JP2020062638A - Transfer system - Google Patents

Abstract

To provide a transfer system where a contaminant contained in a received liquid is settled and the scattering-up of the contaminant is suppressed while sufficiently moving the contaminant.SOLUTION: In a transfer system including a space formation member 8 extending along a bottom 1a, forming a space S2 whose upper end part 82 is closed and disposing a suction port 81 being separated from the bottom 1a below the upper end part 82 and a discharge port 7 discharging a fluid into the space S2, the discharge port 7 has a flat shape, is positioned above the suction port 81 and discharges the fluid toward a downstream side in a transfer direction of the contaminant contained in a received liquid.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a transfer system in which contaminants contained in a received liquid settle.

  The sewage treatment system receives wastewater such as sewage or rainwater, settles the sand contained in the wastewater to the bottom of the pond, and then moves in a predetermined direction to collect the sand deposited on the bottom of the pond, and gathers it. Some have a settling basin that removes sand from sewage. It is known that the sand basin is provided with a sand collecting means for moving the sand accumulated at the bottom of the basin toward the downstream side in the discharge direction of the fluid by the flow of the fluid discharged from the discharge port. In the sand collection using this fluid, the deposited sand may be scattered by the discharged fluid, and it is important how to suppress the scattering of the sand. Conventionally, inclined plates, which are inclined downward toward the downstream side in the discharge direction, are arranged above the bottom of the pond at intervals along the discharge direction, and the inclined plates are used to prevent sand from rising. See, for example, Patent Document 1).

  In addition, the sewage treatment system receives the water from which the sand has been removed in the settling basin, settles the sludge contained in the received water to the bottom of the pond, and then collects the sludge accumulated in the bottom of the pond in a predetermined direction. Some have a settling basin that removes the collected sludge from the sewage. Also in this settling basin, it is known that sludge accumulated on the bottom of the basin is provided with a moving unit that moves toward the downstream side in the discharge direction of the fluid by the flow of the fluid discharged from the discharge port. Since sludge has a particle size smaller than that of sand, it is easier to sprinkle than sand, and it is more important to control how sludge is sprinkled. Conventionally, a shielding plate that is inclined downward toward the downstream side in the discharge direction is provided above the discharge nozzle provided at the bottom of the sedimentation basin, and it is attempted to prevent sand from rising by the shield plate (for example, patent References such as 2).

JP, 9-70503, A Japanese Utility Model Publication No. 64-56807

  However, in the inclined plate described in Patent Document 1, since the inclined plates are arranged so as to face each other in the discharge direction, the fluid discharged from the discharge port may be blocked and the sand may not move sufficiently. is there. Therefore, if the discharge pressure of the discharge port is increased in order to sufficiently move the sand, the sand may scatter along the inclined plate due to the momentum of the discharged fluid.

  Further, also in the shielding plate described in Patent Document 2, since the shielding plate is arranged so as to face in the ejection direction, there is the same problem as in Patent Document 1.

  In addition to the sedimentation basin and sedimentation basin, for example, it is possible to move the contaminants such as sediment that flowed into reservoirs such as dam lakes in one direction and discharge the collected contaminants such as sediment. Also in this case, it is preferable to prevent the contaminants such as earth and sand deposited on the bottom of the dam lake from moving up.

  In view of the above circumstances, it is an object of the present invention to provide a transfer system which is devised so as to suppress the rise of contaminants while sufficiently moving the contaminants.

The transfer system of the present invention for solving the above-mentioned object is a transfer system in which contaminants contained in a received liquid settle to the bottom,
A space forming member that extends along the bottom portion, forms a space with an upper end portion closed, and has an opening provided below the upper end portion and separated from the bottom portion,
A discharge port for discharging a fluid into the space,
The discharge port has a flat shape, is positioned above the opening, and discharges the fluid toward the downstream side in the transport direction of the contaminant.

Also, a transfer system in which contaminants contained in the received liquid settle to the bottom,
A space forming member that extends along the bottom portion, forms a space with an upper end portion closed, and has an opening provided below the upper end portion and separated from the bottom portion,
A discharge port for discharging a fluid into the space,
The space is such that the lower end portion connected to the opening is narrowed toward the opening,
The discharge port may discharge the fluid toward a downstream side in the transport direction of the contaminant.

Also, a transfer system in which contaminants contained in the received liquid settle to the bottom,
A space forming member that extends along the bottom portion, forms a space with an upper end portion closed, and has an opening provided below the upper end portion and separated from the bottom portion,
A discharge port for discharging a fluid into the space,
The space may have a lower end portion that is connected to the opening and is narrowed toward the opening.

Also, a transfer system in which contaminants contained in the received liquid settle to the bottom,
A space extending member that extends along the bottom portion, forms a space in which the upper end portion is closed, and has a suction port provided below the upper end portion and separated from the bottom portion,
A discharge port for discharging a fluid into the space,
The suction port functions as an opening for sucking the contaminants accumulated on the bottom into the space due to a pressure difference between the space inside and the space outside caused by the fluid being discharged from the discharge port. And
The space forming member functions as a path in which the contaminants sucked into the space move toward the downstream side in the discharge direction of the fluid when the fluid is discharged from the discharge port,
The space may be a transfer system in which a lower end portion connected to the suction port is narrowed toward the suction port.

  Further, in this transfer system, the discharge port may have a flat shape.

Also, a transfer system in which contaminants contained in the received liquid settle to the bottom,
A space extending member that extends along the bottom portion, forms a space in which the upper end portion is closed, and has a suction port provided below the upper end portion and separated from the bottom portion,
A discharge port for discharging a fluid into the space,
The suction port functions as an opening for sucking the contaminants accumulated on the bottom into the space due to a pressure difference between the space inside and the space outside caused by the fluid being discharged from the discharge port. And
The space forming member functions as a path in which the contaminants sucked into the space move toward the downstream side in the discharge direction of the fluid when the fluid is discharged from the discharge port,
The discharge port may have a flat shape.

  Further, in this transfer system, the discharge port may discharge the fluid in a horizontal direction or a substantially horizontal direction.

  Further, in this transfer system, the discharge port may be located below the center of the space forming member and above the suction port.

Further, in this transfer system, a groove formed in the bottom portion and opened upward is provided,
The suction port is one that opens in the groove, and functions as an opening that sucks a contaminant accumulated in the groove into the space by discharging a fluid from the discharge port,
The discharge port may discharge the fluid into the space instead of discharging the fluid toward the contaminants accumulated in the groove and outside the space.

  Further, in this transfer system, the discharge port may be located below the center of the groove.

Also, a transfer system in which contaminants contained in the received liquid settle to the bottom,
A space extending member that extends along the bottom portion, forms a space in which the upper end portion is closed, and has a suction port provided below the upper end portion and separated from the bottom portion,
A discharge port for discharging a fluid into the space,
The suction port functions as an opening for sucking the contaminant deposited on the bottom into the space by discharging a fluid from the discharge port,
The space forming member functions as a path in which the contaminant sucked into the space moves toward the downstream side in the discharge direction of the fluid when the fluid is discharged from the discharge port,
The suction port is one in which the lower end of the space forming member opens downward.
The space may have a lower end portion that is connected to the suction port and is narrowed toward the suction port.

  Further, in this transfer system, the discharge port may be located below the center of the space forming member and above the suction port.

  Further, in this transfer system, the discharge port may have a flat shape.

Further, in this transfer system, the bottom portion is formed with a groove,
In the space forming member, the suction port is opened in the groove, and the height position of the upper end portion is substantially the same as the opening of the groove or is lower than the opening of the groove. Good.

Further, in this transfer system, the bottom portion is formed with a groove,
The groove has a shape in which the upper part of the cylindrical body is cut out,
The space forming member may have a shape in which the suction port opens in the groove and a lower portion of a cylindrical body is cut out.

In addition, the sand contained in the received water is a sand basin where the sand settles at the bottom of the pond,
A space extending member that extends along the pond bottom portion, forms a space in which the upper end portion is closed, and has a suction port provided below the pond bottom portion and spaced from the pond bottom portion,
A discharge port for discharging a fluid into the space,
The suction port functions as an opening for sucking the sand deposited on the bottom of the pond into the space by discharging a fluid from the discharge port,
The space forming member functions as a path in which the sand sucked into the space moves toward the downstream side in the discharge direction of the fluid when the fluid is discharged from the discharge port,
The discharge port may be a sand basin which discharges fluid at a flow velocity of 8 m / sec or more.

  Further, the discharge port may discharge the fluid at a discharge pressure of 0.05 MPa or more and 0.3 MPa or less.

  Further, the discharge port may be positioned below the center of the space forming member and above the suction port.

  Further, the discharge port may have a flat shape.

Further, the pond bottom has a groove formed,
In the space forming member, the suction port is opened in the groove, and the height position of the upper end portion is substantially the same as the opening of the groove or is lower than the opening of the groove. Good.

Further, the pond bottom has a groove formed,
The groove has a shape in which the upper part of the cylindrical body is cut out,
The space forming member may have a shape in which the suction port opens in the groove and a lower portion of a cylindrical body is cut out.

Further, the suction port is one in which the lower end of the space forming member is opened downward.
The space may have a lower end portion that is connected to the suction port and is narrowed toward the suction port.

In addition, a sand basin where the sand contained in the received water settles at the bottom of the pond,
A space extending member that extends along the pond bottom portion, forms a space in which the upper end portion is closed, and a suction port provided below the upper end portion and separated from the pond bottom portion.
A discharge port for discharging a fluid into the space,
The suction port functions as an opening for sucking the sand accumulated on the pond bottom into the space by discharging a fluid from the discharge port,
The space forming member functions as a path for the sand sucked into the space to move toward the downstream side in the discharge direction of the fluid when the fluid is discharged from the discharge port. It may be a sand pond.

