JP2012000584A - Air lift pump apparatus and wastewater treatment facility - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air lift pump apparatus dissolving such inconvenience that bubbles are spread on a liquid surface and deposited thickly in a treatment tank which is the transfer destination of water to be treated.SOLUTION: The air lift pump apparatus 40 includes: a pumping pipe 41 erected in an aerobic tank 30; an air diffuser 42 for discharging bubbles to the pumping pipe 41 and pumping the water to be treated inside the air diffuser 30; a water supply pipe 43 communicated with the pumping pipe 41 and horizontally arranged so as to horizontally transfer the water to be treated which is pumped by the pumping pipe 41; a separation wall 48 which is arranged so as to face the flow of the water to be treated supplied by the water supply pipe 43, and which separates the bubbles from the water to be treated by drifting the water to be treated; and a deaeration part 44 which is disposed upstream from the separation wall 48 and which releases the bubbles contained in the water to be treated to the atmosphere.

Description

  The present invention relates to a pumping pipe installed upright in a treatment tank, an air diffuser for discharging bubbles into the pumping pipe and pumping up water to be treated in the treatment tank, and a pumping pipe connected to the pumping pipe. The present invention relates to an air lift pump device and a sewage treatment facility provided with a water pipe arranged horizontally to transfer the water to be treated.

  A sewage treatment facility that purifies sewage including human waste and domestic wastewater is constructed so that an anaerobic tank or an anaerobic tank and an aerobic tank are connected via a partition wall that divides each tank. A part of the water to be treated that has been anaerobically treated in the oxygen tank is configured to flow out from the flow path formed in the partition wall to the aerobic tank. The water to be treated which has been aerobically treated in the aerobic tank is taken out of the tank through the membrane separator, or flows out to the final sedimentation basin, and the water to be treated which has been subjected to precipitation filtration is taken out to the outside.

  An air lift pump device is installed to return part of the water to be treated in the aerobic tank to the upstream anaerobic tank or anoxic tank together with sludge.

  Patent Document 1 discloses a wastewater treatment apparatus provided with such an air lift pump device. The wastewater treatment apparatus includes a suction pipe extending in the vertical direction, a discharge pipe extending in the horizontal direction from the suction pipe, and an air supply means for supplying air into the suction pipe, and the air supply means operates. In this way, an air lift pump device for transferring the object to be transferred through the suction pipe and the discharge pipe is installed, and in order to reduce the air supply amount, the discharge pipe is disposed below the lower limit water level in the region where the discharge pipe extends.

  Patent Document 2 discloses a sewage treatment tank in which an air lift pump device for transferring the water to be treated in the anaerobic filter bed tank to the carrier fluid biological filtration tank is installed. A cap member that disperses the water to be treated is provided as a defoaming device at the discharge portion of the transfer pipe that transports the water to be treated by the air lift pump device. When falling water is supplied from the upper surface of the liquid level of the tank, foaming at the liquid interface is physically suppressed.

JP 2004-330003 A Japanese Patent Laid-Open No. 2002-1009

  However, depending on the properties of the water to be treated that is transferred by the air lift pump device, the water to be treated is foamed by the bubbles supplied from the air diffuser, and the foamed state is maintained in the treatment tank at the transfer destination and diffused to the liquid level. As a result, there is a problem that a thick layer is deposited, and a layer of accumulated bubbles overflows around the treatment tank, and that a bad odor is generated from the foamed water to be treated.

  For example, in the air lift pump device disclosed in Patent Document 1, a discharge pipe extending in the horizontal direction and arranged below the lower limit water level is connected to an upper part of a suction pipe extending in the vertical direction, and the suction pipe Although the upper end of the water is opened to the atmosphere and functions as a deaeration unit that discharges bubbles to the atmosphere, if the water to be treated is easily foamed, the deaeration unit cannot sufficiently deaerate the The bubbles are transferred together with the treated water, and the foam layer deposited on the liquid surface is pushed up from below by the bubbles transferred together with the water to be treated, and overflows outside the tank.

  In addition, the defoaming device described in Patent Document 2 is a structure for suppressing foaming when the water to be treated falls onto the liquid surface of the transfer destination treatment tank, and the foamed water to be treated is removed. It is not intended to foam, and if bubbles accumulate in the transfer pipe, there is a problem that the air lift effect due to the bubbles supplied from the air diffuser does not occur and the water to be treated cannot be pumped up.

  In view of the above-described problems, an object of the present invention is to provide an air lift pump device and a sewage treatment facility capable of eliminating the disadvantage that bubbles are diffused and accumulated thickly in a liquid surface in a treatment tank to which water to be treated is transferred. Is to provide

  In order to achieve the above-described object, the characteristic configuration of the air lift pump device according to the present invention is as described in claim 1 of the present invention, and includes a pumping pipe installed upright in a treatment tank, and bubbles in the pumping pipe. An air diffuser that discharges and pumps up the water to be treated in the treatment tank, and a water pipe that communicates with the pumping pipe and is disposed horizontally to transfer the water to be treated that has been pumped up to the pumping pipe in the horizontal direction. An air lift pump device comprising: a separation wall that is disposed to face a flow of water to be treated that is fed by the water pipe, and that separates bubbles from the water to be treated by drifting the water to be treated. And a deaeration unit that is installed on the upstream side of the separation wall and opens the bubbles contained in the water to be treated to the atmosphere.

