JP2013063365A - Apparatus for aerobic biological treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for aerobic biological treatment which can achieve washing of a packed bed and oxygenation of the entire packed bed only by an aeration means, and further has a structure in which scale does not adhere to a diffusion hole provided for the aeration means.SOLUTION: The apparatus for aerobic biological treatmentincludes, in a treatment tank, a biological treatment means to which a support that supports aerobic microorganisms are filled, and the aeration means which is provided below the biological treatment means and rotates around a rotary shaft while supplying an oxygen-containing gas to the biological treatment means through two or more diffusion holes, wherein the diffusion hole is formed of an open end of a spouting pipe to spout the oxygen-containing gas in water, and waste sludge generated in the biological treatment means are peeled off from the support by the oxygen-containing gas supplied to the biological treatment means through any of the diffusion holes.

Description

  The present invention relates to a biological treatment apparatus using aerobic microorganisms, and more particularly to a biofilm aerobic biological treatment apparatus for attaching aerobic microorganisms to a carrier.

  A biofilm aerobic biological treatment device that attaches aerobic microorganisms to a carrier (hereinafter simply referred to as an aerobic biological treatment device) causes sludge consisting of suspended aerobic microorganisms to flow out of the system due to some problem (bulking) ) Compared with the floating activated sludge equipment that may cause a large amount of sludge, the added amount of sludge can be increased and the installation area of the equipment per unit treatment amount can be reduced. Have.

  However, in the aerobic biological treatment apparatus, the amount of aerobic microorganisms attached to the carrier increases with the operation, so the operation is interrupted and the excess sludge (excess aerobic microorganisms) attached to the carrier is removed by the washing operation. There is a need. As a result, since a relatively large amount of washing wastewater is generated, a washing wastewater receiving tank is required, and a receiving tank for retaining treated water that flows out while operation is interrupted is required.

  Therefore, an aerobic biological treatment in which a single cleaning air jetting means for cleaning a partial cross-section from the center of the tank to the outer periphery of the tank is attached to the lower part of the carrier packed bed and the cleaning air jetting means is rotated at a low speed. An apparatus has been developed (for example, Patent Document 1).

  According to the aerobic microorganism treatment apparatus described in Patent Document 1, since the cleaning air jetting unit rotates at a low speed, the partial cross-section packed bed located above the cleaning air jetting unit is washed, and then adjacent to it. The packed bed in the tank can be cleaned sequentially, such as by cleaning the packed bed of the partial cross section, so that it is not necessary to interrupt the apparatus, and the cleaning waste water receiving tank can be dispensed with.

Japanese Patent Laid-Open No. 8-80495

  In the aerobic microorganism treatment apparatus described in Patent Document 1, it is necessary to provide a diffuser means for supplying air for maintaining the water to be treated in the tank in an aerobic atmosphere separately from the cleaning air jet means. In addition, if the operation is continued for a long time, components such as calcium, magnesium, silica, etc. contained in the water may be deposited as scales on the air outlet of the cleaning pipe, etc., which prevents such scale accumulation. The method is not specifically described.

  The present invention aims to solve the above-mentioned problems in the conventional aerobic biological treatment apparatus, and to achieve the cleaning of the packed bed and the supply of oxygen to the entire packed bed only by aeration means. It is an object to provide a structure capable of stably supplying an oxygen-containing gas for a long period of time without being affected by the above.

  In order to solve the above problems, an aerobic biological treatment apparatus according to the present invention comprises a biological treatment means filled with a carrier carrying an aerobic microorganism, and a plurality of aeration holes provided below the biological treatment means. An aerobic biological treatment apparatus provided in the treatment tank with an aeration means rotating around a rotation axis while supplying an oxygen-containing gas to the biological treatment means through the aeration hole, wherein the aeration holes are the oxygen-containing gas. The surplus sludge generated in the biological treatment means is separated from the carrier by the oxygen-containing gas supplied to the biological treatment means through any of the air holes. It is made up of.

