JP2016013522A - Water treatment system and water treatment method - Google Patents

Abstract

A water treatment system and a water treatment method are provided that purify water to be treated using magnetic particles, efficiently separate the used magnetic particles from a substance to be removed, and allow reuse. In a water treatment system for removing a solid removal target substance contained in water to be treated, the water to be treated and magnetic particles are mixed to form an agglomerate containing the removal target substance and magnetic particles. Aggregate forming means, aggregate separating means for obtaining purified treated water by separating the aggregate from the water to be treated, and crushing means for crushing the aggregate by applying centrifugal force to the separated aggregate Separating and collecting means for separating and collecting the magnetic particles obtained by crushing using magnetic force, and reusing means for reusing the magnetic particles collected by the separating and collecting means for forming aggregates; , Having a water treatment system. [Selection] Figure 1

Description

  Embodiments described herein relate generally to a water treatment system and a water treatment method.

  In recent years, effective use of water resources is required due to industrial development and population growth. For that purpose, reuse of wastewater such as industrial wastewater is very important. In order to achieve these, it is necessary to purify water, that is, to separate unnecessary substances from the water.

  As described above, various methods are known for separating unnecessary substances from water, such as membrane separation, centrifugation, activated carbon adsorption, ozone treatment, agglomeration, and removal of suspended substances with a filter aid. It is done. By such various methods, chemical substances having a great influence on the environment such as phosphorus and nitrogen contained in water can be removed, and oils and clays dispersed in water can be removed.

  In such a purification technique, attempts have been widely made to mix a magnetic substance into a drug / adsorbent to be added and separate and recover it by magnetic force. For example, a flocculant and a magnetic substance are added to form a magnetic floc that aggregates the removed substances in water, and a technique of separating with a magnet or a filter aid containing a magnetic substance is formed on the filter for filtration. A technique for cleaning and regenerating a filter aid is known.

  And in such a water treatment method, the technology of reusing the magnetic material is important, and in that case, it is necessary to enhance the efficient separation ability of the magnetic material and the removed substance, and it depends on the magnetic drum and the transfer pump. There are known a method of breaking a magnetic floc using a shearing force, and a technique of separating a filter aid containing a magnetic substance by changing a magnetic field by moving a magnet in a separation device.

Japanese Patent No. 5422516 Japanese Patent No. 5389196 Japanese Patent No. 5284242

  The problem to be solved by the present invention is to purify the water to be treated using magnetic particles in water treatment for removing the material to be removed from the water to be treated, and to efficiently use the magnetic particles from the material to be removed. It is to provide a water treatment system and a water treatment method that are well separated and reusable.

  The water treatment system of this embodiment is a water treatment system for removing a solid removal target substance contained in water to be treated, wherein the water to be treated and magnetic particles are mixed, and the removal target substance and the magnetic particles are mixed. Agglomerate forming means for forming an agglomerate containing the agglomerate, agglomerate separation means for separating the agglomerates from the treated water and obtaining purified treated water, and a centrifugal force acting on the separated agglomerates. Crushing means for crushing the agglomerates, separation / recovery means for separating and recovering the magnetic particles obtained by the crushing using magnetic force, and magnetic particles recovered by the separation / recovery means And a recycle means for reusing for forming the aggregate.

  The water treatment method of this embodiment is a water treatment method for removing a solid removal target substance contained in water to be treated, wherein the water to be treated and magnetic particles are mixed, and the removal target substance and the magnetic particles are mixed. Agglomerate forming step for forming an agglomerate containing, an agglomerate separation step for separating the agglomerate from the treated water to obtain purified treated water, and a centrifugal force acting on the separated agglomerate A crushing step for crushing the aggregate, a separation / recovery step for separating and recovering the magnetic particles obtained by the crushing using magnetic force, and a magnetic particle recovered by the separation / recovery step And a reuse step of reusing it to form the agglomerates.

It is the figure which showed schematic structure of the water treatment system which concerns on 1st Embodiment. It is the figure which showed schematic structure of the water treatment system which concerns on 2nd Embodiment. It is the figure which showed schematic structure of the water treatment system which concerns on 3rd Embodiment. It is the figure which showed schematic structure of the water treatment system which concerns on 4th Embodiment. It is the figure which showed schematic structure of the system which provided the turbidity sensor and the particle size meter in the water treatment system which concerns on 4th Embodiment. 6 is a flowchart showing a method of adjusting the amount of flocculant added in the water treatment system of FIG. 5. It is the sectional side view which showed schematic structure of the hydrocyclone. It is AA sectional drawing of the hydrocyclone of FIG. 7A.

Hereinafter, embodiments of the present invention will be described in detail.
As described above, the water treatment system in the present embodiment is a water treatment system that removes a solid removal target substance contained in the water to be treated. The water to be treated and magnetic particles are mixed, and the removal target substance and the magnetic substance are mixed. An aggregate forming means for forming an aggregate containing particles, an aggregate separating means for separating the aggregate from the water to be treated to obtain purified treated water, and centrifugal force is applied to the separated aggregate to cause the aggregation The crushing means for crushing the aggregate, the magnetic particles obtained by crushing are separated and collected using magnetic force, and the magnetic particles collected by the separation and collection means are separated into the aggregates. And a reusing means for reusing for forming.

  Here, the water treatment in the present embodiment is roughly divided into two according to the method of forming an aggregate containing magnetic particles and a substance to be removed. That is, the first separation method by solid-liquid separation obtained by separating the aggregates from the filter surface while forming the aggregates by filtration operation using the magnetic particles as a filter aid, and the magnetic particles and the aggregates There is a second separation method by magnetic separation obtained by forming aggregates as magnetic flocs using an agent and collecting the aggregates by magnetic force.

