JP4656830B2 - Solid-liquid separation method and apparatus - Google Patents

Description

The present invention relates to a solid-liquid separation method and apparatus, and more particularly, the separation material bound to the magnetic powder, for example, to solid-liquid separation method and apparatus for separating sludge from the fluid by the magnetic body (magnet).

  Conventionally, the activated sludge method has been widely used as a treatment method for sewage and organic wastewater. In this method, basically, organic substances contained in sewage etc. are decomposed by activated sludge in a treatment tank such as an aeration tank, and then activated sludge is settled and separated by gravity in the final sedimentation tank, and the activated sludge separated here is treated. The model is to return to the tank. In such an activated sludge method, in recent years, as a means for separating treated water and activated sludge, magnetism is imparted to the activated sludge by adding magnetic powder to the activated sludge, and this activated sludge is used as a permanent magnet. A magnetic separation method and apparatus for magnetic separation and separation from treated water has been proposed (see, for example, Patent Document 1).

In addition, as a means for separating activated sludge, a method and an apparatus for performing a filtration treatment by forming a dynamic filtration layer composed of activated sludge particles on the surface of a dynamic filtration membrane that is a water-permeable filter (for example, patents) are also known. Reference 2).
Japanese Patent Publication No. 63-59759 JP 2001-87635 A

  However, in order to perform sufficient magnetic separation with a normal magnetic separation device, it is necessary to use a magnet made of a strong magnetic material, for example, a special magnet such as a superconducting magnet or an electromagnet, and the device cost is more than necessary. May rise. Also, in the case of dynamic filtration, there is a problem that a predetermined filtration process (solid-liquid separation process) cannot be performed after the dynamic filtration membrane is washed until a sufficient dynamic filtration layer is formed on the surface. there were.

Therefore, the present invention makes it possible to use a permanent magnet that can be obtained at low cost while taking advantage of the advantages of the magnetic separation device and the dynamic filtration device, and to perform a predetermined solid-liquid separation process immediately after washing the filter body. It aims at providing the solid-liquid separation method and apparatus which can be performed reliably.

In order to achieve the above object, the solid-liquid separation method of the present invention uses a solid-liquid separation device in which the inside of a sealed container is partitioned by an aqueous filter and partitioned into an inflow chamber and an outflow chamber. a method of solid-liquid separation, using a magnetic material on at least a portion of the water permeability filtration body, by adding magnetic powder to the sludge suspension, coupling the magnetic powder to sludge sludge suspension It flows into the inflow chamber sludge suspension containing the magnetic powder-containing sludge which is formed by through the inlet pipe, when the sludge suspension through said water permeability filtration body, the sludge suspension wherein the magnetic powder-containing sludge, adsorbed to the magnetic of the water flow filtration body, while forming a dynamic filtration layer on the water permeability filtration body, magnetic powder from the sludge suspension in the dynamic filtration layer Treatment of the outflow chamber that separated the sludge and passed through the dynamic filtration layer It is characterized by flowing a. Further, solid-liquid separator of the present invention is a solid-liquid separator was partitioned internally to the inlet chamber partitioned by a water-permeable filtering material and outflow chamber a sealed container, the magnetic powder sludge suspension was added, it provided the inlet pipe for flowing the sludge suspension containing the magnetic powder-containing sludge which is formed by coupling the magnetic powder to sludge sludge suspension in the inlet chamber, the water permeability filtration body An outflow pipe for allowing the treated water to flow out is provided in the outflow chamber , a magnetic material is used for at least a part of the water-permeable filter body, and the sludge suspension is passed when the sludge suspension passes through the water-permeable filter body. The magnetic powder-containing sludge in the turbid liquid is adsorbed on the magnetic material of the water-permeable filter body, and a dynamic filtration layer is formed on the water-permeable filter material. It is characterized by separating magnetic powder-containing sludge . Further, the inflow chamber and the outflow chamber are partitioned by the water-permeable filter body arranged in the horizontal direction and the partition plate arranged in the vertical direction, or the inflow chamber and the outflow chamber are arranged in the vertical direction. In addition to partitioning by the partition plate, a plurality of filter body modules are provided on the inflow chamber side of the partition plate, and the filter body module is provided with the water-permeable filter body on both surfaces of the support body. It is characterized in that it communicates only with the outflow chamber through the partition plate, and further, a concentrated sludge extraction pipe is provided in the inflow chamber, and a pressurized air introduction pipe and an exhaust pipe are provided in the outflow chamber. Further , instead of the water-permeable filter body using a magnetic material at least in part, a plastic magnet having flexibility on the outer periphery of a pipe-shaped support member arranged in the vertical direction is spirally arranged through a spacer. Wound around Established a water-permeable filtering material inside said container, said inlet chamber at the bottom of the water-permeable filtering material wound in a vortex winding shape, and characterized in that dividing the outflow chamber into upper, also the inlet chamber In addition, a pump for circulating the activated sludge suspension between the tank and the sludge storage tank is provided, and the outflow chamber and the treated water storage tank are connected via a pump different from the pump.

