JP6661047B1 - Method for reforming slow filtration pond, reforming system for slow filtration pond and scraper device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of reforming by simplifying the device so that sand can be left as much as possible to scrape away unwanted materials and facilitate discharging of unwanted materials to facilitate disposal of unwanted materials. Try. SOLUTION: The slow filtration basin 1 having a filter layer 2 and a side wall 3 for accumulating water and filtering the water by the filter layer 2 to purify the water is reformed, and an unnecessary substance F on the surface of the filter layer 2 is modified. A scraper device S including a scraper 10 for scraping off the water, a water supply unit 11 for supplying water to the filtration basin 1, and a drain port 12 provided at an upper portion of the filtration basin 1 for discharging inflowing water, The waste material F scraped off by the scraper 10 of the apparatus S was floated in the accumulated water so as to be discharged together with the water discharged from the drainage port 12, and the scraper 10 had an outer surface that abuts the surface of the filtration layer 2. It is composed of a mesh-shaped expanded metal 16. [Selection diagram] Fig. 1

Description

  The present invention relates to a method and a system for reforming a slow filtration pond having a filtration layer for obtaining water used for water supply and the like, and more particularly, to a filtration layer in a state where water is stored in the slow filtration pond. TECHNICAL FIELD The present invention relates to a method for reforming a slow filtration pond and a reforming system for a slow filtration pond for shaving and reforming a surface of a slow filtration tank. Also, the present invention relates to a method for reforming the slow filtration pond and a scraper device which can be effectively used for the reforming system for the slow filtration pond.

  Generally, slow filtration ponds used in waterworks and the like have a filtration layer and side walls that are erected around the filtration layer, collect water, and filter the water through the filtration layer to purify water. In the filtration layer, suspended substances in the water are removed by filtration using filter sand, and dissolved components and odor components in the water are removed by the biochemical action of the biofilm that has propagated on the surface of the filtration layer. High-quality filtered water can be obtained.

  In this slow filtration pond, biofilms and the like accumulate on the surface of the filtration layer over time, so that unnecessary substances increase and water gradually becomes difficult to pass. Water is drained from the filter ponds, and the sand on the surface of the filter layer is scraped to remove unnecessary substances, and reformed by supplying new sand. Soil is washed and reused. However, in this reforming, since water is drained one by one and then the contaminated sand is removed, there is a problem that the operation is complicated and the reforming efficiency is low. There has been proposed a reforming method of reforming the filtration layer by discharging unnecessary substances in the filtration layer in a state where water is retained without draining water from the pond.

  Conventionally, a method for reforming a slow filtration pond that discharges unnecessary substances from a filtration layer while storing this kind of water is disclosed in, for example, JP-A-58-17804 (Patent Document 1). Technology is known. In this method, a float that can be moved by wire from the outside of the filtration pond is floated on the surface of the water, and a sand scraper that can move up and down in water is installed on the float, and this sand scraper contaminates unnecessary substances on the surface of the filtration layer. The scraped sand is scraped together with the sand, and the scraped sand is sucked by a suction hose by a suction pump mounted on the float and discharged to the outside of the filtration pond by a discharge hose. The sand scraper includes an auger driven by an electric motor, and a cover that covers one side of the auger and has a lower edge formed as a scraper to scrape off unnecessary materials.

JP-A-58-17804

  By the way, in the conventional method for reforming a slow filtration pond, unnecessary substances formed on the surface of the filtration layer can be discharged in a state where water is stored without draining water from the slow filtration pond. Although the workability is improved, there is a problem that the float is provided with a motor-driven sand scraper and also equipped with a suction hose, a suction pump, and a discharge hose, which complicates the apparatus. In addition, since unnecessary substances are discharged together with the contaminated sand, there is a problem in that since a considerable amount of sand is contained, transportation and processing after discharge by a discharge hose are complicated, and processing efficiency is poor. Furthermore, since the sand on the surface of the filtration layer is also removed, organisms propagated in the sand are taken too much, and there is a problem that it takes time to recover until an effective biofilm is formed again.

  The present invention has been made in view of such a problem, and makes it possible to simplify the apparatus, leave unremoved sand as much as possible so that unnecessary materials can be scraped off, and facilitate the discharge of unnecessary materials, and It is an object of the present invention to provide a method for reforming a slow filtration pond and a reforming system for a slow filtration pond, which facilitate the treatment of unnecessary substances and improve the reforming efficiency. It is another object of the present invention to provide a scraper device capable of reliably removing unnecessary substances with a simple structure effective for the method for reforming the slow filtration pond and the reforming system for the slow filtration pond.

In order to achieve such an object, the method for reforming a slow filtration pond according to the present invention has a filtration layer and a side wall that stands upright surrounding the filtration layer, stores water, and collects water through the filtration layer. In a method of reforming a slow filtration pond, the unnecessary substance formed on the surface of the filtration layer of the slow filtration pond for filtering and purifying water is discharged in a state in which water is stored to reform the filtration layer.
Using a scraper to scrape off unnecessary substances on the surface of the filtration layer, forming the scraper in a mesh plate shape having an outer surface in contact with the surface of the filtration layer, and applying the scraper to the outer surface of the filtration layer. It is moved in contact with it, scraping off unnecessary substances on the surface of the filter layer and suspending it in the accumulated water, supplying water to the filter pond and draining from the drain port, and discharging unnecessary substances together with the drained water. The configuration is such that

  Thereby, when reforming the slow filtration pond, the scraper is moved with its outer surface in contact with the surface of the filtration layer. As a result, unnecessary substances on the surface of the filtration layer are scraped off and floated in the accumulated water. In this case, since the scraper is formed in a mesh shape, a large number of members forming the mesh are arranged in the moving direction, and therefore, the surface of the filtration layer is repeatedly scraped. Unnecessary items can be reliably removed. Further, since the scraped-off unnecessary material passes through the mesh of the scraper, it can be easily floated in water as compared with a case where the scraped-off unnecessary material is simply scraped off with a plate. Further, in this case, some of the contaminated sand on the surface of the filtration layer may be scraped off. However, since the sand is heavy, it rises temporarily but sinks down, so that unnecessary substances to be removed can be floated. Unnecessary substances are scraped off from the surface of the filtration layer, so that the filtration function is restored. In addition, the sand that has been scraped off to some extent remains settled, and some biofilm remains, so effective biofilm recovery is quick and the biochemical effects of biofilm can be maintained. it can.

