JP2006320777A - Waste water treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste water treatment apparatus capable of reducing power consumption, facility cost, running cost or the like, and dealing with both of the clarification of waste water and the volume reduction of sludge in an activated sludge method. <P>SOLUTION: This apparatus is provided with: a liquid dispersion means 13 provided inside a partition member 12 sectioning the upper part of a treatment tank 11 into an inside and an outside; a treated water overflow weir 14 provided outside the partition member; a sludge take-out part 15 at a bottom part of the treatment tank; and a flow-in part 16 of treating object liquid. The liquid dispersion means 13 is provided with: a liquid dispersion plate 17 having a a bottom plate 21 disposed under a liquid level and a widened face 22 with a widened end 22a disposed below the liquid level; a liquid rising pipe 18 with an upper end opened at the central part of a bottom plate of the liquid dispersion plate 17 and with a lower end opened near the bottom plate of the treatment tank; rotary blades 19 rotating in liquid at the central part of the bottom plate of the liquid dispersion plate; and a driving means 20 rotating the rotary blades. The sludge-containing liquid on the liquid dispersion plate is dispersed toward the circumference thereof by the rotation of the rotary blades, and is dropped into the inside of the partition member while being made in contact with the air. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wastewater treatment apparatus, and more specifically, purifies sludge such as sewage by an activated sludge method using activated sludge, or treats excess sludge in an aerobic state to reduce sludge. It is related with the waste water treatment equipment for.

  Wastewater treatment by the activated sludge method is activated by mixing the activated sludge and wastewater in the aeration tank with the air discharged from the aeration apparatus by flowing the wastewater (raw water) into the aeration tank having the aeration (aeration) apparatus at the bottom. Oxygen is supplied to the sludge, and the wastewater is purified by decomposing organic substances contained in the wastewater with activated sludge (see, for example, Patent Document 1).

Further, in order to reduce the amount of excess sludge generated in the wastewater treatment facility, a method has been proposed in which ozone is added to the excess sludge to destroy the microbial cell membrane, thereby solubilizing and reducing the amount of sludge generated ( For example, see Patent Document 2.)
JP-A-8-52486 Japanese Patent No. 2973761

  In the wastewater treatment using the conventional aeration tank, the power consumption of the aeration blower for supplying compressed air to the aeration apparatus is extremely large, and there is a strong demand for reduction of the power consumption. In addition, if ozone is used to reduce sludge, it cannot be said that the amount of power consumed to generate ozone is small, and equipment to prevent ozone leakage is required, including maintenance of ozone generation equipment. And it requires a lot of expense.

  Accordingly, the present invention provides a wastewater treatment apparatus capable of reducing both power consumption, equipment cost, running cost, etc., and capable of both wastewater purification treatment and sludge reduction treatment by the activated sludge method. It is an object.

  In order to achieve the above object, the waste water treatment apparatus of the present invention comprises a cylindrical partition member that divides the upper part of a bottomed cylindrical treatment tank into the inside and the outside, and a liquid dispersing means provided at the inner central portion of the partition member And a treated water overflow weir provided on the outside of the partition member, a sludge extraction part for extracting sludge from the bottom of the treatment tank, and an inflow part for allowing the liquid to be treated to flow into the treatment tank, A liquid having a disk-shaped bottom plate and a spread surface that spreads upward from the periphery of the bottom plate, the bottom plate being disposed below the liquid level, and the widening end of the spread surface being disposed on the liquid level Dispersion plate, liquid riser with upper end opened to the center of the bottom of the liquid dispersion plate and lower end opened near the bottom of the treatment tank, and the axis of rotation of the liquid dispersion plate in the center on the bottom plate of the liquid dispersion plate in the vertical direction And a driving means for rotating the rotor blade, the rotor blade being rotated. The liquid sludge-containing liquid on the dispersion plate is dispersed around the liquid distributor plate, is characterized in that is dropped inside the partition member while in contact with air I.

  Further, the waste water treatment apparatus of the present invention provides an air introduction means for closing the upper opening of the partition member, providing exhaust means for exhausting the interior of the partition member, and introducing air below the expansion surface of the liquid dispersion plate. And a pumping means for rotating integrally with the rotor blade is provided inside the liquid riser pipe.

