TW201726238A - Biological treatment apparatus - Google Patents

Abstract

The biological treatment apparatus 10 includes: a biological treatment water tank 11 that treats organic matter contained in wastewater W1; a membrane separator apparatus 13 including a casing, and tubular filtration membranes; a pressure pump 21 that supplies an outflow water W2 to the concentrated-water space while pressurizing the outflow water W2; a suction pump 22 that suctions the permeated water from a permeated-water space; a manometer 23 that measures the pressure of the permeated-water space; a return line 19 through which concentrated water W3 is returned to the biological treatment water tank 11; and a control apparatus 12 that controls the amount of the outflow water W2, which is supplied by the pressure pump 21, based on a measured value from the manometer 23.

Description

Biological treatment device

The present invention relates to a biological treatment device having a biological treatment tank which is an organic substance contained in treated water for treating urinary urine or the like.

In the case of treating organic wastewater such as urinary urine, membrane separation using MF (microfiltration) or UF (ultrafiltration) at the time of solid-liquid separation has become mainstream.

As a membrane separation device, a membrane module is formed by a cylindrical outer casing and a plurality of tubular filtration membranes (hollow fiber membranes) housed in the outer casing, and a plurality of membrane modules are used to circulate raw water on the inner side of the tubular filtration membrane. A device for performing filtration is known (for example, refer to Patent Document 1). In the water treatment system including such a membrane separation device, the permeated water that has passed through the tubular filtration membrane is sucked by a suction pump, and is stored, for example, in a storage tank, and is suitably used.

A membrane separation device using a tubular filtration membrane, in order to suppress sludge accumulation on the membrane, and to ensure FLUX (throughflow of water), The velocity of the membrane surface (the speed at which the raw water flows through the inside of the tubular filter membrane) is accelerated. For example, the film surface flow rate is set to 2.5 m/s.

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2013-052338

In the above-described conventional water treatment system, since the flow rate of the circulating water circulating in the water treatment system including the membrane separation device is increased by increasing the flow rate of the membrane surface, it is necessary to temporarily store the circulating water. structure.

The present invention has been made to provide a biological treatment apparatus which eliminates the need for a tank for storing circulating water, thereby reducing the installation cost.

According to a first aspect of the present invention, a biological treatment apparatus includes: a biological treatment tank, a membrane separation device, a pressurizing pump, a suction pump, a pressure gauge, a return line, and a control device; the biological treatment tank is used for processing The organic substance contained in the water is treated; the membrane separation device has a casing and a tubular filtration membrane, and the tubular filtration membrane has a single-layer structure in which a hydrophilic monomer is copolymerized, and the outer casing is partitioned into: supplied a concentrated side space of the effluent water flowing out from the biological treatment tank, and a permeate side space for accommodating the permeated water separated from the effluent water; the pressurizing pump is a front The effluent water is pressurized and supplied to the concentration side space; the suction pump draws the permeated water from the permeate side space; the pressure gauge measures the pressure of the permeate side space; and the return line is the concentrated The water is returned to the biological treatment tank; the control device controls the supply amount of the effluent water by the pressure pump according to the measured value of the pressure gauge.

According to this configuration, since the tubular filtration membrane is hydrophilic, the membrane surface flow velocity can be lowered. In this way, the circulating flow rate of the water to be treated can be reduced, and a tank for temporarily storing a large amount of circulating water becomes unnecessary.

Further, the supply amount of the effluent water supplied to the concentration side space is controlled in accordance with the pressure in the permeate side space, whereby the concentrated water (sending back sludge) can be stably supplied to the biological treatment tank.

In the above biological treatment device, when the absolute value of the measured value of the pressure gauge is larger than the threshold value, the control device may increase the flow rate of the effluent water pressurized by the pressure pump.

According to this configuration, even if foreign matter accumulates on the inner peripheral surface of the tubular filtration membrane, the accumulated foreign matter can be washed away and the function of the tubular filtration membrane can be revived.

In the above biological treatment device, the control device may also control a flow rate of the permeated water sucked by the suction pump.

According to this configuration, the increased flow rate of the effluent water can be supplemented.

The biological treatment apparatus may further include: an excess sludge discharge unit that discharges excess sludge from the return line; and a water level measuring device that measures a water level of the biological treatment tank, wherein the control device is based on the The measured value of the water level measuring device is used to control the excess from the foregoing The amount of excess sludge discharged from the sludge discharge unit.

The biological treatment device may further include a water level measuring device for measuring a water level of the biological treatment water tank, wherein the control device controls the water to be treated supplied to the biological treatment water tank based on a measured value of the water level measuring device. flow.

In the biological treatment device, the biological treatment tank may be a methane fermentation tank in which the organic matter contained in the water to be treated is decomposed by microorganisms.

According to this configuration, the methane gas generated by the methane fermentation can be efficiently recovered, and the energy of the methane gas can be utilized for power generation or the like.

According to the present invention, since the tubular filtration membrane is hydrophilic, the flow velocity of the membrane surface can be lowered. In this way, the circulation flow rate of the water to be treated can be reduced, and a tank for temporarily storing a large amount of circulating water becomes unnecessary.

Further, the supply amount of the effluent water supplied to the concentration side space is controlled according to the pressure in the permeate side space, and the concentrated water (sending back sludge) can be stably supplied to the biological treatment tank.

