JP2013000670A - Sewage treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewage treatment apparatus which efficiently eliminates organic pollution material, a nitrogen compound, and a phosphorus compound by combining a biotreatment device and a membrane separation device, and which reduces a load on the membrane separation device and stably obtains high-quality reclaimed water.SOLUTION: The sewage treatment apparatus includes a purification device 3A which receives and purifies a part of sewage flowing to a trunk sewer; the biotreatment device 7 which biologically eliminates the organic pollution material, nitrogen compound, and phosphorus compound from treated water obtained by the purification device 3A; the membrane separation device 9 which separates and eliminates sludge from the biologically-treated water obtained by the biotreatment device 7 and obtains the reclaimed water. The purification device 3A includes a storage tank 11 combining an oil floating and separating unit which floats and separates oil from the sewage, a solid settling and separating unit which settles and separates solids in the sewage, and a solubilizing device which retains and solubilizes the solids settled and separated by the solid settling and separating unit.

Description

  The present invention relates to a sewage treatment apparatus that receives sewage discharged from an apartment house or the like toward a sewer main line and biologically removes organic pollutants, nitrogen compounds, and phosphorus compounds in the sewage to obtain reclaimed water.

  There is known a satellite treatment plant that draws sewage from an upstream branch pipe connected to a sewer main line, processes the sewage, and supplies it as reclaimed water to an urban area or the like. For example, Patent Document 1 discloses an example of a sewage treatment apparatus installed in a satellite treatment plant. This sewage treatment apparatus obtains reclaimed water by performing pretreatment of sewage by high-speed filtration using a floating filter medium, and then removing organic substances and the like by a biological treatment apparatus including an anaerobic tank and an aerobic tank. In particular, in this apparatus, a membrane separation apparatus is provided in the aerobic tank in order to save space.

JP 2008-705 A

  In recent years, with the widespread use of reclaimed water, it has been desired to improve the quality of reclaimed water, and nitrogen and phosphorus compounds contained in reclaimed water have also been regarded as problems. However, although the conventional sewage treatment apparatus includes a biological treatment apparatus including an anaerobic tank and an aerobic tank, since this apparatus performs high-speed filtration as a pretreatment, organic substances necessary for removing nitrogen and phosphorus compounds are used. Ingredients may be removed excessively. In addition, the amount of the organic component dissolved in the sewage varies depending on the nature of the sewage. If the amount of the organic component is small, the action of microorganisms is suppressed and the denitrification reaction is insufficient. Further, when the amount of the organic component is small, the phosphorus compound is not sufficiently captured by the microorganisms, and it becomes difficult to substantially separate the phosphorus compound by the membrane separation device, and it becomes difficult to obtain high-quality recycled water. On the other hand, if it is set as the apparatus structure which abbreviate | omitted the pretreatment, the load to a membrane separator will become excessive and it will become difficult to obtain reclaimed water stably.

  The present invention aims to solve the above-mentioned problems, and effectively removes organic pollutants, nitrogen compounds, and phosphorus compounds by using a biological treatment apparatus and a membrane separation apparatus together with a membrane separation apparatus. It is an object of the present invention to provide a sewage treatment apparatus that can stably obtain high-quality reclaimed water by reducing the load of water.

  The present invention biologically removes organic pollutants, nitrogen compounds, and phosphorus compounds from a purification device that receives and purifies part of the sewage flowing toward the sewer main line, and the treated water obtained by the purification device. And a membrane separation device that separates and removes turbidity from the biologically treated water obtained by the biological treatment device to obtain reclaimed water, and the purification device floats and separates the oil component that floats and separates the oil component in the sewage And a solid content sedimentation and separation means for sedimenting and separating solids in sewage, and a solubilization means for retaining and solubilizing the solids sedimented and separated by the solid content sedimentation and separation means. Sewage treatment equipment.

  According to the present invention, the oil component and the solid component that give an overload to the membrane separation device are removed by the purification device in the previous stage. Furthermore, the purification device is equipped with a solubilizing means for solubilizing the solid content settled and separated by the solid content sedimentation separating means, and is necessary for biologically removing nitrogen compounds and phosphorus compounds in the biological treatment equipment. The organic component that becomes can be supplemented by solubilization of the solid content. As a result, the combined use of biological treatment equipment and membrane separation equipment effectively removes organic pollutants, nitrogen compounds, and phosphorus compounds, while reducing the load on the membrane separation equipment and stabilizing high-quality reclaimed water. Can be obtained.