  Here, the space forming member may have a C-shaped (arc-shaped), U-shaped, V-shaped, U-shaped cross-sectional shape, and the suction port extends along the pond bottom. Alternatively, a plurality of tubular shapes may be provided. Alternatively, the suction port may have a slit shape extending along the pond bottom.

  The space forming member itself may be in contact with the pond bottom or may be separated from the pond bottom.

  Further, the space forming member may be one in which the suction port is provided in a lower portion.

  According to this sand basin, the fluid is discharged from the discharge port into the space, so that a pressure difference is generated between the inside (the space) and the outside of the space forming member, and the sand accumulated on the bottom of the basin is removed. , Is sucked into the space through the suction port. Further, in the space, the sucked sand moves toward the downstream side in the discharge direction due to the flow of the fluid. The sand moving in the space is less likely to go out of the space forming member in the portion where the pressure difference is generated, and the sand is prevented from rising. Therefore, according to this settling basin, it is possible to prevent sand from rising while sufficiently moving the sand.

Further, in this sand basin, the suction port is one in which the lower end of the space forming member is opened downward,
The space may have a lower end portion that is connected to the suction port and is narrowed toward the suction port.

  That is, the suction port may be an opening narrowed in the width direction orthogonal to the extending direction of the space forming member, and the space may be a space expanded from the suction port. Since the suction port is a narrowed opening in this way, the sand moving in the space is less likely to come out of the space, and the sand is prevented from rising further. Further, it becomes easier to maintain the flow of the fluid in the space, and it is possible to move the sand further.

  The suction port may extend along the pond bottom.

  Further, the space forming member may have an arc shape whose cross-sectional shape is larger than ½ (for example, 3/4 arc shape).

  Further, in this sand basin, the discharge port may be arranged in the space, and the discharge port may be in the direction in which the space forming member extends, that is, the space forming member. The fluid may be discharged in a parallel direction (for example, a horizontal direction).

  By doing so, the above pressure difference is more likely to occur.

  Here, the velocity of the fluid, that is, the flow velocity, increases as the distance to the discharge port increases. Therefore, by disposing the discharge port in the space and in the vicinity of the suction port, sand is more easily sucked from the suction port.

Further, in this settling basin, the pond bottom has a groove formed,
The space forming member may have a configuration in which the suction port is opened in the groove.

  According to this aspect, the sand deposited on the bottom of the pond can be efficiently sucked into the space, and the sand collection efficiency is improved.

  The groove may have an arc-shaped cross section, and in this case, it is preferable that the groove has an arc shape larger than 1/2 (for example, a 3/4 arc shape). By doing so, it is possible to further suppress the sand accumulated in the groove from being scattered outside the groove.

Further, in a sand basin in which the sand contained in the received water sinks to the bottom of the pond, a sand removal method for removing the sand accumulated at the bottom of the basin from the sand basin,
In the space forming member, which extends along the above-mentioned pond bottom and forms a space whose upper end is closed, and which is provided below the upper end with a suction port separated from the pond bottom, a fluid is present in the space. And a sand collecting step of moving the sand accumulated on the bottom of the pond toward the downstream side in the discharge direction of the fluid,
Having a discharging step of discharging the sand that has moved to the downstream side in the discharging direction by performing the sand collecting step toward the outside of the sand basin,
In the sand collecting step, by discharging the fluid into the space, the sand accumulated on the bottom of the pond is sucked into the space from the suction port, and the sand sucked into the space is directed to the downstream side in the discharging direction. It may be a sand removal method characterized by a step of moving the sand.

  According to this sand removal method, it is possible to remove the sand from the sand basin by sufficiently moving the sand in the sand basin while suppressing the rising of the sand.

Also, in the bottom part where the contaminants contained in the received liquid have settled, a transfer system for moving the contaminants in one direction,
A space forming member that forms a space whose upper end portion is closed, and is provided with a suction port below the upper end portion and separated from the bottom portion,
A fluid supply pipe,
A discharge port for discharging the fluid supplied by the fluid supply pipe into the space,
The suction port functions as an opening for sucking the contaminant deposited on the bottom into the space by discharging a fluid from the discharge port,
The space forming member functions as a path through which the contaminants sucked into the space move toward the downstream side in the discharge direction of the fluid when the fluid is discharged from the discharge port. May be a transfer system.

  Here, the transfer system may be provided in a dam lake, and may move the sediment deposited on the bottom of the dam lake in one direction. Further, the transfer system may move the metal powder generated in a factory or the like in one direction. The received liquid may be retained by stopping the flow for the time required for the contaminants to settle, or may be flowed and retained at the flow rate required for the contaminants to settle.

  According to this transfer system, since the fluid is discharged from the discharge port into the space, a pressure difference is generated between the inside (the space) and the outside of the space forming member, and the contaminants accumulated on the bottom are removed. , Is sucked into the space through the suction port. Further, in the space, the sucked contaminant moves toward the downstream side in the discharge direction due to the flow of the fluid. The contaminants moving in the space are less likely to come out of the space forming member in the portion where the pressure difference is generated, and scattering of the contaminants is suppressed. Therefore, according to this transfer system, it is possible to suppress the scattering of the contaminant while sufficiently moving the contaminant.

Further, in the transfer system, the suction port is provided in a sedimentation basin in which sludge settles,
It may function as an opening for sucking sludge accumulated as a contaminant on the bottom of the sedimentation tank into the space.

  Here, the bottom part may be the bottom part of the settling basin, or the bottom part of a transfer path provided upstream of the bottom part and connected to the sludge pit.

Further, in the bottom portion where the contaminants contained in the received liquid have settled, a contaminant removing method for removing the contaminants accumulated on the bottom portion,
A fluid is discharged into the space in a space forming member that extends along the bottom portion and forms a space whose upper end portion is closed, and in which a suction port is provided below the upper end portion and separated from the bottom portion. And a moving step of moving the contaminants accumulated on the bottom portion toward the downstream side in the discharge direction of the fluid,
And a discharge step of discharging the contaminants that have moved to the downstream side in the discharge direction by performing the moving step,
In the moving step, by discharging a fluid into the space, the contaminants accumulated on the bottom portion are sucked into the space from the suction port, and the contaminants sucked into the space are directed toward the downstream side in the discharge direction. It may be a method of removing contaminants, which is characterized in that it is a step of moving the mixture.

  Here, the contaminant may be sludge, earth and sand, or metal powder. The received liquid may be retained by stopping the flow for the time required for the contaminants to settle, or may be flowed and retained at the flow rate required for the contaminants to settle.

  According to this contaminant removal method, it is possible to remove contaminants by sufficiently moving contaminants while suppressing scattering of contaminants.

  According to the present invention, it is possible to provide a transfer system which is devised so as to suppress the scattering of the contaminant while sufficiently moving the contaminant.

It is the top view which looked at the sand basin corresponding to one embodiment of the present invention from the upper part. It is an AA sectional view of the sand basin shown in FIG. (A) is a BB sectional view in FIG. 2, and (b) is a CC sectional view in (a). FIG. 4A is an enlarged partial cross-sectional view showing the vicinity of the most upstream end of the trough, and FIG. 4B is a partial cross-sectional view of FIG. 4A viewed from the right side. It is a flowchart which shows the flow of a sand removal method. It is sectional drawing which cut | disconnected the sand basin of 2nd Embodiment at the center of the width direction. It is DD sectional drawing of the sand basin shown in FIG. This It is a perspective view which shows the modification of a space formation member. It is a figure which shows the modification of a discharge port. It is a figure which shows the modification of the method of support of a space formation member. It is the top view which looked at the sedimentation tank in which one Embodiment of a transfer system was provided from the upper part. It is a sectional side view of the sedimentation basin shown in FIG. It is EE sectional drawing in FIG. 13A is an enlarged view showing an enlarged part G of FIG. 13, and FIG. 13B is an enlarged view showing an enlarged part H of FIG. It is a flowchart which shows the flow of a sludge removal method. It is sectional drawing which shows the aspect corresponding to FIG. 13 in the sedimentation tank in which the transfer system of 2nd Embodiment was provided. 16A is an enlarged view showing an enlarged part I of FIG. 16, and FIG. 16B is a sectional view taken along line JJ in FIG. It is the top view which looked at the sedimentation tank in which 3rd Embodiment of the transfer system was provided from the upper side. It is KK sectional drawing of the sedimentation basin shown in FIG. It is LL sectional drawing of the sedimentation basin shown in FIG. It is a flowchart which shows the flow of a 2nd sludge removal method. It is a figure which shows the modification of the method of support of a space formation member. It is a figure which shows the modification which installed the space formation member 28 shown in FIG. 13 movably in the width direction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The sand basin, which is an embodiment of the present invention, is arranged on the upstream side of the sewage treatment system, and after sedimenting sand contained in sewage or rainwater or other wastewater, the sedimented sand is moved to a sand collecting pit. It is to be removed from dirty water.

  FIG. 1 is a plan view of a sand basin corresponding to one embodiment of the present invention as seen from above, and FIG. 2 is a sectional view of the sand basin shown in FIG.

  As shown in FIG. 1, the sand settling basin 1 is a pond having a rectangular shape in plan view, which includes a dust remover 2, a trough 3, a sand collecting pit 4, and a pump well 5. Hereinafter, the long side direction of the sand basin 1 may be referred to as the longitudinal direction, and the short side direction may be referred to as the width direction. The settling basin 1 shown in FIG. 1 receives sewage from the right side of the figure, and the received water slowly flows toward the left side of the figure (see the straight arrow shown in FIGS. 1 and 2). That is, the longitudinal direction of the sand basin is the direction of water flow, and in FIGS. 1 and 2, the right side of the figures is the upstream side and the left side is the downstream side.