1, 1D‧‧‧ membrane module

2‧‧‧ Shell

3‧‧‧Tubular filter membrane

4‧‧‧ Shell body

5‧‧‧First side wall

6‧‧‧Second side wall

7‧‧‧Outflow water inlet

8‧‧‧Concentrated water discharge

9‧‧‧Draining through water

10, 10B, 10C‧‧‧ biological treatment device

11, 11B‧‧‧ biological treatment tank

12‧‧‧Control device

13, 13D‧‧‧ membrane separation device

15‧‧‧Processed water piping

17‧‧‧Outflow water supply piping

18‧‧‧through water piping

19‧‧‧Returned piping (returned to pipeline)

20‧‧‧reservoir

21‧‧‧Pressure pump

22‧‧‧ suction pump

23‧‧‧ Pressure gauge

24‧‧‧Denitration tank

25‧‧‧Nitration tank

26‧‧‧Secondary denitrification tank

27‧‧‧Re-aeration tank

28‧‧‧Excess sludge piping (excess sludge discharge)

30‧‧‧First partition wall

31‧‧‧Second dividing wall

32‧‧‧ inserted through hole

33‧‧‧Exhaust port

34‧‧‧Reinforcing components

35‧‧‧Cylindrical body

36‧‧‧Support

37‧‧‧through holes

48‧‧‧ plate body

49‧‧‧film insertion hole

51‧‧‧ORP measuring device

52‧‧‧pH measuring device

53‧‧‧DO measuring device

54‧‧‧Organic carbon source supply device

55‧‧‧ gap

56‧‧‧Water level measuring device

57‧‧‧Aeration device

62‧‧‧ aerobic tank

63‧‧‧Methane fermentation tank

64‧‧‧ gas circulation pipeline

65‧‧‧ gas branch pipeline

66‧‧‧ Flowmeter

67‧‧‧Excess sludge adjustment device (valve, pump)

68‧‧‧Alkaline supply device

G‧‧‧ gap

M‧‧‧Excess sludge

PW‧‧‧through water

S‧‧‧ Concentrated side space

S1‧‧‧First head space

S2‧‧‧Second head space

S3‧‧‧Filter membrane space

P‧‧‧through side space

W1‧‧‧ treated water

W2‧‧‧ outflow water

W3‧‧‧ Concentrated water

Fig. 1 is a schematic structural view showing a biological treatment apparatus according to a first embodiment of the present invention.

Figure 2 is a schematic cross section of a membrane module according to a first embodiment of the present invention; Figure.

Fig. 3 is a flow chart for explaining a method of controlling the biological treatment apparatus according to the first embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view showing a membrane module according to a modification of the first embodiment of the present invention.

Fig. 5 is a schematic configuration diagram of a biological treatment apparatus according to a modification of the first embodiment of the present invention.

Fig. 6 is a schematic configuration diagram of a biological treatment apparatus according to a modification of the first embodiment of the present invention.

Fig. 7 is a schematic perspective view of a membrane separation apparatus according to a second embodiment of the present invention.

Fig. 8 is a schematic cross-sectional view showing a membrane module according to a second embodiment of the present invention.

Fig. 9 is a perspective view of a reinforcing member according to a second embodiment of the present invention.

Fig. 10 is a side view of the reinforcing member according to the second embodiment of the present invention as seen from the axial direction of the reinforcing member.

Figure 11 is a perspective view of a reinforcing member according to a third embodiment of the present invention.

[First Embodiment]

Hereinafter, the biological treatment device 10 according to the first embodiment of the present invention will be described in detail with reference to the drawings.

As shown in Fig. 1, the biological treatment device 10 of the present embodiment includes a biological treatment tank 11 for treating an organic substance contained in the treated water W1 (organic wastewater containing urinary urine and septic tank sludge), and is used for The effluent water W2 flowing out of the biological treatment water tank 11 is separated into a membrane separation device 13 that transmits water PW and concentrated water W3, and a control device 12.

The biological treatment tank 11 is a device that decomposes and removes BOD, nitrogen compounds, and the like in the liquid by the action of nitrifying bacteria and denitrifying bacteria. The water to be treated W1 is supplied to the biological treatment water tank 11 through the water pipe 15 to be treated.

The biological treatment water tank 11 of the present embodiment is a cyclic nitrification denitrification method. The biological treatment tank 11 is configured by sequentially arranging the denitrification tank 24, the nitrification tank 25, the secondary denitrification tank 26, and the re-aeration tank 27 in series. Further, the biological treatment water tank 11 has a circulation line 29 that circulates a part of the water to be treated W1 discharged from the nitrification tank 25 as a circulating liquid to the denitrification tank 24.

The biological treatment water tank 11 includes a water level measuring device 56 for measuring the water level of any one of the tanks constituting the biological treatment water tank 11. The water level measuring device 56 of the present embodiment is installed in the re-aeration tank 27. Further, the water level measuring device 56 electrically transmits the measured water level value toward the control device 12.

The denitrification tank 24 is maintained in an anaerobic state in the tank, and is a device that reduces the oxidized nitrogen such as nitric nitrogen and nitrous nitrate to nitrogen by the action of the denitrifying bacteria in the presence of an organic carbon source. . The organic carbon source can be added externally as necessary.

The denitrification tank 24 has an ORP measuring device 51 (51A) for measuring an oxidation-reduction potential (ORP) of the water to be treated W1 flowing into the denitrification tank 24, and a hydrogen ion concentration index for measuring the water W1 to be treated. (pH) pH measuring device 52 (52A).

The nitrification tank 25 is a device that uses air to perform aeration in the treatment liquid in the tank, and is a device that oxidizes ammonia nitrogen in the treatment liquid to oxidized nitrogen mainly by the action of the nitric acid bacteria under aerobic conditions.

The nitrification tank 25 has an aeration device 57 (57B) that uses air for aeration in the treatment liquid in the tank, and a DO measurement of dissolved oxygen concentration (Dissolved Oxygen, DO) for measuring the treated water W1 flowing into the nitrification tank 25. Device 53 (53B), ORP measuring device 51 (51B), and pH measuring device 52 (52B).

The secondary denitrification tank 26 is maintained in an anaerobic state in the tank, and is a device that reduces the oxidized nitrogen remaining in the treatment liquid to nitrogen by adding an organic carbon source such as methanol.

The secondary denitrification tank 26 has an ORP measuring device 51 (51C) and a pH measuring device 52 (52C). Further, the secondary denitrification tank 26 further includes an organic carbon source supply device 54 for injecting an organic substance which is an organic carbon source for denitrification reaction such as methanol.

The re-aeration tank 27, which maintains aerobic conditions via aeration of air, is a device that mainly oxidizes ammonia nitrogen remaining in the treatment liquid to oxidized nitrogen.

The re-aeration tank 27 includes an aeration device 57 (57D) and measurement DO measuring device 53 (53D) of dissolved oxygen concentration.

