JP4187889B2 - Aerobic filter bed tank and septic tank - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an aerobic filter bed tank, a sewage purification tank, and a method for cleaning the filtration layer of the aerobic filter bed tank, and more specifically, an aerobic filter bed tank suitably used for sewage treatment such as manure and miscellaneous waste water, and The present invention relates to a sewage purification tank equipped with the aerobic filter bed tank and a method for cleaning the filtration layer of the aerobic filter bed tank.
[0002]
[Prior art]
Generally well-known sewage septic tanks are usually anaerobic treatment tanks (first chamber and second chamber) partitioned by a partition wall, an aerobic treatment tank (aerobic filter bed tank), a precipitation tank (or treated water tank) and It consists of a disinfection tank. The sewage supplied from the inflow port is sequentially transferred from the first chamber of the anaerobic treatment tank to the downstream, finally sterilized in the disinfection tank, and discharged from the outflow port to the outside.
[0003]
Several structures of the aerobic filter bed tank in the sewage septic tank are conventionally known. However, as shown in FIG. 6, the applicant previously aerobically sandwiched a porous plate (not shown). The filter bed tank is divided into an upper filter bed (biological reaction layer or R zone) 1 and a lower filter bed (filter layer or F zone) 2, and the filter bed layer is filled with a granular carrier, A structure is proposed in which aeration pipes 4a and 4b are installed in the air and a washing drainage outlet 5a which is a liquid suction port of the transfer pump (air lift pump) 5 is installed in the lower part of the aerobic filter bed tank C (Japanese Unexamined Patent Publication No. Hei 9-1993). No. 248584). At the time of washing the aerobic filter bed tank C in this sewage septic tank, after aeration from the diffuser pipes 4a and 4b under the two filter beds, the washing drainage of the lower part of the aerobic filter bed tank via a transfer pump (air lift pump) 5 The washing waste water is withdrawn from the extraction port 5a and transferred to the upper part of the anaerobic treatment tank (first chamber), and the advection water from the anaerobic treatment tank (second chamber) pushed out with the transfer is aerobic filter bed tank C is introduced into the upper filter bed.
[0004]
Then, during the washing, the lower filter bed is caused to flow uniformly by aeration, and floating suspension (also referred to as biofilm peeling sludge, hereinafter abbreviated as SS) trapped in the lower filter bed is peeled off. Then, the waste water is returned from the washing drain outlet 5a to the anaerobic treatment tank (first chamber) through the transfer pump (air lift pump) 5 as washing waste water. At this time, the amount of the cleaning waste water to be drawn is determined by the area of the bottom surface of the aerobic filter bed tank C and the speed of the cleaning waste water passing through the bottom surface.
[0005]
[Problems to be solved by the invention]
However, when the distance between the lower end of the lower filter bed 2 and the bottom surface of the lower filter bed 2 in the aerobic filter bed tank C is long, the SS far from the washing drain outlet 5a has a settling force than the force sucked into the washing drain outlet 5a. Tends to settle and settle on the bottom. Moreover, the settled SS stays in the place and becomes anaerobic, which adversely affects the performance of sewage treatment. The present invention is intended to solve such a problem, and the object of the present invention is to perform aerobic filtration even when the lower end of the lower filter bed 2 and the bottom of the filter bed are separated. To provide a cleaning method for an aerobic filter bed tank and a sewage septic tank, or a lower filter bed (filter layer) in an aerobic filter bed tank, in which SS does not stay at the bottom of the floor tank C and the performance of sewage treatment can be maintained well. It is.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the aerobic filter bed of the present invention has the following configuration. That is, the present invention firstly has two filter beds of the biological reaction layer 1 and the filter layer 2, and each of the diffuser tubes 4a under each filter bed (which means the lower part or the lower part, hereinafter the same). , an aerobic filter bed tank C with 4b, a lower diffusing tube 4b under side of the filtration layer 2, further air jet between the bottom of the aerobic filter bed tank and the filtering layer The aerobic filter bed tank C is characterized in that the pipe 6 is arranged.
[0007]
Here, the two reaction beds of the bioreaction layer 1 and the filtration layer 2 can be arranged side by side with the bioreaction layer 1 as a front filter bed and the filtration layer 2 as a rear filter bed. The aerobic filter bed tank C is arranged vertically (that is, forms a double bed) with the biological reaction layer 1 as the upper filter bed and the filter layer 2 as the lower filter bed.
[0008]
In addition, the air injection pipe 6 disposed below the air diffusion pipe 4b is an air injection in which the injected air flow forms a horizontal flow (that is, a flow parallel to the bottom surface) so that the SS settling on the bottom surface is sufficiently raised. It is assumed that the tube has a mouth 6a. Moreover, it is preferable that the location where the air injection port 6a is located is in the center of the bottom of the aerobic filter bed C or in the vicinity of the center so as to be in contact with the bottom (or at a position not separated from the bottom by 50 mm or more). .
