JP2011000555A - Wastewater treatment facility and method of rebuilding the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wastewater treatment facility which can reduce power of a pump mechanism necessary for returning water to be treated from an aerobic tank to an anoxic tank to perform efficient treatment.SOLUTION: A separation wall 34 which separates the aerobic tank 30 into a first area 31 receiving the water to be treated flowing in from the anoxic tank 20 and a second area 32 introducing the water to be treated flowing in from the first area 31 to a partition wall along the inflow direction of the water to be treated is provided in the aerobic tank 30. An air diffuser 35 for diffusing air into the water to be treated is installed in at least either one of the first area 31 and the second area 32, and the pump mechanism 40 is provided downstream of the second area 32. The pump mechanism 40 comprises a lifting pipe 41 disposed in the vicinity of the partition wall 21, an air diffuser 42 for supplying air bubbles into the lifting pipe 41, and an air lift pump 44 provided with a water passage 43 for transferring the water to be treated, lifted by the air bubbles, from the upper part of the lifting pipe 41 to the upstream side of the anoxic tank 20.

Description

  The present invention is an anaerobic tank for denitrifying treated water by anaerobic microorganisms, and ammonia contained in the treated water flowing from the oxygen-free tank is nitrified with an aerobic microorganism. The present invention relates to a sewage treatment facility equipped with an aerobic tank, a sewage treatment facility equipped with a pump mechanism for returning a part of water to be treated nitrified in the aerobic tub to an anoxic tank, and a method for remodeling the sewage treatment facility.

  Conventionally, as a method of removing organic substances contained in the sewage water to be treated, a diffuser installed in the reaction tank by flowing the supernatant water from which dust and sand were removed in the first sedimentation basin into the reaction tank While mixing and agitating the water to be treated and supplying oxygen, the organic sludge is decomposed with activated sludge, and the water to be treated with the organic substance decomposed is allowed to flow into the final sedimentation basin to precipitate the activated sludge. The standard activated sludge method for purifying treated water is widely used.

Such a standard activated sludge method is vulnerable to load fluctuations and has problems such as a relatively low removal rate of nitrogen and phosphorus. In recent years, the standard activated sludge method has been biologically desorbed to improve the denitrification performance. An anaerobic tank and biological denitrification treatment for the standard activated sludge method for the purpose of removing the BOD component of the nitrification solution circulation method incorporating the nitrogen treatment, the BOD component removal of the standard activated sludge method, filamentous bulking measures, and the dephosphorization performance An example in which an incorporated biological circulation type anaerobic aerobic method (A ₂ O method) is employed is increasing.

  For example, as shown in FIG. 12, Patent Document 1 includes an anaerobic tank 70 and an aerobic tank 72 containing a microorganism-immobilized carrier 71, and a part of the water to be treated which is treated in the aerobic tank 72. A sewage treatment facility that employs a nitrification liquid circulation activated sludge method that includes a circulation path 73 that circulates the gas to the anoxic tank 70 has been proposed.

  Further, as shown in FIG. 13, Patent Document 2 discloses a filtration device 80 that solid-liquid separates suspended substances in inflowing water, an anaerobic tank 81 that introduces filtered water from the filtration device 80, and An aerobic tank 82 for introducing the mixed liquid from the anaerobic tank 81, a circulation means 83 for circulating a part of the mixed liquid in the aerobic tank 82 to the anaerobic tank 81, and a mixed liquid from the aerobic tank 82. A solid-liquid separation device 84 for solid-liquid separation into treated water and sludge, a sludge refining tank 85 for introducing sludge from the filtration device 80 for refining, and a separation liquid from the sludge refining tank 85 for introducing the separation liquid, In addition, a sewage treatment facility that employs a biocirculation anaerobic aerobic method that includes an anaerobic tank 86 that introduces part of the separated sludge from the solid-liquid separator 84, and the effluent of the anaerobic tank 86 is introduced into the anoxic tank 81. Has been proposed.

  In addition, in a sewage treatment facility that adopts the standard activated sludge method, the nitrification solution circulating activated sludge method, and the biological circulation type anaerobic aerobic method, the final sedimentation basin is used to separate the treated sludge discharged from the aerobic tank and the activated sludge. However, since the separation efficiency in the final sedimentation basin is greatly influenced by the properties of the activated sludge, there is a problem that much labor is spent on maintaining the sludge sedimentation in a good state at all times. Therefore, a sewage treatment facility provided with a membrane separation tank in which a membrane separation device is installed on the downstream side of the aerobic tank has also been proposed.

JP 2002-263687 A JP 2000-93992 A

  In the sewage treatment facility that employs the above-described nitrification liquid circulation activated sludge method, in order to improve the denitrification efficiency in the anaerobic tank, the water to be treated in which the nitrification reaction is sufficiently performed in the aerobic tank 72 In order to return to 70, water to be treated is sucked from a suction pipe 74 installed on the most downstream side of the aerobic tank 72 by a mechanical land pump 75 installed outside the tank or a submersible pump installed inside the tank. In addition, a pump mechanism for returning to the upstream side of the anaerobic tank 70 via the long circulation path 73 was provided.