The control device 12 controls the aeration device 57 based on the dissolved oxygen concentration value measured by the DO measuring device 53, the redox potential value measured by the ORP measuring device 51, and the pH value measured by the pH measuring device 52. Specifically, the ORP measuring device 51, the pH measuring device 52, and the DO measuring device 53 transmit the respective measured values to the control device 12 as electrical signals, and the control device 12 that receives the measured values receives the measured values based on the measured values. The aeration air volume of the aeration device 57 is increased or decreased, and the dissolved oxygen concentration, the oxidation-reduction potential, and the pH value are adjusted within a predetermined range.

In order to suppress the air lock (air lock) in the tubular filtration membrane 3 to be described later and the disintegration of the sludge, it is preferable to control the oxidation-reduction potential to be 10 mV to 50 mV.

The control device 12 can also adjust the pH value, thereby preventing the nitrification and denitrification reactions from being hindered by the pH drop.

The membrane separation device 13 is provided with a plurality of membrane modules 1.

As shown in FIG. 2, the membrane module 1 has a casing 2 and a plurality of tubular filtration membranes 3 disposed inside the casing 2. The membrane separation device 13 is a device that takes out the permeated water PW from the effluent water W2 by filtering the effluent water W2 while circulating inside the tubular filtration membrane 3.

The tubular filter membrane 3 partitions the outer casing 2 into a condensed side space S to which the effluent water W2 is supplied, and a permeable side space P for accommodating the permeated water PW separated from the effluent water W2.

The biological treatment water tank 11 and the membrane separation device 13 are connected via an outflow water supply pipe 17.

In other words, the effluent water W2 is introduced into the membrane separation device 13 through the effluent water supply pipe 17.

A pressure pump 21 is provided on the outflow water supply pipe 17. The effluent water W2 flowing out of the biological treatment tank 11 is supplied to the membrane separation device 13 in a state of being pressurized by the pressurizing pump 21.

The permeated water PW separated from the membrane separation device 13 is introduced into the permeated water pipe 18. It is connected to the storage tank 20 through the water pipe 18. That is, the permeated water discharge port 9 (see FIG. 2) of the membrane module 1 is connected to the permeated water pipe 18. The permeated water pipe 18 is provided with a suction pump 22 for making the permeation side space P a negative pressure.

The permeated water pipe 18 is provided with a pressure gauge 23 that measures the pressure (water pressure) of the permeate side space P. The pressure value measured by the pressure gauge 23 is electrically transmitted to the control device 12 to perform the processing described later.

The concentrated water W3 discharged from the membrane separation device 13 by the water PW is sent back to the biological treatment tank 11 through the delivery pipe 19 (return line) as the activated sludge as the activated sludge. In other words, the concentrated water discharge port 8 (see FIG. 2) of the membrane module 1 is connected to the return pipe 19.

The excess sludge pipe 28 (excess sludge discharge part) which discharges a part of the concentrated water W3 (activated sludge) as the excess sludge M is branched. The excess sludge pipe 28 is provided with an excess sludge adjusting device 67 (for example, a pump or a valve) for adjusting the flow rate of the excess sludge M.

On the return pipe 19 between the branch and the concentrated water discharge port 8 A flow meter 66 is configured. The flow rate meter 66 electrically transmits the measured flow rate value of the concentrated water W3 toward the control device 12.

The effluent water W2 flowing out of the biological treatment water tank 11 is returned to the biological treatment water tank 11 through the membrane separation device 13. That is, the water to be treated W1 is in the piping of the biological treatment device 10.

As described above, the plurality of film modules 1 are arranged side by side. Specifically, the outflow water supply pipe 17, the permeated water pipe 18, and the return pipe 19 are connected to the respective membrane modules 1.

As shown in FIG. 2, the membrane module 1 includes a cylindrical outer casing 2 and a plurality of tubular filtration membranes 3.

The outer casing 2 has a casing main body 4 having a cylindrical shape, a first side wall 5 for closing the upper end of the outer casing main body 4, a second side wall 6 for closing the lower end of the outer casing main body 4, and being formed above the outer casing main body 4. The outflow water introduction port 7, the concentrated water discharge port 8 formed below the casing main body 4, and the permeated water discharge port 9 formed in the casing main body 4.

The membrane module 1 of the present embodiment is configured such that the effluent water W2 introduced into the tubular filtration membrane 3 from above is configured to flow downward in the tubular filtration membrane 3.

The membrane module 1 includes a first partition wall 30 and a second partition wall 31, thereby dividing the inside of the outer 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 penetrating the thickness direction of the first partition wall 30 and the second partition wall 31. 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 filter membranes 3 extend in the vertical direction in the direction of the axis A in the outer casing 2, and one end (first end) in the vertical direction in the present embodiment. The first partition wall 30 is coupled to the first partition wall 30, and the other end (second end) is coupled to the second partition wall 31.

The first partition wall 30 is a plate-shaped member that is fixed above the extending direction of the outer casing 2 (on the side of the first side wall 5). The space surrounded by the outer casing main body 4, the first partition wall 30, and the first side wall 5 is the first head space S1. The first head space S1 is a space above the first partition wall 30 in the inner space of the outer casing 2.

The second partition wall 31 is a plate-shaped member that is fixed below the extending direction of the outer casing 2 (on the side of the second side wall 6). The space surrounded by the outer casing main body 4, the second partition wall 31, and the second side wall 6 is the second head space S2. The second head space S2 is a space in the inner space of the outer casing 2 that is lower than the second partition wall 31.

The space surrounded by the outer casing main body 4, the first partition wall 30, and the second partition wall 31 and located on the outer peripheral side of the tubular filtration membrane 3 is the 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 permeated water pipe 18 through the permeated water discharge port 9 (see Fig. 1).

The outflow water introduction port 7 is an opening for communicating the outer portion of the outer casing 2 and the first head space S1. The outflow water introduction port 7 is formed in the outer casing main body 4. The outflow water introduction port 7 is provided between the first partition wall 30 and the first side wall 5 in the direction of the axis A of the outer casing 2.