  The dust remover 2 is used to remove contaminants (residuals) mixed in the wastewater that has flowed into the sand basin 1, and is installed upstream of the trough 3. The dust remover 2 has an endless chain 21, a plurality of rakes 22 attached to the endless chain 21 at intervals, and a filter screen 23 submerged in water. The endless chain 21 is provided in a state of standing upright on both sides in the width direction of the sand basin 1, and as shown in FIG. 2, it is wound around the ground side sprocket 211 and the pond bottom sprocket 212. There is. When the endless chain 21 is driven, the rake 22 moves in and out of the water. The filtration screen 23 is arranged on the downstream side of the endless chain 21. The filtration screen 23 is one in which bars extending in the vertical direction are arranged at a predetermined interval (for example, 25 mm to 75 mm), and blocks the passage of contaminants having a size larger than the predetermined interval. The contaminants blocked by the filter screen 23 are scraped up by the rake 22, and the scraped contaminants are placed on a transportation means such as a belt conveyor (not shown) on the ground side.

  On the downstream side of the dust remover 2, a sand collecting pit 4 for collecting the sand accumulated on the bottom 1a of the pond is provided. A sand pump 41 is provided inside the sand collecting pit 4. The sand raising pump 41 is arranged near the bottom surface of the sand collecting pit 4 and conveys the sand collected in the sand collecting pit 4 to the outside of the sand basin 1. A sand lifting pipe 42 is connected to the sand lifting pump 41. The sand sucked by the sand lifting pump 41 is sent to the outside of the sand basin 1 through the sand lifting pipe 42.

  The trough 3 is provided between the sand collecting pit 4 and the pump well 5. That is, the trough 3 is provided downstream of the sand collecting pit 4 and upstream of the pump well 5. The trough 3 is a groove provided at the bottom 1a (see FIG. 2) of the sand basin 1. The pond bottom part 1a is provided with an inclined surface 6 as described later, and a trough 3 is provided so as to be connected to the inclined surface 6. The sand in the wastewater flowing into the sand settling basin 1 sinks toward the basin bottom 1a and accumulates on the basin bottom 1a.

  The pump well 5 is for storing wastewater from which sand has been removed. The pump well 5 is arranged on the most downstream side of the sand basin 1. Further, as shown in FIG. 2, the bottom of the pump well 5 is the deepest part of the sand basin 1. A pumping pump 51 is provided inside the pump well 5. The pumping pump 51 moves the wastewater stored in the pump well 5 to the outside of the sand basin 1. A pumping pipe 52 is connected to the pumping pump 51. The dirty water sucked by the pumping pump 51 is sent to a settling tank (not shown) through the pumping pipe 52. WL shown in FIG. 2 represents the water surface of the sewage. The position of the water surface WL changes depending on the amount of sewage flowing into the sand basin 1 within a range in which the height from the bottom surface of the trough 3 is, for example, 1 m or more and 5 m or less.

  The trough 3 is a groove provided in the center of the sand basin 1 in the width direction as shown in FIG. 1 and extending in a predetermined direction from a position upstream of the pump well 5. That is, it extends toward the sand collecting pit 4. The downstream end of the trough 3 is connected to the sand collecting pit 4, and the sand accumulated on the trough 3 is moved to the sand collecting pit 4 by the flow of water discharged from the discharge port described later.

  The sand basin 1 shown in FIG. 1 also includes a space forming member 8 in the trough 3. The total length of the space forming member 8 is the same as the total length of the trough 3, and the space forming member 8 extends along the trough 3. Detailed description of the space forming member 8 will be described later.

  FIG. 3A is a sectional view taken along line BB in FIG. In FIG. 3A, the lateral direction of the drawing is the width direction of the trough 3.

  FIG. 3A shows a lower portion of the sloped surface 6 provided on the pond bottom 1 a and a trough 3 provided so as to be connected to the sloped surface 6. As shown in FIG. 3A, the inclined surfaces 6 are provided on both sides of the trough 3 in the width direction. The inclined surface 6 is made of concrete and is inclined 45 degrees downward toward the trough 3, and extends in the longitudinal direction between a position upstream of the pump well 5 and the sand collecting pit 4. There is. The inclination angle of the inclined surface 6 may be 30 degrees or 60 degrees, for example.

  Further, as shown in FIG. 3A, the trough 3 is a groove having a sectional shape of 3/4 arc and having a total length of about 15 m. The trough 3 is formed by bending a plate material made of stainless steel or the like, but may be formed of concrete integrally with the inclined surface 6. Further, the cross-sectional shape of the trough 3 is not limited to an arc shape, and may be a U shape, a V shape, or the like. The trough 3 shown in FIG. 3A has a shape in which a cylindrical body having a diameter of about 356 mm is cut out at the upper part (on the liquid surface side) 1/4 and opens upward. Hereinafter, the portion that opens upward will be referred to as the opening 3a of the trough 3. In the space S1 in the trough 3, the upper end portion 3b connected to the upper end opening 3a is narrowed toward the opening 3a. That is, the opening 3a of the trough 3 is an opening narrowed in the width direction orthogonal to the extending direction of the trough.

  The sand contained in the sewage flowing into the sand basin 1 settles at the bottom 1a of the pond in the course of the sewage flowing to the downstream side, but tends to accumulate at the bottom 1a of the upstream side of the sand basin 1. Of the sand that has settled on the bottom 1a of the pond, the sand that settled on the inclined surface 6 further flows down along the inclined surface 6 toward the trough 3, and enters the trough 3 through the opening 3a. Therefore, the sand that has settled on the bottom 1a of the pond is first collected in the trough 3.

  The space forming member 8 shown in FIG. 3A has a cross-sectional shape of 3/4 arc. The space forming member 8 is formed by forming a stainless steel plate material having a plate thickness of 4 mm into an arc-shaped cross section. The space forming member 8 shown in FIG. 3 (a) has a shape in which a lower portion (on the pond bottom side) ¼ of a cylindrical body having a diameter of about 156 mm is cut out, and opens downward. That is, the lower end of the space forming member 8 is opened downward, and the opened portion is hereinafter referred to as the suction port 81. The suction port 81 is an opening having a length L of 80 mm or more in the width direction of the trough 3, and is separated from the inner peripheral wall of the trough 3. The space forming member 8 partitions the space inside the trough 3 and forms a space S2 in which a portion above the lower end is closed. Although the upper end portion 82 of the space forming member 8 is closed, it has an arc shape and is inclined downward. The sand also settles on this space forming member 8, but since it is arcuate, it is difficult for the sand to accumulate, and the sand settling on the space forming member 8 passes along the arcuate side surface 80 and forms the trough 3 It becomes easy to flow down toward the bottom 31 of the. Further, due to the arcuate side surface 80, the lower end portion of the space S2 connected to the suction port 81 becomes narrower as it approaches the suction port 81.

  Here, as shown in FIG. 1 and FIG. 2, the support plate member 91 is bridged in the width direction of the trough 3 at intervals of about 5 m on the upper end of the trough 3. Both ends of the support plate member 91 are fixed to the inclined surface 6, and at the place where the support plate member 91 is installed, the support plate member 91 covers the opening 3a of the trough 3, but the support plate member 91 is provided. The length of the trough extending direction is about 200 mm, and the accumulation of sand on the support plate member 91 does not pose a problem. Moreover, since the length is about 200 mm, the risk that string-like contaminants (for example, hair or vinyl string) will be wrapped around the support plate member 91 is greatly reduced.

  The space forming member 8 shown in FIG. 3A has an upper end portion 82 supported by the support plate member 91. Therefore, the height position of the upper end portion 82 of the space forming member 8 is substantially the same height position as the opening 3 a of the trough 3. In the present embodiment, when viewed in the height (depth) direction, the radial center of the space forming member 8 is displaced upward from the radial center 3c of the trough 3, but When viewed in the width direction, the radial center of the space forming member 8 coincides with the radial center 3c of the trough 3. Therefore, the gap W between the trough 3 and the space forming member 8 is 80 mm or more even at the narrowest position. As described above, the filter member (here, the filter screen 23) is installed on the upstream side, and the gap W between the trough 3 and the space forming member 8 is the maximum length of the contaminant that passes through the filter member (here Then, it is preferable that the mesh width of the screen is longer than 75 mm in order to prevent the contaminants that have passed through the upstream filtering member from clogging the gap W.

  Further, the space S2 in the space forming member 8 is provided with a discharge port 7 for discharging a fluid into the space S2. The discharge port 7 has a long hole shape obtained by flattening the tip of a pipe-shaped water supply pipe 71 having a diameter of less than 50 mm. The maximum opening length of the discharge port 7 in the lateral direction (trough width direction) is about 60 mm. By forming the discharge port 7 into such a flat shape, it is possible to secure a wider range in which the flow velocity is increased, as compared with a perfect circular shape. The water supply pipe 71 penetrates the inclined plate 6 from the inner side of the inclined plate 6, extends along the support plate member 91 in the width direction of the trough 3, and bends downward at the center of the trough 3 in the width direction. Penetrates the support plate member 91 and the space forming member 8 and enters the space S2.

  FIG. 3B is a sectional view taken along line CC of FIG. In FIG. 3B, the left-right direction of the drawing is the extending direction of the trough 3, the right side of the drawing is the upstream side (sand collecting pit 4 side), and the left side is the downstream side (pump well 5 side). Further, the axis 8c of the space forming member 8 passing through the radial center of the space forming member 8 is shown by a one-dot chain line.

