JP2012096125A - Membrane-separation-type activated sludge process equipment and method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide membrane-separation-type activated sludge process equipment which carries out circulation of an aerobic tank, without reduction of the effective membrane separation area, with a uniform and stable flow rate of to-be-processed water required for washing of the surface of the membrane and a method for the equipment.SOLUTION: The membrane-separation-type activated sludge process equipment 10 includes an aerobic tank 12 treating target water 16 biologically and aerobically by using activated sludge 18 held within the tank, an air diffusion means 20 of supplying air required for the aerobic treatment and a membrane separation means 30 immersed in the aerobic tank 12. In the aerobic tank 12, there is formed a separation wall 50 dividing the membrane separation means 30 from the air diffusion means 20 vertically. The separation wall 50 has an upper opening 52 through which an ascending flow of the target water 16 produced in air diffusion by the air diffusion means 20 moves laterally under the water surface and flows into the side of the membrane separation means 30 and a lower opening 54 through which the ascending flow incoming from the upper opening 52 passes through the separation membranes of the membrane separation means 30 as a descending flow and flows out to the side of the air diffusion means 20.

Description

  The present invention relates to a membrane separation type activated sludge treatment apparatus in which a membrane separation means is immersed in an aerobic tank holding activated sludge, and a method therefor.

  A membrane separation type activated sludge treatment apparatus is used as an apparatus for efficiently removing organic substances, nitrogen, phosphorus and the like in water to be treated. FIG. 6 schematically shows this type of membrane separation type activated sludge treatment apparatus 100. The aerobic tank 102 is filled with water to be treated 108 that has flowed from the water to be treated inflow pipe 102a. In the aerobic tank 102, the activated sludge 109 is held at a high concentration in advance, and the membrane separation means 104 is immersed therein. As the membrane separating means 104, one having a structure in which a large number of rectangular flat membranes with separation membranes on both sides is arranged in parallel in a transverse direction at a narrow interval is generally employed. An air diffuser 106 is disposed below the membrane separator 104 and diffuses air supplied from the blower 106 a toward the membrane separator 106. The membrane separation means 104 is provided with a suction pump 104a for discharging the treated water that has permeated through the flat membrane to the outside of the apparatus in the middle of the discharge pipe 104b.

  In the above configuration, the water to be treated 108 that has flowed into the aerobic tank 102 is biologically aerobically treated by the activated sludge 109, and organic matter, nitrogen, phosphorus, and the like in the water to be treated 108 are removed. In the membrane separation means 104, membrane separation is performed by the suction force of the suction pump 104a, and the activated sludge 109 and the treated water are separated into solid and liquid. The treated water that has permeated the flat membrane is discharged out of the apparatus through the discharge pipe 104b. As a result, the activated sludge 109 stays in the aerobic tank 102, and the activated sludge is kept at a high concentration in the aerobic tank 12 together with the proliferation by the aerobic treatment.

Here, the aeration from the aeration means 106 has three purposes.
The first purpose is to keep the aerobic tank 102 aerobic. Since oxygen is consumed in the biological aerobic treatment by the activated sludge 109, oxygen can be replenished by aeration to maintain the dissolved oxygen concentration in the treated water 108 in the aerobic tank 102 high. .

  The second purpose is to wash the separation membrane of the membrane separation means 104. Activated sludge and various solids adhere to and accumulate on the membrane surface of the flat membrane by membrane separation, and if left as it is, the permeability of the separation membrane gradually decreases, so that aeration is performed for the purpose of cleaning the membrane surface. That is, air bubbles diffused from below the membrane separation means 104 rise by buoyancy. In the ascending process, a shearing force is applied to the film surface of the flat film, and the solid content adhered and deposited on the film surface can be peeled off.

  The third purpose is to form a circulation flow of the water to be treated 108 in the aerobic tank 102. Ascending force of the diffused air bubbles and the density difference between the gas-liquid mixed liquid and the external liquid in the intermembrane water channel are used as a driving force, and the upward flow of the water to be treated 108 is generated in the membrane separation means 104, and the membrane The treated water 108 is sucked from below the separating means 104. The to-be-processed water 108 pushed out above the membrane separation means 104 descends the flow path and is sucked again from below the membrane separation means 104. In the circulation process of the water to be treated 108, the water to be treated 108 and the activated sludge 109 are sufficiently mixed and brought into contact with each other, and the aerobic treatment with the activated sludge 109 proceeds actively.

