JP4262069B2 - Magnetic separation device and waste water treatment device using the same - Google Patents

Description

The present invention relates to a magnetic separation device and a wastewater treatment device using the same , and more specifically, a magnetic separation device for separating sludge added with magnetic powder from an activated sludge suspension, and a wastewater using the magnetic separation device. The present invention relates to a wastewater treatment apparatus that performs water treatment such as sewage treatment with activated sludge to which magnetic powder is added .

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).
Japanese Patent Publication No. 63-59759

  In the conventional general wastewater treatment equipment to which the magnetic separation method is applied, when the activated sludge is separated only by the magnetic separation equipment, high magnetic separation performance is required. Invite up. Moreover, if 100 kg of organic matter is processed by a general activated sludge method, about 40 to 70 kg of excess sludge is generated. If this excess sludge is drawn out of the system as it is, it will adhere to the excess sludge. Since the magnetic powder is also discharged out of the system, the magnetic powder must be frequently added, resulting in an increase in operating cost.

Therefore, the present invention provides a magnetic separation device that can efficiently separate activated sludge (magnetic powder-containing sludge) to which magnetic powder is added, and a magnetic separation method using the magnetic separation device in a wastewater treatment device using the activated sludge method. It is an object of the present invention to provide a wastewater treatment apparatus that can significantly reduce the amount of excess sludge generated and improve the water treatment efficiency.

In order to achieve the above object, a magnetic separation device of the present invention is a magnetic separation device that separates magnetic powder-containing activated sludge in an activated sludge suspension from liquid by magnetic force, and the magnetic separation device comprises activated sludge. A magnetic separation tank having an inflow portion and an outflow portion of the suspension, an endless belt having a magnet disposed on the surface, a scraper for scraping off the activated sludge containing magnetic powder attached to the endless belt, and a scraper. A sludge recovery trough for recovering the activated sludge containing magnetic powder, a gantry suspended over the magnetic separation tank, a drive device for driving the endless belt installed on the gantry, and the activated sludge suspension A drive shaft of the endless belt disposed above the liquid surface of the liquid, a driven shaft of the endless belt disposed below the liquid surface of the activated sludge suspension, and a support arm provided at a lower portion of the gantry. And having the Jiude is characterized in that it comprises a bearing portion for rotatably supporting the drive shaft in a state of being positioned on the liquid surface.

Further, the wastewater treatment apparatus of the present invention includes an aerobic treatment tank that performs water treatment with magnetic powder-containing activated sludge to which magnetic powder is added, and an activity that is provided in the outflow part of the aerobic treatment tank and flows out of the outflow part. The magnetic separation device that separates the magnetic powder-containing activated sludge in the sludge suspension from the liquid by magnetic force, and the path for returning the magnetic powder-containing activated sludge separated by the magnetic separation device to the upstream portion of the aerobic treatment tank When was separated magnetic powder containing active sludge remaining in the activated sludge suspension flowing out from the magnetic separation device and solid-liquid separation means for separating from the liquid, the magnetic powder-containing active sludge in the solid-liquid separation means processing A path for extracting water, a path for returning the activated sludge containing magnetic powder separated by the solid-liquid separation means to the upstream portion of the aerobic treatment tank, and an upstream of the aerobic treatment tank separated by the solid-liquid separation means At least the activated sludge containing magnetic powder returned to the Solubilization for some, is characterized by and a solubilization-volume reduction means for performing volume reduction process.

  According to the waste water treatment apparatus of the present invention, in the water treatment by the activated sludge method, the activated sludge is separated in two stages of magnetic separation by magnetic force and normal solid-liquid separation, whereby the total amount of activated sludge by magnetic separation. Therefore, the magnetic separation means can be greatly reduced in size and cost. In addition, a part of the activated sludge to be returned to the aerobic treatment tank is solubilized, reduced in volume, or sterilized as necessary, so that a part of the returned sludge is biologically stored in the aerobic treatment tank. Since it can decompose | disassemble by a process, generation | occurrence | production of excess sludge can be reduced.