[0009]
Further, in the aerobic filter bed C, a liquid of a transfer pump (usually an air lift pump) 5 is further provided below the filtration layer 2 or above the filtration layer 2 or below the biological reaction layer 1. It is preferable that a cleaning drainage outlet 5a serving as a suction inlet is disposed.
[0010]
The present invention secondly, a sewage purification tank equipped with the above-described aerobic filter bed tank, that is, an anaerobic filter bed tank (first chamber A and second chamber B) in order from the upstream, the above-described aerobic treatment tank C, A sewage septic tank comprising a sedimentation tank (or treated water tank) D and a disinfection tank E.
[0013]
[Action]
When washing the lower filter bed in the aerobic filter bed, the liquid in the lower filter bed is efficiently used by the horizontal jet stream from the air jet pipe (its air jet port) along with the vertical aeration from the diffuser pipe. Stir. Then, the SS present in the liquid is drawn out from the washing drainage outlet without sinking to the bottom surface, and returned to the first chamber of the anaerobic filter bed tank via the transfer pump (air lift pump) (see FIG. 1).
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an example of an aerobic filter bed tank according to the present invention, and FIG. 2 is a view of the aerobic filter bed tank of FIG. In these figures, an aeration air flow (arrow) at the time of cleaning is also appended.
The aerobic filter bed tank C is filled with a biological carrier (becomes a living organism, also called a contact material or a filter material) to form a filter bed. This filter bed is divided into an upper filter bed (biological reaction layer) 1 and a lower filter bed (filter layer) 2, and a water-permeable porous plate (biological carrier) between the upper filter bed 1 and the lower filter bed 2. Compartment that sandwiches water and air freely. Further, a water-permeable porous plate material is disposed on both the upper filter bed 1 and the lower filter bed 2 so as to prevent the biological carrier from flowing out.
[0015]
A diffuser pipe 4a is provided below the upper filter bed 1, a diffuser pipe 4b is also provided below the lower filter bed 2, and a liquid suction port of a transfer pump (air lift pump) 5 is provided below the aerobic filter bed tank C. A cleaning drain outlet 5a is provided.
Further, an air injection pipe 6 (air injection horizontal pipe 6b) having an air injection port 6a is disposed below the air diffusion pipe 4b, and an air injection flow parallel to the bottom surface can be created. Note that the diffuser holes formed in the diffuser tubes 4a and 4b are usually provided at the lower portion of the tube in order to prevent clogging due to sediment such as SS.
[0016]
Water treatment in the aerobic filter bed tank C is performed in the biological carrier in the presence of air (dissolved oxygen) aerated and introduced from the diffuser 4a in the upper filter bed (biological reaction layer) 1. It is aerobic treated by aerobic microorganisms that inhabit. That is, mainly, oxidation / decomposition of biochemical oxygen demand (BOD) and nitrification of ammonia proceed.
Further, in the lower filter bed 2, in the normal operation (operation other than during washing), aeration is not performed from the air diffusing tube 4b. While continuing the aerobic treatment while consuming the carry-over oxygen (dissolved oxygen) of the falling liquid from the upper filter bed 1, there is a function of efficiently capturing (filtering) SS using a stationary biological carrier. Therefore, the lower filter bed 2 is gradually clogged with the captured SS. In order to release this clogging, the aerobic filter bed C (particularly the lower filter bed 2) is periodically washed (usually once a day for about 1 to 30 minutes at night). At the time of this washing, aeration is performed from the air diffuser 4b provided under the lower filter bed 2, and at the same time, aeration is also performed from the air injection port 6a to release SS from the biological carrier. Simultaneously with the aeration or after the aeration, the cleaning waste water containing SS is extracted from the cleaning drain outlet 5a. An air lift pump is preferably used for this drawing.
[0017]
The aeration from the air injection port 6a of the air injection tube 6 is normally performed simultaneously with the aeration (that is, cleaning / suction) from the diffusion tube 4b, but may be performed prior to the aeration from the diffusion tube 4b. In this case, the SS that has settled on the bottom surface without being discharged at the time of washing the previous day is swollen in advance, and this is pulled out together with aeration (that is, washing / suction) from the aeration tube 4b.
Further, the aeration (that is, continuous aeration) from the air diffuser 4a of the upper filter bed 1 during the cleaning may be temporarily stopped during that time.
[0018]
Cleaning can be performed automatically by using a timer or the like. It is preferable that the time, time, and frequency can be set arbitrarily.
[0019]
Moreover, not only an air injection pipe as shown in FIG.1 and FIG.2, but an air injection pipe of various shapes can be used. 3 and 4 show another example of an air injection pipe and an aerobic filter bed tank. Each figure is a view of the aerobic filter bed tank as viewed from below the bottom surface. FIG. 3 shows an example in which the air injection pipe branches in the middle. FIG. 4 shows a small hole in the middle of the pipe in addition to the open end. This is an example where is opened.
[0020]
In addition, although the example of FIGS. 1-4 was taken as the example of the upper and lower two layers structure of the upper filter bed and the lower filter bed, it is also possible to set it as the serial structure of two horizontal rows instead of upper and lower.
