JP5436350B2 - Air lift pump device and sewage treatment facility - Google Patents

Description

  The present invention relates to a pumping pipe installed upright in a treatment tank, an air diffuser that discharges air bubbles to the pumping pipe, and pumps up the water to be treated in the processing tank by an air lift effect due to the air bubbles, and the pumping pipe The present invention relates to an air lift pump device and a sewage treatment facility that include a water supply pipe that is communicated with the water supply pipe and that is disposed horizontally to transfer the water to be treated that has been pumped up to the pumping pipe.

  The sewage treatment facility that purifies sewage including human waste and domestic wastewater is constructed by connecting an anaerobic tank or anaerobic tank and an aerobic tank. The treated water that has been treated flows out into the aerobic tank, and the treated water that has been subjected to the aerobic treatment in the aerobic tank is taken out of the tank through the membrane separator, or flows out into the final sedimentation tank. Furthermore, an air lift pump device is provided for returning a part of the water to be treated in the aerobic tank to the upstream anaerobic tank or anoxic tank together with the sludge.

  In the anaerobic tank, the BOD component contained in the raw water is taken into the anaerobic microorganisms, the phosphorus compound is hydrolyzed and phosphorus is released into the liquid as normal phosphoric acid, and in the anaerobic tank, denitrification treatment is performed. In the aerobic tank, nitrification is performed by aerobic microorganisms, and further, aerobic treatment is performed in which normal phosphoric acid in the water to be treated is taken into sludge.

  In the advanced treatment for removing nitrogen and phosphorus, even if the water to be treated flowing into the sewage treatment facility fluctuates, an anaerobic tank or non-removable tank is used by an air lift pump device to maintain a high treatment efficiency. It is necessary to adjust the amount of water to be treated returned to the oxygen tank to an appropriate amount. Therefore, a technique for accurately measuring the flow rate of water to be treated flowing through the water pipe is required.

  In order to accurately measure the flow rate of water to be treated flowing in a bowl-shaped water channel, a throttle part with a certain shape and size is provided in the middle of the channel to create a flow that is not affected by the downstream water level. A flume type drainage flow meter is known in which a certain relationship is established between the flow rate and the upstream water level, and the flow rate is determined by measuring the water level.

In the flume drainage flow meter, when ha is the upstream water depth (m) and K and m are constants determined by the shape, size, throat width, etc. of the flume, the flow rate Q (m ³ / h) is as follows: It is calculated by a mathematical formula.
Q = K ・ ha ・ m

  Similarly, a weir plate having a certain shape and size is provided in the middle of the water channel to create a flow that is not affected by the downstream water level, and at this time, a constant relationship is established between the flow rate and the upstream water level. Thus, weir-type drainage flowmeters are known that determine the flow rate by measuring the water level.

In a weir-type drainage flow meter using a triangular weir, K is a constant determined by the channel width, notch width, and height to the notch lower edge, and h is a weir head (overflow depth from the notch lower edge of the weir plate) However, in the case of a full width weir, the flow rate Q (m ³ / s) can be obtained by the following formula when the overflow water depth (m) from the upper edge is set.
Q = K ・ h ^5/2・ 1/60

  In Patent Document 1, as an air lift pump device using a weir-type drainage flow meter, a triangular weir that measures circulating water and a return weir that adjusts the amount of circulating water are provided, and it is necessary from the treated water that is excessively pumped from the pumping pipe. An air lift pump device having a distribution metering device for allowing only a circulating water amount to overflow from a triangular weir is disclosed.

  Further, Patent Document 1 discloses an air lift pump device that includes an adjustment valve that adjusts the amount of bubbles released to the pumping pipe and that has a reference line for the circulating water amount formed at the outlet side opening of the water pipe. .

JP-A-11-104664

  However, when measuring the flow rate of the treated water returned by the air lift pump device using the above-described flume type drainage flow meter or weir type drainage flow meter, in order to ensure the water head difference necessary for measurement, It is necessary to pump up to a head difference larger than the head difference required for returning the treated water to the upstream treatment tank, and for that reason, bubbles will be supplied from the air diffuser to the pump pipe with an excessive amount of air diffused. There was a problem of poor energy efficiency.

  Furthermore, in advanced sewage treatment facilities installed in water purification facilities that need to purify a large amount of treated water, large-capacity anaerobic tanks and aerobic tanks composed of concrete frames are constructed, and relatively large airlifts are installed. Since a pump device is installed, installing a weir-type drainage flow meter to measure the flow rate of the return water from the aerobic tank is very large and increases not only the equipment cost but also the power cost of the diffuser. There was also a problem.