  According to such an aerobic biological treatment apparatus according to the present invention, the diffuser holes for supplying the oxygen-containing gas to the biological treatment means are provided in the diffuser means that rotates around the rotation axis. The region where the oxygen-containing gas is supplied from the pores moves with the rotation of the air diffusion means, and the oxygen-containing gas can be supplied to a wide region by a small number of air diffusion holes. Therefore, the number of diffused holes for supplying the oxygen-containing gas to the entire biological treatment means can be reduced as compared with the conventional apparatus, and the consumption of the oxygen-containing gas can be suppressed. As a result, it is possible to save power for oxygen supply that consumes a large amount of energy in the aerobic biological treatment apparatus, thereby reducing the operating cost of the apparatus.

  Further, since oxygen-containing gas supplied to the biological treatment means through any of the air holes provided in the diffusion means causes excess sludge generated in the biological treatment means to be peeled off from the carrier, oxygen supply to the biological treatment means The cleaning of the biological treatment means (that is, the removal of excess sludge from the carrier filled in the biological treatment means) is simultaneously performed by the aeration means. Therefore, by rotating the air diffuser while limiting the portion to be cleaned by the air diffuser in the biological treatment device, the cleaning portion can be moved to perform a substantially continuous partial cleaning. In addition, in other non-washing parts, the microorganism treatment can be continuously performed by the microorganisms attached to the carrier. As a result, the microbial treatment and the cleaning of the biological treatment means can be performed simultaneously in parallel, and there is no need to interrupt the microbial treatment for cleaning the biological treatment means. In addition, the part wash | cleaned by the aeration means in a biological treatment means may be one continuous area | region, and may be disperse | distributed to the several area | region.

  The aerobic biological treatment apparatus according to the present invention can perform microbial treatment and washing of the biological treatment means in parallel at the same time, so that stable microbial treatment can be performed over a long period of time. In the conventional apparatus that performs intermittent batch cleaning, the amount of microorganisms adhering to the carrier is greatly reduced by the cleaning operation, and there is a possibility that the water quality may be temporarily deteriorated and the processing capacity may be temporarily reduced. On the other hand, since the aerobic biological treatment apparatus according to the present invention realizes continuous washing by moving the part while washing a part of the biological treatment means, the washing of the part is excessive. Even if it is performed, the overall processing capacity is not greatly affected, and stable processing capacity can be continuously exhibited. In addition, unlike the conventional intermittent batch cleaning method, it is not necessary to interrupt the supply of the oxygen-containing gas through the air diffuser for cleaning, so the air diffuser is clogged by continuously operating the air diffuser. Can be prevented. As a result, the frequency of maintenance work for the air holes and the air diffuser can be greatly reduced, and the maintenance cost can be greatly reduced. Furthermore, since the clogging of the carrier is prevented by the above-described continuous cleaning mechanism, a stable processing ability can be exhibited even in a high load environment where the growth of microorganisms is fast.

  Since the aerobic biological treatment apparatus according to the present invention does not require a separate means for separating excess sludge from the carrier, it is easy to downsize and simplify the apparatus, and the aerobic biological treatment with a high capacity per unit capacity. The device can be realized at low cost.

  The air diffusion hole is composed of an opening end of an ejection pipe for ejecting oxygen-containing gas into water. According to such a configuration, it is possible to prevent the opening end from being blocked by scale deposition by sufficiently increasing the opening area of the opening end of the ejection pipe.

  It is preferable that the oxygen-containing gas is supplied into the water downward from the air diffusion holes. In this way, since the air holes are opened downward in the water, the air holes are prevented from being blocked due to the entrance of sediment and excess sludge. The diffuser hole may be opened obliquely downward as well as opened downward in the vertical direction.

