JP3334067B2 - Magnetic separation device and water treatment device with magnetic separation device - Google Patents

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 capable of removing and purifying unnecessary substances such as suspended solids in the liquid and floating organisms such as algae and fungi from the liquid to be treated at high speed, and a water purification device using the magnetic separation device.

[0002]

2. Description of the Related Art Conventionally, as a water purification device for raw water or wastewater of rivers and reservoirs to which this kind of solid-liquid separation technology is applied,
The magnetic separation apparatus described in JP-A-55-132684 having a two-stage magnetic separation step utilizing magnetic attraction is disclosed in JP-A-55-61979. Each of the processing methods described in the gazettes has been proposed.

[0003]

Problems to be Solved by the Invention JP-A-55-1326
In the apparatus described in Japanese Patent Publication No. 84, a ferromagnetic magnetic seed is added and dispersed in the wastewater in advance with respect to the wastewater in which most of the substances to be treated in the wastewater are non-magnetic and diamagnetic substances. A magnetic treatment method for aggregating a treated substance and a magnetic seed by the action of a coagulant or the like, magnetically filtering a magnetic aggregate of the treated substance and the magnetic seed, and separating a treated substance in wastewater from wastewater. Is described. Here, as the magnetic filtration means, a relatively large magnetic aggregate is magnetically settled in the first stage, and a magnetic aggregate having a relatively fine particle size that cannot be settled within a predetermined holding time is used. Is magnetically filtered at the second stage to obtain treated water.

In this method, the second-stage magnetic filtration device is a high gradient magnetic filter separation system in which a ferromagnetic filtration medium such as ferromagnetic stainless wool is externally excited by an excitation medium such as an electromagnet and a permanent magnet. After a certain amount of magnetic aggregates have accumulated in the ferromagnetic filtration medium, the purification operation is temporarily stopped, and a backwash operation is performed in which the magnetic aggregates accumulated in the ferromagnetic filtration medium are washed and desorbed using treated water, and the magnetic aggregates are removed. Is a method of temporarily accumulating backwash water containing water in a wash water tank, but this backwash water contains a large amount of treated water. Therefore, a step of reconcentrating the magnetic aggregates from the backwash water is required, but the treatment method is not described. Further, there is no description about a high-speed treatment method for the magnetic aggregates settled in the first stage.
It is not clear how to perform a high-speed purification operation of the entire apparatus.

On the other hand, Japanese Patent Application Laid-Open No. 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, a method using a rotating magnetic separation device in which a rotating disk having permanent magnets arranged on a circumference is installed in a washing water tank, and magnetic aggregates are separated directly from the washing water on the surface of the 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 closed by the magnetic aggregates in a short time, the backwashing operation cycle is shortened, and the purification operation is speeded up. There are drawbacks that are hindered. Also, 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 a rotating magnetic separation device, and it is difficult to speed up the purification of the backwash water.

[0006] However, in recent years, with the increase in the purification capacity of the water treatment apparatus, it has become necessary to increase the flow rate of the treated water in the magnetic separation unit, and to continuously purify and concentrate the backwash water. I have. As described above, a magnetic separator that captures and eliminates magnetic aggregates in two stages according to their size is advantageous for speeding up, but the first-stage magnetic separator continuously separates large magnetic aggregates. Must be excluded from the flow path.

[0007] Further, in order to increase the speed of the purifying apparatus including the concentration of the backwash water, it is necessary to speed up the separation of the magnetic aggregates from the backwash water.

[0008] It is an object of the present invention to provide a magnetic separation apparatus capable of increasing the flow rate of treated water in a magnetic separation section and shortening the purification operation stop time for backwashing to increase the purification processing amount.

[0009]

The first object of the present invention is to adsorb and capture magnetic aggregates in water to be treated by a high gradient magnetic filter in which a magnetic wire is filled in a magnetic field of a first magnet for generating a magnetic field. A first magnetic separation unit; and a second magnetic separation unit that adsorbs and captures magnetic aggregates in the water to be treated 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 result, the second magnetic separation unit, wherein disposed upstream of said first magnetic separation unit in the flow direction during the cleaning operation of the water to be treated, and said the second magnetic separation portion is adsorbed captured Equipped with a removing means for continuously removing magnetic aggregates
Of the water to be treated in the second magnetic separation unit.
Connecting the side of the first magnetic separation unit with the water to be treated
, A third magnetic separation via a washing liquid outlet pipe with a valve
The third magnetic separation unit is connected to the washing liquid outlet.
Move the backwash water flowing through the pipe relative to the backwash water.
The magnetic flux in the backwash water using the magnetic field of the third magnetic object.
While continuously collecting and capturing the aggregates,
The magnetic agglomerates adsorbed and captured by the third magnetic object are continuously
This is achieved by providing a removing means for removing the water .