  Therefore, for example, as shown in FIG. 7, a pumping pipe 71 arranged upright in the aerobic tank 60, an air diffuser 72 that discharges bubbles toward the pumping pipe 71, and a cover pumped up by the bubbles When the air lift pump device 70 having the substantially horizontal water supply pipe 73 for transferring the treated water from the upper part of the pumping pipe 71 through the partition wall 62 to the anaerobic tank 61 adjacent to the aerobic tank 60 is provided. A flow velocity meter 80 is installed in a bowl-shaped water supply pipe 73 for transferring the treated water pumped up to the vicinity of the water surface of the oxygen tank 61, and an average flow velocity is calculated based on the flow velocity measured by the flow velocity meter 80. It is conceivable to calculate the transfer amount by the product of the average flow velocity and the cross-sectional area through which the water to be treated passes.

  In this case, assuming that the depth from the free water surface to the bottom surface of the bowl-shaped water pipe 73 is 1, the velocimeter 80 is installed at a position where the water depth from the free water surface is 0.6, and the flow velocity measured by the velocimeter 80 is Average flow rate.

  However, when the water level of the treatment tank changes, the water depth at which the velocity meter 80 is installed fluctuates accordingly. Therefore, there is a problem that reliability cannot be ensured for the representative flow velocity of the water pipe 73 calculated.

  In FIG. 8A, when the width of the rectangular water supply pipe 73 is W, and the water level in the water supply pipe 73 is DL when the water level of the treatment tank is the lowest water level LWL, the position of the water depth 0.6DL is shown. An example is shown in which a velocimeter 80 is installed in the apparatus and the flow velocity v measured by the velocimeter 80 is calculated as the average flow velocity v. The flow rate Q (= v × A) is calculated from the product of the average flow velocity v and the passage cross-sectional area A (= DL × W) where the flow meter 50 is installed.

  As shown in FIG. 8B, when the water level of the treatment tank rises to the highest water level HWL, the water depth of the water supply pipe 73 rises to DH. At this time, in order to calculate the average flow velocity, the flow velocity v at the position of the water depth 0.6DH must be measured. However, since the flowmeter 80 is installed at a water depth of 0.6 DL when the water level of the treatment tank is the lowest water level LWL, the flow velocity detected by the flow meter 80 is no longer a value indicating the average flow velocity. .

  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 that can accurately measure the flow rate of water to be treated while reducing facility costs and operation costs.

  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. The upper end height of the pumping pipe is set to a height equal to or lower than the lowest water level of the treatment tank in the region where the water feeding pipe is arranged, and is supplied to the pumping pipe. A deaeration part for opening bubbles to the atmosphere is provided in the water supply pipe, and the downstream side of the deaeration part in the water supply pipe is disposed at a height lower than the lowest water level of the treatment tank, and a velocimeter on the downstream side. Is in the point where is installed.

  According to the above configuration, since the downstream side of the deaeration part of the water supply pipe is arranged at a height lower than the lowest water level of the treatment tank, the water supply pipe on the downstream side of the deaeration part is always filled with the return water. Therefore, according to the anemometer arranged in the downstream portion of such a water pipe, even if the water level of the treatment tank fluctuates, it is possible to always measure the reference velocity for calculating the representative representative velocity. become. In this case, the maximum flow velocity can always be measured as the reference flow velocity by installing an anemometer at the center of the water pipe.

  Further, since the upper end height of the pumping pipe is set to a height equal to or lower than the lowest water level of the treatment tank in the area where the water feeding pipe is disposed, the minimum head required for returning the treated water Therefore, the power required for the air diffuser is minimal, and the extra power required when using a flume-type drainage flow meter to measure the flow rate of the return water. Need not be consumed.

  Furthermore, since the deaeration part that opens the air bubbles supplied to the pumping pipe to the atmosphere is provided in the water pipe arranged horizontally, after the bubbles are sufficiently raised in the water supply pipe, Since it can be opened and the flow through the water supply pipe in a state where a large amount of air bubbles are mixed is eliminated, the flow rate of the return water measured by the anemometer becomes a highly reliable value. In addition, when the degassing part is provided at the upper end of the pumping pipe, the upward flow cannot be efficiently converted into a horizontal flow, and the bubbles are not sufficiently removed by the pumping pipe, and the water to be treated is transported along with a certain amount of bubbles. It is difficult to obtain an accurate value because the flow rate of the return water measured by the anemometer fluctuates due to bubbles.