  According to the above-described configuration, the flow of the water to be treated fed by the water pipe is drifted by the separation wall, and bubbles are effectively separated from the water to be treated at the time of the drift. The bubbles separated by the separation wall are quickly defoamed and degassed by the deaeration section provided upstream, effectively eliminating the situation where the foaming state diffuses beyond the separation wall. can do. In order to separate the bubbles by giving resistance to the flow of the water to be treated, the separation wall is preferably arranged in a substantially vertical posture or an inclined posture in which the upper end is inclined to the downstream side. Is drifted below the separation wall, and the separated bubbles rise upward along the separation wall and come into contact with the atmosphere to be defoamed.

  In the second feature configuration, as described in claim 2, in addition to the first feature configuration described above, the separation wall is disposed downstream of the discharge port of the water pipe, and the discharge port And a guide wall that allows outflow of the water to be treated and prevents the outflow to the side between the separation wall and the separation wall.

  According to the above-described configuration, the water to be treated transferred in a foamed state through the water supply pipe is drifted by the separation wall, and bubbles are effectively separated from the water to be treated at the time of the drift, and the deaeration provided on the upstream side thereof Defoamed quickly at the part. At this time, since the flow is blocked by the separation wall and the guide wall, the diffusion of the foamed layer on the liquid surface of the transfer destination treatment tank is effectively prevented. Then, the water to be treated from which the bubbles are separated flows into the tank from the lower opening of the region where the side is partitioned by the separation wall and the guide wall, and the separated bubbles are the regions where the side is partitioned by the separation wall and the guide wall Is deposited in the upper space of the water and defoamed in contact with the atmosphere.

  In addition to the second feature configuration described above, the third feature configuration is formed so that the upper ends of the separation wall and the guide wall protrude above the water surface of the treatment tank. In addition, the projecting portion is formed with an opening through which part of the foamed water to be treated can flow out.

  According to the above-described configuration, even when the foam layer deposited in the upper space opened to the atmosphere in the region partitioned by the separation wall and the guide wall does not quickly disappear, it seems to protrude above the water surface of the treatment tank. The foamed layer is confined in the area defined by the upper end of the separation wall and the guide wall arranged in, and the foam can be removed over time, and the foamed layer diffuses and overflows on the water surface of the treatment tank. Can be effectively avoided. Further, when the thickness of the foam layer is increased, a part of the foam layer flows out from the opening formed in the protruding portion, so that a large amount of the foam layer diffuses to the water surface of the treatment tank at a time. Can also be eliminated.

  The fourth characteristic configuration is that, in addition to the first characteristic configuration described above, the deaeration part is provided in the water supply pipe as described in the fourth aspect.

  According to the above-described configuration, the water to be treated transferred in a foamed state through the water supply pipe is drifted by the separation wall, and bubbles are effectively separated from the water to be treated at the time of the drift, and the upstream water pipe is provided. It is quickly defoamed in the deaeration part. If the separation wall is placed opposite to the outlet of the water pipe and the upper and lower surfaces of the outlet of the water pipe are notched, the water to be treated will flow into the treatment tank from the notch on the lower surface of the outlet of the water pipe, It becomes possible to deaerate from the notch on the upper and lower surfaces of the outlet of the water pipe.

  In the fifth feature configuration, as described in claim 5, in addition to the first feature configuration described above, the water pipe is installed such that the posture is changed from a horizontal posture to an inclined posture downward, The separation wall is constituted by the inclined pipe wall of the water supply pipe.

  The separation wall that separates the water to be treated for gas-liquid separation may be provided in the water supply pipe itself, not necessarily disposed downstream of the outlet of the water supply pipe. That is, the inclined pipe wall of the water supply pipe whose posture is changed from the horizontal posture to the downward inclined posture may function as a separation wall for causing the water to be treated to drift and separating the gas and liquid.

  The sixth feature configuration is that, in addition to the fifth feature configuration described above, the deaeration part is provided in the immediate vicinity of the upstream side of the inclined pipe wall.

  According to the above-described configuration, the bubbles separated by the inclined tube wall are defoamed and degassed from the water to be treated by the deaeration unit provided in the immediate vicinity of the upstream side.

  In the seventh feature configuration, in addition to the fifth or sixth feature configuration described above, in addition to the fifth or sixth feature configuration described above, a treatment tank in which the pumping pipe is arranged and a discharge port of the water supply pipe are arranged. A partition wall that partitions the processing tank is formed in a Y-shaped cross section, and the inclined portion tube wall is disposed along the inclined portion of the partition wall.

  In the treatment tank in which the partition wall is formed in a Y-shaped cross section, a space in which piping is arranged is formed in the widened portion on the upper side of the partition wall, and when the water supply pipe is disposed horizontally above the partition wall, There is a disadvantage that a lift higher than that required for pumping up to the surface of the tank is required, and the power of the blower fan connected to the diffuser increases. In addition, it is difficult to install a water supply pipe in the widened portion on the upper side of the partition wall that is a piping space. Therefore, when installing a water pipe below the widened part of the partition wall, the water pipe that feeds the treated water pumped up to the vicinity of the water surface of the treatment tank by the pump pipe from the vicinity of the water surface to the inclined part of the partition wall. If it is arranged so as to be inclined obliquely downward along, it is possible to easily realize the separation wall constituted by the above-mentioned inclined portion tube wall by this inclined portion, and the power of the blower fan is not required more than necessary. The water pipe can be installed easily.

  In the eighth feature configuration, in addition to any one of the first to seventh feature configurations described above, the defoaming means for defoaming the bubbles accumulated in the deaeration unit is provided. In the point which is arrange | positioned at the said deaeration part.