  Similarly, even in a sewage treatment facility that employs a biological circulation type anaerobic aerobic method, in order to improve the denitrification efficiency in the anaerobic tank 81, there is no treated water that has undergone sufficient nitrification reaction in the aerobic tank 82. In order to return to the oxygen tank 81, a pump mechanism was provided for sucking in water to be treated from the most downstream side of the aerobic tank 82 and returning it to the upstream side of the anaerobic tank 81 via the long circulation means 83.

  However, the head required to return the treated water from the aerobic tank to the oxygen-free tank is relatively low, and there is no mechanical pump that can handle such a low head. When the water to be treated is returned from the most downstream side of the aerobic tank to the upstream side of the anaerobic tank through a long circulation path, the total head is increased due to an increase in piping resistance, etc. In combination with the rise, there was a problem of consuming more power than necessary, and there was a problem that the number of parts increased, such as installing a valve for adjusting the amount of water supply in the return pipe.

  In addition, in any sewage treatment facility, when multiple treatment paths for treated water with anaerobic tank and aerobic tank are arranged in parallel, the installation space for the piping is limited. The water to be treated is sucked through the branch pipe from the most downstream side of each aerobic tank by a single on-site pump installed in the aerobic tank, and then sent to the upstream side of the anaerobic tank with one merging pipe. As a result of being returned to each anaerobic tank after mixing the water to be treated with a different degree of aerobic treatment for each treatment path in the merging pipe, There is also a problem that the purification process varies in each processing path, and the purification process efficiency may be reduced.

  Therefore, a pump mechanism using an air lift pump may be installed in place of the mechanical pump for the purpose of reducing pump power and piping space.

  However, when returning the treated water from the most downstream side of the aerobic tank to the upstream side of the anaerobic tank using an air lift pump via the long circulation path, the total head rises due to an increase in piping resistance, etc. The amount of aeration required to return a predetermined amount of treated water increases, and as a result, the treated water having a high dissolved oxygen concentration is returned to the anoxic tank, and the denitrification efficiency in the anoxic tank is improved. There was a problem that there was a risk of reduction.

  Further, even in the sewage treatment facility provided with the above-described membrane separation tank, it is necessary to return the treated water from the most downstream side of the membrane separation tank to the upstream side of the anoxic tank through a long circulation path. There was a problem.

  In view of the above-described problems, an object of the present invention is to provide a sewage treatment facility capable of reducing the power of a pump mechanism necessary for returning from an aerobic tank to an anoxic tank and performing an efficient treatment.

  In order to achieve the above-mentioned object, the first characteristic configuration of the sewage treatment facility according to the present invention is that, as described in claim 1 of the claims, a plurality of treatment tanks for purifying treated water by microorganisms have partition walls. A sewage treatment facility having a pump mechanism for returning a part of the water to be treated to the downstream treatment tank to the upstream treatment tank, the upstream treatment tank being connected to the downstream treatment tank. Separation wall that separates the downstream treatment tank into a first region that receives the treated water flowing from the tank and a second region that guides the treated water flowing from the first region to the partition wall of the upstream treatment tank. Provided with a pump mechanism at least near the partition wall of the second region, the pump mechanism being pumped by the bubbles, a pumping pipe disposed near the partition wall, an air diffuser for supplying bubbles to the pumping pipe, and Treatment where treated water is arranged upstream from the upper part of the pumping pipe In that it is constituted by an air lift pump having a feed water channel to transfer to.

  According to the above-described configuration, the water to be treated flowing from the upstream treatment tank to the downstream treatment tank flows into the first region, and the most downstream side of the second region in contact with the partition wall with the upstream treatment tank. It is returned to the anoxic tank by the pump mechanism installed in the. In this way, the water to be treated is returned to the anoxic tank by the pump mechanism installed on the most downstream side of the second region, so that the piping that becomes the return path of the water to be treated can be shortened and the structure can be simplified. Therefore, the power of the pump mechanism necessary for returning the treated water can be reduced.

  Furthermore, since the pump mechanism is composed of an air lift pump, the power required to feed the water to be treated can be greatly reduced as compared with a pump mechanism using a mechanical pump. The air lift pump is a mechanical pump. Since it can be manufactured at a lower cost, the initial cost can be reduced. In particular, a power source (aeration device) for pumping water can be provided below the surface of the water, which is effective when employed in facilities where space on the surface of the water is limited.

  As described in claim 2, the second characteristic configuration is arranged through an anaerobic tank for denitrifying treated water by anaerobic microorganisms, an anoxic tank and a partition wall, and flows from the anoxic tank. This is a sewage treatment facility equipped with an aerobic tank that nitrifies ammonia contained in the water to be treated with aerobic microorganisms and a pump mechanism that returns a portion of the water to be treated nitrified in the aerobic tank to the anoxic tank. The separation wall that separates the aerobic tank into the aerobic tank into the first region that receives the water to be treated flowing from the oxygen-free tank and the second region that guides the water to be treated flowing from the first region to the partition wall And an air diffuser that diffuses the water to be treated in at least one of the first region and the second region, and a pump mechanism is provided on the downstream side of the second region. A pumping pipe arranged in the vicinity, a diffuser for supplying bubbles to the pumping pipe, Ri is a pumping been treated water from the top of the riser pipe in that they are constituted by the air lift pump equipped with feed water channel to transfer to the anoxic tank.