The concentrated water discharge port 8 is an opening for communicating the outer portion of the outer casing 2 and the second head space S2. The concentrated water discharge port 8 is formed in the outer casing main body 4. The concentrated water discharge port 8 is disposed at a second separation in the direction of the axis A of the outer casing 2 Between the wall 31 and the second side wall 6.

The permeated water discharge port 9 is an opening for communicating the outside of the outer casing 2 and the permeation side space P. The water discharge port 9 is formed in the outer casing main body 4. The through-water discharge port 9 is disposed between the first partition wall 30 and the second partition wall 31 in the direction of the axis A of the outer casing 2.

The water discharge port 9 is provided in the lower portion of the permeation side space P. In other words, the through water discharge port 9 is provided slightly above the second partition wall 31. The permeated water discharge port 9 is preferably provided at the lower end of the permeation side space P. The permeated water discharge port 9 is formed at a position where the permeated water PW that has passed through the plurality of tubular filtration membranes 3 is not retained in the permeation side space P and is discharged as much as possible.

Further, the permeated water pipe 18 connected to the permeated water discharge port 9 is inclined downward.

In other words, the shape of the permeated water pipe 18 is such that the permeated water PW discharged from the permeated water discharge port 9 does not flow back by gravity.

Further, the casing main body 4 is provided with an exhaust port 33 for communicating with the outside of the casing 2 and the opening and closing space P. The exhaust port 33 is provided in the upper portion of the transmission side space P.

The concentration side space S is a space into which the outflow water W2 is introduced, and includes a first head space S1, a space on the inner circumference side of the tubular filter film 3, that is, a filter film inner space S3, and a second head space S2.

The permeation side space P is a space for accommodating the permeated water PW separated from the effluent water W2.

The first end of each tubular filter membrane 3 is inserted through the insertion hole 32 of the first partition wall 30 and fixed to the inner peripheral surface of the insertion hole 32. Insert hole The inner circumferential surface of 32 and the outer circumferential surface of the tubular filtration membrane 3 are sealed by a sealing material (not shown). The sealing material is preferably a material which is initially viscous and hardened over time, such as an epoxy resin or a polyurethane resin.

The second end of each tubular filter membrane 3 is fixed to the insertion hole 32 of the second partition wall 31 by the same method as the first end of the tubular filter membrane 3.

The tubular filtration membrane 3 is formed in a cylindrical shape and is a polymer filtration membrane having a single-layer structure in which a hydrophilic monomer is copolymerized in a single main constituent material.

That is, the main material of the tubular filtration membrane 3 is formed of one type of material. The main material is formed of one type of material, and one type of resin accounts for 50% by mass or more of the material (for example, resin) forming the tubular filter film 3.

In addition, the fact that the main material is formed by one type of material means that the nature of the one material governs the nature of the material. Specifically, it means a material having a resin content of 50% by mass to 99% by mass.

The main material constituting the tubular filtration membrane 3 can be a polyolefin resin such as a polyvinyl chloride resin, a polyfluorene (PS) system, a polyvinylidene fluoride (PVDF) system or a polyethylene (PE), or a polyacrylonitrile (PAN). A polymer material such as a polyether oxime system, a polyvinyl alcohol (PVA) system, or a polyimine (PI) system.

As a main material constituting the tubular filtration membrane 3, a polyvinyl chloride resin is particularly preferred. Examples of the polyvinyl chloride-based resin include a polyvinyl chloride homopolymer (polyvinyl chloride homopolymer), a copolymer of a monomer having an unsaturated bond copolymerizable with a vinyl chloride monomer, and a copolymer of a polyvinyl chloride monomer. In aggregation A graft copolymer obtained by graft-polymerizing a vinyl chloride monomer, and the vinyl chloride monomer unit is a (co)polymer composed of a chlorinated product.

Examples of the hydrophilic monomer include (1) a vinyl monomer containing a cationic group such as an amine group, an ammonium group, a pyridyl group, an imido group or a betaine structure, and/or a salt thereof, and (2) a hydroxyl group. a vinyl monomer having a hydrophilic nonionic group such as a mercaptoamine group, an ester structure or an ether structure, and (3) a vinyl monomer having an anionic group such as a carboxyl group, a sulfonic acid group or a phosphoric acid group and/or Salt, (4) other monomers, etc.

The pipe diameter of the tubular filtration membrane 3 can be appropriately selected in accordance with the properties of the effluent water W2, etc., for example, when the crude fiber content α of the effluent water W2 is 200 mg/L or less, the inner diameter of the tubular filtration membrane 3 can be set to 5 mm or less; when the crude fiber content α is more than 200 mg/L and less than 500 mg/L, the inner diameter of the tubular filtration membrane 3 may be set to 5 mm to 10 mm; when the crude fiber content α is 500 mg/L or more, The inner diameter of the tubular filtration membrane 3 is set to 10 mm or more. By selecting the pipe diameter, clogging of the tubular filtration membrane 3 caused by the coarse fibers can be suppressed.

Next, the action of the biological treatment device 10 of the present embodiment will be described.

The treated water W1 such as urine is pretreated by a pretreatment apparatus (not shown), and then sent to the biological treatment water tank 11 through the treated water pipe 15. The treated water W1 is processed in the biological treatment water tank 11. Specifically, it is an organic substance-containing microorganism contained in the treated water W1. Decompose.

Next, the effluent water W2 flowing out of the biological treatment water tank 11 is supplied to the membrane separation device 13 through the pressure pump 21. The effluent water W2 supplied to the membrane separation device 13 is sent to the tubular filtration membrane 3 of the membrane module 1. The pressurizing pump 21 controls its operation by the control device 12 as will be described later.

On the other hand, the permeation side space P in the outer casing 2 of the membrane module 1 becomes a negative pressure by the operation of the suction pump 22. The suction pump 22 is sucked in a direction substantially orthogonal to the flow of water flowing through the water discharge port 9 and flowing through the tubular filter membrane 3 through the effluent water W2. The suction pump 22 is controlled by the control device 12 as will be described later. The permeated water PW that has passed through the tubular filtration membrane 3 is stored in the storage tank 20 through the permeated water discharge port 9 and the permeated water pipe 18.

