JP2004223417A - Sewage treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sewage treatment apparatus constituted so as to easily keep the filtering function of a carrier filter bed in a carrier treatment tank by backward washing while enhancing the function. <P>SOLUTION: This sewage treatment apparatus is equipped with the carrier treatment tank E2 which is provided with the carrier filter beds E21 and E22 respectively formed by laminating a large number of carriers C1 and C2. A large number of the first carriers C1 comprising a material whose specific gravity is lower than that of water are floated and laminated in the carrier treatment tank E2 (E) to form the carrier filter bed E21 and a large number of the second carriers C2 comprising a material whose specific gravity is higher than that of water are deposited and laminated in the carrier treatment tank E (E2) to form the second carrier filter bed E22. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sewage treatment apparatus including a carrier treatment tank provided with a carrier filtration layer in which a number of carriers are stacked, and configured to be capable of filtering water to be treated.
[0002]
[Prior art]
Conventionally, as this type of sewage treatment apparatus, there has been known a sewage treatment apparatus in which a first carrier having a specific gravity slightly smaller than that of water is floated and laminated in a water treatment tank to form a carrier filtration layer.
On the other hand, there is also known a carrier in which a second carrier having a specific gravity slightly higher than that of water is settled and deposited in a water treatment tank to form a carrier filtration layer.
Such a carrier filtration layer has a function of biologically filtering the water to be treated that is advancing, and purifying the water to be treated with a microorganism film attached to the carrier. In addition, the solid component contained in the water to be treated can be removed, and plays a role of cleaning the water to be treated after being subjected to microbial treatment such as activated sludge treatment. The microbial membrane and the filtered solid components (hereinafter simply referred to as “solid components”) that are no longer needed in the carrier filtration layer are separated and removed from the carrier by backwashing the carrier and subjected to microbial treatment again. , And are stored so as to be able to be extracted as surplus sludge. At this time, the carrier is usually back-washed by supplying air bubbles from an air diffuser or the like provided in the carrier filtration layer.
In some cases, a carrier having a specific gravity lower than that of water is used in the carrier treatment tank in combination (see Patent Document 1). However, such a carrier is only used to flow in the tank by aeration or the like. It is not envisaged that both carriers are formed in the filtration layer.
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H11-147095
[Problems to be solved by the invention]
However, the carrier filtration layer provided in such a sewage treatment apparatus accumulates in a layered manner when the carrier floats upward or sinks downward, forming a carrier filtration layer. When the carrier filtration layer is formed, solid components contained in the water to be treated are captured by the carrier in the carrier filtration layer and filtered. However, since the filtered solid component is held in a state of being captured between the carriers, it is likely to be solidified while being in contact with the carriers. For this reason, the carriers are solidified together and tend to be a large lump. Then, the carriers are hard to move individually, so that the carriers are not loosened as a whole, and the solid components held between the carriers are less likely to be separated from the carriers. Therefore, the above-described effect of the backwashing is less likely to appear, and the carrier filtration layer is likely to be clogged as a whole.
If the clogging tends to occur, the flow of the water to be treated through the carrier filtration layer becomes worse. Then, the flow of the water to be treated and the filtration of sludge in the carrier treatment tank are biased. As a result, the water to be treated is not sufficiently purified, or the filtration function of the carrier filtration layer becomes insufficient.
Further, in order to avoid such a situation, when performing maintenance and inspection of the carrier filtration layer, the carrier can be easily inspected from the upper side of the carrier treatment tank when the carrier is floated and laminated upward, The situation where the solid components adhere to and accumulate on the carrier filtration layer can be confirmed, and a maintenance operation for removing such solid components can be easily performed. Therefore, the inconvenience that the carriers are integrated and solidified according to the adhesion of the solid components is less likely to occur, and the filtration function in the carrier treatment tank can be maintained at a high level.
However, if the carrier is only floating, it is easy to flow and is difficult to be densely laminated. Therefore, there is a problem that it is difficult to exert a sufficient biological filtration function unless a large amount of the carrier is used. , It is necessary to supply a large volume of air bubbles.
On the other hand, if the carrier is settled below the carrier treatment tank, it is difficult to visually inspect the carrier filtration layer, and thus it is difficult to easily inspect the carrier filtration layer.
Also, in any case, in order to efficiently backwash, if a large volume of bubbles is supplied to the carrier filtration layer or if frequent backwashing is performed, the water level of the carrier treatment tank fluctuates due to bubbles. There is also a problem that it becomes difficult to stabilize and the operating cost increases.
