JP3592677B2 - Water treatment equipment - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a water treatment device capable of performing an appropriate purification treatment.
[0002]
[Prior art]
Conventionally, as a membrane separation means to be immersed in a reaction tank, for example, one having a structure described in JP-A-2-59098 or the like is known.
[0003]
In this conventional membrane separation means, a membrane module is immersed in sewage containing activated sludge in a reaction tank, and an air diffuser is disposed immediately below the membrane module. Are stacked side by side via a box frame for holding down the periphery of the filtration membrane, a sewage flow path between the opposed filtration membranes, and the filtration membrane and the membrane support plate. A treatment water flow path is formed between them, and projections are formed on the plate surface of each membrane support plate. These projections sandwich a filtration membrane between opposing projections, and each projection A water collection pipe is formed through the portion, and the water collection pipe is configured to communicate with the treated water flow path.
[0004]
[Problems to be solved by the invention]
However, in the above-mentioned conventional membrane separation means, a membrane support plate in which a filtration membrane is superimposed on a plate surface is sandwiched, and a narrow sewage flow path is formed between opposed filtration membranes, and contains sludge. When the sewage passes through the sewage flow path, there is a problem that sludge adheres to the sewage flow path, that is, the membrane surface, and this obstructs the membrane treatment.
[0005]
Regarding this problem, in Japanese Unexamined Patent Application Publication No. 2-59098, an air diffuser is disposed immediately below the membrane module to prevent the accumulation of sludge by an ascending flow generated by the bubbles of the aeration gas. Even if sludge accumulation on the membrane surface could be prevented, it was not an effective method for preventing or eliminating clogging of the membrane surface.
[0006]
Further, in Japanese Patent Application Laid-Open No. 4-215886, in order to solve the above problem, a pump tank communicating with an upper part of the reaction tank via an overflow weir is installed outside the reaction tank, and the pump tank is connected to the pump tank. No. 2-59098, a membrane separation means similar to that described in JP-A-2-59098 is installed, and sewage is circulated between a pump tank and a reaction tank via a pump, and sludge on the membrane surface is utilized by using a flow in the pump tank. Take measures to prevent the accumulation of
[0007]
The immersion of the membrane is characterized by eliminating the need for a circulating pump from the conventional tubular module and not installing any structure outside the reaction tank. The means described is a method of installing a new pump tank outside the reaction tank and circulating it using a pump, and immersing the membrane basically same as the configuration of the tubular type module that has been performed for a long time No new organization has been put to use.
[0008]
The present invention has been made in view of such a point, and an object of the present invention is to provide a water treatment apparatus that can prevent clogging of a membrane surface with a simple configuration and that can perform appropriate purification treatment.
[0009]
[Means for Solving the Problems]
The water treatment device according to claim 1, a reaction tank for storing wastewater to be purified, and a tubular body having an open end on both ends arranged in the reaction tank so that an axial direction thereof coincides with a vertical direction, A circulating flow generating means for generating a circulating flow passing through the cylindrical body in the reaction vessel, and arranging the membrane surface so as to be positioned along a flow direction of the drainage in the cylindrical body; Membrane filtration means for filtering , the cylindrical body is formed in a substantially cylindrical shape, the membrane separation means, so that the membrane surface is located on substantially the same plane as the inner peripheral surface of the cylindrical body It is what is arranged .
[0010]
And a cylindrical body having an open end on both ends arranged so that the axial direction coincides with the vertical direction in the reaction tank, and a circulating flow generating means for generating a circulating flow through the cylindrical body in the reaction tank, Since the membrane surface is disposed so as to be located along the flow direction of the drainage in the cylindrical body, and the membrane separation means for filtering the drainage in the cylindrical body, the membrane surface is clogged with a simple configuration. It is prevented and appropriate purification processing is performed. Further, since the membrane separation means is arranged such that the membrane surface of the membrane separation means is located on substantially the same plane as the inner peripheral surface of the substantially cylindrical tubular body, clogging of the membrane surface is more appropriately prevented. You.
