JP2015226886A - Down-flow filter tank body, method for manufacturing down-flow filter tank body, and method for modifying down-flow filter tank body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel down-flow filter tank body capable of preventing the blowup of the fragments at a back washing time properly, even if a water collecting apparatus is broken, a method for the down-flow filter tank, and a method for modifying the down-flow filter tank.SOLUTION: A down-flow filter tank 1 comprises: a down-flow filter tank body 2; a water collecting apparatus 3 dispersed on the bottom of the down-flow filter tank body 2; and a filter layer 4 composed of granules deposited on the water collecting apparatus 3. Treatment water is filtered by passing it from the upper side to the lower side of the filter layer 4. A water-permeable sheet 5 is laid along the boundary between the upper face of the water collecting apparatus 3 and the filter layer 4.

Description

  The present invention provides a downflow filtration tank for filtering the water to be treated by passing the water to be treated from the upper side to the lower side of the filter layer, and a method for producing the downward flow filtration tank, and The present invention relates to a method for repairing a downward flow filtration tank.

  A water purification plant is a water supply facility that supplies raw water to drinking water by purifying and disinfecting raw water taken from rivers and groundwater.

  Conventionally, when purifying raw water at the water purification plant, a filtration process using a downward flow filtration tank called a “filter pond (filter pond)” has been performed.

  The downward flow filtration tank comprises a filtration tank body, a water collecting device installed at the bottom of the filtration tank body, and a filter layer made of particulate matter deposited on the water collecting device. In addition, by removing the raw water introduced into the filtration tank body from the upper side to the lower side of the filter layer, impurities such as suspended matter and microorganisms contained in the raw water are removed, and the water collecting device In this way, the filtered water is transferred to the next treatment facility.

  And in the filtration process using this downward flow filtration tank, since the impurities in the raw water are collected by the filter layer, if the filtration process is repeatedly executed, impurities are accumulated in the filter layer. For this reason, a backwashing operation is periodically performed in which a medium such as air or purified water is press-fitted into the water collecting device to remove impurities accumulated in the filter layer.

  However, during the backwashing operation, the water collecting device may be damaged by the press-fitted medium. Further, the water collecting device may be damaged due to an earthquake or the like. When the backwashing operation is performed while the water collector is damaged, debris of the water collector, a lump of air larger than the expected amount, and purified water are blown up toward the filter layer, and the filter layer has a large amount. Damage is done. Moreover, the granular material which comprises the said filter layer falls in the said water collection apparatus from the defect | deletion hole which arose in the said water collection apparatus by the blowing up of the said fragment, and the said water collection apparatus is obstruct | occluded. When the downward flow filtration tank is in such a state, a large-scale repair work requiring a great cost is required.

  In view of this point, recently, a porous plate is arranged above the water collecting block with a certain interval, and an air injection device for backwashing is arranged between the water collecting block and the porous plate. A water collecting apparatus has been developed (for example, see Patent Document 1 below).

JP 2013-71096 A

  However, in constructing a downward flow filtration tank using the water collecting device described in Patent Document 1, sand or the like is placed on the perforated plate arranged at a predetermined interval above the water collecting device. The filter layer is formed by depositing the particulate matter. Therefore, in the water collecting device, it is necessary to support the porous plate with a member having considerable rigidity, and the porous plate itself needs to have considerable rigidity. That is, the water collecting apparatus described in Patent Document 1 requires a considerable manufacturing cost.

  The present invention has been completed in view of the technical problem, and is capable of suitably preventing the blow-up of the debris of the water collecting device during backwashing work even if the water collecting device is damaged. It aims at providing the manufacturing method of a downward flow filtration tank, a downward flow filtration tank, and the repair method of a downward flow filtration tank.

  In order to solve the technical problem, the downward flow filtration tank of the present invention includes a filtration tank main body, a water collecting device installed at the bottom of the filtration tank main body, and a granular material deposited on the water collecting device. A downward flow filtration tank for filtering the water to be treated by allowing the water to be treated to flow from the upper side to the lower side of the filter layer. Then, a water-permeable sheet is laid along the boundary between the upper surface of the water collecting device and the filter layer (hereinafter referred to as “the present invention filtration tank”).

  In the filtration tank of the present invention, the water-permeable sheet is preferably formed of a metal mesh, punching metal, or a porous sheet made of a polymer material.

  In the filtration tank of the present invention, it is preferable that the water-permeable sheet has an opening of 3 to 10 mm.

  In the filtration tank of the present invention, the water-permeable sheet is preferably a wire mesh having a wire diameter of 0.5 to 3 mm.