Further, the magnetic separation apparatus of the present invention, as well as to bridge the frame on top of a magnetic separation tank provided in the outlet portion of the aerobic treatment tank which is formed as described above, by the support arm provided in the lower portion of the frame by forming such suspend the endless belts, it is possible to units of the magnetic separation apparatus, equipment cost, Hakare be reduced such installation costs, further, so that the inspection of the magnetic separation device also allows from the pedestal Therefore, the efficiency of maintenance work can be improved.

Figure 1 shows a schematic longitudinal sectional view showing an embodiment of a waste water treatment apparatus, FIG. 2 is also a schematic plan view, FIG. 3 is a basic configuration of a magnetic separation means to be used for waste water treatment apparatus shown in FIGS. 1 and 2 It is explanatory drawing.

  This wastewater treatment device is a preferred method for purifying water by adding activated sludge (magnetic sludge containing activated sludge) added with magnetic powder to raw water from which suspended components etc. have been removed at the first place of sedimentation, etc., and performing aeration treatment. An air treatment tank 11, a magnetic separation means 12 for separating most of the activated sludge contained in the activated sludge suspension flowing out of the aerobic treatment tank 11 from the liquid by magnetic force, and an outflow from the magnetic separation means 12 The final sedimentation basin 13 as solid-liquid separation means for separating the remaining activated sludge in the activated sludge suspension from the liquid is integrally formed, and at the bottom of the aerobic treatment tank 11, A plurality of air diffusers 14 are provided.

  Further, the magnetic separation means 12 returns a magnetic separation sludge return path for returning the activated sludge containing magnetic powder separated by the magnetic separation means 12 toward the upstream portion of the aerobic treatment tank 11, in this embodiment, the raw water inflow pipe 15. 16 is provided, and the final sedimentation basin 13 is provided with a sedimentation separation sludge return path 17 that returns the activated sludge containing magnetic powder separated at the final sedimentation site toward the raw water inflow pipe 15. The aerobic treatment tank 11 has a width of about 5 to 10 m and a length of about 50 to 150 m, and the final sedimentation site 13 has a length of about 20 m. In addition, an inflow gate 13a and a rectifying plate 13b are provided in the inflow portion of the final sedimentation basin 13, and a treated water outflow portion 13c is provided in the upper portion on the downstream side.

  In order to make the activated sludge subjected to water treatment in the aerobic treatment tank 11 into a state in which the activated sludge can be magnetically separated by the magnetic separation means 12, magnetic powder is added and mixed in advance, and the magnetic sludge is adsorbed and held in the activated sludge. It is necessary to leave it in a state of being allowed to stay. 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 the magnetic powder is too low, a strong magnet such as a superconducting magnet is required to separate the activated sludge. Conversely, if the concentration is too high, the cost of the magnetic powder will increase. The MLVSS of the activated sludge is preferably in a concentration range of 0.01 to 10 with respect to 1, and normally, it may be set to have a concentration similar to that of the activated sludge MLVSS.

  When such magnetic powder is put into the activated sludge suspension at an appropriate position in the aerobic treatment tank 11 or the like, it immediately becomes adsorbed and held by the activated sludge, and becomes activated sludge containing magnetic powder attracted to the magnet. . Since most or all of this magnetic powder-containing activated sludge circulates with the return sludge, the addition and mixing of the magnetic powder to the activated sludge suspension usually only needs to be performed once before starting the magnetic separation. However, it can be added as appropriate according to 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.