  A portion 711 of the water supply pipe 71 that has entered the space S2 extends downward beyond the radial center of the space forming member 8 and is located above the radial center 3c of the trough 3 (see FIG. 3A). It is bent horizontally toward the upstream side (sand pit 4 side). That is, a rectangular winding prevention plate 95 is erected on the upper end of the space forming member 8, and a portion 711 of the water supply pipe 71 that has entered the space S2 has a vertical edge of the winding prevention plate 95. It extends downward along 951 and then extends upstream along a lateral edge 952 of the anti-wrap plate 95. The winding prevention plate 95 prevents the cord-like contaminants from winding around the portion 711 of the water supply pipe 71 that has entered the space S2. The portion of the water supply pipe 71 extending to the upstream side extends beyond the winding prevention plate 95, and the discharge port 7 is located upstream of the winding prevention plate 95.

  The discharge port 7 of the present embodiment is located below the radial center of the space forming member 8 and above the suction port 81. Water is discharged from the discharge port 7 in parallel or substantially parallel to the axis 8c of the space forming member 8. That is, water is discharged in the horizontal direction or the substantially horizontal direction (see the arrow pointing to the right in FIG. 3B).

  The discharge port 7 shown in FIG. 3 is provided on the most upstream side, that is, at the position closest to the sand collecting pit 4.

  When water is discharged from the discharge port 7 into the space 2 of the space forming member 8, a pressure difference is generated between the inside (space S2) and the outside of the space forming member 8 and is accumulated in the trough 3 (space S1). The sand is sucked into the space S2 from the suction port 81 as shown by the curved arrow in FIG. Further, in the space S2 of the space forming member 8, the sucked sand moves toward the sand collecting pit 4 side by the flow of the water discharged from the discharge port 7. As shown in FIG. 3, the suction port 81 is an opening narrowed in the width direction (direction orthogonal to the extending direction of the space forming member 8), and the space S2 is a space expanded from the suction port 81. . Since the suction port 81 is a narrowed opening in this way, the sand that moves in the space S2 is less likely to come out of the space S2, and the sand is prevented from rising. Further, it becomes easier to maintain the flow of water in the space S2, and the sand can be moved further.

  The structure of the discharge port 7 in the support plate member 91 described above is the same in any of the support plate members 91 provided at the upper end of the trough 3. The discharge port 7 is also provided in the downstream end face wall 36 of the trough 3. Hereinafter, the discharge port 7 provided in the downstream end face wall 36 of the trough 3 is referred to as a downstream discharge port, the discharge port 7 in the downstream side support plate member 91 shown in FIGS. 1 and 2 is referred to as an intermediate discharge port, and the upstream side. The discharge port 7 (the discharge port 7 shown in FIG. 3) of the support plate member 91 may be referred to as an upstream discharge port for distinction.

  FIG. 4 (a) is a partial cross-sectional view showing the vicinity of the most upstream end of the trough in an enlarged manner. In FIG. 4A, the right side of the figure is the upstream side, and the left side of the figure is the downstream side.

  As shown in FIG. 4A, a plate-shaped downstream end face wall 36 is attached to the end face which is the most downstream end of the trough 3.

  FIG. 4B is a partial cross-sectional view of FIG. 4A viewed from the right side. That is, FIG. 4B is a view of the downstream end face wall 36 as seen from the upstream side, and the back side of the paper surface is the downstream side.

  FIG. 4B shows the downstream discharge port 7 provided in the downstream end face wall 36. An L-shaped pipe 77 that forms an empty chamber 78 (see FIG. 7A) connected to the downstream discharge port 7 is provided further downstream than the downstream discharge port 7. The L-shaped pipe 77 is an L-shaped pipe in plan view, and is connected to a supply pipe (not shown) for supplying water. The flow direction of the water flowing into the empty chamber 78 changes to the downstream side in the empty chamber 78, and the water is discharged from the downstream discharge port 7 in the horizontal direction or the substantially horizontal direction. The position in the trough width direction where the downstream discharge port 7 is provided is the same position as the position in the trough width direction where the discharge port 7 shown in FIG. 3 is provided. Further, the height position where the downstream discharge port 7 is provided is also the same position as the height position where the discharge port 7 shown in FIG. 3 is provided.

  Although the sand basin 1 of the present embodiment is provided with three outlets 7, a downstream outlet, an intermediate outlet, and an upstream outlet, the discharge flow velocity of water at any of the outlets 7 is 8 m / sec. The above is preferable. If it is less than 8 m / sec, the flow velocity becomes insufficient, and in some cases, the sand cannot be moved a predetermined distance in relation to the water pressure. If the sand cannot be moved by a predetermined distance, a large number of discharge ports are required in the sand movement direction, and the number of pipes to the discharge ports also increases, which is uneconomical because of a large number of devices. Further, the discharge pressure of water at each discharge port 7 is 0.05 MPa or more and 0.3 MPa or less.

  According to the settling basin 1 of the present embodiment described above, it is possible to prevent sand from rising while sufficiently moving the sand.

  Subsequently, a sand removal method for removing the sand accumulated on the bottom 1a of the sand basin 1 of the present embodiment from the sand basin 1 will be described.

  FIG. 5 is a flowchart showing the flow of the sand removing method.

  When the sewage flowing into the sand basin 1 passes through the dust remover 2 shown in FIG. 2, the contaminants (residuals) mixed in the sewage are removed. The sewage that has passed through the dust remover 2 passes through the sand collecting pit 4, reaches the upstream end of the trough 3, and further flows in the extending direction of the trough 3. While the sewage flows through the upstream side portion of the trough 3, most of the sand contained in the sewage settles on the bottom 1a of the sand basin 1. Some sand settles in the sand collecting pit 4, and some settles in the inclined surface 6, and the sand settled in the inclined surface 6 further flows down along the inclined surface 6 toward the trough 3. The sand that has settled to the upper end portion 82 of the space forming member 8 flows along the arc-shaped side surface 80 of the space forming member 8 toward the bottom 31 of the trough 3. Thus, sand is deposited in the space S1 of the trough 3.

  In the sand removing method according to the present embodiment, first, the sand pump 41 shown in FIGS. 1 and 2 is driven to remove the sand in the sand collecting pit 4 from the sand collecting pit 4 before performing the sand collecting step described later. (Step S1). The sand deposited in the sand collecting pit 4 at this stage is mainly the sand in the wastewater that has flowed into the sand basin 1 that has settled in the sand collecting pit 4 and accumulated in the sand collecting pit 4.

  Next, with the sand lifting pump 41 being driven, 1500 liters of water per minute is discharged underwater for 3 minutes from only the upstream discharge port 7 shown in FIG. 3 among the three discharge ports 7 (step S2). . In this step S2, water is discharged from the space S1 of the trough 3 into the space S2 partitioned by the space forming member 8. By discharging water from the upstream discharge port 7 into the space 2, a pressure difference is generated between the inside of the space forming member 8 (the space S2) and the outside, and is accumulated on the upstream side portion of the trough 3 (the space S1). Sand is sucked into the space S2 from the suction port 81 (see the curved arrow in FIG. 3A). Further, in the space S2 of the space forming member 8, the sucked sand moves toward the sand collecting pit 4 by the flow of the water discharged from the upstream discharge port 7. The sand moving in the space S2 of the space forming member 8 is hard to come out of the space forming member 8 in the portion where the pressure difference is generated, and the sand is prevented from rising. Thus, the sand deposited on the upstream side portion of the trough 3 moves in the space S2 of the space forming member 8 and eventually reaches the sand collecting pit 4. The sand that has reached the sand collecting pit 4 is conveyed to the outside of the sand basin 1 by the lift pump 41 that has been driven in step S1 and the sand from the sand basin 1 is removed. The removal of sand here corresponds to an example of this discharging step.

  Then, the discharge of water from the upstream discharge port 7 is stopped, and 1500 liters of water per minute is discharged for 3 minutes underwater from only the intermediate discharge port 7 among the three discharge ports 7 (step S3). . The driving of the sand lifting pump 41 is continued even during the execution of this step S3. In step S3 as well, as in step S2, by discharging water into the space S2 of the space forming member 8, a pressure difference occurs between the inside (space S2) of the space forming member 8 and the outside, and this time, inside the trough 3 The sand accumulated around the intermediate discharge port 7 in the space S1) is sucked again into the space S2 through the suction port 81. Further, the sucked sand moves in the space S2 of the space forming member 8 toward the upstream discharge port 7 shown in FIG. 3 by the flow of water discharged from the intermediate discharge port 7, and reaches the periphery of the upstream discharge port 7. To reach. In the vicinity of the upstream discharge port 7, the momentum of water from the intermediate discharge port 7 decreases, so that the sand that has reached the vicinity of the upstream discharge port 7 drops from the suction port 81 toward the bottom 31 of the trough 3, and once. , Return to the space S1 of the trough 3. That is, sand is deposited around the upstream discharge port 7 in the trough 3 (space S1).

  Next, the discharge of water from the intermediate discharge port 7 is stopped, and 1500 liters of water per minute is discharged from the upstream discharge port 7 shown in FIG. 3 again for 3 minutes under water as in step S2 ( Step S4). By this step S4 as well, the sand accumulated around the upstream discharge port 7 in the trough 3 (space S1) is sucked into the space S2 from the suction port 81, and the sucked sand moves toward the sand collecting pit 4 toward the space. It moves in S2 and eventually reaches the sand collecting pit 4. Even during the execution of step S4, the sand pump 41 continues to be driven, and the sand reaching the sand collecting pit 4 is removed from the sand basin 1 by the sand pump 41. That is, also here, the removal of sand by the lifting sand pump 41, which corresponds to an example of the discharging step, is also performed.

