JP2006272225A - Sand filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sand filter capable of certainly solving clogging of a water collecting material over the whole length. <P>SOLUTION: The sand filter 1 is provided with a container 2 charged with waste water from the upper part, the water collecting material 3 formed of cylindrical woven fabric having a self-keeping property by using thread having bending resilience in a part of the weft and housed in the container 2, a sand layer 4 filling the upper side of the water collecting material 3 in the container 2 and an air tube 16 inserted in the water collecting material 3 over the whole length. Thereby, high-pressure air can be supplied even into the inner part of the water collecting material 3 through the air tube 16 and clogging is certainly solved even in the case of generating clogging in the water collecting material 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sand filtration device for filtering water to be treated such as waste water generated at a construction site through a sand layer.

  Wastewater containing a large amount of earth and sand is generated at sites such as excavation work for tunnels and pile holes, and dredging work for rivers and lakes. Conventionally, such wastewater is transported to treatment plants by tank lorries. There are many cases. However, if wastewater containing a large amount of earth and sand is transported as it is, the amount of wastewater is large, and so transporting it takes a lot of cost and labor. Therefore, it is preferable to reduce the amount of waste water by filtering the waste water at the construction site using a filtration device before transportation.

  As a conventional general filtration device, for example, a filtration device as described in Patent Document 1 is known. This filtration device has a sealed tank and a sand layer filled in the tank, filters the water to be treated introduced from above the tank through the sand layer, and discharges the filtered water from below the tank. Is configured to do.

  However, since the conventional filtration apparatus as described in Patent Document 1 has a structure in which a sand layer or the like is disposed in a sealed tank, it necessarily has a large structure. Since such a filtration device is not easily assembled on site, it is sometimes necessary to transport a large pre-assembled filtration device to the site, in which case the transportation work is difficult. . Therefore, the applicant of the present application has proposed a filtration device that can be assembled on site and easy to handle (Japanese Patent Application No. 2004-293219). The filtration device includes a container opened upward, a water-collecting material having a water permeability made of a cylindrical woven fabric housed in the container, and a sand layer filled in the container above the water collecting material. ing. In this filtering device, when water to be treated such as waste water is introduced into the container from above, the water to be treated flows down while being filtered by the sand layer, and further, a water-permeable water collecting material is provided below the sand layer. It flows in and is discharged out of the container through the water collecting material.

JP-A-5-154309

  By the way, in the filtration apparatus provided with the water-permeable water collecting material as described above, the water collecting material becomes clogged as the water to be treated is filtered, and the water collecting function of the water collecting material gradually increases. It goes down. When the water collecting function is lowered, the substantial filtration capacity is lowered, so it is necessary to eliminate the clogging of the water collecting material. As one of the methods, air is supplied from one end of the water collecting material. Can be considered, and a method of jetting air from the inside of the water collecting material to the outside (back washing) can be considered. However, just sending air directly from one end of the water collection material to the clogged portion at the other end is difficult to supply enough high-pressure air. It is difficult to resolve it over the entire length.

  An object of the present invention is to provide a sand filtration device that can reliably eliminate clogging of a water collecting material over its entire length.

Means for Solving the Problems and Effects of the Invention

  The sand filtration device of the first invention is formed of a container into which water to be treated is introduced from above, and a cylindrical woven fabric having a self-retaining property using a yarn having a bending resilience for at least a part of the weft. A water collecting material housed in the container, a first filtration layer composed of a sand layer filled above the water collecting material in the container, and the entire length of the water collecting material. And a fluid supply pipe inserted therethrough.

  When water to be treated such as waste water to be filtered is introduced into the container from above, the water to be treated flows down while being filtered by the first filtration layer made of a sand layer. And the water filtered by the 1st filtration layer flows into the water collection material located under this 1st filtration layer, and is discharged | emitted outside through a water collection material. By the way, as the water to be treated is filtered, the water collecting material is clogged, and the water collecting function of the water collecting material is gradually lowered. However, in the sand filtration device according to the first aspect of the present invention, the fluid supply pipe is inserted through the entire length of the water collecting material. Therefore, since a fluid having a high pressure can be supplied to the depth of the water collecting material through the fluid supply pipe, clogging of the water collecting material can be surely eliminated.

  According to a second aspect of the present invention, there is provided the sand filtration device according to the first aspect, wherein the fluid supply pipe is formed with a plurality of ejection holes arranged at appropriate intervals in the longitudinal direction. is there. Accordingly, the fluid is ejected from the plurality of ejection holes into the water collecting material, and the fluid is supplied almost uniformly in the longitudinal direction inside the water collecting material, so that the fluid is not partially biased. Therefore, clogging can be reliably eliminated over the entire length of the water collecting material.