According to the solid-liquid separation method and apparatus of the present invention, the magnetic substance is used as the water-permeable filter, so that the substance to be separated combined with the magnetic powder is adsorbed by the magnetic force on the surface of the filter after washing. Since the filtration layer is formed in a short time, a predetermined solid-liquid separation process can be performed immediately after washing the filter body. In addition, since the substance to be separated is captured by the filter body by magnetic force, the substance to be separated combined with the magnetic powder can be reliably captured by the magnetic force even if the interval between the water-permeable portions is widened, and the substance to be separated leaks. Nor. Further, by widening the interval between the water-permeable portions, the frequency of cleaning can be reduced and the cleaning operation is facilitated.

  FIG. 1 is an explanatory view showing a first embodiment of the solid-liquid separation device of the present invention. This solid-liquid separation device is used by installing it on the liquid surface portion on the downstream side of the biological reaction tank in the wastewater treatment device, and separating the activated sludge by solid-liquid separation of the activated sludge suspension in the biological reaction tank. An example of obtaining water is shown.

  The solid-liquid separator shown in the present embodiment includes an inflow chamber 14, an outflow chamber 15, and an inside of a sealed container (casing) 11 by a filter body 12 disposed in a horizontal direction and a partition plate 13 disposed in a vertical direction. And an inflow pipe 16 for activated sludge suspension is provided in the inflow chamber 14, and an outflow pipe 17 for treated water, an extraction pipe 18 for concentrated sludge, an inlet pipe 19 for pressurized air, and an exhaust pipe 20 are provided in the outflow chamber 15. Is provided.

  Moreover, the said filter body 12 is arrange | positioned in the up-down direction intermediate part of the partition plate 13, and it is made to be able to store treated water on the upper surface of the filter body 12. FIG. Furthermore, if the strainer 21 is provided at the inflow portion of the inflow pipe 16 as necessary, troubles in which coarse impurities flow into the container 11 and damage the filter body 12 can be avoided. . Moreover, although the shape of the container 11 is arbitrary, it can also be made into a pressure vessel shape in consideration of deformation due to pressure and the like.

  The filter body 12 is formed by laminating a plate-like body or a film-like body containing a magnetic body at a predetermined interval or winding it in a spiral shape to form a water passage between adjacent plate-like bodies or between film-like bodies, Various shapes such as a plate-like body provided with a perforated hole such as an oval shape or a long hole or a slit as a water-permeable portion, and a net-like body having an appropriate opening can be used. At this time, the entire filter body 12 may be formed of a magnetic material. For example, a network made of a magnetic material may be supported by a support made of a suitable non-magnetic material having water permeability, It is also possible to use a magnetic material only for the part to be the part. Although the entire filter body 12 can be formed as a single structure, the filter body 12 is divided and formed into magnetic modules having an appropriate size, and several combinations of the magnetic modules are combined to form the filter body 12. Can also be formed.