  This time, the discharge of water from the upstream discharge port 7 is stopped, and 1500 liters of water per minute is discharged from the downstream discharge port 7 among the three discharge ports 7 under water for 3 minutes (step S5). The driving of the sand lifting pump 41 is continued even during the execution of this step S5. In step S5 as well, as in steps S2 to S4, by discharging water into the space S2 of the space forming member 8, a pressure difference is generated between the inside (space S2) of the space forming member 8 and the outside (space S2). The sand accumulated around the downstream discharge port 7 in the space S1) is sucked into the space S2 through the suction port 81. Further, the sucked sand moves in the space S2 of the space forming member 8 toward the intermediate discharge port 7 by the flow of the water discharged from the downstream discharge port 7, and reaches the periphery of the intermediate discharge port 7. In the vicinity of the intermediate discharge port 7, the momentum of water from the downstream discharge port 7 decreases, so that the sand reaching the vicinity of the intermediate discharge port 7 descends from the suction port 81 toward the bottom 31 of the trough 3, and the trough 3 Sand is deposited around the intermediate discharge port 7 in the space 3 (space S1).

  Subsequently, the discharge of water from the downstream discharge port 7 is stopped, and 1500 liters of water per minute is discharged from the intermediate discharge port 7 again for 3 minutes under water, similarly to step S3 (step S6). The driving of the sand lifting pump 41 is continued even during the execution of this step S6. Also in step S6, the sand accumulated around the intermediate discharge port 7 in the trough 3 (space S1) is sucked into the space S2 from the suction port 81, and the sucked sand is directed toward the upstream discharge port 7 in the space S2. After moving inside, sand is deposited around the upstream discharge port 7 in the trough 3 (space S1).

  Next, the discharge of water from the intermediate discharge port 7 is stopped, and 1500 liters of water per minute is discharged from the upstream discharge port 7 shown in FIG. 3 for three minutes underwater, as in step S2. (Step S7). By this step S7 as well, the sand accumulated around the upstream discharge port 7 in the trough 3 (space S1) is sucked into the space S2 from the suction port 81, and the sucked sand moves toward the sand collecting pit 4 toward the space. It moves in S2 and eventually reaches the sand collecting pit 4. Even during the execution of step S7, the sand pump 41 continues to be driven, and the sand reaching the sand collecting pit 4 is removed from the sand basin 1 by the sand pump 41. That is, also here, the removal of sand by the lifting sand pump 41, which corresponds to an example of the discharging step, is also performed. Further, the sand lifting pump 41 continues to be driven for a predetermined time even after the discharge of the water from the upstream discharge port 7 is completed, and the sand removal corresponding to an example of the discharging step is continuously performed.

  In this way, the sand contained in the received water is collected in the sand collecting pit 4 after being transferred in the space S2 of the space forming member 8 over six steps. The steps S2 to S7 described above correspond to the sand collecting step. This sand collecting step does not need to be performed after the water in the sand basin 1 is drained and the water in the sand basin 1 is reduced or completely lost, and is performed in a state where the waste water is continuously received in the sand basin. The fluid discharged from the discharge port 7 in the sand collecting step may be the sewage received at the sewage treatment plant, but may be another fluid.

  Then, when the above-described predetermined time has elapsed, the sand lifting pump 41 that has started driving in step S1 is stopped (step S8), and after a predetermined time has elapsed, or when sand has settled to some extent in the sand collecting pit 4 due to the settling sand. , Step S1 is performed again. In this way, steps S1 to S8 are repeatedly performed after the acceptance of waste water is started.

  In the above description, the driving of the sand lifting pump 41 is continued from the start in step S1 to the stop in step S8, but is stopped when the sand in the sand collecting pit 4 decreases to a certain amount. Alternatively, the driving of the sand lifting pump 41 may be stopped during the execution of steps S3 and S5 to S6.

  According to the sand removal method of the present embodiment, it is possible to remove the sand from the sand basin 1 by sufficiently moving the sand in the sand basin 1 while suppressing the rising of the sand. Further, in the sand removing method of the present embodiment, the sand is allowed to flow into the pump well 5 arranged on the most downstream side of the sand basin 1 by setting the sand transfer direction from the downstream side to the upstream side. Is being prevented. That is, in this embodiment, a sand collecting location (sand collecting pit 4 in this embodiment) is provided on the downstream side in the sand transport direction (corresponding to the upstream side of the sand basin 1 in this embodiment), and the sand transport direction upstream side. A wastewater discharge point (pump well 5 in the present embodiment) is provided (corresponding to the downstream side of the sand basin 1 in the present embodiment).

  Next, the sand basin 1 of the second embodiment will be described. In the following description, the components having the same names as those of the components described above will be denoted by the reference numerals used so far, and redundant description may be omitted.

  FIG. 6 is a cross-sectional view of the sand basin of the second embodiment taken along the center in the width direction. Also in FIG. 6, the right side of the figure is the upstream side and the left side is the downstream side.

  The sand basin 1 shown in FIG. 6 is different from the sand basin 1 shown in FIG. 1 in the position where the sand collecting pit 4 is provided. In the sand basin 1 shown in FIG. 6, the upstream trough 3 ′ is provided on the upstream side of the sand collecting pit 4, and the downstream trough 3 ″ is provided on the downstream side of the sand collecting pit 4. Both the upstream side trough 3 ′ and the downstream side trough 3 ″ are shorter troughs than the trough 3 shown in FIG. 1 and the like, and these troughs 3 ′ and 3 ″ are not provided with the support plate member 91. The space forming member 8 (not shown) has the upstream end supported by the upstream end face wall 36 and the downstream end supported by the concrete forming the sand collecting pit 4, so that the space forming member 8 is arranged in the trough 3.

  A dust remover 2 which is the same as the dust remover 2 shown in FIG. 2 is installed further upstream than the upstream trough 3 ', but is not shown in FIG.

  FIG. 7 is a DD sectional view of the sand basin shown in FIG. 6. In FIG. 7, the lateral direction of the drawing is the trough width direction.

  The settling basin 1 of the second embodiment is a pond in which a basin 1a of a basin having a rectangular cross section is repaired to form an inclined surface 6, an upstream trough 3 ', and a downstream trough 3 ". In FIG. 7, the portion of the pond bottom 1a repaired with concrete is shown by cross hatching.

  As shown in FIG. 7, two downstream troughs 3 ″ are arranged in the width direction, and two upstream troughs 3 ′ are also arranged in the width direction. Therefore, in the sand basin 1 of the second embodiment, a total of four troughs are provided. By arranging the troughs side by side in the width direction, the amount of filling the pond bottom part 1a with concrete becomes small when the pond bottom part 1a is repaired, and it is possible to suppress a decrease in the capacity of the sand basin 1 for receiving sewage. A space forming member 8 is provided in each trough.

  Next, a modified example of the sand basin 1 described above will be described.

  FIG. 8 is a perspective view showing a modified example of the space forming member. FIG. 8 is a view showing a state when the space forming member 8 is viewed obliquely from the sand collecting pit 4 side. In FIG. 8, the same components as the support plate member 91, the water supply pipe 71, the winding prevention plate 95, and the discharge port 7 shown in FIG. 3 are shown.

  The space forming member 8 shown in FIG. 8 is a cylindrical pipe member. The space forming member 8 is arranged on the flat pond bottom portion 1a where the trough 3 is not provided, and the lower end 83 of the space forming member 8 is in contact with the pond bottom portion 1a. A plurality of suction ports 81 are arranged in parallel in the extending direction of the space forming member 8 on both sides of the space forming member 8 in the width direction. Each suction port 81 is a vertically long notch in the circumferential surface of a cylindrical pipe, and is provided in the intermediate portion in the vertical direction of the space forming member 8. Each suction port 81 is separated from the pond bottom 1a.

  In addition, the suction port 81 may be a slit-shaped one connected to the extending direction on one side in the width direction of the space forming member 8. Further, the space forming member 8 is not limited to a tubular shape or an arc-shaped cross-sectional shape, but if the upper end portion is closed, the cross-sectional shape is a U-shape, a V-shape, or a U-shape. And so on.

  Further, although the discharge ports 7 of the first embodiment are all flat oblong holes, the present invention is not limited to this shape. Further, the arrangement position of the ejection port 7 is not limited to the position shown in FIG.

  FIG. 9 is a diagram showing a modified example of the ejection port. In FIG. 9, the lateral direction of the drawing is the width direction of the trough 3.

  Each of the discharge ports 7 shown in FIG. 9 has a perfect circle shape. The discharge port 7 shown in FIG. 6A is provided at a position that coincides with the radial center 8c of the space forming member 8. The discharge port 7 shown in FIG. 7B is provided in the inner peripheral wall of the upper end portion 82 of the space forming member 8. Therefore, it is provided above the radial center of the space forming member 8. The discharge ports 7 shown in FIGS. 6B and 6C project horizontally toward the downstream side. The discharge port 7 shown in FIG. 7C is provided at the lower end of the inner peripheral wall of the side surface 80 of the space forming member 8. That is, they are arranged on both sides of the suction port 81. The water supply pipe (not shown) connected to the discharge port 7 shown in FIGS. 2B and 2C is fixed to the inner peripheral wall of the side surface 80 of the space forming member 8 and extends along the inner peripheral wall. The discharge port 7 shown in FIG. 6C also projects toward the downstream side, but the discharge port 7 is installed slightly above and slightly toward the center side.

  Note that the discharge port 7 does not necessarily have to be installed in the space 2 of the space forming member 8 as shown in FIG. 3A and FIG. 9, and is not necessarily provided in the space forming member 8 (suction port 81). What is necessary is just to be installed so as to face downward and obliquely upward and to be able to discharge the fluid into the space 2 of the space forming member 8.