  The sand filtration device according to a third aspect is the sand filter according to the second aspect, wherein the fluid supply pipe is composed of a plurality of tube-like members respectively disposed in the water collecting material. The portions where the ejection holes are formed are arranged so as not to be adjacent to each other in the length direction. When the length of the water collecting material is long, even if a high pressure fluid is supplied from one end of the fluid supply pipe in the water collecting material, the fluid pressure at the other end of the water collecting material is considerably low. The effect of backwashing is reduced. However, in the third aspect of the invention, a plurality of tubular members are inserted into the water collecting material, and the portions in which the ejection holes of the plurality of tubular members are formed are mutually in the length direction. It is arranged so as not to be adjacent to each other. In this way, since the ejection holes are not formed over the entire length in the plurality of tubular members, a high fluid pressure can be applied over the entire length from one end portion to the other end portion of the water collecting material. .

  In the sand filtration device according to a fourth aspect of the present invention, in any one of the first to third aspects, a second filtration layer different from the first filtration layer is provided above the first filtration layer. It is characterized by this. This 2nd filtration layer is for catching the comparatively big solid substance contained in to-be-processed water. Therefore, since the solid matter in the water to be treated is collected to some extent by the second filtration layer before the water to be treated is filtered by the first filtration layer made of the sand layer, the filtration performance of the first filtration layer is hardly lowered, The frequency of maintenance work such as exchanging the first filtration layer can be reduced.

  The sand filtration device according to a fifth aspect of the present invention is the sand filtration apparatus according to any one of the first to fourth aspects, wherein the fluid supplied from the fluid supply pipe into the water collecting material is ejected to the first filtration layer. The first filtration layer is configured to be able to stir. As the water to be treated is filtered, deposits such as sludge accumulate on the surface of the first filtration layer, and the filtration performance of the first filtration layer decreases. However, in the fifth aspect of the invention, the fluid supplied from the fluid supply pipe into the water collecting material in order to eliminate clogging of the water collecting material further blows up the first filtration layer above the water collecting material. And stirring to destroy the layer of the deposit formed on the surface of the first filtration layer, the filtration performance of the first filtration layer is recovered. That is, it is possible to extend the usage period of the first filtration layer and reduce the frequency of maintenance work such as replacement of the first filtration layer.

Embodiments of the present invention will be described with reference to FIGS. This embodiment is an example in which the present invention is applied to a sand filtration device used when filtering wastewater generated in excavation work for tunnels and pile holes, dredging work for mud in rivers and lakes, and the like.
As shown in FIGS. 1 to 4, the sand filtration device 1 of the present embodiment includes a container 2 opened upward, a water collecting material 3 stored in the container 2, and a water collecting material 3 in the container 2. And a sand layer 4 filled on the upper side. In FIG. 2, the left side portion in the container 2 shows a cross section in a state where the sand layer 4 is not filled, while the right side portion in the container 2 shows a cross section in a state where the sand layer 4 is filled. . FIG. 3 shows a plan view of the sand filtering device 1 in a state where the sand layer 4 is not filled.

  The container 2 is formed in a box shape opened upward such as a material made of a material having high strength and durability, such as FRP (fiber reinforced plastic) or stainless steel, or a simple water tank made of a resin sheet. As shown in FIG. 2, it is placed on a flat base 6. And from the upper part of this container 2, the waste water which is the to-be-processed water filtered is supplied.

  As shown in FIG. 2 to FIG. 4, a hose-shaped water collecting material 3 having water permeability is accommodated in a lower portion in the container 2 in an appropriately bent state. As shown in FIG. 5, the water collecting material 3 is composed of a tubular woven fabric 10 woven in an annular shape using warp yarns 11 and weft yarns 12. Here, at least a part of the weft 12 is made of a yarn having bending resilience, and the tubular woven fabric 10 constituting the water collecting material 3 has a self-retaining property. And it is possible to change the water permeability of the water collecting material 3 according to the kind of waste water, etc. by adjusting the weave structure of the water collecting material 3 suitably. As an example of such a water collecting material 3, it is woven in an annular shape with a warp 11 made of polyester fiber having a thickness of 8350 dtex and a SUS wire having a thickness of φ1.8 mm, and a weft 12 having a density of 30 P / 10 cm. The cylindrical woven fabric 10 having a diameter of 110 mm can be used. As shown in FIG. 3, one end of the water collecting material 3 is located in the container 2 in a state of being closed by a metal fitting 18. On the other hand, the other end of the water collecting material 3 is connected to a drain pipe 5 that extends from the side wall of the container 2 to the outside.