  The activated sludge suspension obtained by mixing the aerated treated water purified by the aerobic treatment tank 11 and the activated sludge can be separated only by the magnetic separation means 12, but in this embodiment, the magnetic separation means is used. 12 and final sedimentation basin 13 are separated in two stages. Therefore, in the magnetic separation means 12, it is not necessary to magnetically separate the entire amount of the magnetic powder-containing activated sludge in the activated sludge suspension, and depending on the concentration of the magnetic powder-containing activated sludge and the load on the final sedimentation tank 13, What is necessary is just to be able to isolate | separate 50 to 99.5% or more of the magnetic powder containing activated sludge which exists in it.

  Various types of magnetic separation means 12 for separating the magnetic powder-containing activated sludge from the suspension can be used. For example, as shown in the explanatory diagram of FIG. 3, a magnetic separation tank 23 having an inflow portion 21 for sludge suspension and an outflow portion 22 for processing liquid, a rotating drum 24 having magnets disposed on the outer peripheral surface, and a rotating drum 24. A magnetic separation device including a scraper 26 that scrapes off the magnetic powder-containing sludge 25 adhering to and a sludge collection trough 27 that collects the magnetic powder-containing sludge 25 scraped off by the scraper 26 can be used. The rotating drum 24 is connected to a driving motor (not shown).

  A special magnet such as a superconducting magnet or an electromagnet can be adopted as the magnet used for the magnetic separation means 12 such as the rotating drum 24, but a permanent magnet that is generally available at a low cost, for example, a ferrite magnet. Can be used. Also, plastic magnets using ferrite magnets are stable and can be used even in an exposed state. However, depending on the situation of the installation location, the surface should be coated with a material excellent in durability, corrosion resistance, etc. It is preferable. Neodymium magnets, cobalt samarium magnets, and the like are powerful magnets, but they are susceptible to corrosion and need to be coated with anticorrosion. As the anticorrosion coating, various methods such as coating with a resin excellent in durability and corrosion resistance and coating with a stainless steel plate such as SUS304 can be adopted.

  The arrangement of the magnetic poles on the drum circumferential surface of the rotating drum 24 is preferably in a state in which N poles and S poles are alternately arranged at a magnetization interval of 2 to 20 mm. When the magnetizing interval is narrowed, the saturation adhesion amount of the magnetic powder-containing sludge is reduced, and when the magnetizing interval is widened, the adhesion force of the magnetic powder-containing sludge is weakened. The size (diameter and length) of the rotating drum 24 and the number of rotations during the magnetic separation process are arbitrary and can be selected according to the processing amount, taking into consideration the installation space, manufacturing cost, operating cost, etc. You only have to set it.

  The magnetic powder-containing sludge separated from the suspension by magnetic force can be collected by any method depending on the structure and shape of the magnet, and various shapes of magnets such as plates, disks, rods, etc. The sludge recovery means matched to the shape of the magnets can be combined. However, the magnetic powder-containing sludge 25 separated magnetically can be easily recovered in a continuous state by the combination of the rotating drum 24 and the scraper 26. . In addition, by using a rotating drum-shaped magnet, the configuration of the apparatus can be simplified, the manufacturing cost of the magnetic separation apparatus can be reduced, and maintenance and inspection can be easily performed.

  Among the microorganisms constituting the activated sludge, most of the floc-forming bacteria that easily hold magnetic powder are separated by the magnetic separation means 12, but the filamentous fungi and dispersible microorganisms that cannot hold magnetic powder alone are Most of them pass through the magnetic separation means 12 and settle in the final sedimentation tank 13. Therefore, by combining the magnetic separation means 12 and the final sedimentation tank 13, the activated sludge can be more reliably separated from the treated water.

  Therefore, by returning only the floc-forming bacteria separated and recovered by the magnetic separation means 12 to the aerobic treatment tank 11, the activated sludge in the aerobic treatment tank 11 can be mainly composed of floc-forming bacteria. The occurrence of bulking can be prevented. However, in this case, excess sludge is generated from the final sedimentation tank 13.