  According to the above-described configuration, the water to be treated flowing from the anaerobic tank to the aerobic tank flows into the first region, and is diffused by the diffuser provided at least in either the first region or the second region. Thus, a part of the water to be treated is returned to the anoxic tank by a pump mechanism installed on the most downstream side of the second region in contact with the partition wall with the anoxic tank. In this way, the water to be treated is returned to the anoxic tank by the pump mechanism installed on the most downstream side of the second region, so that the piping that becomes the return path of the water to be treated can be shortened and the structure can be simplified. Therefore, the power of the pump mechanism necessary for returning the treated water can be reduced.

  In addition, for example, even when a plurality of treatment paths for anaerobic tanks and aerobic tanks are arranged in parallel, water to be treated in each aerobic tank is supplied to each pump mechanism, that is, each aerobic tank. The air lift pump mechanism is installed at a low cost and does not require installation space on the surface of the water, and is returned to each anaerobic tank and purified independently through the treatment path of each anaerobic tank and aerobic tank. Compared with the case of using a large-powered onshore pumping mechanism in which return water from a plurality of oxygen-free tanks is mixed and then separated and returned in each oxygen-free tank, In addition, the power cost can be significantly reduced without lowering the purification efficiency.

  Furthermore, since the pump mechanism is composed of an air lift pump, the power required to feed the water to be treated can be greatly reduced as compared with a pump mechanism using a mechanical pump. The air lift pump is a mechanical pump. Since it can be manufactured at a lower cost, the initial cost can be reduced. In particular, a power source (aeration device) for pumping water can be provided below the surface of the water, which is effective when employed in facilities where space on the surface of the water is limited.

  In addition, since the path for returning a part of the treated water nitrified in the aerobic tank to the anaerobic tank can be configured short, the amount of air diffused to the air lift pump corresponding to the return amount of the treated water can be reduced. Oxygen contained in the treated water that has been returned can avoid as much as possible the occurrence of an unfavorable situation in which the concentration of dissolved oxygen in the anoxic tank is increased and the denitrification reaction is lowered.

  In addition to the second feature configuration described above, the third feature configuration is installed in the first region with an air diffuser that diffuses the water to be treated. A membrane separator for solid-liquid separation of water to be treated is installed.

  According to the above configuration, the water to be treated is nitrified by the air diffuser that diffuses the water to be treated provided in the first region, and further, the membrane separation device is provided in the second region, thereby managing sludge. However, the sludge in the aerobic tank can be maintained at a high concentration, and since there is no need for a final sedimentation tank, there are advantages such as a compact facility.

  The fourth feature configuration is set so that, in addition to the third feature configuration described above, the volume of the first region separated by the separation wall is larger than the volume of the second region, as described in claim 4. It is in the point.

  According to the above-described configuration, by setting the volume of the first area larger than the volume of the second area, sufficient aerobic treatment can be performed in the first area even when the volume of the aerobic tank is limited. It can be carried out.

  In the fifth feature configuration, as described in claim 5, in addition to the third or fourth feature configuration described above, two separation walls for separating the aerobic tank along the inflow direction of the water to be treated are provided. The second region is provided between the pair of first regions.

  According to the above configuration, the water to be treated flows from the anoxic tank into each of the first regions sandwiching the second region, and the water to be treated that has been nitrified in the first region is installed in the second region. A part of the water to be treated is returned to the anaerobic tank by the air lift pump installed at the most downstream side of the second area in contact with the partition wall with the oxygen-free tank.

  The filtration membrane provided in the membrane separation device installed in the second region needs to be pulled out of the upper tank from the tank during maintenance such as cleaning. However, in the existing sewage treatment facilities that adopt the standard activated sludge method, the nitrification liquid circulation activated sludge method, and the biological circulation type anaerobic aerobic method, for example, installation of worker passages, air supply pipes to the diffuser, etc. Because of the space, the top surface often extends from the upper side wall of each processing tank toward the center of each tank upper space. In such a case, when the second region is disposed in contact with the side wall, when the filtration membrane is pulled upward, there is a possibility of interfering with the extended top surface.

  Even in such a case, if a membrane separation device is installed in the second region formed between the pair of first regions, the filtration membrane can be pulled upward and maintained without interfering with the top surface. Become.

  In the sixth feature configuration, in addition to any of the second to fifth feature configurations described above, the BOD component contained in the water to be treated is added upstream of the oxygen-free tank. The anaerobic tank to be removed is continuously connected via the partition wall, and the water to be treated in the aerobic tank is returned to the anaerobic tank via the air lift pump, and a part is returned to the anaerobic tank. In the point.

  According to the above-described configuration, the water to be treated that is denitrified in the anaerobic tank and does not contain nitrate nitrogen and nitrite nitrogen and consumes oxygen is returned to the anaerobic tank. Release conditions of NOx and oxygen-free are maintained. As a result, the phosphorus compound is efficiently released as normal phosphoric acid in the anaerobic tank, and the released normal phosphoric acid is taken into the activated sludge more than that released in the anaerobic tank in the subsequent aerobic tank. It is possible to remove phosphorus from the soil.