  It is preferable that the air diffuser is provided with a portion having a large oxygen supply gas supply amount per unit time and a portion having a small amount. According to such a configuration, in a portion where the supply amount of the oxygen-containing gas per unit time is relatively large, the action of the sludge shearing force due to the bubbles is increased, and excess sludge is removed from the carrier filled in the biological treatment means. It becomes easy to peel. On the other hand, at a site where the supply amount of the oxygen-containing gas per unit time is relatively small, oxygen can be supplied to the biological treatment means while being dispersed by fine bubbles. In this way, by providing the diffuser means with different portions of the oxygen-containing gas supply amount, the action of the sludge shearing force due to the bubbles is relatively large, and the portion suitable for cleaning the carrier filled in the biological treatment means is fine. Since a portion suitable for the distributed supply of oxygen to the biological treatment means is generated by bubbles, it is possible to effectively perform the distributed supply of dissolved oxygen to the biological treatment means while washing the biological treatment means.

  The air diffuser has an introduction hole for introducing an oxygen-containing gas into the ejection pipe, and the opening area of the introduction hole is preferably less than or equal to the flow passage cross-sectional area of the ejection pipe. According to such a configuration, the amount of oxygen-containing gas ejected into the water from the opening end (that is, the diffuser hole) of the ejection pipe can be controlled by the opening area of the introduction hole, and stable without being affected by scale deposition or the like. An oxygen-containing gas can be supplied. For example, the introduction hole is formed by adhering one end of the ejection pipe (one end opposite to the opening end) to the side wall surface of the other pipe in a water-tight manner, and forming a small-diameter hole communicating the inside of the ejection pipe with the other pipe. It is formed in the structure perforated on the side wall surface of the tube.

  When the air diffuser has the introduction hole, the introduction hole is preferably configured such that the opening area distribution has two or more peaks. By providing introduction holes with different opening areas, the action of sludge shearing force due to bubbles is relatively large, suitable for cleaning the carrier filled in the biological treatment means, and for the supply of oxygen to the biological treatment means in a dispersed manner A suitable jet pipe is formed, and a part having a different supply amount of oxygen-containing gas per unit time is provided in the aeration means. Therefore, it is possible to effectively supply dissolved oxygen to the biological treatment means while washing the biological treatment means. Can be done. When a plurality of introduction holes are provided for one ejection pipe, the opening area value of the introduction holes is defined as the total area of the introduction holes for each ejection pipe.

  The configuration of the air diffuser is not particularly limited, and for example, the air diffuser may adopt a configuration having a main pipe radially extending from the rotation shaft and a branch pipe provided by branching from the main pipe. it can.

  It is preferable that the air diffuser is configured to have a peak in which the rotation radius distribution of the air diffuser repeatedly appears at a predetermined pitch. Here, the rotation radius distribution of the air diffuser represents a frequency distribution of the number of air diffusers with respect to the distance (rotation radius) from the rotation axis of the air diffuser to the center of gravity of the opening of the air diffuser. By adopting such a configuration, the oxygen-containing gas is supplied to the biological treatment means through the air diffusion holes at a predetermined pitch in the radial direction, and the oxygen-containing gas is supplied throughout the biological treatment means.

  The carrier preferably has a plurality of radially extending protrusions. According to such a configuration, since the bubbles of the oxygen-containing gas ejected into the water from the air diffusion holes are refined by the protrusions provided on the carrier, the amount of dissolved oxygen increases and the biological treatment means is filled. Fine bubbles are also supplied to the narrow portion of the carrier. As a result, the oxygen transfer efficiency, the oxygen supply efficiency, and the cleaning efficiency are improved, and the oxygen supply to the biological treatment means and the biological treatment means can be cleaned with a smaller amount of oxygen-containing gas than the conventional apparatus. The operation cost can be further reduced. Further, by providing a large number of radially extending protrusions on the carrier to improve the porosity of the carrier, it is possible to increase the surface area of the carrier and to retain a large amount of sludge, thereby improving the processing efficiency. .

  According to the aerobic biological treatment apparatus according to the present invention, the air diffusion holes for supplying the oxygen-containing gas to the biological treatment means are provided in the air diffusion means rotating around the rotation axis. Oxygen-containing gas can be supplied efficiently, and consumption of oxygen-containing gas is reduced. In addition, it is possible to perform microbial treatment continuously in other parts of the biological treatment means while washing a part of the biological treatment means, thus enabling stable operation over a long period of time while reducing the frequency of maintenance work. Thus, the maintenance cost can be greatly reduced. Furthermore, since it is not necessary to separately provide a means for cleaning the biological treatment means, the apparatus can be simplified and downsized.