Further, in the operation of the suction pump 22, the exhaust port 33 is closed.

The concentrated water W3 (returned sludge) discharged from the membrane separation device 13 is returned to the biological treatment water tank 11 through the return pipe 19 in addition to the excess sludge M, and is processed again.

Further, when the biological treatment device 10 is stopped, the entire amount of the permeated water PW in the permeation side space P of the membrane module 1 is discharged to the outside of the permeation side space P. In other words, even when the control device 12 stops the pressurizing pump 21 and stops the flow of the water flowing out of the water W2, the permeated water PW does not remain in the permeate side space P.

Next, a method of controlling the biological treatment apparatus 10 of the present embodiment will be described.

As shown in FIG. 3, the control of the biological treatment device 10 of the present embodiment The method has the following steps: an effluent water pressurization step P1, and after the control device 12 starts the operation of the biological treatment device 10, the effluent water W2 is pressurized in the concentration side space S using the pressurizing pump 21; the permeated water suction step P2 The suction pump 22 is used to suck the permeated water PW of the permeation side space P of the membrane separation device 13; in the pressure determination step P3, the control device 12 determines whether the absolute value of the pressure in the permeate side space P is greater than the threshold value; the outflow water flow rate is increased. In step P4, when the absolute value of the pressure in the permeate side space P is larger than the threshold value, the control device 12 increases the flow rate of the outflow water W2 pressurized by the pressurizing pump 21; the outflow water flow rate adjusting step P5 flows out The flow rate of the water W2 is adjusted by the control device 12.

In the effluent water pressurizing step P1 and the permeate water sucking step P2, the control device 12 is based on the flow rate value received from the flow rate meter 66, and the film surface flow rate and the FLUX (the outflow amount of the permeated water PW) become the program value. The pressure pump 21 and the suction pump 22 are controlled in a range manner. The membrane surface flow rate refers to the flow velocity of the effluent water W2 inside the tubular filtration membrane 3. The membrane surface flow rate is, for example, 0.15 m/s to 0.30 m/s.

In the pressure determination step P3, the control device 12 determines whether or not the pressure (water pressure) value of the transmission side space P measured by the pressure gauge 23 is greater than the threshold value.

Here, in a state where foreign matter such as sludge is deposited on the inner circumferential surface 35a of the tubular filtration membrane 3, the permeated water PW cannot be sufficiently passed through the tubular filtration membrane 3. Therefore, the pressure of the transmission side space P which becomes the negative pressure by the operation of the suction pump 22 causes the absolute value of the permeated water PW to be sufficiently passed, and becomes larger than the threshold value.

The threshold value of the pressure transmitted through the side space P can be appropriately determined, for example, according to an experiment beforehand.

Then, in order to restore the state, in the outflow water flow increasing step P4, the control device 12 controls the pressure pump 21 to increase the flow rate of the outflow water W2 supplied to the concentration side space S. At this time, the control device 12 normally operates the suction pump 22 in the same manner as the permeated water suction step P2, and does not perform control for increasing the power. Since the flow rate of the effluent water W2 increases (the pressure of the effluent water W2 increases), the foreign matter accumulated on the inner side of the tubular filtration membrane 3 is washed away toward the downstream side.

In this way, the function of the tubular filtration membrane 3 is restored, and the permeated water PW flows toward the permeation side space P. Through this recovery, the pressure value transmitted from the pressure gauge 23 to the control device 12 becomes equal to or less than the threshold value.

In the effluent water flow adjustment step P5, control is performed to adjust the flow rate of the effluent water W2 added in the effluent water flow increasing step P4.

When the pressure value received from the pressure gauge 23 is equal to or less than the threshold value, the control device 12 controls the pressure pump 21 to return the flow rate of the outflow water W2 to the original state.

Further, the flow rate of the effluent water W2 is temporarily increased by the effluent water flow increasing step P4, whereby the amount of the concentrated water W3 (sent back the sludge) is increased, so that the measured water level value of the water level measuring device 56 received by the control device 12 is changed. It is bigger than the established value. Then, the control device 12 controls the excess sludge adjusting device 67 (for example, a pump or a valve) to increase the amount of excess sludge M discharged from the excess sludge pipe 28, thereby adjusting the water level measured by the water level measuring device 56. The value becomes the established value.

Further, the control device 12 can control the flow rate of the water to be treated W1 supplied to the biological treatment water tank 11 based on the measured value of the water level measuring device 56.

According to the above embodiment, the tubular filtration membrane 3 is formed of a material having hydrophilicity, whereby the flow velocity of the membrane surface can be lowered. The membrane surface flow rate can be, for example, 0.15 m/s to 0.30 m/s.

When the tubular filtration membrane 3 is hydrophobic, the membrane surface flow rate must be increased (for example, 2.5 m/s). Therefore, the circulation flow rate is increased, and it is necessary to provide a tank for temporarily storing the circulating water, and a piping for introducing the circulating water into the tank.

Since the biological treatment apparatus 10 of the present embodiment can reduce the flow velocity of the membrane surface, the circulation flow rate can be reduced. In this way, the power of the pressurizing pump 21 can be reduced.

Further, the tank for temporarily storing the circulating water and the piping for introducing the circulating water into the tank are not required. Further, by reducing the flow rate of the circulating water, it is possible to reduce the diameter of the piping.

Further, the supply amount of the effluent water W2 supplied to the condensing side space S is controlled according to the pressure in the permeable side space P, and even if foreign matter is accumulated on the inner peripheral surface of the tubular filter membrane 3, the accumulated foreign matter can be washed away. The function of the tubular filter membrane 3 is restored. Further, the operation of the suction pump 22 can be stabilized by operating the suction force of the suction pump 22 without change. However, in the effluent flow rate increasing step P4, the control device 12 can also control to increase or decrease the suction force of the suction pump 22, thereby vibrating the tubular filter membrane 3.

This vibration can promote the peeling of foreign matter.