  That is, the filter body 12 has a gap or a through hole through which an activated sludge suspension containing activated sludge (magnetic powder-containing sludge) combined with magnetic powder can pass between the magnetic poles of the magnetic body constituting the filter body 12. Formed with a magnetic material having a water passage, magnetic powder-containing sludge is magnetically adsorbed in the gaps or through holes of the magnetic material, and deposited on the adsorbed magnetic powder-containing sludge and further on the magnetic powder-containing sludge adsorbed on the magnetic material Any structure and shape can be adopted as long as the dynamic filtration layer can be formed by the magnetic powder-containing sludge and other solid content.

  As the magnetic material, a special magnet such as a superconducting magnet or an electromagnet can be used. However, since the magnetic powder-containing sludge is substantially separated by a dynamic filtration layer, all of the magnetic powder-containing sludge is removed only by magnetic force. Since it is not separated from the suspension, a general and inexpensive permanent magnet such as a ferrite magnet can be used. In addition, when a combination of an electromagnet, a superconducting magnet, or the like and a ferromagnetic matrix is used, the excitation force can be zero at the time of backwashing, so that the backwashing effect can be improved.

  In order to separate activated sludge with this solid-liquid separator, it is necessary to combine magnetic powder with activated sludge in advance to obtain a magnetic powder-containing sludge. As the magnetic powder to be used, an appropriate one can be selected. However, since magnetic powder having a size of 10 μm or more is too heavy for activated sludge, it is often separated from activated sludge by gravity. Smaller ones are preferred, and usually those in the range of 0.05 to 2 μm are optimal. Although it is possible to use ultrafine magnetic powder, it is not preferable because the cost of the magnetic powder increases.

  Further, the coercive force of the magnetic powder is suitably 0 to 200 Oe, and the magnetic powder having an excessively large coercive force has the disadvantage that it aggregates due to its own magnetic force and separates from the activated sludge and settles. Furthermore, in consideration of long-term use, it is preferable to use an oxide-based magnetic powder that hardly dissolves or deteriorates in water at room temperature. 0.1 to 1.0 μm, for example, about 0.4 μm of iron trioxide powder is optimal.

  If the concentration (addition amount) of magnetic powder is too low, a strong magnet (magnetic material) such as a superconducting magnet is required to separate activated sludge. Conversely, if the concentration is too high, the cost of magnetic powder increases. Therefore, it is preferable that the MLVSS of the activated sludge is in a concentration range of 0.01 to 10 with respect to 1, and normally, if the concentration is set to be the same level as the MLVSS of the activated sludge. Good.

  When such magnetic powder is put into the activated sludge suspension at an appropriate position such as a biological reaction tank or circulation system, it immediately becomes adsorbed and held in the activated sludge and contains magnetic powder that is attracted to the magnetic material. It becomes activated sludge. In general waste water treatment equipment, most or all of this magnetic powder-containing activated sludge is circulated together with the returned sludge. Therefore, the addition and mixing of the magnetic powder to the activated sludge suspension usually starts solid-liquid separation. It may be performed only once before, but can be added as appropriate depending on the situation of the water treatment facility. Also, when adding magnetic powder, add an appropriate amount of magnetic powder at appropriate intervals while circulating the activated sludge so that the magnetic powder is evenly adsorbed to the entire activated sludge circulating in the system. Is preferred.

  This solid-liquid separation device alternately repeats solid-liquid separation processing (filtration processing) and washing processing by opening and closing valves 16V, 17V, 18V, 19V, and 20V provided in each pipe in a predetermined order. I can do it. That is, the valve 16V of the inflow pipe 16, the valve 17V of the outflow pipe 17, and the valve 20V of the exhaust pipe 20 are opened, and the valve 18V of the extraction pipe 18 and the valve 19V of the introduction pipe 19 are closed. The activated sludge suspension outside the container 11 can flow into the container due to the difference in water level between the inside and outside, and filtration can be performed. The treated water that has passed through the filter body 12 overflows the upper end of the partition plate 13 and flows out. It flows out of the bioreactor from 17.