  Moreover, the residence time of the sewage in the solubilization means is preferably 1 hour or more and 24 hours or less, and the residence time of the sewage in the solubilization means is 2 hours or more and 8 hours or less. Further preferred.

  Furthermore, it is preferable to provide a solid-liquid separation device that physically separates and removes the remaining impurities in the treated water obtained by the purification device and supplies the treated water from which the remaining impurities have been removed to the biological treatment device. By removing the remaining contaminants, the load applied to the membrane separation device is further reduced.

  Further, the purification device has a sewage storage tank functioning as an oil flotation separating means and a solid sedimentation separating means, and the storage tank holds the sewage from the sewage by holding the sewage in a stationary state. It is preferable to have a tank main body that floats and separates the oil content and settles and separates the solid content from the sewage, and a discharge unit that discharges the oil and the treated water from which the solid content has been separated from the tank main body. According to this configuration, the sewage storage tank can be used for both the oil flotation separation means and the solid sedimentation separation means, which is advantageous for space saving. Further, the oil content, solid content, and treated water can be simplified by the difference in specific gravity. It is advantageous to simplify the device configuration.

  Further, the tank main body has a bottom portion on which the sedimented solid content is deposited, and a side wall that holds the solid content while being erected along the periphery of the bottom portion, and the solubilizing means is a bottom portion that retains the solid content. , And the side wall. According to the said structure, the structure which makes solid content settled and separated from sewage retain for solubilization is easily realizable.

  Furthermore, the storage tank preferably includes a partition wall that partitions the tank body and a communication hole that connects adjacent storage chambers with the partition wall interposed therebetween. By separating the tank main body of the storage tank with a partition wall, it is possible to expect removal of residual contaminants in the sewage, and particularly when a solid-liquid separator is arranged in the subsequent stage, the load on the solid-liquid separator can be reduced.

  Furthermore, the introduction unit is provided in any one of the plurality of storage chambers partitioned by the partition wall, and the discharge unit is a storage chamber in which the introduction unit is provided among the plurality of storage chambers. It is suitable if it is provided in another storage chamber. According to this configuration, since the discharge unit is provided in a storage chamber different from the storage chamber in which the introduction unit is provided, in the downstream storage chamber in which the discharge unit is provided, the sewage introduced in the introduction unit It becomes difficult to be influenced by the flow, and therefore, it becomes easy to keep the sewage in a stationary state in the downstream storage chamber.

  According to the present invention, organic contaminants, nitrogen compounds, and phosphorus compounds are effectively removed by using a biological treatment device and a membrane separation device in combination, and the load on the membrane separation device is reduced to produce high-quality recycled water. Can be obtained stably.

It is a figure which shows roughly the relationship between the sewage treatment apparatus which concerns on embodiment of this invention, and a sewer main line. It is a figure which shows typically the sewage treatment apparatus which concerns on embodiment of this invention. It is sectional drawing which shows typically the purification apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing which shows typically the solid-liquid separation apparatus which concerns on this embodiment. It is a figure which shows typically the biological treatment apparatus which concerns on this embodiment. It is sectional drawing which shows typically the purification apparatus which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows typically the purification apparatus which concerns on 3rd Embodiment of this invention.

  Hereinafter, a sewage treatment apparatus according to a preferred embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment, The aspect which embodies this invention is included widely.

  As shown in FIG. 1, the sewage treatment apparatus 1A accepts sewage discharged from an apartment house or factory toward a sewer main line, and biologically removes organic pollutants, nitrogen compounds, and phosphorus compounds in the sewage. It is a device that removes to obtain reclaimed water. In addition, acceptance of sewage may be part of sewage discharged in units of facilities such as apartment houses or factories, or part of combined sewage discharged from multiple facilities in a specific area. Also good. In addition, by making the sewage received by the sewage treatment apparatus 1A a part of the drainage amount (total amount), the size can be adjusted according to the required facilities without being affected by the fluctuation of the drainage amount, and the economy is improved.