  Then, since water is supplied to the filtration pond and drained from the drain port, unnecessary substances are discharged together with the drained water. Therefore, unnecessary substances can be easily discharged, and the processing of sand is not required. Therefore, the processing of the unnecessary substances after the discharge is extremely easy, and the reforming efficiency can be improved accordingly. As described above, since the filtration layer can be reformed only by moving the mesh-shaped scraper, the apparatus can be simplified.

  If necessary, a rope that pulls and moves the scraper is engaged with the scraper, and the scraper is moved by pulling the rope on the side wall of the filtration pond. The traction of the cord can be performed using a machine such as a winch, or can be performed manually. Since the cord is used, the scraper can be easily moved. Further, since the cord is towed on the side wall, the operation is also facilitated. In this case, depending on the pulling force of the cord, the scraper tends to rise, but the scraper is moved with its outer surface in contact with the surface of the filtration layer so as not to rise as much as possible. If the front end of the scraper in the towing direction rises or comes into contact with the ground, the scraper may move up and down slightly.

In addition, if necessary, the filtration pond is configured to include a rectangular filtration layer as viewed from a plane, and four side walls erected around the filtration layer,
One of the pair of side walls opposed to each other in one direction is engaged with one of the side walls of the scraper, and the other of the two ropes is connected to the other side wall. The forward movement to move the scraper by contacting the outer side surface thereof to the surface of the filtration layer by the body, and the outer side surface of the scraper is brought into contact with the surface of the filtration layer by the other cord from the other side wall. Moving back and moving the scraper, the one cord body and the other cord body in the other direction orthogonal to the one direction to change the contact position of the outer surface of the scraper with the surface of the filtration layer. The scraper is moved to scrape off unnecessary objects. Thereby, while sequentially changing the positions of the scraper, the one-sided body and the other-sided body in the other direction between the side walls facing each other in one direction, the one-sided body and the other-sided body are alternately pulled to reciprocate the scraper. Thus, the surface of the filtration layer can be uniformly scraped off, and thus the filtration layer can be reformed with a simple operation, so that the reforming efficiency can be improved.

  Further, if necessary, the scraper is made of a metal expanded metal in which openings are regularly arranged and formed by strands having a rectangular cross section by stretching. The expanded metal is formed by arranging, on a metal plate, a row of cuts having predetermined widths at predetermined pitches P such that the breaks between adjacent cuts have a (1/2) P phase shift. It is a well-known method in which a plate is stretched in a direction perpendicular to the direction of the cut to form an opening which is a mesh at the cut. The opening is formed in a flat diamond shape, a flat hexagonal shape, a regular square shape, or the like. Since this expanded metal is relatively heavy, the outer surface can be easily brought into contact with the surface of the filtration layer, and the members constituting the openings, which are meshes, are strands having a rectangular cross section. The shaving can be performed, and thus the shaving can be reliably performed.

  Furthermore, if necessary, the scraper is pulled in a direction along the expanding direction of the expanded metal. Since the continuity of the edge of the strand in the direction perpendicular to the pulling direction is good, it is possible to reliably remove unnecessary objects. In particular, in the case where the opening which is the mesh of the scraper is flat, since the stretching direction is the shorter direction of the opening, the strands in the longitudinal direction of the opening will mainly scrape the surface of the filtration layer, Therefore, since the length of the strand in the longitudinal direction is larger than that in the lateral direction, the unnecessary material can be reliably removed.

  Further, if necessary, in a cross section cut along the direction of extension of the expanded metal of the scraper, the angle of inclination of the surface of the strand with respect to the outer surface line forming the outer surface of the scraper on the acute angle side is θ. In this case, the scraper is configured such that the acute angle side of the inclination angle θ of the strand is oriented in the traction direction. Since the acute angle side faces the traction direction, the resistance of the edge of the strand to bite into the surface of the filtration layer becomes smaller than that of the obtuse angle side, so that the movement can be performed smoothly. In particular, when the towing is performed manually, the load is reduced, which is preferable.

  Further, if necessary, when switching from the forward movement to the backward movement, or when switching from the backward movement to the forward movement, the scraper with respect to the rope body such that the acute angle side of the inclination angle θ of the scraper faces the towing direction. Is inverted. Reversal includes direction reversal that rotates around the axis perpendicular to the outer surface of the scraper, and front and back reversal that rotates the scraper about the axis along the direction of expansion of the expanded metal. Can be selected accordingly. This makes it possible to turn the scraper at an acute angle of the inclination angle θ in the towing direction only by changing the direction or the front and back of the scraper without changing the direction of the rope body, so that the operation can be easily performed.

In addition, a reforming system for a slow filtration pond according to the present invention for achieving the above object has a filtration layer and side walls that are erected around the filtration layer, collects water, and collects water through the filtration layer. In a reforming system of a slow filtration pond that reforms the filtration layer by discharging unnecessary substances formed on the surface of the filtration layer of the slow filtration pond that filters and purifies the water, in a state where water is stored,
A scraper device provided with a scraper for scraping off unnecessary substances on the surface of the filtration layer, a water supply unit for supplying water to the filtration pond, and an opening provided at an upper part of the filtration pond so that water in the filtration pond flows in. A drain port for discharging the inflowing water, and a slow speed in which unnecessary substances scraped off by the scraper of the scraper device are floated in accumulated water, and the unnecessary substances are discharged together with the water discharged from the drain port. A filter pond reforming system,
The scraper of the scraper device is formed in a net plate shape having an outer surface in contact with the surface of the filtration layer.

  Thereby, when reforming the slow filtration pond, the scraper of the scraper device is moved with its outer surface in contact with the surface of the filtration layer. As a result, unnecessary substances on the surface of the filtration layer are scraped off and floated in the accumulated water. In this case, since the scraper is formed in a mesh shape, a large number of members forming the mesh are arranged in the moving direction, and therefore, the surface of the filtration layer is repeatedly scraped. Unnecessary items can be reliably removed. Further, since the scraped-off unnecessary material passes through the mesh of the scraper, it can be easily floated in water as compared with a case where the scraped-off unnecessary material is simply scraped off with a plate. Further, in this case, some of the contaminated sand on the surface of the filtration layer may be scraped off. However, since the sand is heavy, it rises temporarily but sinks down, so that unnecessary substances to be removed can be floated. Unnecessary substances are scraped off from the surface of the filtration layer, so that the filtration function is restored. In addition, the sand that has been scraped off to some extent remains settled, and some biofilm remains, so effective biofilm recovery is quick and the biochemical effects of biofilm can be maintained. it can.