  When the bubbles that have accumulated in the deaeration part are slowly defoamed slowly, the bubbles may overflow from the deaeration part. Can be degassed. In addition, as a defoaming means, a water spray mechanism for spraying treated water or treated water to the foam layer, or a plurality of defoaming porous plates and meshes or a plurality of defoam projections on the foam layer. With a plate-like body, a structure that applies a physical force to some of the bubbles that are foamed by the surface tension of the water to be treated, and a structure that chemically defoams using an antifoaming agent. Can be adopted.

  The characteristic configuration of the sewage treatment facility according to the present invention is that, as described in claim 9, the air lift pump device having any one of the first to eighth characteristic configurations described above is provided.

  As described above, according to the present invention, there is provided an air lift pump device and sewage treatment equipment that can eliminate the disadvantage that bubbles are diffused and accumulated on the liquid surface in a treatment tank to which water to be treated is transferred. I was able to do that.

The top view of the sewage treatment equipment which employ | adopted the air lift pump apparatus by this invention Sectional drawing of the sewage treatment equipment which employ | adopted the air lift pump apparatus by this invention Perspective view of air lift pump device Side sectional view of the air lift pump device The perspective view of the air lift pump apparatus by another embodiment The perspective view of the air lift pump apparatus by another embodiment Explanatory drawing of the sewage treatment facility which employ | adopted the air lift pump apparatus by another embodiment. Explanatory drawing of the sewage treatment facility which employ | adopted the air lift pump apparatus by another embodiment. Schematic plan view of a sewage treatment facility employing an air lift pump device according to another embodiment Schematic plan view of a sewage treatment facility employing an air lift pump device according to another embodiment

  Hereinafter, the case where the air lift pump apparatus by this invention is applied as a pump apparatus which returns the to-be-processed water in the aerobic tank of a sewage treatment facility to an anoxic tank is demonstrated.

  As shown in FIG. 1 and FIG. 2, a sewage treatment facility 1 capable of advanced treatment that purifies domestic wastewater by dephosphorization and denitrification includes an anaerobic tank 10 into which raw water that is untreated water flows. The anaerobic tank 10 is connected to the downstream side of the anaerobic tank 10 via the partition wall 11, and is disposed through the partition wall 21 on the downstream side of the anaerobic tank 20. The aerobic tank 30 for nitrifying ammonia contained in the water to be treated flowing out of the anaerobic tank 20 with an aerobic microorganism, and a part of the water to be treated nitrified in the aerobic tank 30 are returned to the anoxic tank 20. An air lift pump device 40 is provided.

  Each processing tank is configured by, for example, placing concrete in a recess formed by excavation in the ground, and arrows indicated by broken lines in FIGS. 1 and 2 represent the flow of water to be treated.

  In the anaerobic tank 10, anaerobic treatment is performed by microorganisms under anaerobic conditions, and BOD components contained in the raw water are taken into the microorganisms, and phosphorus compounds are hydrolyzed to release phosphorus as normal phosphoric acid into the liquid. The water to be treated that has been anaerobically treated in the anaerobic tank 10 is transferred to the anoxic tank 20 through the communication port 12 formed in the lower part of the partition wall 11.

  In the anaerobic tank 20, anaerobic treatment is performed by microorganisms under anaerobic conditions, and denitrification treatment, that is, reduction treatment of nitrate ions and nitrite ions to nitrogen gas is performed. The water to be treated that has been anaerobically treated in the anaerobic tank 20 is transferred to the aerobic tank 30 through the communication port 22 formed in the lower part of the partition wall 21.

  Water to be treated is supplied to the aerobic tank 30 into a first region 31 that receives the water to be treated flowing out of the oxygen-free tank 20 and a second region 32 that guides the water to be treated flowing from the first region 31 to the partition wall 21. A separation wall 34 for separating the aerobic tank 30 along the outflow direction is provided, and a plurality of air diffusers 35 that diffuse the treated water in the first region 31 are installed, and the second region 32 is treated. A plurality of membrane separation devices 36 for solid-liquid separation of water are installed, and an air lift pump device 40 is installed downstream of the second region 32. The separation wall 34 is configured by a substantially vertical wall whose upper edge protrudes above the water surface, the base end side is joined to the partition wall 21, and the other end side is opened in the aerobic tank 30.

  In the first region 31, nitrification treatment is performed in which ammonium ions derived from human urine and the like contained in the water to be treated are oxidized by microorganisms and converted into nitrous acid and nitric acid under aerobic conditions due to aeration from the aeration device 35. In addition, an aerobic treatment is performed in which normal phosphoric acid in the water to be treated is taken into sludge and accumulated as polyphosphoric acid.

  In the second region 32, solid matter such as activated sludge is separated from the water to be treated by the membrane separation device 36, and the separated water to be treated is discharged to a treated water tank (not shown) in the subsequent stage through a water pipe 37. . Note that the amount of raw water that is untreated water that flows into the anaerobic tank 10 is not constant and varies, but the membrane separation device 36 is configured so that the water level of each treatment tank is equal to or higher than a predetermined minimum water level LWL by a control unit (not shown). However, the discharge amount is adjusted so as to be equal to or lower than the maximum water level HWL.

  As the separation membrane used in the membrane separation device 36, an ultrafiltration membrane, a microfiltration membrane or the like is preferably employed. As the form of the membrane, a hollow fiber membrane, a flat membrane, a tubular membrane or the like is preferably employed.

  An air diffuser 38 for removing and cleaning sludge adhering to the membrane surface of each membrane separator 36 is disposed below the plurality of membrane separators 36. In the second region 32, nitrification is performed by activated sludge under aerobic conditions with air supplied from the air diffuser 38. The activated sludge in the second region 32 is discharged as excess sludge through the extraction pipe 39.