As shown in FIG. 2, a sewage treatment apparatus 1A according to the first embodiment includes a purification apparatus 3A that receives and purifies sewage, and residual impurities (for example, hair) in treated water obtained by the purification apparatus 3A. And the like, and organic contaminants, nitrogen compounds, and phosphorus compounds are biologically removed from the solid-liquid separation device 5 that physically separates and removes, and the secondary treated water obtained by the solid-liquid separation device 5. A biological treatment device 7 and a membrane separation device 9 that separates and removes turbidity from the biological treatment water obtained by the biological treatment device 7 to obtain reclaimed water are provided.
[Purification device]

  First, the purification device 3A will be described with reference to FIG. The purification apparatus 3A includes an oil content floating separation means, a solid content sedimentation separation means, and a solubilization means. The oil flotation separation means is means for separating the water W and the fats and oils F in the sewage using the difference in specific gravity, and the solid sedimentation separation means is a coarse solid content (solid content) S such as feces. Is a means for settling and separating coarse solids S from sewage using the specific gravity difference between water and water W. The solubilizing means is a means for solubilizing the sedimented and deposited coarse solids S for a long time.

  The purification apparatus 3A according to the present embodiment includes a sewage storage tank 11A that functions as an oil content floating separation unit, a solid content settling separation unit, and a solubilization unit. The storage tank 11A includes an introduction pipe (introduction section) 13 that receives sewage, a tank body 15A that stores sewage, and a discharge pipe (discharge section) that discharges treated water (hereinafter referred to as “primary treated water”) from the tank body 15A. 17.

  The introduction pipe (introduction section) 13 that receives sewage passes through the side wall 25 of the tank body 15A, is bent in the storage tank 11A, and is arranged so that the pipe outlet 13c faces downward in the storage tank 11A. . The pipe outlet 13c is preferably disposed below the oil layer when it is assumed that an oil layer generated at a predetermined water level is assumed because it is preferable to prevent the oil and fat layer (hereinafter referred to as "oil layer") from being mixed with the inflowing sewage. Is preferred.

  A discharge pipe (discharge section) 17 that discharges the treated water is disposed to face the introduction pipe 13 and penetrates the side wall 25 of the tank body 15A and bends in the tank body 15A. It arrange | positions so that it may face the downward direction of 15 A of tank main bodies. Since it is preferable that the pipe outlet 17c can prevent the oil layer from being stirred, it is preferable to dispose the pipe outlet 17c below the oil layer when an oil layer generated at a predetermined water level is assumed.

  Further, since the pipe outlet 17c of the discharge pipe 17 needs to prevent the suction of the coarse solid content S that settles and deposits in the tank body 15A, the bulk of the coarse solid content S that accumulates in the tank body 15A is assumed. It is arranged to be at a position higher than its bulk.

  The sewage is introduced into the tank body 15A through the introduction pipe 13, and is kept stationary by the tank body 15A. At that time, the oil and fat F in the sewage is floated and separated, and the coarse solid S is settled and separated.

  15 A of tank main bodies have the bottom part 21 in which the coarse solid content S settled and separated from the sewage deposits, and the side wall 25 which hold | maintains the coarse solid content S while standing along the periphery of the bottom part 21. As shown in FIG. Accordingly, the coarse solid content S settled and separated from the sewage is held at a fixed position by the bottom 21 and the side wall 25 and stays in the tank body 15A for a predetermined time. As a result, elution of the organic component in the coarse solid content S into the primary treated water is achieved.

  The solubilization of the organic component in the coarse solid S requires 1 to 24 hours, preferably 2 to 8 hours. Therefore, in order to realize the storage tank 11A as a solubilizing means, the residence time of the coarse solid content S is designed to be 1 hour or more and 24 hours or less, and more preferably, the residence time is It is necessary to design for 2 hours or more and 8 hours or less.

In addition, the residence time of sewage can be determined by design by the inflow flow rate of sewage, the discharge flow rate of sewage, and the volume of the tank body 15A of the storage tank 11A. For example, if the time inflow amount is 15 m ³ , it is 15 m ^{3 to} 360 m ³ (1 to 24 hr retention), and preferably 30 m ^{3 to} 120 m ³ (2 to 8 hr residence).

  A long residence time is advantageous for solubilizing organic components, but on the other hand, the capacity of the tank main body 15A is increased and the equipment becomes excessive, which is disadvantageous in terms of processing efficiency and cost. . In addition, when the residence time is increased, the organic component solubilized at the bottom is anaerobic, decomposition of the organic matter proceeds, and the solubilizing effect is impaired. Accordingly, the storage tank 11A needs to be designed so that the residence time of the coarse solid content S is 24 hours or less, preferably 8 hours or less, as an upper limit.

