JP6264698B2 - Biological treatment equipment - Google Patents

Description

  The present invention relates to a biological treatment apparatus having a biological treatment water tank for treating organic substances contained in treated water such as human waste.

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 the membrane separation device, a plurality of membrane modules including a cylindrical casing and a plurality of tubular filtration membranes (hollow fiber membranes) accommodated in the casing are used, and raw water is circulated inside the tubular filtration membrane. An apparatus using a filtration method is known (for example, see Patent Document 1). In a water treatment system equipped with such a membrane separation device, the permeated water that has permeated through the tubular filtration membrane is sucked by a suction pump and stored in a storage tank, for example, and used as appropriate.

  A membrane separation apparatus using a tubular filtration membrane suppresses sludge accumulation on the membrane, and in order to secure FLUX (permeate flow rate), the membrane surface flow rate (the rate at which the raw water flows inside the tubular filtration membrane) ) For example, the membrane surface flow velocity is set to 2.5 m / s.

JP 2013-052338 A

  By the way, in the said conventional water treatment system, since the flow volume of the circulating water which circulates through the water treatment system containing a membrane separator by increasing a membrane surface flow velocity increases, the tank for temporarily storing circulating water is essential. It was the composition of.

  An object of this invention is to provide the biological treatment apparatus which can aim at reduction of installation cost by making the tank for storing circulating water unnecessary.

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 effluent 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 effluent water is accommodated. A pressurizing pump that pressurizes the effluent water and supplies it to the concentrated side space, a suction pump that sucks the permeated water from the permeate side space, a pressure gauge that measures the pressure of the permeate side space, A return line for returning the concentrated water discharged from the membrane separation device to the biological treatment water tank, the pressure pump and the suction pump are controlled so that the flow rate of the permeate satisfies a planned value, and the pressure gauge of Based only on the value, have a, and a control device for controlling the supply amount of the effluent by the pressurizing pump, the control device, when the absolute value of the measured value of the pressure gauge is larger than the threshold value, The flow rate of the effluent water pressurized by the pressure pump is increased .

According to such a configuration, the membrane surface flow velocity can be lowered because the tubular filtration membrane has hydrophilicity. Thereby, the circulating flow volume of to-be-processed water can be decreased, and the tank for temporarily storing a lot of circulating water becomes unnecessary.
Further, by controlling the supply amount of the outflow water supplied to the concentration side space based on the pressure in the permeation side space, the concentrated water (return sludge) can be stably supplied to the biological treatment water tank.

  The said biological treatment apparatus WHEREIN: The said control apparatus may increase the flow volume of the said outflow water pressurized by the said pressurization pump, when the absolute value of the measured value of the said pressure gauge is larger than a threshold value.

  According to such a configuration, even when foreign matter accumulates on the inner peripheral surface of the tubular filtration membrane, the function of the tubular filtration membrane can be restored by washing away the accumulated foreign matter.

In the biological treatment apparatus, the control device may control a flow rate of the permeated water sucked by the suction pump.
According to such a configuration, the increased flow rate of the outflow water can be compensated.

  In the biological treatment apparatus, the biological treatment apparatus includes an excess sludge discharge unit that draws excess sludge from the return line, and a water level measurement device that measures the water level of the biological treatment water tank, and the control device uses the measured value of the water level measurement device. Based on this, the amount of excess sludge drawn out from the excess sludge discharge section may be controlled.

  The biological treatment apparatus includes a water level measurement device that measures a water level of the biological treatment water tank, and the control device determines a flow rate of water to be treated supplied to the biological treatment water tank based on a measurement value of the water level measurement device. You may control.

  The said biological treatment apparatus WHEREIN: The said biological treatment water tank may be a methane fermentation tank which decomposes | disassembles the organic substance contained in the said to-be-processed water with microorganisms.

  According to such a configuration, the energy of methane gas can be used for power generation or the like by efficiently recovering methane gas generated by methane fermentation.