In order to prevent the generation of this excess sludge, it is possible to perform solubilization treatment and volume reduction treatment on a part or all of the activated sludge to be returned to the aerobic treatment tank 11 in the middle of the settling separation sludge return path 17. Solubilization / volume reduction means 18 is provided, and this solubilization / volume reduction means 18 is a mechanical treatment such as grinding, ozone treatment, chlorine treatment, hydrogen peroxide treatment, ultrasonic treatment, heat treatment, alkali treatment, alkali and super The activated sludge concentration in the system can be maintained in an appropriate range by returning to the aerobic treatment tank 11 after being subjected to a treatment such as a combined treatment of sonic waves or a combination treatment of alkali and heat. Filamentous fungi and the like can be eliminated, and excess sludge is not generated from the final sedimentation basin 13 . In addition, you may make it perform solubilization processing and volume reduction processing also to a part of activated sludge returned from the magnetic separation sludge return path | route 16. FIG.

  The raw water flowing into the wastewater treatment apparatus formed in this way is activated by being returned from the magnetic separation sludge return path 16 and the sedimentation separation sludge return path 17 after the suspended components and the like are separated and removed by a screen, first sedimentation basin, etc. It merges with the sludge and flows into the aerobic treatment tank 11. The organic matter in the raw water is purified by being treated with activated sludge by aeration treatment in the aerobic treatment tank 11. The activated sludge suspension after the aeration treatment flows into the magnetic separation means 12 provided at the most downstream part of the aerobic treatment tank 11, and most of the magnetic sludge containing activated sludge in the suspension is magnetically separated. Is done. The magnetic powder-containing activated sludge separated by the magnetic separation means 12 is returned to the upstream portion of the aerobic treatment tank 11 through the magnetic separation sludge return path 16, and the activated sludge suspension containing the remaining magnetic powder-containing activated sludge is And flows into the final sedimentation site 13.

  The activated sludge suspension flowing into the final sedimentation site 13 from the magnetic separation means 12 separates the sludge and the treated water by gravity settling, and the separated treated water is extracted from the upper treated water outflow portion 13c to the path 19. Then, the activated sludge containing magnetic powder settled at the bottom is returned to the upstream portion of the aerobic treatment tank 11 through the sedimentation sludge return path 17.

  The amount of activated sludge separated in the magnetic separation means 12 is set according to the balance between the activated sludge proliferation and autooxidation in the aerobic treatment tank 11 and the load on the final sedimentation tank 13. Is preferably set so that the activated sludge concentration in the activated sludge suspension flowing into the final sedimentation basin 13 is 3000 mg / L or less, preferably 2000 mg / L or less, particularly 1500 mg / L or less.

  Generally, the BOD concentration of sewage flowing into the aerobic treatment tank 11 of the sewage treatment plant is about 100 to 200 mg / L. In the aerobic treatment tank 11 under this load condition, when the activated sludge concentration is in the range of 5000 to 10000 mg / L, the amount of activated sludge is balanced with the auto-oxidation and almost no excess sludge is generated. . Therefore, by separating 80% of the activated sludge by the magnetic separation means 12, the activated sludge concentration flowing into the final sedimentation basin 13 can be 1000 to 2000 mg / L. Within this activated sludge concentration range, it is possible to perform sufficient sedimentation separation in the final sedimentation tank 13.

  At this time, even if the entire amount of the activated sludge separated in the magnetic separation means 12 and the final sedimentation basin 13 is returned to the aerobic treatment tank 11, under normal conditions, the balance between the proliferation of the activated sludge itself and the auto-oxidation. As a result, the increase in the activated sludge concentration is automatically stopped, so that the maintenance of the activated sludge concentration can be made unnecessary. At this time, the activated sludge concentration in the equilibrium state naturally fluctuates with the load fluctuation, but the activated sludge separation in the magnetic separation means 12 is performed so as not to exceed the allowable sludge concentration in the final sedimentation basin 13 even at the maximum load. By setting the amount, water treatment can be continued regardless of load fluctuations.