  Note that the solid removal target substance in the present embodiment is a suspended substance (SS) contained in the water to be treated. The suspended matter is generally a particulate matter having a diameter of 2 mm or less, and is suspended or suspended in water and does not settle naturally due to gravity, so that separation from water is difficult. Examples of the suspended substance (SS) include aquatic, serinite, and other organic substances such as microorganisms, alumina, iron hydroxide, copper hydroxide, and the like.

  Then, the aggregate obtained as described above is crushed into magnetic particles and a substance to be removed by applying centrifugal force, and the crushed magnetic particles are recovered by a magnetic force. Magnetic particles can be reused to form aggregates.

  Hereinafter, the water treatment system and the water treatment method using the separation method will be described in more detail with reference to the drawings.

(First embodiment)
The water treatment system according to the first embodiment uses the first separation method by solid-liquid separation obtained by separating the aggregates from the filter surface, and FIG. 1 is a diagram showing a schematic configuration thereof. is there.

<Water treatment system>
A water treatment system 10 shown in FIG. 1 is a filtration aid for storing a treated water storage tank 11 for storing treated water containing suspended solids that are substances to be removed, and a filter aid containing magnetic substances. A filtration device 13 that forms aggregates from the material storage tank 12, the filter aid and the substance to be removed, captures the aggregates on the filter surface 13a, and obtains purified water by solid-liquid separation; A washing water storage tank 14 for storing washing water for washing away the aggregates from the surface 13a, a centrifugal separator 15 for crushing the aggregates by applying centrifugal force to the washed aggregates, and obtained by crushing. A separation / recovery tank 16 having a magnet 16a for storing the crushed material mixture containing the crushed material and separating and collecting the crushed magnetic particles by magnetic force.

  The water treatment system 10 is configured to be circulated from the filtration device 13 to the filtration device 13 via the washing water storage tank 14 and the centrifuge 15. Further, the magnetic particles separated in the separation / recovery tank 16 are sent to the filter aid storage tank 12, which is also circulated and can be reused as a filter aid.

  Here, the treated water storage tank 11 is supplied with the treated water W1 containing the removal target substance that is the treatment target and temporarily stores the treated water in the filtration device 13 at a desired timing by the pump 17. The liquid can be sent.

  The container shape, capacity, material, etc. of the treated water storage tank 11 are not particularly limited as long as the treated water can be stably stored, but it is preferable that the treated water storage tank 11 has a capacity that can at least obtain a residence time of about 15 minutes. In addition, it is preferable to prevent the treated water from being short-cut by providing a baffle plate in the treated water storage tank 11.

  Here, the water to be treated can be applied as long as it contains a floating substance that is a substance to be removed in the present embodiment. As this treated water, in general, in general industries such as electronic parts manufacturing industry, machining industry, food processing industry, industrial wastewater generated by water washing process in product manufacturing process, abrasive wastewater, cutting wastewater, plating Examples thereof include metal-containing wastewater in which a metal is deposited under conditions such as drainage.

  The filter aid storage tank 12 temporarily stores magnetic particles that are filter aids, and when used, supplies the filter aid to a filter surface 13a of a filter device 13 to be described later, and filters the surface of the filter surface 13a. Used to deposit the agent to form the precoat layer. Here, what is necessary is just to store in the filter aid storage tank 12 as a liquid mixture with a pure water etc. so that a magnetic particle can be supplied to the filtration apparatus 13. FIG. The liquid mixture containing the filter aid can be sent to the filtration device 13 by the pump 18.

  In the water treatment system 10 of FIG. 1, a check valve is provided in the supply pipe for supplying the treated water from the treated water storage tank 11 to the filtration device 13 when the liquid is sent from the filter aid storage tank 12 to the filtration device 13. The water to be treated or the filter aid can be supplied to the filtration device 13 through the same pipe, but an original filter aid supply pipe may be provided separately from the pipe to be treated water.

  Here, the magnetic particles as the filter aid may be magnetic particles that can form an aggregate with the substance to be removed by filtration, and are particularly limited as long as the particles contain a magnetic material. Is not to be done. Examples of the magnetic material include iron, iron-containing alloys, magnetite, titanite, pyrrhotite, magnesia ferrite, manganese magnesium ferrite, manganese zinc ferrite, cobalt ferrite, nickel ferrite, nickel zinc ferrite, barium ferrite, copper zinc ferrite. Etc. By constituting the filter aid from these magnetic particles, the filter aid described below can be easily regenerated by using magnetic force.

Of the above-described particles, magnetic particles containing a ferrite compound having excellent stability in water are more preferable. For example, magnetite (Fe ₃ O ₄ ), which is a magnetite, is preferable because it is not only inexpensive, but also stable as a magnetic substance in water and safe as an element, so that it can be easily used for water treatment.

  In this case, the above-described particles can take various shapes such as a spherical shape, a polyhedron, and an irregular shape, but are not particularly limited. Further, a desirable particle size and shape may be appropriately selected in consideration of manufacturing costs.

  The optimum range of the size of the filter aid varies depending on the magnetic force of the processing equipment, the flow velocity, the capturing method, the density of the magnetic particles, and various conditions. However, the average particle diameter of the magnetic particles in the present embodiment is generally 0.1 to 100 μm, preferably 0.3 to 50 μm. If the lower limit value of the magnetic particles is smaller than 0.1 μm, the magnetic particles can be densely aggregated to remove fine suspended solids (SS) in water, but there is a case where it is not possible to obtain a practical amount of water flow. is there. When the upper limit value of the magnetic particles is larger than 100 μm, the distance between the particles increases, and the suspended matter (SS) in water to be removed may not be sufficiently removed.