[0011]
According to a second aspect of the present invention, there is provided the water treatment apparatus according to the first aspect, wherein the circulating flow generating means has rotating blades which are driven and rotated in the cylindrical body to generate a downward flow in the cylindrical body. It is.
[0012]
Then, a downward flow can be generated in the tubular body by driving rotation of the rotating blades, and a circulating flow can be appropriately generated in the reaction tank.
[0013]
According to a third aspect of the present invention, there is provided the water treatment apparatus according to the first aspect, wherein the circulating flow generating means has rotating blades which are driven and rotated in the cylindrical body to generate an upward flow in the cylindrical body. It is.
[0014]
Then, an upward flow can be generated in the cylindrical body by driving rotation of the rotating blades, and a circulating flow can be appropriately generated in the reaction tank.
[0015]
According to a fourth aspect of the present invention, in the water treatment apparatus according to any one of the first to third aspects, the gas containing oxygen is formed into a cylindrical shape such that bubbles formed by the gas come into contact with the membrane surface of the membrane separation means. It is provided with an oxygen supply means for supplying to the body.
[0016]
Since the gas bubbles from the oxygen supply unit come into contact with the membrane surface of the membrane separation unit, clogging of the membrane surface is effectively prevented.
[0017]
Water treatment apparatus 請 Motomeko 5 wherein, in the water treatment device according to any one of claims 1 to 4, in which the membrane surface of the membrane separation means are constituted by an ultrafiltration membrane.
[0018]
And, since the membrane surface of the membrane separation means is constituted by an ultrafiltration membrane, for example, activated sludge in wastewater is appropriately separated, the sludge concentration in the reaction tank is maintained at a high level, and a relatively short Advanced treatment can be performed in a short time, and a final sedimentation basin, which is required in the ordinary activated sludge method, is not required.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration of an embodiment of the water treatment apparatus of the present invention will be described with reference to the drawings.
[0020]
In FIG. 3, reference numeral 1 denotes a water treatment apparatus, which performs an anaerobic / anoxic / aerobic method on organic wastewater such as sewage and domestic wastewater, that is, wastewater to be purified. This is a sewage purification facility. The anaerobic, anoxic, and aerobic method is a treatment method that combines a biological phosphorus removal process and a biological nitrogen removal process, and utilizes the excessive intake phenomenon of activated sludge microorganisms and the nitrification denitrification reaction. Things. This method is a combination of the circulating nitrification denitrification method and the anaerobic / aerobic activated sludge method, and is generally called the A ₂ O method. That is, the phosphorus removal process applied to the present method is an anaerobic / aerobic activated sludge process, and the nitrogen removal process is a circulating nitrification denitrification process.
[0021]
The water treatment apparatus 1 includes a flow control tank for adjusting and equalizing the amount and quality of wastewater as inflow water, a screen for removing impurities in wastewater (trade name “ATAKA CF200”), and the like. A biological treatment based on the A ₂ O method is performed on the treated pretreatment means 2 and the wastewater from the pretreatment means 2, and the treated water after the purification treatment is discharged as final treated water to public water bodies. And a biological treatment facility 3. The water treatment apparatus 1 does not include a first settling tank and a final settling tank.
[0022]
The biological treatment equipment 3 has an anaerobic tank 5, an oxygen-free tank 6, and an aerobic tank 7 in this order from the upstream side which is the pretreatment means 2 side.
[0023]
Then, the wastewater from the pretreatment means 2 and the return sludge from the aerobic tank 7 are introduced into the anaerobic tank 5. The aerobic tank mixture (nitrification liquid) from the aerobic tank 7 is circulated to the anoxic tank 6. Excess sludge from the aerobic tank 7 is separately treated.
[0024]
Here, the aerobic tank 7 has a structure as shown in FIGS. 1 and 2, for example, and is a reaction for storing wastewater to be purified and activated sludge (collection of microorganisms) sent from the anoxic tank 6. A tank 11, and a substantially cylindrical tubular body 12 with open ends on both ends arranged at a substantially central position in the reaction tank 11 so that the axial direction coincides with the vertical direction in the reaction tank 11. I have.