  Furthermore, by separating most of the activated sludge with the magnetic separation means 12, even if the activated sludge concentration in the aerobic treatment tank 11 is increased to some extent, it is possible to prevent the final sedimentation basin 13 from exceeding the allowable sludge concentration. Further, negative emission in which excess sludge from the outside is introduced into the aerobic treatment tank 11 and self-oxidized is also possible.

  Further, even when the amount of water flowing into the final sedimentation basin 13 increases due to the inflow of rainwater, the activated sludge adsorbing the magnetic powder has a higher specific gravity and better sedimentation than ordinary activated sludge. Thus, since floc-forming bacteria can be preferentially grown, sufficient sedimentation separation can be performed in the final sedimentation tank 13. For example, if the capacity of the magnetic separation means 12 is set so that the MLVSS concentration flowing into the final sedimentation basin 13 is about 1000 mg / L even when the flow rate is increased by rainwater, it is usually set to about 3 to 4 hours. Even if the residence time of the final sedimentation tank 13 is about half, the adverse effect on sedimentation separation can be almost eliminated.

  In addition, since the magnetic separation means 12 does not need to separate the entire amount of the magnetic powder-containing activated sludge, the required amount of activated sludge can be separated in an extremely short time, for example, separation and removal of the magnetic powder-containing activated sludge. Even when the rate is 99.5%, the magnetic separation process can be performed in several seconds to several tens of seconds, so that the process can be performed with a volume of about 1/100 to 1/10000 of the volume of the final sedimentation tank 12. Therefore, since the magnetic separation means 12 can be installed between the aerobic treatment tank 11 and the final sedimentation tank 13 in the existing water treatment facility with a small modification, the application to a new water treatment facility is possible. In addition, it can be easily applied to existing water treatment facilities.

In the wastewater treatment apparatus of this embodiment, the final sedimentation basin 13 for separating activated sludge by gravity is illustrated as the solid-liquid separation means subsequent to the magnetic separation means, but membrane separation is adopted as the solid-liquid separation means. Even in this case, clogging of the membrane can be suppressed and the interval between cleaning operations can be made wider than before, so that the lifetime of the membrane can be increased and the cost for membrane separation can be reduced. Further, the magnetic separation sludge return path 16 and the sedimentation separation sludge return path 17 can be combined into one.

4 and 5 show a first reference example of a magnetic separation apparatus that can be used in the wastewater treatment apparatus of this embodiment . FIG. 4 is a partially sectional front view, and FIG. 5 is a schematic side view. In the magnetic separation apparatus shown in this reference example, similarly to the magnetic separation means 13 shown in FIG. 3, the magnetic powder-containing activated sludge is separated by a rotating drum having magnets arranged on the outer peripheral surface.

  This magnetic separation apparatus has a magnetic separation tank 33 having an inflow portion 31 and an outflow portion 32 of an activated sludge suspension, two horizontal rotary drums 34 each having a magnet disposed on the outer peripheral surface, and attached to the horizontal rotary drum 34. Scraper 35 that scrapes off the activated sludge containing magnetic powder, sludge recovery trough 36 that collects the activated sludge containing magnetic powder scraped off by the scraper 35, a gantry 37 that spans the top of the magnetic separation tank 33, and the gantry A horizontal rotary drum driving device 38 installed on the base 37, a support arm 39 provided at the bottom of the gantry 37, and a bearing 40 provided at the lower end of the support arm 39.

  The inflow portion 31 is provided with a screen 41 having a large number of through holes so that coarse impurities do not enter the magnetic separation tank 33. A liquid receiver 42 is provided below the outflow part 32 and is connected to a separation liquid transfer part 43 provided on the side of the drum. Further, the sludge recovery trough 36 is also connected to a separated sludge transfer section 44 provided on the side of the drum. When this magnetic separation device is installed in a wastewater treatment device as described above, the separation liquid transfer unit 43 is connected to the inflow gate 13a of the final sedimentation basin 13, and the separated sludge transfer unit 44 is connected to the magnetic separation sludge return path 16. Will be.

