JP6268660B1 - Biological treatment apparatus, biological treatment method, and program - Google Patents

Abstract

Even when fouling progresses, the flow rate of permeated water is stably secured. [MEANS FOR SOLVING PROBLEMS] A biological treatment water tank (11), a membrane separation device (1) having a tubular filtration membrane having a single layer structure in which hydrophilic monomers are copolymerized, and a pressure pump (21) for supplying supply water (W3) to the membrane separation device (1). A suction pump 22 for sucking the permeated water PW from the membrane separation device 1, a back pressure adjusting device 23 for adjusting the back pressure in the permeation side space, a transmembrane differential pressure measuring device 14 for measuring the transmembrane pressure difference, and a membrane The pressure pump 21, the suction pump 22, and the control device 13 for controlling the back pressure adjusting device 14 based on the inter-pressure difference, and the control device 13 is configured to increase the transmembrane pressure difference to a predetermined value or more. When the limit of the back pressure adjusting unit 13a for reducing the back pressure and the adjustment range of the back pressure adjusting device is reached, one of the pressurizing pump and the suction pump is controlled, and the pressurizing force of the pressurizing pump and the suction pump are controlled. A setting variable that increases one of the suction force and the back pressure. And part 13b, to provide a biological treatment apparatus 100 having a. [Selection] Figure 1

Description

  The present invention relates to a biological treatment apparatus, a biological treatment method, and a program.

When organic wastewater such as human waste is treated, it is the mainstream to use membrane separation such as MF (microfiltration) and UF (ultrafiltration) for solid-liquid separation.
As a membrane separation device, there is known a device that includes a casing and a plurality of tubular filtration membranes (hollow fiber membranes) accommodated in the casing, and performs filtration while circulating supply water inside the tubular filtration membrane. (For example, refer to Patent Document 1). In a biological treatment apparatus that includes such a membrane separation apparatus and performs biological treatment of organic wastewater, the permeated water that has permeated through the tubular filtration membrane is sucked by a suction pump, for example, stored in a storage tank and used as appropriate. The

JP 2013-052338 A

  By the way, in a membrane separation apparatus using a tubular filtration membrane, fouling in which fine particles adhere to the membrane surface proceeds by continuously performing filtration. In the conventional biological treatment apparatus, since the flow rate of permeated water decreases due to the progress of fouling, there is a problem that it is difficult to stably secure the flow rate of permeated water.

  An object of the present invention is to provide a biological treatment apparatus, a biological treatment method, and a program capable of stably ensuring the flow rate of permeated water even when fouling progresses in a tubular filtration membrane.

  According to the first aspect of the present invention, the biological treatment apparatus is supplied with a biological treatment water tank that treats organic matter contained in the water to be treated, a casing, and supply water that flows out of the casing from the biological treatment water tank. And a tubular filtration membrane having a single layer structure in which a hydrophilic monomer is copolymerized, and is partitioned into a concentrated side space and a permeate side space in which permeated water separated from the supply water is accommodated A pressure pump for supplying the supply water to the concentration side space, a suction pump for sucking the permeate from the permeation side space, a back pressure adjusting device for adjusting a back pressure of the permeation side space, A return line for returning the concentrated water discharged from the membrane separator to the biological treatment water tank, a transmembrane differential pressure measuring device for measuring a transmembrane differential pressure between the concentrated side space and the permeate side space, and the intermembrane Based on the differential pressure, the pressure pump , The suction pump, and a control device that controls the back pressure adjusting device, and the control device controls the back pressure adjusting device when the transmembrane pressure difference increases to a predetermined value or more. When the limit of the back pressure adjusting unit that reduces the back pressure and the adjustment range of the back pressure adjusting device is reached, at least one of the pressurizing pump and the suction pump is controlled to apply the pressurizing pump. A setting changing unit that increases at least one of the pressure and the suction force of the suction pump and controls the back pressure adjusting device to increase the back pressure.

According to such a configuration, by reducing the back pressure of the tubular filtration membrane based on the transmembrane pressure difference, even when the transmembrane pressure difference increases due to fouling, the movable range of the back pressure adjustment device is used. The flow rate of the permeated water can be adjusted.
In addition, when the upper limit of the movable range of the back pressure adjusting device is reached, at least one of the applied pressure and the suction force is increased, and the back pressure is increased to allow transmission through the movable range of the back pressure adjusting device again. The flow rate of water can be adjusted.
In addition, since the tubular filtration membrane has hydrophilicity, the flow rate of the supplied water supplied to the concentration side space is low, and the permeated water can be taken even when the pressure of the supplied water is low.

  The said biological treatment apparatus WHEREIN: The said setting change part may perform control which increases the suction force of the said suction pump, after increasing the applied pressure of the said pressurization pump and controlling to an upper limit.

  According to such a configuration, the effect of cleaning the tubular filtration membrane can be produced by increasing the pressure applied by the pressure pump and increasing the membrane surface flow velocity.

  The said biological treatment apparatus WHEREIN: The said control apparatus may have a washing | cleaning control part which wash | cleans the said tubular filtration membrane, after increasing the suction force of the said suction pump and controlling to an upper limit.

  According to such a configuration, the pressure and suction force can be reduced again by cleaning the tubular filtration membrane. In addition, the number of cleanings can be reduced by performing cleaning after controlling both the pressing force and the suction force to the upper limit.

  In the biological treatment apparatus, the return line includes a branch line that supplies the concentrated water between the biological treatment water tank and the membrane separation device, and is provided on the downstream side of the branch line and flows through the return line. A second flow rate adjusting valve that adjusts the flow rate of the concentrated water.

  According to such a configuration, the flow rate of the concentrated water introduced into the biological treatment water tank can be adjusted.

  According to the second aspect of the present invention, the biological treatment method includes a feed water flowing out from the biological treatment water tank to a concentration side space which is one side of a tubular filtration membrane having a single layer structure in which hydrophilic monomers are copolymerized. Pressurizing step for supplying pressure, sucking step for sucking the permeated water from the permeate side space which is the other side of the tubular filtration membrane, and concentrate water discharged from the concentrating side space to the biological treatment water tank A returning step for returning, a back pressure adjusting step for reducing a back pressure in the permeation side space, when a transmembrane pressure difference between the concentration side space and the permeation side space is increased to a predetermined value or more; A setting changing step of increasing at least one of the pressure of the supply water and the suction force of the permeated water and increasing the back pressure when the limit of the adjustment range is reached.

  According to the third aspect of the present invention, the program includes a biological treatment water tank that treats organic matter contained in the water to be treated, a casing, and a concentration that is supplied with supply water that flows out of the casing from the biological treatment water tank. A membrane separation device having a side wall and a tubular filtration membrane having a single-layer structure in which a hydrophilic monomer is copolymerized and partitioned into a permeation side space in which permeated water separated from the supply water is accommodated, A pressure pump for supplying the supply water to the concentration side space; a suction pump for sucking the permeate from the permeation side space; a back pressure adjusting device for adjusting a back pressure in the permeation side space; and the membrane separation A biological treatment apparatus comprising: a return line for returning concentrated water discharged from the apparatus to the biological treatment water tank; and a transmembrane differential pressure measuring device for measuring a transmembrane differential pressure between the concentration side space and the permeation side space. Control device When the transmembrane pressure difference increases to a predetermined value or more on the computer, the back pressure adjustment device is controlled to decrease the back pressure, and when the adjustment range of the back pressure adjustment device is reached, Controlling at least one of the pressure pump and the suction pump to increase at least one of the pressurizing force of the pressurizing pump and the suction force of the suction pump, and controlling the back pressure adjusting device to control the back pressure It is a program for increasing.