Due to the function of the tank body 15A as the solubilizing means, the primary treated water from which the organic component in the coarse solid S is eluted is discharged from the discharge pipe 17 and passes through the primary treated water discharge line 27 provided with a transfer pipe. It is supplied to the solid-liquid separator 5.
[Solid-liquid separator]

  As shown in FIG. 2 and FIG. 4, the solid-liquid separation device 5 includes a water storage unit 29 that receives primary treated water, an upstream region (primary region) 29 a and a downstream region (secondary region) in the water storage unit 29. And a fine contaminant separating unit 31 arranged so as to be divided into a side region 29b. As the fine contaminant separation unit 31, a drum-type screen or a bar screen can be appropriately applied. However, in order to effectively remove fibrous contaminants such as hair, solid-liquid separation is performed by a mesh-shaped drum. A drum-type screen is more advantageous.

The primary treated water introduction part 32 is provided in the primary side area 29a of the water storage part 29, and the secondary treated water after the fine contaminants are removed by the fine contaminant separating part 31 in the secondary side area 29b. A discharge part 33 for discharging (hereinafter referred to as “secondary treated water”) is provided. The discharge unit 33 is connected to a secondary treated water transfer line 30 having a transfer pipe that communicates with the biological treatment apparatus 7 at the subsequent stage. A valve 30a that opens and closes is provided. Further, the fine contaminants removed by the fine contaminant separation unit 31 are received by the bucket 34 and discharged.
[Biological treatment apparatus and membrane separation apparatus]

  As shown in FIGS. 2 and 5, the biological treatment device 7 and the membrane separation device 9 remove organic substances contained in the secondary treated water with activated sludge and remove nitrogen and phosphorus from the secondary treated water. It is a highly processing device. The biological treatment apparatus 7 according to this embodiment includes an anaerobic tank 37, an anaerobic tank 38, and an aerobic tank 39 arranged in order from the upstream side. Specifically, the anaerobic-anoxic-aerobic method. It is an apparatus that embodies a processing method called (A2O method). The membrane separation device 9 according to the present embodiment is a device that separates and removes turbidity such as sludge from biologically treated water containing activated sludge obtained by the biological treatment device 7 to obtain reclaimed water. Specifically, It is an apparatus that embodies a treatment system called a membrane separation activated sludge process (MBR).

  The biological treatment apparatus 7 includes an adjustment tank 40 that receives the secondary treatment water upstream of the anaerobic tank 37, and the secondary treatment water supplied into the adjustment tank 40 is supplied to the anaerobic tank 37 by the pump 41. Is done. In addition, the biological treatment apparatus 7 is provided with a circulation pipe 42 for sending the nitrification liquid from the aerobic tank 39 to the preceding anaerobic tank 38 and a return pipe 43 for sending the returned sludge from the aerobic tank 39 to the anaerobic tank 37. ing. Further, a stirring blade 44 is installed in the anaerobic tank 37 and the anaerobic tank 38, and an aeration tube 46 for diffusing the air supplied from the blower 45 is provided in the aerobic tank 39.

  The secondary treated water supplied from the adjustment tank 40 into the anaerobic tank 37 is mixed with the return sludge sent by the return pipe 43. The phosphorus accumulating bacteria contained in the returned sludge are taken up in the microbial cells at the same time as taking in the soluble organic matter in the treated water in the anaerobic tank 37 (hereinafter referred to as “biologically treated water”) and the nitrifying liquid from the aerobic tank 39. Release phosphorus.

  Next, the biologically treated water in the anaerobic tank 37 is introduced into the anoxic tank 38. The anaerobic tank 38 is also introduced with a nitrifying liquid from a subsequent aerobic tank 39, and the biologically treated water flowing out of the anaerobic tank 37 and the nitrifying liquid come into contact with each other in an oxygen-free state. The denitrifying bacteria contained in the sludge in the biologically treated water from the anaerobic tank 37 denitrify the organic component in the biologically treated water as a hydrogen donor, so that the nitrate nitrogen in the nitrification solution is changed to nitrogen gas and removed. The

  Next, the biologically treated water in the anoxic tank 38 is introduced into the aerobic tank 39 and subjected to aeration treatment, and the organic matter in the sewage is oxidatively decomposed in the aerobic state, and the organic nitrogen by the nitrifying bacteria in the sludge. And ammonia nitrogen is nitrified. Furthermore, under an aerobic condition, the phosphorus compound in the biologically treated water is excessively ingested by the phosphorus accumulating bacteria, and phosphorus is removed from the liquid by extracting the sludge containing the phosphorus accumulating bacteria out of the system.