  Further, the waste water treatment apparatus of the present invention is provided at the periphery of the upper end opening of the liquid riser pipe that rises from the vicinity of the bottom of the treatment tank to a position lower than the liquid level, and the outer edge part is above the liquid level. A protruding liquid dispersion plate, a rotating blade rotating in the liquid inside the liquid dispersion plate, and a driving means for rotating the rotating blade, and the sludge-containing liquid is removed from the outer edge of the liquid dispersion plate by the rotation of the rotating blade. It is characterized in that it is dispersed in the air from the part and dropped onto the liquid surface in the treatment tank while being in contact with air.

  According to the wastewater treatment apparatus of the present invention, the sludge-containing liquid is dispersed and brought into contact with the air by the rotating blades rotating in the liquid surface portion, so that the power consumption is lower than that of the aeration blower that diffuses from the liquid. In addition to the reduction, the sludge-containing liquid at the bottom of the tank rises to the top of the tank through the liquid riser, so that the stirring in the treatment tank can be performed simultaneously.

  In addition, the upper opening of the partition member is closed and the partition member is exhausted, and air is introduced below the spread surface, so that sludge and air that are dispersed from the liquid dispersion means and fall to the liquid surface are efficiently removed. Good contact. Furthermore, since the scum that has floated on the liquid surface due to the air flow from the air introduction section can be moved to the sludge-containing liquid dropping position, the scum can be effectively crushed by the falling sludge-containing liquid. Furthermore, by providing the liquid lifting means inside the liquid riser pipe, the sludge-containing liquid at the bottom of the treatment tank can be efficiently raised toward the liquid dispersion plate.

  1 to 3 show a first embodiment in which the waste water treatment apparatus of the present invention is applied to purification of sewage by an activated sludge method. FIG. 1 is a schematic front view of the waste water treatment apparatus, and FIG. FIG. 3 is an explanatory view showing an operating state of the waste water treatment apparatus.

  In the wastewater treatment apparatus shown in this embodiment, a cylindrical partition member 12 is provided on the upper part of the treatment tank 11 having the bottom of the cylindrical body having an inverted conical shape, and the upper part of the treatment tank 11 is partitioned inward and outward. A liquid dispersion means 13 is provided at the inner central portion of the liquid and a treated water overflow weir 14 is provided outside the partition member 12 for allowing the treated water to flow out. In addition, a sludge extraction part 15 for extracting excess sludge is provided at the bottom of the treatment tank 11, and sewage (raw water) that is a liquid to be treated flows into the treatment tank 11 into the upper part inside the partition member 12. An inflow portion 16 is provided.

  The liquid dispersion means 13 includes a liquid dispersion plate 17 disposed on the liquid surface portion, a liquid riser pipe 18 provided below the liquid dispersion plate 17, and a rotating blade 19 that rotates on the upper surface portion of the liquid dispersion plate 17. And a motor 20 which is a driving means for rotating the rotary blade 19. The liquid dispersion plate 17 is formed in a dish shape having a disc-shaped bottom plate 21 in which the upper end of the liquid riser pipe 18 is opened at the center and an expanded surface 22 that expands upward from the periphery of the bottom plate 21. The bottom plate 21 is disposed below the liquid level, and the expanded end (outer edge portion) 22a of the expanded surface 22 is disposed so as to protrude above the liquid level.

  The rotary blade 19 includes a flat plate blade 19a shown in FIG. 2A and a curved blade 19b whose blade tip is bent rearward in the rotation direction, and is provided in the vertical direction provided at the center of rotation. Are connected to the motor 20 via the drive shaft 23. The rotor blades 19 are driven by a motor 20 to rotate at high speed in the liquid on the upper surface portion of the bottom plate 21, and the liquid containing the sludge on the bottom plate 21 is spread along the expanding surface 22 by centrifugal force. Are blown off to the outer periphery of the material, dispersed in the air, and dropped inside the partition member 12.

  The liquid rising pipe 18 is provided vertically below the bottom plate 21 toward the bottom of the treatment tank 11, and the sludge-containing liquid on the bottom plate 21 is rotated around the outer periphery of the liquid dispersion plate 17 by the rotation of the rotary blade 19. When the liquid on the bottom plate 21 is reduced by being dispersed in the liquid, the sludge containing liquid at the bottom of the treatment tank 11 is dispersed in the liquid riser pipe 18 due to the difference in water level inside and outside the pipe and the suction force generated at the center of the rotary blade 19. It will be in the state where it rises toward the plate 17.