  The seventh characteristic configuration is arranged through an anaerobic tank for denitrifying treated water by anaerobic microorganisms, an anaerobic tank and a partition, and flows from the anoxic tank as described in claim 7 An aerobic tank that nitrifies the ammonia contained in the water to be treated with aerobic microorganisms, and a membrane separation device that is placed through the aerobic tank and the partition wall to separate the treated water that has been nitrified in the aerobic tank. A sewage treatment facility equipped with a membrane separation tank and a pump mechanism for returning a part of the water to be treated in the membrane separation tank to the anoxic tank, to be treated to flow into the membrane separation tank from the aerobic tank In the vicinity of the partition in the second region, a separation wall for separating the membrane separation tank is provided in the first region for receiving water and the second region for guiding the treated water flowing from the first region to the partition in the aerobic tank. The pump mechanism is equipped with a pumping pipe disposed near the partition wall and air bubbles are supplied to the pumping pipe. That the air diffuser, in that it is constituted by an air lift pump having a feed water channel is transferred to the anoxic tank water to be treated is pumped from the top of the riser pipe by the bubble.

  According to the configuration described above, even when part of the treated water is returned from the membrane separation tank to the anoxic tank, it is located on the most downstream side of the second region of the membrane separation tank, that is, in the vicinity of the partition wall with the aerobic tank. Since it is returned to the oxygen-free tank by the installed pump mechanism, the piping that serves as the return path of the water to be treated can be shortened and the structure can be simplified. Can be reduced.

  The characteristic configuration of the method for renovating a sewage treatment facility according to the present invention is that, as described in claim 8, the water to be treated is treated by a treatment tank partitioned by a side wall with an upper portion extending toward the central portion of the upper space. A method for renovating a sewage treatment facility to be treated, which is disposed through an anaerobic tank for denitrifying treated water by at least anaerobic microorganisms, an anaerobic tank and a partition wall, and to the treated water flowing from the anoxic tank A sewage treatment path including an aerobic tank for nitrifying the contained ammonia with an aerobic microorganism is disposed, and a pair of first areas for receiving treated water flowing from the anaerobic tank into the aerobic tank, and a pair of first areas A step of providing a separation wall for separating the aerobic tank so as to form a second region for guiding the treated water flowing from the first region to the partition wall, and aeration of the treated water in the first region The process of installing the diffuser and the second area to be treated The step of installing the filtration membrane of the membrane separator to be separated between the inside of the tank and the outside of the tank, and the pumping pipe disposed in the vicinity of the partition wall on the downstream side of the membrane separator in the second region, It includes a step of installing an air diffuser that supplies air bubbles to the pumping pipe and an air lift pump that includes a water supply path for transferring the water to be treated pumped by the bubbles from the upper part of the water pumping pipe to the oxygen-free tank.

  According to the above-described configuration, the membrane is compared with the existing standard activated sludge method that does not employ the membrane-separated activated sludge method, the nitrification liquid circulation activated sludge method, and the sewage treatment facility that employs the biological circulation type anaerobic aerobic method. When renovating to a sewage treatment facility that employs a membrane separation activated sludge method with a separation device installed, for example, for the installation space such as a worker's passage and an air supply pipe to the diffuser Even in a side wall structure in which the upper part is partitioned by a side wall extending toward the center of the upper space, the second region sandwiched between the pair of first regions, that is, the central region separated from the side wall By installing the filtration membrane, when the filtration membrane is moved up and down between the inside of the tank and the outside of the tank for the maintenance of the filtration membrane, it does not interfere with the extending part at the upper part of the side wall. This eliminates the need for a large-scale construction that scrapes off the existing extended portion of the side wall.

  Also, by installing an air lift pump on the downstream side of the membrane separation device in the second region, the transfer path of the water to be treated can be shortened, so the power of the air lift pump can be reduced and efficient processing can be performed. It can be renovated to a sewage treatment facility.

  The second characteristic configuration of the sewage treatment facility renovation method is that, as described in claim 9, a plurality of sewage treatment paths are arranged in parallel, and the upper part extends toward the central part of the upper space of the treatment tank. Each process is applied to a sewage treatment facility in which a treatment tank adjacent to each sewage treatment path is defined by a side wall having a Y-shaped cross section.

  In an existing sewage treatment facility in which a plurality of sewage treatment paths are arranged in parallel, when the treatment tank adjacent to each sewage treatment path is partitioned by a Y-shaped side wall, the remodeling method according to the present invention is performed. It can be suitably used.

  As described above, according to the present invention, it is possible to provide a sewage treatment facility capable of reducing the power of the pump mechanism necessary for returning from the aerobic tank to the anoxic tank and performing an efficient treatment. It was.