  The biologically treated water in the aerobic tank 39, that is, the biologically treated water obtained by the biological treatment device 7 is separated and removed by the membrane separation device 9 into sludge and the like to become reclaimed water. The membrane separation device 9 includes a membrane module 9a having a membrane element such as a hollow fiber membrane, a header pipe 9b connected to the membrane module 9a, and a pump (not shown) that performs suction filtration on the membrane module 9a via the header pipe 9b. ) Etc. The header pipe 9b is connected to a reclaimed water line 51 having a transfer pipe for transferring reclaimed water. The reclaimed water line 51 communicates with apartment buildings, factories, watering facilities, or artificial facilities such as fountains and park ponds, and the reclaimed water transferred by the reclaimed water line 51 is appropriately used in each facility.

  According to the sewage treatment apparatus 1A according to the present embodiment, the oil / fat F and the solid S that give an overload to the membrane separation apparatus 9 are removed by the purification apparatus 3A in the previous stage. Furthermore, the purification device 3A includes a storage tank 11A that functions as a solids sedimentation separation unit and a solubilization unit, and is necessary for biologically removing nitrogen compounds and phosphorus compounds in the biological treatment device 7. The organic component can be supplemented by solubilization of the coarse solid S. As a result, by using the biological treatment device 7 and the membrane separation device 9 together, organic pollutants, nitrogen compounds, and phosphorus compounds are effectively removed, and the load on the membrane separation device 9 is reduced, resulting in high quality. Reclaimed water can be obtained stably.

  As a reference example, for example, a mode in which a screen or the like is provided as a pretreatment process of a biological treatment device without providing a purification device 3A corresponding to the storage tank 11A (referred to as a “normal mode”) is also assumed. In this normal mode, since organic matter such as feces is captured by the screen, the organic matter component cannot be effectively used as in the case of the sewage treatment apparatus 1A.

  Furthermore, in this embodiment, since the oil content floating separation means and the solid content settling separation means can be used in combination by the storage tank 11A of the purification device 3A, it is advantageous for space saving. Since the fraction S and the primary treated water can be easily separated, it is advantageous for simplifying the apparatus configuration.

  Furthermore, in the sewage treatment apparatus 1A, the residual contaminants in the primary treated water obtained by the purification apparatus 3A are physically separated and removed by the solid-liquid separation apparatus 5, thereby reducing the load applied to the membrane separation apparatus 9 at the subsequent stage. it can.

Furthermore, since the solubilization means according to the present embodiment is formed by the bottom portion 21 of the tank body 15A of the storage tank 11A and the side wall 25, a configuration in which the coarse solid content S that has been deposited is retained for solubilization. Easy to implement.
(Sewage treatment apparatus according to the second embodiment)

  Next, the sewage treatment apparatus 1B according to the second embodiment will be described with reference to FIG. In addition, since the substantial difference between the sewage treatment apparatus 1B according to the second embodiment and the sewage treatment apparatus 1A according to the first embodiment is only the purification apparatus 3B, the following description relates to the second embodiment. The purification device 3B will be mainly described. Moreover, since the purification apparatus 3B includes the same elements or structures as the purification apparatus 3A according to the first embodiment, the same elements and structures are denoted by the same reference numerals and detailed description thereof is omitted.

  The purification device 3B is provided with a sewage storage tank 11B that functions as an oil content floating separation means, a solid content sedimentation separation means, and a solubilization means. The storage tank 11B includes an introduction pipe (introduction section) 13 that receives sewage, a tank body 15B that stores sewage, and a discharge pipe (discharge section) that discharges treated water (hereinafter referred to as “primary treated water”) from the tank body 15B. 17.

  The tank main body 15B is divided into three (plural) storage chambers of the upstream chamber 15a, the intermediate chamber 15b, and the downstream chamber 15c by the partition walls 19 and 20, and the bottom 24 of the tank main body 15 includes the partition wall 19, 20 is divided into bottom portions 24a, 24b, and 24c of the upstream chamber 15a, the intermediate chamber 15b, and the downstream chamber 15c, respectively. The first partition wall 19 that divides the upstream chamber 15a and the intermediate chamber 15b is formed with a communication hole 22 that communicates the upstream chamber 15a and the intermediate chamber 15b. The second partition wall 20 that divides the intermediate chamber 15b and the downstream chamber 15c is formed with a communication hole 23 that communicates the intermediate chamber 15b and the downstream chamber 15c. The communication holes 22 and 23 are formed at positions above the bottom 24.