  As shown in FIG. 3, the sludge-containing liquid scattered and dispersed in the air from the expanded end 22 a of the expanded surface 22 by the rotor blade 19 directly drops into the air until it falls to the liquid surface inside the partition member 12. It contacts and absorbs oxygen necessary for the activity of aerobic microorganisms and facultative anaerobic microorganisms in activated sludge from the air. At the same time, the sludge-containing liquid at the bottom of the treatment tank 11 rises in the liquid riser 18, so that the activated sludge that has absorbed oxygen descends from the inside of the partition member 12 toward the bottom of the treatment tank 11. By forming a circulation flow in and out of the liquid riser pipe 18 in this way, the inside of the treatment tank 11 can be appropriately stirred, and in particular, the diameter of the treatment tank at the portion where the lower end of the liquid riser pipe 18 is opened. By making small, the flow rate of this part can be raised and sewage and activated sludge can be mixed effectively.

  In this way, by rotating the rotor blade 19, oxygen is supplied to the activated sludge and the sludge containing liquid in the treatment tank 11 is agitated, and organic matter in the sewage is decomposed by absorption and metabolism of the activated sludge. Water purification is performed. Furthermore, by appropriately setting the conditions such as the volume of the treatment tank 11 and the amount of sludge-containing liquid dispersed by the liquid dispersion means 13, a denitrification reaction using organic matter in the sewage as a hydrogen donor is performed in the lower part of the treatment tank 11. Since the nitrification reaction of ammonia nitrogen by activated sludge that has absorbed oxygen progresses at the upper part, denitrification treatment for removing nitrogen content in the sewage can be performed at the same time. Moreover, the sludge containing liquid of the quantity corresponding to the amount of sewage flowing into the treatment tank 11 from the inflow part 16 rises outside the partition member 12, and the solid-liquid separation is performed in the ascending process, and the process in which the activated sludge is separated. Water flows out of the treatment tank 11 over the treated water overflow weir 14. Further, a part of the activated sludge that has settled at the bottom of the treatment tank 11 is extracted as excess sludge from the sludge extractor 15 and sent to the sludge treatment facility.

  In addition, since the rotary blade 19 disposed near the liquid surface is merely rotated by the motor 20, the power consumption can be greatly reduced as compared with the power consumption of the aeration blower in the conventional aeration tank. Furthermore, since nitrogen can be removed, the equipment configuration can be simplified compared to conventional wastewater treatment equipment that requires an anaerobic tank (anoxic tank) separately from the aeration tank, and the equipment cost and operation are reduced. Costs can be reduced. Further, when the sludge-containing liquid dispersed by the liquid dispersion means 13 falls on the liquid surface, the scum 24 that has floated on the liquid surface can be pulverized and re-sed by the dropping energy, so that the scum removing device or scum pulverization can be performed. There is no need to provide a device.

  The size of the partition plate 12 can be set as appropriate according to the opening area of the treatment tank 11, the amount of treated water, and the liquid dispersion state from the liquid dispersion means 13, and the sludge-containing liquid dispersed from the liquid dispersion means 13. May be set so that it does not fall over the partition plate 12 to the treated water overflow weir 14 side and sufficient solid-liquid separation can be performed outside the partition plate 12. Furthermore, the position of the inflow portion 16 can be provided at an arbitrary position depending on the state of the treatment tank 11 as long as the liquid to be treated that has flowed into the treatment tank 11 does not exceed the treated water overflow weir 14. The liquid to be processed may be allowed to flow into the interior of 18.

  Further, the shape of the liquid dispersion plate 17 is also arbitrary, and the spread surface 22 is not limited to a conical surface, and the whole or a part thereof may be a curved surface, or may be an inverted conical shape including the bottom plate 21, The widened end 22a of the widened surface 22 is not circular, but may have a sawtooth shape or a wave shape, a protrusion may be provided on the surface of the widened surface 22, the widened surface 22 may be an uneven surface, a different inclination angle, It can also be formed by combining expanded surfaces of curvature. Further, depending on the installation conditions of the liquid dispersion means 13, the liquid dispersion plate 17, the liquid riser pipe 18 and the rotary blade 19 constituting the liquid dispersion means 13 may be integrally formed, and these may be integrally rotated by the motor 20. Is possible. Further, the rotor blade 19 can be provided with a propeller-like twist.