Explanatory drawing by the planar view of the sewage treatment facility by this invention Explanatory drawing by the sectional view by the side of the 1st field of the sewage treatment equipment by the present invention Explanatory drawing by sectional view by the side of the 2nd field of sewage treatment equipment by the present invention Explanatory drawing of the air lift pump used for the sewage treatment facility by this invention Explanatory drawing by plane view which shows another embodiment and the sewage treatment equipment by this invention Cutaway perspective view of a sewage treatment facility according to the present invention showing another embodiment Sectional drawing of the aerobic tank of the wastewater treatment facility by this invention which shows another embodiment (A) shows another embodiment and is explanatory drawing by planar view of the sewage treatment facility by this invention, (b) shows another embodiment and explanatory drawing by planar view of the sewage treatment facility by this invention (A) shows another embodiment and is explanatory drawing by planar view of the sewage treatment facility by this invention, (b) shows another embodiment and explanatory drawing by planar view of the sewage treatment facility by this invention (A) shows another embodiment, explanatory drawing by planar view of the sewage treatment facility by this invention, (b) shows another embodiment, explanatory drawing by sectional view of the sewage treatment facility by this invention, (c) is Explanatory drawing by the side view of the sewage treatment equipment by this invention which shows another embodiment (A) shows another embodiment, explanatory drawing by planar view of the sewage treatment facility by this invention, (b) shows another embodiment, explanatory drawing by sectional view of the sewage treatment facility by this invention, Explanatory drawing of conventional sewage treatment equipment adopting nitrification liquid circulation activated sludge method Explanatory drawing of conventional sewage treatment equipment that uses the biocirculating anaerobic aerobic method

Hereinafter, the sewage treatment facility according to the present invention will be described.
As shown in FIGS. 1, 2, and 3, the sewage treatment facility 1 is connected to an anaerobic tank 10 into which raw water that is untreated water flows, and a downstream side of the anaerobic tank 10 via a partition wall 11. The oxygen-free tank 20 for denitrifying the water to be treated by anaerobic microorganisms, and the ammonia contained in the water to be treated flowing from the oxygen-free tank 20 are arranged on the downstream side of the oxygen-free tank 20 via the partition wall 21. An aerobic tank 30 that nitrifies with aerobic microorganisms and a pump mechanism 40 that returns a portion of the water to be treated nitrified in the aerobic tank 30 to the anoxic tank 20 are provided.

  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 water to be treated flowing from the oxygen-free tank 20 and the second region 32 that guides the water to be treated flowing from the first region 31 to the partition wall 22 A separation wall 34 that separates the aerobic tank 30 along the inflow 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 in the second region 32. A plurality of membrane separation devices 36 for solid-liquid separation are installed, and a pump mechanism 40 is installed downstream of the second region 32. The separation wall 34 is constituted 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 by aeration by the aeration device 35. Furthermore, 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 the water tank (not shown) in the subsequent stage through the water supply pipe 37. The 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 flat membrane, a hollow fiber 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 aeration device 38 for removing and cleaning sludge adhering to the membrane surface of each membrane separation device 36 is disposed below the plurality of membrane separation devices 36. In the second region 32, nitrification is performed by activated sludge under aerobic conditions with air supplied from the aeration device 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 the air diffuser from the air device 35 and the flow of the air diffuser from the aeration device 38 does not occur.

  As shown in FIGS. 3 and 4, the pump mechanism 40 includes a pumping pipe 41 disposed in the vicinity of the partition wall 21, an air diffuser 42 for supplying bubbles to the pumping pipe 41 by a blower, and water to be treated pumped by the bubbles. Is formed of an air lift pump 44 provided with a water supply passage 43 for transferring the water from the upper part of the pumping pipe 41 to the upstream side of the oxygen-free tank 20.

  In the air diffuser 42, a plurality of short pipes having innumerable micro holes are arranged corresponding to the lower opening of the water pumping pipe 41, and are connected to the flower through the air feeding pipe.

  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 44. 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.

  The air lift pump 44 is installed at an appropriate position near the partition wall 21 by the mount 45.

  By disposing the air lift pump 44 in the vicinity of the partition wall 21 and shortening the water supply passage 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 the water to be treated having a high dissolved oxygen concentration can be prevented from flowing into the oxygen-free tank 20 by reducing the amount of air diffused, the possibility of reducing the denitrification efficiency of the oxygen-free tank 20 can be reduced.

  Further, part of the water to be treated returned to the anaerobic tank 20 via the air lift pump 44 is returned to the anaerobic tank 10 via the water supply path 23. Microorganisms in the aerobic tank 30 taking up 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.

  With the above configuration, the power of the pump mechanism 40 for returning from the aerobic tank 30 to the anoxic tank 20 can be reduced, and efficient processing can be performed.

  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.

  Next, another embodiment according to the present invention will be described.

  In the above-described embodiment, the example in which the water to be treated in the upstream treatment tank flows into the downstream treatment tank through the communication port formed in the lower part of the partition wall has been described. You may comprise so that treated water may overflow a partition and may flow in into a downstream processing tank. In this case, the partition between the second region and the upstream oxygen-free tank may be formed so as to protrude above the water surface and not flow into the second region from the oxygen-free tank.