  An introduction pipe (introduction section) 13 for receiving sewage is provided in the upstream chamber 15a. In addition, a discharge pipe (discharge unit) 17 that discharges the treated water is provided in a downstream chamber 15c that is different from the upstream chamber 15a.

  The sewage is introduced into the upstream chamber 15a of the tank body 15 through the introduction pipe 13, and gently flows in the order of the intermediate chamber 15b and the downstream chamber 15c while passing through the communication holes 22 and 23, and is left stationary in the process. Retained. At that time, the oil and fat F in the sewage is levitated and separated in each of the upstream chamber 15a, the intermediate chamber 15b, and the downstream chamber 15c, and the coarse solid component S is also separated by sedimentation. Note that the oil layer and the sedimentation separation layer generated in each of the upstream chamber 15a, the intermediate chamber 15b, and the downstream chamber 15c are thickest in the upstream chamber 15a and thinnest in the downstream chamber 15c.

  The tank body 15 </ b> B includes a bottom 24 on which the coarse solid S precipitated and separated from the sewage is deposited, and a side wall 25 that stands along the periphery of the bottom 24 and holds the coarse solid S. The bottom 24 and the side wall 25 function as a solubilizing means, and the coarse solid content S settled and separated from the sewage is held by the bottom 24 and the side wall 25 and held for a predetermined time.

  In order to realize the storage tank 11B as a solubilizing means, the residence time of the coarse solid content S is designed to be 1 hour or more and 24 hours or less. It is necessary to design for 2 hours or more and 8 hours or less.

  Due to the function of the storage tank 11B as a solubilizing means, in particular, the tank body 15B, the primary treated water from which the organic components in the coarse solids S are eluted is discharged from the discharge pipe 17, and the primary treated water discharged with the transfer pipe is discharged. It is supplied to the solid-liquid separator 5 through the line 27.

  According to the sewage treatment apparatus 1B according to the second embodiment, the same effect as that of the sewage treatment apparatus 1A according to the first embodiment, that is, the oil and fat F and the solid content S that give an overload to the membrane separation device 9 are It is removed in the purification device 3B in the previous stage. Furthermore, the purification device 3B includes a storage tank 11C that functions as a solid sedimentation separation unit and a solubilization unit, and is necessary for biologically removing nitrogen compounds and phosphorus compounds in the biological treatment device 7. The organic component can be supplemented by solubilization of the coarse solid S. As a result, by using the biological treatment device 7 and the membrane separation device 9 together, organic pollutants, nitrogen compounds, and phosphorus compounds are effectively removed, and the load on the membrane separation device 9 is reduced, resulting in high quality. Reclaimed water can be obtained stably.

  Furthermore, according to the sewage treatment apparatus 1B according to the second embodiment, since the tank main body 15B of the storage tank 11B is partitioned by the partition walls 19 and 20, it is possible to expect the removal of residual impurities in the sewage W, and the subsequent stage It is possible to reduce the load on the solid-liquid separation device 5 arranged in the above.

Further, since the introduction pipe 13 of the purification device 3B is provided in the upstream chamber 15a which is a storage chamber different from the downstream chamber 15c in which the discharge pipe 17 is provided, the introduction pipe 13 is introduced from the introduction pipe 13 in the downstream chamber 15c. Therefore, it becomes difficult to be influenced by the flow of sewage, and thus it is easy to keep the sewage in a stationary state in the downstream chamber 15c.
(Sewage treatment apparatus according to the third embodiment)

  Next, a wastewater treatment apparatus 1C according to the third embodiment will be described with reference to FIG. The substantial difference between the sewage treatment apparatus 1C according to the third embodiment and the sewage treatment apparatuses 1A and 1B according to the first and second embodiments is only the purification apparatus 3C. The purification device 3C according to the third embodiment will be mainly described. Moreover, since the purification device 3C includes the same elements or structures as the purification devices 3A and 3B according to the first and second embodiments, the same elements and structures are denoted by the same reference numerals and detailed. Description is omitted.