  The manufacturing method of the downward flow filtration tank of this invention is a manufacturing method of the downward flow filtration tank which filters the said to-be-processed water by allowing the to-be-processed water to flow from the upper side of a filter layer toward the lower side. A water collecting device forming step of forming a water collecting device at the bottom of the filtration tank body, a water permeable sheet laying step of laying a water permeable sheet on the upper surface of the water collecting device, and a granular shape on the water permeable sheet And a filter layer forming step of forming the filter layer by depositing an object (hereinafter referred to as “the production method of the present invention”).

  The method of repairing the downward flow filtration tank of the present invention includes a filtration tank main body, a water collecting device installed at the bottom of the filtration tank main body, a filter layer made of particulate matter deposited on the water collecting device, And a method of repairing a downflow filtration tank for filtering the water to be treated by passing the water to be treated from the upper side to the lower side of the filter layer. A filter layer removing step of removing a layer, a water permeable sheet laying step of laying a water permeable sheet on the upper surface of the water collecting device exposed by removing the filter layer, and the particulate matter on the water permeable sheet Or a filter layer forming step of forming a filter layer by depositing other granular materials (hereinafter referred to as “the present invention repair method”).

  According to the present invention, even if the water collecting device is damaged, it is possible to suitably prevent the fragments of the water collecting device from being blown up during the backwashing operation.

FIG. 1 is a front view (a) and a side view (b) showing the filtration tank of the present invention in a cross-sectional state. FIG. 2 is a schematic diagram showing the water purification plant in a partially sectional state. FIG. 3 is a perspective view showing the water collecting block. 4A and 4B are perspective views showing a state in which a water collecting device is installed at the bottom of the filtration tank main body. FIGS. 5A and 5B are perspective views showing a state in which a water-permeable sheet is laid on a water collecting block constituting the water collecting device. FIG. 6 is a flowchart showing the steps of the manufacturing method of the present invention. FIG. 7 is a flowchart showing the steps of the repair method of the present invention.

  Hereinafter, although the form for implementing this invention is demonstrated based on drawing, this invention is not limited to this embodiment.

<Invention Filtration Tank 1>
In FIG. 1, this invention filtration tank 1 which concerns on embodiment is shown. The filtration tank 1 of the present invention includes a filtration tank body 2, a water collecting device 3, a filter layer 4, and a water-permeable sheet 5.

  In addition, the said filtration tank 1 of this invention is used as a "filter pond" in the water purification plant 10 shown in FIG. In addition to the filtration tank 1 of the present invention, the water purification plant 10 includes a water intake tower 11, a landing well 12, a chemical mixing basin 13, a flock formation basin 14, a sedimentation basin 15, a chlorine injection facility 16, and a water basin. 17. That is, the water purification plant 10 has a mechanism for purifying and disinfecting water to be treated (raw water) taken in via the intake tower 11 while sequentially moving to each facility.

-Filtration tank body 2-
The filtration tank body 2 is a tank having an upper end opened. An intake path 21 that communicates with the settling basin 15 is provided at the upper part of the filtration tank body 2, and a drainage path 22 that communicates with the chlorine injection facility 16 is provided at the lower part of the filtration tank body 2. Provided (see FIG. 1A).

-Water collector 3-
In the present embodiment, the water collecting device 3 is constructed by a plurality of water collecting blocks 31 installed at the bottom of the filtration tank body 2 (see FIG. 1B).

  As shown in FIG. 3, the water collecting block 31 is a hollow body having an overall shape of a quadrangular prism, and four flow paths are formed by a partition plate 30 that partitions the internal space into a cross. Hereinafter, of these four channels, the two channels on the upper side in the figure are referred to as “upper channel (32)”, and the two channels on the lower side are referred to as “lower channel (33)”. Called.

  The ceiling wall of the water collecting block 31 is provided with a plurality of orifice holes 34 that communicate with the upper flow path 32, and the partition plate 30 that partitions the internal space of the water collecting block 31 in the horizontal direction includes the lower side A water collecting hole 35 communicating with the flow path 33 is provided.

  As shown in FIG. 4A, after the water collecting blocks 31 are laid in a plurality of rows on the bottom of the filtration tank body 2, as shown in FIG. The water collecting device 3 is configured by filling the existing gap with a weathering material 300 such as mortar.

-Filter layer 4-
The filter layer 4 is made of granular material deposited on the water collecting device 3. In the present embodiment, two types of gravel and sand are used as the granular material, and the filter layer 4 includes a gravel layer 41 made of gravel deposited on the water collecting device 3, and And a sand layer 42 made of sand deposited on the gravel layer 41 (see FIG. 1).

-Water-permeable sheet 5-
The water-permeable sheet 5 is laid along the boundary between the upper surface of the water collecting device 3 and the filter layer 4.

  In the present embodiment, a wire net having a wire diameter of 1.2 mm and an opening of 5 mm is used as the water-permeable sheet 5. As shown in FIG. 5, the water-permeable sheet 5 is laid on the upper surface of the water collecting device 3, and the portion in contact with the inner wall surface is fixed to the inner wall surface (or the filter tank body 2) by the fixing member 6. The water collecting device 3) is fixed.