According to the present invention, by reducing the back pressure of the tubular filtration membrane based on the transmembrane pressure difference, the permeated water can be used by using the movable range of the back pressure adjusting device even when the transmembrane pressure difference is increased by fouling. The flow rate can be adjusted.
In addition, when the upper limit of the movable range of the back pressure adjusting device is reached, at least one of the applied pressure and the suction force is increased, and the back pressure is increased to allow transmission through the movable range of the back pressure adjusting device again. The flow rate of water can be adjusted.

It is a schematic block diagram of the biological treatment apparatus of 1st embodiment of this invention. It is a schematic sectional drawing of the membrane separator of 1st embodiment of this invention. It is a flowchart explaining control I of the biological treatment method of the first embodiment of the present invention. It is a flowchart explaining control II of the biological treatment method of 1st embodiment of this invention. It is a flowchart explaining control III of the biological treatment method of the first embodiment of the present invention. It is a schematic sectional drawing of the membrane separator of the modification of 1st embodiment of this invention. It is a schematic perspective view of the membrane separator of 2nd embodiment of this invention. It is a schematic sectional drawing of the membrane separator of 2nd embodiment of this invention. It is a perspective view of the reinforcement member of 2nd embodiment of this invention. It is the side view which looked at the reinforcement member of 2nd embodiment of this invention from the axial direction of the reinforcement member. It is a perspective view of the reinforcement member of 3rd embodiment of this invention.

[First embodiment]
Hereinafter, a biological treatment apparatus, a biological treatment method, and a program according to a first embodiment of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 1, the biological treatment apparatus 100 of the present embodiment includes: a biological treatment water tank 11 that treats organic matter contained in water to be treated W1 (organic wastewater including human waste and septic tank sludge); The raw water tank 12 in which the flowing-out supply water W2 is accommodated, the membrane separation device 1 for separating the supply water W3 supplied from the raw water tank 12 into the permeated water PW and the concentrated water W4, and the flow rate of the permeated water PW (flow path) A first flow rate adjusting valve 23 (back pressure adjusting device) for adjusting the resistance), a storage tank 20 for storing the permeated water PW, a return line 19 for returning the concentrated water W4 to the biological treatment water tank 11, and a control device 13. It is equipped with.

  The control device 13 controls each part of the biological treatment apparatus 100 and executes various functions. The control device 13 is configured, for example, by a CPU (Central Processing Unit) provided in the biological treatment device 100 reading out and executing a program from the storage unit.

As shown in FIG. 2, the membrane separation device 1 includes a casing 2, a concentration side space S that is the casing 2 on one side of the tubular filtration membrane 3, and a permeation side space P that is the other side of the tubular filtration membrane 3. And a tubular filtration membrane 3 partitioned into two. Supply water W3 is supplied to the concentration side space S, and permeate PW separated from the supply water W3 is accommodated in the permeate side space P.
The membrane separation device 1 is a device that takes out permeated water PW from the supply water W3 using a method of filtering while circulating the supply water W3 inside a plurality of tubular filtration membranes 3.

  As shown in FIG. 1, the biological treatment apparatus 100 pressurizes the supply water W3 supplied from the raw water tank 12 (supply water W2 flowing out from the biological treatment water tank 11) and supplies it to the concentration side space S of the membrane separation apparatus 1. And a suction pump 22 for sucking the permeation side space P of the membrane separation device 1.

  The pressurizing pump 21 has a function of changing the applied pressure by controlling the number of rotations to change the membrane surface flow rate (the speed at which the supply water W3 flows inside the tubular filtration membrane 3). The movable range of the pressurizing pump 21 of the present embodiment is 0.15 m / s to 0.60 m / s when converted in terms of the membrane surface flow velocity. It is not preferable to operate the pressurizing pump 21 outside this movable range with respect to the specification of the tubular filtration membrane 3 of the present embodiment.

  The suction pump 22 has a function of changing the suction force from the transmission side space P by controlling the rotational speed. The lower limit frequency of the suction pump 22 of this embodiment is 6 Hz, and the upper limit frequency is 60 Hz. Thereby, the suction pump 22 can arbitrarily change the pressure in the transmission side space P.

  The biological treatment water tank 11 decomposes and removes BOD, nitrogen compounds and the like in the liquid by the action of nitrifying bacteria and denitrifying bacteria, for example. The biological treatment water tank 11 is supplied with the treated water W <b> 1 through the first line 15. The biological treatment water tank 11 and the raw water tank 12 are connected by a second line 16.

The raw water tank 12 and the membrane separation device 1 are connected via a supply line 17. The pressure pump 21 is provided in the supply line 17. The feed water W3 discharged from the raw water tank 12 is supplied to the concentration side space S of the membrane separation device 1 while being pressurized by the pressurizing pump 21.
The supply line 17 is provided with a first flow meter 25 for measuring the flow rate of the supply water W3 flowing through the supply line 17, and a first pressure gauge 26 for measuring the pressure of the supply water W3 flowing through the supply line 17. Yes.

  The permeated water PW separated from the membrane separation device 1 is introduced into the permeated water line 18. The permeate line 18 is connected to the storage tank 20. The first flow rate adjustment valve 23 and the suction pump 22 are provided in the permeate line 18. The first flow rate adjusting valve 23 of the present embodiment is provided on the downstream side of the suction pump 22, but is not limited thereto. The first flow rate adjustment valve 23 may be provided on the upstream side of the suction pump 22.

  The first flow rate adjusting valve 23 functions as a back pressure adjusting device that adjusts the flow resistance of the permeated water PW flowing through the permeated water line 18 to adjust the back pressure in the permeate side space P of the tubular filtration membrane 3. For example, when the opening degree of the first flow rate adjustment valve 23 is set to 20%, the back pressure in the transmission side space P is increased, and when the opening degree of the first flow rate adjustment valve 23 is set to 100%, the transmission side space is set. The back pressure of P becomes small. By controlling the opening of the first flow rate adjusting valve 23 in the direction of reducing the opening, the back pressure of the permeation side space P can be increased. By controlling the opening degree of the first flow rate adjusting valve 23 to increase, the back pressure in the permeate space P can be reduced.

  The permeate line 18 includes a second flow meter 27 that measures the flow rate of the permeate PW that flows through the permeate line 18 and a second pressure gauge 28 that measures the pressure of the permeate PW that flows through the permeate line 18. Is provided.

  The concentrated water W4 separated from the permeated water PW and discharged from the membrane separation device 1 is introduced into the return line 19 in the whole amount excluding excess sludge, and at least a part thereof is returned to the biological treatment water tank 11. The supply water W2 that has flowed out of the biological treatment water tank 11 returns to the biological treatment water tank 11 via the raw water tank 12 and the membrane separation device 1. That is, the supply water W <b> 2 that has flowed out of the biological treatment water tank 11 circulates through a line that constitutes the biological treatment apparatus 100.

A siphon breaker 40 is provided in the return line 19. The siphon breaker 40 includes a branch pipe 41 and a valve 42.
A third pressure gauge 44 for measuring the pressure of the concentrated water W4 flowing through the return line 19 is provided on the return line 19 and between the membrane separation device 1 and the siphon breaker 40.

  The return line 19 has a branch line 45 that branches from the middle of the return line 19 and supplies the concentrated water W <b> 4 to the raw water tank 12. The raw water tank 12 is not necessarily provided. When the raw water tank 12 is not provided, the branch line 45 is connected to a line between the biological treatment water tank 11 and the pressure pump 21.