  In addition to the first feature configuration described above, the second feature configuration is at least the upstream side of the deaeration unit of the water supply pipe at least below the maximum water level of the treatment tank. It is located at a height above the water level.

  According to the above-described configuration, the water to be treated which has been pumped up to the height below the minimum water level of the treatment tank by the pumping pipe is connected to the water pipe arranged below the maximum water level of the treatment tank and above the minimum water level. Therefore, even when the water level of the treatment tank fluctuates, the power required for the air diffuser and the power fluctuation for pumping can be extremely reduced.

  In the third characteristic configuration, as described in the third aspect, in addition to the first or second characteristic configuration described above, the upper pipe wall on the downstream side of the deaeration unit is provided on the upstream side in the water supply pipe. The step portion is formed so as to be lower than the upper tube wall.

  According to the above-described configuration, in the process of flowing from the upstream side of the water pipe toward the deaeration unit, the bubbles mixed in the water to be treated are released and then released to the atmosphere in the deaeration unit. The water to be treated, which can be separated and from which bubbles have been removed, flows from the deaeration part to the downstream side, but there are few bubbles present near the surface of the water to be treated that are not sufficiently deaerated at the deaeration part. Even so, when the water to be treated flows downward from the stepped portion, the water is surely separated from the water to be treated, and an accurate flow rate can be measured more reliably.

  In the fourth feature configuration, as described in claim 4, in addition to any of the first to third feature configurations described above, the cross-sectional area of the water supply pipe on the downstream side of the deaeration unit. Is configured to be smaller than the cross-sectional area on the upstream side of the deaeration part.

  According to the above-described configuration, the flow rate of the water to be treated flowing on the downstream side of the deaeration unit is larger than the flow rate of the water to be treated flowing on the upstream side of the deaeration unit. Accordingly, the air bubbles can be efficiently raised while flowing at a relatively low flow rate on the upstream side of the deaeration unit, and the water to be treated flows in the return pipe at a relatively high flow rate on the downstream side of the deaeration unit. Therefore, the flow velocity can be accurately measured by the anemometer. Moreover, the stirring effect of to-be-processed water can be improved in the processing tank returned by such a comparatively high flow rate.

  In the fifth feature configuration, in addition to any one of the first to third feature configurations described above, the cross-sectional area on the downstream side of the deaeration unit in the water pipe is as described in the fifth aspect. However, it is comprised so that it may become the range of 0.5 to 2 times the cross-sectional area of the upstream of the said deaeration part.

  If the cross-sectional area on the downstream side of the degassing part is about 0.5 times the cross-sectional area on the upstream side of the degassing part, the pressure loss of the water to be treated flowing through the water supply pipe is not so large. Since the water to be treated flows in the return pipe at a relatively high flow velocity, the flow velocity can be accurately measured by the anemometer. In addition, when it is not preferable that the water to be treated in the treatment tank is returned at a relatively high flow rate and the inside of the treatment tank is locally agitated largely, the cross-sectional area on the downstream side of the deaeration part is If it is set to about twice the cross-sectional area on the upstream side, while the treated water is returned for processing relatively slowly, the flow rate is adjusted with an anemometer with an accuracy that does not cause difficulty in adjusting the return amount. It becomes possible to measure.

  In the sixth feature configuration, as described in claim 6, in addition to any of the first to fifth feature configurations described above, the cross-sectional shape of the downstream water supply pipe of the deaeration unit is rectangular. In the point.

  According to the above-described configuration, the water pipe having a rectangular cross-sectional shape is easier to manufacture, so the processing cost is low, and in the case of the same cross-sectional area, the rectangular cross-sectional shape is higher than the circular cross-sectional shape. The vertical dimension can be reduced.

  In addition to any one of the first to sixth feature configurations described above, the seventh feature configuration is based on the flow rate detected by the anemometer from the air diffuser as described in claim 7. It is in the point provided with the control device which adjusts the amount of bubbles supplied.

  According to the above configuration, since the amount of bubbles supplied from the air diffuser can be appropriately adjusted by the control device based on the flow velocity detected by the anemometer, the amount of inflow of the raw water into the treatment tank varies. Even in this case, it is possible to realize advanced processing capable of stably removing nitrogen and phosphorus.