  The purification device 3C includes a sewage storage tank 11C having functions as an oil content floating separation means, a solid content sedimentation separation means, and a solubilization means. The storage tank 11C includes an introduction pipe (introduction section) 13 that receives sewage, a tank body 15C that stores sewage, and a discharge pipe (discharge section) 17 that discharges primary treated water from the tank body 15C.

  The tank body 15C is divided into two (a plurality of) storage chambers, that is, an upstream chamber 15a and a downstream chamber 15c by a partition wall 55. The bottom portion 57 of the tank body 15C is separated from the upstream chamber 15a and the downstream by the partition wall 55. The chambers 15c are divided as bottom portions 57a and 57b. The partition wall 55 that partitions the upstream chamber 15a and the downstream chamber 15c is formed with a communication hole 59 that communicates the upstream chamber 15a and the downstream chamber 15c.

  In the tank body 15C of the storage tank 11C, the sewage from the introduction pipe 13 is introduced into the upstream chamber 15a, and further gently flows toward the downstream chamber 15c while passing through the communication hole 59, and is kept stationary in the process. The At that time, the oil and fat F in the sewage is floated and separated in the upstream chamber 15a and the downstream chamber 15c, respectively, and the coarse solid S is settled and separated. The oil layer and the sedimentation separation layer generated in the upstream chamber 15a and the downstream chamber 15c are the thickest in the upstream chamber 15a and the thinnest in the downstream chamber 15c.

  The tank body 15C includes a bottom portion 57 that forms a solubilizing means, and a side wall 25. The primary treated water from which the organic component in the coarse solid S is eluted by the solubilizing means is discharged from the discharge pipe 17 and supplied to the solid-liquid separation device 5 through the primary treated water discharge line 27 provided with a transfer pipe. Is done.

  According to the sewage treatment apparatus 1C according to the present embodiment, the same effect as the sewage treatment apparatuses 1A and 1B according to the first or second embodiment, that is, the oil and fat content F that overloads the membrane separation apparatus 9, In addition, the solid content S is removed by the purification device 3B in the previous stage. Furthermore, the purification device 3C includes a storage tank 11C that functions as a solids sedimentation separation unit and a solubilization unit, and is necessary for biologically removing nitrogen compounds and phosphorus compounds in the biological treatment device 7. The organic component can be supplemented by solubilization of the coarse solid S. As a result, by using the biological treatment device 7 and the membrane separation device 9 together, organic pollutants, nitrogen compounds, and phosphorus compounds are effectively removed, and the load on the membrane separation device 9 is reduced, resulting in high quality. Reclaimed water can be obtained stably.

  Furthermore, according to the sewage treatment apparatus 1C according to the third embodiment, since the tank body 15C of the storage tank 11C is partitioned by the partition wall 55, it can be expected to remove the remaining contaminants in the sewage W, and is disposed in the subsequent stage. It is possible to reduce the load on the solid-liquid separator 5 that is being operated.

  Furthermore, since the introduction pipe 13 of the purification device 3C is provided in the upstream chamber 15a which is a storage chamber different from the downstream chamber 15c in which the discharge pipe 17 is provided, the introduction pipe 13 is introduced from the introduction pipe 13 in the downstream chamber 15c. Therefore, it becomes difficult to be influenced by the flow of sewage, and thus it is easy to keep the sewage in a stationary state in the downstream chamber 15c.

Hereinafter, the present embodiment will be described more specifically with reference to examples. However, the scope of the present invention is not limited to the following examples.
[Example]

Raw water (sewage) having the following water quality was treated by the sewage treatment apparatus (see FIG. 2) according to the first embodiment described above.
(Raw water quality: before purification by purification equipment)
Solubility BOD: 100mg / L
TP: 4 mg / L
TN: 37 mg / L

The processing conditions such as the raw water flow rate, the residence time of each tank, and the sludge mixed liquid return amount were as follows.
(Processing conditions)

Raw water flow rate: 15m ³ / hr
Purification device residence time: 8 hr
Anaerobic tank residence time: 1.5 hr
Oxygen tank retention time: 3 hr
Aerobic tank residence time: 4 hr
Return amount of sludge mixture to anaerobic tank: 15 m ³ / hr
Return amount of sludge mixture to oxygen-free tank: 30m ³ / hr
Activated sludge concentration in anaerobic tank: 5,000 mg / L
Activated sludge concentration in anoxic tank: 7,500 mg / L
Activated sludge concentration in the aerobic tank: 10,000 mg / L
A hollow fiber MF membrane module (Asahi Kasei Chemicals Corporation Microza MUNC-620A) was used as the separation membrane.
[Comparative example]