According to the present invention, the membrane surface flow rate can be lowered because the tubular filtration membrane has hydrophilicity. Thereby, the circulating flow volume of to-be-processed water can be decreased, and the tank for temporarily storing a lot of circulating water becomes unnecessary.
Further, by controlling the supply amount of the outflow water supplied to the concentration side space based on the pressure in the permeation side space, the concentrated water (return sludge) can be stably supplied to the biological treatment water tank.

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 module of 1st embodiment of this invention. It is a flowchart explaining the control method of the biological treatment apparatus of 1st embodiment of this invention. It is a schematic sectional drawing of the membrane module of the modification of 1st embodiment of this invention. It is a schematic block diagram of the biological treatment apparatus of the modification of 1st embodiment of this invention. It is a schematic block diagram of the biological treatment apparatus 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 module 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, the biological treatment apparatus 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 apparatus 10 of the present embodiment includes a biological treatment water tank 11 for treating organic substances contained in the water to be treated W1 (organic wastewater including human waste and septic tank sludge), and the biological treatment water tank 11. A membrane separation device 13 that separates the outflow water W2 into the permeate water PW and the concentrated water W3, and a control device 12 are provided.

  The biological treatment water 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 biological treatment water tank 11 is supplied with the treated water W <b> 1 through the treated water pipe 15.

The biological treatment water tank 11 of this embodiment uses a circulation type nitrification denitrification method. The biological treatment water tank 11 has a configuration in which a denitrification tank 24, a nitrification tank 25, a secondary denitrification tank 26, and a re-aeration tank 27 are sequentially arranged in series. In addition, the biological treatment water tank 11 has a circulation line 29 for circulating a part of the water to be treated W1 discharged from the nitrification tank 25 to the denitrification tank 24 as a circulation liquid.
The biological treatment water tank 11 includes a water level measuring device 56 that measures the water level of any of the tanks that constitute the biological treatment water tank 11. The water level measuring device 56 of the present embodiment is provided in the re-aeration tank 27. Further, the water level measuring device 56 electrically transmits the measured water level value to the control device 12.

The denitrification tank 24 is an apparatus in which the inside of the tank is maintained in an anaerobic state, and in the presence of an organic carbon source, oxidized nitrogen such as nitrate nitrogen and nitrite nitrogen is reduced to nitrogen gas mainly by the action of denitrifying bacteria. is there. If necessary, an organic carbon source may be externally added.
The denitrification tank 24 includes an ORP measurement device 51 (51A) that measures an oxidation-reduction potential (ORP) of the water to be treated W1 flowing into the denitrification tank 24, and a hydrogen ion index (pH) of the water to be treated W1. PH measuring device 52 (52A) for measuring

The nitrification tank 25 is an apparatus that aerates air into the treatment liquid in the tank and oxidizes ammonia nitrogen in the treatment liquid to oxidized nitrogen mainly by the action of nitrate bacteria under aerobic conditions.
The nitrification tank 25 includes an aeration apparatus 57 (57B) that aerates air into the treatment liquid in the tank, and a DO measurement apparatus that measures the dissolved oxygen concentration (Dissolved Oxygen, DO) of the water to be treated W1 flowing into the nitrification tank 25. 53 (53B), an ORP measuring device 51 (51B), and a pH measuring device 52 (52B).

The secondary denitrification tank 26 is an apparatus in which the inside of the tank is maintained in an anaerobic state and the oxidized nitrogen remaining in the treatment liquid is reduced to nitrogen gas by the addition of an organic carbon source such as methanol.
The secondary denitrification tank 26 has an ORP measurement device 51 (51C) and a pH measurement device 52 (52C). Further, the secondary denitrification tank 26 is provided with an organic carbon source supply device 54 for injecting an organic substance such as methanol, which becomes an organic carbon source for the denitrification reaction.

The re-aeration tank 27 is an apparatus that is maintained in an aerobic condition by aeration of air and mainly oxidizes ammonia nitrogen remaining in the treatment liquid to oxidized nitrogen.
The re-aeration tank 27 includes an aeration device 57 (57D) and a DO measurement device 53 (53D) that measures a dissolved oxygen concentration.