  Then, since water is supplied to the filtration pond from the water supply unit and drained from the drain port, unnecessary substances are discharged together with the drained water. Therefore, unnecessary substances can be easily discharged, and the processing of sand is not required. Therefore, the processing of the unnecessary substances after the discharge is extremely easy, and the reforming efficiency can be improved accordingly. As described above, since the filtration layer can be reformed only by moving the net-shaped scraper of the scraper device, the entire system can be simplified.

  And if necessary, the scraper device is provided with a cord attached to the scraper for pulling and moving the scraper on the side wall of the filtration pond. The traction of the cord can be performed using a machine such as a winch, or can be performed manually. Since the cord is used, the scraper can be easily moved. Further, since the cord is towed on the side wall, the operation is also facilitated. In this case, depending on the pulling force of the cord, the scraper tends to rise, but the scraper is moved with its outer surface in contact with the surface of the filtration layer so as not to rise as much as possible. If the front end of the scraper in the towing direction rises or comes into contact with the ground, the scraper may move up and down slightly.

  If necessary, the scraper device is provided with a pulling mechanism for pulling the rope. Since the towing is performed by the towing mechanism, the towing can be easily performed.

  Further, if necessary, the scraper is made of a metal expanded metal in which openings are regularly arranged and formed by strands having a rectangular cross section by stretching. The expanded metal is formed by arranging, on a metal plate, a row of cuts having predetermined widths at predetermined pitches P such that the breaks between adjacent cuts have a (1/2) P phase shift. It is a well-known method in which a plate is stretched in a direction perpendicular to the direction of the cut to form an opening which is a mesh at the cut. The opening is formed in a flat diamond shape, a flat hexagonal shape, a regular square shape, or the like. Since this expanded metal is relatively heavy, the outer surface can be easily brought into contact with the surface of the filtration layer, and the members constituting the openings, which are meshes, are strands having a rectangular cross section. The shaving can be performed, and thus the shaving can be reliably performed.

  Furthermore, if necessary, the scraper device further includes a rope that is engaged with the scraper and that pulls and moves the scraper on a side wall of the filtration pond. Are attached to the scraper so as to extend in the direction in which the expanded metal extends. Since the continuity of the edge of the strand in the direction perpendicular to the pulling direction is good, it is possible to reliably remove unnecessary objects. In particular, in the case where the opening which is the mesh of the scraper is flat, since the stretching direction is the shorter direction of the opening, the strands in the longitudinal direction of the opening will mainly scrape the surface of the filtration layer, Therefore, since the length of the strand in the longitudinal direction is larger than that in the lateral direction, the unnecessary material can be reliably removed.

  In this case, in a cross section obtained by cutting the rope body along the expanding direction of the expanded metal of the scraper, an inclination angle of an acute angle side of a surface of the strand with respect to an outer surface line forming an outer surface of the scraper. When θ is θ, it is effective that the scraper can be engaged so that the acute angle side of the inclination angle θ of the strand faces the traction direction. Since the acute angle side of the strand is oriented in the pulling direction, the resistance at which the edge of the strand bites into the surface of the filtration layer is smaller than that of the obtuse angle side, so that the movement can be performed smoothly. In particular, when the towing is performed manually, the load is reduced, which is preferable.

In addition, if necessary, the filtration pond is configured to include a rectangular filtration layer as viewed from a plane, and four side walls erected around the filtration layer,
The above-mentioned cord body includes one cord body reaching one side wall of a pair of side walls facing each other in one direction, and another cord body reaching the other side wall of the pair of side walls facing each other in one direction. Configure
The scraper device is provided with a reversing mechanism that enables the scraper to be reversed so that the acute angle side of the inclination angle θ of the strand is oriented in the pulling direction during the towing by the one rope and the towing by the other rope, respectively. And The reversal includes a direction reversal that rotates around an axis perpendicular to the outer surface of the scraper, and a front and back reversal that rotates the scraper about an axis that extends along the expanded direction of the expanded metal. The scraper is configured to be reversible in direction or reversible from front to back depending on the manner of wearing.

  Thereby, the scraper is pulled by one cord, and the scraper is pulled by the other cord to reciprocate the scraper to scrape the surface of the filtration layer. In this case, the position of the scraper, the one cord body and the other cord body is moved in the other direction orthogonal to the one direction, and the scraper is moved in a different position to change the contact position of the outer surface of the scraper with the surface of the filtration layer. While moving forward and backward. In this case, the reversing mechanism allows the scraper to be inverted so that the acute angle side of the inclination angle θ of the strand faces the pulling direction, that is, only by changing the direction and the front and back of the scraper without changing the direction of the rope body, The acute angle side of the inclination angle θ of the scraper can be directed to the towing direction, and the operation can be performed easily. Therefore, the surface of the filtration layer can be evenly removed while the scraper is smoothly moved, so that the working efficiency can be improved.

  In this case, the scraper device includes a pulling mechanism for pulling the rope body, and the pulling mechanism is provided on the one side wall, pulls the one rope body from the one side wall, and pulls the scraper on the outer surface. A winch for making a forward movement to be brought into contact with the surface of the filtration layer, and a winch provided on the other side wall, and pulling the other cable body from the other side wall to pull the scraper on its outer surface to the surface of the filtration layer; It is effective to provide a winch on the other hand to perform a reciprocating movement in which the abutting member is moved in contact with the other. In this case, the traction force of the winch is set so that the traction side of the scraper is not raised as much as possible by the traction. If the front end of the scraper in the towing direction rises or comes into contact with the ground, the scraper may move up and down slightly. Since the scraper can move while its outer surface is in contact with the surface of the filtration layer, the scraping efficiency is extremely improved. Thereby, the scraper is moved from one side wall to the other by moving the scraper from one side wall to the surface of the filtration layer by the one winch, and the other winch is used to move the scraper from the other side wall to the other rope body. Since the backward movement is performed in which the outer side surface is brought into contact with the surface of the filtration layer and moved, the traction becomes easy, the operability is improved, and the workability can be greatly improved.