[0025]
Further, the aerobic tank 7 includes a circulating flow generating means 14 for generating a circulating flow passing through the inside of the tubular body 12 in the reaction vessel 11 and the membrane surface 15 in the tubular body 12. It is disposed so as to be located on substantially the same plane as the inner peripheral surface of the tubular body 12 along the flow direction of the wastewater, and the wastewater (the treated water after the purification treatment) in the tubular body 12 is filtered. Immersion type membrane separation means 16 for separating the activated sludge of the present invention, and a discharge pipe 17 for discharging wastewater (permeated water which is filtered water) from which the activated sludge is separated by the membrane separation means 16 to a public water area as final treatment water. And oxygen supply means 19 such as aeration means for supplying oxygen-containing gas, for example, air, into the cylindrical body 12 such that air bubbles come into contact with the membrane surface 15 of the membrane separation means 16. ing.
[0026]
Although not shown, the other end of the drainage inflow pipe, one end of which is connected to the oxygen-free tank 6, is connected to the reaction tank 11. Note that the drainage may flow from the anoxic tank 6 into the reaction tank 11 by overflow without providing a drainage inflow pipe.
[0027]
Further, the reaction tank 11 is connected to the other end of the drainage circulation pipe having one end connected to the oxygen-free tank 6 and the other end of the return sludge pipe connected to the anaerobic tank 5 at one end. Further, a tube for excess sludge is connected to the reaction tank 11. The reaction tank 11 has a sufficient capacity to remove organic components and the like in the wastewater by the biological action of microorganisms floating in the wastewater in the reaction tank 11.
[0028]
The cylindrical body 12 has a predetermined size corresponding to the capacity of the reaction tank 11 so that the entire cylindrical body 12 is immersed in the wastewater stored in the reaction tank 11. The portion 12a is arranged at a position lower than the water surface of the waste water in the reaction tank 11, and the lower surface opening 12b of the tubular body 12 is arranged at a position higher than the bottom surface of the reaction tank 11.
[0029]
The cylindrical body 12 having a substantially cylindrical shape has an axially middle portion or a lower end portion of the cylindrical body 12 cut out, and a substantially circular annular membrane separation means 16 is fixedly provided in the cutout portion. ing. The outer side of the membrane separation means 16 provided so as to form a part of the tubular body 12 is covered with a substantially circular annular body 21 having a substantially U-shaped cross section provided integrally with the tubular body 12. ing.
[0030]
A space surrounded by an inner peripheral surface of the cylindrical body 12 and a film surface 15 which is an inner peripheral surface of the membrane separation means 16 located on substantially the same plane as the inner peripheral surface of the cylindrical body 12. Thereby, a substantially cylindrical circulation channel 22 is formed. A permeated water chamber 23 is formed by a space surrounded by the outer peripheral surface of the membrane separation means 16 and the inner surface of the annular body 21.
[0031]
One end of a discharge pipe 17 is connected to the annular body 21, and the other end of the discharge pipe 17 extends outside the reaction tank 11, and an internal flow path of the discharge pipe 17 communicates with the permeated water chamber 23. ing. In the middle or at the other end of the discharge pipe 17, suction means such as a pump is provided as necessary.
[0032]
The circulating flow generating means 14 has a driving means 31 such as a driving motor, and the driving means 31 is provided with an upper end of a vertical rotating shaft 32 which is driven and rotated by receiving a driving force from the driving means 31. ing. The rotating shaft 32 is located on substantially the same axis as the cylindrical body 12, and the lower end of the rotating shaft 32 is driven integrally with the rotating shaft 32 to rotate within the tubular body 12 to rotate the cylindrical body 12. A rotating blade 33 such as a stirring blade which is an impeller for generating a downward flow A in the body 12 is attached. The rotary blade 33 is rotatably arranged at an arbitrary position in the vertical direction of the cylindrical body 12 at a position in the cylindrical body 12.