It is a longitudinal cross-sectional view of the aerobic biological treatment apparatus which concerns on one embodiment of this invention. It is a top view of the aeration means with which the aerobic biological treatment apparatus of FIG. 1 was equipped. It is a longitudinal cross-sectional view of the ejection pipe | tube provided in the aeration means of FIG. It is a longitudinal cross-sectional view which shows an example of the air diffusion hole in a conventional apparatus. It is a line graph which shows opening area distribution of the introduction hole provided in the aeration means of FIG. It is a fragmentary longitudinal cross-sectional view of the aerobic biological treatment apparatus of FIG. It is a bar graph which shows the rotation radius distribution of the air diffusion hole provided in the air diffusion means of FIG.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an aerobic biological treatment apparatus according to an embodiment of the present invention. In FIG. 1, the aerobic biological treatment apparatus 1 includes a treatment tank 2, an inflow pipe 3 as a treated water supply means communicating with an upper portion of the treatment tank 2, one end formed at an open end, and the other end. An outflow pipe 4 as a treated water discharge means communicating with the lower part of the treatment tank 2 is provided. Further, in the outflow pipe 4, the outflow branch pipe 5 communicates with a position corresponding to the substantially same height as the water surface S in the treatment tank 2, and the water surface S in the treatment tank 2 is maintained at a predetermined height. .

  In the treatment tank 2, a biological treatment means 7 filled with a carrier 6 supporting aerobic microorganisms, a discharge pipe 8 opening downward, and a diffusion hole 9 as an opening end of the discharge pipe 8 are provided. An air means 10 is provided, and the air diffuser 10 is disposed below the biological treatment means 7. A conduit 11 is erected at the center of the treatment tank 2, and the lower end of the conduit 11 communicates with the air diffuser 10. The upper end of the conduit 11 has a rotating gas supply device 12, a speed reducer 13, and a motor 14. Is provided. A gas inflow pipe 15 is connected to the rotating gas supply device 12, and the oxygen-containing gas that has flowed into the rotating gas supply device 12 from the gas inflow tube 15 is supplied to the aeration means 10 through the conduit 11, and The water is supplied to the opening end, that is, downward from the air diffusion hole 9. Further, the rotation of the motor 14 is decelerated by the speed reducer 13 and transmitted to the conduit 11, the conduit 11 rotates as the axis of rotation, and accordingly, the air diffuser 10 rotates around the conduit 11. The rotational speed of the air diffuser 10 is not particularly limited, but the time required for one rotation is preferably in the range of 10 to 50 days, and more preferably in the range of 25 to 35 days. The air diffuser 10 may be configured to rotate continuously, or may be configured to move at a small angle intermittently at predetermined time intervals. Further, the supply of the oxygen-containing gas by the air diffuser 10 may be performed continuously, or may be an intermittent method in which the supply is temporarily suspended according to the degree of the excess sludge peeling from the carrier 6. .

  The carrier 6 is made of plastic, has an outer appearance that is substantially elliptical, and has a number of short protrusions (not shown) extending radially from the center. The porosity of the carrier 6 is about 95%, and a large amount of aerobic microorganisms can be retained in the voids. Note that the material and shape of the carrier 6 are not limited to the above, and may be configured so that a large amount of aerobic microorganisms can be retained.

FIG. 2 is a plan view of the air diffuser 10 provided in the aerobic biological treatment apparatus 1 of FIG. 1 as viewed from above. In FIG. 2, the air diffuser 10 has a main pipe 16 extending radially from the central portion and a number of branch pipes 17 branched from the main pipe. The main pipe 16 and the branch pipes 17 communicate with the ejection pipe 8. An introduction hole 18 is provided. Introducing hole 18, the hole 18a is substantially circular hole with a diameter of about 5 mm (about opening area 19.6 mm ^2), a substantially circular hole in a hole 18b having a diameter of about 15 mm (about opening area 176.7mm ²⁾ It consists of two types. In FIG. 2, a circle drawn by a two-dot chain line represents a virtual concentric circle having an interval of 100 mm centered on the rotation axis of the air diffuser 10, and is introduced into the introduction hole 18 (hole 18 a and hole 18 b). The communicating ejection pipe 8 is configured such that the center of gravity (center) of the opening end is arranged in the vicinity of the concentric circle.