  FIG. 4 is a schematic front view showing a second embodiment of the waste water treatment apparatus of the present invention. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the wastewater treatment apparatus shown in this embodiment, the upper opening of the partition member 12 is closed by the top plate 31, and exhaust gas is exhausted as an exhaust means for exhausting the space surrounded by the partition member 12, the top plate 31 and the liquid level. An exhaust pipe 33 connected to the blower 32 is provided on the top plate 31, and an air introduction part 34 for introducing air is provided below the expanded surface 22 of the liquid dispersion plate 17.

  As described above, the inside of the partition member 12 closed by the top plate 31 is sucked and exhausted by the exhaust blower 32, and the air introduction part 34 communicated with the outside air is provided below the spread surface 22, thereby Since the flow of the introduced air and the flow of the sludge-containing liquid dispersed by the liquid dispersion means 13 are crossed, the sludge-containing liquid can be reliably brought into contact with fresh air, Oxygen can be supplied efficiently.

  Further, by directing the flow of air introduced from the air introduction section 34 toward the outer peripheral surface of the liquid surface, the scum 24 that has floated in the vicinity of the liquid dispersion means 13 is moved to a position where the sludge-containing liquid falls to the liquid surface by the air flow Therefore, the scum 24 can be prevented from staying in a large amount around the liquid dispersion means 13.

  FIG. 5 is a schematic front view showing a third embodiment of the waste water treatment apparatus of the present invention. In the wastewater treatment apparatus shown in this embodiment, the drive shaft 23 of the rotary blade 19 is extended downward, and a screw 35 that is a pumping means that rotates integrally with the rotary blade 19 is provided inside the liquid rising pipe 18. Provided. By providing such a screw 35 and pumping up the sludge-containing liquid at the bottom of the treatment tank toward the liquid dispersion plate 17, a large amount of sludge-containing liquid is raised as compared with the liquid volume due to the action of the rotary blade 19 described above. Therefore, oxygen can be supplied to the activated sludge more effectively, and the sludge-containing liquid in the treatment tank 11 can be stirred and mixed effectively. Moreover, even when the liquid depth of the processing tank 11 is large or when the viscosity of the sludge-containing liquid is high, the sludge-containing liquid at the bottom of the tank can be reliably and rapidly raised.

  The pumping means is not limited to the screw 35, and a propeller or the like can be used. The drive shaft 23 is extended to the lower end of the liquid riser pipe 18 or below to provide a propeller or the like, It can also form so that a sludge containing liquid may be stirred.

  Moreover, the waste water treatment apparatus of the present invention can be used for aerobic digestion of excess sludge almost as it is. For example, when the wastewater treatment apparatus shown in the first embodiment is used for sludge treatment, excess sludge that has flowed into the treatment tank 11 from the inflow portion 16 is accompanied by the circulation flow generated by the rotation of the rotary blade 19 described above. Then, it mixes with sludge that has absorbed oxygen and descends toward the bottom of the tank in an aerobic state. Further, the scum 24 generated in the tank and floating on the liquid surface is pulverized by the drop impact of the sludge-containing liquid (sludge suspension) dispersed by the liquid dispersion plate 17 and re-sedimented.

  Here, surplus sludge (activated sludge) is an aggregate of microorganisms, and the microorganisms repeat growth and death. This death rate is about 3 to 4% per day on average, in other words, microorganisms will die if cultured for about 30 days. The dead microorganisms become microbial bodies or energy necessary for growth by predation by other microorganisms. Therefore, the sludge gradually disappears by repeating the process of microbial growth, death and predation. That is, aerobic digestion of activated sludge utilizes the fact that sludge is mineralized by keeping the sludge in an aerobic state, and the process of growth, killing and predation of microorganisms in the aerobic state is repeated. As a result, a certain amount or more of microorganisms are killed and mineralized, and sludge is reduced.