  The characteristic configuration of the sewage treatment facility according to the present invention lies in that an air lift pump device having any one of the first to seventh characteristic configurations described above is provided, as described in claim 8.

  As described above, according to the present invention, it is possible to provide an air lift pump device and a sewage treatment facility that can accurately measure the flow rate of water to be treated while reducing facility costs and operation costs. It was.

Plan view explaining sewage treatment equipment that employs an air lift pump device Sectional drawing explaining the sewage treatment equipment which employ | adopted this air lift pump apparatus Perspective view of air lift pump device Side view of air lift pump device Schematic cross section of the air lift pump device (A) is schematic sectional drawing of the air lift pump apparatus by another embodiment, (b) is schematic sectional drawing of the air lift pump apparatus by another embodiment. Explanatory drawing of an air lift pump device with a flow meter installed in the return pipe It is explanatory drawing of flow velocity distribution in a return pipe, Comprising: (a) is explanatory drawing of flow velocity distribution in case the water level of a processing tank is the lowest water level, (b) is flow velocity in case the water level of a processing tank is the highest water level. Illustration of distribution

  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 FIGS. 1 and 2, the sewage treatment facility 1 is connected to an anaerobic tank 10 into which raw water that is untreated water flows, and an anaerobic microorganism connected to a downstream side of the anaerobic tank 10 via a partition wall 11. The anaerobic tank 20 for denitrifying the water to be treated and the ammonia contained in the water to be treated flowing out of the oxygen-free tank 20 through the partition wall 21 on the downstream side of the oxygen-free tank 20 is nitrified with an aerobic microorganism. An aerobic tank 30 and an air lift pump device 40 for returning a part of the water to be treated nitrified in the aerobic tank 30 to the anoxic tank 20. In addition, the arrow shown with the broken line in FIG. 1,2 represents the flow of to-be-processed water.

  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.

  In the aerobic tank 30, the first region 31 that receives the treated water flowing out from the oxygen-free tank 20 and the second region 32 that guides the treated water flowing in from the first region 31 to the partition wall 21. A separation wall 34 that separates 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 treated water is disposed in the second region 32. A plurality of membrane separation devices 36 for solid-liquid separation 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, but varies. 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.

  Note that the volume of the first region 31 separated by the separation wall 34 is set to be larger than the volume of the second region 32. In particular, it is preferable to form the separation wall 34 so that the volume of the first region 31 is about twice as large as the volume of the second region 32. By comprising in this way, an aerobic process is favorably performed in the 1st area | region 31. FIG.

  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.

  Since the water to be treated that has been subjected to the aerobic treatment in the first region 31 is configured to flow in a U shape from the open portion on the other end side of the separation wall 34 toward the second region 32, The turbulent flow of the water to be treated due to the interference between the flow of air diffused from the air device 35 and the flow of air diffused from the air diffuser 38 does not occur.

  As shown in FIG. 3 to FIG. 5, the air lift pump device 40 includes a pumping pipe 41 having a rectangular cross section that is erected and disposed in 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. 5, 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 secured, and there is no need 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 right angles.

  The water supply pipe 43 is provided with a deaeration unit 44 for releasing bubbles supplied to the pumping pipe 41 to the atmosphere. The bubbles released by the diffuser pipe 42 are degassed from the water to be treated by the deaeration unit 44, and the bubbles supplied from the diffuser are not returned to the anoxic tank 20 as they are. It is possible to avoid the occurrence of an unfavorable situation in which the concentration of dissolved oxygen increases and the denitrification efficiency decreases.

  Thus, by providing the deaeration unit 44 in the middle of the water supply pipe 43, while the air bubbles diffused for pumping the water to be treated flow through the water supply pipe 43 in the water supply pipe 41, It is possible to efficiently deaerate by gathering on the upper tube wall 43b by the deaeration part 44. In addition, if a deaeration part is provided immediately above the pumping pipe 41, the water to be treated is transferred to the water pipe 43 without being sufficiently deaerated, which is not preferable.

  A flowmeter 50 is installed on the downstream side of the deaeration unit 44 in the water supply pipe 43, and the flow rate of the water to be treated is calculated based on the flow velocity detected by the flowmeter 50, so that bubbles from the air diffuser 42 are removed. A control device 51 for adjusting the supply amount to control the flow rate of the water to be treated to the target value is provided.

