation unit for continuously adsorbing and capturing magnetic aggregates in the backwash water by using a magnetic field of a magnetic object is disposed, and the third magnetic separation unit continuously adsorbs and captures the magnetic aggregates. The magnetic separation device according to claim 1 or 2, further comprising a removing unit for removing the magnetic separation device. 4. A pipe for guiding the backwash water that has passed through the high-gradient magnetic filter to the second magnetic separator during the high-gradient magnetic filter backwash operation of the first magnetic separator, and the second magnetic separator.
The magnetic separation device according to claim 1 or 2, further comprising a pipe for extracting the backwash water that has passed through the magnetic separation unit from the second magnetic separation unit. 5. A pump means for pumping treated water from a water source, a raw water storage tank for temporarily storing the pumped treated water, and a solid suspended matter and algae contained in the treated water stored in the raw water storage tank. A magnetic separation device for magnetically separating suspended organisms composed of fungi as a magnetic aggregate, a treated water tank provided to be connected to the magnetic separator for temporarily storing the treated water from which the magnetic aggregate has been separated, and the treated water tank In a water purification device comprising a water supply means for returning treated water to the water source,
A water purification device, wherein the magnetic separation device is the device according to any one of claims 1 to 4.