  On the other hand, the valves 16V, 17V, and 20V are closed, the valves 18V and 19V are opened, and pressurized air is introduced from the introduction pipe 19 to store the treated water stored above the filter body 12. Can be made to flow downward through the filter body 12 under the pressure of the pressurized air, whereby the dynamic filter layer deposited on the surface of the filter body 12 can be washed away to wash the filter body 12, and the washing waste water (concentrated sludge) After being extracted by the extraction tube 18, it is usually returned to the upstream side of the biological reaction tank.

  This washing operation is performed at a preset time interval by a timer, detected by detecting a rise in the water level in the biological reaction tank, or by detecting the turbidity of the treated water flowing out from this solid-liquid separator. be able to. Thus, by regularly performing the washing operation of the filter body 12, the solid-liquid separation can be continued efficiently in a stable state. Moreover, in order to perform more reliable washing operation, auxiliary means such as air washing can be used in combination.

  When the filtration process is started after the washing operation, the pressurized air in the container 11 is discharged from the exhaust pipe 20 by opening the valves 16V, 17V, and 20V and closing the valves 18V and 19V. The activated sludge suspension flows in and rises through the water passing portion of the filter body 12. At this time, the magnetic powder-containing sludge in the activated sludge suspension is drawn to the magnetic body constituting the filter body 12. Since it is adsorbed on the surface of the filter body 12, sludge hardly leaks into the treated water. In addition, by forcibly depositing the magnetic powder-containing sludge on the surface of the filter body 12 by magnetic force, a dynamic filtration layer can be formed on the surface of the filter body 12 in a short time. It can be demonstrated in a short time.

  In addition, when a sludge is physically trapped to form a dynamic filtration layer, in consideration of leakage of the sludge into the treated water after washing, the water passage portion of the filter body 12 could not be made so large. In this way, by trapping sludge with a magnetic force to form a dynamic filtration layer, the size of the water passing portion can be expanded to 0.05 to several millimeters. It is also possible to use cm. Furthermore, since the filtration process is performed by a dynamic filtration layer, solid-liquid separation can be performed with higher efficiency than conventional magnetic separation devices, and suspended components that are not bonded to magnetic powder can also be separated. Furthermore, since it is basically the same method as general dynamic filtration, it is possible to apply various operations conventionally performed in dynamic filtration, for example, separation of enzymes and RNA by adding zirconium hydroxide. In addition, it is possible to remove dissolved phosphorus with iron oxide, which is a magnetic substance.

  2 and 3 show a second embodiment of the solid-liquid separator of the present invention. FIG. 2 is a sectional plan view, and FIG. 3 is a sectional front view. This solid-liquid separator shows an example in which a plurality of filter bodies are installed in a container so as to cope with a large volume of processing. In the following description, the same components as those in the solid-liquid separator shown in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the solid-liquid separation device shown in this embodiment, a plurality of filter modules 32 are provided on a partition plate 31 that partitions the inside of the container 11 into an inflow side and an outflow side. In the filter module 32, the filter body 12 formed as described above is installed on both surfaces of the support 33, and the inside of the support 33 is communicated only with the outflow chamber 15 via the partition plate 31. In addition, a rectifying plate 34 is provided in the inflow chamber 14 for making the flow of the activated sludge suspension uniform.

  Therefore, the activated sludge suspension flowing into the inflow chamber 14 passes through the filter body 12 on both sides of the support 33 and flows out from the support 33 into the outflow chamber 15. And when passing the filter body 12, the magnetic powder containing sludge in activated sludge suspension is isolate | separated by the dynamic filtration layer of the filter body 12 as mentioned above. Also in this solid-liquid separator, by opening and closing the valve of each pipe connected to the container 11, the filtration treatment and the washing operation can be alternately repeated as described above.