  If the flow rate is measured in a state in which a large amount of bubbles diffused by the air diffuser 42 are contained in the treated water pumped by the pumping pipe 41, an accurate flow rate cannot be detected, and the circulation amount of the treated water appropriately. May not be adjusted. Therefore, a flow meter 50 is installed in the water supply pipe 43 on the downstream side of the deaeration unit 44 so that the flow rate of the water to be treated after deaeration is accurately measured.

  If the amount of treated water transferred from the aerobic tank 30 to the anaerobic tank 20 is large, excess air will be brought into the anoxic tank 30, the dissolved oxygen concentration will increase, the denitrification efficiency will decrease, and conversely If the amount of treated water transferred is small, the amount of denitrification decreases due to a decrease in the amount of treated water circulating. Therefore, the control device 51 adjusts the amount of bubbles supplied to the diffuser to appropriately adjust the amount of water to be treated.

  If the height of the water supply pipe 43 on the downstream side of the deaeration unit 44 is H and the width is W, the velocimeter 50 is arranged at the center of the height H of the water supply pipe 43 and at the center of the width W. Therefore, the maximum flow velocity can be measured regardless of whether the flow of water to be treated flowing in the water supply pipe 43 is a laminar flow or a turbulent flow. Further, the velocimeter 50 is arranged at a position about 10H away from the inlet of the water supply pipe 43 on the downstream side of the deaeration unit 44. This is preferable in that the water to be treated flowing in the water supply pipe 43 is stabilized. Even if the water supply pipe 43 on the downstream side of the deaeration unit 44 cannot be configured long due to conditions such as the size of the treatment tank, the velocimeter 50 is connected to the water supply pipe 43 on the downstream side of the deaeration unit 44 from the entrance. It is preferable to arrange at a position separated by about 3H.

  The lower pipe wall 43a at least upstream of the deaeration unit 44 in the water supply pipe 43 is disposed at a height lower than the lowest water level LWL of the aerobic tank 30, and at least downstream of the deaeration unit 44 in the water supply pipe 43. Is arranged at a height lower than the lowest water level LWL of the anaerobic tank 20. Therefore, the water supply pipe 43 on the downstream side of the deaeration unit 44 in which the anemometer 50 is installed is always installed below the surface of the water regardless of the fluctuation of the water level in the anaerobic tank 20, and the water supply pipe 43 is treated with water to be treated. Since it is satisfied, the flow velocity can be measured with high accuracy.

  It is preferable that at least the upstream side of the deaeration unit 44 in the water supply pipe 43 is disposed at a height equal to or lower than the highest water level HWL of the treatment tank and equal to or higher than the lowest water level LWL. This is because even if the water level of the treatment tank fluctuates, the power required for the air diffuser and the power fluctuation for pumping can be extremely reduced.

  The upper pipe wall 43 b on the upstream side of the deaeration unit 44 in the water supply pipe 43 is configured by an inclined surface that is inclined upward toward the downstream side so that the height gradually increases toward the deaeration unit 44. Accordingly, the bubbles released by the air diffuser 42 and rising in the pumping pipe 41 rise to the water surface in the water supply pipe 43 and are released to the atmosphere by the deaeration unit 44 along the upper pipe wall 43b formed of an inclined surface. Therefore, the air bubbles that have finished the role of pumping up by the pumping pipe 41 can be quickly separated upward in the water supply pipe 43 in a horizontal posture.

  The upper pipe wall 43d and the lower pipe wall 43c on the downstream side of the deaeration part 44 in the water supply pipe 43 are downstream so that the height gradually decreases from the deaeration part 44 to the upper pipe wall 43d and the lower pipe wall 43c. It is comprised by the inclined surfaces 47b and 47a which incline below toward the side.

  Further, the upper pipe wall 43d on the downstream side of the deaeration unit 44 is lower than the minimum height of the upper pipe wall 43b of the water feed pipe 43 communicated with the water feed pipe 43 through the curved pipe 46 from the pumping pipe 41. A stepped portion is formed so that

  The stepped portion is realized by a part of the inclined surface 47b described above, and bubbles mixed in the water to be treated rise to the water surface in the process in which the water to be treated flows from the upstream side of the water supply pipe 43 toward the deaeration unit 44. Then, since the air is released to the atmosphere at the deaeration part, it is possible to efficiently separate the bubbles from the water to be treated as compared with the case where the deaeration part is provided immediately above the pumping pipe 41.