  The horizontal rotary drum 34 is obtained by winding a plastic permanent magnet 46 around the outer peripheral surface of a drum main body 45 made of a magnetic material such as SS400 or SUS410, and both ends of the drum 45 are closed by end plates 47. In this embodiment, two horizontal rotary drums 34 are arranged in series, and a rotary shaft 48 is attached to the center of each end plate 47. The rotary shaft 48 is rotatably supported by the bearing portion 40 so as to be positioned above the liquid level of the magnetic separation tank 33, and a chain 49 is attached to the driving device 38 at one end of the rotary shaft 48. The sprocket 50 connected via is attached.

  In the wastewater treatment apparatus as described above, the magnetic separation device formed in this way is the outflow portion of the aerobic treatment tank 11, the flow path portion from the aerobic treatment tank 11 to the final sedimentation basin 13, or the final The magnetic separation tank 33 is positioned slightly below the liquid level of the activated sludge suspension flowing through these portions with the gantry 37 suspended over the upper edge of the inflow portion of the settling basin 13, and the bearing portion. It installs so that 40 may be located above a liquid level. By installing in this way, the magnetic powder-containing activated sludge in the activated sludge suspension flowing into the magnetic separation tank 33 from the inflow portion 31 is magnetically attached to the peripheral surface of the horizontal rotary drum 34 and separated from the liquid, It can be scraped off by the scraper 35 and extracted from the sludge recovery trough 36 to the separated sludge transfer section 44.

  Further, the horizontal rotary drum 34 is formed so as to be supported while being suspended from the gantry 37, and the bearing portion 40 is positioned above the liquid surface, so that the bearing portion 40 can be prevented from being contaminated with sludge or the like. . Furthermore, by appropriately setting the shape of the gantry 37, the horizontal rotary drum 34, the scraper 35, the bearing portion 40, etc. can be inspected on the gantry 37. In addition, by affixing the aerobic treatment tank etc. and the pedestal 37 so as to be detachable with appropriate fixing means, each part can be inspected, repaired and replaced with the magnetic separation device removed from the aerobic treatment tank etc. These workability can be improved significantly.

6 and 7 show a second reference example of a magnetic separation apparatus that can be used in the wastewater treatment apparatus of this embodiment . FIG. 6 is a partially sectional front view, and FIG. 7 is a schematic side view. The magnetic separation apparatus shown in this reference example separates magnetic powder-containing activated sludge using a disk-shaped magnet. In the following description, the same components as those in the magnetic separation apparatus shown in the first reference are denoted by the same reference numerals, and detailed description thereof is omitted.

In the second reference example, a large number of magnetic disks (disk-shaped magnets) 51 having magnets arranged on both surfaces are arranged at equal intervals with a spacer 53 sandwiched between one rotary shaft 52. A scraper 54 for scraping off the magnetic powder-containing activated sludge adhering to each magnetic disk surface and a sludge collection trough 55 for collecting the scraped-off magnetic powder-containing activated sludge are provided on the upper part. A baffle plate 56 for rectifying the flow of the activated sludge suspension and suppressing leakage of the magnetic powder-containing activated sludge is provided at the lower part. Similarly to the first reference example, the rotating shaft 52 is rotatably supported above the liquid level by a bearing portion 40 provided at the lower end of the support arm 39, and a driving device provided on the gantry 37. 38 is driven by the chain 49 and the sprocket 50.

  The magnetic disk 51 becomes more easily distorted as its diameter increases. For example, when the diameter is about 1000 mm, a thickness of about 20 mm is required to prevent distortion. If such a large disk is made of solid iron or the like, it becomes very heavy, which increases not only the production cost but also the power cost. Therefore, the magnetic disk 51 has a structure in which a thin magnetic material such as an iron plate is attached to both surfaces of a lightweight core made of plastic foam or the like, and a plastic permanent magnet is attached thereon. Can be reduced in weight and magnetic field can be strengthened. Note that if a plastic magnet is directly attached to a non-magnetic material such as plastic, the strength of the magnetic field will be lower than when a plastic magnet is attached to a magnetic material such as iron.