[0010] The magnetic field generated by the first magnetic field generating magnet is
Magnetic properties of water to be treated by high gradient magnetic filter filled with fine wire
The first magnetic separation unit that adsorbs and captures aggregates and the water to be treated
The magnetic field of the second magnetic object that moves relatively to the water to be treated is
Magnetism to adsorb and capture magnetic aggregates in the water to be treated
And a second magnetic separation unit,
In the flow direction during the purification operation of the water to be treated, the first magnetic
The second magnetic separation unit is arranged on the upstream side of the separation unit, and
Removal for continuously removing the adsorbed and captured magnetic aggregates
A magnetic separation device comprising: a second magnetic separation device;
To supply the water to be treated
A valve is interposed in the water pipe, and the valve and the second magnetic separation unit are treated.
A cleaning liquid outlet with a valve installed in the water conduit between the water inlet side
Collect the backwash water that has passed through the second magnetic separation section via piping.
Connected to the treatment tank, and the treatment tank is also
(1) A valve is installed in the water pipe connected to the water discharge side of the magnetic separation unit.
May be connected via a .

[0011]

[0012]

[Function] The size of magnetic agglomerates and the content of magnetic powder formed in the pretreatment to the magnetic separation step are not constant, and the larger the magnetic agglomerates, the greater the content of magnetic powder and the attractive force to the magnetic surface. Is big. These large magnetic aggregates are adsorbed and captured on the magnet surface of the second magnetic separation unit even in a flow having a high flow velocity, and are continuously removed from the flow path by the removing means. The small magnetic agglomerates having a low magnetic powder content ride on the flow without being adsorbed and trapped on the magnet surface of the second magnetic separation unit, and flow into the first magnetic separation unit disposed downstream of the second magnetic separation unit. And enters 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 compared to the case without the second magnetic separation part, and the backwashing cycle can be reduced. More than twice as long.
Therefore, the backwash cycle can be lengthened, that is, the purification operation stop time for backwash can be shortened, and the purification processing amount 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. Separation can be performed at high speed.

When a third magnetic separation unit for magnetically separating magnetic aggregates from the washing water is provided, the backwash water of the first magnetic separation unit is temporarily stored in the third magnetic separation unit, and the backwash water is immediately stored after the backwash. First, the purification operation can be restarted using the second magnetic separation unit. Then, by performing the magnetic separation of the magnetic aggregates in the wash water temporarily stored in parallel with the purification operation in the third magnetic separation unit, the purification operation stop time for backwashing can be reduced.

[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 purification apparatus includes a water pipe 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 pipe 2, and a pump 4.
A raw water storage tank 5 connected to the discharge side of the raw water pipe 2A, and a magnetic separation device 10 connected to the raw water storage tank 5 by a water transmission pipe 2B.
0, the water pipe 2 with the valve 23 interposed in the magnetic separation device 100
A treatment water tank 24 connected at 2, a water guide pipe 25 having one end connected to the treatment water tank 24 and the other end guided to the reservoir 1;
And an air tank 29 connected to the magnetic separation device 100 by an air pipe 31 with a valve 30 interposed therebetween.
The description and description of a pump for flowing water, a head difference, and the like are omitted.

A magnetic separator 100 is connected to the raw water storage tank 5 by a water pipe 2B and is driven by a motor 10
1, a medicine adjusting device 7 connected to the water pipe 2B by a conduit 8, a second magnetic separation unit 110 connected to the water tank 13 by a water pipe 13, and a second magnetic separation unit. Part 110
A first magnetic separation unit 21 connected to a water outlet side of the water treatment system by a water guide pipe 20 having a valve 19 interposed therebetween; a valve 19 and a first magnetic separation unit 2
And a third magnetic separation unit 120 connected to the water guide pipe 20 by a cleaning liquid outlet pipe 26 with a valve 27 interposed therebetween. The water pipe 22 and the air pipe 31 are:
The first magnetic separation unit 21 is connected to the treated water discharge side.

The first magnetic separation section 21 is formed to include a first magnet for generating a magnetic field and a high gradient magnetic filter arranged in the magnetic field and filled with a magnetic fine wire, and the water to be treated is formed by the high gradient magnetic filter. It is configured to flow through. The first magnetic separation unit 21 is configured to enable backwashing of the high gradient magnetic filter.