The average particle diameter of the magnetic particles can be measured by a laser diffraction method. Specifically, it may be measured by a SALD-3100 type measuring device (trade name) manufactured by Shimadzu Corporation. In the present specification, the term “average particle diameter” means a volume-based 50% integrated value (D ₅₀ ) in the particle size distribution measured by the laser diffraction method as described above, unless otherwise described. Is.

  Furthermore, it is not necessary for all of the filter aids to be made of a magnetic material. That is, even when the magnetic particles as a filter aid contain a magnetic material in part, as long as magnetic separation can be performed in the separation and recovery step described later by applying a magnetic force to these magnetic particles, styrene resin, water The styrene resin, the butadiene resin, the isoprene resin, the acrylonitrile resin, the cycloolefin resin, the phenol resin, the alkyl methacrylate resin, the fluorine resin, or the like bonded or surface-coated may be used. Further, the surface of the magnetic particles may be modified with an alkoxysilane compound such as methyltrimethoxysilane, methyltriethoxysilane, phenyltrimethoxysilane, or phenyltriethoxysilane.

  By using the surface-treated magnetic particles as a filter aid, when the precoat layer to be described later is formed using the filter aid, the precoat layer can be formed to have appropriate voids. Therefore, suspended solids in water can be sufficiently captured and removed, and a sufficient amount of water can be secured.

  The filtration device 13 is a filtration device having a filtration surface 13a. A precoat layer made of magnetic particles is previously formed on the filter surface 13a. When water to be treated containing the removal target substance is supplied to the filter surface 13a on which the precoat layer is formed, the removal target substance is captured by the precoat layer on the filter surface 13a, and the magnetic particles, the removal target substance, and Aggregates containing are formed. And simultaneously with forming an aggregate in this way, a removal target substance is removed from to-be-processed water as an aggregate, and the purified treated water W2 is obtained. This treated water W2 can be used for various purposes as purified water. That is, in the present embodiment, the filtration device 13 has two functions of an aggregate forming unit and an aggregate separating unit.

  The treated water W2 obtained here can be used as water for forming a cleaning liquid or slurry in the water treatment system 10, although not shown. For example, a pipe for supplying a part of the obtained treated water W2 to a cleaning liquid storage tank 14 described later can be provided and used as cleaning water. In addition, a pipe for supplying a part of the treated water W2 obtained to the magnetic particle storage tank 12 and a separation / recovery tank 16 described later is provided, and the magnetic particles and the recovered magnetic particles are mixed in each storage tank. The slurry can be made into a slurry and transferred in the piping so that the processing can proceed smoothly.

  In addition, installing the filtration surface 13a of the filtration device 13 so as to be horizontal can make the precoat layer composed of the filtration aid formed on the surface of the filtration surface 13a a uniform layer, and provide a stable amount of water and water quality. It is preferable in that it can be obtained.

  The washing water storage tank 14 is a tank that stores washing water supplied to separate and remove the aggregate after filtration in the filtration device 13 from the filter surface 13a. The washing water stored here can be supplied to the filtration device 13 via the centrifugal separator 15 described later by the pump 19, and this washing water is a layered aggregate formed on the filtration surface 13 a of the filtration device 13. It peels and removes from the filter surface 13a. It is preferable that the cleaning water supplied to the filtration device 13 can be supplied at an angle close to the horizontal with respect to the filter surface 13a so that the separation by the cleaning water can be effectively performed.

  In addition, the washing water storage tank 14 may temporarily store the aggregate after the aggregate is separated from the filter surface 13a by washing and before the aggregate mixed liquid containing the aggregate is crushed. At this time, the aggregate mixed liquid can be temporarily stored and supplied to the centrifuge 15 described later at a desired timing.

  The centrifuge 15 causes a centrifugal force to act on the aggregate in the aggregate mixture obtained by washing the filtration device 13 so that the aggregate is crushed into magnetic particles and a substance to be removed. . Here, a known centrifuge can be used as the centrifuge 15, but the aggregate can be efficiently crushed, the structure of the apparatus is simple, and the crushed aggregate is easily subjected to the next step. Therefore, it is preferable that the liquid cyclone is used. 7A and 7B, the schematic configuration of the liquid cyclone is shown. When a liquid is introduced from the liquid introduction pipe 153 provided in the tangential direction of the liquid cyclone, a slurry containing a large amount of solids discharged from the bottom nozzle 154, Although it is divided into slurry with a small solid content discharged from the top nozzle 155, by mixing this again, centrifugal force can be applied without solid-liquid separation, and a mixed liquid in which aggregates are crushed is obtained. Can do.

  The liquid mixture containing the crushed material from which the aggregates have been crushed is fed to the separation / recovery tank 16 described below via the treated water side of the filtration device 13 through the same pipe as the cleaning liquid. Whether the liquid is transferred from the filtration device 13 to the cleaning liquid storage tank 14 or the separation / recovery tank 16 is provided with a three-way valve on the discharge side of the cleaning water, and can be switched at a desired timing. In FIG. 1, the pulverized product mixture is sent to the separation / recovery tank 16 via the filtration device 13, but may be sent directly from the centrifuge 15 to the separation / recovery tank 16.

  Next, the separation / recovery tank 16 accommodates the magnetic substance particles and the pulverized substance mixture liquid crushed into the material to be removed by the centrifugal separator 15 and collects the magnetic substance particles from the pulverized substance mixture liquid by magnetic force. is there. In order to recover the magnetic particles, a magnet 16a is provided in the separation / recovery tank 16 along the stirrer and the side surface.

  The magnet 16a may be any magnet that can separate and recover the magnetic particles from the liquid mixture by magnetic force, and examples thereof include an electromagnet and a permanent magnet that moves with an air cylinder. Permanent magnets that move with an air cylinder can be separated by preparing a permanent magnet with a sheath tube and generating / releasing the magnetic field on the sheath tube surface by moving the permanent magnet up and down with an air cylinder or the like. Is.