  In the above-described embodiment, the configuration in which the aerobic tank 30 includes the single separation wall 34 has been described. However, as illustrated in FIGS. 5 and 6, the separation walls 34 a and 34 b that separate the aerobic tank 30 are covered. Two sheets may be provided along the inflow direction of the treated water, and the second region 32 may be formed between the pair of first regions 31a and 31b. 5 and 6, the description of the water supply pipe 37 of the water to be treated separated by the membrane separator 36 and the activated sludge extraction pipe 39 of the second region 32 is omitted.

  The filtration membrane of the membrane separator 36 is preferably installed so that it can be pulled out of the tank during maintenance, but as shown in FIG. 7, the existing standard activated sludge method, nitrification liquid circulation activity When the membrane separation device 36 is installed in the aerobic tank 30 of the sewage treatment facility that adopts the sludge method or the biological circulation type anaerobic aerobic method, depending on the shape of each treatment tank, for example, a passage for an operator or an aeration When the top surface 51 extends from the upper part of the side wall of the aerobic tank toward the central part of the upper space of the aerobic tank due to the installation space such as the air supply pipe to the apparatus, and the opening 52 has only the central part There is.

  Even in such a case, if the membrane separation device is installed in the second region formed between the pair of first regions, the membrane of the membrane separation device 36 is lifted from the opening 52 without interfering with the top surface. Maintenance is possible.

  In particular, a membrane separation device was installed for the existing standard activated sludge method that does not use the membrane separation activated sludge method, the nitrification liquid circulation activated sludge method, and the sewage treatment facility that adopted the biological circulation type anaerobic aerobic method. It is suitable when renovating to a sewage treatment facility that employs a membrane separation type activated sludge method.

  In such an existing sewage treatment facility, the top surface extends toward the center of the upper space of the tank for the installation space such as the worker's passage and the air supply pipe to the diffuser. This is because a side wall structure that is partitioned by a Y-shaped side wall is often employed.

  When renovating a sewage treatment facility that treats treated water with a treatment tank that is partitioned by a sidewall that extends upward toward the center of the upper space, the treated water is denitrified at least by anaerobic microorganisms. An anaerobic tank, an anaerobic tank and a partition wall, and a sewage treatment path including an aerobic tank for nitrifying ammonia contained in the water to be treated flowing in from the anaerobic tank with an aerobic microorganism are disposed. A pair of first regions for receiving the water to be treated flowing from the oxygen-free tank and a second region for guiding the water to be treated flowing from the first region to the partition are formed in the air tank. As described above, the step of providing a separation wall for separating the aerobic tank along the inflow direction of the water to be treated, the step of installing a diffuser for aeration of the water to be treated in the first region, and the second region The membrane of the membrane separator that separates the water to be treated from the inside of the tank to the outside of the tank A step of installing freely, a pumping pipe disposed in the vicinity of the partition wall in the second region downstream of the membrane separation device, an air diffuser for supplying bubbles to the pumping pipe, and a target pumped by the bubbles. It can be suitably remodeled by a process of installing an air lift pump provided with a water supply path for transferring treated water from the upper part of the pumping pipe to the oxygen-free tank.

  By installing the filtration membrane in the second region sandwiched between the pair of first regions, that is, the central region separated from the side wall, the filtration membrane is moved up and down between the inside and outside of the tank for the maintenance of the filtration membrane. In such a case, since there is no interference with the extension part at the upper part of the side wall, a large-scale construction for scraping off the extension part at the upper part of the side wall becomes unnecessary.

  A sewage treatment system in which a plurality of sewage treatment paths are arranged in parallel, and a treatment tank adjacent to each sewage treatment path is defined by a Y-shaped side wall having an upper portion extending toward the center of the upper space of the treatment tank. It is particularly preferable that each process is applied to the equipment.

  In embodiment mentioned above, the pump mechanism 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 were provided. Although the configuration has been described, the water to be treated in the second region 32 fed by the pump mechanism is not provided with the return path 23 and is configured to return a predetermined amount to each of the anaerobic tank 20 and the anaerobic tank 10. Also good.

  Although the above-described air lift pump 44 has been described with respect to the configuration in which the air diffuser 42 is installed below the pumping pipe 41, the air diffuser 42 does not necessarily need to be below the water pumping pipe 41, and the side wall surface of the water pumping pipe 41. You may comprise so that a bubble may be supplied in a pipe | tube from the opening formed in this.

  In addition, the air lift pump as the pump mechanism is preferable in that there is no possibility of damaging the carrier with the impeller unlike the mechanical pump when the carrier carrying the microorganism is circulated and supplied, but the carrier carrying the microorganism is used. In the case where the activated sludge is circulated and supplied, a mechanical submersible pump may be installed in the second region to return a part of the treated water.

  In the above-described embodiment, the configuration in which the present invention is applied to a membrane separation activated sludge method provided with a membrane separation apparatus has been described. However, the circulation digestion denitrification method shown in FIG. 8A or FIG. As shown in Fig. 4, it can be applied to a biocirculation anaerobic aerobic method without a membrane separation device.

  In the embodiment described above, as shown in FIGS. 9A and 9B, the partition wall 50 that further partitions the first region 31 in the first region 31 is provided, and each of the regions partitioned by the partition wall 50 is provided. Alternatively, the diffuser 35 may be installed so that the water to be treated meanders in the partitioned area. By comprising in this way, to-be-processed water passes through the 1st area | region 31, the aeration apparatus reliably diffuses, and the efficiency of an aerobic process increases.