The magnetic separation apparatus shown in the second reference example is also installed in the outflow part or the like of the aerobic treatment tank 11 as described above, so that the magnetism in the activated sludge suspension flowing into the magnetic separation tank 33 from the inflow part 31 is obtained. The powder-containing activated sludge can be separated by the magnetic disk 51. The magnetic powder-containing activated sludge is separated from the sludge collection trough 54 to the separated sludge transfer section 44, and the liquid from which the magnetic powder-containing activated sludge is separated is transferred from the liquid receiver 42 to the separated liquid. Can be sent to each part. Further, the contamination of the bearing portion 40 can be prevented, and inspection, repair, and replacement of each portion can be easily performed as described above.

8 and 9 show a modification of the second reference example. FIG. 8 is a partially sectional plan view, and FIG. 9 is a schematic side view. This magnetic separation device uses a pipe-like hollow body as the rotating shaft 52 and forms a communication hole 57 in the spacer 53 that holds the magnetic disk 51 at equal intervals, and the liquid separated from the activated sludge containing magnetic powder The communication hole 57 is guided into the rotary shaft 52 and is sent from one end of the rotary shaft 52 to the separation liquid transfer unit 43. Other configurations may be the same as those of the second reference example.

FIG. 10 is a schematic front view showing a first embodiment of the magnetic separation device of the present invention. This magnetic separation apparatus constitutes a wastewater treatment apparatus according to the present invention by using it in the wastewater treatment apparatus shown in FIGS. 1 and 2 instead of the magnetic separation means 12 of the basic configuration, The separation device uses an endless belt 61 made of a magnetic material, a drive shaft 62 is disposed above the liquid surface, a driven shaft 63 is disposed below the liquid surface, and a scraper 64 and A sludge collection trough 36 is provided. In addition, the bottom surface of the magnetic separation tank 33, that is, the surface on the endless belt 61 side, is provided with a plurality of rows of concave grooves or ridges 65 extending in the direction from the inflow portion 31 to the outflow portion 32. Even when the belt 61 is bent, an interval in which the activated sludge suspension can flow can be secured between the magnetic separation tank 33 and the endless belt 61.

  The endless belt 61 is a belt in which a plastic magnet is attached to the outer surface of a belt body made of a thin plate-like or mesh-like metal magnetic body having flexibility so as to obtain predetermined tensile strength and magnetic field strength. be able to. Further, the endless belt 61 can be formed by magnetizing the metal magnetic body itself.

Further, as a second embodiment of the magnetic separation device of the present invention, as shown in the schematic front view of FIG. 11, the magnetic separation tank 33, the sludge recovery trough 36, the magnetic powder-containing activated sludge recovered in the sludge recovery trough 36, The scraper 64 and the sludge recovery trough 36 can be provided on the driven shaft 63 side by appropriately setting the shape and structure of the extraction path.

  The waste water treatment apparatus of the present invention can be applied to waste water treatment equipment for treating sewage and organic waste water. In addition, the magnetic separation device of the present invention can be used for a wastewater treatment device employing a magnetic separation method, and is particularly suitable for a large-scale wastewater treatment device.