The control device 12 performs aeration based on the dissolved oxygen concentration value measured by the DO measurement device 53, the oxidation-reduction potential value measured by the ORP measurement device 51, and the pH value measured by the pH measurement device 52. The device 57 is controlled. Specifically, the ORP measurement device 51, the pH measurement device 52, and the DO measurement device 53 transmit each measurement value as an electrical signal to the control device 12, and the control device 12 that has received these measurement values converts the measurement values into those measurement values. Based on this, the aeration air volume of the aeration device 57 is increased or decreased, and the dissolved oxygen concentration, oxidation-reduction potential, and pH values are adjusted within predetermined ranges.
In addition, it is preferable to control the oxidation-reduction potential to be 10 mV to 50 mV in order to suppress air lock (a phenomenon in which bubbles prevent the flow) in the tubular filtration membrane 3 described later and sludge dismantling.
Since the control device 12 also adjusts the pH, it is possible to prevent the nitrification / denitrification reaction from being hindered due to the low pH.

The membrane separation device 13 includes 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 arranged inside the casing 2. The membrane separation device 13 is a device that takes out the permeated water PW from the effluent water W2 using a method of filtering while circulating the effluent water W2 inside the tubular filtration membrane 3.
The tubular filtration membrane 3 partitions the casing 2 into a concentrated side space S to which the effluent water W2 is supplied and a permeate side space P in which the permeated water PW separated from the effluent water W2 is accommodated.

The biological treatment water tank 11 and the membrane separation device 13 are connected by an effluent water supply pipe 17. That is, the effluent water W <b> 2 is introduced into the membrane separation device 13 through the effluent water supply pipe 17.
The effluent water supply pipe 17 is provided with a pressurizing pump 21. The effluent water W2 flowing out from the biological treatment water tank 11 is supplied to the membrane separation device 13 while 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. The permeated water pipe 18 is connected to the storage tank 20. That is, the permeate outlet 9 (see FIG. 2) of the membrane module 1 is connected to the permeate pipe 18. The permeate pipe 18 is provided with a suction pump 22 that makes the permeate side space P negative.
The permeate pipe 18 is provided with a pressure gauge 23 for measuring the pressure (water pressure) in the permeate side space P. The pressure value measured by the pressure gauge 23 is electrically transmitted to the control device 12 and processed as described later.

The concentrated water W3 separated from the permeated water PW and discharged from the membrane separation device 13 is returned to the biological treatment water tank 11 through the return pipe 19 (return line) as the activated sludge, with the exception of excess sludge M. That is, the concentrated water discharge port 8 (see FIG. 2) of the membrane module 1 is connected to the return pipe 19.
From the return pipe 19, an excess sludge pipe 28 (surplus sludge discharge part) for branching out a part of the concentrated water W3 (activated sludge) as 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) that adjusts the flow rate of the excess sludge M.
A flow meter 66 is arranged in the return pipe 19 between the branch point and the concentrated water discharge port 8. The anemometer 66 electrically transmits the measured value of the flow rate of the concentrated water W3 to the control device 12.
The effluent water W2 flowing out from the biological treatment water tank 11 returns to the biological treatment water tank 11 via the membrane separator 13. That is, the to-be-processed water W1 circulates through the piping of the biological treatment apparatus 10.

  As described above, the plurality of membrane modules 1 are arranged in parallel. Specifically, the effluent water supply pipe 17, the permeate water pipe 18, and the return pipe 19 are connected to each membrane module 1.

As shown in FIG. 2, the membrane module 1 includes a cylindrical casing 2 and a plurality of tubular filtration membranes 3.
The casing 2 is formed above the casing body 4, the casing body 4 having a cylindrical shape, the first side wall 5 that closes the upper end of the casing body 4, the second side wall 6 that closes the lower end of the casing body 4, and the casing body 4. It has an effluent water introduction port 7, a concentrated water discharge port 8 formed below the casing body 4, and a permeate discharge port 9 formed in the casing 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 flows downward in the tubular filtration membrane 3.