  FIG. 3 is an enlarged longitudinal sectional view showing the structure of the ejection pipe 8 and the introduction hole 18. In the following, the structure in which the hole 18a as the introduction hole 18 communicates with the main pipe 16 will be described with reference to FIG. 3 as an example. The same applies to the structure in which the hole 18 a or the hole 18 b as the introduction hole 18 communicates with the branch pipe 17. In FIG. 3, one end of the ejection pipe 8 is formed as an air diffusion hole 9 at an opening end directed downward, and the other end is bonded to the main pipe 16 in a watertight manner. Further, the other end of the ejection pipe 8 is provided with a hole 18 a as an introduction hole 18 that communicates with the main pipe 16 and has a smaller cross-sectional area (opening area) than the ejection pipe 8. The oxygen-containing gas that has flowed from the main pipe 16 into the ejection pipe 8 through the hole 18a is supplied into the water from the air diffusion holes 9, and rises in the water as bubbles. The opening area of the hole 18a is smaller than the cross-sectional area of the ejection pipe 8, and the flow rate of the oxygen-containing gas flowing from the main pipe 16 into the ejection pipe 8 per unit time depends on the opening area of the hole 18a. Since there is a layer of oxygen-containing gas around the hole 18a provided in the air diffuser 10, scale does not adhere to the hole 18a, and a decrease in the flow rate of the oxygen-containing gas is prevented. When the aerobic biological treatment apparatus 1 is operated for a long period of time, components such as calcium, magnesium, and silica contained in water may be deposited on the opening end of the ejection pipe 8 as the scale 19. It is preferable that the opening area of the opening end is of such a size that the influence of narrowing due to the precipitation of the scale 19 can be substantially ignored.

  FIG. 4 shows an example of a diffuser hole in a conventional apparatus, and illustrates a structure in which a diffuser hole 100 that opens downward is provided on the side surface of the gas pipe 101. Although such a structure is very easy to process, components such as calcium, magnesium, silica, etc. contained in water are deposited around the air diffuser 100 as the scale 102, and pass through the air diffuser 100 from the gas pipe 101. As a result, the flow rate of the oxygen-containing gas supplied to the water decreases, and there is a possibility that the air diffusion holes 100 may be blocked by long-time operation. On the other hand, in the structure shown in FIG. 3, the influence of narrowing due to precipitation of the scale 19 can be avoided with a simple structure by appropriately increasing the opening area of the opening end of the ejection pipe 8. It is possible to ensure the stability of the flow rate of the oxygen-containing gas even when the operation is continued for a long time while suppressing an increase in the manufacturing cost of the apparatus.

FIG. 5 is a line graph showing the opening area distribution of the introduction holes 18 provided in the air diffuser 10. As shown in FIG. 5, the opening area distribution of the introduction hole 18 has two peaks present in the range of range and 170～190Mm ² of 10 to 30 mm ^2, these peaks respectively holes 18a and Hole 18b is shown.

  FIG. 6 is a partial vertical cross-sectional view of the aerobic biological treatment apparatus 1 and shows a state in which the oxygen-containing gas ejected into the water from the diffuser holes 9 through the holes 18 b is supplied into the water as the bubbles 20. In the following, the structure in which the hole 18b as the introduction hole 18 communicates with the main pipe 16 will be described by taking FIG. 6 as an example. However, these explanations are the structures in which the hole 18b communicates with the branch pipe 16. The same applies to. In FIG. 6, the oxygen-containing gas that has flowed into the ejection pipe 8 through the hole 18 b from the main pipe 16 is supplied into the water as bubbles 20 from the opening end of the ejection pipe 8 facing downward, that is, the air diffusion holes 9. When the bubbles 20 rise in the water and reach the biological treatment means 7, surplus sludge adhering to the carrier 6 is peeled off by the vibration and shearing force of the rising bubbles 20, and the peeled sludge passes through the treatment tank 2. It sinks and flows out of the system from the outflow branch pipe 5. Further, as described above, since the carrier 6 is provided with protrusions extending radially from the central portion, the bubbles 20 are refined by the protrusions to become fine bubbles 21 and rise in the biological treatment means 7. As a result, the dissolution of oxygen in water is promoted, and the oxygen-containing gas is sufficiently supplied to the minute gaps in the carrier 6.