  As described above, the membrane separation type activated sludge treatment apparatus 100 can simultaneously perform the aerobic treatment and the solid-liquid separation by the activated sludge 109 in the aerobic tank 102. For this reason, a sedimentation basin can be abbreviate | omitted compared with the activated sludge processing apparatus provided with the conventional sedimentation basin, and the compactness and high efficiency of an apparatus can be achieved.

  However, there are difficult problems to achieve the above three purposes of aeration. In order to achieve the first object, it is necessary to make the air bubbles to be diffused as fine as possible to increase the gas-liquid contact area per unit volume. However, when the air bubbles are made finer, the ascending force of the air bubbles decreases, and a sufficient shearing force cannot be applied to the membrane surface of the membrane separation means 104. For this reason, the cleaning effect of the film surface which is the second purpose is lowered. In addition, the formation of the circulation flow, which is the third purpose, becomes insufficient. On the contrary, if the air bubbles to be diffused are preferentially given priority for the second and third purposes, the dissolution efficiency of oxygen in the water to be treated 108 is lowered, and the efficiency of the aerobic treatment with activated sludge is also due to the lack of dissolved oxygen. There is a problem of lowering.

  Thus, there is a trade-off between the first objective and the second and third objectives regarding the size of the air bubbles to be diffused, and it is difficult to achieve the three objectives at the same time only by aeration. .

  In Patent Document 1, in order to solve the above problem, an aerobic tank for biologically aerobically treating the water to be treated with activated sludge held in the tank, and a membrane separation means immersed in the aerobic tank A membrane separation type activated sludge treatment apparatus comprising: a diffuser for diffusing air from below the membrane separation means; and a treated water discharge means for discharging treated water permeated by the membrane separation means. There is disclosed a configuration in which bubble refining means for refining air bubbles diffused from the air means and reaching the upper region of the membrane separation means with a rotating blade is disclosed.

Japanese Patent Laid-Open No. 2004-237202

  In the case of the above configuration, the circulation of the aerobic tank and the cleaning of the membrane separation means are performed by the coarse air bubbles before being refined, and then the air bubbles are refined to dissolve oxygen in the water to be treated. Therefore, the problem that the effective separation membrane area decreases when the area of the air bubbles in contact with the separation membrane decreases has not been solved. For this reason, it is necessary to increase the load of the suction pump downstream of the separation membrane. Will give a heavy load.

  Moreover, in the said structure, in order to obtain the flow velocity of the to-be-processed water for washing | cleaning, a great amount of aeration is required, and as a result, a great amount of electric power is required. In particular, when a large number of flat membranes are juxtaposed, it is very difficult to evenly diffuse the gaps between the membranes.

  Furthermore, the flow rate of water to be treated required for cleaning the membrane surface is determined by the amount of permeated water in the treated water. However, it is difficult to provide the necessary flow rate for air diffuser that is difficult to homogenize. Therefore, a great amount of power is required.

  Therefore, the present invention pays attention to the above-mentioned problems, and does not reduce the effective membrane separation area, but provides a flow rate of water to be treated necessary for uniform and stable washing of the membrane surface and circulates in the aerobic tank. An object is to provide a sludge treatment apparatus and method.

  In order to solve the above problems, a membrane separation type activated sludge treatment apparatus according to the present invention includes an aerobic tank for biologically aerobically treating water to be treated with activated sludge held in the tank, and the aerobic tank. Forming a downward flow that flows from above to below between the membranes of the membrane separation means from the membrane separation means immersed therein and the upward flow in the aerobic tank by the air supply supplying the air necessary for the aerobic treatment It is characterized by having an aeration means for making it possible.

Further, the membrane separation type activated sludge treatment apparatus according to the present invention supplies an aerobic tank for biologically aerobically treating the water to be treated with the activated sludge held in the tank, and air necessary for the aerobic treatment. A membrane separation type activated sludge treatment apparatus comprising an air diffuser and a membrane separator immersed in the aerobic tank, wherein the membrane separator and the air diffuser are vertically arranged in the aerobic tank. Forming a separation wall to be separated; a lower opening in which water to be treated on the membrane separation means side is sucked into the aeration means side by the upward flow generated by the diffusion of the aeration means on the separation wall; An upper opening is provided in which the upward flow flows as a downward flow from the diffusion means side to the membrane separation means side by discharging the water to be treated from the lower opening.
In this case, it is preferable that the air diffuser includes a fine air diffuser and a coarse air diffuser, and the coarse air diffuser is formed on the side of the separation wall.