  Further, in this case, the scraper device is provided on the one side wall, the one rail supporting the one winch so as to be movable along the other direction orthogonal to the one direction, and the scraper device is provided on the other side wall. And a second rail for movably supporting the winch along the other direction perpendicular to the one direction, and moving the positions of the scraper, the one rope body and the other rope body in the other direction perpendicular to the one direction. It is effective to adopt a configuration in which the position changing movement of changing the contact position of the outer surface of the scraper with the surface of the filtration layer is possible. Thereby, the position change movement of the one winch and the other winch in the other direction becomes easy, and accordingly, the operability can be improved and the workability can be greatly improved.

  A scraper device for achieving the above object has a filtration layer and a side wall surrounding the filtration layer. The scraper device collects water, filters the water through the filtration layer, and purifies the water. A scraper is provided for scraping unnecessary substances formed on the surface of the filtration layer of the pond in a state where water is retained, and the unnecessary substances scraped off by the scraper are floated in the accumulated water, together with the water drained from the filtration pond. A scraper device for reforming the filtration layer by discharging unnecessary substances, which is provided in the scraper device described above. The same operations and effects as described above are achieved.

  ADVANTAGE OF THE INVENTION According to the reforming method of the slow filtration pond and the reforming system of the slow filtration pond of the present invention, the apparatus can be simplified, unnecessary substances can be scraped off while leaving sand as much as possible, and the discharge of the unnecessary substances can be facilitated. Thus, it is possible to facilitate the treatment of unnecessary substances after the discharge, and to improve the reforming efficiency. Further, according to the scraper device of the present invention, a simple structure effective for the reforming method of the slow filtration pond and the reforming system of the slow filtration pond is provided, and the scraping of the unnecessary material can be surely performed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows the reforming method and reforming system of the slow filtration pond which concern on embodiment of this invention. In the scraper device according to the embodiment of the present invention used in the reforming system of the slow filtration pond according to the embodiment of the present invention, a perspective view showing a main configuration including the scraper in a state when the scraper is moved forward. is there. In the scraper device according to the embodiment of the present invention used in the reforming system of the slow filtration pond according to the embodiment of the present invention, a perspective view showing a main configuration including the scraper in a state when the scraper is moved back. is there. It is a cross-sectional view showing the expanded metal which constitutes the scraper of the scraper device according to the embodiment of the present invention in relation to its towing direction R. 2A and 2B show an expanded metal structure constituting a creper of a scraper device according to an embodiment of the present invention, wherein FIG. 1A is a plan view of a main part, and FIG. FIG. 4 is a diagram showing a configuration of a reversing mechanism to which a cord is attached in the scraper device according to the embodiment of the present invention. FIG. 4 is a diagram illustrating an operation of the scraper in the scraper device according to the embodiment of the present invention. It is a top view which shows the reforming method and reforming system of the slow filtration pond which concerns on another embodiment of this invention. It is a principal part perspective view which shows the scraper apparatus which concerns on another embodiment of this invention.

  Hereinafter, a method for reforming a slow filtration pond, a reforming system for a slow filtration pond, and a scraper device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The method for reforming a slow filtration pond according to the embodiment of the present invention is realized by the reforming system for a slow filtration pond according to the embodiment of the present invention. I do. Further, the scraper device according to the embodiment of the present invention is used in the reforming system of the slow filtration pond according to the embodiment of the present invention, and therefore, the description will be made in the present reforming system.

  As shown in FIG. 1, a slow filtration pond reforming system K according to an embodiment of the present invention is used for a slow filtration pond 1. The slow filtration pond 1 has a filtration layer 2 in which filter sand is laminated on the surface side and a side wall 3 erected surrounding the filtration layer 2, and stores water to filter water by the filtration layer 2. It is a well-known thing that performs water purification. In the filtration layer 2, a function of removing suspended substances in water by filtration and removing dissolved components and odor components in water by a biochemical action of a biofilm propagated on the surface layer of the filtration layer 2 accompanying the filtration. Have. However, biofilms and the like accumulate on the surface of the filtration layer 2 with the passage of time, so that unnecessary matter F (FIG. 7) increases and water gradually becomes difficult to pass. Unnecessary substances F are removed.

The reforming system K of the present filtration basin is for reforming the filtration bed 2 by discharging unnecessary substances F formed on the surface of the filtration bed 2 of the slow filtration basin 1 in a state where water is retained. As shown in FIG. 1, the filtration pond 1 includes a filtration layer 2 having a rectangular shape as viewed from a plane, and four side walls 3 (3 a, 3 b, 3 c, 3 d) standing around the filtration layer 2. It is configured. The size of the filtration pond 1 is, for example, 29.4 m in width, 36.9 m in length (1075 m ^{2 in} filtration layer area), and about 900 mm in water depth. The size of the filtration pond 1 is not limited to this. FIG. 1 shows one in which a plurality of filtration ponds 1 are provided in series.

As shown in FIG. 1, the reforming system K of the present filtration basin 1 includes a scraper device S provided with a scraper 10 for scraping off unnecessary substances F on the surface of the filtration layer 2, and a water supply unit 11 for supplying water to the filtration basin 1. And a drain port 12 provided at an upper portion of the filtration pond 1 to discharge the inflow water so that water in the filtration pond 1 flows in. The unnecessary matter F scraped by the scraper 10 of the scraper device S is provided. The unnecessary material F is suspended in the accumulated water (FIG. 7), and is discharged together with the water discharged from the drain port 12. From the water supply unit 11, for example, 100 m ³ / hr of, for example, pretreated river water is supplied. The drain port 12 is formed, for example, by an opening of a drain pipe (not shown) for guiding drain water to the outside of the filtration pond 1, and is provided at one corner of the filtration pond 1, or two or more. A plurality of corners are provided, one for each (FIG. 1 shows a case where two are provided). The diameter of the drain port 12 is set to, for example, 200 mm.

  As shown in FIGS. 1 to 7, the scraper device S according to the embodiment includes a scraper 10. The scraper 10 has a net plate shape having an outer surface 13 abutting on the surface of the filtration layer 2. Is formed. More specifically, the scraper 10 is formed in a rectangular shape as a whole, and as shown in FIGS. 2 to 4, is formed of a metal in which openings 15 are regularly arranged and formed by strands 14 having a rectangular cross section by stretching. Of expanded metal 16. The expanded metal 16 is made of metal such as iron, galvanized steel, stainless steel, or the like. A row of cuts having predetermined widths at predetermined pitches P is formed on a metal plate. It is well-known that openings are formed in the cut portions by forming the metal plates in a line perpendicular to the cut direction by arranging the cut lines so that (1/2) P phase is shifted. belongs to. The opening 15 is formed in a flat diamond shape, a flat hexagonal shape, a regular square shape, or the like.