The membrane module 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, in the present embodiment, in the vertical direction inside the casing 2, and have one end connected to the first partition wall 30 and the other end connected to the second partition wall 31. Yes.

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 side wall 5). A space surrounded by the casing body 4, the first partition wall 30, and the first side wall 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 side wall 6 side). A space surrounded by the casing body 4, the second partition wall 31, and the second side wall 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 water pipe 18 (see FIG. 1) through the permeate discharge port 9.

The effluent water introduction port 7 is an opening that allows communication between the outside of the casing 2 and the first header space S1. The effluent water inlet 7 is formed in the casing body 4. The effluent water introduction port 7 is provided between the first partition wall 30 and the first side wall 5 in the axis A direction of the casing 2.
The concentrated water discharge port 8 is an opening that allows communication between the outside of the casing 2 and the second header space S2. The concentrated water discharge port 8 is formed in the casing body 4. The concentrated water discharge port 8 is provided between the second partition wall 31 and the second side wall 6 in the axis A direction of the casing 2.

The permeated water discharge port 9 is an opening that allows the outside of the casing 2 to communicate with the permeate side space P. The permeated water discharge port 9 is formed in the casing body 4. The permeate discharge port 9 is provided between the first partition wall 30 and the second partition wall 31 in the axis A direction of the casing 2.
The permeate discharge port 9 is provided in the lower part of the permeate side space P. In other words, the permeated water discharge port 9 is provided slightly above the second partition wall 31. The permeate discharge port 9 is preferably provided at the lower end of the permeate side space P. The permeate discharge port 9 is formed at a position where the permeate PW that has permeated through the plurality of tubular filtration membranes 3 can be discharged as much as possible without staying in the permeate side space P.
Moreover, the permeated water pipe 18 connected to the permeated water discharge port 9 is inclined downward. That is, the permeated water pipe 18 has a shape such that the permeated water PW discharged from the permeated water discharge port 9 does not return due to gravity.

  In addition, the casing body 4 is provided with an openable / closable air vent 33 that allows communication between the outside of the casing 2 and the transmission side space P. The air vent 33 is provided in the upper part of the transmission side space P.

The concentration side space S is a space into which the effluent water W2 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 PW separated from the outflow water W2 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 is formed of a polymer filtration membrane having a single layer structure in which a hydrophilic monomer is copolymerized on a single main constituent material.
That is, the tubular filtration membrane 3 is formed of a single material as a 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 tubular filtration membrane 3.
The fact that the main material is formed of one kind of material means that the nature of the one kind of material dominates the nature of the constituent material. Specifically, it means a material in which one kind of resin has 50 mass% to 99 mass%.

  The main materials constituting the tubular filtration membrane 3 include polyolefin chlorides such as vinyl chloride resin, polysulfone (PS), polyvinylidene fluoride (PVDF), 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 effluent water W2. For example, when the coarse fiber amount α is 200 mg / liter or less with respect to the effluent water W2, 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 10 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 biologically treated water tank 11 through the to-be-treated water pipe 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 effluent water W <b> 2 that has flowed out of the biological treatment water tank 11 is supplied to the membrane separation device 13 via the pressurizing pump 21. The effluent water W <b> 2 supplied to the membrane separation device 13 is sent into the tubular filtration membrane 3 of the membrane module 1. The operation of the pressurizing pump 21 is controlled by the control device 12 as described later.

On the other hand, the permeation side space P in the casing 2 of the membrane module 1 becomes negative pressure by the operation of the suction pump 22. The suction pump 22 sucks in a direction substantially orthogonal to the flow of the effluent water W2 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 12 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 pipe 18.
The air vent 33 is closed while the suction pump 22 is operating.

Concentrated water W3 (return sludge) discharged from the membrane separation device 13 is returned to the biological treatment water tank 11 through the return pipe 19 for the entire amount excluding the excess sludge M, and is processed again.
Further, when the biological treatment apparatus 10 is stopped, the entire amount of the permeated water PW in the permeation side space P of the membrane module 1 is discharged outside the permeation side space P. In other words, the permeated water PW does not stay in the permeate-side space P even when the flow of the effluent W2 is stopped by the control device 12 stopping the pressurizing pump 21.