  On the return line 19, on the downstream side of the branch point D of the branch line 45, the second flow rate adjustment valve 24 that adjusts the flow rate of the concentrated water W <b> 4 supplied to the biological treatment water tank 11, and the biological treatment water tank 11. Is provided with a third flow meter 43 for measuring the flow rate of the concentrated water W4 supplied to the. The third flow meter 43 is provided on the downstream side of the second flow rate adjustment valve 24 (between the second flow rate adjustment valve 24 and the biological treatment water tank 11).

The pressure gauges 26, 28, 44 and the flow meters 25, 27, 43 are connected to the control device 13 via an electric signal cable.
The first pressure gauge 26, the second pressure gauge 28, and the third pressure gauge 44 function as the transmembrane pressure difference measuring device 14 that measures the transmembrane pressure difference of the membrane separation device 1. The controller 13 controls the pressure of the supply water W3 measured by the first pressure gauge 26, the pressure of the permeated water PW measured by the second pressure gauge 28, and the concentrated water W4 measured by the third pressure gauge 44. From the pressure, the transmembrane pressure difference of the membrane separator 1 is calculated.

The biological treatment apparatus 100 has a cleaning device 29 that cleans the tubular filtration membrane 3 of the membrane separation device 1. The cleaning device 29 may be a device that performs cleaning by physical cleaning, may be a device that performs cleaning by chemical cleaning, or may be a device that performs cleaning by using both.
The physical cleaning is a cleaning method in which cleaning is performed by a physical method such as back pressure cleaning, scrubbing, flushing, or ball cleaning. Chemical cleaning is a cleaning method in which cleaning is performed using an acid, an alkali, an oxidizing agent, a detergent, or the like.

  The control device 13 includes a pressurizing pump 21, a suction pump 22, a first flow rate adjusting valve 23, a second flow rate adjusting valve 24, based on the flow rate of the permeated water PW, the transmembrane pressure difference, the flow rate of the water to be treated W1, and the like. The cleaning device 29 and the like are controlled. The control device 13 includes a back pressure adjusting unit 13a that controls the first flow rate adjusting valve 23 (back pressure adjusting device) based on the flow rate of the permeated water PW and the transmembrane pressure difference, and, for example, the first flow rate adjusting valve 23 is movable. When the range reaches the limit, it includes a setting changing unit 13b that changes the setting of the pressurizing pump 21 and the like, and a cleaning control unit 13c that controls the cleaning device 29.

  The control device 13 has a function of adjusting the flow rate of the concentrated water W4 introduced into the biological treatment water tank 11. When the flow rate of the concentrated water W4 measured by the third flow meter 43 exceeds a predetermined value, the control device 13 is configured so that the flow rate of the concentrated water W4 introduced into the biological treatment water tank 11 is equal to or lower than the predetermined value. The second flow rate adjustment valve 24 is controlled. Thereby, a part of the concentrated water W4 is introduced into the branch line 45.

Next, details of the membrane separation apparatus 1 will be described.
As shown in FIG. 2, the casing 2 includes a casing body 4, a supply water introduction port 7 formed below the casing body 4, a concentrated water discharge port 8 formed above the casing body 4, and a casing body. 4 and the permeated water discharge port 9 formed in 4.

The casing body 4 has a cylindrical cylindrical portion 4a, a first conical portion 5 that closes the upper end of the cylindrical portion 4a, and a second conical portion 6 that closes the lower end of the cylindrical portion 4a. The 1st cone part 5 has comprised the taper shape gradually diameter-reduced as it goes upwards. The second conical portion 6 has a tapered shape that gradually decreases in diameter as it goes downward.
The membrane separation device 1 of the present embodiment is configured such that the supply water W3 introduced into the tubular filtration membrane 3 from below flows upward in the tubular filtration membrane 3.

The membrane separation device 1 includes a first partition wall 30 and a second partition wall 31 that divide the inside of the casing 2 into three spaces. A plurality of insertion holes 32 are formed in the first partition wall 30 and the second partition wall 31. The insertion hole 32 is a hole that penetrates the first partition wall 30 and the second partition wall 31 in the plate thickness direction. The inner diameter of the insertion hole 32 is slightly larger than the outer diameter of the tubular filtration membrane 3.
The plurality of tubular filtration membranes 3 extend in the axis A direction (vertical direction in the present embodiment) inside the casing 2, one end is connected to the first partition wall 30, and the other end is connected to the second partition wall 31. ing.

The first partition 30 is a plate-shaped member, and is fixed above the extending direction of the casing 2 (on the side of the first conical portion 5). A space surrounded by the casing main body 4, the first partition wall 30, and the first conical portion 5 is a first header space S1. The first header space S1 is a space above the first partition wall 30 in the internal space of the casing 2.
The second partition wall 31 is a plate-shaped member, and is fixed below the extending direction of the casing 2 (on the second conical portion 6 side). The space surrounded by the casing body 4, the second partition wall 31, and the second conical portion 6 is a second header space S2. The second header space S <b> 2 is a space below the second partition wall 31 in the internal space of the casing 2.

  A space surrounded by the casing body 4, the first partition wall 30, and the second partition wall 31 and on the outer peripheral side of the tubular filtration membrane 3 is a permeation side space P. The permeated water PW taken out from the plurality of tubular filtration membranes 3 is discharged into the permeate side space P and then introduced into the permeate line 18 through the permeate discharge port 9.

The feed water introduction port 7 is an opening that allows the outside of the casing 2 to communicate with the second header space S2. The feed water inlet 7 is formed in the second conical part 6 of the casing body 4.
The concentrated water discharge port 8 is an opening that allows communication between the outside of the casing 2 and the first header space S1. The concentrated water discharge port 8 is formed in the first conical portion 5 of the casing body 4.

  The permeate discharge port 9 is an opening that allows the outside of the casing 2 and the permeate side space P to communicate with each other. The permeate discharge port 9 is provided in the upper part of the cylindrical portion 4 a of the casing body 4.

The concentration side space S is a space into which the supply water W3 is introduced, and is a first header space S1, a filtration membrane inner space S3 that is a space on the inner peripheral side of the tubular filtration membrane 3, and a second header space S2.
The permeate side space P is a space in which the permeate water PW separated from the supply water W3 is accommodated.

One end of each tubular filtration membrane 3 is fixed to the inner peripheral surface of the insertion hole 32 after being inserted into the insertion hole 32 of the first partition wall 30. A space between the inner peripheral surface of the insertion hole 32 and the outer peripheral surface of the tubular filtration membrane 3 is sealed with a sealing material (not shown). As the sealing material, a material that has an initial viscosity and hardens with time, such as an epoxy resin or a urethane resin, is preferable.
The other end of each tubular filtration membrane 3 is fixed to the insertion hole 32 of the second partition wall 31 in the same manner as one end of the tubular filtration membrane 3.

The tubular filtration membrane 3 has a cylindrical shape and has a single-layer polymer filtration membrane in which a hydrophilic monomer is copolymerized on a single main constituent material.
That is, the polymer filtration membrane is formed of a single type of main material. That the main material is formed of one kind of material means that one kind of resin accounts for 50% by mass or more in the material (for example, resin) forming the polymer filtration membrane.
The fact that the main material is formed of one kind of material means that the property of the one kind of material dominates the properties of the constituent materials. Specifically, it means a material in which one kind of resin has 50 mass% to 99 mass%. However, when there is a support for supporting the membrane, the support may be the same material as the polymer membrane or a different material.