In the embodiment, for example, a so-called S type formed of stainless steel and having the opening 15 formed in a flat rhombus shape is used. For example, JIS standard XS43 (opening width SW in the short direction is 22 mm, long side The opening size LW in the direction is 50.8 mm, the thickness T of the strand size is 3.2 mm, the width W is 3.5 mm, the total thickness D is 7.7 mm, the unit weight is 8 kg / m ² , and the opening ratio is 66%. Is used. Further, the one having an overall vertical dimension (transverse dimension) La of 914 mm and an overall lateral dimension (longitudinal dimension) Lb of 1829 mm is used. The expanded metal 16 is not limited to this, and a metal having an appropriate standard can be selected.
Since the expanded metal 16 is relatively heavy, the outer surface 13 can be easily brought into contact with the surface of the filtration layer 2, and the member constituting the mesh opening 15 is a strand 14 having a rectangular cross section. Unnecessary material F can be scraped off by the edge of, so that the scraping can be reliably performed.

  Further, the scraper device S is provided with a cord 20 that is engaged with the scraper 10 and pulls and moves the scraper 10 on the side wall 3 of the filtration pond 1. The cord 20 is made of, for example, a rope. The cord 20 is attached to the scraper 10 such that the direction in which the scraper 10 is pulled is the direction in which the expanded metal 16 extends. Further, as shown in FIG. 4, the cord body 20 has a structure in which the strand 14 is formed with respect to the outer surface line forming the outer surface 13 of the scraper 10 in a cross section cut along the extending direction of the expanded metal 16 of the scraper 10. Assuming that the inclination angle on the acute angle side formed by the surface is θ, the scraper 10 can be engaged so that the acute angle side of the inclination angle θ of the strand 14 faces the traction direction R.

  Specifically, as shown in FIGS. 1, 2, 3, 6, and 7, the cord 20 reaches one side wall 3 (3 a) of the pair of side walls 3 facing each other in one direction X. It is provided with one cord 21 and the other cord 22 reaching the other sidewall 3 (3b) of the pair of side walls 3 facing each other in one direction X. In the scraper device S, the scraper 10 can be turned over so that the acute angle side of the inclination angle θ of the strand 14 is oriented in the towing direction R during the towing by the one rope 21 and the towing by the other rope 22, respectively. An inversion mechanism 30 is provided. More specifically, as a cord body 20, a binding cord body 23 connected to the ends of the one cord body 21 and the other cord body 22 on the scraper 10 side and attached to the scraper 10 via the reversing mechanism 30. Is provided. Both ends of the tether 23 are respectively attached to both ends of one end 10 a in the pulling direction of the scraper 10, and the center thereof is locked by the reversing mechanism 30.

  The reversing mechanism 30 is for reversing the direction of rotation about an axis Q1 orthogonal to the outer surface 13 of the scraper 10, and as shown in FIG. 6, a shaft 31 and a pair of rotatably provided on the shaft 31. Of the one rope 21 and the other rope 22 on the scraper 10 side are connected to a ring-shaped portion 34 provided on one of the bearings 32. The center of the tether 23 is locked to a ring 35 provided on the other bearing 33. By rotating the other bearing part 33 by 180 ° with respect to the one bearing part 32, the direction of the scraper 10 can be reversed so that the acute angle side of the inclination angle θ of the strand 14 faces the traction direction R. In the embodiment, this inversion is performed manually. In addition, since the binding cable 23 is V-shaped and is towed by the one cable 21 or the other cable 22, the direction of the scraper 10 is set at the acute angle side of the inclination angle θ of the strand 14 during towing. It can be oriented in the direction of traction.

  Further, the scraper device S includes a traction mechanism 40 for traction of the rope 20. The traction mechanism 40 is provided on the one side wall 3 (3a) and moves the scraper 10 by pulling the one-side cord body 21 from the one side wall 3 (3a) so that the outer surface 13 of the scraper 10 comes into contact with the surface of the filtration layer 2. The electric one-side winch 41 for performing the forward movement and the other rope body 22 provided on the other side wall 3 (3b) to pull the other rope 22 from the other side wall 3 (3b) to move the scraper 10 to the outer surface 13 on the surface of the filtration layer 2 An electric other winch 42 is provided for performing a reciprocating movement of bringing the abutment into contact and moving. In the one winch 41 and the other winch 42, as shown in FIG. 7, the traction force is set so that the traction side of the scraper 10 does not rise due to traction. There is no problem if the front end of the scraper 10 in the towing direction rises or comes into contact with the ground and may slightly move up and down.

  Further, the scraper device S is provided on one side wall 3 (3a), and supports one winch 41 movably along the other direction Y orthogonal to the one direction X, and the other side wall 3 (3b). And the other rail 44 for supporting the other winch 42 movably along the other direction Y orthogonal to the one direction X.

  Therefore, when the reforming is performed by the reforming system K of the slow filtration pond 1 according to this embodiment, as shown in FIG. 1, first, the scraper 10 of the scraper device S is moved to, for example, the other side wall 3 ( 3b), which is located on one of the side walls 3 facing the other direction Y, for example, on the side wall 3 (3c) side. In this case, the direction of the scraper 10 is set such that the acute angle side of the inclination angle θ of the strand 14 is directed to the pulling direction in which the one-side cable 21 is pulled. Water is supplied from the water supply unit 11 and water is discharged from the drain port 12. In this state, the one-side winch 41 is operated, and the one-side cord 21 is pulled. Thereby, the unnecessary matter F on the surface of the filtration layer 2 is scraped off by the scraper 10 and floated in the accumulated water.

  On the other hand, when the scraper 10 reaches the one side wall 3 by the pulling of the winch 41, the operation of the one winch 41 is stopped. Then, the scraper 10 is manually inverted by the reversing mechanism 30, and this time, the direction of the scraper 10 is set so that the acute angle side of the inclination angle θ of the strand 14 is directed to the pulling direction in which the other cable body 22 is pulled. In addition, the one winch 41 is moved on one rail 43 to one of the other side of the side wall 3 facing the other direction Y, in FIG. 1, the side wall 3 (3d), and the other winch 42 is moved to the other side Y in the other direction Y. 1. The scraper 10 is moved on the other rail 44 to one of the other sides of FIG. 1, ie, the side wall 3 (3d) in FIG. 1, and the scraper 10 is moved to the surface of the filtration layer 2 that has not been scraped. The movement of the scraper 10 is performed for a distance slightly shorter than the longitudinal dimension of the scraper 10.