  Furthermore, when the water to be treated from which bubbles have been removed flows from the deaeration unit 44 to the water supply pipe 43 on the downstream side, the deaeration unit 44 is not sufficiently deaerated, and there are a few bubbles near the surface of the water to be treated. Even when there is water, when the water to be treated flows down to the downstream water supply pipe 43 located below the stepped portion, bubbles are reliably separated from the water to be treated at the stepped portion. It becomes possible to measure the accurate flow rate.

  The air diffuser 42a is connected to a blower via an air pipe. The air supplied from the blower is discharged as fine bubbles from the air diffuser 42a. The fine bubbles preferably have a size of φ2 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.

  The diffuser 42a of the diffuser 42 shown in FIGS. 3, 4, and 5 is a tube-shaped membrane-type diffuser tube, and the diffuser tube located on the outermost side below the lower opening of the pumped pipe is the lower opening of the pumped pipe. Four diffuser tubes are distributed and arranged at equal intervals so as to be in the vicinity of one side of 41a vertically below.

  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, the unevenness of the water to be treated and the flow of bubbles in the pumping pipe is preferably 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. In addition, the control device 51 is provided with a display unit that displays a flow rate calculated based on the flow rate of the water to be treated detected by the anemometer 50.

  The operator visually checks the return flow rate of the water to be treated displayed on the display unit, operates the volume so that the flow rate becomes the target flow rate, adjusts the rotation speed of the blower, and Adjust the air supply rate.

  The control device 51 includes a feedback control mechanism that automatically adjusts the rotation speed of the blower so as to control the calculated return flow rate of the treated water to the target flow rate, without being limited to the configuration in which the operator manually operates the volume. Also good.

  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 path 43, that is, shortening the total head, it is possible to reduce the amount of aeration necessary for water supply of the water to be treated, that is, the power of the blower. Moreover, since it can prevent that the to-be-processed water with high dissolved oxygen concentration flows into the anoxic tank 20 by reducing the amount of aeration, the possibility of reducing the denitrification efficiency of the anoxic tank 20 can be reduced. .

  Furthermore, part 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.

  With the above configuration, the power of the air lift pump device 40 required for returning from the aerobic tank 30 to the anoxic tank 20 can be reduced, and the water to be treated can be efficiently transferred.

Next, another embodiment according to the present invention will be described.
As shown in FIG. 6A, the upper pipe wall 43d on the downstream side of the deaeration unit 44 in the water supply pipe 43 is disposed at a height lower than the lowest water level LWL of the treatment tank (oxygen-free tank 30). For example, the upper pipe wall 43b on the upstream side of the deaeration unit 44 in the water supply pipe 43 may be disposed at a height higher than the lowest water level LWL of the aerobic tank 30 and lower than the highest water level HWL. It may be installed at a position higher than the water pipe 43.

  Moreover, as shown in FIG.6 (b), 43 d of upper side pipe walls of the downstream of the deaeration part 44 among the water supply pipes 43 are arrange | positioned in the height lower than the minimum water level LWL of a processing tank (anoxic tank 30). If so, the upper pipe wall 43 b on the upstream side of the deaeration unit 44 in the water supply pipe 43 may be disposed at a position higher than the highest water level HWL of the aerobic tank 30. In addition, the deaeration unit 44 does not necessarily have an inclined surface. Furthermore, the lower pipe wall 43a of the water supply pipe 43 upstream from the deaeration unit 44 and the lower pipe wall 43c of the downstream water supply pipe 43 may be set at the same height.

  In the water supply pipe 43, the cross-sectional area on the downstream side of the deaeration unit 44 is preferably configured to be smaller than the cross-sectional area on the upstream side of the deaeration unit 44. The flow rate of the water to be treated flowing on the downstream side of the deaeration unit 44 is larger than the flow rate of the water to be treated flowing on the upstream side of the deaeration unit 44. Accordingly, the air bubbles can be efficiently raised while flowing at a relatively low flow rate on the upstream side of the deaeration unit, and the water to be treated flows in the return pipe at a relatively high flow rate on the downstream side of the deaeration unit. Therefore, the flow velocity can be accurately measured by the anemometer. Moreover, the stirring effect of to-be-processed water can be improved in the processing tank returned by such a comparatively high flow rate.