  As shown in FIG. 3 and FIG. 4, the air lift pump device 40 includes a pumping pipe 41 having a rectangular cross-section standing on an aerobic tank 30 as a processing tank, and a lower opening formed at the lower end of the pumping pipe 41. It is arranged to face the lower side of 41a and discharges bubbles toward the lower opening 41a, thereby communicating with the air diffuser 42 for pumping up the treated water in the aerobic tank 30, and the pumping pipe 41, and the pumping pipe A water supply pipe 43 having a rectangular cross section is provided so as to transfer the treated water pumped by 41 in the horizontal direction and return it to the anaerobic tank 20 adjacent to the aerobic tank 30. In FIG. 4, broken line arrows represent the flow of water to be treated and bubbles.

  The pumping pipe 41 is supported by a gantry 45 disposed at the bottom of the treatment tank. When the treatment tank has a ceiling, the pumping pipe 41 and the water supply pipe 43 may be supported by a support unit suspended from the ceiling.

  The air diffuser 42 includes a plurality of air diffusers 42a dispersed and arranged on the same plane in order to release the fine bubbles substantially uniformly in a range that is approximately equal to the area of the lower opening 41a. The air part 42 a is disposed in parallel with the surface of the lower opening 41 a of the water pump 41.

  The upper end height of the pumping pipe 41 is set to a height equal to or lower than the lowest water level LWL of the aerobic tank 30, and the pumping pipe 41 and the water feeding pipe 43 are communicated with each other through a curved pipe 46. Therefore, a smooth flow can be ensured, and it is not necessary to set the driving power of the air diffuser 42 high so as to compensate for the pressure loss that occurs when the water pipe 43 communicates with the upper end of the water pump pipe 41 at a right angle.

  On the downstream side of the discharge port 43b of the water supply pipe 43, a separation wall is arranged so as to face the flow of the water to be treated fed by the water feed pipe 43 and separates the bubbles from the water to be treated by drifting the water to be treated. 48 is installed.

  Between the discharge port 43b of the water supply pipe 43 and the separation wall 48, a guide wall 48a that allows outflow of the water to be treated and prevents the outflow to the side is disposed. The upper ends of the separation wall 48 and the guide wall 48 a are formed so as to protrude upward from the water surface of the oxygen-free tank 20, and the lower ends are formed so as to protrude downward from the bottom of the water supply pipe 43. An opening 48b through which a part of the foamed water to be treated can flow out is formed in the protrusion. On the upstream side of the separation wall 48, a deaeration unit 44 that opens air bubbles contained in the water to be treated to the atmosphere is installed. The horizontal length of the guide wall 48a may be appropriately set according to the amount of bubbles in the region partitioned by the separation wall 48 and the guide wall 48a.

  The upper pipe wall 43a of the water supply pipe 43 is arranged on the downstream side so that the height gradually increases toward the deaeration part 44 so as to continue to the upper end of the guide wall 48a formed so as to protrude above the water surface of the anoxic tank 20. It is comprised by the inclined surface which inclines upwards.

  By configuring as described above, the flow of the water to be treated fed by the water feeding pipe 43 is drifted by the separation wall 48, and the bubbles are effectively separated from the water to be treated at the time of the drift. Then, the bubbles separated by the separation wall 48 are quickly defoamed and deaerated by the deaeration unit 44 provided on the upstream side.

  At this time, since the flow of bubbles is blocked by the separation wall 48 and the guide wall 48a, it is effective to prevent the foam layer from diffusing across the liquid level of the anoxic tank 20 beyond the separation wall 48 and the guide wall 48a. Can be prevented. Then, the water to be treated from which the bubbles are separated flows into the tank through the lower opening 48c of the region partitioned by the separation wall 48 and the guide wall 48a, and the separated bubbles are separated from the separation wall 48 and the guide wall by the sides. Deposited in the upper space of the area partitioned by 48a, defoamed in contact with the atmosphere.

  The separation wall 48 provides a resistance to the flow of the water to be treated and separates the bubbles. Therefore, the separation wall 48 is preferably arranged in a substantially vertical posture or an inclined posture in which the upper end is inclined to the downstream side. The water is drifted below the separation wall, and the separated bubbles rise upward along the separation wall and come into contact with the atmosphere to be defoamed. The degree of inclination of the separation wall 48 is appropriately set according to the degree of generation of bubbles. In addition, the separation wall 48 is not limited to a flat plate shape, and may have a shape curved vertically or horizontally with respect to the direction of the water to be treated.

  Furthermore, since the upper ends of the separation wall 48 and the guide wall 48a are formed so as to protrude above the water surface of the anoxic tank 20, the upper space opened to the atmosphere in the region partitioned by the separation wall 48 and the guide wall 48a is formed. Even if the deposited foam layer does not quickly defoam, the foam layer is confined in the region defined by the separation wall 48 and the upper end of the guide wall 48a arranged so as to protrude above the water surface of the treatment tank. The defoaming can be performed over time, and the situation where the foamed layer diffuses and overflows on the water surface of the anoxic tank 20 can be effectively avoided.

  Further, since the separation wall 48 and the guide wall 48b are formed to extend downward from the bottom of the water supply pipe 43, the air bubbles separated by the separation wall 48 and separated into gas and liquid together with the water to be treated are added to the oxygen-free tank 20. It is possible to reduce the risk of flowing into the inside.