[0005]
Accordingly, an object of the present invention is to provide a sewage treatment apparatus in which the filtration function of a carrier filtration layer in a carrier treatment tank is enhanced while the filtration function is easily maintained by backwashing, in view of the above-mentioned drawbacks.
[0006]
[Means for Solving the Problems]
The characteristic configuration of the sewage treatment apparatus of the present invention for achieving this object is as follows:
Providing a carrier filtration layer in which a number of carriers are laminated, comprising a carrier treatment tank configured to be capable of filtering the water to be treated,
A large number of first carriers of a material having a lower specific gravity than water are floated and laminated in the carrier treatment tank to form a first carrier filtration layer,
A point that the second carrier filtration layer is formed by depositing and laminating a large number of second carriers made of a material having a specific gravity larger than that of water in the carrier treatment tank.
Further, it is preferable to provide a carrier flow device for flowing the carrier in the carrier treatment tank,
It is preferable that an air diffuser that diffuses air to the carrier filtration layer is provided to constitute the carrier flow device.
Further, it is preferable that the deposition height of the carrier filtration layer is １ ／ or less of the water level of the water to be treated in the carrier treatment tank,
It is more preferable that the first carrier filtration layer is formed below the water surface of the carrier treatment tank, and that the carrier filtration layer is provided with a treated water sprinkling pipe for dispersing and supplying the treated water from above.
[0007]
(Function and effect)
In other words, a water treatment apparatus provided with a carrier filtration layer in which a large number of carriers are laminated and provided with a carrier treatment tank configured to be capable of filtering the water to be treated is regenerated by simply backwashing a large number of carriers to perform a filtration function. Therefore, a carrier treatment tank suitable for advanced water treatment is formed.
When the carrier is formed of a material having a specific gravity smaller than that of water, the carrier floats on water and floats above the carrier treatment tank. Then, a large number of first carriers are gathered above the carrier treatment tank to form a first carrier filtration layer.
[0008]
Incidentally, in the case of the carrier filtration in the first carrier filtration layer, if the water to be treated is configured to be filtered downward from above, the filtered solid component is mainly held on the upper surface of the carrier filtration layer, Inspection work becomes easy. Further, the first carrier is configured to be easily moved downward, and the flow of the water to be treated is in a direction to move the carrier downward, so that the carrier is filtered during the filtration of the water to be treated, It means that it is always vibrated. Therefore, the carrier to which the solid component adheres is difficult to be integrated with the adjacent carrier, and the carrier having a large specific gravity due to the large amount of the solid component moves to the lower part of the carrier filtration layer, and the solid component adheres little. Slow circulation of the carrier can be expected in that a new carrier that has not moved to the upper part of the carrier filtration layer, and it is considered that the function of filtering solid components is easily maintained at a high level.
[0009]
Conversely, if it is configured to filter upward from the bottom, while filtering the solid component, when the filtered solid component is peeled off from the carrier, it is easy to drop downward, so that the second component described below is used. The solid component separated by the carrier filtration layer can be captured again. Therefore, it is considered that the solid component hardly accumulates in the first carrier filtration layer, and the possibility that the separated solid component is mixed into the filtered water to be treated is reduced.
[0010]
Further, since a second carrier filtration layer formed by stacking and laminating a large number of second carriers having a specific gravity greater than that of water in the carrier treatment tank is provided separately from the previous carrier filtration tank, Therefore, even if the water to be treated passes in either the upward or downward direction, the water passes through the carrier filtration layer twice. The thickness of the carrier filtration layer required for filtering solid components from the water to be treated is determined by the quality of the water to be treated, but if this thickness is to be divided into two layers, the thickness per layer is set to be small. And the filtration resistance per layer can be reduced. In addition, since the position where the captured solid component adheres is dispersed, clogging hardly occurs, and the flow of the water to be treated becomes smooth. Therefore, even the entire carrier filtration layer can exhibit a sufficient biofiltration function with a small amount of carrier, and does not require large power or the like even when the carrier is backwashed and regenerated. Therefore, the treatment efficiency of the water to be treated is easily maintained at a high level, and the maintenance and inspection of the carrier treatment tank can be labor-saving.