4 and 5 show a third embodiment of the solid-liquid separation device of the present invention. FIG. 4 is a system diagram, and FIG. 5 is a plan view of a filter body. In this solid-liquid separator, a filter body 45 in which a plastic magnet 43 having flexibility is wound around an outer periphery of a pipe-shaped support member 42 in a spiral shape via a spacer 44 is installed inside a cylindrical container 41. A circulation inflow pipe 48 and a circulation outflow pipe 49 are provided at the bottom of the cylindrical container 41 to circulate the activated sludge suspension with the sludge storage tank 47 by the pump 46, and the pump 50 is provided at the top of the cylindrical container 41. The treated water outflow pipe 51 provided is connected to the treated water storage tank 52.

  Part of the activated sludge suspension circulating through the lower part of the cylindrical container 41 and the sludge storage tank 47 by the circulation inflow pipe 48 and the circulation outflow pipe 49 is sucked by the pump 50 of the treated water outflow pipe 51 and is filtered. 45 passes upward, and the magnetic powder-containing sludge is separated by the filter body 45. The treated water after the sludge separation is sent from the treated water outflow pipe 51 to the treated water storage tank 52.

  Since this solid-liquid separation device can adjust the separation performance of the magnetic powder-containing sludge by adjusting the size (thickness) of the spacer 44 and the magnetic force of the plastic magnet 43, an experiment before applying to the actual device. Ideal as a device.

A solid-liquid separator having the structure shown in FIGS. 4 and 5 was prepared. A plastic magnet having a width of 3 cm, a thickness of 2 mm, double-sided multipolar magnetization, and a direct-magnetic pitch of 5 mm was used. The plastic magnet was wound around the outer periphery of a support member (acrylic tube) having an outer diameter of 18 mm through a 1.5 mm spacer until the diameter became 5 cm, and inserted into a cylindrical container made of an acrylic tube having an inner diameter of 5 cm. The effective area as a filter body (including a magnet and a gap (gap) part) is about 18 cm ² .

  In addition, as the raw material sludge, activated sludge collected at a sewage treatment plant was conditioned with synthetic sewage mainly composed of polypeptone and glucose. To this sludge, commercially available iron trioxide as magnetic powder is added so as to have the same concentration as MLVSS, and concentrated to obtain an activated sludge suspension having an MLVSS of about 5000 mg / L and a magnetic powder concentration of about 5000 mg / L. Prepared and used for separation experiments.

  As a result, almost no sludge leakage was observed up to an integrated flow rate of 200 mL, and almost 100% solid-liquid separation could be achieved. Further, the permeation pressure was substantially constant at 0.7 cm at the time of the first 100 mL filtration, 2.4 cm at the time of 200 mL filtration, and 5 to 6 cm after the 500 mL filtration. Furthermore, excess sludge could be washed away by flowing water from the passing liquid side to the filter medium.

  The solid-liquid separation apparatus of the present invention is capable of separating sludge in various wastewater treatment (biological treatment), iron hydroxide and aluminum hydroxide, water sludge separation, methane fermentation tank sludge separation, etc. As long as the substance to be separated in the processing fluid is in a state capable of being combined with the magnetic powder, it can be applied to various uses.