  The main materials that make up the polymer filtration membrane include polyolefin resins such as vinyl chloride resin, polysulfone (PS), polyvinylidene fluoride (PVDF), and polyethylene (PE), polyacrylonitrile (PAN), and polyether. Polymer materials such as sulfone, polyvinyl alcohol (PVA), and polyimide (PI) can be used.

  As a main material constituting the tubular filtration membrane 3, a vinyl chloride resin is particularly preferable. Examples of vinyl chloride resins include vinyl chloride homopolymer (vinyl chloride homopolymer), a copolymer of a monomer having an unsaturated bond copolymerizable with vinyl chloride monomer and vinyl chloride monomer, and vinyl chloride monomer in the polymer. Examples thereof include graft copolymers obtained by graft copolymerization, and (co) polymers composed of chlorinated vinyl chloride monomer units.

Examples of hydrophilic monomers include:
(1) A cationic group-containing vinyl monomer such as an amino group, an ammonium group, a pyridyl group, an imino group or a betaine structure and / or a salt thereof,
(2) Hydrophilic nonionic group-containing vinyl monomers such as hydroxyl groups, amide groups, ester structures, ether structures,
(3) Anionic group-containing vinyl monomer such as carboxyl group, sulfonic acid group, phosphoric acid group and / or salt thereof,
(4) Other monomers may be mentioned.

  The tube diameter of the tubular filtration membrane 3 can be appropriately selected depending on the properties of the supply water W3. For example, when the coarse fiber amount α is 200 mg / liter or less for the supply water W3, the inner diameter of the tubular filtration membrane 3 is 5 mm or less. When the coarse fiber amount α is larger than 200 mg / liter and smaller than 500 mg / liter, the inner diameter of the tubular filtration membrane 3 is 5 mm-10 mm, and when the coarse fiber amount α is 500 mg / liter or more, the inner diameter of the tubular filtration membrane 3 is It can be 10 mm or more. By selecting the tube diameter, blockage of the tubular filtration membrane 3 due to the coarse fibers can be suppressed.

Next, the operation of the biological treatment apparatus 100 of this embodiment will be described.
To-be-treated water W1 such as human waste is pretreated by a pretreatment facility (not shown) and then sent to the biological treatment water tank 11 through the first line 15. The treated water W1 is treated in the biological treatment water tank 11. Specifically, the organic substance contained in the for-treatment water W1 is decomposed by microorganisms.
Next, the supply water W <b> 2 flowing out from the biological treatment water tank 11 is stored in the raw water tank 12, and then supplied to the membrane separation device 1 through the pressurizing pump 21. The feed water W3 supplied to the membrane separation device 1 is fed into the tubular filtration membrane 3 of the membrane separation device 1. The operation of the pressurizing pump 21 is controlled by the control device 13 as described later.

  On the other hand, the permeation side space P in the casing 2 of the membrane separation apparatus 1 becomes negative pressure by the operation of the suction pump 22. The suction pump 22 sucks in the direction substantially orthogonal to the flow of the supply water W3 flowing through the tubular filtration membrane 3 through the permeate discharge port 9. The operation of the suction pump 22 is controlled by the control device 13 as described later. The permeated water PW permeated from the tubular filtration membrane 3 is stored in the storage tank 20 through the permeated water discharge port 9 and the permeated water line 18.

  The concentrated water W <b> 4 (return sludge) discharged from the membrane separation device 1 is introduced into the return line 19 except for the excess sludge. At least a part of the concentrated water W4 is returned to the biological treatment water tank 11 and processed again.

  Next, a control method (biological treatment method) of the biological treatment apparatus 100 of the present embodiment, which is a detailed control method of the pressurization pump 21, the suction pump 22, and the first flow rate adjustment valve 23, will be described. The control device 13 of the biological treatment apparatus 100 of the present embodiment performs the control of the biological treatment apparatus 100, particularly the flow rate of the permeate PW, by sequentially executing the following control I, control II, and control III.

  The membrane separation device 1 of the present embodiment has a tubular filtration membrane 3 having a single-layer structure in which hydrophilic monomers are copolymerized, and has a low flow rate (membrane surface flow velocity: 0.15 m) due to material characteristics having a hydrophilic function. / S to 0.60 m / s) and permeate water PW can be taken at a low pressure (pressure of supply water W3: 0.1 MPa or less). The control device 13 of the biological treatment apparatus 100 performs control in consideration of the progress of fouling of the tubular filtration membrane 3 while taking advantage of this characteristic.

[Control I]
As shown in FIG. 3, the control I of the biological treatment method using the biological treatment apparatus 100 of the present embodiment adjusts the flow rate of the permeate PW, so that the operation step S11, the transmembrane pressure difference determination step S12, and the back pressure It has adjustment process S13 and adjustment range determination process S14.

  The operation step S11 is a step in which operation conditions are set to control the pressurization pump 21, the suction pump 22, and the first flow rate adjustment valve 23. The operation step S11 includes a pressurization step S11a that pressurizes the supply water to the membrane separation device 1 by controlling the pressurization pump 21, and a permeate water from the permeation side space P of the membrane separation device 1 by controlling the suction pump 22. A suction step S11b for sucking PW, an opening setting step S11c for setting the opening of the first flow rate adjusting valve 23 to 20%, and a return step S11d for returning the concentrated water W4 to the biological treatment water tank 11. ing.

The operating conditions can be appropriately determined based on the specifications of the biological treatment apparatus 100 and the like.
In the pressurization step S11a, the control device 13 controls the pressurization pump 21 based on the value of the flow rate of the supply water W3 received from the first flow meter 25 so that the membrane surface flow velocity becomes 0.15 m / s.
In the suction step S11b, the control device 13 controls the suction pump 22 so that the suction pump 22 operates in a low frequency range of 6 Hz to 20 Hz. In the opening setting step S11c, the control device 13 controls the first flow rate adjusting valve 23 so that the opening becomes 20%. Moreover, the concentrated water W4 is returned to the biological treatment water tank 11 through the return line 19 by these controls (returning process S11d).

  With the above settings, the supply water W3 has a low flow rate, and the permeate PW is sucked at a low pressure. Further, by reducing the opening degree of the first flow rate adjusting valve 23, the FLUX (the outflow amount of the permeated water PW) is controlled in a range satisfying the planned value.

The transmembrane differential pressure determination step S12 is a step of determining whether or not the transmembrane differential pressure of the membrane separation device 1 is equal to or higher than a first predetermined value. In the transmembrane differential pressure determination step S12, the control device 13 determines that the transmembrane differential pressure measured by the transmembrane differential pressure measurement device 14 (the first pressure gauge 26, the second pressure gauge 28, and the third pressure gauge 44) is the first. It is determined whether or not a predetermined value is reached. That is, the control device 13 determines whether or not the transmembrane pressure difference has increased with the progress of fouling in the tubular filtration membrane 3 in order to satisfy the planned flow rate of the permeated water PW.
As a result of this determination, when it is determined that the transmembrane pressure difference is smaller than the first predetermined value (No in S12), pressurization and suction are continued. That is, when the progress of fouling is determined to be within the allowable range, the operation is continued without changing the operation conditions.

  If it is determined that the transmembrane pressure difference is equal to or greater than the predetermined value (Yes in S12), the back pressure adjustment step S13 is executed. In the back pressure adjusting step S13, the back pressure adjusting unit 13a of the control device 13 gradually opens the first flow rate adjusting valve 23 to reduce the back pressure in the permeation side space P. That is, the flow rate of the permeated water PW is secured by increasing the opening of the first flow rate adjusting valve 23.