[0011]
In addition, if a carrier flow device for flowing the carrier in the carrier processing tank is provided, the carrier flow device promotes collision between the carriers simply by flowing the carriers, thereby separating solid components from the carrier. Can be. Further, the separated sludge usually precipitates because its specific gravity is larger than water, and the separated sludge is less likely to re-attach to the carrier as compared with the carrier filtration layer settled and deposited. Therefore, the filtration function of the carrier filtration layer can be easily restored, and a stable function can be maintained even during long-term use.
[0012]
When the carrier flow device is configured by providing an air diffusing device for diffusing air to the carrier filtration layer, the above-described high effect can be exhibited with a small amount of power because the carrier fluidizing device is made to flow by the air diffusing. In addition, according to the air diffuser, the solid component is separated from the carrier by collision of air bubbles, and the carrier can be efficiently regenerated.
Since the separated solid components are circulated in the carrier treatment tank, the solid components can be easily transported even when performing biological treatment, sludge extraction treatment, and the like again.
[0013]
In the case described above, if the water to be treated is filtered downward from the top, the solid component is removed first, and the carrier filtration layer to which the solid component mainly adheres is located on the upper side. The work is easy and convenient. Further, in this case, even if the solid component is peeled off from the first carrier filtration layer formed on the upper portion, the solid component can be captured again by the second carrier filtration layer below. Therefore, precise solid component filtration becomes possible.
[0014]
In addition, the deposition height of the carrier filtration layer is set to be approximately 以下 or less of the water level of the water to be treated in the carrier treatment tank in order to secure a sufficient space for flowing the carrier during the backwashing. Preferably, in the carrier filtration layer of the present invention, the first and second carrier filtration layers are relatively small in the amount of carrier, and since it is easy to impart sufficient functions, it is easy to realize this set dimension, and the carrier filtration Since the intermediate hollow portion where the layer is not formed can be used as an expansion and a flow space of the carrier at the time of back washing of the carrier, maintenance can be performed efficiently, and operation costs and the like can be reduced.
[0015]
Further, when the first carrier filtration layer is formed below the surface of the carrier treatment tank and a treated water sprinkling pipe for dispersing the treated water from above is provided, the first carrier filtration layer is supplied to the carrier filtration layer. The water to be treated is supplied evenly to the entire carrier filtration layer. Then, when the water to be treated is supplied in a concentrated manner at one location, the solid component is concentrated and adhered only to a part of the carrier filtration layer, whereas the carrier is likely to be clogged and integrated. This is preferable because the filter layer is uniformly used as a whole and the carrier is less likely to be clogged and integrated. Further, since the water to be treated supplied to the carrier filtration layer is dispersed and hardly concentrated at one place, the carrier filtration layer is formed under the water surface of the carrier treatment tank. The inconvenience that the part is constantly circulated by the water flow and it is difficult to exhibit the filtering function can be avoided. Incidentally, when a support member for regulating the floating of the carrier is provided below the water surface, a carrier supporting portion for restricting the floating of the carrier is provided above the carrier processing tank, and the carrier filtration layer is formed below the carrier supporting portion. In this case, since the carrier floats and is held by the carrier supporting portion, the carrier can be guided so as not to be largely unevenly deposited. For this reason, it is conceivable to avoid concentration of the solid component on the carrier by such a carrier support portion, but in this case, the carrier support member or the like makes it difficult to visually recognize the carrier, resulting in reduced maintenance convenience. It is considered that the disadvantage that the support member itself is clogged is likely to occur. Therefore, if the first carrier filtration layer is formed below the surface of the carrier treatment tank, and if the carrier filtration layer is formed below the surface of the carrier treatment tank, such inconveniences are less likely to occur. .
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 1, the sewage treatment apparatus of the present invention constitutes a septic tank including a carrier treatment tank E. The septic tank is provided so that water to be treated flows through the first anaerobic filter bed tank, the second chambers N1, N2, the carrier treatment tank E, and the treated water tank T in this order from the upstream side.
[0017]
The anaerobic filter bed first chamber N1 is provided with a honeycomb net-shaped anaerobic filter bed F1 inside a water treatment chamber that receives and stores raw water to be treated. The water treatment chamber is provided with an air lift pump A1 for quantitatively transferring the to-be-processed water once stored to the anaerobic filter tank second chamber N2, and is internally provided.
[0018]
The anaerobic filter bed tank second chamber N2 receives the water to be treated from the anaerobic filter tank first chamber N1, temporarily stores the anaerobic filter bed tank N2, and anaerobically treats the biologically anaerobic filter bed F2 by a large number of baskets. It is constituted by a carrier in the shape of a circle. The partition wall W2, which partitions between the anaerobic filter bed second chamber N2 and the carrier treatment tank E, is provided with an advection port Wa through which the water to be treated passes, and a treatment port advected from the advection port Wa. A flow control plate Wb for controlling the amount of water in accordance with the water level of the anaerobic filter bed second chamber N2 is provided.