  The magnetic particles collected by the separation / recovery tank 16 are provided with a circulation path that can be sent to the filter aid storage tank 12 and reused. At this time, before reuse, a cleaning means for cleaning the magnetic particles may be provided before feeding the filter aid storage tank 12.

<Water treatment method>
Next, a water treatment method using the water treatment system 10 of FIG. 1 will be described.
First, a slurry of filter aid and water is prepared in the filter aid storage tank 12. In addition, in order to prepare a slurry-form filter aid, it is performed using the stirrer arrange | positioned in the filter aid tank 12 suitably.

  Next, the filter aid is supplied from the filter aid tank 12 to the filter surface 13a of the filtration device 13 by the pump 18, and a precoat layer composed of the filter aid is formed on the filter surface 13a. The filter surface is generally a filter, and for example, a filter cloth or the like can be used.

  In addition, in order to form a precoat layer, the opening of the filter surface 13a is set to such a size that the filter aid does not penetrate the filter surface 13a. Further, the thickness of the precoat layer is not particularly limited as long as the suspended solids in the water to be treated are captured and removed, and further depends on the size and porosity of the filter aid, for example, 0.1 mm to It can be 10 mm.

  Next, water to be treated containing suspended matter (SS), which is a substance to be removed, is introduced into the water tank 11 to be treated. Then, after stirring with a stirrer as necessary, the suspended matter in the water to be treated is uniformly dispersed, and then the water to be treated is supplied to the filtration device 13 by the pump 17. At this time, since the precoat layer is formed in advance as described above, the water to be treated is actually supplied to the precoat layer formed on the filter surface 13a.

  At this time, suspended substances contained in the water to be treated are captured and removed by the filter aid constituting the precoat layer. The water that has passed through the precoat layer and the filter surface 13a of the filtration device 13 is discharged as treated water W2 from the treated water side pipe of the filtration device 13 to the outside.

  When the filtration device 13 continues the filtration operation and is used for a predetermined time, the trapped amount of suspended matter in the water to be treated in the filtration aid constituting the precoat layer increases, and the suspended matter causes clogging. The flow rate decreases. Therefore, washing is performed before the filtration flow rate decreases in this way. This washing may be controlled to be performed at a predetermined timing by monitoring the filtration time, the water flow pressure, the water flow rate, the filtration flow rate, and the like. For example, when controlling by the filtration flow rate, it may be performed when the filtration flow rate passing through the precoat layer and the filtration surface 13a is 2 m / h or less.

  In this washing operation, the washing water is supplied from the washing water storage tank 14 to the treated water side of the filtration device 13 via the washing water supply line, and the filter aid and the removal target substance constituting a part or all of the precoat layer. The aggregate is separated and returned to the washing water storage tank 14 again as an aggregate mixed solution, and the aggregate mixed solution is further circulated from the washing water supply line to the filtration device 13 via the centrifuge 15.

  At this time, when the aggregate mixed solution passes through the centrifuge 15, a strong shearing force acts on the aggregates contained in the aggregate mixed solution, and the magnetic particles constituting the aggregate and suspended substances are separated. Crush. In this way, by introducing the centrifuge 15 into the washing water supply line, for example, when the filter surface 13a is washed by a nozzle (not shown), a nozzle caused by mixing coarse aggregates. The cleaning operation can be performed without causing clogging of the tip.

  When the above washing operation is finished, the three-way valve is switched so that the washing liquid containing the crushed aggregates (the crushed mixture liquid) flows from the filtration device 13 to the separation and collection tank 16 side. Housed inside.

  In the separation / recovery tank 16, magnetic particles are separated and recovered from the pulverized product mixture using a magnet 16 a (an electromagnet or a permanent magnet that is moved by an air cylinder), and concentrated water containing a substance to be removed at a high concentration is discharged. At this time, since the magnetic particles and the material to be removed are separated in advance by the centrifuge 15, the magnetic particles can be collected smoothly. Thereafter, the magnetic field of the magnet 16 is released to separate the magnetic particles, and a slurry is prepared using pure water or the like prepared in part or other of the treated water W2, and then the magnetic particles are stored in the filter aid storage tank 12. To liquid (circulate). This slurry solution is supplied again from the filter aid storage tank 12 to the filtration device 13 and reused for forming the precoat layer.

  And after forming a precoat layer, as mentioned above, formation of an aggregate by supplying water to be treated on the precoat layer (capturing and removing suspended solids), washing of the aggregate, crushing of the aggregate and Separation and collection of filter aids. By repeatedly performing this operation, it is possible to obtain purified treated water by continuously and efficiently removing suspended substances in the treated water.

(Second Embodiment)
The water treatment system according to the second embodiment uses the first separation method by solid-liquid separation obtained by separating the aggregates from the filter surface, and FIG. 2 is a diagram showing the schematic configuration thereof. is there.

  A water treatment system 20 shown in FIG. 2 is a filtration aid for storing a treated water storage tank 11 for storing treated water containing floating substances that are substances to be removed, and a filter aid containing magnetic substances. A filtration device 13 that forms aggregates from the material storage tank 12, the filter aid and the substance to be removed, captures the aggregates on the filter surface 13a, and obtains purified water by solid-liquid separation; A washing water storage tank 14 for storing washing water for washing away the aggregates from the surface 13a, a centrifugal separator 15 for crushing the aggregates by applying centrifugal force to the washed aggregates, and obtained by crushing. A separation / recovery tank 16 having a magnet 16a for storing the crushed material mixture containing the crushed material and separating and collecting the crushed magnetic particles by magnetic force.