The second magnetic separation section 110 has a rotating disk 15A supported by a large number of permanent magnet disks 16A embedded on the surface and having a rotating axis substantially horizontal, and the rotating disk 15A is installed therein and water to be treated flows through the rotating disk 15A. It includes a rotary magnetic separation tank 14A, a spatula 17A for scraping off surface adsorbed matter (magnetic aggregates) of the rotating disk 15A, and a sludge tank 18A arranged at a position where the material scraped off by the spatula 17A falls. It is composed of The water pipes 13 and 20 are connected to a rotary magnetic separation tank 14A. The rotating disk 15A is disposed so that the lower half thereof is in the water of the rotary magnetic separation tank 14A and the rotation axis is above the water surface, and the spatula 17A disposes the magnetic aggregate adsorbed to the rotating disk 15A on the water surface. It is located at the position where it is scraped off. The rotating disk 15A is continuously rotated in a predetermined direction by driving means (not shown).

The third magnetic separating section 120 has a rotating disk 15B supported by a large number of permanent magnet disks 16B embedded on the surface and having a rotating shaft substantially horizontal, and the rotating disk 15B is installed therein and temporarily stores backwash water. To the backwashing water tank 14B, a spatula 17B for scraping off the surface adsorbed material of the rotating disk 15B, a sludge tank 18B arranged at a position where the material scraped off by the spatula 17B falls, and a backwashing water tank 14B. And a water guide pipe 28 that is formed. The water pipe 2
Reference numeral 6 is connected to the backwash water tank 14B. The rotating disk 15B is disposed such that the lower half thereof is in the water of the backwashing treatment tank 14B and the rotating shaft is above the water surface, and the spatula 17B disposes the magnetic aggregate adsorbed to the rotating disk 15B on the water surface. It is located at the position where it is shaved off. Rotating disk 15B
Are continuously rotated in a predetermined direction by rotation driving means (not shown).

Next, the operation of the apparatus having the above configuration will be described. The magnetic aggregate is specifically produced by the following method. The water to be treated for water treatment is added as a pretreatment to the magnetic separation step, for example, by adding a magnetic powder such as triiron tetroxide and bansulfate or polyaluminum chloride as an aggregating agent, and stirring the mixture. Algae, fungi, and microorganisms are combined with the magnetic powder by the flocculant to form colloidal magnetic aggregates.

The raw water to be treated in the reservoir 1 is sucked up by a pump 4 through a water pipe 2 and temporarily stored in a raw water storage tank 5 through a filter 3 for removing large dust. To the raw water 6, a magnetic powder of triiron tetroxide and a coagulant such as polyaluminum chloride are added from a chemical preparation device 7 through a conduit 8, and the mixture is stirred by a stirrer 11 in a stirring tank 9, and the pretreatment including the magnetic aggregates Water 12 Pretreatment water 12 is a water pipe 13
And flows into the rotary magnetic separation tank 14A. In the rotary magnetic separation tank 14A, the rotating disk 15A is continuously rotating with its lower half below the water surface. A large number of magnetic objects, for example, permanent magnet disks 16A are embedded on the surface of the rotating disk 15A, and a magnetic aggregate containing a large amount of magnetic powder in the inflowed pretreatment water 12, mainly a large magnetic aggregate, is a permanent magnet disk. Adsorbed and captured on 16A surface. Then, the captured magnetic aggregates move on the liquid surface with the rotation of the rotating rotating disk 15A, and are separated from the magnet surface by the spatula 17A and settled in the sludge tank 18A before sinking below the liquid surface again. It is stored. The pretreatment water 12 flows in from one end of the rotary magnetic separation tank 14A and flows out from the other end to the water guide tube 20, but the flow direction in the rotary magnetic separation tank 14A is set to be opposite to the rotation of the rotary disk 15A. And the permanent magnet disk 16A of the rotating disk 15A
Move relatively to the water to be treated.

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

The magnetic separation performance of the high gradient magnetic filter of the first magnetic separation section 21 decreases as the magnetic aggregates are adsorbed. For this reason, after a certain amount of the magnetic aggregates are captured by the high gradient magnetic filter (or after performing the purifying 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 performance of the magnetic separation of the magnetic filter, a backwash for cleaning the filter is performed. The magnetic separation section on the right shows the backwash process. In the backwash, first, the valve 19 is closed and the valve 27 is opened to demagnetize the first magnet for generating a magnetic field. Next, a predetermined amount of the treated water in the treated water tank 24 flows back through the valve 23 through the high gradient magnetic filter as cleaning water, and the magnetic aggregates captured by the high gradient magnetic filter are discharged together with the cleaning water through the cleaning liquid outlet pipe 26. Then, the washing water (also called backwashing water) is stored in the backwashing treatment water tank 14B. During this cleaning, the valve 3 is removed from the air tank 29.
0. Air is supplied to the first magnetic separation unit through the air pipe 31 to perform air bubbling, thereby removing magnetic aggregates from the filter better.