  Further, when the thickness of the foam layer increases, a part of the foam layer flows out from the opening 48d formed in the projecting portion, so that a large amount of the foam layer diffuses to the water surface of the anoxic tank 20 at one time. Such inconvenience can be solved.

  Note that the opening 48a is not limited to a configuration having four rectangular openings, and an appropriate number of circular or polygonal shapes may be formed. Further, a part of the upper end of the guide wall 48a may be cut away so that the foamed layer overflows to the water surface of the anoxic tank 20, and is confined in a region defined by the separation wall 48 and the upper end of the guide wall 48a. It suffices if a part of the foamed layer is formed so as to gradually flow out.

  Further, as shown in FIG. 4, a defoaming mechanism 49 is provided in the upper space of the deaeration unit 44 as defoaming means for defoaming bubbles generated on the water surface of the deaeration unit 44. The defoaming mechanism 49 pumps up the water to be treated in the oxygen-free tank 20 or supplies clean water by a pump mechanism installed inside or outside the tank of the oxygen-free tank 20. It is composed of a sprinkling mechanism that sprinkles water toward the bubbles generated on the water surface.

  When the speed at which bubbles accumulated in the deaeration unit 44 naturally defoam is slow, the bubbles may overflow from the deaeration unit 44 into the anoxic tank 20, but even in such a case, the defoaming mechanism By providing 49, the deaeration part 44 can efficiently deaerate. In addition, as the defoaming mechanism 49, it is preferable to employ a physical mechanism that applies a physical force to some of the bubbles foamed by the surface tension of the water to be treated to defoam. For example, a sprinkling mechanism for spraying treated water or treated water to the foam layer, or a plate-like body having a plurality of defoaming porous plates or meshes or a plurality of defoaming projections on the foam layer. It can be realized by providing. Further, the defoaming mechanism 49 is not limited to the configuration for defoaming the entire surface of the deaeration unit 44, and may be configured to defoam only a part of the deaeration unit 44.

  In addition, as shown in FIG. 5, you may comprise an air lift pump apparatus, without making the lower end of the separation wall 48 and the guide wall 48a protrude below the pipe bottom of the water supply pipe 43. As shown in FIG. In addition, the thickness of the foam layer does not become too large with respect to the height of the upper ends of the separation wall 48 and the guide wall 48b, and the foam layer is sufficiently removed in the region defined by the upper ends of the separation wall 48 and the guide wall 48a. When foaming is possible, the opening 48d may not be formed in the guide wall 48a. When the flow rate of the water to be treated discharged from the discharge port 43b of the water supply pipe 43 is slow, the bubbles that are drifted by the separation wall 48 and separated into gas and liquid are unlikely to flow into the anoxic tank 20 together with the water to be treated. Because.

  Furthermore, as shown in FIG. 6, the air lift pump device may be configured by providing a separation wall 48 instead of the guide wall 48 a on the downstream side of the water supply pipe 43.

  Even in such a configuration, the flow of the water to be treated fed by the water feeding pipe 43 is drifted by the separation wall 48, and bubbles are effectively separated from the water to be treated at the time of the drift. The bubbles separated by the separation wall 48 are quickly defoamed and degassed by the deaeration unit 44 provided on the upstream side thereof, so that the situation where the foamed state diffuses beyond the separation wall 48 is effective. Can be eliminated.

  The diffuser 42a of the diffuser 42 shown in FIGS. 3 to 6 is a tube-shaped membrane-type diffuser pipe, and the diffuser pipe located on the outermost side below the lower opening of the pumped pipe is the lower opening 41a of the pumped pipe. Four diffuser tubes are distributed at equal intervals so as to be in the vicinity of one side vertically below, and are connected to a blower (not shown) via the air supply tube. The air supplied from the blower is discharged as fine bubbles from the air diffuser 42a. For example, the size of the fine bubbles is preferably 2 mm or less.

  A membrane-type air diffuser that discharges air bubbles from holes or slits formed through a flexible tube or sheet having flexibility or elasticity as an air diffuser that can discharge bubbles containing a lot of fine bubbles of φ2 mm or less at a low cost, A diffuser type diffuser that discharges air bubbles from a porous plate such as ceramic can be employed.

  Further, a coarse bubble diffusing tube may be used as the diffusing portion of the diffusing device 42. For example, a coarse bubble diffusing tube having a hole diameter of about φ5 to 20 mm can be used.

  In this way, if the plurality of diffuser portions 42a are dispersed and arranged at intervals, the flow of the water to be treated that rises in the pumping pipe through the diffuser portions 42a from below the diffuser portion 42a is induced. Therefore, it is preferable in that the unevenness of the water to be treated and the flow of bubbles in the pumping pipe is reduced.

  The air lift pump device 40 includes an adjustment volume for adjusting the supply amount of bubbles discharged from the air diffusion device 42 according to the rotation speed of the blower in order to adjust the pumping amount of the water to be treated. A mechanism is provided. The air diffusion amount adjusting mechanism may be configured by a valve provided in the middle of a path from the blower to the air diffusion part 21a.

  Then, for example, the rotation speed of the blower is set so as to increase or decrease the amount of treated water returned from the second region 32 (aerobic tank 30) to the anoxic tank 20 in proportion to the increase or decrease of the inflow amount of raw water. By increasing or decreasing the amount, the sewage treatment can be performed stably.

  The water to be treated that has been nitrified in the aerobic tank 30 is returned to the upstream side of the anoxic tank 20 by the air lift pump device 40 configured as described above. As a result, nitrate ions and nitrite ions contained in the water to be treated are circulated to the anaerobic tank 20 by the nitrification treatment of the aerobic tank 30 to perform the denitrification treatment.