[0021]
FIG. 5 is an example of a sewage purification tank (schematic configuration diagram) using the aerobic filter bed tank of the present invention.
This sewage septic tank has an anaerobic filter bed first chamber A, an anaerobic filter bed second chamber B, an aerobic filter bed C (having an upper filter bed 1 and a lower filter bed 2), and a treated water tank D from the upstream side. The sterilization tank E is divided into each tank.
The first chamber A and the second chamber B of the anaerobic filter bed tank can be filled with a biological carrier such as a mesh-like cylindrical filter medium, and the upper filter bed 1 and the lower filter of the aerobic filter bed tank C. The floor 2 can be filled with a biological carrier such as a sponge carrier.
The treated water tank D is provided with an air lift pump 5 necessary for washing the lower filter bed 2 of the aerobic filter bed tank C, and a liquid suction port of the air lift pump is provided at the lower part of the aerobic filter bed tank C. . The washing waste water extracted from here is returned to the first chamber A of the anaerobic filter bed tank. In addition, an air jet vertical pipe 6c is also disposed in the treated water tank D.
[0022]
An example of the cleaning operation is as follows. During normal operation of the sewage septic tank, air is supplied to the diffusing pipe 4 a below the upper filter bed 1, and no air is supplied to the diffusing pipe 4 b below the lower filter bed 2 and the air lift pump 5. At the time of washing, air is supplied to the air diffusion pipe 4b, the air lift pump 5 and the air injection pipe 6 below the lower filter bed 2.
[0023]
The air jet pipe 6 below the lower filter bed 2 is installed as follows. At the lower part of the aerobic filter bed C, an advection port 7 is provided on the side wall surface of the aerobic filter bed tank close to the treated water tank D, and a washing drain outlet 5a is arranged above the advection port, and this washing drain outlet 5a. The horizontal pipe 6b for air injection is inserted so that the bottom surface is made to flow from the treated water tank D side below. At that time, the air injection port 6a is arranged at the center of the bottom surface of the aerobic filter bed C. When air is supplied to the air injection pipe 6 and air is discharged from the air injection port 6a, the lower part of the lower filter bed 2 and the vicinity of the bottom of the aerobic filter bed tank C are stirred, and the SS is washed without staying at the bottom. It is pulled out from the cleaning drainage outlet 5a together with the drainage.
[0024]
According to the aerobic filter bed tank or the sewage purification tank of the present invention, even if the distance between the lower end of the lower filter bed and the bottom surface of the aerobic filter bed tank is long, SS is present at the bottom of the aerobic filter bed tank. it is not small to stay.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an aerobic filter bed tank according to the present invention. The aeration air flow at the time of washing is also indicated by an arrow.
FIG. 2 is a view of the aerobic filter bed tank of FIG. The arrow indicates the jet flow from the air jet port.
FIG. 3 is a view of another example of an aerobic filter bed tank according to the present invention as viewed from below the bottom surface. An example in which the air injection pipe branches on the way.
FIG. 4 is a view of another example of an aerobic filter bed tank according to the present invention as viewed from below the bottom surface. In addition to the open end of the air jet tube, a small hole is made in the middle of the tube.
FIG. 5 is a schematic configuration diagram of a sewage septic tank according to the present invention.
FIG. 6 is a schematic configuration diagram of a conventional aerobic filter bed tank.
[Explanation of symbols]
1: Upper filter bed (biological reaction layer) 2: Lower filter bed (filter layer)
3: Partition wall 4a: Air diffuser 4b: Air diffuser 5: Air lift pump 5a: Cleaning drain outlet (air lift pump suction port)
5b: Air lift pump pumping pipe 6: Air injection pipe 6a: Air injection port 6b: Horizontal pipe for air injection 6c: Vertical pipe for air injection 7: Advection port A: Anaerobic filter bed first chamber B: Anaerobic filter bed first Two rooms C: Aerobic filter bed D: Treated water tank E: Disinfection tank

Claims (4)

Has two filter beds biological reaction layer and the filtration layer, a aerobic filter bed vessel having a diffusing pipe, respectively under each filter bed, a lower diffusing pipe under side of the filtration layer, An air injection pipe is further disposed in a portion between the filtration layer and the bottom of the aerobic filter bed tank . The air injection pipe is a pipe having an air injection port that forms a horizontal flow of the injected air flow. An aerobic filter bed tank. 2. The aerobic of claim 1, wherein the two filter beds, the bioreactive layer and the filter layer, are arranged vertically to form a double bed with the bioreactive layer as the upper filter bed and the filter layer as the lower filter bed. Filter bed tank. The aerobic substance according to claim 1 or 2, wherein a washing drainage outlet serving as a liquid suction port of a transfer pump is further arranged below the filtration layer, or above the filtration layer or below the biological reaction layer. Filter bed tank. A sewage septic tank comprising an anaerobic treatment tank, an aerobic filter bed tank according to any one of claims 1 to 3, a treated water tank, and a disinfection tank.

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