  In the present invention, the contact between the sludge and the air for making the sludge aerobic can be performed simply by rotating the rotor blade 19 of the liquid dispersion means 13 with the motor 20, and at the same time in the treatment tank 11. Since the sludge can be circulated, the amount of power consumption can be greatly reduced as compared with the case where an aeration blower or a circulation pump is used. Furthermore, since there is no portion where the sludge is clogged, no cleaning work is required, and continuous processing for a long time can be continued in a stable state at low cost.

  Normally, one liquid dispersion means 13 is arranged as shown in the above-mentioned embodiment for one treatment tank 11 to form one waste water treatment apparatus, but the liquid level of the treatment tank 11 is sufficiently wide. If the treated water overflow weir 14 is at a sufficiently separated position, the liquid rising pipe 18 rising from the vicinity of the bottom of the processing tank 11 to a position lower than the liquid level, and the upper end opening of the liquid rising pipe 18 are as described above. The liquid dispersion plate 17 provided at the periphery of the liquid dispersion plate, the outer edge of which protrudes upward from the liquid surface, the rotating blade 19 that rotates in the liquid inside the liquid dispersion plate 17, and drive means for rotating the rotating blade 19 ( It is also possible to install a plurality of liquid dispersing means 13 formed by the motor 20) in one processing tank.

It is a schematic front view of the waste water treatment apparatus which shows the 1st example of this invention. It is a schematic plan view which similarly shows a liquid dispersion | distribution means. It is explanatory drawing which similarly shows a sewage treatment state. It is a schematic front view of the waste water treatment apparatus which shows the 2nd form example of this invention. It is a schematic front view of the waste water treatment apparatus which shows the 3rd form example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Treatment tank, 12 ... Partition member, 13 ... Liquid dispersion means, 14 ... Treatment water overflow weir, 15 ... Sludge extraction part, 16 ... Inflow part, 17 ... Liquid dispersion plate, 18 ... Liquid riser, 19 ... Rotary blade 20 ... motor, 21 ... bottom plate, 22 ... expanded surface, 22a ... expanded end (outer edge), 23 ... drive shaft, 24 ... scum, 31 ... top plate, 32 ... exhaust blower, 33 ... exhaust pipe, 34 ... Air introduction part, 35 ... screw

Claims (4)

  A cylindrical partition member that divides the upper part of the bottomed cylindrical processing tank into the inside and outside, a liquid dispersion means provided at the inner center of the partition member, and a treated water overflow weir provided outside the partition member And a sludge extraction part for extracting sludge from the bottom of the treatment tank, and an inflow part for allowing the liquid to be treated to flow into the treatment tank, and the liquid dispersion means rises from the vicinity of the bottom of the treatment tank to a position lower than the liquid level. A liquid riser pipe, a liquid dispersion plate provided at a peripheral edge of the upper end opening of the liquid riser pipe, the outer edge portion of the expanded surface that is expanded upward, and an inner side of the expanded surface. A rotating blade rotating in the liquid with its rotation axis oriented in the vertical direction, and a driving means for rotating the rotating blade, and the sludge-containing liquid is dispersed in the air from the outer edge of the liquid dispersion plate by the rotation of the rotating blade. And let it fall inside the partition member while being in contact with air Waste water treatment apparatus according to claim.   The upper opening of the partition member is closed, exhaust means for exhausting the interior of the partition member is provided, and an air introduction portion for introducing air is provided below the expanded surface of the liquid dispersion plate. Item 1. A wastewater treatment apparatus according to item 1.   The waste water treatment apparatus according to claim 1 or 2, wherein a pumping means for rotating integrally with the rotor blade is provided inside the liquid riser pipe.   A liquid riser that rises from the vicinity of the bottom of the treatment tank to a position lower than the liquid level, a liquid dispersion plate that is provided at the periphery of the upper end opening of the liquid riser, and whose outer edge protrudes above the liquid level; and the liquid dispersion A rotating blade rotating in the liquid inside the plate, and a driving means for rotating the rotating blade, and the sludge-containing liquid is dispersed in the air from the outer edge of the liquid dispersion plate by the rotation of the rotating blade and comes into contact with air The waste water treatment apparatus is characterized by being dropped on the liquid level in the treatment tank.

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