  Since the overall configuration of the water treatment device 20 is similar to that shown in FIG. 1 in the first embodiment, the description of the same components as those in the first embodiment is omitted, and in the following, Differences will be mainly described. Further, the same reference numerals are used for components similar or identical to the components shown in FIG.

  In this embodiment, the elements constituting the water treatment system are substantially the same as those in the first embodiment as described above. The difference is that a pipe is provided and configured so that the filter aid is supplied from the filter aid storage tank 12 to the treated water storage tank 11 by the pump 21 instead of the filtration device 13.

  With such a system configuration, in the water treatment method of the present embodiment, a magnetic substance that is supplied from the filter aid storage tank 12 of the water treatment system 20 to the treated water storage tank 11 via the pump 21 and is a filter aid. The removal target substance contained in the particles and the water to be treated is mixed in the water tank 11 to be treated, and this mixed solution is supplied to the filtration device 13 by the pump 17 and filtered on the filter surface 13a. Such a filtration method is called a body feed method, and is effective when the concentration of suspended solids (SS) in the water to be treated is high. By supplying the filter aid directly to the water to be treated, mixing it, and supplying it to the filtration surface, the cake resistance due to clogging of the cake can be reduced, the amount of filtration can be increased, and the filtration time can be increased. Become.

  As described above, the magnetic particles and the removal target substance filtered by the filtration device 13 form aggregates on the filter surface 13a as in the first embodiment, and purified treated water W2 is obtained. The subsequent processing is the same as in the first embodiment. The aggregate is peeled off and washed from the filter surface 13a with the wash water supplied from the wash water storage tank 14, and is crushed by the centrifuge 15 and then separated. It accommodates in the collection tank 16, and collect | recovers magnetic body particles with the magnet 16a. The recovered magnetic particles are made into a slurry, sent to the filter aid storage tank 12, supplied again to the treated water storage tank 11 as a filter aid, and reused.

  In the first embodiment, the agglomerates are obtained by solid-liquid separation by the pre-coating method and in the second embodiment by the body feed method. However, solid-liquid separation treatment can also be performed using these in combination. .

(Third embodiment)
The water treatment system according to the third embodiment uses the first separation method by solid-liquid separation obtained by separating the aggregates from the filter surface, and FIG. 3 is a diagram showing the schematic configuration thereof. is there.

  The water treatment system 30 shown in FIG. 3 is a filtration aid for storing the to-be-processed water storage tank 11 for storing the to-be-processed water containing the floating substance which is a removal target substance, and the filter aid containing a magnetic body. A filtration device 13 that forms aggregates from the material storage tank 12, the filter aid and the substance to be removed, captures the aggregates on the filter surface 13a, and obtains purified water by solid-liquid separation; A washing water storage tank 14 for storing washing water for washing away the aggregates from the surface 13a, a centrifugal separator 15 for crushing the aggregates by applying centrifugal force to the washed aggregates, and obtained by crushing. A separation / recovery tank 16 having a magnet 16a for storing the crushed material mixture containing the crushed material and separating and collecting the crushed magnetic particles by magnetic force.

  Since the overall configuration of the water treatment device 30 is similar to that shown in FIG. 1 in the first embodiment, the description of the same components as those in the first embodiment is omitted, and in the following, Differences will be mainly described. Further, the same reference numerals are used for components similar or identical to the components shown in FIG.

  In this embodiment, the elements constituting the water treatment system are the same as those in the first embodiment as described above. As a configuration different from the first embodiment, the centrifugal separator 15 is discharged from the separation / recovery tank 16 instead of the circulation line of the filtration device 13 and the washing water storage tank 14, and returned to the separation / recovery tank 16 again by the pump 31. There is a point arranged in the circulation line. This circulation line may be configured so that a liquid discharge line accommodated in the separation / recovery tank 16 is provided with a three-way valve and can be switched between a pipe that is discharged as it is and a pipe that is returned to the separation / recovery tank 16. . In addition, since the arrangement | positioning position of the centrifuge 15 was changed as mentioned above, in the water treatment system 30, the piping by which the washing water containing the aggregate from the filtration apparatus 13 is sent to the washing water storage tank 14 is provided. Absent.

  By adopting such a system configuration, in the water treatment method in the present embodiment, the aggregates are peeled off and washed from the filter surface 13a by the wash water supplied from the wash water storage tank 14 as in the first embodiment. A slurry containing the aggregate (aggregate mixed solution) is obtained, and this aggregate mixed solution is fed to the separation and recovery tank 16 and stored therein.

  The aggregate mixed liquid accommodated in the separation / recovery tank 16 is sent to a circulation line that is returned again to the separation / recovery tank 16 by the pump 31. At this time, when the aggregate mixed solution passes through the centrifugal separator 15 provided in the circulation line, a strong shearing force can be applied to the aggregate contained in the mixed solution. It breaks down into the magnetic particles and the material to be removed.

  When the apparatus configuration as in this embodiment is used, it is possible to simultaneously perform a purification process by filtration using a new filter aid while performing a separation and recovery operation of magnetic particles that are filter aids used in the filtration operation. it can. Therefore, the filtration time can be secured without being affected by the separation and recovery of the filter aid in the water treatment system, and an efficient filtration operation can be performed. In particular, in the suspended matter (SS) that is difficult to remove, filtration often takes time, so the embodiment of this embodiment is preferable.

  In this embodiment as well, solid-liquid separation by filtration may be performed by the body feed method or by the combined use of the precoat method and the body feed method.

(Fourth embodiment)
The water treatment system according to the fourth embodiment uses a second separation method by magnetic separation obtained by collecting aggregates by magnetic force, and FIG. 4 is a diagram showing a schematic configuration thereof.