[0033]
When a downward flow A is generated in the cylindrical body 12 by the rotation of the rotating blades 33 of the circulating flow generating means 14 in a predetermined direction, as is apparent from FIG. Is generated in the reaction tank 11, and the circulating flow over the entire reaction tank 11 circulates and flows the wastewater and the activated sludge while being stirred, so that the biological treatment is efficiently performed.
[0034]
The flow rate of the wastewater passing through the circulation channel 22 is 1.5 m / sec or more, preferably 1.5 m / sec to 3.0 m / sec, and more preferably 2.0 m / sec to 3.0 m / sec. It is set as follows. The cylindrical body 12 has an inner diameter through which the amount of water corresponding to the capacity of the reaction tank 11 passes for 2 to 5 minutes, and the rotating blades 33 having an outer diameter smaller than the inner diameter of the cylindrical body 12 It is arranged at an arbitrary position in the inside of the body 12, and has a configuration in which the inflowing wastewater and the liquid in the reaction tank can be sufficiently mixed and stirred.
[0035]
The oxygen supply means 19 has an air pressure feeding means 41 such as a blower and a compressor, and one end of a connection pipe 42 is connected to the air pressure feeding means 41. To the other end of the connection pipe 42, an air diffusion pipe 43 as an air diffusion means is attached.
[0036]
The air diffuser 43 has, for example, a substantially circular annular shape slightly smaller than the inner diameter of the cylindrical body 12, and a plurality of air diffusion holes (not shown, for example, having a diameter of about 0.5 mm A 1.5 mm pore) is formed.
[0037]
The air diffuser 43 is disposed substantially concentrically with the tubular body 12 at a position within the tubular body 12 and at an arbitrary position in the vertical direction of the tubular body 12, for example, at a position near the downstream side of the rotating blade 33. Are located.
[0038]
The membrane separation means 16 is a solid-liquid separation means for taking out the wastewater after the purification treatment from the inside of the cylindrical body 12 as the final treated water while separating the activated sludge, and as shown in FIG. It has a membrane support plate 51, which is a fixed membrane support. The membrane support 51 is formed in a substantially circular ring shape having a plurality of holes by, for example, plastic or metal, and an inner peripheral surface of the membrane support 51 has a membrane surface 15 along a vertical plane. (For example, a membrane having a particle size of about 0.001 μm to 0.1 μm) to be separated.
[0039]
The ultrafiltration membrane 52 is formed, for example, of cellulose acetate, polyacrylonitrile, polyethersulfone, or the like into a substantially cylindrical shape having an inner diameter substantially the same as the inner diameter of the cylindrical body 12. The inner peripheral surface is located on substantially the same plane as the inner peripheral surface of the tubular body 12. The membrane surface 15 constituted by the ultrafiltration membrane 52 is disposed so as to be parallel to the flow direction of the drainage in the tubular body 12.
[0040]
Next, the operation and the like of the embodiment will be described.
[0041]
The wastewater to be purified containing organic matter, nitrogen, phosphorus, etc. is pretreated by the pretreatment means 2 and then introduced into the biological treatment facility 3, where the wastewater is subjected to biological treatment by activated sludge microorganisms. It is purified and released to public water bodies as final treated water.
[0042]
In this process, in the aerobic tank 7 of the biological treatment equipment 3, the driving of the driving means 31 of the circulating flow generating means 14 drives the rotating blades 33 to rotate in a predetermined direction to generate a downward flow A. A circulating flow passing through the passage 22 is generated throughout the reaction tank 11. Further, by driving the air supply means 41 of the oxygen supply means 19, air is supplied from each hole of the air diffuser 43 to the circulation flow path 22, and the inside of the reaction tank 11 is maintained in an aerobic state. Note that the air bubbles supplied to the circulation channel 22 are miniaturized by a shearing force based on the rotation of the rotary blade 33, and the dissolving efficiency of oxygen required for biological treatment is improved.