When the flow rate of the membrane surface is low, in general, the difference in concentration of MLSS (floating matter) between the inlet and the outlet of the tubular filtration membrane is large, and sludge tends to accumulate on the outlet side. Therefore, the amount of water permeated at the outlet is reduced.

On the other hand, the membrane module 1 of the present embodiment is configured to be vertically arranged, and the effluent water W2 flowing through the tubular filtration membrane 3 flows downward from above. According to this configuration, the amount of permeate water at the outlet can be increased by using the water level difference. That is, the entire tubular filter membrane 3 can be effectively utilized, and the power of the pressurizing pump 21 can be reduced.

Further, the inner diameter of the tubular filtration membrane 3 is selected in accordance with the crude fiber content of the effluent water W2, and the tubular filtration membrane 3 can be prevented from being clogged by the coarse fibers.

Further, in the above embodiment, the membrane module 1 is a membrane module 1 in which the tubular filtration membranes 3 are arranged in parallel, but the invention is not limited thereto. For example, as shown in FIG. 4, a plurality of tubular filtration membranes 3 may be connected in series. Alternatively, the first ends of the plurality of tubular filtration membranes 3 and the second ends of the tubular filtration membrane 3 may be connected in series to each other in a plurality of tubular filtration membranes 3, and may have a plurality of U-shaped portions. The configuration of the first connecting member 46.

At this time, the plurality of tubular filtration membranes 3 and the effluent water introduction port 7 connected in series may be directly connected by the tubular second connecting member 59, and the plurality of tubular filtration membranes 3 and the concentrated water discharge port 8 connected in series may be connected. The connection is made directly by the tubular third connecting member 60. In this case, the first A head space S1 and a second head space S2 may not exist. At this time, the configuration of the outer casing 2 may be changed without providing the first side wall 5 and the second side wall 6 and the like.

Further, in the membrane module 1 of the above-described embodiment, the effluent water W2 introduced into the tubular filtration membrane 3 from above is flowing downward in the tubular filtration membrane 3, so that the pressure pump having a small power is used, but the pressure is not limited thereto. When a pressurized pump having a large power is used, an outflow water introduction port 7 may be provided in the lower portion of the outer casing 2, and a concentrated water discharge port 8 may be provided in the upper portion of the outer casing 2, and the outflow water W2 may flow upward in the tubular filtration membrane 3 .

[Modification of First Embodiment]

Hereinafter, a biological treatment device 10B according to a modification of the first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the differences from the first embodiment will be mainly described, and the description of the same portions will be omitted.

As shown in Fig. 5, the biological treatment water tank 11B of the present embodiment is an activated sludge method.

The biological treatment water tank 11B includes an aerobic tank 62 for mixing the water to be treated W1 and the returned sludge. The aerobic tank 62 includes an ORP measuring device 51 (51E), a pH measuring device 52 (52E), and a DO measuring device 53 (53E). The aerobic tank 62 is provided with an aeration device 57 (57E).

The treated water W1 is mixed with activated sludge and aerated, and is purified.

According to the above modification, in addition to the effects described in the first embodiment, biological treatment can be performed at a lower cost.

Further, for example, the following modifications are also possible.

Hereinafter, a biological treatment device 10C according to a modification of the first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the differences from the first embodiment will be mainly described, and the description of the same portions will be omitted.

As shown in Fig. 6, the biological treatment water tank 11C of the present embodiment is subjected to methane fermentation.

The biological treatment water tank 11C is provided with a methane fermentation tank 63 as a sealed container. The methane fermentation tank 63 is a device that generates a methane gas (biomass gas) by decomposing a polymer organic substance by an anaerobic bacteria (microorganism) in the methane fermentation tank 63. Further, the biological treatment water tank 11C includes an alkaline agent supply device 68 that supplies an alkali agent to the methane fermentation tank 63.

The methane fermentation tank 63 includes a gas circulation line 64 that circulates methane gas toward the lower portion of the methane fermentation tank 63. The gas circulation line 64 has a gas branch line 65 that takes out a part of the methane gas flowing through the gas circulation line 64. Further, when the measured value of the pH measuring device 52 (52F) is excessively acidic compared to the predetermined value, the control device 12 is controlled to supply the alkaline agent from the alkaline agent supply device 68 to cause the pH measuring device 52 (52F). The measured value becomes the predetermined value.

The methane gas taken out through the gas branch line 65 can be sent to a power generator or the like for use. The gas circulation line 64 may not be provided, and the entire amount of methane gas may be sent to a power generation device or the like. A stirring device for agitating the water to be treated W1 stored in the methane fermentation tank 63 may be provided in the methane fermentation tank 63.

According to the above-described modification, in addition to the effects described in the first embodiment, the methane gas generated by the methane fermentation can be recovered, and the energy of the methane gas can be utilized for power generation or the like. In addition, the energy recovery rate can be increased by providing a heat recovery device in the generator.

[Second embodiment]

Hereinafter, a biological treatment apparatus according to a second embodiment of the present invention will be described based on the drawings. In the present embodiment, the differences from the first embodiment will be mainly described, and the description of the same portions will be omitted. The present embodiment differs from the first embodiment in that the biological treatment device 10 of the first embodiment employs the membrane separation device 13D shown in Fig. 7 instead of the membrane separation device 13.

As shown in Fig. 7, in the membrane separation device 13D of the present embodiment, a plurality of membrane modules 1D are arranged in the lateral direction in the casing 14 of the membrane separation device 13D. In other words, the axis A (see FIG. 8) of the cylindrical outer casing 2 of the membrane module 1D extends in the horizontal direction unlike the first embodiment.

As shown in FIG. 8, the membrane module 1D includes a cylindrical outer casing 2, a plurality of tubular filtration membranes 3, and a reinforcing member 34 for reinforcing the tubular filtration membrane 3.

The membrane module 1D of the present embodiment includes a reinforcing member 34 for reinforcing each tubular filtration membrane 3. The reinforcing member 34 is a tubular member that covers each tubular filter membrane 3 from the outer peripheral side. The tubular filtration membrane 3 is inserted into the inner peripheral side of the reinforcing member 34.