  In this state, the other winch 42 is operated, and the other cable body 22 is pulled. Thereby, the unnecessary matter F on the surface of the filtration layer 2 is scraped off by the scraper 10 and floated in the accumulated water. If the scraper 10 reaches the other side wall 3 (3b) due to the pulling of the other winch 42, the operation of the other winch 42 is stopped. Then, the scraper 10 is manually inverted by the reversing mechanism 30, and the direction of the scraper 10 is set so that the acute angle side of the inclination angle θ of the strand 14 is directed to the pulling direction in which the one cord 21 is pulled. In addition, the one winch 41 is moved on one rail 43 to one of the other side of the side wall 3 facing the other direction Y, in FIG. 1, the side wall 3 (3d), and the other winch 42 is moved to the other side Y in the other direction Y. 1. The scraper 10 is moved on the other rail 44 to one of the other sides of FIG. 1, ie, the side wall 3 (3d) in FIG. 1, and the scraper 10 is moved to the surface of the filtration layer 2 that has not been scraped. The movement of the scraper 10 is performed for a distance slightly shorter than the longitudinal dimension of the scraper 10. Then, in the same manner as described above, the one-side winch 41 is operated, and the one-side cable body 21 is pulled.

  In this manner, the surface of the filtration layer 2 is sequentially scraped off by the scraper 10 in a belt shape. When the scraper 10 cuts the material to the other side of the side wall 3 facing the other direction Y, and in FIG. 1 to the side wall 3 (3d), the process ends. If necessary, the surface of the filtration layer 2 that has been once removed may be repeatedly cut twice or three times, and the number of times of cutting may be appropriately determined.

  In this case, as shown in FIG. 7, since the scraper 10 is formed in a mesh shape with the expanded metal 16, a large number of members forming the mesh (opening 15) are arranged in the moving direction, so that the filtration Since the surface of the layer 2 is repeatedly shaved, the unnecessary substances F on the surface of the filtration layer 2 can be reliably shaved off. Further, since the scraped-off unnecessary material F passes through the mesh (opening 15) of the scraper 10, it can be easily floated in water as compared with a case where the scraped-off unnecessary material F is simply scraped off with a plate. Further, in this case, some of the contaminated sand on the surface of the filtration layer 2 may be scraped off. However, since the sand is heavy, it temporarily rises, but sinks, so that the unnecessary matter F to be removed can be floated. . Since unnecessary substances F are scraped off from the surface of the filtration layer 2, the filtration function of the filtration layer 2 is restored. In addition, the sand that has been scraped off to some extent remains settled, and some biofilm remains, so effective biofilm recovery is quick and the biochemical effects of biofilm can be maintained. it can.

  In addition, since the scraper 10 is moved by using the cord 20, the scraper 10 can be easily moved. Further, since the cable body 20 is towed on the side wall 3, the operation becomes easy. Since the towing is performed by the towing mechanism 40, the towing can be easily performed. Further, since the cable body 20 is towed by the one winch 41 and the other winch 42, the towing is facilitated, the operability is improved, and the workability can be greatly improved. Furthermore, since the position change movement of the one winch 41 and the other winch 42 in the other direction Y is performed on the one rail 43 and the other rail 44, the movement becomes easy, and accordingly, the operability is improved and the workability is greatly improved. Can be improved.

  Further, in shaving off unnecessary materials F on the surface of the filtration layer 2, an expanded metal 16 is used as the scraper 10, and since the expanded metal 16 is relatively heavy, the outer surface 13 is formed on the surface of the filtration layer 2. Can be easily contacted, and the members constituting the mesh opening 15 are the strands 14 having a rectangular cross section, so that the unnecessary material F can be scraped off by the edges of the strands 14, so that the scraping is performed reliably. be able to. Further, since the pulling direction R of the scraper 10 is set to be the extending direction of the expanded metal 16, the continuity of the edges of the strands 14 in the direction orthogonal to the pulling direction R is good, so that unnecessary materials are surely removed. Can be scraped. In particular, since the opening 15 which is the mesh of the scraper 10 is flat, the stretching direction is the shorter direction of the opening 15, and therefore, the strands 14 in the longitudinal direction of the opening 15 mainly cover the surface of the filtration layer 2. Since the length of the strand 14 in the longitudinal direction is larger than that in the lateral direction, unnecessary material can be reliably removed.

  Moreover, in the scraper 10, since the acute angle side of the inclination angle θ of the strand 14 is in the traction direction, the resistance of the edge of the strand 14 to bite into the surface of the filtration layer 2 is smaller than that of the obtuse angle side, so that the movement is reduced. It can be performed smoothly. In this case, since the direction of the scraper 10 can be reversed by the reversing mechanism 30 so that the acute angle side of the inclination angle θ of the strand 14 faces the pulling direction, the direction of the scraper 10 can be changed without changing the direction of the rope 20. Thus, the acute angle side of the inclination angle θ of the scraper 10 can be directed to the towing direction, so that the operation can be easily performed. Therefore, the movement of the scraper 10 can be surely performed smoothly, and the surface of the filtration layer 2 can be evenly removed, so that the working efficiency can be improved.

  Further, the one winch 41 moves the scraper 10 through the one cord 21 by moving the scraper 10 by bringing the outer surface 13 into contact with the surface of the filter layer 2, and the other winch 42 causes the scraper 10 to move through the other cord 22. As the scraper 10 is moved backward by moving the scraper 10 with its outer surface 13 in contact with the surface of the filtration layer 2, the scraping efficiency is extremely improved. Further, the winches 41 and 42 facilitate towing, improve operability, and greatly improve workability.

  Since water is supplied from the water supply unit 11 to the filtration pond 1 and discharged from the drain port 12, the unnecessary matter F is discharged together with the discharged water. Therefore, the discharge of the unnecessary material F is facilitated, and the processing of the sand after the discharge is not required. Therefore, the processing of the unnecessary material becomes extremely easy, and accordingly, the reforming efficiency can be improved. As described above, since the filtration layer 2 can be reformed only by moving the mesh plate-shaped scraper 10 of the scraper device S, the entire system can be simplified.