Of the water to be treated that has flowed into the anaerobic filter bed tank first chamber N1, the anaerobic filter bed tank first chamber and the partition wall W1 partitioning the second chambers N1 and N2 with the abnormal inflow of the water to be treated. The water to be treated that has flowed into the anaerobic filter bed tank second chamber N2 is prevented from flowing into the carrier treatment tank E by the flow suppression plate Wb, and is gradually transferred. One of the chambers is stored in the second chambers N1 and N2, and functions to adjust the flow rate so that the water to be treated is constantly transferred.
[0019]
The carrier treatment tank E was aerobically treated in the carrier flow section E1 and the carrier flow section E1 for aerobically treating the water to be treated, together with the short pipe-shaped carrier C caused to flow by aeration. And a carrier filtration unit E2 for biologically filtering the water to be treated.
The carrier C has a specific gravity of about 1.08, and is filled in an amount occupying approximately 25 to 35% of the volume of the carrier flowing section E1. Note that the carrier C does not flow out of the carrier flowing portion E1 due to the net-shaped carrier supporting portions S1 and S2 provided above and below the carrier flowing portion E1, and satisfactorily flows inside the carrier flowing portion E1. It is held so that it can flow.
[0020]
In the carrier flowing section E1, the water to be treated flows along with the sludge and is aerobically biologically treated by the bubbles supplied by the diffuser D. The water to be treated, which has been cleaned by the biological treatment, is transferred to the carrier filtration unit E2 by the air lift pump A2.
The air lift pump A2 adjoins a vertical pipe A21 extending from the upper part to the lower part of the carrier flow part, a measuring cell A22 provided on the upper part of the vertical pipe, and water to be treated pumped to the measuring cell A22. And a horizontal pipe A23 for transfer to the carrier filtration unit E2.
The water to be treated, which is transferred to the carrier filtration unit E2 by the air lift pump A2, is quantitatively dispersed and supplied to the upper surface of the carrier filtration unit E2 by the treated water sprinkling pipe B provided above the carrier filtration unit E2.
[0021]
The carrier filtration unit E2 receives the water to be treated supplied from above, and a large number of short pipe-shaped water treatment chambers in which the filtered water to be treated is transferred from the lower treated water advancing unit E23 to the treated water tank T. It is configured to accommodate the carriers C1 and C2. The water treatment chamber is provided with a net-shaped carrier support portion S3 slightly above the accommodated treated water advancing section E23 to suppress outflow of the carriers C1 and C2 to the adjacent water treatment chamber.
[0022]
The carrier has a first carrier C1 lighter than water having a specific gravity of about 0.98 and a second carrier C2 heavier than water having a specific gravity of about 1.08, and is provided in a carrier filtration section E2 sandwiched between a water surface and a carrier support section S3. An amount occupying approximately 20-25% of the volume is filled.
Thereby, the first carrier filtration layer E21 in which the first carrier C1 floats and accumulates is formed below the water surface in the carrier flow section E2, and the second carrier C2 is formed on the lower carrier support section S2. The second carrier filtration layer E22 that has settled and deposited is formed.
Normally, the first and second carrier filtration layers E21 and E22 biologically filter the supplied water to be treated while the carriers C1 and C2 are deposited. The water to be treated, which has been purified by biological filtration, is transferred to the treatment water tank T as treated water, and the first and second carriers C1 and C2 constituting the first and second carrier filtration layers E21 and E22 are provided with the treated water. The solid component adheres due to biological filtration.
In the carrier filtration unit E2, air bubbles are supplied to the first and second carriers C1 and C2 deposited on the respective carrier filtration layers E21 and E22 to flow into the carrier filtration unit E2, First and second air diffusers D1 and D2 are provided, which allow the carriers C1 and C2 to flow and loosen, and further remove and regenerate and regenerate solid components adhered by collision between the first and second carriers C1 and C2. To form a carrier flow device. Preferably, the first air diffuser is provided slightly below the first carrier filtration layer.