  The membrane-separated activated sludge treatment method of the present invention comprises a membrane separator in which an aerobic tank is provided with an air diffuser, and after the aerobic treatment with the activated sludge retained in the aerobic tank, the treated water is subjected to membrane separation by the membrane separator The activated sludge treatment method, wherein the membrane separating means and the aeration means in the aerobic tank are separated, and an upward flow is generated in the aerobic tank by the aeration of the aeration means, The ascending flow is caused to flow from the upper part of the membrane separation means, lowered between the membranes, discharged from the lower part of the membrane separation means, and refluxed.

The membrane separation activated sludge treatment apparatus and method according to the present invention have the following effects.
First, since the air diffuser forms a downward flow that flows from the upper side to the lower side between the membranes of the membrane separation unit from the upward flow in the aerobic tank due to the air diffused to supply the air necessary for the aerobic treatment, Not only to suppress the accumulation of activated sludge on the separation membrane, but also to remove the activated sludge deposited on the separation membrane by the treated water and return the treated water and activated sludge to the aerobic tank for circulation. Become. Therefore, a uniform flow is applied to the membrane surface to facilitate filtration, and the separation membrane is washed more effectively than the case of aeration to prevent a decrease in the efficiency of membrane separation per unit area. It is possible to prevent a decrease in effective membrane area due to the above.

  Compared with the conventional washing with an upward flow (aeration and gas-liquid mixed phase flow of diffused water) of the diffused air by disposing the diffuser means below the membrane separation means, the downward flow of the present invention Since it is a liquid single-phase flow, the shearing force tends to be high, and the effect of improving the cleaning power can be obtained.

  Secondly, the air diffuser eliminates the need for air diffused by the air diffuser disposed below the conventional membrane separator. For this reason, the design specialized for the purpose of dissolving oxygen in to-be-processed water is possible. Therefore, since the supply of dissolved oxygen to the activated sludge is performed only with high-efficiency fine bubble aeration, the power required for the aeration can be reduced.

  Third, it is possible to change the upward flow velocity by the air diffuser according to the amount of membrane permeated water of the treated water, so that it is possible to save power and power, unlike the conventional case where air is constantly diffused. It is.

It is the figure which showed typically embodiment of the membrane separation type | formula activated sludge processing apparatus of this invention. It is explanatory drawing of the membrane separation type | formula activated sludge processing apparatus of this invention. It is a graph which shows the relationship between a sludge flow rate and a membrane permeated water amount. It is a figure which shows the structure outline of the modification 1 of a membrane separation type | formula activated sludge processing apparatus. It is a figure which shows the structure outline of the modification 2 of a membrane separation type | formula activated sludge processing apparatus. It is explanatory drawing of the conventional membrane separation type | formula activated sludge processing apparatus.

Embodiments of a membrane separation type activated sludge treatment apparatus and method of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram schematically showing an embodiment of a membrane separation type activated sludge treatment apparatus of the present invention. FIG. 2 is an explanatory view of the membrane separation type activated sludge treatment apparatus of the present invention. As shown in FIG. 1, the membrane separation type activated sludge treatment apparatus 10 includes an aerobic tank 12, an air diffusion means 20, a membrane separation means 30, and a separation wall 50 as main components.

  The aerobic tank 12 is a water tank filled with the water to be treated 16 supplied via the inflow pipe 14, and a predetermined amount of activated sludge 18 is held in the tank. The activated sludge 18 contains complex microorganisms. Examples of complex microorganisms include nitrifying bacteria, denitrifying bacteria, and anaerobic ammonia oxidizing bacteria. Further, pure strains include, for example, nitrifying bacteria, denitrifying bacteria, anaerobic ammonia bacteria, blue-green-degrading bacteria, PCB-degrading bacteria, dioxin-degrading bacteria, and environmental hormone-degrading bacteria.

  In the aerobic tank 12, an air diffuser 20 capable of releasing fine air bubbles (not shown) is disposed for the purpose of dissolving dissolved oxygen in the water to be treated 16. The air diffuser 20 comprises a blower 22 and an air diffuser 24, supplies air from the blower 22, and discharges fine air bubbles (not shown) from the air diffuser 24 to increase the dissolved oxygen concentration in the aerobic tank 12. Can be maintained. Moreover, the activated sludge 18 hold | maintained at the aerobic tank 12 can perform the aerobic process which makes ammonia contained in the to-be-processed water 16 nitrate nitrogen, breathing dissolved oxygen. When the aerobic tank 12 is viewed in plan, the aeration means 20 of the present invention is arranged at a location where a membrane separation means 30 described later is not arranged above.