  An experiment was conducted under the same conditions as in this example, except that no purification device was provided, with the same configuration as in this example. The primary treated water flowing into the biological treatment apparatus 7 is the same as the raw water (sewage) coming out of the apartment house / factory. Table 1 shows a comparison of the raw water quality and the final treated water quality (reclaimed water obtained by the membrane separation device) according to the present example having the purification device and the comparative example without the purification device. As shown in Table 1, in this embodiment, the soluble BOD, TN, and TP in the primary treated water flowing into the biological treatment device 7 with respect to the raw water (sewage) by passing through the purification device. Both concentrations are high. This is because BOD, TN, and TP were eluted from the solids such as feces by the purification device. Thereby, compared with a comparative example, in a present Example, raw | natural water quality is adjusted so that the ratio of BOD: TN: TP may become an appropriate condition for performing biological treatment, and TN of final treated water is accompanied by it. : It turns out that the density | concentration of TP is falling. The biological treatment improvement effect by this sewage treatment equipment was confirmed.

  DESCRIPTION OF SYMBOLS 1A, 1B, 1C ... Sewage treatment device, 3A, 3B, 3C ... Purification device, 5 ... Solid-liquid separation means, 7 ... Biological treatment device, 9 ... Membrane separation device, 11A, 11B, 11C ... Reservoir Means, solids sedimentation and separation means, solubilization means), 13 ... introduction pipe (introduction part of the purification device), 15A, 15B, 15C ... tank body, 15a ... upstream chamber (reservoir chamber), 15c ... downstream chamber (reservoir chamber) ), 17 ... discharge pipe (discharge part of the purifier), 19, 20, 55 ... partition wall, 21, 24, 57 ... bottom (bottom part of the tank body), 22, 23, 59 ... communication holes, 25 ... side walls.

Claims (8)

A purification device that receives and purifies a part of the sewage flowing toward the sewer main line, and
A biological treatment apparatus for biologically removing organic pollutants, nitrogen compounds, and phosphorus compounds from the treated water obtained by the purification apparatus;
A membrane separation device for separating and removing turbidity from the biological treatment water obtained by the biological treatment device to obtain reclaimed water,
The purifying apparatus includes an oil flotation separating unit that floats and separates an oil component in the wastewater, a solid sedimentation separation unit that settles and separates a solid component in the wastewater, and a solid content that has been settled and separated by the solids sedimentation separation unit. And a solubilizing means for solubilizing and solubilizing the wastewater treatment apparatus.   The sewage treatment apparatus according to claim 1, wherein a residence time of the sewage in the solubilizing means is 1 hour or more and 24 hours or less.   The sewage treatment apparatus according to claim 1, wherein a residence time of the sewage in the solubilizing means is 2 hours or more and 8 hours or less.   Further comprising a solid-liquid separation device that physically separates and removes the residual impurities in the treated water obtained by the purification device, and supplies the treated water from which the residual impurities have been removed to the biological treatment device. The sewage treatment apparatus according to any one of claims 1 to 3. The purification device has the oil levitation separation means and the sewage storage tank functioning as the solids sedimentation separation means,
The storage tank includes an introduction part that receives the wastewater, a tank main body that floats and separates the oil from the wastewater while holding the wastewater in a stationary state, and sinks and separates the solid from the wastewater, and the oil And a discharge section for discharging the treated water from which the solid content has been separated from the tank body. The tank body has a bottom portion on which the solid content that settles and a side wall that is erected along the periphery of the bottom portion and holds the solid content,
6. The sewage treatment apparatus according to claim 5, wherein the solubilizing means is formed by the bottom part for retaining the solid content and the side wall.   The sewage treatment apparatus according to claim 5 or 6, wherein the storage tank includes a partition wall that divides the tank main body, and a communication hole that connects adjacent storage chambers with the partition wall interposed therebetween.   The introduction portion is provided in any one of the storage chambers divided by the partition wall, and the discharge portion is provided with the introduction portion of the plurality of storage chambers. The sewage treatment apparatus according to claim 7, wherein the sewage treatment apparatus is provided in the storage chamber different from the storage chamber.

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