  FIG. 10 is a diagram showing a modification of the method of supporting the space forming member. In FIG. 10A, as in FIG. 3A, the lateral direction of the drawing is the width direction of the trough 3. Further, in FIG. 10B, as in FIG. 3B, the horizontal direction of the drawing is the extension direction of the trough 3, the right side of the drawing is the upstream side (sand collecting pit 4 side), and the left side is the downstream side. Side (pump well 5 side).

  In the space forming member 8 shown in FIG. 3A, the upper end portion 82 is supported by the support plate member 91, but the space forming member 8 shown in FIG. 10A has a suction port 81 (FIG. The lower end 83 on both sides (see FIG. 3) is supported by the support base 92. The support base 92 is made of concrete and is provided on the bottom 31 of the trough 3. The support base 92 is formed on the extending trough 3 at a position where the support plate member 91 is provided. As shown in FIG. 9B, the support base 92 has an upstream side inclined surface 921 and a downstream side inclined surface 922, and a support portion 923 between the upstream side inclined surface 921 and the downstream side inclined surface 922. The lower end 83 of the space forming member 8 is supported by this support portion 923. As shown in FIG. 9A, a horizontal plane 9231 is provided at the center of the support portion 923 in the width direction, and both sides of the horizontal plane 9231 are inclined downward toward the trough 3. Further, as shown in (b) of the figure, the water supply pipe 71 extends upward from below the support portion 923, and the water supply pipe 71 penetrates the horizontal plane 9231 and at the same time bends to the upstream side so as to be placed on the horizontal plane 9231. The discharge port 7 facing the upstream side is formed in the. As shown in FIG. 4A, this discharge port 7 also has a flat elongated hole shape.

  The shape and size of the space forming member 8 shown in FIG. 10 (a) are the same as the shape and size of the space forming member 8 shown in FIG. 3 (a), and have a sectional shape of 3/4 arc. is there. The radial center 8c of the space forming member 8 whose lower end 83 is supported by the support base 92 coincides with the radial center 3c of the trough 3.

  Further, in the modification shown in FIG. 10, the discharge port 7 is located below the radial center 3c of the trough 3. Further, the upper end portion 82 of the space forming member 8 is located below the opening 3 a of the trough 3.

  Although the upper end portion 82 of the space forming member 8 may be located above the opening 3a of the trough 3, the sand accumulated in the space S1 in the trough 3 can be efficiently stored in the space S2 of the space forming member 8. In order to suck in well, the suction port 81 needs to be located below the opening 3a of the trough 3.

  Further, as shown in FIG. 8, the trough 3 may not be provided in the pond bottom portion 1a, and the pond bottom portion 1a may be a flat surface, and the space forming member 8 may be movably installed in the pond width direction. By doing so, every time the space forming member 8 is slid in the pond width direction, water can be ejected from the ejection port 7 and the sand can be transferred to the downstream side over a wide area in the width direction.

  Next, the sedimentation tank provided with the transfer system will be described. The sedimentation basin is located on the downstream side of the sand basin in the sewage treatment system, receives the wastewater from which sand has been removed by the sand basin, sediments the sludge contained in the received wastewater, and then the sedimented sludge is placed in the sludge pit. It removes it from the sewage by moving it to.

  11 is a plan view of the settling tank provided with the transfer system as seen from above, and FIG. 12 is a side sectional view of the settling tank shown in FIG.

  As shown in FIG. 11, the sedimentation basin 10 is a basin having a sludge pit 14 and having a rectangular shape in plan view. Hereinafter, the long side direction of the settling tank 10 may be referred to as the long side direction, and the short side direction may be referred to as the width direction. The settling basin 10 shown in FIGS. 11 and 12 receives sewage from a water conduit 10b provided on the right side of the figure (see FIG. 12), and the received water is directed to the left side of the figure, for example, 0.03 m / min. It slowly flows at a flow rate of about 0.5 m / min (see the straight line arrows shown in FIGS. 11 and 12). That is, the longitudinal direction of the sedimentation tank is the direction of water flow, and in FIGS. 11 and 12, the right side of the figures is the upstream side and the left side is the downstream side. The water that has flowed to the downstream side of the settling tank 10 is discharged from an overflow weir (not shown) and sent to, for example, a reaction tank or the like of the sewage treatment system. The bottom surface 100a of the pond bottom 10a is slightly inclined so that the water depth of the settling basin 10 increases toward the upstream side.

  A sludge pit 14 for collecting the sludge accumulated on the pond bottom 10a is provided on the downstream side of the water conduit 10b. A sludge pump (not shown) is provided outside the sludge pit 14, and a suction pipe (not shown) of the sludge pump is provided in the sludge pit 14. The sludge collected in the sludge pit 14 is sucked from the suction pipe by driving the sludge pump, and is transported to the outside of the sedimentation basin 10.

  The pond bottom 10a has a length of about 7 m in the longitudinal direction, and the pond bottom 10a is provided with a plurality of flow paths extending along the longitudinal direction. The flow path will be described with reference to FIG.

  FIG. 13 is a sectional view taken along line EE in FIG. In FIG. 13, the lateral direction of the drawing is the width direction of the settling tank 10.

  As shown in FIG. 13, on the bottom surface 100a of the pond bottom portion 10a, a plurality of flow path forming members 13 are arranged at predetermined intervals in the width direction. Each of these flow path forming members 13 has a pair of inclined pieces 13a connected to each other at a substantially right angle, and has an angled shape in which a corner portion 13b is formed at a connecting portion of the inclined pieces 13a. The flow path forming member 13 is fixed to the bottom surface 100a at the tip end of each inclined piece 13a with the corner 13b facing upward. As shown in FIGS. 12 and 13, these flow path forming members 13 extend in the entire longitudinal direction of the pond bottom 10a. Further, as shown in FIG. 13, an inclined portion 100c inclined inward in the width direction is formed at the lower end portions of the pair of side walls 10c in the settling tank 10.

  In the settling tank 10 of the present embodiment, five flow paths F are provided. Of these five flow paths F, the two flow paths F provided on both sides in the width direction of the sedimentation tank 10 are defined by the inclined portion 100c of the side wall 10c, the bottom surface 100a, and the inclined piece 13a of the flow path forming member 13. Also, the space above is open. Further, the three flow passages F on the center side in the width direction are spaces which are defined by the inclined pieces 13a of the adjacent flow passage forming members 13 and the bottom surface 100a, and which are open upward. The sludge in the wastewater that has flowed into the settling basin 10 settles toward the bottom 10a of the pond, enters the flow path F, and flows down along the sloped portion 100c of the side wall 10c and the sloped piece 13a of the flow path forming member 13. As a result, the settled sludge is deposited on the bottom surface 100a in the channel F. The sludge settled at the corners 13b of the flow path forming member 13 also flows down to the bottom surface 100a after connecting any of the inclined pieces 13a. Here, the inclination angle of the inclined portion 100c of the side wall 10c and the inclined piece 13a of the flow path forming member 13 is not particularly limited, but in the settling tank 10 of the present embodiment, both are set to 45 degrees. There is. The flow path forming member 13 is made of metal such as stainless steel, but may be made of concrete integrally with the bottom surface 100a. Further, the inclined piece 13a of the flow path forming member 13 and the inclined portion 100c of the side wall 10c may have an arcuate cross-sectional shape. The sludge accumulated on the bottom surface 100a in the flow path F is moved to the sludge pit 14 by the flow of water discharged from the discharge port described later.

  A transfer system 20 is provided in the settling tank 10 shown in FIGS. 11 to 13. The transfer system 20 discharges the space supply member 28, the support member 29 that supports the space formation member 28, the mounting frame 26 on which the support member 29 is suspended, the water supply pipe 271, and the water supplied by the water supply pipe 271. And a discharge port 27 for

  As shown in FIG. 13, the space forming member 28 is arranged on the bottom surface 100a at the center in the width direction in each flow path F and in a state of being separated from the bottom surface 100a. Further, as shown in FIGS. 11 and 12, the space forming member 28 extends along the longitudinal direction of the settling basin 10, and the total length of the space forming member 28 is equal to the length of the pond bottom portion 10a in the longitudinal direction. Is the same. The water supply pipe 271 corresponds to an example of a fluid supply pipe, one end side thereof is connected to a water supply source not shown, and the other end side thereof is connected to a downstream side portion of the space forming member 28 as shown in FIG. ing.

  The mounting frame 26 has a U-shaped cross section and, as shown in FIGS. 11 and 13, extends over the pair of side walls 10c while extending in the width direction. Further, as shown in FIGS. 11 and 12, a plurality of mounting frames 26 are provided at a predetermined interval in the longitudinal direction. As shown in FIG. 13, a plurality of support members 29 are provided in a position corresponding to the space forming member 28 in the width direction and extend in the vertical direction. Further, as shown in FIG. 12, a plurality of support members 29 are provided at positions corresponding to the positions of the mounting frame 26 in the longitudinal direction with a predetermined interval in the longitudinal direction. As shown in FIG. 13, these support members 29 are attached to a pipe member 291 extending in the vertical direction, a lower screw member 292 attached to the lower end of the pipe member 291, and an upper end of the pipe member 291. It has an upper screw member 293. Further, these support members 29 support the space forming member 28 by attaching the lower screw member 292 to the space forming member 28 and the upper screw member 293 to the mounting frame 26.

  FIG. 14A is an enlarged view showing an enlarged part G of FIG. In FIG. 14A, the left-right direction of the drawing is the width direction of the settling tank 10.