  A membrane separation means 30 is disposed in the aerobic tank 12 and is immersed in the water to be treated 16. The membrane separation means 30 is formed by arranging a plurality of rectangular flat membranes 32 each having a separation membrane on both sides at regular intervals. The gap between adjacent flat membranes is about 4 to 10 mm. The side surfaces on both sides of each flat membrane 32 are aligned, and a plurality of flat membranes 32 are integrated by joining side plates to the side surfaces. Thereby, the side surface direction of the flat film 32 is sealed, the upper end and the lower end are opened (upper opening 38, lower opening 39), and a plurality of gaps formed between the flat films 32 have a rectangular cross-sectional shape. The outside of each flat membrane 32 is in contact with the water to be treated 16, and the inside is connected to the treated water suction pump 42 via the discharge pipe 40. By sucking with the treated water suction pump 42, a pressure difference between the outside and inside of the flat membrane 32 is generated, and the activated sludge 18 and the treated water are separated from the treated water 16 into solid and liquid, and the treated water is inside the flat membrane 32. And is discharged out of the system through the treated water suction pump 42. At this time, the activated sludge is deposited on the separation membrane of the flat membrane 32. The separation efficiency of the separation membrane per unit area decreases as the deposition thickness increases.

  A separation wall 50 is provided between the air diffusion means 20 and the membrane separation means 30 in the aerobic tank 12. The separation wall 50 is a wall that divides the diffuser 20 and the membrane separator 30 disposed in the aerobic tank 12 in the vertical direction, and has openings (an upper opening 52 and a lower opening, respectively) below and near the bottom of the water surface in the tank. 54). The upper opening 52 is an opening through which the upward flow caused by the air diffused by the air diffuser 20 moves to the side below the water surface and flows from the air diffuser 20 side to the membrane separator 40 side, and below the water surface of the aerobic tank 12. Located in the vicinity. On the other hand, the lower opening 54 is an opening through which the downward flow that has descended between the membranes of the membrane separation means 30 is discharged, and is provided near the bottom surface of the aerobic tank 12.

  Further, as shown in FIG. 2, the membrane separation means 30 is installed at the center of the aerobic tank 12, and the air diffusion pipes 24 of the air diffusion means 20 are arranged on both sides of the aerobic tank 12 so as to sandwich the membrane separation means 30. Alternatively, a separation wall 50 having upper and lower openings 52 and 54 may be attached.

The sludge treatment method of the membrane separation type activated sludge treatment apparatus having the above configuration will be described below.
In the membrane separation activated sludge treatment apparatus 10 having the above-described configuration, the water to be treated 16 flowing from the inflow pipe 14 of the water to be treated 16 is stretched into the aerobic tank 12. In the aerobic tank 12, activated sludge 18 is held in high concentration in advance. Further, the inside of the aerobic tank 12 is divided into two by the separation wall 50, and the aeration means 20 and the membrane separation means 30 are arranged respectively. The membrane separation means 30 has a structure in which a large number of rectangular flat membranes 32 having separation membranes on both sides are juxtaposed in a lateral direction at a narrow pitch. The gap between the adjacent flat membranes 32 is 4 to 10 mm, and the membrane separation process is performed in the course of the treated water 16 and the activated sludge 18 passing through this gap. At this time, the suction pump 42 sucks the pressure difference between the outside and the inside of the flat membrane 32 to separate the activated sludge 18 and the treated water from the water 16 to be treated, and the treated water is separated into the flat membrane 32. And is discharged out of the treatment tank.

  On the other hand, when air is diffused into the aerobic tank 12 by the air diffuser 20, dissolved oxygen necessary for biological treatment held in the aerobic tank 12 can be supplied. Further, when air is diffused by the air diffuser 12, air rises, in other words, an upward flow of the water to be treated 16 and the activated sludge 18 is generated due to the air lift effect. The upward flow of the present invention has a high flow velocity that gives a sufficient shearing force in the flow direction of the separation membrane surface of the membrane separation means 30. In the intermembrane water channel of the membrane separation means 30, the water to be treated that flows in the horizontal direction with respect to the membrane surface penetrating into the membrane from the membrane surface, and the water to be treated that flows downward from above along the membrane surface of the separation membrane. There are two directions of flow. The flow of water to be treated flowing from above to below along the membrane surface acts as a shearing force for stripping off the activated sludge adhering to the membrane surface.