  That is, the scraper 10 is moved from the one side wall 3 by the one cord 21 by moving the scraper 10 by bringing the outer surface 13 into contact with the surface of the filtration layer 2, and the scraper 10 is moved from the other side wall 3 by the other cord 22 to the outer surface. 13 is moved in contact with the surface of the filtration layer 2 to move the scraper 10, the one rope 21 and the other rope 22 are moved in the other direction Y orthogonal to the one direction X, and the outside of the scraper 10 is moved. By performing the position change movement that changes the contact position of the side surface 13 with respect to the surface of the filtration layer 2, and scraping off the unnecessary matter F by the scraper 10, the surface of the filtration layer 2 can be scraped uniformly, and the scraping is performed. Since the unnecessary substances F can be discharged by the flow of water, the filtration layer 2 can be reformed with a simple operation, and the reforming efficiency can be improved.

  FIG. 8 shows a method for reforming a slow filtration pond 1 and a reforming system K according to another embodiment of the present invention. This is different from the above in that the pulling mechanism 40 is not provided, and the pulling of the rope body 20, the inversion of the scraper 10, and the movement of the scraper 10 in the other direction Y are performed manually. An operator is appropriately arranged on one side wall 3 (3a) and the other side wall 3 (3b). In this case as well, a forward movement in which the scraper 10 is moved from the one side wall 3 (3a) by the one-side cord body 21 with the outer side surface 13 of the scraper 10 in contact with the surface of the filtration layer 2, and another side line from the other side wall 3 (3b). A backward movement in which the scraper 10 is moved by bringing the outer side surface 13 into contact with the surface of the filtration layer 2 by the body 22, and the position of the scraper 10, the one-side body 21 and the other-side body 22 is moved in the other direction orthogonal to one direction X Y to move the outer surface 13 of the scraper 10 to change the contact position with respect to the surface of the filtration layer 2, and scrape off the unnecessary material F by the scraper 10. Since the scraps can be uniformly scraped off and the scraped-off unnecessary substances F can be discharged by the flow of water, the filtration layer 2 can be reformed with a simple operation, and the reforming efficiency can be improved. . Other operations and effects are the same as those described above.

  FIG. 9 shows a scraper device S according to another embodiment of the present invention. The scraper device S uses the same expanded metal 16 as the scraper 10 as described above, but differs in the configuration of the cord 20 and the reversing mechanism 30. The cord 20 is connected to one side wall 3 (3a) of the pair of side walls 3 facing each other in one direction X, and the other of the pair of side walls 3 facing each other in one direction X. The other rope body 22 reaching the side wall 3 (3b) is connected to one end of the one rope body 21 on the scraper 10 side and is connected to one end edge 10a of the scraper 10 via one member 37 of a reversing mechanism 30 described later. Is connected to the scraper 10 side end of the other cable body 22 and is connected to the other end 10b of the scraper 10 via the other member 38 of the reversing mechanism 30 described later. On the other hand, a tying cord 26 is provided. On the other hand, both ends of the tying cord 25 are respectively tied to both ends of one end 10 a in the pulling direction of the scraper 10, and the center is locked to one member 37 of the reversing mechanism 30. On the other hand, both ends of the tying cord 26 are tied to both ends of the other side edge 10b in the pulling direction of the scraper 10, respectively, and the center is locked to the other member 38 of the reversing mechanism 30.

  The reversing mechanism 30 is for reversing the front and back by rotating about an axis Q <b> 2 along the extending direction of the expanded metal 16 of the scraper 10, and includes one member 37 and the other member 38. Referring to FIG. 6, each of the one member 37 and the other member 38 is formed by a so-called sobel joint including the shaft 31 and a pair of bearing portions 32 and 33 rotatably provided on the shaft 31. I have. One end of the rope body 21 on the side of the scraper 10 is connected to a ring-shaped portion 34 provided on the bearing portion 32 of the one member 37, and the center of the one connected cable body 25 is provided on the other bearing portion 33. It is locked to the part 35. Further, the end of the other cable body 22 on the scraper 10 side is bonded to a ring-shaped portion 34 provided on the bearing portion 32 of the other member 38, and the center of the other cable body 26 is provided on the other bearing portion 33. It is locked on the ring-shaped portion 35.

  In the reversing mechanism 30, the scraper 10 can be manually turned over around the axis Q <b> 2 along the extending direction of the expanded metal 16 by hand. The scraper device S according to another embodiment using the reversing mechanism 30 can be used for the reforming system S of the slow filtration pond, as described above, and produces the same operation and effect as above. Can be done.

  In the above embodiment, the engagement of the cord body 20 with the scraper 10 is not limited to the above-described embodiment, and may be appropriately changed. Further, the configuration of the reversing mechanism 30 is not limited to the configuration described above, and may be appropriately changed. Further, in the above-described embodiment, the present invention is applied to the filtration pond 1 including the rectangular filtration layer 2 and the four side walls 3, but is not necessarily limited thereto. Needless to say, the present invention can be applied to any shape of filtration layer. In this case, the traction of the scraper 10 may be appropriately changed according to the shape of the filtration layer. In short, the present invention is not limited to the embodiments of the present invention described above, and those skilled in the art will appreciate that many modifications may be made to these illustrative embodiments without departing substantially from the novel teachings and advantages of the present invention. And many of these changes are within the scope of the invention.

K Reforming system of slow filtration pond 1 Slow filtration pond 2 Filtration layer 3 (3a, 3b, 3c, 3d) Side wall X One direction Y Other direction F Unnecessary material S Scraper device 10 Scraper 10a One end edge 10b Other end edge 11 Water supply unit 12 Drain port 13 Outer side surface 14 Strand 15 Opening 16 Expanded metal 20 Cable body R Pulling direction 21 One cable body 22 Other cable body 23 Binding cable body 25 One binding cable body 26 Other binding cable body 30 Reversing mechanism 31 Shafts 32, 33 Bearings 34, 35 Ring-shaped part 37 One member 38 Other member 40 Traction mechanism 41 One winch 42 Other winch 43 One rail 44 Other rail

Claims (17)