Next, the control method of the biological treatment apparatus 10 of this embodiment is demonstrated.
As shown in FIG. 3, according to the control method of the biological treatment apparatus 10 of the present embodiment, after the control apparatus 12 starts the operation of the biological treatment apparatus 10, The absolute value of the effluent water pressurizing step P1 for pressurizing W2, the permeated water suction step P2 for sucking the permeated water PW in the permeate side space P of the membrane separation device 13 using the suction pump 22, and the pressure in the permeate side space P The pressure determination step P3 in which the control device 12 determines whether or not the pressure is larger than the threshold value, and the effluent water that is pressurized by the pressure pump 21 when the absolute value of the pressure in the transmission side space P is larger than the threshold value. An effluent water flow rate increasing step P4 for increasing the flow rate of W2 and an effluent water flow rate adjusting step P5 for adjusting the flow rate of the effluent water W2 by the control device 12 are provided.

  In the effluent water pressurization process P1 and the permeated water suction process P2, the control device 12 satisfies the planned values of the membrane surface flow velocity and FLUX (outflow amount of the permeate water PW) based on the value of the flow velocity received from the velocimeter 66. The pressurization pump 21 and the suction pump 22 are controlled so as to be in the range. The membrane surface flow rate is a speed at which the effluent water W2 flows inside the tubular filtration membrane 3. The film surface flow velocity is, for example, 0.15 m / s-0.30 m / s.

In the pressure determination step P3, the control device 12 determines whether or not the value of the pressure (water pressure) in the transmission side space P measured by the pressure gauge 23 is larger than the threshold value.
Here, in a state where foreign matters such as sludge are accumulated on the inner peripheral surface 35 a of the tubular filtration membrane 3, the permeated water PW does not sufficiently pass through the tubular filtration membrane 3. For this reason, the absolute value of the pressure in the permeate side space P, which is set to a negative pressure by the operation of the suction pump 22, increases because the power of the suction pump 22 is increased when the permeate PW does not pass sufficiently. , Larger than the threshold.
The threshold value of the pressure in the transmission side space P can be appropriately determined by, for example, a prior experiment.

  Therefore, in order to recover this state, in the outflow water flow rate increasing step P4, the control device 12 controls the pressurizing 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 similarly to the permeated water suction step P2, and does not perform control to increase power. As the flow rate of the effluent water W2 increases (the pressure of the effluent water W2 increases), the foreign matter accumulated inside the tubular filtration membrane 3 is washed away downstream. Thereby, the function of the tubular filtration membrane 3 is restored, and the permeated water PW flows into the permeate side space P. By the 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 rate adjustment step P5, control is performed to adjust the flow rate of the effluent water W2 increased in the effluent water flow rate increase step P4.
The control device 12 controls the pressurizing pump 21 to return the flow rate of the effluent water W2 when the pressure value received from the pressure gauge 23 is equal to or less than the threshold value.

  In addition, the amount of concentrated water W3 (return sludge) is increased because the flow rate of the effluent water W2 is temporarily increased by the effluent water flow rate increasing step P4, and thus the measurement of the water level measuring device 56 received by the control device 12 is performed. The measured water level is larger than the predetermined value. Therefore, 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 pulled out from the excess sludge pipe 28, and the value of the water level measured by the water level measuring device 56. Is adjusted to a predetermined value.

  Moreover, the control apparatus 12 can control the flow volume of the to-be-processed water W1 supplied to the biological treatment water tank 11 based on the measured value of the water level measurement apparatus 56. FIG.

  According to the said embodiment, a membrane surface flow rate can be made low by forming the tubular filtration membrane 3 with the material which has hydrophilic property. The film surface flow velocity can be set to, for example, 0.15 m / s-0.30 m / s.