  The partition wall 50 is not limited to the case in which the partition wall 50 is provided along the inflow direction of the water to be treated flowing into the first region 31 from the anoxic tank 20, and is provided in a direction perpendicular to the inflow direction of the water to be treated. May be.

  Similarly, the second region 32 is provided with a partition wall so as to meander the water to be treated, a membrane separation device is provided in each of the regions partitioned by the partition wall, and the most downstream side of the partitioned second region. You may comprise so that an air lift pump may be installed.

  In the embodiment described above, the separation wall 34 includes the first region 31 that receives the water to be treated flowing from the anoxic tank 20 and the second region 32 that guides the water to be treated flowing from the first region 31 to the partition wall 22. The aerobic tank 30 is separated along the inflow direction of the water to be treated, and its upper edge is composed of one or two substantially vertical walls projecting upward from the water surface, and the base end side is joined to the partition wall 21; Although the configuration in which the other end side is opened in the aerobic tank 30 has been described, as shown in FIGS. 10A, 10 </ b> B, and 10 </ b> C, the separation wall 34 is connected to the anaerobic tank 20 and the aerobic tank. 30 is formed to extend into the aerobic tank 30 from the opening 22 formed in the center lower part of the partition wall 21 and to form a water passage for the water to be treated, that is, a separation wall that divides the tank vertically. May be. In this case, the inside of the water passage of the water to be treated surrounded by the separation wall 34 of the aerobic tank 30 becomes the first region 31, the periphery thereof becomes the second region 32, and the pump mechanism 40 is installed in the vicinity of the partition wall 21. .

  And it is the 2nd area | region 32, it is the circumference | surroundings of the water flow path enclosed by the separation wall 34, Comprising: While installing the diffuser 35 which diffuses to-be-processed water in parallel with a water flow path, it surrounds with the separation wall 34 The membrane separation device 36 for solid-liquid separation of the water to be treated may be installed at the upper part of the water passage. The air diffuser 35 is not necessarily installed in the second region 32, and may be installed in the first region 31 inside the water passage surrounded by the separation wall 34.

  Further, as shown in FIGS. 11A and 11B, the anoxic tank 20 for denitrifying the water to be treated by anaerobic microorganisms, an anoxic tank 20 and a partition wall 21 are disposed. The aerobic tank 30 nitrifies ammonia contained in the water to be treated flowing in from the aerobic microorganisms, and the aerobic tank 30 and the partition wall 34, and the treated water nitrified in the aerobic tank 30 is solid-liquid. In a sewage treatment facility having a membrane separation tank 55 in which a membrane separation device 36 for separation and a pump mechanism for returning a part of water to be treated in the membrane separation tank 55 to the anoxic tank 20 are provided, the membrane separation tank 55 In addition, the first region that receives the treated water flowing from the aerobic tank 30 and the second region 32 that guides the treated water flowing from the first region 31 to the partition wall 56 between the aerobic tank 30 and the treated water. A separation wall 34 for separating the membrane separation tank 55 along the inflow direction of Near the second partition 56 comprises an air lift pump 44 described above, it can also be configured to return a portion of the water to be treated anoxic tank 20 by the air lift pump 44.

  In this case, a membrane separation device 36 is installed in the second region 32. The first region 31 may simply be configured to function as a flow path, or an air diffuser 35 may be installed.

  Even when such a configuration is adopted, the piping serving as the return path of the water to be treated can be shortened and the structure can be simplified, so that the power of the pump mechanism necessary for returning the water to be treated is reduced. be able to.

  The separation wall 34 may be either a vertical wall as described with reference to FIG. 1 or a separation wall 34 that partitions the inside of the tank up and down as described with reference to FIG.

  That is, in the sewage treatment facility according to the present invention, a plurality of treatment tanks that purify the treated water by microorganisms are connected via the partition walls, and a part of the treated water is transferred to the downstream treatment tank. Applicable to sewage treatment facilities equipped with a pump mechanism for returning, a first region for receiving the treated water flowing from the upstream treatment tank into the downstream treatment tank, and the treated water flowing from the first region A separation wall that separates the downstream treatment tank along the inflow direction of the water to be treated is provided in the second region leading to the partition wall with the upstream treatment tank, and a pump mechanism is provided at least near the partition wall in the second region. The pump mechanism is disposed upstream of the pumping pipe from the upper part of the pumping pipe, the pumping pipe disposed in the vicinity of the partition wall, the air diffuser for supplying bubbles to the pumping pipe, and the treated water pumped by the bubbles Air lift with a water supply channel to transfer to any processing tank It may be composed in amplifier.

  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.