  By disposing the air lift pump device 40 in the vicinity of the partition wall 21 and shortening the water supply passage 43, that is, shortening the total head, reducing the amount of air required for water supply of the water to be treated, that is, the power of the blower. In addition, the amount of bubbles generated in the deaeration unit 44 can be reduced by reducing the amount of air diffused.

  A portion of the water to be treated returned to the anoxic tank 20 via the air lift pump device 40 is returned to the anaerobic tank 10 via the water supply path 23. Microorganisms in the membrane separation tank 30 having taken in phosphorus are circulated to the anaerobic tank 10 through the water supply channel 23, and phosphorus is released into the liquid as normal phosphoric acid.

  Since the water to be treated containing activated sludge is returned from the aerobic tank 30 to the anaerobic tank 20 and the water to be treated is returned from the anoxic tank 20 to the anaerobic tank 10, The water to be treated which is denitrified and does not contain nitrate nitrogen and nitrite nitrogen and consumes oxygen is returned to the anaerobic tank 10, and the NOx and oxygen-free conditions that are the conditions for releasing phosphorus in the anaerobic tank 10 Can be maintained.

  Therefore, in the anaerobic tank 10, the phosphorus compound is efficiently released as normal phosphoric acid, and the released normal phosphoric acid is taken into the activated sludge more than the amount released in the anaerobic tank 10 in the subsequent aerobic tank 30, It becomes possible to remove phosphorus from treated water to a high degree.

  Although not described in detail in the above-described embodiment, the anaerobic tank 10 and the oxygen-free tank 20 are provided with a stirring mechanism that stirs the water to be treated so that each process is performed uniformly.

  In the above-described embodiment, the air lift pump device 40 that returns the treated water in the second region 32 to the anoxic tank 20 and the water supply path 23 that returns the treated water in the anoxic tank 20 to the anaerobic tank 10. Although the structure provided with was demonstrated, you may comprise so that the to-be-processed water of the anoxic tank 20 may be returned to the anaerobic tank 10 with the air lift pump apparatus 40 instead of the water supply path 23. FIG. Moreover, you may comprise so that the to-be-processed water of the 2nd area | region 32 sent with the one air lift pump apparatus 40 may be returned to each of the anaerobic tank 20 and the anaerobic tank 10 by predetermined amount. It is preferable from the viewpoint of processing efficiency that the amount of water returned from the machine tank 30 to the anaerobic tank 20 is 3Q and the amount of water returned from the anaerobic tank 20 to the anaerobic tank 10 is Q with respect to the inflow amount Q.

  With the above configuration, it is possible to provide an air lift pump device that can eliminate the inconvenience of bubbles being diffused and accumulated thickly in the liquid surface in the treatment tank to which the water to be treated is transferred.

Next, another embodiment according to the present invention will be described.
As shown in FIGS. 7 and 8, when the partition wall 60 that partitions the anaerobic tank 20 and the aerobic tank 30 as a processing tank is formed in a Y-shaped cross section, the widened portion on the upper side of the partition wall 60 When a space for arranging the pipe 61 and the like is formed in the pipe, and the water pipe of the air lift pump device is disposed horizontally above the partition wall 60, a head higher than the head required for pumping up to the water surface of the treatment tank is required. There arises a disadvantage that the power of the blower fan connected to the air diffuser 52 is increased. It is also difficult to install a water supply pipe in the widened portion 62 on the upper side of the partition wall 60 that is a piping space.

  Therefore, the air lift pump device 50 that returns the treated water from the adjacent aerobic tank 30 to the anoxic tank 20 through the partition wall 60 having a Y-shaped section as described above will be described.

  The air lift pump device 50 is disposed to face a lower side of a lifting pipe 51 having a rectangular cross-section that is erected and disposed in an aerobic tank 30 as a processing tank, and a lower opening 51a formed at the lower end of the lifting pipe 51, By discharging bubbles toward the lower opening 51a, the diffuser 52 for pumping up the water to be treated in the aerobic tank 30 and the pumping pipe 51 are connected to the pumping water 51, and the water to be treated pumped up to the pumping pipe 51 is horizontal. It is provided with a water supply pipe 53 having a rectangular cross section that is horizontally disposed so as to be transferred in the direction and returned to the anaerobic tank 20 adjacent to the aerobic tank 30. In FIG. 8, broken line arrows represent the flow of water to be treated and bubbles.

  The pumping pipe 51 is supported by a pedestal 55 disposed at the bottom of the treatment tank. When the treatment tank has a ceiling, the pumping pipe 51 and the water supply pipe 53 may be supported by a support unit suspended from the ceiling.

  The air diffuser 52 includes a plurality of air diffusers 52a distributed on the same plane in order to discharge the fine bubbles substantially uniformly in an area that is approximately equal to the area of the lower opening 51a. The air part 52 a is arranged in parallel with the surface of the lower opening 51 a of the water pump 51.

  The upper end height of the pumping pipe 51 is set to a height equal to or lower than the lowest water level LWL of the aerobic tank 30, and the pumping pipe 51 and the water feeding pipe 53 are communicated with each other via a curved pipe 56. Therefore, a smooth flow can be ensured, and there is no need to set the driving power of the air diffuser 52 high so as to compensate for the pressure loss that occurs when the water pipe 53 communicates with the upper end of the water pump pipe 51 at right angles.