<Water treatment system>
A water treatment system 40 shown in FIG. 4 is a floc forming tank for mixing water to be treated containing suspended solids that are substances to be removed, magnetic particles, and a flocculant to form magnetic flocs (aggregates). 41, a magnetic particle storage tank 42 for storing magnetic particles containing a magnetic substance, a flocculant addition means 43 for adding a flocculant to the flock formation tank 41, and a flock formation tank 41. A floc separation tank 44 having a magnet 44a for accommodating the floc and magnetically separating the floc by magnetic force, a washing water storage tank 14 for storing washing water for washing off the floc separated in the flock separation tank 44, and flushed. The centrifuge 15 for crushing the floc by applying centrifugal force to the floc and the crushed material mixture containing the crushed material obtained by crushing are stored, and the crushed magnetic particles The composed have separated by magnetic force, and separating and recovering tank 16 having a magnet 16a for collecting the.

  This water treatment system 40 is different from the second embodiment in that the magnetic particles are fed from the magnetic particle storage tank 42 to the flock formation tank 41 to which the water to be treated W1 is supplied by the centrifugal separator 15. The third embodiment is substantially the same as the third embodiment in that it is disposed in a circulation line that is discharged from the separation / recovery tank 16 and returned to the separation / recovery tank 16 again by the pump 31. Further, the magnetic particles separated in the washing water storage tank 14 and the separation / recovery tank 16 for storing the washing water for washing the aggregates are sent to the magnetic particle storage tank 42, which is also circulated to form the magnetic particles. The point that it can be reused as is substantially the same configuration as the first to third embodiments.

  On the other hand, in the present embodiment, the first to third embodiments are different in that the aggregate is obtained by forming a floc by using a flocculant, and that the aggregate is separated by magnetic separation. Each is different. Therefore, the floc forming tank 41, the flocculant adding means 43, and the floc separating tank 44 for magnetically separating the flocs, which are involved in the formation of flocs, are characteristic structures.

  In addition, after forming an aggregate containing magnetic particles and a substance to be removed and purifying the water, the aggregate is crushed, and the magnetic particles are separated, recovered, and reusable. The general idea is the same in all the embodiments described above.

  As described above, the overall configuration of the water treatment device 40 is similar to that shown in FIGS. 1 to 3 in the first to third embodiments, so the description of the same or similar components is omitted. In the following, the difference will be mainly described. Also, the same reference numerals are used for the same or similar components as those shown in FIGS.

  First, the floc forming tank 41 contains the water to be treated W1 to be supplied, and further supplies the magnetic particles and the flocculant and mixes them, thereby including the floc containing the substance to be removed and the magnetic particles. This is a place where (aggregate) is formed. The magnetic particles are supplied from the magnetic particle storage tank 42 by the pump 21. Further, the flocculant only needs to be added to the water to be treated at the same time as the magnetic particles, and even if it is directly charged into the floc forming tank 41, it is stored in the tank as a solution containing the flocculant like the magnetic particles. Alternatively, the floc forming tank 41 may be charged at a predetermined amount and timing.

  The flocculant addition means 43 accommodates the flocculant and adds a predetermined amount of the flocculant to the flock formation tank 41 at a predetermined timing. The amount of flocculant added and the timing of the addition are excellent in the purification efficiency of the water to be treated according to the concentration of the substance to be removed contained in the water to be treated W1, the strength of the floc formed, the turbidity of the water to be treated, etc. What is necessary is just to determine suitably so that.

  The flock separation tank 44 is for receiving the water to be treated containing the flock formed in the flock forming tank 41 by the pump 17 and storing the water to be treated. The floc separation tank 44 is provided with a magnet 44a so that flocs in the water to be treated can be magnetically separated. Here, the magnet 44a can be the same as the magnet 16a described in the first embodiment.

  Further, this floc separation tank 44 has three pipes on its discharge side that can be switched between a line for obtaining purified treated water W2 and a line for feeding the separated floc to the recovery separation tank 16 by washing. A valve is provided.

  Other constituent elements have the same functions and operations as those of the first to third embodiments except that the aggregate is a floc.

  For example, the magnetic particle storage tank 42 accommodates magnetic particles and can be supplied to the flock formation tank 41 by the pump 21 at a predetermined timing. This is the filter aid storage tank 12 in the second embodiment. This is the same as the aspect in which the filter aid is supplied to the treated water storage tank 11.

  The washing water storage tank 14 stores washing water and supplies it to the floc separation tank 44 by the pump 19 so that the magnetically separated floc can be washed away. The flush-containing washing water washed away is sent to the separation and recovery tank 16 by a three-way valve.

  The separation / recovery tank 16 accommodates the fed floc-containing washing water, is once discharged from the separation / recovery tank 16, and is circulated back to the separation / recovery tank 16 by the pump 31 and returned. In this circulation line, a centrifuge 15 is provided, and the clot 15 crushes the floc into magnetic particles and other components (substance to be removed and flocculant). The pulverized magnetic particles are separated and collected by the magnet 16a, and the magnetic particles obtained thereby are returned to the magnetic particle storage tank 42 so that the magnetic particles can be circulated and reused. In the separation / recovery tank 16, only the aggregates are changed to the floc of this embodiment, and the others are the same as those of the third embodiment.

<Water treatment method>
Hereinafter, the water treatment method of this embodiment will be described with respect to characteristic portions different from those of the other embodiments.

  First, the water to be treated W1 is supplied to and stored in the flock formation tank 41, and the magnetic particles are added from the magnetic particle storage tank 42 and the flocculant is added from the flocculant addition means 43 to the water to be treated. . When these are mixed and agitated, a floc having magnetism is formed in which suspended substances (SS), which are substances to be removed in the water to be treated, and magnetic particles are aggregated by an aggregating agent.

  The formed magnetic floc is sent from the floc forming tank 41 to the floc separating tank 44 by the pump 17. A magnet 44a is provided inside the floc separation tank 44, and the floc in the for-treatment water accommodated in the flock separation tank 44 is separated and removed by the magnet 44a to obtain purified treated water W2.