  Further, in the water supply pipe 43, the cross-sectional area on the downstream side of the deaeration unit 44 is preferably configured to be in the range of 0.5 to 2 times the cross-sectional area on the upstream side of the deaeration unit 44. . If the cross-sectional area on the downstream side of the degassing part is about 0.5 times the cross-sectional area on the upstream side of the degassing part, the pressure loss of the water to be treated flowing through the water supply pipe is not so large. Since the water to be treated flows in the return pipe at a relatively high flow velocity, the flow velocity can be accurately measured by the anemometer. In addition, when it is not preferable that the water to be treated in the treatment tank is returned at a relatively high flow rate and the inside of the treatment tank is locally agitated largely, the cross-sectional area on the downstream side of the deaeration part is If it is set to about twice the cross-sectional area on the upstream side, while the treated water is returned for processing relatively slowly, the flow rate is adjusted with an anemometer with an accuracy that does not cause difficulty in adjusting the return amount. It becomes possible to measure.

  In embodiment mentioned above, the air lift pump apparatus 40 which returns the to-be-processed water in the 2nd area | region 32 to the anaerobic tank 20, and the water supply path 23 which returns the to-be-processed water in the anoxic tank 20 to the anaerobic tank 10 are provided. However, the water to be treated in the oxygen-free tank 20 may be returned to the anaerobic tank 10 by the air lift pump device 40 instead of the water supply path 23. 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. From the viewpoint of processing efficiency, it is preferable to set the return water amount from the machine tank 30 to the anaerobic tank 20 to 3q and the return water amount from the anaerobic tank 20 to the anaerobic tank 10 to q with respect to the inflow amount q.

  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 discharge port 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.

  Furthermore, the air lift pump device according to the present invention is not limited to a case where it is provided in a sludge treatment facility that employs a membrane separation type activated sludge method, and a nitrification liquid circulation activated sludge method or a biological circulation type anaerobic method that does not employ a membrane separation type activated sludge method It can be applied as a pump device when water to be treated is transferred from one treatment tank installed through a partition wall to sludge treatment equipment, flow rate adjustment tank, sewage septic tank, etc. adopting the aerobic method Further, there is no limitation on the type of water to be transferred, the transfer source, and the transfer destination.

  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 facility 10: Anaerobic tank 11: Partition 12: Communication port 20: Anoxic tank 21: Partition 22: Communication port 23: Water supply channel 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 41a: Lower opening 42: Air diffuser 42a: Air diffuser 43: Water pipe 43a: Lower pipe wall 43b: Upper pipe wall 43c: Lower pipe wall 43d: Upper pipe wall 44: Deaeration part 45: Deposition part 46: Curved pipe 47: Step part 47a: Lower pipe wall 47b: Upper pipe wall 50: Current meter 51: Control device

Claims (8)

A pumping pipe installed 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,
The upper end height of the pumping pipe is set to a height equal to or lower than the lowest water level of the treatment tank in the region where the water feeding pipe is arranged, and a deaeration unit that opens the bubbles supplied to the pumping pipe to the atmosphere is the water feeding pipe. An air lift pump device in which a downstream side of the deaeration unit in the water supply pipe is disposed at a height lower than the lowest water level of the processing tank, and a current meter is installed on the downstream side.   2. The air lift pump device according to claim 1, wherein at least an upstream side of the deaeration unit in the water supply pipe is disposed at a height equal to or lower than a maximum water level of the processing tank and equal to or higher than a minimum water level.   The air lift pump device according to claim 1 or 2, wherein a stepped portion is formed in the water supply pipe so that an upper pipe wall on the downstream side of the deaeration part is lower than an upper pipe wall on the upstream side.   The air lift pump according to any one of claims 1 to 3, wherein a cross-sectional area on the downstream side of the deaeration part in the water supply pipe is configured to be smaller than a cross-sectional area on the upstream side of the deaeration part. apparatus.   The cross-sectional area of the downstream of the deaeration part among the said water supply pipes is comprised so that it may become the range of 0.5 to 2 times the cross-sectional area of the upstream of the said deaeration part. The air lift pump device according to any one of the above.   The air lift pump device according to any one of claims 1 to 5, wherein a cross-sectional shape of a downstream water supply pipe of the deaeration unit is rectangular.   The air lift pump device according to any one of claims 1 to 6, further comprising a control device that adjusts a supply amount of bubbles from the air diffuser based on a flow velocity detected by the anemometer.   A sewage treatment facility comprising the air lift pump device according to any one of claims 1 to 7.

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