  As shown in FIGS. 1, 2, and 4, in the container 2, sand is entirely deposited on the upper side of the water collecting material 3 to form a sand layer 4 (first filtration layer). Various types of sand can be used as the sand of the sand layer 4 depending on the turbidity of the wastewater and the type of solids contained in the wastewater. For example, river sand for concrete aggregate can be used. The height H of the sand layer 4 is set to about three times (about 330 mm) the diameter of the water collecting material 3 (for example, 110 mm).

  On the sand layer 4, a metal sieve 13 formed in a mesh shape of about 3 mm is disposed. Further, the sieve 13 is considerably thinner than the sand layer 4 (for example, a thickness of several centimeters). The sand layer 7 is provided. The sieve 13 is for removing a surface deposited mud film (mud filter) generated by waste water introduced into the container 2. The sand layer 7 is for accelerating the agglomeration and adhesion of the surface deposited mud film on the sieve 13. That is, the sieve 13 and the sand layer 7 remove some solid matter in the waste water before the waste water penetrates into the sand layer 4, so that the solid matter is difficult to enter the sand layer 4 and the filtration performance of the sand layer 4 is reduced. It is difficult to do. The sieve 13 and the sand layer 7 correspond to the second filtration layer of the present invention.

  As shown in FIGS. 1 to 3, a drainage pipe 5 connected to the water collecting material 3 is attached to the container 2. The drain pipe 5 is provided with a valve 14 for opening and closing. In a state where the valve 14 is opened, the water collected by the water collecting material 3 after being filtered by the sand layer 4 is discharged through the drain pipe 5 to the drainage container 20 installed outside the container 2.

  As shown in FIGS. 2 and 3, a branching tee 15 is provided in the middle of the drainage pipe 5 between the container 2 and the valve 14. A resin-made flexible air tube 16 (fluid supply pipe) is inserted through the pipe. The air tube 16 is connected to an air pump 17. Further, the air tube 16 has a diameter (for example, 10 mm) sufficiently smaller than the diameter (for example, 110 mm) of the water collecting material 3, and as shown in FIG. The water collecting material 3 is inserted through the entire length (for example, 6 m). Furthermore, as shown in FIG. 2, the portion inserted into the water collecting material 3 of the air tube 16 has a small diameter (for example, about 2 mm) with an appropriate interval (for example, 100 mm) in the length direction. A plurality of ejection holes 16a are formed.

  Accordingly, when the water collecting material 3 is clogged and the water collecting function is lowered as the filtration process is performed, when air is sent from the air pump 17 to the air tube 16, the air is collected into the water collecting material 3. Inside, it ejects from the several ejection hole 16a of the air tube 16, and also it ejects from the inside of the water collection material 3 to the external sand layer 4. FIG. And the water-collecting material 3 is reverse-washed with the air to eject, and the clogging is eliminated. In addition, when the air supplied into the water collection material 3 from the air tube 16 spouts to the sand layer 4, the sand layer 4 can be blown up and stirred by this air.

Next, the operation of the sand filtration device 1 will be described.
First, when the waste water is introduced from above the container 2 after opening the valve 14 provided in the drain pipe 5, the waste water flows downward while being filtered by the sand layer 4. Furthermore, the filtered water flows into the water-permeable water collecting material 3 located below the sand layer 4 and is discharged from the water collecting material 3 to the outside of the container 2 through the drain pipe 5. In this embodiment, as shown in FIGS. 1, 2, and 4, a mesh-like sieve 13 is disposed on the sand layer 4, and a thin sand layer 7 is further provided thereon. Therefore, before the wastewater penetrates into the sand layer 4, the solid matter contained in the wastewater is removed to some extent by the sieve 13 and the sand layer 7.

  Here, as the wastewater is filtered, the water collecting material 3 is gradually clogged, so that the water collecting function is lowered. Therefore, when the water collecting function of the water collecting material 3 has deteriorated, the valve 14 is closed and then the air pump 17 is activated to supply high pressure (for example, about 0.3 MPa) air through the air tube 16. Send to 3. At this time, in the water collecting material 3, air is ejected from the plurality of ejection holes 16 a of the air tube 16, and further, this air is ejected from the inside of the water collecting material 3 to the outside. Then, since the water collecting material 3 is back-washed with air and the clogging is eliminated, the water collecting function of the water collecting material 3 is restored. Further, depending on the height of the sand layer 4 and the type of sand, the air formed on the surface of the sand layer 4 is agitated by blowing up and stirring the sand layer 4 on the upper side of the water collector 3 with the air jetted from the water collector 3 to the sand layer 4. It is also possible to destroy layers of things.