  Thereafter, the cleaning water is supplied from the cleaning water storage tank 14 and the magnetic field of the magnet 44a is released, so that the floc is concentrated and contained (floc mixed liquid). The three-way valve is switched, and this slurry is separated and recovered. Liquid is supplied to and stored in the tank 16.

  The floc mixture contained in the separation / recovery tank 16 is sent to a circulation line that is returned to the separation / recovery tank 16 by the pump 31 again. At this time, when the floc liquid mixture passes through the centrifugal separator 15 provided in the circulation line, a strong shearing force can be applied to the floc contained in the liquid mixture, and the floc is a component of the floc. Crush into certain magnetic particles and other components (substance to be removed and flocculant).

  The slurry containing the crushed material (crushed material mixture) crushed as described above separates and collects the magnetic particles from the crushed material mixture using the magnet 16a (permanent magnet moved by an electromagnet or an air cylinder). The concentrated water containing the substance to be removed at a high concentration is discharged. At this time, since the magnetic particles and the material to be removed are separated in advance by the centrifuge 15, the magnetic particles can be collected smoothly. Thereafter, the magnetic field of the magnet 16 is released to separate the magnetic particles, and a slurry is formed using a part of the treated water W2 or other pure water prepared, and then the magnetic particles are stored in the magnetic particle storage tank 42. To liquid (circulate). This slurry solution is supplied again from the magnetic particle storage tank 42 to the flock formation tank 41, and is reused for the formation of magnetic floc.

  The magnetic particles used in this embodiment can be incorporated into the floc when the floc is formed by the substance to be removed and the flocculant to form a floc together with the above components. If it has, it will not specifically limit. As this magnetic particle, the same magnetic particle as the filter aid used in the first to third embodiments can be used. In addition, although the magnetic body may be a filter aid containing the magnetic body used in the first to third for floc formation, the average particle diameter of the magnetic body particles in this embodiment is preferably 0.1 to 100 μm. It is a range. If the lower limit value of the magnetic particles is smaller than 0.1 μm, the magnet 16 may increase the collection time and deteriorate the processing efficiency. When the upper limit value of the magnetic particles is larger than 100 μm, the sedimentation speed of the magnetic particles is too high, and there is a possibility that a floc containing a uniform magnetic material cannot be formed in the flock formation tank 41.

  In this embodiment, an aggregating agent is added to the water to be treated in addition to the magnetic particles so that the substance to be removed and the magnetic particles in the water are aggregated to form a magnetic floc. Examples of the flocculant used at this time include known flocculants. Examples of the flocculant include an inorganic flocculant and an organic flocculant. Examples of the inorganic flocculant include polyaluminum chloride, ferric sulfate, ferric chloride, and aluminum sulfate. The organic flocculant is classified into an anionic polymer, a cationic polymer, and a nonionic polymer, and examples thereof include polyacrylamide, polyacrylic acid ester, polyamidine, polyamine, and polyacrylamide.

  In this embodiment, the flocculant is subjected to water purification treatment by determining the amount and timing of addition of the flocculant based on the quality of the water to be treated W1, the strength of the obtained floc, the turbidity of the treated water, and the like. However, the amount of the flocculant added may be controlled while monitoring the quality of the treated water W2 obtained by the purification treatment, the particle size of the separated floc, and the like.

  In order to control the addition amount of the flocculant as described above, for example, as shown in FIG. 5, a turbidity sensor 51 capable of measuring the turbidity of the treated water W2 obtained from the floc separation tank 44, and a separation / recovery tank 16 can be carried out by providing a particle size meter 52 in the preceding stage of the centrifugal separator 15 in the circulation line provided in FIG. Here, FIG. 5 is a water treatment system in which a turbidity sensor 51 and a particle size meter 52 are additionally provided in the water treatment system shown in FIG. 4, and the amount of flocculant added can be controlled according to the measurement results. 1 is a diagram showing a schematic configuration of a system 50. FIG.

  The control of the addition amount of the flocculant can be performed, for example, according to the flowchart shown in FIG. That is, when water treatment is started, first, a set amount of flocculant is added (S1), and purification treatment is performed. At this time, the turbidity of the treated water W2 obtained by the purification treatment is measured by the turbidity sensor 51, and the particle size of the separated floc before crushing is measured by the particle size meter 52, and the water quality is constantly monitored.

  First, the water quality of the treated water W2 is measured by the turbidity sensor 51, and it is determined whether or not the measured turbidity value is equal to or less than a preset specified value (S2). Here, when the turbidity value is equal to or less than the specified value, the floc particle size is measured by the particle size meter 52, and it is determined whether or not the measured particle size value is equal to or less than a preset specified value (S3). .

  When both the turbidity and the particle size are equal to or less than the specified values, it is determined whether or not the water treatment is continued without any problem in the water quality of the treated water W2 and the flock formation state (S4). When the water treatment is continued, the flocculant is added again to the water to be treated W1 at a predetermined timing without changing the amount of flocculant added (S1), and the determinations of S2 to S4 are further repeated. Continue processing.

  Moreover, in the determination of turbidity (S2), when the measured value exceeds the specified value, the water quality of the treated water W2 is deteriorated, and the removal target substance contained in the treated water W1 is not sufficiently removed. Means that. Therefore, in this case, the addition amount of the flocculant is increased so that the substance to be removed in the water to be treated is sufficiently aggregated to form a floc, and the flocculant is added again.

  In the particle size determination (S3), if the measured value exceeds the specified value, it means that coarse particles are present, that is, the flocs formed are too large. In this case, the amount of flocculant added The flocculant is added again so that the floc formed is not too large.