The adjustment range determination step S14 is a step of determining whether or not the adjustment range of the first flow rate adjustment valve 23 (back pressure adjustment device) has reached the limit (100%) in order to satisfy the planned flow rate of the permeate PW. It is. In the adjustment range determination step S14, the control device 13 determines whether or not the adjustment range (movable range) of the first flow rate adjustment valve 23 that functions as a back pressure adjustment device has reached the upper limit (opening degree 100%). As a result of this determination, when it is determined that the adjustment range of the first flow rate adjusting valve 23 has not reached the limit (No in S14), control is performed to keep the first flow rate adjusting valve 23 open gradually.
On the other hand, when it is determined that the adjustment range of the first flow rate adjustment valve 23 has reached the limit (Yes in S14), the flow rate of the permeate PW cannot be further increased, and the process proceeds to Control II.

[Control II]
As shown in FIG. 4, the control II of the biological treatment method satisfies the planned flow rate of the permeate PW, so that the first setting changing step S21, the first transmembrane pressure determining step S22, the first back pressure Adjustment step S23, first adjustment range determination step S24, second setting change step S25, second transmembrane pressure difference determination step S26, second back pressure adjustment step S27, and second adjustment range determination step S28 ,have.

  The first setting change step S21 is a step of changing the setting of the operating condition when the adjustment range of the first flow rate adjusting valve 23 reaches the limit in the adjustment range determination step S14 of the control I. In the first setting change step S21, the control device 13 changes the setting of the pressurizing pump 21 so that the membrane surface flow velocity is 0.30 m / s. That is, the pressurizing force of the pressurizing pump 21 is increased. The setting of the suction pump 22 is not changed.

By increasing the pressurizing force of the pressurizing pump 21, the membrane surface flow velocity and the flow rate of the supply water W3 are increased, and the membrane surface cleaning effect is increased. Further, the flow rate of the permeated water PW increases due to the increase in the pressure of the supply water W3.
The control device 13 controls the first flow rate adjustment valve 23 so that the opening degree becomes 20% which is an initial setting value. Thereby, the outflow amount of the permeated water PW is controlled within a range that satisfies the planned value.

In the first transmembrane differential pressure determination step S22, the control device 13 determines that the transmembrane differential pressure measured by the transmembrane differential pressure measuring device 14 is equal to or higher than a second predetermined value (a transmembrane differential pressure higher than the first predetermined value). It is determined whether or not it has been reached.
As a result of this determination, when it is determined that the transmembrane pressure difference is smaller than the second predetermined value (No in S22), pressurization and suction are continued.

  If it is determined that the transmembrane pressure difference is equal to or greater than the second predetermined value (Yes in S22), the first back pressure adjustment step S23 is executed. The back pressure adjusting unit 13a of the control device 13 gradually opens the first flow rate adjusting valve 23 to reduce the back pressure in the transmission side space P.

In the first adjustment range determination step S24, the control device 13 determines whether or not the adjustment range of the first flow rate adjustment valve 23 has reached the limit (100%). As a result of this determination, if it is determined that the adjustment range of the first flow rate adjustment valve 23 has not reached the limit, control is performed to gradually open the first flow rate adjustment valve 23.
On the other hand, when it is determined that the adjustment range of the first flow rate adjusting valve 23 has reached the limit, the flow rate of the permeated water PW cannot be further increased, so the setting of the pressurizing pump 21 is changed.

The second setting changing step S25 is a step of changing the setting of the operating condition again when the adjustment range of the first flow rate adjusting valve 23 reaches the limit. In 2nd setting change process S25, the control apparatus 13 changes the setting of the pressurization pump 21 so that it may become the membrane surface flow velocity 0.60 m / s. That is, the control device 13 changes the setting so that the supply water W3 supplied by the pressurizing pump 21 has a large flow rate.
Moreover, the control apparatus 13 controls the 1st flow regulating valve 23 so that an opening degree may be 20% which is a default value. Thereby, the outflow amount of the permeated water PW is controlled within a range that satisfies the planned value.

Hereinafter, similarly to the first transmembrane differential pressure determination step S22, the first back pressure adjustment step S23, and the first adjustment range determination step S24, the second transmembrane differential pressure determination step S26, the second back pressure adjustment step S27, And 2nd adjustment range determination process S28 is performed.
If it is determined in the second adjustment range determination step S28 that the adjustment range of the first flow rate adjustment valve 23 has reached the limit, no further increase in the flow rate of the permeate PW can be expected, and the process proceeds to Control III.

  In particular, in the control II, the concentrated water W4 increases as the supply water W3 increases, so the control device 13 adjusts the second flow rate based on the flow rate of the concentrated water W4 measured by the third flow meter 43. The valve 24 is controlled. Thereby, the flow volume of the concentrated water W4 introduced into the biological treatment water tank 11 is adjusted.

[Control III]
As shown in FIG. 5, the control III of the biological treatment method adjusts the setting change step S31, the transmembrane pressure difference determination step S32, the back pressure adjustment step S33, and the adjustment to satisfy the planned flow rate of the permeate PW. It has range determination process S34 and washing | cleaning process S35.

The setting change step S31 is a step of changing the setting of the operating condition when the adjustment range of the first flow rate adjustment valve 23 reaches the limit in the second adjustment range determination step S28 of the control II.
In the setting change step S31, the control device 13 changes the setting of the suction pump 22 so that the suction pump 22 operates from 20 Hz to 40 Hz. The setting of the pressurizing pump 21 is not changed. The increase in the suction force by the suction pump 22 increases the flow rate of the permeated water PW.
The control device 13 controls the first flow rate adjustment valve 23 so that the opening degree becomes 20% which is an initial setting value. Thereby, the outflow amount of the permeated water PW is controlled within a range that satisfies the planned value.

In the transmembrane differential pressure determination step S32, the control device 13 determines that the transmembrane differential pressure measured by the transmembrane differential pressure measurement device 14 is equal to or higher than a third predetermined value (transmembrane differential pressure higher than the second predetermined value). It is determined whether it has been reached.
As a result of this determination, when it is determined that the transmembrane pressure difference is smaller than the third predetermined value (No in S32), pressurization and suction are continued.

When it is determined that the transmembrane pressure difference is equal to or greater than the third predetermined value (Yes in S32), the control device 13 executes a back pressure adjustment step S33. The back pressure adjustment step S33 is a step of decreasing the back pressure of the permeation side space P and increasing the suction force of the suction pump 22 when the transmembrane pressure difference increases to a third predetermined value or more.
The back pressure adjustment step S33 includes a step S33a for adjusting the first flow rate adjustment valve and a step S33b for adjusting the suction pump.
In step S33a of adjusting the first flow rate adjustment valve, the back pressure adjustment unit 13a of the control device 13 gradually opens the first flow rate adjustment valve 23 to reduce the back pressure in the permeation side space P. In step S33b of adjusting the suction pump, the control device 13 gradually increases the suction force of the suction pump 22. That is, the control device 13 gradually increases the frequency of the suction pump 22 from 40 Hz.

The adjustment range determination step S34 is a step of determining whether the adjustment range of the first flow rate adjustment valve 23 has reached the limit while the suction pump 22 reaches the maximum frequency.
In the adjustment range determination step S34, the control device 13 determines whether or not the adjustment range of the first flow rate adjustment valve 23 and the adjustment range of the suction pump 22 have reached the limits. As a result of this determination, when it is determined that the limit of the adjustment range has not been reached, the first flow rate adjustment valve 23 is gradually opened and the suction force of the suction pump 22 is continuously increased.