  In the aerobic tank 12 of the present embodiment, the inside of the intermembrane water channel of the separation membrane is a single-phase portion of the water to be treated, and the inside of the tank on the air diffusion means 20 side outside thereof is a gas-liquid mixed phase of the water to be treated and the air diffused. Part. The gas-liquid mixed phase portion has a lower specific gravity than the single phase portion. The upward flow can be generated by giving a density difference between the single phase portion and the gas-liquid mixed phase portion. Specifically, the density difference can be adjusted by changing the opening area of the opening of the separation wall 50, the air space in the aerobic tank 12, the amount of air diffused by the air diffuser 20, and the like.

  Due to the upward flow generated by the density difference between the gas-liquid mixed phase portion and the single phase portion, a flow of water to be treated sucked into the diffuser means 20 side is generated below the single phase portion (membrane separation means 20) (arrow A). . Further, above the single-phase portion, the water to be treated flows as a downward flow from the aeration means side to the membrane separation means side (arrow B) due to the downward flow caused by the discharge of the water to be treated. Thus, the upward flow moves sideways when it rises below the surface of the water in the tank. The upward flow that has moved laterally flows from the upper opening 52 of the separation wall 50 toward the membrane separation means 30 side. At this time, the air bubbles are discharged to the outside of the tank and become a flow of treated water and activated sludge. The upward flow of the water to be treated 16 and the activated sludge 18 flowing from the upper opening 52 becomes a downward flow at the upper opening 38 of the membrane separation means 30. This downward flow becomes a flow toward the lower opening 39 between the membranes of the membrane separation means 30, and the flow direction is reversed. The passage of the downward flow not only suppresses the accumulation of activated sludge on the separation membrane, but also causes the treated water 16 to peel off the activated sludge accumulated on the separation membrane. The downward flow is sucked (discharged) from the lower opening 54 to the diffuser means 20 side, becomes an upward flow again, and returns inside the aerobic tank 12.

  As a result, the separation membrane is washed more effectively than in the case of the upward flow by the conventional air diffuser to prevent a decrease in the efficiency of the membrane separation per unit time and unit area, and the effective membrane area due to the air diffused bubbles Can be prevented, and continuous and stable filtration can be realized.

The air diffuser 20 can be designed specifically for the purpose of dissolving oxygen in the water 16 to be treated. Therefore, the supply of dissolved oxygen to the activated sludge 18 is performed only by aeration with high-efficiency fine air bubbles, so that the power required for the aeration can be reduced.
Furthermore, since it is possible to change the flow rate of the water to be treated 16 according to the amount of permeated water of the treated water, it is possible to save power, unlike the conventional case where the aeration is always continued.

  Further, the activated sludge flow rate necessary for cleaning the activated sludge 18 attached to the separation membrane surface is provided by the downflow formed by the treated water 16 generated by the aeration necessary for biological treatment and the upflow of the activated sludge 18. Therefore, it is not necessary to provide a conventional air diffuser for cleaning.

  By the way, the present inventor investigated the amount of membrane separation water per unit time / unit area of the separation membrane with respect to the speed of the water to be treated on the separation membrane surface. FIG. 3 is a graph showing the relationship between the sludge flow rate and the amount of membrane permeated water. In the figure, the horizontal axis represents the membrane surface sludge speed (m / s), and the vertical axis represents the average flux (m / d). As shown in the figure, as the membrane surface sludge speed is increased, the average flux increases, that is, the amount of filtered water increases. Therefore, when the speed is increased, deposition of activated sludge on the separation membrane is suppressed or deposited. It can be interpreted that the separation membrane was peeled off by the fast flow rate of the water to be treated.

  FIG. 4 is a diagram showing a schematic configuration of Modification 1 of the membrane separation type activated sludge treatment apparatus. The configuration of the membrane-separated activated sludge treatment apparatus 10A according to Modification 1 and the configuration different from the membrane-separated activated sludge treatment apparatus 10 shown in FIG. Other configurations are the same as those of the membrane separation type activated sludge treatment apparatus 10 of FIG. 1, and detailed description thereof is omitted.

  As shown in FIG. 4, the air diffuser 20 </ b> A of the membrane-separated activated sludge treatment apparatus 10 </ b> A according to Modification 1 includes a fine air diffuser 26 and a coarse air diffuser 28. The fine air diffuser 26 and the coarse air diffuser 28 are each connected to the blower 22 via a pipe.

  The fine air diffuser 26 is configured to allow fine diffuser with high oxygen dissolution efficiency. On the other hand, the coarse air diffuser 28 is configured to be able to diffuse bubbles (air) larger than the diffused bubbles generated by the fine air diffuser 26. The coarse air diffuser 28 is formed on the side of the separation wall 50 in the aerobic tank 12 rather than the fine air diffuser 26.