  When the tubular filtration membrane 3 is hydrophobic, it is necessary to increase the membrane surface flow velocity (for example, 2.5 m / s). For this reason, a circulation flow rate increases and the tank which stores circulating water temporarily, and piping which introduces circulating water into this tank are needed.

  Since the biological treatment apparatus 10 of the present embodiment can reduce the membrane surface flow velocity, the circulation flow rate can be reduced. Thereby, the power of the pressurizing pump 21 can be reduced. Moreover, the tank for temporarily storing circulating water and the piping for introducing circulating water into this tank become unnecessary. Further, the diameter of the pipe can be reduced by reducing the flow rate of the circulating water.

Further, by controlling the supply amount of the outflow water W2 supplied to the concentration side space S based on the pressure in the permeation side space P, the foreign matter is deposited even when the foreign matter is accumulated on the inner peripheral surface of the tubular filtration membrane 3. The function of the tubular filtration membrane 3 can be recovered by flushing out foreign matter. At this time, the operation of the suction pump 22 can be stabilized by performing the operation without changing the suction force of the suction pump 22. However, in the effluent water flow rate increasing step P4, the control device 12 may perform control to increase or decrease the suction force of the suction pump 22 to vibrate the tubular filtration membrane 3. This is because the foreign matter is promoted by the vibration.

When the membrane surface flow rate is low, the MLSS (floating matter) concentration difference between the inlet and outlet of the tubular filtration membrane is generally large, and sludge tends to accumulate on the outlet side. Therefore, the amount of permeated water at the outlet is reduced.
On the other hand, the membrane module 1 of the present embodiment is vertically arranged, and the effluent water W2 flowing through the tubular filtration membrane 3 flows from the top to the bottom. With such a configuration, the amount of permeated water at the outlet can be supplemented by the head difference. That is, the entire tubular filtration membrane 3 can be used effectively, and the power of the pressurizing pump 21 can be reduced.

  Moreover, it can suppress that the tubular filtration membrane 3 is obstruct | occluded with a coarse fiber part by selecting the internal diameter of the tubular filtration membrane 3 according to the amount of coarse fibers of the outflow water W2.

  In the above embodiment, the membrane module 1 in which the tubular filtration membranes 3 are arranged in parallel is adopted as the membrane module 1, but the present invention is not limited to this. For example, as shown in FIG. 4, 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 introduction port 7 are directly connected by the tubular second connection member 59, and the plurality of tubular filtration membranes 3 connected in series are concentrated. The water 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. Therefore, you may change the structure of the casing 2, such as eliminating the 1st side wall 5 and the 2nd side wall 6. FIG.

  In addition, the membrane module 1 of the above embodiment is configured such that a pressurized pump with low power can be adopted because the effluent water W2 introduced into the tubular filtration membrane 3 from above flows downward in the tubular filtration membrane 3. This is not a limitation. When a high-pressure pressurizing pump is adopted, an effluent inlet 7 is provided at the lower part of the casing 2 and a concentrated water outlet 8 is provided at the upper part of the casing 2 so that the effluent W2 moves upward in the tubular filtration membrane 3. It is good also as a structure which flows toward.

[Modification of First Embodiment]
Hereinafter, a biological treatment apparatus 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, differences from the first embodiment described above will be mainly described, and description of similar parts will be omitted.
As shown in FIG. 5, the biological treatment water tank 11B of this embodiment uses the activated sludge method.
The biological treatment water tank 11B includes an aerobic tank 62 that mixes the water to be treated W1 and the return sludge. The aerobic tank 62 includes an ORP measurement device 51 (51E), a pH measurement device 52 (52E), and a DO measurement device 53 (53E). The aerobic tank 62 includes an aeration device 57 (57E).
The treated water W1 is purified by being mixed with activated sludge and aerated.

  According to the modified example, not only the effects described in the first embodiment but also biological treatment can be performed at a lower cost.