  The space forming member 28 shown in FIG. 14A has substantially the same cross-sectional shape as the space forming member 8 shown in FIG. 3, and the lower end of the space forming member 28 opens downward. Hereinafter, this open portion will be referred to as a suction port 281. The suction port 281 is an opening having a length L of 80 mm or more in the width direction and is separated from the bottom surface 100a. The space forming member 28 partitions the inside of the flow path F and forms a space S3 in which a portion above the lower end is closed. The upper end portion 282 of the space forming member 28 is closed, and the lower end portion of the space S3 that is connected to the suction port 281 is narrowed toward the suction port 281 due to the arcuate side surface 280. The upper end portion 282 of the space forming member 28 is provided with a tubular portion 283 having a thread groove corresponding to the lower screw member 292 of the support member 29 on the inner circumference. Here, the lower screw member 292 is one in which the lower portion is threaded and the upper portion is unthreaded. This upper portion is inserted into the pipe member 291, and the pipe member 291 is welded or the like. It is fixed to. The space forming member 28 is supported by the support member 29 by screwing the lower screw member 292 into the tubular portion 283.

  FIG. 14B is an enlarged view showing the portion H of FIG. 13 in an enlarged manner. Also in FIG. 14B, the lateral direction of the drawing is the width direction of the settling tank 10.

  As shown in FIG. 14 (b), the upper screw member 293 is such that the upper portion is threaded and the lower portion is not threaded, and this lower portion is inserted into the pipe member 291. And is fixed to the pipe member 291 by welding or the like. While the upper screw member 293 is inserted into the hole formed in the mounting frame 26, the support member 29 is suspended from the mounting frame 26 by tightening the nuts N from above and below the mounting frame 26, respectively. . The support member 29 can adjust the vertical position by adjusting the position of the nut N in the upper screw member 293. Thereby, the vertical position of the space forming member 28 supported by the supporting member 29 can be adjusted, and the distance between the suction port 281 and the bottom surface 100a can be changed. Further, even when wastewater is accumulated in the settling basin 10, by removing the support member 29 from the mounting frame 26 and pulling up the removed support member 29, the space forming member 28 and the discharge port 27 described later are also pulled up. be able to. As a result, maintenance of the space forming member 28 and the discharge port 27 can be performed even when wastewater is accumulated in the sedimentation basin 10.

  Further, as shown in FIG. 14A, the space S3 in the space forming member 28 is provided with a discharge port 27 for discharging a fluid into the space S3. The discharge port 27 has the same structure as the discharge port 7 shown in FIG. As described above with reference to FIG. 12, the water supply pipe 271 extending downward to the downstream side portion of the space forming member 28 penetrates the space forming member 28, and as shown in FIG. It has entered S3. The portion 2711 of the water supply pipe 271 that has entered the space S3 is located below the radial center of the space forming member 28, like the portion 711 of the water supply pipe 71 that has entered the space S2 shown in FIG. And bends horizontally toward the upstream side (front side in the figure). In this embodiment, the winding prevention plate 95 shown in FIG. 3 is not provided. The reason for this is that the string-like contaminants are removed in the sand basin, and the wastewater received by the settling basin 10 contains almost no string-like contaminants, so it is necessary to prevent such string-like contaminants from wrapping around. This is because there is little nature.

  The discharge port 27 of the present embodiment is provided at the end portion on the downstream side in the longitudinal direction in the space S3, is below the radial center of the space forming member 28, and is less than the suction port 281. It is located above. Water is discharged from the discharge port 27 toward the upstream side in parallel or substantially parallel to the axis of the space forming member 28. That is, water is discharged horizontally or substantially horizontally toward the upstream side, and in FIGS. 11 and 12, the right side of the drawings is the downstream side in the discharging direction, and the left side of the figures is the upstream side in the discharging direction.

  By discharging water from the discharge port 27 into the space S3 of the space forming member 28, a pressure difference is generated between the inside (the space S3) of the space forming member 28 and the outside, and is accumulated on the bottom surface 100a in the flow path F. The sludge thus formed is sucked into the space S3 through the suction port 281 as indicated by the curved arrow in FIG. Further, in the space S3 of the space forming member 28, the sucked sludge moves toward the downstream side (sludge pit 14 side) in the discharge direction due to the flow of the water discharged from the discharge port 27. As shown in FIG. 14A, since the suction port 281 is a narrowed opening, sludge that moves in the space S3 is less likely to come out of the space S3, and the sludge scattering is further suppressed. .

  Since the sludge has a particle size smaller than that of sand and is easier to move than sand, the sludge can be sufficiently moved at a discharge flow velocity slower than the discharge flow velocity of water at the discharge port 7 shown in FIG. . Therefore, the discharge flow velocity at the discharge port 27 of the present embodiment can be set to, for example, about 1/3 of the discharge flow velocity of water at the discharge port 7 shown in FIG. Further, the amount of water discharged from the discharge port 27 can be set to about 1/3 of the amount of water discharged from the discharge port 7 shown in FIG. 3, for example, discharged from the discharge port 27. The amount of water discharged can be set to about 500 liters per minute.

  According to the transfer system 20 of the present embodiment described above, the sludge can be prevented from rising while being sufficiently moved.

  Next, a sludge removing method for removing the sludge accumulated on the bottom 10a of the settling tank 10 of the present embodiment from the settling tank 10 will be described. This sludge removal method corresponds to an example of a contaminant removal method.

  FIG. 15 is a flowchart showing the flow of the sludge removing method.

  The sewage that has flowed into the settling basin 10 reaches the upstream end of the flow path F through the sludge pit 14 and further flows in the extending direction of the flow path F. While the wastewater flows in the extending direction of the flow path F, the sludge contained in the wastewater settles in the sludge pit 14 and the pond bottom 10a. The sludge settled on the inclined portion 100c of the side wall and the flow path forming member 13 in the flow path F flows down toward the bottom surface 100a. In this way, sludge is deposited on the bottom surface 100a in the channel F.

  In the sludge removing method according to the present embodiment, first, a sludge pump (not shown) provided in the sludge pit 14 is driven to remove the sludge in the sludge pit 14 from the sludge pit 14 (step S1). The sludge accumulated in the sludge pit 14 at this stage is mainly the sludge that has settled in the sludge pit 14 and accumulated in the sludge pit 14 among the sludge in the wastewater flowing into the sedimentation basin 10.

  Next, while the sludge pump is being driven, 500 liters of water per minute is discharged from the discharge port 27 under water for 3 minutes (step S2). In this step S2, water is discharged from the flow path F into the space S3 partitioned by the space forming member 28. Since water is discharged from the discharge port 27 into the space S3, a pressure difference is generated between the inside (space S3) and the outside of the space forming member 28, and the sludge accumulated on the bottom surface 100a in the flow path F is sucked in. It is sucked into the space S3 through the mouth 281 (see the curved arrow shown in FIG. 14A). Further, in the space S3 of the space forming member 28, the sucked sludge moves toward the downstream side (sludge pit 14 side) in the discharge direction due to the flow of the water discharged from the discharge port 27. The sludge moving in the space S3 of the space forming member 28 is less likely to go out of the space forming member 28 in the portion where the pressure difference is generated, and the sludge is prevented from rising. Thus, the sludge deposited on the bottom surface 100a in the flow path F moves in the space S3 of the space forming member 28 and eventually reaches the sludge pit 14. The movement of the sludge here corresponds to an example of the movement process. This moving step does not need to be performed after draining the water in the settling tank 10 to reduce the water in the settling tank 10 or when all the water in the settling tank 10 has been completely removed, and is performed in a state where the wastewater is continuously received in the settling tank. The sludge that has reached the sludge pit 14 is transported to the outside of the settling tank 10 by the sludge pump started to be driven in step S1 and the sludge is removed from the settling tank 10. The removal of sludge here corresponds to an example of a discharge process.

  Then, when the discharge of water from the discharge port 27 is finished and a predetermined time has elapsed thereafter, the sludge pump started to be driven in step S1 is stopped (step S3). Further, when a predetermined time further elapses, or when sludge has settled to some extent in the sludge pit 14 due to the sludge that has settled, step S1 is performed again. In this way, steps S1 to S3 are repeatedly performed after the acceptance of waste water is started.

  According to the sludge removal method of the present embodiment, sludge can be sufficiently moved in the settling tank 10 while suppressing the sludge from rising, and the sludge can be removed from the settling tank.

  Next, a sedimentation tank provided with the second embodiment of the transfer system will be described. In the following description, the components having the same names as those of the components described above will be denoted by the reference numerals used so far, and redundant description may be omitted.

  FIG. 16 is a sectional view showing a mode corresponding to FIG. 13 in a sedimentation tank provided with the transfer system of the second embodiment. In FIG. 16, the lateral direction of the drawing is the width direction of the settling tank 10.

  The transfer system 20 provided in the settling tank 10 shown in FIG. 16 includes a space forming member 28 that is a part of the trough 33, a discharge port 27 provided in the space forming member 28, and a water supply pipe 271. There is. The troughs 33 are provided on the downstream side of the sludge pit 14 shown in FIG. 11 and extend in the longitudinal direction of the pond bottom portion 10a, and a plurality of troughs 33 are provided at a predetermined interval in the width direction. The trough 33 has a groove forming body 331 that forms a groove, a space forming member 28, and a discharge port 27. A water supply pipe 271 that extends in the vertical direction from the outside of the settling basin 10 toward the basin bottom 10 a is connected to the discharge port 27. Further, on the pond bottom portion 10a, inclined surfaces 16 that are inclined downward toward the trough 33 and are connected to the trough 33 from both sides in the width direction of the trough 33 are formed of concrete. The inclined surface 16 extends in the longitudinal direction of the pond bottom 10a. In FIG. 16, the portion of the pond bottom 10a formed of concrete is shown by cross hatching.