[Conditions for agglomeration]
In the crushing step of the first to fourth embodiments, any magnetic material particles in the aggregate may be used so long as they can be reused, and the centrifugal force acts on the aggregate. As mentioned above, a hydrocyclone is preferred. As shown in FIGS. 7A and 7B, the hydrocyclone has a cylindrical portion 151 provided at the upper portion and an inverted truncated cone portion 152 provided continuously at the lower end of the cylindrical portion. It has a liquid introduction tube 153 for introducing a liquid in a tangential direction when viewed.

  When the aggregate mixed liquid is introduced from the liquid introduction tube 153, centrifugal force acts on the aggregate in the aggregate mixed liquid, and the aggregate is crushed. The crushed agglomerates are arranged on the peripheral wall side as the specific gravity and particle diameter are larger, and on the center side as the specific gravity and particle diameter are smaller. At this time, a downward flow is generated in the peripheral wall along the taper of the cyclone, and the flow having a large specific gravity and particle diameter is led to the bottom nozzle 154, while the central portion is conversely an upward flow. Is generated and is discharged to the top nozzle 155 along this flow. In the present embodiment, the solution discharged from the bottom nozzle 154 and the top nozzle 155 is finally mixed, and the crushed material containing the crushed material in which the aggregate is crushed into the magnetic particles and the substance to be removed. The mixed liquid is returned to the separation / recovery tank 16.

At this time, when the flow rate of the aggregate mixed liquid introduced into the hydrocyclone is V [m / s] and the inner diameter of the cylindrical portion 151 into which the aggregate mixed liquid is introduced is D [m], V × V / D is the following relational expression (1)

100 ≦ V × V / D ≦ 5000 (1)

It is preferable to satisfy. When the above V × V / D is less than 100, the aggregates are not sufficiently crushed and the recovery efficiency of the magnetic particles may be lowered, and the upper limit is not particularly limited, but the physical limit of the device structure Is preferably about 5000. By setting it as such conditions, an aggregate can fully be crushed and it can attach to the following process.

In addition, when a floc having magnetic properties is formed by adding a flocculant as in the fourth embodiment, it is preferable to apply a larger shearing force because the binding force of the formed floc is relatively strong. The following relational expression (2)

1500 ≦ V × V / D ≦ 5000 (2)

It is preferable to treat the aggregate under conditions that satisfy the above conditions. If the above V × V / D is less than 1500, in the water treatment in which the suspended solids are removed using a flocculant, generally formed flocs may not be sufficiently crushed. By satisfy | filling the said conditions, a floc can be crushed to the grade which fully improves collection | recovery efficiency.

  In the case of adding the flocculant, the strength of the floc formed varies depending on the amount of the substance to be removed contained in the water to be treated W1 and the amount of flocculant added, and the amount of flocculant added is obtained. The water quality of the treated water W2 to be treated is also affected, so that the treatment conditions for sufficiently breaking the flocs may be determined as appropriate while balancing these conditions. At this time, the strength of the floc can be measured by, for example, a shear force generated by a bottomed cylinder and a rotating body arranged in the bottomed cylinder as shown in Patent Document 3, and in determining processing conditions It is efficient to refer to the above strength.

  As mentioned above, although several embodiment of this invention was described, these embodiment was posted as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Water treatment apparatus 11 Water to be treated storage tank 12 Filter aid storage tank 13 Filtration apparatus 13a Filter surface 14 Washing water storage tank 15 Disintegration means 16 Separation and recovery tank 16a Magnet 17-19 Pump

Claims (7)

In a water treatment system for removing a solid removal target substance contained in water to be treated,
Aggregate forming means for mixing the water to be treated and magnetic particles to form an aggregate containing the substance to be removed and the magnetic particles;
Aggregate separation means for obtaining treated water separated and purified from the treated water,
A crushing means for crushing the aggregate by applying centrifugal force to the separated aggregate;
Separating and collecting means for separating and collecting the magnetic particles obtained by crushing using magnetic force;
Reusing means for reusing the magnetic particles recovered by the separation and recovery means for forming the aggregates;
A water treatment system comprising:   The water treatment system according to claim 1, wherein the crushing means is a hydrocyclone.   The water treatment system according to claim 2, wherein the liquid cyclone is provided in a circulation line that circulates from the aggregate separation unit or the separation and recovery unit.   The agglomerate forming means comprises a filtration device and a precoat layer in which the magnetic particles are deposited as a filter aid on the filtration surface of the filtration device, and supplies the water to be treated to the precoat layer. The water treatment system according to any one of claims 1 to 3, wherein a collection can be formed.   The agglomerate forming means includes magnetic particle addition means and aggregating agent addition means for adding magnetic particles and an aggregating agent to the water to be treated so that a magnetic floc can be formed. The water treatment system according to any one of claims 1 to 3. The flow rate of the aggregate mixed solution containing the aggregates supplied to the crushing means is V [m / s], and the inner diameter of the container to which the aggregate mixed liquid is supplied in the crushing means is D [m]. V × V / D is expressed by the following relational expression (1)

100 ≦ V × V / D ≦ 5000 (1)

The water treatment system according to any one of claims 1 to 5, wherein: In a water treatment method for removing a solid removal target substance contained in water to be treated,
An agglomerate forming step of mixing the water to be treated and magnetic particles to form an aggregate containing the substance to be removed and the magnetic particles;
An aggregate separation step of obtaining treated water purified by separating the aggregate from the treated water;
A crushing step of crushing the aggregate by applying a centrifugal force to the aggregate;
A separation and recovery step of separating and recovering the magnetic particles obtained by crushing using magnetic force;
A recycling step of reusing the magnetic particles recovered by the separation and recovery step for the formation of the aggregate;
A water treatment method characterized by comprising:

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