As shown in FIG. 9, the reinforcing member 34 has a cylindrical main body portion 35 disposed on the outer peripheral side of the tubular filter membrane 3, a plurality of support portions 36 provided on the inner peripheral surface 35a of the tubular main body portion 35, and formed. A plurality of through holes 37 in the cylindrical body portion 35.

The cylindrical body portion 35 has a cylindrical shape. As shown in FIG. 10, the inner diameter (the diameter of the inner circumferential surface 35a) of the cylindrical main body portion 35 is larger than the outer diameter of the tubular filtration membrane 3. A gap G is formed between the inner circumferential surface 35a of the tubular main body portion 35 and the outer circumferential surface of the tubular filtration membrane 3. When the outer diameter of the tubular filtration membrane 3 is set to, for example, 5 mm, the inner diameter of the cylindrical main body portion 35 can be set, for example, to 7 mm. In this case, the gap G between the inner circumferential surface 35a of the cylindrical main body portion 35 and the outer circumferential surface of the tubular filtration membrane 3 was 2 mm. The cylindrical body portion 35 is formed such that the gap G between the tubular body portion 3 and the tubular filter film 3 is constant.

The length of the cylindrical body portion 35 is the same as the interval between the first partition wall 30 and the second partition wall 31. That is, the length of the tubular main body portion 35 is the same as the length of the tubular filtration membrane 3 exposed in the permeation side space P.

The cylindrical main body portion 35 can be formed, for example, of a light metal such as titanium or aluminum or a plastic such as polyacetal resin. The thickness of the cylindrical main body portion 35 is preferably as thin as possible within a range in which the strength of the reinforcing member 34 is not impaired.

The support portion 36 is a protrusion that extends in the direction of the axis A (the extending direction) of the cylindrical body portion 35. The support portion 36 is formed in plural in the circumferential direction of the cylindrical body portion 35 (eight in the present embodiment). The height of each of the support portions 36 is substantially the same as the width G of the gap between the inner circumferential surface 35a of the tubular main body portion 35 and the outer circumferential surface of the tubular filter film 3.

Although the reinforcing member 34 of the present embodiment has eight support portions 36, the tubular filter film 3 is not limited thereto as long as it can support the tubular filter membrane 3. In order to ensure a wider space between the space between the tubular main body portion 35 and the tubular filter film 3, that is, the space through which the permeated water PW is discharged, the number of the support portions 36 is preferably set to three or less, and the smaller the better.

Further, in the above-described embodiment, the support portion 36 is continuously formed in the direction of the axis A of the cylindrical body portion 35, but the invention is not limited thereto. The support portion 36 may be supported by the tubular filter membrane 3 so as not to fill the space between the tubular body portion 35 and the tubular filter membrane 3 as much as possible. For example, the support portion 36 may be intermittently formed in the direction of the axis A. Further, the tubular filter membrane 3 may be supported by a plurality of support projections separated from each other.

The through hole 37 is an opening that allows the outer peripheral side of the cylindrical main body portion 35 to communicate with the inner peripheral side of the cylindrical main body portion 35. The plurality of through holes 37 are arranged in a uniform manner (equal) on the outer surface of the cylindrical main body portion 35. The through hole 37 is formed so as not to detract from the strength of the reinforcing member 34. The position of the through hole 37 in the circumferential direction of the cylindrical main body portion 35 is preferably different from the support portion 36.

According to the above embodiment, even when the film module 1D is disposed in the horizontal direction and the outer casing 2 is extended in the horizontal direction, the film module 1D can be easily replaced even when the film module 1D is disposed in plural. Thus, the maintenance of the membrane separation device 13D composed of the plurality of membrane modules 1D can be easily performed.

In addition, a plurality of tubular filter membranes 3 utilize reinforcing members The reinforcing is performed at 34, and even when the tubular filtration membrane 3 is disposed to extend in the horizontal direction, the tubular filtration membrane 3 can be prevented from being bent.

Further, the support portion 36 of the reinforcing member 34 is used to form a gap G between the inner circumferential surface 35a of the reinforcing member 34 and the outer circumferential surface of the tubular filtration membrane 3, thereby preventing the flow of the permeated water PW transmitted through the tubular filtration membrane 3 from being impeded. The tubular filter membrane 3 is supported so as not to be bent.

Further, in the case where the film module 1D is longitudinally disposed, the water level difference (resistance) of the first end and the second end of the tubular filter film 3 becomes large. By arranging the film modules 1D in the lateral direction, the water level difference can be made smaller and the FLUX (outflow amount) distribution can be reduced as compared with the case where the film modules 1D are arranged in the longitudinal direction.

Further, by arranging the film modules 1D laterally, it is easy to connect a plurality of film modules 1D in series with each other. Even if the arrangement of the plurality of film modules 1D constituting the membrane separation device 13D is in the case of a series, it can be easily handled.

In the above embodiment, the length of the reinforcing member 34 is set to be the same as the interval 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 may be set longer than the interval between the first partition wall 30 and the second partition wall 31, and the reinforcing member 34 may be inserted into the first partition wall 30 and the second partition wall 31. Through hole 32. By adopting such a form, the burden applied to the tubular filtration membrane 3 can be further alleviated.

Further, the reinforcing member 34 may be configured in a tubular shape and arranged in contact with the tubular filtration membrane 3 on the outer peripheral side of the tubular filtration membrane 3 a network structure. The mesh structure is, for example, a plastic tube formed by combining a plurality of linear plastics into a lattice shape.

Instead of the linear plastic, for example, a wire formed of a metal such as stainless steel. In addition, a metal wire covered with a vinyl or the like can also be used.

Further, the combination of the plurality of linear plastics is not limited to the lattice shape, and a plurality of linear plastics can be knitted into a hexagonal shape.

[Third embodiment]

Hereinafter, a reinforcing member used in the membrane module of the third embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the differences from the second embodiment will be mainly described, and the description of the same portions will be omitted. The present embodiment differs from the second embodiment in that, in the biological treatment device 10 of the first embodiment, the membrane separation device 13D shown in Fig. 7 is used instead of the membrane separation device 13, and instead of the membrane separation device 13D, The reinforcing member 34E is used as the reinforcing member 34.