Further, for example, there are the following modifications.
Hereinafter, a biological treatment apparatus 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, differences from the first embodiment described above will be mainly described, and description of similar parts will be omitted.
As shown in FIG. 6, the biological treatment water tank 11C of this embodiment uses methane fermentation.
The biologically treated water tank 11C includes a methane fermentation tank 63 that is a sealed container. The methane fermenter 63 is a facility for generating methane gas (biogas) by decomposing macromolecular organic matter into anaerobic bacteria (microorganisms) in the methane fermenter 63. In addition, the biological treatment water tank 11 </ b> C includes an alkaline agent supply device 68 that supplies an alkaline agent into the methane fermentation tank 63.

The methane fermentation tank 63 includes a gas circulation line 64 that circulates methane gas to the lower part of the methane fermentation tank 63. The gas circulation line 64 has a gas branch line 65 for taking out part of the methane gas flowing through the gas circulation line 64. Further, when the measured value of the pH measuring device 52 (52F) becomes excessively acidic than the predetermined value, the control device 12 supplies the alkaline agent from the alkaline agent supplying device 68, and the pH measuring device 52 (52F) Control is performed so that 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. In addition, you may send the whole quantity of methane gas to a power generation device etc., without providing the gas circulation line 64. FIG. You may provide the stirring apparatus which stirs the to-be-processed water W1 stored in the methane fermentation tank 63 in the methane fermentation tank 63. FIG.

  According to the modified example, not only the effects described in the first embodiment but also the energy of methane gas can be used for power generation or the like by collecting methane gas generated by methane fermentation. Moreover, an energy recovery rate can be improved by providing a heat recovery equipment in the generator.

[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 this embodiment and the first embodiment is that the biological treatment apparatus 10 of the first embodiment employs a membrane separation apparatus 13D shown in FIG. 7 instead of the membrane separation apparatus 13.
As shown in FIG. 7, in the membrane separation device 13D of the present embodiment, the plurality of membrane modules 1D are disposed sideways in the housing 14 of the membrane separation device 13D. That is, unlike the first embodiment, the axis A (see FIG. 8) of the cylindrical casing 2 of the membrane module 1D extends in the horizontal direction.

  As shown in FIG. 8, the membrane module 1 </ b> D 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 module 1D of the present 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 GG between the inner peripheral surface 35a of the cylindrical 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 part 36 is a protrusion that extends in the direction of the axis A (extending direction) of the cylindrical main body part 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 axis line A direction 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 axis A direction. 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 embodiment, the membrane module 1D can be easily replaced even when a plurality of membrane modules 1D are arranged by placing the membrane module 1D horizontally, that is, by arranging the casing 2 so as to extend in the horizontal direction. It can be. Thereby, the maintenance of the membrane separation apparatus 13D including the plurality of membrane modules 1D 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.

  When the membrane module 1D is placed vertically, the head difference (resistance) between one end and the other end of the tubular filtration membrane 3 is increased. When the membrane module 1D is placed horizontally, the head difference is reduced and the FLUX (outflow amount) distribution can be reduced as compared with the case where the membrane module 1D is placed vertically.

  Further, by placing the membrane module 1D horizontally, it becomes easy to connect the plurality of membrane modules 1D in series. Even when the arrangement method of the plurality of membrane modules 1D constituting the membrane separation device 13D is arranged in series, it is easy to cope with it.

  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 module 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 the present embodiment and the second embodiment is that not only the membrane separation device 13 but the membrane separation device 13D shown in FIG. 7 is adopted in the biological treatment device 10 of the first embodiment, and the membrane separation device. Instead of the 13D reinforcing member 34, the reinforcing member 34E of FIG. 11 is employed.
As shown in FIG. 11, the reinforcing member 34 </ b> E 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 34E are provided at intervals in the direction of the axis A of the casing 2.

  The outer peripheral surface 48 a of the plate-like main body 48 of the reinforcing member 34 </ b> E is in contact with the inner peripheral surface of the casing 2. The reinforcing member 34E is supported by the lower part of the reinforcing member 34E coming into contact with the inner peripheral surface of the casing 2. The lower outer peripheral surface 48a of the reinforcing member 34E functions as a reinforcing member support portion that supports the reinforcing member 34E. Further, it is desirable that the cutout 55 exists in a part of the reinforcing member 34E, 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 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, since the reinforcing member 34E of the present embodiment supports the tubular filtration membrane 3 only at three points in the extending direction, the permeated water PW can be transmitted more than the reinforcing member 34E of the fourth embodiment. it can.