Unnecessary matters formed on the surface of the filtration layer of a slow filtration pond that has a filtration layer and side walls that are erected around the filtration layer, collects water, filters the water through the filtration layer, and purifies the water. In a method of reforming a slow filtration pond in which water is discharged in a state of retaining water to reform the filtration layer,
Using a scraper to scrape off unnecessary substances on the surface of the filtration layer, forming the scraper in a mesh plate shape having an outer surface in contact with the surface of the filtration layer, and applying the scraper to the outer surface of the filtration layer. It is moved in contact with it, scraping off unnecessary substances on the surface of the filter layer and suspending it in the accumulated water, supplying water to the filter pond and draining from the drain port, and discharging unnecessary substances together with the drained water. A method for reforming a slow filtration pond, characterized in that:   The cable according to claim 1, wherein a rope that pulls and moves the scraper is engaged with the scraper, and the scraper is pulled and moved on the side wall of the filtration pond. A method for reforming fast filtration ponds. The filtration pond is configured to include a rectangular filtration layer viewed from a plane, and four side walls standing upright surrounding the filtration layer,
One of the pair of side walls opposed to each other in one direction is engaged with one of the side walls of the scraper, and the other of the two ropes is connected to the other side wall. The forward movement to move the scraper by contacting the outer side surface thereof to the surface of the filtration layer by the body, and the outer side surface of the scraper is brought into contact with the surface of the filtration layer by the other cord from the other side wall. Moving back and moving the scraper, the one cord body and the other cord body in the other direction orthogonal to the one direction to change the contact position of the outer surface of the scraper with the surface of the filtration layer. 3. The method for reforming a slow filtration pond according to claim 2, wherein the scraper is moved to scrape off unnecessary substances.   4. The method for reforming a slow filtration pond according to claim 3, wherein the scraper is made of expanded metal made of metal in which openings are regularly arranged by strands having a rectangular cross section by stretching and forming. .   5. The method for reforming a slow filtration pond according to claim 4, wherein a direction in which the scraper is pulled is a direction along a direction in which the expanded metal is extended.   In a cross section cut along the stretching direction of the expanded metal of the scraper, when the angle of inclination of the acute angle side formed by the surface of the strand with respect to an outer surface line forming the outer surface of the scraper is θ, 6. The method for reforming a slow filtration pond according to claim 5, wherein an acute angle side of the angle of inclination of the strand is directed to the traction direction.   When switching from the forward movement to the backward movement, or when switching from the backward movement to the forward movement, the scraper is inverted with respect to the cable body such that the acute angle side of the inclination angle θ of the scraper faces the towing direction. The method for reforming a slow filtration pond according to claim 6, wherein Unnecessary matters formed on the surface of the filtration layer of a slow filtration pond that has a filtration layer and side walls that are erected around the filtration layer, collects water, filters the water through the filtration layer, and purifies the water. In a reforming system of a slow filtration pond that reforms the filtration layer by discharging water in a state where water is stored,
A scraper device provided with a scraper for scraping off unnecessary substances on the surface of the filtration layer, a water supply unit for supplying water to the filtration pond, and an opening provided at an upper part of the filtration pond so that water in the filtration pond flows in. A drain port for discharging the inflowing water, and a slow speed in which unnecessary substances scraped off by the scraper of the scraper device are floated in accumulated water, and the unnecessary substances are discharged together with the water discharged from the drain port. A filter pond reforming system,
A slow filtration pond reforming system, wherein the scraper of the scraper device is formed in a mesh plate shape having an outer surface in contact with the surface of the filtration layer.   9. The reformer for a slow filtration pond according to claim 8, wherein the scraper device is provided with a rope body which is engaged with the scraper and pulls and moves the scraper on a side wall of the filtration pond. system.   10. The system for reforming a slow filtration pond according to claim 9, wherein the scraper device includes a pulling mechanism for pulling the rope.   The slow filtration according to any one of claims 8 to 10, wherein the scraper is made of a metal expanded metal in which openings are regularly arranged and formed by strands having a rectangular cross section by stretching and forming. Pond reforming system.   The scraper device is provided with a rope that is engaged with the scraper and pulls and moves the scraper on a side wall of the filtration pond, and the pulling direction of the scraper is such that the expanded metal extends the expanded metal. 12. The reforming system of a slow filtration pond according to claim 11, wherein the scraper is engaged with the scraper so as to be oriented in the opposite direction.   In the cross section of the rope body, which is cut along the expanding direction of the expanded metal of the scraper, the angle of inclination of the acute angle side formed by the surface of the strand with respect to the outer surface line forming the outer surface of the scraper is defined as θ. 13. The reforming system for a slow filtration pond according to claim 12, wherein, when the scraper is used, the scraper can be attached so that the acute angle side of the inclination angle [theta] of the strand faces the traction direction. The filtration pond is configured to include a rectangular filtration layer viewed from a plane, and four side walls standing upright surrounding the filtration layer,
The above-mentioned cord body includes one cord body reaching one side wall of a pair of side walls facing each other in one direction, and another cord body reaching the other side wall of the pair of side walls facing each other in one direction. Configure
The scraper device has a reversing mechanism that enables the scraper to be reversed so that the acute angle side of the inclination angle θ of the strand is in the pulling direction when the one rope body and the other rope body respectively tow. 14. The reforming system for a slow filtration pond according to claim 13, wherein:   The scraper device is provided with a traction mechanism for pulling the rope body, and the traction mechanism is provided on the one side wall and pulls the one rope body from the one side wall to make the scraper an outer surface of the filtration layer. A winch for making a forward movement to be brought into contact with the surface, and a winch provided on the other side wall, pulling the other cord from the other side wall, and bringing the scraper into contact with the outer surface of the scraper against the surface of the filtration layer. 15. The slow filtration pond reforming system according to claim 14, further comprising: a winch for performing a reciprocating movement.   The scraper device is provided on the one side wall, the one rail movably supporting the one winch along the other direction orthogonal to the one direction, and the one side provided on the other side wall, and the other winch is provided in the one direction. And the other rail movably supported along the other direction perpendicular to the direction of movement of the scraper, the one rope body and the other rope body are moved in the other direction perpendicular to the one direction to move the outer surface of the scraper. 16. The slow filtration pond reforming system according to claim 15, wherein a position changing movement for changing a contact position with respect to a surface of the filtration layer is enabled. Unnecessary matters formed on the surface of the filtration layer of a slow filtration pond that has a filtration layer and side walls that are erected around the filtration layer, collects water, filters the water through the filtration layer, and purifies the water. A scraper that scrapes off the wastewater in a pool of water.The scraper scrapes the wastewater into the pooled water so that the wastewater is discharged together with the water drained from the filter pond. A scraper device adapted to
A scraper device according to any one of claims 8 to 16.

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