  According to the configuration of the first modification, the coarse air diffuser 28 capable of diffusing coarse bubbles is disposed at the lower side portion of the separation wall 50. Therefore, the rising flow velocity due to the coarse bubbles is increased, and the air lift effect is achieved. As a result, the descending flow velocity of the descending flow due to the ascending flow of the water to be treated 16 and the activated sludge 18 can be increased. Therefore, not only the activated sludge is prevented from accumulating on the separation membrane, but also the activated sludge deposited on the separation membrane is easily peeled off by the water to be treated.

  FIG. 5 is a diagram showing a schematic configuration of Modification 2 of the membrane separation type activated sludge treatment apparatus. The configuration of the membrane-separated activated sludge treatment apparatus 10B of Modification 2 and the configuration different from the membrane-separated activated sludge treatment apparatus 10A shown in FIG. 4 are the configurations of the aeration means. Other configurations are the same as those of the membrane separation type activated sludge treatment apparatus 10, and detailed description thereof is omitted.

  As shown in FIG. 5, in addition to the fine air diffuser 26 and the coarse air diffuser 28, the air diffuser 20B of the membrane separation activated sludge treatment apparatus 10B according to the modified example 2 is arranged below the membrane separator 30. A second coarse air diffuser 29 is attached to the bottom of the aerobic tank 12. Similarly to the fine air diffuser 26, the second coarse air diffuser 29 is also connected to the blower 22 via a pipe.

  According to the configuration of the first modification, when the filtration by the membrane separation unit 30 is stopped, the second coarse bubble diffusion unit 29 installed at the lower part of the membrane separation unit 30 is diffused, On the other hand, the activated sludge 18 that forms an upward flow and adheres to the separation membrane can be washed.

DESCRIPTION OF SYMBOLS 10 ......... Membrane separation type activated sludge processing apparatus, 12 ......... Aerobic tank, 14 ......... Inlet pipe, 16 ......... Water to be treated, 18 ......... Activated sludge, 20 ......... Air diffuser, 22 ......... Blower, 24 ......... Air diffuser, 26 ......... Fine air diffuser, 28 ......... Coarse air diffuser, 29 ......... Second coarse air diffuser, 30 ......... Membrane separation means 32... Flat membrane 38 ... upper opening 39 39 lower opening 50 separation wall 52 upper opening 54 lower opening 100 Membrane-separated activated sludge suction device 102... Aerobic tank 104 104 Membrane separation means 106 Air diffuser 108 Water to be treated 109 Activated sludge

Claims (4)

An aerobic tank for biologically aerobically treating the water to be treated with activated sludge retained in the tank;
Membrane separation means immersed in the aerobic tank;
Aeration means for forming a downward flow flowing from above to below between the membranes of the membrane separation means from the upward flow in the aerobic tank by the air supply for supplying air necessary for the aerobic treatment;
A membrane separation type activated sludge treatment apparatus characterized by comprising: An aerobic tank for biologically aerobically treating the water to be treated with activated sludge retained in the tank;
Aeration means for supplying air necessary for the aerobic treatment;
Membrane separation means immersed in the aerobic tank;
In the membrane separation type activated sludge treatment equipment equipped with
Forming a separation wall that vertically separates the membrane separation means and the aeration means in the aerobic tank;
In the separation wall,
A lower opening through which the water to be treated on the membrane separation means side is sucked into the aeration means side by the upward flow generated by the aeration of the aeration means;
An upper opening through which the upward flow flows as a downward flow from the diffuser means side by discharging the water to be treated from the lower opening;
A membrane-separated activated sludge treatment apparatus characterized by comprising:   The membrane separation type according to claim 2, wherein the air diffuser includes a fine air diffuser and a coarse air diffuser, and the coarse air diffuser is formed on a side of the separation wall. Activated sludge treatment equipment. A membrane separation type activated sludge treatment method comprising aeration means in an aerobic tank, after aerobic treatment with activated sludge held in the aerobic tank, and membrane separation of treated water by membrane separation means,
Dividing the membrane separation means and the aeration means in the aerobic tank,
By generating an upward flow in the aerobic tank by the air diffused by the air diffuser,
Allowing the upward flow to flow from above the membrane separation means,
A membrane separation activated sludge treatment method, wherein the membrane is lowered, discharged from the lower part of the membrane separation means, and refluxed.

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