It is a schematic longitudinal cross-sectional view which shows one example of a waste water treatment apparatus. Similarly, it is a schematic plan view. It is description which shows the basic composition of the magnetic separation means used for the waste water treatment equipment shown in FIGS. It is a partial cross section front view which shows the 1st reference example of a magnetic separation apparatus. It is a schematic side view similarly. It is a partial cross section front view which shows the 2nd reference example of a magnetic separation apparatus. It is a schematic side view similarly. It is a partial cross section top view which shows the modification of the 2nd reference example of a magnetic separation apparatus. It is a schematic side view similarly. It is a schematic front view which shows the 1st example of a magnetic separation apparatus of this invention which can be used for the waste water treatment apparatus which concerns on this invention. It is a schematic front view which shows the 2nd example of a magnetic separation apparatus of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Aerobic processing tank, 12 ... Magnetic separation means, 13 ... Final sedimentation basin, 13a ... Inflow gate, 13b ... Rectification plate, 13c ... Outflow part of treated water, 14 ... Aeration pipe, 15 ... Raw water inflow pipe, 16 ... Magnetic Separation sludge return path, 17 ... Sedimentation separation sludge return path, 18 ... Solubilization / volume reduction means, 21 ... Inflow part, 22 ... Outflow part, 23 ... Magnetic separation tank, 24 ... Rotating drum, 25 ... Magnetic powder containing sludge , 26 ... scraper, 27 ... sludge collection trough, 31 ... inflow part, 32 ... outflow part, 33 ... magnetic separation tank, 34 ... horizontal rotating drum, 35 ... scraper, 36 ... sludge collection trough, 37 ... mount, 38 ... drive Device: 39 ... Support arm, 40 ... Bearing part, 41 ... Screen, 42 ... Liquid receiver, 43 ... Separation liquid transfer part, 44 ... Separation sludge transfer part, 45 ... Drum body, 46 ... Plastic permanent magnet, 47 ... End plate 48 ... rotation 49 ... Chain, 50 ... Sprocket, 51 ... Magnetic disk, 52 ... Rotating shaft, 53 ... Spacer, 54 ... Scraper, 55 ... Sludge collection trough, 56 ... Baffle plate, 57 ... Communication hole, 61 ... Endless belt, 62 ... Drive shaft, 63 ... Drive shaft, 64 ... Scraper, 65 ... Projection

Claims (2)

A magnetic separation device for separating the activated sludge containing magnetic powder in the activated sludge suspension from the liquid by magnetic force, the magnetic separation device comprising: a magnetic separation tank having an inflow portion and an outflow portion of the activated sludge suspension; An endless belt having magnets disposed on the surface, a scraper for scraping off the activated sludge containing magnetic powder adhered to the endless belt, a sludge collecting trough for collecting the activated sludge containing magnetic powder scraped off by the scraper, and the magnetic A stand spanned over the upper part of the separation tank, a drive device for driving the endless belt installed on the stand, and a drive shaft of the endless belt disposed above the liquid level of the activated sludge suspension When the driven shaft of the endless belt disposed below the liquid surface of the activated sludge suspension, and a support arm provided in a lower portion of the frame, the support arm, the pre-SL drive shaft a state of being positioned on the liquid surface Magnetic separation device which is characterized in that it comprises a bearing portion for rotatably supporting. An aerobic treatment tank that performs water treatment with activated sludge containing magnetic powder to which magnetic powder is added, and a magnetic powder-containing activity in an activated sludge suspension that is provided at the outflow part of the aerobic treatment tank and flows out of the outflow part a path for returning the magnetic separation device of claim 1 wherein separating the sludge from the liquid in the magnetic force, the magnetic powder-containing activated sludge separated in the magnetic separator apparatus to an upstream portion of the aerobic treatment tank, wherein the magnetic separation device Solid-liquid separation means for separating the magnetic powder-containing activated sludge remaining in the activated sludge suspension flowing out from the liquid, and a path for extracting treated water separated from the magnetic powder-containing activated sludge by the solid-liquid separation means, A path for returning the activated sludge containing magnetic powder separated by the solid-liquid separation means to the upstream part of the aerobic treatment tank, and a magnetic powder separated by the solid-liquid separation means and returned to the upstream part of the aerobic treatment tank Solubilized in at least part of the contained activated sludge Management, waste water treatment apparatus characterized by and a solubilization-volume reduction means for performing volume reduction process.

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