  And if the said filter layer 4 is formed on the said water-permeable sheet 5 laid on the said water collection apparatus 3, the said water-permeable sheet 5 will be the upper surface of the said water collection block 31, and the said filter layer 4 It will be arranged along the boundary.

  In this embodiment, by using a plurality of the water permeable sheets 5, the entire upper surface of the water collecting device 3 is covered with the water permeable sheet. As described above, when a plurality of the water-permeable sheets 5 are used, it is preferable that the side sides of the adjacent water-permeable sheets 5 are overlapped and the overlapped portion is bound by a cord body such as a wire.

  The filtration tank 1 of the present invention having the above configuration allows the water to be treated introduced into the filtration tank body 2 through the intake channel 21 to flow from the upper side to the lower side of the filter layer 4. Then, impurities such as suspended matter and microorganisms contained in the water to be treated are removed, and the next treatment facility (in the present embodiment, the chlorine injection facility 16) is passed through the water collecting device 3 and the drainage channel 22. It is structured to be transferred to.

  And in the filtration process using the said filtration tank 1 of this invention, in order to collect the impurities in to-be-processed water by the said filter layer 4, if a filtration process is repeatedly performed, an impurity will be accumulate | stored in the said filter layer 4. Go. Therefore, it is necessary to perform a back-washing operation to periodically pressurize a medium such as air or purified water into the water collecting device 3 to remove impurities accumulated in the filter layer 4.

  In carrying out this backwashing operation, the filtration tank 1 of the present invention is configured such that the water-permeable sheet 5 extends along the boundary between the upper surface of the water collecting block 31 constituting the water collecting device 3 and the filter layer 4. Therefore, even if a part of the water collecting block 31 constituting the water collecting device 3 is damaged, a piece of the water collecting block 31 is removed during the back washing operation. Blowing up toward 4 can be suitably prevented.

  In the present embodiment, a wire mesh having a wire diameter of 1.2 mm and an opening of 5 mm is used as the water-permeable sheet 5, but as the water-permeable sheet 5, the water that has passed through the filter layer 4 is It has enough openings to be quickly introduced into the water collecting device 3 and can prevent the fragments of the water collecting block 31 from blowing up toward the filter layer 4 during backwashing. There is no particular limitation as long as it has rigidity. Other examples of the water-permeable sheet 5 include a net made of a fiber material, a punching metal, a porous sheet made of a polymer material, and the like.

  The opening of the water-permeable sheet 5 is preferably in the range of 3 to 10 mm (more preferably 4 to 8 mm), and the opening ratio is in the range of 15 to 75% (more preferably 55 to 70%). preferable. When using a wire mesh as the water-permeable sheet 5 as in the present embodiment, the wire diameter is 0.5 to 3 mm (more preferably 0.8 to 2.0 mm, still more preferably 1.0 to 1.75 mm) is preferable.

  The thickness of the punching metal is preferably in the range of 0.5 to 2.00 mm from the viewpoints of strength, handleability and workability, and the thickness of the porous sheet made of a polymer material. Is preferably in the range of 0.5 to 10 mm (preferably 1 to 5 mm) for the same reason. Examples of the porous sheet made of a polymer material include those made of natural or synthetic resin or rubber.

  In the present embodiment, a portion of the laid water-permeable sheet 5 that is in contact with the inner wall surface of the filtration tank body 2 is fixed by the fixing member 6, but the water-permeable sheet 5 is the filter layer 4. Therefore, it may be simply laid on the water collecting device 3.

  Further, in the present embodiment, the filter layer 4 has a multi-layer structure composed of the gravel layer 41 and the sand layer 42, but the filter layer 4 includes only the gravel layer 41 or the sand layer 42. It may be a single layer structure.

  In the case where the filter layer 4 has a multilayer structure as in the present embodiment, the water-permeable sheet 5 is interposed also at the boundary of each layer, so that the granular material constituting each layer at the time of performing the backwashing operation. It is preferable not to mix up.

  In addition, in the present embodiment, the water collecting device 3 is constituted by the water collecting block 31, but the water collecting device 3 collects the water that has passed through the filter layer 4, and The structure is not particularly limited as long as the structure can be transferred to the facility.

  By the way, in this embodiment, although the said filtration tank 1 of this invention is used as a filtration pond of the said water purification plant 10, the said filtration tank 1 of this invention is used as a processing facility of the said water purification plant 10. It is not limited. The said filtration tank 1 of this invention can be used conveniently, for example in the processing equipment in a sewage treatment plant, and other water treatment facilities.