On the other hand, when it is determined that the adjustment ranges of the first flow rate adjustment valve 23 and the suction pump 22 have reached the limit, the flow rate of the permeated water PW cannot be further increased, and the tubular filtration membrane 3 is washed.
In the cleaning step S35, the cleaning control unit 13c of the control device 13 controls the cleaning device 29 to clean the tubular filtration membrane 3.
After the cleaning step S35, if it is determined by the control device 13 that the transmembrane pressure has recovered, the process returns to the control I.

According to the above-described embodiment, the first flow rate adjusting valve 23 (back pressure adjustment) is achieved even when the transmembrane differential pressure increases due to fouling by reducing the back pressure of the tubular filtration membrane 3 based on the transmembrane pressure difference. The flow rate of the permeated water PW can be adjusted using the movable range of the apparatus.
Further, when the limit of the adjustment range of the first flow rate adjusting valve 23 is reached, the first flow rate adjusting valve 23 is again increased by increasing the pressurizing force and increasing the back pressure (closing the first flow rate adjusting valve 23). The flow rate of the permeated water PW can be adjusted using the movable range.
Further, since the tubular filtration membrane 3 has hydrophilicity, the flow rate of the permeated water PW is reduced even when the flow velocity of the supply water W3 supplied to the concentration side space S is low and the pressure of the supply water W3 is low. It becomes possible.

  Moreover, it becomes possible to adjust the sludge density | concentration (concentration magnification) of the concentrated water W4 returned to the biological treatment water tank 11 by controlling using the pressurization pump 21 and the suction pump 22 together. When increasing the sludge concentration, increase the suction force and decrease the applied pressure. When reducing the sludge concentration, reduce the suction force and increase the pressure.

Further, in the control II, by increasing the pressurizing force of the pressurizing pump 21 and controlling it to the upper limit, the pressurizing force of the pressurizing pump 21 is increased to increase the membrane surface flow rate, thereby cleaning the tubular filtration membrane 3. Can be generated.
Further, in the control III, after the suction force of the suction pump 22 is increased and controlled to the upper limit, the pressure and suction force can be reduced again by cleaning the tubular filtration membrane 3. In addition, the number of cleanings can be reduced by performing cleaning after controlling both the pressing force and the suction force to the upper limit.

  Moreover, since the biological treatment apparatus 100 of this embodiment can make a membrane surface flow velocity low, it can reduce a circulating flow rate. Thereby, the power of the pressurizing pump 21 can be reduced. Further, the diameter of the pipe can be reduced by reducing the flow rate of the circulating water.

  Moreover, it can suppress that the tubular filtration membrane 3 is obstruct | occluded by a coarse fiber part by selecting the internal diameter of the tubular filtration membrane 3 according to the amount of coarse fibers of the supply water W3.

  In addition, by forming the upper and lower portions of the casing 2 in a tapered shape, it is possible to prevent the coarse fiber material from being deposited in the header spaces S1 and S2 and the coarse fiber material from becoming granular. That is, when the casing 2 has a cylindrical shape, the corners of the end portions become dead spaces, but the upper and lower portions of the casing 2 are tapered to eliminate dead spaces and suppress the retention of coarse fibers and the like. can do.

  Further, when the biological treatment water tank 11 is located at a position lower than the membrane separation device 1, when the pressurizing pump 21 is stopped, the entire amount of the liquid inside the membrane separation device 1 including the permeated water PW is drawn due to the siphon effect. When the permeated water PW is pulled out, the suction pump 22 continues to operate wastefully until the permeated water PW is filled again, which causes a failure. By providing the siphon breaker 40 in the return line 19, the biological treatment apparatus 100 of the present embodiment can prevent the liquid from being drawn due to the siphon effect when the apparatus is stopped.

  In the above embodiment, the siphon breaker 40 is provided in the return line 19, but the present invention is not limited to this. For example, a pressure release tank may be provided in the return line 19.

Moreover, in the said embodiment, after increasing the pressurizing force of the pressurizing pump 21 in the control II, the control for increasing the suction force of the suction pump 22 was performed in the control III, but the order is not limited to this. Absent. For example, after the control I, a control for increasing the suction force of the suction pump 22 of the control III may be performed, and the control II may be performed after the control III.
Further, the control for increasing the pressurizing force of the pressurizing pump 21 and the control for increasing the suction force of the suction pump 22 may be performed alternately or simultaneously.
That is, in the control I, after the adjusting device of the first flow rate adjusting valve 23 reaches the limit, at least one of the pressurizing pump and the suction pump may be controlled.

  Further, in the above embodiment, the suction force of the suction pump 22 is increased to the upper limit of the adjustment range of the suction pump 22 in the back pressure adjustment step S33 of the control III, but similarly to the control of the pressure pump 21 of the control II. The suction force may be increased in two stages.

  Moreover, in the said embodiment, although the 1st flow regulating valve 23 was used as a back pressure adjustment apparatus which adjusts the back pressure of the permeation | transmission side space P, it is not restricted to this. For example, the downstream pressure of the permeate side space P may be changed by extending the line on the downstream side of the membrane separation apparatus 1 and providing a plurality of open valves to change the water pressure of the permeate PW.

  Moreover, in the said embodiment, although the membrane separation apparatus 1 which arranged the tubular filtration membrane 3 in parallel was employ | adopted as the membrane separation apparatus 1, it is not restricted to this. For example, as shown in FIG. 6, a plurality of tubular filtration membranes 3 may be connected in series. That is, a plurality of U-shaped first connection members that connect one end of the plurality of tubular filtration membranes 3 and the other end of the tubular filtration membrane 3 so that the plurality of tubular filtration membranes 3 are connected in series. 46 may be adopted.

  At this time, the plurality of tubular filtration membranes 3 connected in series and the effluent water inlet are directly connected by the tubular second connection member 59, and the plurality of tubular filtration membranes 3 connected in series and the concentrated water are connected. The discharge port 8 may be directly connected by the tubular third connection member 60. In this case, the first header space S1 and the second header space S2 may be omitted. Moreover, you may change the structure of the casing 2, such as eliminating the 1st cone part 5 and the 2nd cone part 6. FIG.

  Moreover, although the membrane separation apparatus 1 of the said embodiment is the structure which the supply water W3 introduce | transduced into the tubular filtration membrane 3 from the downward direction flows through the inside of the tubular filtration membrane 3, it is not restricted to this. It is good also as a structure which provides the concentrated water discharge port 8 in the lower part of the casing 2, and the supply water W3 flows the inside of the tubular filtration membrane 3 toward the downward direction.

It should be noted that a program for realizing all or part of the functions of the control unit device is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed to execute each unit. You may perform the process of. Here, the “computer system” includes an OS and hardware such as peripheral devices.
Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.

[Second Embodiment]
Hereinafter, a biological treatment apparatus according to a second embodiment of the present invention will be described with reference to the drawings. In the present embodiment, differences from the first embodiment described above will be mainly described, and description of similar parts will be omitted. The difference between the present embodiment and the first embodiment is that the biological treatment apparatus 100 of the first embodiment employs a membrane separation device unit 50 shown in FIG.
As shown in FIG. 7, in the membrane separation device unit 50 of the present embodiment, the plurality of membrane separation devices 1 </ b> B are disposed sideways in the housing 51 of the membrane separation device unit 50. That is, unlike the first embodiment, the axis A (see FIG. 8) of the cylindrical casing 2 of the membrane separation device 1 extends in the horizontal direction.