  The water supply pipe 53 includes a horizontal water supply pipe 53a, a water supply pipe 53b connected to the downstream side of the water supply pipe 53a and inclined downward toward the downstream side, and a horizontal posture of the water supply pipe 53b connected to the downstream side of the water supply pipe 53b. It consists of a water pipe 53c. The treated water in the aerobic tank 30 that has been pumped is discharged to the anoxic tank 20 from the discharge port 53d of the water supply pipe 53c.

  The lower pipe wall 70 of the horizontal water supply pipe 53a is disposed at a height lower than the lowest water level LWL of the aerobic tank 30, and the upper pipe wall 53e is inclined upward so that the height gradually increases toward the downstream side. An inclined surface 71 is used. The upper end is disposed at a height higher than the highest water level HWL of the aerobic tank 30 and is open to the atmosphere.

  The upper pipe wall 72 and the lower pipe wall 73 of the water supply pipe 53b are configured by inclined surfaces that are inclined downward from the boundary with the water supply pipe 53a toward the downstream side. The upper pipe wall 74 of the water pipe 53c is disposed at a position lower than the lower pipe wall 70 of the water pipe 53a, and the water pipe 53c passes through a narrow portion below the widened portion 62 on the upper side of the partition wall 60. To be arranged.

  The upper pipe wall 72, which is the inclined pipe wall of the water supply pipe 53b, is arranged along the inclined part 63 of the partition wall 60, and functions as a separation wall 58 that separates the water to be treated and separates the gas and liquid. The bubbles separated by the separation wall 58 are defoamed and degassed from the water to be treated by the deaeration unit 54 provided in the immediate vicinity of the upstream side. That is, the separation wall 58 and the deaeration unit 54 that separates the water to be treated for gas-liquid separation are provided in the water supply pipe 53 itself.

  Further, a defoaming mechanism 49 for defoaming bubbles generated on the water surface of the deaeration unit 54 is provided in the space above the deaeration unit 54. The defoaming mechanism 49 pumps up the water to be treated in the oxygen-free tank 20 or supplies the treated water by a pump mechanism installed inside or outside the tank of the oxygen-free tank 20 to remove the deaeration unit 54. It is composed of a sprinkling mechanism that sprinkles water toward the bubbles generated on the water surface. If the bubbles that have accumulated in the deaeration unit 54 are slowly defoamed slowly, the bubbles may overflow from the deaeration unit 54 into the aerobic tank 30. Even in such a case, the defoaming mechanism By providing 49, the deaeration unit 54 can efficiently deaerate. In addition, as the defoaming mechanism 49, it is preferable to employ a physical mechanism that applies a physical force to some of the bubbles foamed by the surface tension of the water to be treated to defoam. For example, a sprinkling mechanism for spraying treated water or treated water to the foam layer, or a plate-like body having a plurality of defoaming porous plates or meshes or a plurality of defoaming projections on the foam layer. It can be realized by providing. Further, the defoaming mechanism 49 is not limited to the configuration for defoaming the entire surface of the deaeration unit 54, and may be configured to defoam only a part of the deaeration unit 54.

  As described above, when the water supply pipe 53 is installed below the widened portion 62 in the partition wall 60, the water supply pipe 53 for supplying the treated water pumped up to the vicinity of the water surface of the aerobic tank 30 by the pumping pipe 51 is provided on the water surface. By arranging to be inclined obliquely downward along the inclined portion 63 of the partition wall 61 from the vicinity, a separation wall can be easily realized by the upper tube wall 72 as the inclined portion tube wall described above. The power of the blower fan is not required more than necessary, and the water supply pipe 53 can be easily installed.

Next, still another embodiment according to the present invention will be described.
In the above-described embodiment, the structure in which the water supply pipe of the air lift pump device is disposed horizontally through the partition wall 21 that partitions the anaerobic tank 20 adjacent to the aerobic tank 30 has been described. The water pipe does not necessarily have to be arranged horizontally through the partition wall 21.

  For example, as shown in FIG. 9, the pumping pipe 61 and the air diffuser 52 of the air lift pump device 60 are arranged in the aerobic tank 30, and the water supply pipe 63 is placed outside the aerobic tank 30 and the anaerobic tank 20. The structure which arrange | positions and arrange | positions and arrange | positions the discharge port 63a of the water pipe 63 in the tank of the anoxic tank 20 may be sufficient. Even in such an air lift pump device 60, it is disposed on the downstream side of the discharge port 63a so as to face the flow of the water to be treated fed by the water pipe, and the water to be treated drifts away from the water to be treated. If the separation wall 68 for separating the bubbles is provided, the same effects as those of the above-described embodiment can be obtained. In FIG. 9, broken line arrows represent the flow of water to be treated and bubbles. FIG. 9 is a schematic diagram, and illustrations of the anaerobic tank 10, the air diffuser 35, the membrane separator 36, and the like are omitted.

  Further, in addition to or instead of the separation wall 68, a defoaming mechanism 69 for defoaming bubbles generated on the water surface of the deaeration unit 64 may be provided. The defoaming mechanism 69 pumps up the water to be treated in the oxygen-free tank 20 by a pump mechanism installed inside or outside the oxygen-free tank 20 toward the bubbles generated on the water surface of the deaeration unit 64. It consists of a watering mechanism that sprinkles water. The watering device as the defoaming mechanism 69 preferably sprays water in a direction to prevent bubbles accumulated in the deaeration unit 54 from spreading over the entire water surface of the anoxic tank 20.