[0043]
Then, when the wastewater to be purified and sent from the oxygen-free tank 6 is introduced into the reaction tank 11, the wastewater becomes a circulating flow together with the activated sludge and circulates and flows in the reaction tank 11 while being agitated. Is purified.
[0044]
The treated water after the purification treatment is filtered at the membrane surface 15 of the membrane separation means 16, and the activated sludge in the treated water is separated and adheres to the membrane surface 15 once.
[0045]
However, the attached activated sludge is washed away by the downward flow (sweep along the membrane surface 15) A, which is a part of the circulation flow, and is separated from the membrane surface 15.
[0046]
The attached activated sludge is also separated from the membrane surface 15 when air bubbles from the oxygen supply means 19 come into contact with the membrane surface 15. In other words, the bubbles coming out of the holes opened downward to the air diffuser 43 directly reach the membrane surface 15 and come into contact therewith with their momentum, or accompany the downward flow A from above (upstream) the membrane surface 15. Bubbles come into contact with the membrane surface 15 (bubbles slide in parallel with the membrane surface 15), or bubbles accompanied by turbulence generated by the rotation of the rotating blades 33 contact the membrane surface 15 (bubbles are The activated sludge is effectively peeled off from the membrane surface 15 by, for example, colliding with the surface 15 from any direction. Since the air bubbles do not pass through the membrane surface 15, the stirring power can be used to the maximum extent.
[0047]
Therefore, accumulation of activated sludge on the membrane surface 15 is unlikely to occur, and the membrane surface 15 is not clogged. That is, since the membrane surface 15 is directly exposed to the liquid flow and the bubble flow in the cylindrical body 12, the activated sludge is hardly deposited on the membrane surface 15, and the membrane surface 15 is not clogged.
[0048]
On the other hand, the permeated water that has passed through the membrane surface 15 of the membrane separation means 16 is discharged to the public water area through the permeated water chamber 23 and the internal flow passage of the discharge pipe 17 as final treated water.
[0049]
According to the one embodiment, the membrane surface 15 of the membrane separation means 16 in the aerobic tank 7 of the biological treatment facility 3 is not easily clogged despite the simple configuration. , Suitable and advanced purification treatment.
[0050]
Further, since the circulation channel 22 is provided in the reaction tank 11, the reaction tank 11 is made compact. Further, the activated sludge in the wastewater is appropriately separated from the wastewater by the membrane separation means 16, and the activated sludge does not flow out of the reaction tank 11, so the sludge concentration in the reaction tank 11 is maintained at a high level. Carriers and the like can be made unnecessary, and advanced treatment can be performed in a relatively short time, so that a final sedimentation basin, which is required in the ordinary activated sludge method, is not required.
[0051]
The pretreatment means 2 is preferably one capable of removing contaminants having a size of 1 mm or more, such as a screen or a first sedimentation basin. However, it is preferable to directly flow sewage such as sewage and domestic wastewater into the reaction tank 11. It does not hinder.
[0052]
Further, the circulating flow generating means 14 has rotating blades 33 which are driven and rotated in the cylindrical body 12 to generate a downward flow A in the cylindrical body 12 and generate a circulating flow in the reaction tank 11. For example, although not shown, a rotating blade that drives and rotates in the cylindrical body to generate an upward flow in the cylindrical body and generate a circulating flow in the reaction tank 11 may be used.
[0053]
Further, the membrane separation means 16 is not limited to the membrane surface 15 constituted by the ultrafiltration membrane 52. For example, although not shown, a microfiltration membrane (for example, a separation target particle diameter of about 0.1 μm to 1 μm Film).
[0054]
Further, the water treatment apparatus 1 is not limited to an apparatus using an anaerobic / anoxic / aerobic method, and can be applied to any treatment method such as an activated sludge method, a carrier method, and an anaerobic treatment method.