  As shown in FIG. 8, the membrane separation device 1 </ b> B includes a cylindrical casing 2, a plurality of tubular filtration membranes 3, and a reinforcing member 34 that reinforces the tubular filtration membrane 3.

  The membrane separation device 1B of this embodiment includes a reinforcing member 34 that reinforces each tubular filtration membrane 3. The reinforcing member 34 is a cylindrical member that covers each tubular filtration membrane 3 from the outer peripheral side. The tubular filtration membrane 3 is inserted through the inner peripheral side of the reinforcing member 34.

As shown in FIG. 9, the reinforcing member 34 includes a cylindrical main body 35 disposed on the outer peripheral side of the tubular filtration membrane 3, and a plurality of support portions 36 provided on the inner peripheral surface 35 a of the cylindrical main body 35. And a plurality of through holes 37 formed in the cylindrical main body 35.
The cylindrical main body 35 has a cylindrical shape. As shown in FIG. 10, the inner diameter of the cylindrical main body 35 (the diameter of the inner peripheral surface 35 a) is larger than the outer diameter of the tubular filtration membrane 3. A gap G is formed between the inner peripheral surface 35 a of the cylindrical main body 35 and the outer peripheral surface of the tubular filtration membrane 3. If the outer diameter of the tubular filtration membrane 3 is 5 mm, for example, the inner diameter of the cylindrical main body 35 can be 7 mm, for example. In this case, the gap G between the inner peripheral surface 35a of the tubular main body 35 and the outer peripheral surface of the tubular filtration membrane 3 is 2 mm. The cylindrical main body 35 is formed such that the gap G between the tubular main body 35 and the tubular filtration membrane 3 is constant.

The length of the cylindrical main body portion 35 is the same as the distance between the first partition wall 30 and the second partition wall 31. That is, the length of the cylindrical main body 35 is the same as the length of the tubular filtration membrane 3 exposed in the permeation side space P.
The cylindrical main body 35 can be formed of, for example, a lightweight metal such as titanium or aluminum, or a plastic such as polyacetal resin. The plate thickness of the cylindrical main body 35 is preferably as thin as possible within a range that does not impair the strength of the reinforcing member 34.

  The support portion 36 is a protrusion that extends in the axial direction Da (extending direction) of the cylindrical main body portion 35. A plurality of support portions 36 (eight in the present embodiment) are formed in the circumferential direction of the cylindrical main body portion 35 at intervals. The height of each support portion 36 is substantially the same as the width of the gap G between the inner peripheral surface 35 a of the cylindrical main body portion 35 and the outer peripheral surface of the tubular filtration membrane 3.

In addition, although the reinforcement member 34 of this embodiment has the eight support parts 36, if it can support the tubular filtration membrane 3, it will not restrict to this. In order to secure a wider space between the tubular main body 35 and the tubular filtration membrane 3, that is, a space where the permeated water PW is discharged, the number of support portions 36 should be as small as three. Is preferred.
Moreover, in the said embodiment, although the support part 36 is continuously formed in the axial direction Da of the cylindrical main body part 35, it is not restricted to this. The support part 36 should just be able to support the tubular filtration membrane 3, ensuring this space as much as possible, without filling the space between the cylindrical main-body part 35 and the tubular filtration membrane 3. FIG. For example, the support part 36 may be intermittently formed in the axial direction Da. Alternatively, the tubular filtration membrane 3 may be point-supported by a plurality of support protrusions that are separated from each other.

  The through-hole 37 is an opening that allows communication between the outer peripheral side of the cylindrical main body 35 and the inner peripheral side of the cylindrical main body 35. The plurality of through holes 37 are regularly (equally) arranged on the entire outer surface of the cylindrical main body 35. It is preferable to form as many through holes 37 as possible as long as the strength of the reinforcing member 34 is not impaired. The position of the through hole 37 in the circumferential direction of the cylindrical main body portion 35 is preferably different from that of the support portion 36.

  According to the above-described embodiment, even when a plurality of membrane separation devices 1B are arranged by placing the membrane separation device 1B horizontally, that is, by arranging the casing 2 so as to extend in the horizontal direction, Replacement can be facilitated. Thereby, the maintenance of the membrane separator unit 50 including the plurality of membrane separators 1B can be facilitated.

In addition, the plurality of tubular filtration membranes 3 are reinforced by the reinforcing member 34, thereby preventing the tubular filtration membrane 3 from being bent even when the tubular filtration membrane 3 is arranged to extend in the horizontal direction. Can do.
Further, the permeated water PW permeated from the tubular filtration membrane 3 is formed by forming a gap G between the inner circumferential surface 35 a of the reinforcement member 34 and the outer circumferential surface of the tubular filtration membrane 3 by the support portion 36 of the reinforcement member 34. It is possible to support the tubular filtration membrane 3 so as not to bend without impeding the flow.

  Further, when the membrane separation apparatus is installed vertically, the head difference (resistance) between the one end and the other end of the tubular filtration membrane 3 becomes large. By placing the membrane separation device 1B horizontally, the head difference is reduced and the FLUX (outflow amount) distribution can be reduced as compared with the case where the membrane separation device is placed vertically.

  Moreover, it becomes easy to connect the plurality of membrane separation devices 1B in series by placing the membrane separation device 1B horizontally. Even when the arrangement methods of the plurality of membrane separation devices 1B constituting the membrane separation device unit 50 are arranged in series, it is easy to cope with them.

  In the above embodiment, the length of the reinforcing member 34 is the same as the distance between the first partition wall 30 and the second partition wall 31, but is not limited thereto. For example, the length of the reinforcing member 34 is made longer than the distance between the first partition wall 30 and the second partition wall 31, and the reinforcing member 34 is inserted into the insertion holes 32 of the first partition wall 30 and the second partition wall 31. Also good. By setting it as such a form, the burden concerning the tubular filtration membrane 3 can be reduced more.

  In addition, the reinforcing member 34 may have a cylindrical shape and may be a mesh-like network structure disposed on the outer peripheral side of the tubular filtration membrane 3 so as to be in contact with the tubular filtration membrane 3. The net-like structure can be, for example, a plastic tube formed by combining a plurality of linear plastics in a lattice shape.

As an alternative to the linear plastic, for example, a wire formed of a metal such as stainless steel can be employed. Moreover, you may employ | adopt the wire coat | covered with vinyl etc.
Further, the method of combining a plurality of linear plastics is not limited to a lattice shape, and a plurality of linear plastics may be knitted into a hexagon.

[Third embodiment]
Hereinafter, the reinforcement member used for the membrane separation apparatus of 3rd embodiment of this invention is demonstrated based on drawing. In the present embodiment, differences from the second embodiment described above will be mainly described, and description of similar parts will be omitted. The difference between this embodiment and the second embodiment is that not only the membrane separation device unit 50 shown in FIG. 7 is adopted in the biological treatment apparatus 100 of the first embodiment, but also the reinforcing member of the membrane separation device unit 50. In place of 34, the reinforcing member 34C of FIG.
As shown in FIG. 11, the reinforcing member 34 </ b> C of the present embodiment includes a plate-like main body portion 48 having a circular plate shape, and a plurality of film insertion holes 49 formed in the plate-like main body portion 48. . The tubular filtration membrane 3 is inserted through the plurality of membrane insertion holes 49. Three reinforcing members 34 </ b> C are provided at intervals in the axial direction Da of the casing 2.