  In the above-described embodiment, the configuration including the separation wall on the downstream side of the water supply pipe 63 has been described. However, as illustrated in FIG. 10, even if the configuration includes only the defoaming mechanism 69 without including the separation wall 68. The defoaming mechanism 69 may be arranged in multiple. In FIG. 10, broken line arrows represent the flow of water to be treated and bubbles. FIG. 10 is a schematic diagram, and the description of the anaerobic tank 10, the air diffuser 35, the membrane separator 36, and the like is omitted.

  In the above-described embodiment, the configuration in which the defoaming means defoams by physical means like the defoaming mechanism constituted by the watering mechanism has been described. However, the defoaming means is a chemical means using an antifoaming agent. The structure which defoams the foam which generate | occur | produced on the liquid level by may be sufficient. An example of such an antifoaming agent is a silicone-based antifoaming agent.

  In any of the embodiments described above, the water pipe may be installed so that the lower pipe wall of the water pipe is below the water level of the treatment tank.

  In the above-described embodiment, the case where the air lift pump device is configured by a rectangular pumping pipe and a water feeding pipe has been described. However, the pumping pipe and the water feeding pipe are not limited to a rectangular shape, and may be a round pipe. Further, the shape of the lower opening and the outlet of the water to be treated may be a bell mouth shape.

  In the above-described embodiment, the material of the pumping pipe and the water supply pipe constituting the air lift pump device was not specified, but depending on the property of the water to be treated in the treatment tank in which the air lift pump device according to the present invention is installed, chemical resistance, corrosion resistance An appropriate material may be used in consideration of the properties and the like.

  In the above-described embodiment, the air lift pump device according to the present invention returns a part of the water to be treated in the machine tank of the sludge treatment facility adopting the membrane separation type activated sludge method equipped with the membrane separation device to the anoxic tank. However, it may be installed so that a part of the water to be treated in the oxygen-free tank is returned to the anaerobic tank.

  According to the airlift pump device of the present invention, in a large-scale sewage treatment facility, particularly a sewage treatment plant as a large-scale sewage treatment facility that employs a membrane separation activated sludge method, the amount of return of treated water is large. The amount of air diffused by the air diffuser provided in the pump device is larger than the amount of air diffused by the air diffuser provided in the air lift pump device of a small septic tank employing carrier flow biological filtration. Whereas the concentration is about 2000 mg / L, the membrane separation activated sludge method employed in a large sewage treatment facility has a high MLSS concentration of, for example, 8000 to 15000 mg / L (average of about 10000 mg / L), and the return water Bubbles are likely to be generated on the water surface of anaerobic tanks and oxygen-free tanks, which are the return destinations, so it is possible to reduce the risk of contamination of the processing tanks due to bubbles. .

  Each of the above-described embodiments is an example of the present invention, and the present invention is not limited by the description. The specific configuration of each part can be appropriately changed and designed within the range where the effects of the present invention are exhibited. Needless to say.

1: Sewage treatment equipment 10: Anaerobic tank 11: Partition wall 12: Communication port 20: Anoxic tank 21: Partition wall 22: Communication port 23: Water pipe 30: Aerobic tank 31: First region 32: Second region 34 : Separation wall 35: Air diffuser 36: Membrane separator 37: Water supply pipe 38: Air diffuser 39: Extraction pipe 40: Air lift pump device 41: Water pump 41 a: Lower opening 42: Air diffuser 42 a: Air diffuser 43 : Water supply pipe 43a: enlarged portion 43b: bowl-shaped water supply pipe 43c upper end 44: deaeration part 45: mount 46: curved pipe 47: air supply pipe 48: separation wall 48a: opening 49: defoaming mechanism

Claims (9)

A pumping pipe arranged upright in the treatment tank, an air diffuser that discharges air bubbles to the pumping pipe to pump up the water to be treated in the treatment tank, communicated with the pumping pipe, and pumped to the pumping pipe. An air lift pump device provided with a water pipe arranged horizontally to transfer the treated water in the horizontal direction,
A separation wall that is disposed so as to face the flow of the water to be treated fed by the water pipe, and separates bubbles from the water to be treated by drifting the water to be treated;
An air lift pump device comprising a deaeration unit that is installed on the upstream side of the separation wall and opens air bubbles contained in the water to be treated to the atmosphere.   The separation wall is installed on the downstream side of the discharge port of the water supply pipe, and allows outflow of water to be treated between the discharge port and the separation wall. The air lift pump device according to claim 1, wherein a guide wall for blocking is arranged.   The upper end of the separation wall and the guide wall is formed so as to protrude above the water surface of the treatment tank, and an opening through which a part of the foamed water to be treated flows out is formed in the protrusion. 2. The air lift pump device according to 2.   The air lift pump device according to claim 1, wherein the deaeration unit is provided in the water supply pipe.   2. The air lift pump device according to claim 1, wherein the water supply pipe is installed so that the posture is changed from a horizontal posture to a downward inclined posture, and the separation wall is configured by an inclined pipe wall of the water supply pipe.   The air lift pump device according to claim 5, wherein the deaeration part is provided in the immediate vicinity of the upstream side of the inclined part pipe wall.   A partition wall that partitions the treatment tank in which the pumping pipe is disposed and the treatment tank in which the discharge port of the water supply pipe is disposed is formed in a Y-shaped cross section, and the inclined tube wall is formed in the inclined portion of the partition wall. The air lift pump apparatus of Claim 5 or 6 arrange | positioned along.   The air lift pump device according to any one of claims 1 to 7, wherein a defoaming means for defoaming bubbles accumulated in the deaeration unit is disposed in the deaeration unit.   A sewage treatment facility comprising the air lift pump device according to any one of claims 1 to 8.

Images