In the reinforcing member 34E of the above embodiment, the outer peripheral surface 48a of the reinforcing member 34E 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> E is supported by the inner peripheral surface of the casing 2, the upper portion of the reinforcing member 34 </ b> E does not need to be in contact with 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 34E 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.
Moreover, you may apply the structure shown by the modification of 1st embodiment to 2nd embodiment and 3rd embodiment.

DESCRIPTION OF SYMBOLS 1,1D Membrane module 2 Casing 3 Tubular filtration membrane 4 Casing body 5 First side wall 6 Second side wall 7 Outflow water introduction port 8 Concentrated water discharge port 9 Permeate water discharge port 10, 10B, 10C Biological treatment device 11, 11B Biological treatment Water tank 12 Control device 13, 13D Membrane separation device 15 Water pipe to be treated 17 Outflow water supply pipe 18 Permeated water pipe 19 Return pipe (return line)
DESCRIPTION OF SYMBOLS 20 Storage tank 21 Pressure pump 22 Suction pump 23 Pressure gauge 24 Denitrification tank 25 Nitrification tank 26 Secondary denitrification tank 27 Re-aeration tank 28 Excess sludge piping (excess sludge discharge part)
DESCRIPTION OF SYMBOLS 30 1st partition 31 2nd partition 32 Insertion hole 33 Air vent 34 Reinforcement member 35 Cylindrical main-body part 36 Support part 37 Through-hole 48 Plate-like main-body part 49 Membrane penetration hole 51 ORP measurement apparatus 52 pH measurement apparatus 53 DO measurement apparatus 54 Organic carbon source supply device 55 Notch 56 Water level measurement device 57 Aeration device 62 Aerobic tank 63 Methane fermentation tank 64 Gas circulation line 65 Gas branch line 66 Current meter 67 Surplus sludge adjustment device (valve, pump)
68 Alkaline agent supply device G Gap M Excess sludge PW Permeated water S Concentrated side space S1 First header space S2 Second header space S3 Filtration membrane space P Permeated side space W1 Untreated water W2 Outflow water W3 Concentrated water

Claims (4)

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 to which effluent water flowing out from the biological treatment water tank is supplied and a permeable side space in which permeated water separated from the effluent water is accommodated, and a hydrophilic monomer is shared. A tubular filtration membrane having a polymerized single-layer structure, and a membrane separation device having
A pressurizing pump that pressurizes the effluent water and supplies it to the concentrated side space;
A suction pump for sucking the permeate from the permeate side space;
A pressure gauge for measuring the pressure in the transmission side space;
A return line for returning the concentrated water discharged from the membrane separation device to the biological treatment water tank;
The pressure pump and the suction pump are controlled so that the flow rate of the permeated water satisfies a planned value, and the supply amount of the effluent water by the pressure pump is controlled based only on the measured value of the pressure gauge. a control device for, was closed,
The said control apparatus is a biological treatment apparatus which increases the flow volume of the said outflow water pressurized by the said pressurization pump, when the absolute value of the measured value of the said pressure gauge is larger than a threshold value . Surplus sludge discharger for extracting excess sludge from the return line;
A water level measuring device for measuring the water level of the biological treatment water tank,
The biological treatment apparatus according to claim 1 , wherein the control device controls the amount of excess sludge withdrawn from the excess sludge discharge unit based on a measurement value of the water level measurement device. A water level measuring device for measuring the water level of the biological treatment tank,
The biological treatment apparatus according to claim 2 , wherein the control device controls a flow rate of water to be treated supplied to the biological treatment water tank based on a measurement value of the water level measurement device. The biological treatment apparatus according to any one of claims 1 to 3 , wherein the biological treatment water tank is a methane fermentation tank that decomposes organic matter contained in the water to be treated by microorganisms.

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