  The outer peripheral surface 48 a of the plate-like main body 48 of the reinforcing member 34 </ b> C is in contact with the inner peripheral surface of the casing 2. The reinforcing member 34 </ b> C is supported by the lower part of the reinforcing member 34 </ b> C coming into contact with the inner peripheral surface of the casing 2. The outer peripheral surface 48a at the lower portion of the reinforcing member 34C functions as a reinforcing member support portion that supports the reinforcing member 34C. Moreover, it is desirable that the notch 55 exists in a part of the reinforcing member 34C, for example, so that the permeated water PW flows in the permeate side space P.

According to the embodiment, the plurality of tubular filtration membranes 3 are mechanically connected by the reinforcing member 34C. Thereby, even when the tubular filtration membrane 3 is arranged to extend in the horizontal direction, the tubular filtration membrane 3 can be prevented from being bent.
Moreover, since the reinforcing member 34C of this embodiment supports the tubular filtration membrane 3 only at three points in the extending direction, the permeated water PW can be further permeated.

In the reinforcing member 34C of the above embodiment, the outer peripheral surface 48a of the reinforcing member 34C is in contact with the inner peripheral surface of the casing 2, but the present invention is not limited to this. That is, if the reinforcing member 34 </ b> C is supported by the inner peripheral surface of the casing 2, the upper portion of the reinforcing member 34 </ b> C does not have to abut on the inner peripheral surface of the casing 2. Moreover, the shape which a part of outer periphery contact | abuts on the casing 2 may be sufficient, for example, polygonal shape.
Further, the number of the reinforcing members 34C is not limited to three, and may be appropriately increased or decreased according to the strength of the tubular filtration membrane 3.

The embodiment of the present invention has been described in detail above, but various modifications can be made without departing from the technical idea of the present invention.
For example, regarding the number of the tubular filtration membranes 3, five tubular filtration membranes 3 are shown in FIG. 2 and the like, but the number of the tubular filtration membranes 3 is not limited to this.
In the control II and control III, the control device 13 resets the opening of the first flow rate adjusting valve 23 to the initial value 20%. However, the control device 13 is not limited to the initial value, and changes from the limit value within the adjustment range such as 30%. You may reset it to the value you set.
Moreover, you may apply the structure shown by the modification of 1st embodiment to 2nd embodiment and 3rd embodiment.

DESCRIPTION OF SYMBOLS 1 Membrane separator 2 Casing 3 Tubular filtration membrane 4 Casing body 5 First cone 6 Second cone 7 Feed water inlet 8 Concentrated water outlet 9 Permeated water outlet 11 Biological treatment water tank 12 Raw water tank 13 Controller 13a Back Pressure adjusting unit 13b Setting changing unit 13c Cleaning control unit 14 Transmembrane pressure difference measuring device 15 First line 16 Second line 17 Supply line 18 Permeate line 19 Return line 20 Storage tank 21 Pressure pump 22 Suction pump 23 First flow rate Adjusting valve (back pressure adjusting device)
24 2nd flow regulating valve 25 1st flow meter 26 1st pressure gauge 27 2nd flow meter 28 2nd pressure gauge 29 Cleaning device 30 1st partition 31 Second partition 32 Insertion hole 34 Reinforcement member 35 Cylindrical main-body part 36 Support Part 37 Through-hole 40 Siphon breaker 43 Third flow meter 44 Third pressure gauge 45 Branch line 46 First connection member 48 Plate-like main body part 49 Membrane insertion hole 50 Membrane separation device unit 51 Housing 55 Notch 59 Second connection member 60 Third connection member 100 Biological treatment device P Permeation side space PW Permeation water S Concentration side space S1 First header space S2 Second header space S3 Filtration membrane space W1 Water to be treated W2, W3 Supply water W4 Concentrated water

Claims (6)

A biological treatment water tank for treating organic substances contained in the water to be treated;
The casing is partitioned into a concentrated side space in which the feed water flowing out from the biological treatment water tank is supplied and a permeate side space in which the permeated water separated from the feed water is stored, and the hydrophilic monomer is shared. A tubular filtration membrane having a polymerized single-layer structure, and a membrane separation device having
A pressure pump for supplying the supply water to the concentration side space;
A suction pump for sucking the permeate from the permeate side space;
A back pressure adjusting device for adjusting the back pressure of the transmission side space;
A return line for returning the concentrated water discharged from the membrane separation device to the biological treatment water tank;
A transmembrane pressure difference measuring device for measuring a transmembrane pressure difference between the concentration side space and the permeation side space;
A control device for controlling the pressure pump, the suction pump, and the back pressure adjusting device based on the transmembrane pressure difference,
The controller is
When the transmembrane pressure difference increases to a predetermined value or more, a back pressure adjusting unit that controls the back pressure adjusting device to reduce the back pressure;
When the adjustment range limit of the back pressure adjusting device is reached, at least one of the pressurizing pump and the suction pump is controlled to control at least one of the pressurizing pump and the suction force of the suction pump. And a setting change unit that increases the back pressure by controlling the back pressure adjusting device.   2. The biological treatment apparatus according to claim 1, wherein the setting change unit performs control to increase the suction force of the suction pump after increasing the pressurizing force of the pressurizing pump to control the upper limit.   The biological treatment apparatus according to claim 2, wherein the control device includes a cleaning control unit that cleans the tubular filtration membrane after increasing the suction force of the suction pump to control the upper limit.   The return line is a branch line that supplies the concentrated water between the biological treatment water tank and the membrane separation device, and a flow rate of the concentrated water that is provided downstream of the branch line and flows through the return line. The biological treatment apparatus according to any one of claims 1 to 3, further comprising a second flow rate adjustment valve that performs the operation. A pressurizing step of pressurizing and supplying the feed water flowing out from the biological treatment water tank to the concentrated side space which is one side of the tubular filtration membrane having a single layer structure in which hydrophilic monomers are copolymerized;
A suction step of sucking permeate from the permeate side space which is the other side of the tubular filtration membrane;
A returning step of returning the concentrated water discharged from the concentration side space to the biological treatment water tank;
When the transmembrane pressure difference between the concentration side space and the permeation side space increases to a predetermined value or more, a back pressure adjustment step for reducing the back pressure of the permeation side space;
A biological treatment having a setting change step for increasing at least one of the pressure of the supply water and the suction force of the permeated water and increasing the back pressure when reaching the limit of the adjustment range of the back pressure Method. A biological treatment water tank for treating organic substances contained in the water to be treated;
The casing is partitioned into a concentrated side space in which the feed water flowing out from the biological treatment water tank is supplied and a permeate side space in which the permeated water separated from the feed water is stored, and the hydrophilic monomer is shared. A tubular filtration membrane having a polymerized single-layer structure, and a membrane separation device having
A pressure pump for supplying the supply water to the concentration side space;
A suction pump for sucking the permeate from the permeate side space;
A back pressure adjusting device for adjusting the back pressure of the transmission side space;
A return line for returning the concentrated water discharged from the membrane separation device to the biological treatment water tank;
A transmembrane differential pressure measurement device that measures the transmembrane differential pressure between the concentration side space and the permeation side space, to a computer of a control device of a biological treatment apparatus,
When the transmembrane pressure difference is increased to a predetermined value or more, the back pressure is reduced by controlling the back pressure adjusting device,
When the adjustment range limit of the back pressure adjusting device is reached, at least one of the pressurizing pump and the suction pump is controlled to control at least one of the pressurizing pump and the suction force of the suction pump. And increasing the back pressure by controlling the back pressure adjusting device.

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