A large number of magnetic objects, for example, permanent magnet disks 16B, are embedded in a rotating disk 15B provided in the backwashing treatment tank 14B, and a magnetic aggregate containing magnetic powder in the washing water, mainly a small magnetic disk, is provided. The aggregate of the aggregate is a permanent magnet disk 16
Captured on the B surface. The magnetic agglomerates captured on the surface of the permanent magnet disk 16B move on the liquid surface with the rotation of the rotating disk 15B.
At B, it is stripped off from the magnet surface and stored in the sludge tank 18B. The washing water from which the magnetic aggregate has been separated passes through the water pipe 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. However, in the magnetic separation in the third magnetic separation unit 120, the washing 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 of the respective tanks and subjected to a dehydration treatment, after which magnetic powder is collected, discarded in a landfill, or incinerated.

After the backwash, the valves 27 and 30 are closed, and the valve 19 is opened to fill the magnetic separation section 21 with the pretreated water and the purification operation is resumed. 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.

As described above, according to the present embodiment, the pretreated water 1
Most of the magnetic aggregates in 2 are large magnetic aggregates, and most of them are continuously captured and continuously removed by the second magnetic separation unit of the magnet rotation type. Therefore, the amount of magnetic aggregates deposited on the high gradient magnetic filter can be reduced to half or less, and the backwashing cycle becomes twice or longer. In this way,
In the present embodiment, the backwashing cycle is made as long as possible, and the magnetic separation of the magnetic aggregates from the washing water during the backwashing and the purification operation can be performed in parallel, so that the purification treatment amount can be increased. Also,
Since the magnetic aggregates contained in the backwash water are combined with each other to increase in size, the efficiency of magnetic separation by the rotating disk 15B is also improved, and the speed of the separation process can be increased.

FIG. 2 shows a second embodiment according to the present invention.
This 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 provided on the downstream side of the valve 19 during the cleaning operation and on the upstream side of the valve 27 during the backwash. And the function of the third magnetic separation unit 120 in the first embodiment is also performed by 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 outlet water pipe 22 of the first magnetic separation unit 21 by a water pipe 34 with a valve 33 interposed.

According to the present embodiment, the number of rotary magnetic separation tanks can be reduced, the size of the apparatus can be reduced, and the amount of washing water during backwashing is sufficiently smaller than that during the purification operation. Since the small magnetic aggregates deposited on the filter are slow and stay in the filter in the high magnetic field for a long time, the respective magnetic aggregates are combined and become large, and the magnetic aggregates in the washing water are removed at the time of back washing. It can be captured with high probability in the rotary magnetic separation tank 14. Thus, the backwash water is freed of magnetic aggregates and stored once in the treatment tank 32 via the valve 27 and returned to the reservoir 1 or alternatively, the valve 33, the water pipe 34
Used as backwash water. The separation and backwashing unit 35 including the first magnetic separation unit 21, the second magnetic separation unit 110, the treatment water tank 32, the valves 19, 27, 33, and the water conduit connecting them should be modularized. It is convenient.

FIG. 3 shows a third embodiment according to the present invention.
This drawing is different from FIG. 2 in that the separation backwashing unit 35 is arranged in a plurality of rows, for example, two units of 35A and 35B are arranged in parallel, and one of the separation backwashing units 35A is a valve 33 during the purification operation.
Open A and close valve 36A. At this time, the separation backwash unit 35B is performing the backwash operation, the valve 33B is closed, and the valve 36B is open. According to the present embodiment, the separation backwash unit 35
By switching between A and 35B for operation, there is an effect that the purification operation can be continuously performed.

In the above embodiment of the present invention, a case where a permanent magnet is used as a magnetic object has been described. However, the present magnetic object is supplied with a 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 superconductive coil. The external magnet is a high gradient magnetic separator 21.
A similar effect is produced by the magnet constituting the above. Also,
This device can be installed on a ship, on a car, underground, and the like.