Since the deposition height of the first and second carriers C1 and C2 is 40 to 50% of the height of the carrier filtration unit E2, of the carrier flow device, the height of the second air diffusion device D2 It is easily and efficiently fluidized by aeration, and the first and second carriers C1 and C2 constituting the first and second carrier filtration layers E21 and E22 are backwashed and regenerated, and the biological filtration efficiency is always high. There are things that can be maintained. Further, in the carrier filtration unit E2, since the water to be treated is filtered downward from above, the solid component is preferentially captured by the first carrier filtration layer. Therefore, when the first air diffuser D1 is operated, only the first carrier filtration layer can be preferentially backwashed and regenerated, which is useful for long-term stable operation of the carrier filtration unit E2. Can be Further, with such a configuration, the treatment water purification function is greatly improved, and the nitrification function is enhanced. Further, conventionally, in a sewage treatment apparatus that has been operated using a carrier treatment tank provided with only one of the first and second carrier filtration layers, the transparency is 30 to 35 cm, the BOD is 15 to 20 mg / L, and the COD is 30 mg / L. The treated water that could only be purified to a degree was treated with the above-mentioned sewage treatment apparatus of the present invention, and it was found that the degree of transparency could be reduced to about 45 to 50 cm, BOD 5 to 10 mg / L, and COD 15 mg / L. It has been found that very advanced water treatment is possible.
[0023]
In addition, an air lift pump A3 for pumping water to be treated from below the first and second carrier filtration layers E21 and E22 is provided to remove solid components and the like generated by regeneration of the carrier filtration layers E21 and E22. It is configured so that it can be returned to the first room N1.
The air lift pump A3 includes a vertical tube A31 extending from above the carrier filtration unit E2 to below the carrier filtration unit E2, a measuring box A32 provided above the vertical tube A31, and a measuring box A32. And a horizontal pipe A33 for transferring the to-be-treated water pumped to the first anaerobic filter bed tank N1. Further, a horizontal pipe A34 for returning the excess water to be treated to the metering box of the air lift pump A2 is provided, and the water to be treated is constantly circulated.
Thus, the air lift pump A3 constantly pumps up the filtered treated water and returns the treated water to the first anaerobic filter bed tank N1 for denitrification. Furthermore, while reducing the nitrogen content in the treated water, a part of the treated water is returned to the carrier filtration unit E1, and the re-filtration of the filtered treated water is repeated, whereby the removal of solid components from the treated water is more effectively performed. Done. Also, at the time of back washing of the carrier filtration layers E21 and E22, almost all solid components are returned to the first anaerobic filter bed tank N1 by rapidly pumping and returning exfoliated sludge and the like generated by the back washing. Prevents solid components from advancing to T.
[0024]
The treated water that has passed through the first and second carrier filtration layers E21 and E22 flows through the treated water advancing section E23 to the treated water tank T. In the treated water tank T, while temporarily storing the treated water, solid components in the treated water that could not be removed in the carrier treatment tank E were precipitated, and only the supernatant was provided above the treated water tank T. After being disinfected through the disinfecting section Q, it is configured to be discharged outside the sewage treatment apparatus.
[Brief description of the drawings]
FIG. 1 is a vertical sectional side view of a septic tank. FIG. 2 is a vertical sectional front view of a main part of the septic tank. FIG. 3 is a cross-sectional plan view of a main part of the septic tank.
C1 first carrier C2 second carrier E2 carrier treatment tank E21 first carrier filtration layer E22 second carrier filtration layer

Claims (5)

A sewage treatment apparatus provided with a carrier filtration tank provided with a carrier filtration layer in which a large number of carriers are laminated, and a water to be treated is configured to be capable of being filtered.
A large number of first carriers of a material having a lower specific gravity than water are floated and laminated in the carrier treatment tank to form a first carrier filtration layer,
A sewage treatment apparatus in which a large number of second carriers having a specific gravity higher than that of water are deposited and laminated in the carrier treatment tank to form a second carrier filtration layer. The sewage treatment apparatus according to claim 1, further comprising a carrier flow device that causes the carrier to flow in the carrier treatment tank. The sewage treatment apparatus according to claim 2, wherein an air diffuser that diffuses air to the carrier filtration layer is provided to constitute the carrier flow device. The sewage treatment apparatus according to any one of claims 1 to 3, wherein a deposition height of the carrier filtration layer is equal to or less than の of a water level of the water to be treated in the carrier treatment tank. The first carrier filtration layer is formed below the surface of the carrier treatment tank, and a treated water sprinkling pipe for dispersing and supplying treated water from above is provided on the carrier filtration layer. The sewage treatment apparatus according to claim 1.

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