[0055]
Further, oxygen supply means 19 such as aeration means for supplying a gas containing oxygen to a position in the tubular body 12 such that bubbles of the gas come into contact with the membrane surface 15 emerged from the hole of the diffuser 43. It is preferable to dispose the diffuser 43 at a position near the membrane surface 15 so that the air bubbles reach the membrane surface 15 directly and contact therewith, but the arrangement is not limited to this. It may be arranged at a position on the upstream side.
[0056]
【The invention's effect】
According to the first aspect of the present invention, a tubular body having both ends opened and arranged in the reaction vessel so that the axial direction thereof coincides with the vertical direction, and a circulating flow passing through the tubular body is generated in the reaction vessel. A simple configuration because it has a circulating flow generating means to be provided, and a membrane separation means arranged so that the membrane surface is located along the flow direction of the wastewater in the cylindrical body and which filters the wastewater in the cylindrical body. Thus, clogging of the membrane surface can be prevented, and appropriate purification processing can be performed. Furthermore, since placing the membrane separation means so that the film surface of the membrane separation means is located on the inner peripheral surface and substantially the same surface of the substantially cylindrical shape of the cylindrical body, more appropriately prevent clogging of the membrane surface it can.
[0057]
According to the second aspect of the present invention, a downward flow can be generated in the tubular body by the driving rotation of the rotary blade, and a circulating flow can be appropriately generated in the reaction tank.
[0058]
According to the third aspect of the present invention, an upward flow can be generated in the tubular body by the driving rotation of the rotary blade, and a circulating flow can be appropriately generated in the reaction tank.
[0059]
According to the fourth aspect of the present invention, since bubbles caused by gas from the oxygen supply unit come into contact with the membrane surface of the membrane separation unit, clogging of the membrane surface can be effectively prevented.
[0060]
According to the invention 請 Motomeko 5, since the membrane surface of the membrane separation means are constituted by an ultrafiltration membrane, for example activated sludge in the waste water becomes to be properly separated, the sludge concentration in the reaction vessel Can be maintained at a high level, and advanced treatment can be performed in a relatively short time. For example, a final sedimentation basin required in the ordinary activated sludge method can be eliminated.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an aerobic tank in a water treatment apparatus according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a membrane separation means of an aerobic tank in the same water treatment apparatus.
FIG. 3 is a conceptual diagram showing the whole of the water treatment apparatus.
[Explanation of symbols]
1 Water treatment equipment
11 Reaction tank
12 Cylindrical body
14 Circulating flow generation means
15 Membrane surface
16 Membrane separation means
19 Oxygen supply means
33 rotating blades
52 Ultrafiltration membrane

Claims (5)

A reaction tank for storing wastewater to be purified,
A tubular body having an open end on both ends arranged so that the axial direction coincides with the vertical direction in the reaction tank;
Circulating flow generating means for generating a circulating flow through the cylindrical body in the reaction vessel;
Membrane separation means arranged so that the membrane surface is located along the flow direction of the wastewater in the cylindrical body, and filtration means for filtering the wastewater in the cylindrical body ,
The cylindrical body is formed in a substantially cylindrical shape,
The water treatment apparatus , wherein the membrane separation means is arranged such that the membrane surface is located substantially on the same plane as an inner peripheral surface of the tubular body . 2. The water treatment apparatus according to claim 1, wherein the circulating flow generating means has a rotating blade that is driven and rotated in the cylindrical body to generate a downward flow in the cylindrical body. 2. The water treatment apparatus according to claim 1, wherein the circulating flow generating means has a rotating blade that is driven and rotated in the cylindrical body to generate an upward flow in the cylindrical body. The water according to any one of claims 1 to 3, further comprising an oxygen supply means for supplying a gas containing oxygen into the cylindrical body so that bubbles of the gas come into contact with the membrane surface of the membrane separation means. Processing equipment. The water treatment apparatus according to any one of claims 1 to 4 , wherein the membrane surface of the membrane separation means is constituted by an ultrafiltration membrane.

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