According to the sand filtration apparatus 1 demonstrated above, the following effects are acquired.
Since the air tube 16 is inserted through the entire length of the water collecting material 3, when air is supplied from the air pump 17 through the air tube 16 into the water collecting material 3 and backwashing is performed, the air collecting is performed. High-pressure air can be reliably supplied to the depth of the water material 3. The air tube 16 is formed with a plurality of ejection holes 16a arranged at appropriate intervals in the longitudinal direction, so that air is supplied substantially uniformly in the longitudinal direction in the water collecting material 3. Therefore, the air is not partially biased and supplied, and clogging can be reliably eliminated over the entire length of the water collecting material 3. Furthermore, when the sand layer 4 on the upper side of the water collection material 3 is blown up and stirred by the air jetted from the water collection material 3 to the sand layer 4 during backwashing, the filtration performance of the sand layer 4 can be recovered. Therefore, the use period of the sand layer 4 can be extended and the frequency of maintenance work such as replacement can be reduced.

  Since the sieve 13 is disposed on the sand layer 4 and the thin sand layer 7 is further provided thereon, the solids contained in the waste water by the sieve 13 and the sand layer 7 before the waste water penetrates into the sand layer 4. You can collect things to some extent. And the solid substance deposited on the surface of the sand layer 7 can be easily removed from the container 2 together with the sieve 13 and the sand layer 7, and the frequency of maintenance work such as replacement of the sand layer 4 can be further reduced.

  In addition, the sand filtration apparatus 1 of this embodiment is intended to remove suspended substances such as sand contained in wastewater by the sand layer 4, and is mainly intended to remove harmful substances dissolved in the wastewater. is not. Therefore, the sand layer 4 is not limited to a specific type. However, as described above, in order to simultaneously stir the sand layer 4 with the air ejected from the water collecting material 3 during the reverse cleaning for eliminating the clogging of the water collecting material 3, the sand layer 4 is compared with It is preferable to use sand having a small target particle size and to set the height H (see FIG. 2) of the sand layer 4 according to this sand.

Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.
1] If the solid matter in the waste water cannot be sufficiently removed by performing filtration once with the sand layer 4 such as when the turbidity of the waste water is quite high, the water discharged into the drainage container 20 May be introduced again into the container 2 using a circulation pump or the like, and filtration may be repeated many times.

  2] When the water collecting material 3 is long and only one air tube 16 is inserted into the water collecting material 3 as in the above embodiment, high pressure air is supplied from one end of the air tube 16. However, the pressure of the air supplied at the other end portion (tip portion) of the water collecting material 3 becomes considerably low, and the effect of back washing at the tip portion is reduced. Therefore, as shown in FIG. 6, a plurality of (for example, three) air tubes 30, 31, and 32 (tubular members) are inserted into the water collecting material 3, and the air tubes 30 to 32 are passed through these air tubes. Each of the water collecting members 3 may be configured to be supplied with air. Here, it is preferable that the portions where the ejection holes of the plurality of air tubes 30 to 32 are formed are arranged so as not to be adjacent to each other in the length direction. For example, as shown in FIG. 6, the air tubes 30, 31, and 32 are bundled in the water collecting material 3 in a state of being shifted in the length direction so that the tip portions 30 a, 31 a, and 32 a are not adjacent to each other. A plurality of ejection holes 30b, 31b, 32b may be formed in the tip portions 30a, 31a, 32a of the air tubes 30, 31, 32, respectively. According to this configuration, since the ejection holes 30b to 32b are not provided over the entire length of the air tubes 30 to 32, the pressure sufficiently acts to the tips of the air tubes 30 to 32, and the water collecting material 3 The effect of backwashing can be further enhanced by applying a high air pressure over the entire length from one end to the other end.

  3] As shown in FIG. 7, a sheet material 21 having water permeability may be embedded in the sand layer 4. In this case, deposits such as sludge accumulated on the surface of the sand layer 4 can be taken out from the container 2 together with the sheet material 21 and the sand layer 4a on the upper side of the sheet material 21 and disposed of. The sand layer 4 can be easily replaced. Further, in addition to the sheet material 21, a bag 22 having water permeability disposed along the inner surface of the container 2 may be embedded in the sand layer 4. In this case, the deposit deposited on the surface of the sand layer 4 can be taken out of the container 2 together with the bag body 22 and the sand layer 4a inside the bag body 22 and disposed of. Exchange can be performed more easily. If the deposit contains a large amount of moisture, the bag 22 taken out from the container 2 may be dried in the sun as it is, and left until the amount of moisture in the deposit is sufficiently reduced, and dehydrated. No special work is required.