The above-mentioned raw water is water containing impurities such as rivers, dams, lakes and marshes, seawater, reservoirs, industrial wastewater, sewage, rainwater, and the like. Not only solid suspended solids, algae and fungi described above, but also objects such as organic matter, inorganic matter and microorganisms, metallic matter, non-metallic matter, soil, radioactive material, metal ions and the like. In particular, after adding divalent iron ions such as ferrous sulfate and alkali to raw water containing heavy metal ions to co-precipitate heavy metal ions with the precipitate of ferrous hydroxide, oxidize with air to precipitate the ferrite. Become The heavy metal can be magnetically separated by the ferrite formation. In this case, if the purpose is to separate only heavy metal ions, no coagulant is required. Therefore, in this case, ferrous sulfate, an alkali solution, and air may be injected into the raw water as a pretreatment, and the raw water may be treated in the stirring tank, and then the pretreatment water may be guided to the magnetic separation unit.

[0032]

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

[Brief description of the 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 configuration of a magnetic separator according to a second embodiment of the present invention.

FIG. 3 is a system diagram showing a main 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 guide tube 3 filter 4 pump 5 raw water storage tank 6 raw water 7 chemical preparation device 8 conduit 9 stirring tank 10 motor 11 stirrer 12 pretreatment water 13 water guide pipe 14, 14
A, Rotary magnetic separation tank 14B Backwashing 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 pipe 21 First magnetic separation part 22 Water pipe 23 Valve 24 Treatment water tank 25 Water pipe 26 Cleaning liquid outlet pipe 27 Valve 28 Water pipe 29 Air tank 30 Valve 31 Air pipe 32 Treatment water tank 33, 33
A, 33B valve 34 water pipe 35, 35A, 35B separation backwashing unit 36A, 36B valve 100 magnetic separator 110 second magnetic separator 120 third
Magnetic separation unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-218493 (JP, A) JP-A-55-132684 (JP, A) JP-A-55-61979 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) B01D 35/06 B03C 1/00-1/32

Claims (3)

(57) [Claims] A first magnetic separation unit for adsorbing and capturing magnetic aggregates in the water to be treated by a high gradient magnetic filter in which a magnetic thin wire is filled in a magnetic field of a first magnet for generating a magnetic field; A second magnetic separation unit for adsorbing and capturing magnetic aggregates in the water to be treated using a magnetic field of a second magnetic object relatively moving with water, wherein the second magnetic separation unit comprises A magnetic device comprising: a removing unit disposed upstream of the first magnetic separation unit in a flow direction during a water purification operation, wherein the second magnetic separation unit continuously removes the magnetic aggregate adsorbed and captured. In the separation device, a third magnetic separation unit is connected to a pipe connecting a water discharge side of the second magnetic separation unit and a water inlet side of the first magnetic separation unit through a cleaning liquid outlet pipe provided with a valve. Connected to the third magnetic separation section, and flows in through the cleaning liquid outlet pipe. A magnetic field of a third magnetic object that moves relatively to the backwash water, and continuously adsorbs and captures magnetic aggregates in the backwash water, and the third magnetic object A magnetic separation device comprising a removing means for continuously removing the magnetic aggregate adsorbed and captured on the magnetic separation device. 2. A first magnetic separation unit for adsorbing and capturing magnetic agglomerates in water to be treated by a high gradient magnetic filter filled with a magnetic wire in a magnetic field of a first magnet for generating a magnetic field, and the water to be treated is treated in the water to be treated. A second magnetic separation unit for adsorbing and capturing magnetic aggregates in the water to be treated using a magnetic field of a second magnetic object relatively moving with water, wherein the second magnetic separation unit comprises A magnetic device comprising: a removing unit disposed upstream of the first magnetic separation unit in a flow direction during a water purification operation, wherein the second magnetic separation unit continuously removes the magnetic aggregate adsorbed and captured. In the separation device, a valve is interposed in a water supply pipe connected to the second magnetic separation unit to supply the water to be treated and supplies the water to be treated, and the valve and the second magnetic separation unit are provided with the water to be treated. Through the washing liquid outlet pipe provided with a valve, A treated water tank containing the backwash water that has passed through the magnetic separation unit is connected, and the treated water tank is also connected via a valve to a water pipe connected to the treated water outlet side of the first magnetic separation unit. A magnetic separation device. 3. A pump means for pumping water to be treated from a water source, a raw water storage tank for temporarily storing the water to be pumped, solid suspended matter and algae contained in the water to be stored stored in the raw water storage tank. A magnetic separation device for magnetically separating suspended organisms composed of fungi as magnetic aggregates, a treatment water tank provided to be connected to the magnetic separation device and temporarily storing treated water from which the magnetic aggregates have been separated, and a treatment water tank. A water supply means for returning treated water to the water source,
A water purification device comprising a magnetic separation device, wherein the magnetic separation device is the device according to claim 1.