As shown in FIG. 11, the reinforcing member 34E of the present embodiment has a plate-like main body portion 48 having a circular plate shape, and a plurality of film insertion holes 49 formed in the plate-shaped main body portion 48. The tubular filtration membrane 3 is inserted through a plurality of membrane insertion holes 49, respectively. The reinforcing member 34E is provided in three at intervals in the direction of the axis A of the outer casing 2.

The outer peripheral surface 48a of the plate-like main body portion 48 of the reinforcing member 34E abuts against the inner peripheral surface of the outer casing 2. The reinforcing member 34E is supported such that the lower portion of the reinforcing member 34E abuts against the inner circumferential surface of the outer casing 2. Reinforcement member The lower outer peripheral surface 48a of the 34E is a reinforcing member supporting portion for supporting the reinforcing member 34E. Further, in order to allow the permeated water PW to flow through the permeate side space P, it is preferable that a notch 55 exists in a part of the reinforcing member 34E, for example.

According to the above embodiment, the plurality of tubular filtration membranes 3 are mechanically coupled by the reinforcing member 34E. 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.

Further, in the reinforcing member 34E of the present embodiment, the tubular filter film 3 is supported by only three points in the extending direction, and the permeating water PW can be more easily transmitted than the reinforcing member 34E of the second embodiment.

In the reinforcing member 34E of the above-described embodiment, the outer peripheral surface 48a of the reinforcing member 34E is brought into contact with the inner peripheral surface of the outer casing 2, but the invention is not limited thereto. In other words, the reinforcing member 34E may be supported by the inner peripheral surface of the outer casing 2, and the upper portion of the reinforcing member 34E may not abut against the inner peripheral surface of the outer casing 2. Further, for example, a shape in which a part of the outer circumference abuts against the outer casing 2 can be formed in a polygonal shape or the like.

Further, the number of the reinforcing members 34E is not limited to three, and may be appropriately increased or decreased according to the strength of the tubular filtration membrane 3.

The above is a detailed description of the embodiments of the present invention, and various modifications can be made without departing from the spirit and scope of the invention.

For example, although the number of the tubular filtration membranes 3 is shown in FIG. 2 and the like, five tubular filtration membranes 3 are shown, but the number of the tubular filtration membranes 3 is not limited thereto.

Further, the configuration shown in the modification of the first embodiment may be applied to the second embodiment or the third embodiment.

[Industry Utilization]

According to this biological treatment apparatus, since the tubular filtration membrane is hydrophilic, the flow velocity of the membrane surface can be lowered. In this way, the circulating flow rate of the water to be treated can be reduced, and a tank for temporarily storing a large amount of circulating water becomes unnecessary.

Further, the supply amount of the effluent water supplied to the concentration side space is controlled in accordance with the pressure in the permeate side space, whereby the concentrated water can be stably supplied to the biological treatment tank (returning the sludge).

1‧‧‧ membrane module

10‧‧‧ Biological treatment device

11‧‧‧ Biological treatment sink

12‧‧‧Control device

13‧‧‧ membrane separation device

15‧‧‧Processed water piping

17‧‧‧Outflow water supply piping

18‧‧‧through water piping

19‧‧‧Returned piping (returned to pipeline)

20‧‧‧reservoir

21‧‧‧Pressure pump

22‧‧‧ suction pump

23‧‧‧ Pressure gauge

24‧‧‧Denitration tank

25‧‧‧Nitration tank

26‧‧‧Secondary denitrification tank

27‧‧‧Re-aeration tank

29‧‧‧Circular pipeline

28‧‧‧Excess sludge piping (excess sludge discharge)

51, 51A, 51B, 51C‧‧‧ ORP measuring device

52, 52A, 52B, 52C‧‧‧ pH measuring device

53, 53B, 53D‧‧‧DO measuring device

54‧‧‧Organic carbon source supply device

56‧‧‧Water level measuring device

57, 57B, 57D‧‧‧ aeration device

66‧‧‧ Flowmeter

67‧‧‧Excess sludge adjustment device (valve, pump)

M‧‧‧Excess sludge

PW‧‧‧through water

W1‧‧‧ treated water

W2‧‧‧ outflow water

W3‧‧‧ Concentrated water

Claims (6)

A biological treatment device comprising: a biological treatment tank, a membrane separation device, a pressure pump, a suction pump, a pressure gauge, a return line, and a control device; the biological treatment tank is for treating organic substances contained in the water to be treated; The membrane separation device has a casing and a tubular filtration membrane having a single-layer structure in which a hydrophilic monomer is copolymerized, and the outer casing is partitioned to be supplied from the biological treatment tank. a concentrating side space of the effluent water for accommodating a permeate side space of the permeated water separated from the effluent water; the pressurizing pump pressurizing the effluent water to supply the concentration side space; the suction pump is The permeate side space absorbs the permeated water; the pressure gauge measures a pressure in the permeate side space; and the return line returns the concentrated water discharged from the membrane separation device to the biological treatment tank; the control device is The supply amount of the aforementioned effluent water by the aforementioned pressure pump is controlled based on the measured value of the aforementioned pressure gauge. The biological treatment device according to claim 1, wherein the control device causes the effluent water pressurized by the pressure pump when the absolute value of the measured value of the pressure gauge is greater than a threshold value The traffic has increased. The biological treatment device of claim 2, wherein The control device controls the flow rate of the permeated water sucked by the suction pump. The biological treatment device according to claim 2, further comprising: an excess sludge discharge unit that discharges excess sludge from the return line; and a water level measuring device that measures a water level of the biological treatment tank, The control device controls the amount of excess sludge discharged from the excess sludge discharge unit based on the measured value of the water level measuring device. The biological treatment device according to any one of claims 2 to 4, further comprising: a water level measuring device for measuring a water level of the biological treatment water tank, wherein the control device controls the supply based on a measured value of the water level measuring device The flow rate of the treated water to the aforementioned biological treatment tank. The biological treatment device according to any one of claims 1 to 5, wherein the biological treatment water tank is a methane fermentation tank in which an organic substance contained in the water to be treated is decomposed by microorganisms.