10: Anaerobic tank 20: Anoxic tank 30: Aerobic tank 31: First region 32: Second region 36: Membrane separation device 40: Pump mechanism 44: Air lift pump

Claims (9)

A plurality of treatment tanks that purify treated water by microorganisms are connected via a partition wall, and are equipped with a pump mechanism that returns a part of the treated water to the upstream treatment tank to the downstream treatment tank. Equipment,
A first area that receives the water to be treated flowing from the upstream treatment tank into the downstream treatment tank, and a second area that guides the water to be treated flowing from the first area to the partition wall with the upstream treatment tank. A separation wall for separating the downstream processing tank is provided, and a pump mechanism is provided at least in the vicinity of the partition wall in the second region, and the pump mechanism supplies a bubble to the pumping pipe disposed in the vicinity of the partition wall. A sewage treatment facility comprising an air diffusing device and an air lift pump provided with a water supply path for transferring the water to be treated pumped up by air bubbles from the upper part of the pumping pipe to a treatment tank disposed upstream. An anaerobic tank that denitrifies the water to be treated by anaerobic microorganisms, and an aerobic tank that is disposed through the anoxic tank and the partition wall and nitrifies ammonia contained in the water to be treated flowing from the anaerobic tank with the aerobic microorganisms. And a sewage treatment facility equipped with a pump mechanism for returning part of the treated water nitrified in the aerobic tank to the anoxic tank,
In the aerobic tank, a separation wall for separating the aerobic tank is provided in the first area for receiving the water to be treated flowing from the anoxic tank and the second area for guiding the water to be treated flowing from the first area to the partition wall. In addition, an air diffuser that diffuses the water to be treated is installed at least in either the first region or the second region, and a pump mechanism is provided on the downstream side of the second region, and the pump mechanism is located near the partition wall. It is composed of an arranged pumping pipe, an air diffuser for supplying bubbles to the pumping pipe, and an air lift pump having a water supply path for transferring the water to be treated pumped by the bubbles from the upper part of the pumping pipe to the oxygen-free tank Sewage treatment equipment.   The sewage treatment facility according to claim 2, wherein an air diffuser that diffuses the water to be treated is installed in the first area, and a membrane separation device that separates the water to be treated is solid-liquid separated in the second area.   The sewage treatment facility according to claim 3, wherein the volume of the first region separated by the separation wall is set to be larger than the volume of the second region.   The sewage treatment facility according to claim 3 or 4, wherein two separation walls for separating the aerobic tank are provided along the inflow direction of the water to be treated, and the second region is formed between the pair of first regions.   An anaerobic tank for removing the BOD component contained in the treated water is connected to the upstream side of the anaerobic tank via a partition wall, and the treated water in the aerobic tank is returned to the anoxic tank via an air lift pump. The sewage treatment facility according to claim 2, wherein a part of the sewage treatment facility is returned to the anaerobic tank. An anaerobic tank that denitrifies the water to be treated by anaerobic microorganisms, and an aerobic tank that is disposed through the anoxic tank and the partition wall and nitrifies ammonia contained in the water to be treated flowing from the anaerobic tank with the aerobic microorganisms. And a membrane separation tank in which a membrane separation device for solid-liquid separation of the treated water nitrified in the aerobic tank is installed, and a part of the treated water in the membrane separation tank A sewage treatment facility equipped with a pump mechanism for returning the water to the anoxic tank,
The membrane separation tank is separated into a membrane separation tank into a first area for receiving the treated water flowing from the aerobic tank and a second area for guiding the treated water flowing from the first area to the partition wall with the aerobic tank. A separation mechanism is provided, and a pump mechanism is provided in the vicinity of the partition wall in the second region. The pump mechanism includes a pumping pipe disposed in the vicinity of the partition wall, an air diffuser for supplying bubbles to the pumping pipe, and pumping by the bubbles. A sewage treatment facility comprising an air lift pump provided with a water supply path for transferring the treated water to be treated from the upper part of the pumping pipe to the oxygen-free tank. A method for renovating a sewage treatment facility that treats water to be treated by a treatment tank partitioned by a side wall with an upper portion extending toward a central portion of an upper space,
An anaerobic tank that denitrifies the water to be treated by at least anaerobic microorganisms, and an aerobic microorganism that nitrifies ammonia contained in the water to be treated flowing from the anoxic tank through the anoxic tank and the partition wall. A sewage treatment path including the tank is arranged,
In the aerobic tank, a pair of first areas for receiving the water to be treated flowing from the oxygen-free tank and a second area for guiding the water to be treated flowing from the first area to the partition are formed between the pair of first areas. Providing a separation wall for separating the aerobic tank,
A step of installing an air diffuser that diffuses the treated water in the first area;
A step of installing a filtration membrane of a membrane separation device for solid-liquid separation of water to be treated in the second region so as to be movable up and down between the inside of the tank and the outside of the tank;
In the second region, on the downstream side of the membrane separation device, a pumping pipe arranged in the vicinity of the partition wall, an air diffuser for supplying bubbles to the pumping tube, and treated water pumped up by the bubbles from above the pumping pipe A method for renovating a sewage treatment facility including a step of installing an air lift pump provided with a water supply channel for transfer to an anoxic tank.   A sewage treatment system in which a plurality of sewage treatment paths are arranged in parallel, and a treatment tank adjacent to each sewage treatment path is defined by a Y-shaped side wall having an upper portion extending toward the center of the upper space of the treatment tank. The method for renovating a sewage treatment facility according to claim 8, wherein each step is applied to the facility.

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