  4] In the above embodiment, one end (the end opposite to the drain pipe 5) of the water collecting material is closed and located in the container 2, but this end also communicates with the outside of the container 2. The air tube 16 may be inserted from this end. Alternatively, the air tube 16 may be inserted so as to protrude from both ends of the water collecting material. In this case, it is possible to drain water from one or both ends of the water collecting material to the outside of the container 2 and to feed back cleaning air from the other end or both ends of the water collecting material through the air tube 16.

  5] The shape and structure of the water collecting material are not limited to the water collecting material 3 of the above embodiment. For example, as shown in FIG. 8, a water collecting material 3 </ b> A wound in a coil shape, having one end 3 a connected to a drain pipe 5 (see FIG. 1) and the other end 3 b closed by a metal fitting 24. Can be used. Further, as shown in FIG. 9, one end 3 a of the plurality of water collecting members 3 </ b> A of FIG. Alternatively, as shown in FIG. 10, a plurality of water collecting members 3B extend in one direction, and both ends of the plurality of water collecting members 3B are connected by two pipes 26 and 27, respectively. May be used. In this case, the fluid supply pipe for supplying air into the water collecting material 3B may be flexible like the air tube 16 of the above embodiment, but may be rigid. .

  6] In the above-described embodiment, the sieve 13 is disposed on the sand layer 4, and the thin sand layer 7 is further disposed on the sieve 13, but the solid matter contained in the wastewater is silt or clay. In the case of a sticky material such as a lot of red soil, it is possible to capture the solid matter with the sieve 13 alone. Therefore, when treating such waste water, only the sieve 13 may be provided on the sand layer 4 and the sand layer 7 thereon may be omitted. In this case, the sieve 13 becomes the second filtration layer.

  The sieve 13 is not limited to a metal mesh, and for example, a flexible mesh-like surface material made of synthetic fiber and synthetic resin such as geogrid may be used. Since such a flexible planar material is more in line with the unevenness of the sand layer surface than the metal mesh, when filtering wastewater containing a large amount of clay and silt having a particle diameter of 1 mm or less, as described above, Can capture solids well.

  7] In the above embodiment, the water collecting material 3 is back-washed by supplying air into the water collecting material 3 through the air tube 16, but by feeding liquid such as water into the water collecting material 3. The water collecting material may be back-washed.

  8] The above embodiment is an example in which the present invention is applied when filtering wastewater generated at a construction site, but the treated water that can be filtered by the sand filtration device of the present invention is limited to such wastewater. It is not a thing. For example, the present invention can also be applied to the case where seawater taken in a seawater desalination apparatus is filtered.

1 is a schematic perspective view of a sand filtration device according to an embodiment of the present invention. It is a longitudinal cross-sectional view of a sand filtration apparatus. It is a top view of a sand filtration apparatus. It is the IV-IV sectional view taken on the line of FIG. It is a partially cutaway perspective view of the tubular woven fabric constituting the water collecting material. It is a top view of the air tube of a change form. It is sectional drawing equivalent to FIG. 4 of another modification. It is a perspective view of the water collecting material of another modification. It is a perspective view which shows the structure by which the some water collecting material of FIG. 8 was mutually connected by the pipe. It is a perspective view of the water collecting material of another modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sand filtration apparatus 2 Container 3, 3A, 3B Catch material 4 Sand layer 7 Sand layer 10 Cylindrical woven fabric 13 Sieve 16 Air tube 16a Air jet hole 30,31,32 Air tube 30b, 31b, 32b Air jet hole

Claims (5)

A container into which treated water is introduced from above;
A water collecting material formed of a cylindrical woven fabric having a self-retaining property using a yarn having bend resilience in at least a part of the weft, and housed in the container;
In the container, a first filtration layer consisting of a sand layer filled on the upper side of the water collecting material,
A fluid supply pipe inserted through the entire length of the water collecting material;
A sand filtration device comprising:   The sand filtration device according to claim 1, wherein the fluid supply pipe is formed with a plurality of ejection holes arranged at appropriate intervals in the longitudinal direction. The fluid supply pipe is composed of a plurality of tubular members respectively disposed in the water collecting material,
The sand filtration device according to claim 2, wherein portions of the plurality of tubular members in which the ejection holes are formed are arranged so as not to be adjacent to each other in the length direction.   The sand filtration device according to any one of claims 1 to 3, wherein a second filtration layer different from the first filtration layer is provided on the upper side of the first filtration layer. The fluid supplied into the water collecting material from the fluid supply pipe is jetted to the first filtration layer, and the first filtration layer is configured to be capable of being stirred. The sand filtration apparatus according to any one of the above.

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