  As for the bubbles of oxygen-containing gas ejected into the water from the diffuser holes 9 through the holes 18a having a smaller opening area than the holes 18b, the bubbles are refined by the protrusions provided on the carrier 6 as in the case of the holes 18b. And the dissolution of oxygen in water is promoted.

  FIG. 7 is a bar graph showing the rotation radius distribution of the air holes 9 provided in the air diffuser 10. As shown in FIG. 7, the rotation radius distribution of the air holes 9, that is, the frequency distribution of the number of air holes with respect to the distance (rotation radius) from the rotation axis of the air diffuser 10 to the center of gravity of the opening of the air diffuser 9 is a predetermined pitch. It has peaks that appear repeatedly. According to such a configuration, the oxygen-containing gas ejected from the air diffusion holes 9 is supplied uniformly throughout the biological treatment means 7, and oxygen supply to the biological treatment means 7 and the carrier filled in the biological treatment means 7 are performed. 6 is effectively performed.

  The aerobic biological treatment apparatus according to the present invention is suitable as a factory wastewater treatment apparatus that requires strict cost-related requirements and requires long-term stable operation, and is suitable for food, beverages, pharmaceuticals, chemistry, papermaking, machinery It can be widely applied to wastewater treatment at factories.

DESCRIPTION OF SYMBOLS 1 Aerobic biological treatment apparatus 2 Processing tank 3 Inflow pipe 4 Outflow pipe 5 Outflow branch pipe 6 Carrier 7 Biological treatment means 8 Ejection pipe 9 Air diffuser hole 10 Air diffuser means 11 Conduit 12 Rotating gas supply device 13 Reducer 14 Motor 15 Gas inflow Pipe 16 Main pipe 17 Branch pipe 18 Introduction holes 18a, 18b Hole 19 Scale 20 Bubble 21 Fine bubble 100 Aeration hole 101 Gas pipe 102 Scale

Claims (7)

  A biological treatment means filled with a carrier carrying aerobic microorganisms, and provided around the biological treatment means, around the rotation axis while supplying oxygen-containing gas to the biological treatment means through a plurality of air holes. A rotating aeration means is an aerobic biological treatment apparatus provided in the treatment tank, and the aeration holes are formed by an opening end of an ejection pipe for ejecting the oxygen-containing gas into water, and are generated in the biological treatment means. An aerobic biological treatment apparatus, wherein excess sludge is separated from the carrier by the oxygen-containing gas supplied to the biological treatment means through any of the air holes.   The aerobic biological treatment apparatus according to claim 1, wherein the oxygen-containing gas is supplied into the water downward from the air diffusion holes.   The air diffuser has an introduction hole for introducing an oxygen-containing gas into the ejection pipe, and an opening area of the introduction hole is equal to or less than a flow passage cross-sectional area of the ejection pipe. Aerobic biological treatment equipment.   The aerobic biological treatment apparatus according to claim 3, wherein the opening area distribution of the introduction hole has two or more peaks.   The aerobic biological treatment apparatus according to any one of claims 1 to 4, wherein the air diffuser includes a main pipe extending radially from the rotation shaft and a branch pipe provided by branching from the main pipe. .   The aerobic biological treatment apparatus according to any one of claims 1 to 5, wherein the aeration holes are arranged so that the rotation radius distribution of the aeration holes has a peak that repeatedly appears at a predetermined pitch. The aerobic biological treatment apparatus according to claim 1, wherein the carrier has a plurality of radially extending protrusions.

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