<Production method of the present invention>
The said filtration tank 1 of this invention can be manufactured with this invention method. In manufacturing the said filtration tank 1 by this invention manufacturing method, as shown to the flowchart of FIG. 6, a water collecting apparatus formation process (S1), a water-permeable sheet laying process (S2), and filter layer formation Step (S3) is performed.

-Water collecting device formation process (S1)-
In the water collecting device forming step (S1), the water collecting device 3 is formed at the bottom of the filtration tank body 2 (see FIG. 4).

-Water-permeable sheet laying process (S2)-
In the water permeable sheet laying step (S2), the water permeable sheet 5 is laid on the upper surface of the water collecting device 3 (see FIG. 5).

-Filter layer formation step (S3)-
In the filter layer forming step (S3), the filter layer 4 is formed by depositing particulate matter on the water-permeable sheet 5 (see FIG. 1).

<Invention modification method>
Moreover, this invention filtration tank 1 which has the said structure consists of the filtration tank main body 2, the water collection apparatus 3 installed in the bottom part of the said filtration tank main body 2, and the granular material deposited on the said water collection apparatus 3. FIG. An existing downflow filtration tank comprising the filter layer 4 can also be constructed by refurbishing with the refurbishing method of the present invention. In refurbishing the existing downflow filtration tank by the present modification method, as shown in the flowchart of FIG. 7, the filter layer removing step (S4), the water-permeable sheet laying step (S5), and the filter layer Forming step (S6).

-Filter layer removal step (S4)-
In the filter layer removing step (S4), the filter layer 4 existing in the existing downward flow filtration tank is removed. In addition, when the damage etc. have arisen in the water collecting apparatus 3 exposed by removing the filter layer 4, it is preferable to repair a damaged part.

-Water permeable sheet laying process (S5)-
In the water-permeable sheet laying step (S5), the water-permeable sheet 5 is laid on the upper surface of the water collecting device 3 exposed by removing the filter layer 4 (see FIG. 5).

-Filter layer formation step (S6)-
In the filter layer forming step (S6), the filter layer 4 is formed by depositing particulate matter on the water-permeable sheet 5 (see FIG. 1). In addition, the granular material used when performing this process may reuse the removed granular material in the said filter layer removal process (S4), and may use another granular material.

  It should be noted that the present invention can be implemented in various other forms without departing from the spirit or main features thereof. Therefore, the above-mentioned embodiment is only a mere illustration in all points, and should not be interpreted limitedly. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  The present invention is suitable as a downward flow filtration tank that can suitably prevent blowing up of fragments of the water collecting block during backwashing work even if the water collecting block constituting the water collecting device is damaged. Used for.

1 Filtration tank (downward flow filtration tank)
2 Filtration tank body 3 Water collecting device 31 Water collecting block 4 Filter layer 5 Water-permeable sheet 10 Water purification plant

Claims (6)

A filtration tank body;
A water collecting device installed at the bottom of the main body of the filtration tank;
A filter layer made of particulate matter deposited on the water collecting device;
Comprising
A downflow filtration tank for filtering the water to be treated by passing the water to be treated from the upper side to the lower side of the filter layer,
A downflow filtration tank, wherein a water-permeable sheet is laid along a boundary between the upper surface of the water collecting device and the filter layer. In the downward flow filtration tank according to claim 1,
A downflow filtration tank in which the water-permeable sheet is made of a porous sheet made of a wire mesh, punching metal, or polymer material. In the downflow filtration tank according to claim 1 or 2,
The downward flow filtration tank in which the water-permeable sheet has an opening of 3 to 10 mm. In the downward flow filtration tank according to any one of claims 1 to 3,
The downward flow filtration tank in which the water-permeable sheet is a wire net having a wire diameter of 0.5 to 3 mm. A method of manufacturing a downward flow filtration tank for filtering the water to be treated by passing the water to be treated from the upper side to the lower side of the filter layer,
A water collecting device forming step of forming a water collecting device at the bottom of the filtration tank body;
A water permeable sheet laying step of laying a water permeable sheet on the upper surface of the water collecting device;
A filter layer forming step of forming the filter layer by depositing particulate matter on the water-permeable sheet;
The manufacturing method of the downward flow filtration tank characterized by performing these. A filtration tank body;
A water collecting device installed at the bottom of the main body of the filtration tank;
A filter layer made of particulate matter deposited on the water collecting device;
Comprising
A method of repairing a downflow filtration tank for filtering the water to be treated by passing the water to be treated from the upper side to the lower side of the filter layer,
A filter layer removing step of removing the filter layer;
A water permeable sheet laying step of laying a water permeable sheet on the upper surface of the water collecting device exposed by removing the filter layer;
A filter layer forming step of forming a filter layer by depositing the granular material or other granular material on the water-permeable sheet;
A method for refurbishing a downward flow filtration tank, characterized in that

Images