It is explanatory drawing which shows the 1st example of a solid-liquid separator of this invention. It is a cross-sectional top view which shows the 2nd form example of the solid-liquid separator of this invention. It is a sectional front view similarly. It is a systematic diagram which shows the 3rd example of a solid-liquid separator of this invention. It is a top view of a filter body similarly.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Container (casing), 12 ... Filter body, 13 ... Partition plate, 14 ... Inflow chamber, 15 ... Outflow chamber, 16 ... Inflow pipe, 17 ... Outflow pipe, 18 ... Extraction pipe, 19 ... Introduction pipe, 20 ... Exhaust pipe Pipe, 21 ... Strainer, 31 ... Partition plate, 32 ... Filter body module, 33 ... Support, 34 ... Current plate, 41 ... Cylindrical container, 42 ... Support member, 43 ... Plastic magnet, 44 ... Spacer, 45 ... Filtration Body, 46 ... pump, 47 ... sludge storage tank, 48 ... circulation inflow pipe, 49 ... circulation outflow pipe, 50 ... pump, 51 ... treated water outflow pipe, 52 ... treated water storage tank

Claims (7)

In a method for solid-liquid separation of a sludge suspension using a solid-liquid separation device in which the inside of a sealed container is partitioned by a water-permeable filter and divided into an inflow chamber and an outflow chamber, at least one of the water-permeable filters is used. A magnetic substance is used for the part, magnetic powder is added to the sludge suspension, and the sludge suspension containing the magnetic powder-containing sludge formed by combining the magnetic powder with the sludge in the sludge suspension flows in. flows into the inflow chamber through the tube, when the sludge suspension through said water permeability filtration body, the magnetic powder-containing sludge of the sludge suspension, magnetic material the water flow filtration body adsorbed to, the through while forming a dynamic filtration layer to the aqueous filtration body, with the separation of magnetic powder-containing sludge from the sludge suspension in the dynamic filtration layer, outflow chamber having passed through the dynamic filtration layer Solid-liquid separation of sludge suspension characterized by flowing out treated water Law. In solid-liquid separator that partitions the interior of the sealed container is partitioned by a water-permeable filtering material in the inlet chamber and the outlet chamber, by adding magnetic powder to the sludge suspension in the sludge suspension An inflow pipe for allowing a sludge suspension containing magnetic powder-containing sludge formed by binding the magnetic powder to sludge is provided in the inflow chamber , and an outflow pipe for allowing the treated water that has passed through the water-permeable filter body to flow out. Provided in an outflow chamber , using a magnetic material for at least a part of the water-permeable filter, and when the sludge suspension passes through the water-permeable filter, the magnetic powder-containing sludge in the sludge suspension, Adsorbing to the magnetic material of the water-permeable filter body, and forming a dynamic filtration layer on the water-permeable filter material, separating the magnetic powder-containing sludge from the sludge suspension in the dynamic filtration layer , Solid-liquid separation device. The solid-liquid separation device according to claim 2, wherein the inflow chamber and the outflow chamber are partitioned by the water-permeable filter body arranged in a horizontal direction and a partition plate arranged in a vertical direction. The inflow chamber and the outflow chamber are partitioned by a partition plate arranged in a vertical direction, and a plurality of filter body modules are provided on the inflow chamber side of the partition plate, and the filter body module supports the water-permeable filter body. 3. The solid-liquid separator according to claim 2, wherein the solid-liquid separator is installed on both sides of the body, and the inside of the support is communicated only with the outflow chamber via the partition plate. Instead of the water-permeable filter body using a magnetic material for at least a part of the above, the water-permeability obtained by winding a flexible plastic magnet in a spiral shape with a spacer on the outer periphery of a pipe-shaped support member arranged in the vertical direction 3. The solid-liquid structure according to claim 2, wherein a filter body is installed inside the container, and the inflow chamber is defined in a lower portion of the water-permeable filter body wound in a spiral shape, and the outflow chamber is defined in an upper portion. Separation device. 5. The solid-liquid separator according to claim 3, wherein a concentrated sludge extraction pipe is provided in the inflow chamber, and a pressurized air introduction pipe and an exhaust pipe are provided in the outflow chamber. A pump for circulating the activated sludge suspension between the inflow chamber and the sludge storage tank is provided, and the outflow chamber and the treated water storage tank are connected via a pump different from the pump. The solid-liquid separator according to claim 5.

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