  FIG. 17A is an enlarged view showing the I portion of FIG. 16 in an enlarged manner. In FIG. 17A, the lateral direction of the drawing is the width direction.

  As shown in FIG. 17A, the trough 33 has a first arc-shaped member 33a and a second arc-shaped member 33b each having a 5/8 arc cross-sectional shape. The first arc-shaped member 33a and the second arc-shaped member 33b are formed by cutting a part of a pipe material such as stainless steel. The first arc-shaped member 33a is a portion (3/8) from 9 o'clock to 1 o'clock between 9 o'clock and a short hand of a clock in a pipe material having a thickness of about 3 to 4 mm and a diameter of about 250 mm. Arc) is a cutout. Further, the second arc-shaped member 33b is a portion (3/4) between 4 o'clock and 5 o'clock and 9 o'clock in the pipe material having a thickness of about 3 to 4 mm and a diameter of about 150 mm, which is pointed by the hour hand of the timepiece. 8 arcs) are cut out. The trough 33 is formed by abutting and joining the end of the second arc-shaped member 33b corresponding to 9 o'clock to the end of the second arc-shaped member 33a corresponding to 9 o'clock. The space forming member 28 and the groove forming body 331 are formed by the first arc-shaped member 33a and the second arc-shaped member 33b. The space forming member 28 is open downward. The portion that opens downward serves as the suction port 281 of the space forming member 28. The suction port 281 is an opening having a length L of 80 mm or more in the width direction, and is separated from the bottom 331a of the groove forming body 331. The bottom 331a of the groove forming body 331 corresponds to an example of the bottom portion. The upper end portion 282 of the space forming member 28 is closed in an arc shape and is inclined downward. The space forming member 28 forms a space S3 in which a portion above the lower end is closed. The lower end portion of the space S3 that is connected to the suction port 281 becomes narrower as it approaches the suction port 281.

  Further, the groove forming body 331 is open upward. Hereinafter, the left half of the groove forming body 331 in the width direction shown in FIG. 17A will be referred to as one end side of the groove forming body 331, and the right half of the groove forming body 331 in the width direction will be referred to as the other side of the groove forming body 331. It is called the end side. The space forming member 28 is connected to one end side of the groove forming body 331 via a common portion in a state of being separated from the other end side of the groove forming body 331. As a result, the space between the other end of the groove forming body 331 and the space forming member 28 opens upward. Hereinafter, the portion that opens upward is referred to as the opening 334 of the trough 33. Further, the space in the groove forming body 331 excluding the space S3 of the space forming member 28 is referred to as a space S4. That is, the combined space of the spaces S3 and S4 corresponds to the groove, and the opening 334 of the trough 33 corresponds to the opening of the groove. The space forming member 28 in the present embodiment is provided in the groove, and the suction port 281 is located below the opening of the groove.

  As described above, since the space forming member 28 is connected to one end side in a state of being separated from the other end side of the groove forming body 331, a member that supports the space forming member 28 can be omitted. As a result, the sludge settling in the groove is not obstructed by the member supporting the space forming member 28 over the entire length of the trough 3.

  Further, as described above, the trough 3 of the present embodiment is formed by joining the first arc-shaped member 33a having a diameter of about 250 mm and the second arc-shaped member 33b having a diameter of about 150 mm. Therefore, the gap W between the space forming member 28 and the other end side of the groove forming body 331 is secured to be about 100 mm over the entire length of the trough 33. Further, since the space forming member 28 and the groove forming body 331 have a common part, which is partly common to each other, it is easy to secure the gap W, and as a result, the size of the trough 33 in the width direction is suppressed. You can

  The sludge contained in the sewage that has flowed into the settling basin 10 settles on the pond bottom 10a in the course of the sewage flowing to the downstream side, and the sludge that settled on the inclined surface 16 is further along the inclined surface 16. It flows down to the trough 33. The sludge that has flowed down from the inclined surface 16 on the right side in FIG. 17A enters the groove through the opening 3334 of the trough 33. In addition, the sludge that has flowed down from the inclined surface 16 on the left side of FIG. 17A passes through the arc-shaped side surface of the space forming member 28 and enters the groove from the opening 334 of the trough 33. As a result, the sludge settled on the pond bottom 10a is collected at the bottom of the groove.

  FIG. 17B is a sectional view taken along the line JJ in FIG. In FIG. 17B, the left-right direction of the drawing is the extending direction of the trough 33, the right side of the drawing is the upstream side (sludge pit 14 side), and the left side is the downstream side.

  As shown in FIGS. 17A and 17B, in the water supply pipe 271 extending downward to the space forming member 28, the lower end portion penetrates the upper end portion 282 of the space forming member 28, and the space forming member 28. It communicates with the space S3. Further, in the space S3 of the space forming member 28, a discharge port 27 that discharges a fluid into the space S3 is provided in a region where the water supply pipe 271 communicates. The discharge port 27 is formed by partitioning the upper part of the space S3 in the space forming member 28 with a partition member 272. The partition member 272 has a horizontal portion 2721 that extends horizontally in the extending direction of the trough 33, and an inclined portion 2722 that is inclined upward from the downstream end of the horizontal portion 2721. The horizontal portion 2721 is connected to both sides of the inner peripheral surface of the space forming member 28 in the width direction across the upper end, and the upstream side (sludge pit 14 side) end thereof is upstream of the lower end portion of the water supply pipe 271. Located on the side. The downstream end of the inclined portion 2722 is connected to the downstream side of the inner peripheral surface of the space forming member 28 to which the lower end portion of the water supply pipe 271 is connected, and the downstream side of the discharge port 27 is connected. It is blocked. With these, the region in the space S3 of the space forming member 28 where the water supply pipe 271 communicates is partitioned by the partition member 272. The discharge port 27 of this embodiment may have the same structure as the discharge port 27 shown in FIG.

  From the discharge port 27, the water supplied from the water supply pipe 271 is discharged in the horizontal direction or the substantially horizontal direction toward the upstream side (see the arrow pointing to the right in FIG. 17B). That is, in FIG. 17B, the right side of the drawing is the downstream side in the ejection direction, and the left side of the drawing is the upstream side in the ejection direction. When water is discharged from the discharge port 27 into the space S3 of the space forming member 28, a pressure difference is generated between the inside (space S3) and the outside (space S4) of the space forming member 28 and is deposited on the bottom of the groove. The sludge is sucked into the space S3 through the suction port 281 as indicated by the curved arrow in FIG. Further, in the space S3 of the space forming member 28, the sucked sludge moves toward the downstream side (sludge pit 14 side) in the discharge direction due to the flow of the water discharged from the discharge port 27. As shown in FIG. 17A, since the suction port 281 is an opening narrowed in the width direction, it is difficult for the sand moving in the space S2 to come out of the space S3, and the sludge is sprinkled. Can be suppressed more.

That is, the settling basin provided with the transfer system of the second embodiment is a settling basin in which the sludge contained in the received water settles in the groove provided at the bottom of the basin,
A space forming member which forms a space whose upper end portion is closed, and which is provided with a suction opening below the upper end portion and spaced from the bottom of the groove
A discharge port for discharging a fluid into the space,
The suction port functions as an opening for sucking sludge accumulated in the groove into the space by discharging a fluid from the discharge port,
The space forming member functions as a path in which sludge sucked into the space moves toward the downstream side in the discharge direction of the fluid when the fluid is discharged from the discharge port,
The pond bottom has a groove forming body that forms the groove,
The space forming member, of the groove forming body, of the one end side and the other end side in the width direction orthogonal to the extending direction of the groove, is connected to the one end side in a state of being separated from the other end side, It is provided along the extending direction of the groove.

Further, the space forming member is provided in the groove,
The suction port may be located below the opening of the groove.

  Furthermore, a part of the space forming member may be common to a part of the groove forming body.

  The space forming member may have a curved upper surface.

Furthermore, the pond bottom portion has a pair of inclined surfaces that are inclined downward toward the groove on both sides in the width direction of the groove,
One of the pair of inclined surfaces has a lower end portion connected to the other end side of the groove forming body,
The other end of the pair of inclined surfaces may have a lower end portion connected to the upper end portion of the space forming member.

  Further, the space forming member may be connected to the one end side over substantially the entire length of the groove.

  Next, a sedimentation tank provided with the third embodiment of the transfer system will be described.

  FIG. 18 is a plan view of the settling tank provided with the third embodiment of the transfer system as seen from above. In FIG. 18, the horizontal direction of the drawing is the longitudinal direction of the sedimentation tank 10, and the vertical direction of the drawing is the width direction of the sedimentation tank 10. FIG. 19 is a cross-sectional view of the sedimentation tank shown in FIG. 18, taken along the line K-K. In FIG. 19, the left-right direction of the drawing is the longitudinal direction of the sedimentation tank 10. 20 is a sectional view of the sedimentation tank shown in FIG. 18, taken along the line L-L. In FIG. 20, the lateral direction of the drawing is the width direction of the sedimentation tank 10.

  In the settling tank 10 shown in FIGS. 18 to 20, the longitudinal direction is the direction of water flow, and in FIGS. 18 and 19, the right side of the drawings is the upstream side and the left side is the downstream side. The settling tank 10 includes a pair of side walls 10c extending in the longitudinal direction (see FIG. 18), an upstream wall 10h extending in the width direction and located on the upstream side, and a sidewall extending in the width direction and located on the downstream side. It is a pond that has a downstream wall 10 g, a length in the longitudinal direction of about 35 m, and a length in the width direction of about 25 m and has a rectangular shape in plan view. As shown in FIG. 19, a weir 100g for overflow is provided on the downstream wall 10g. The sewage that has passed over the weir 100 g is sent to, for example, a reaction tank of the sewage treatment system. Further, as shown in FIG. 18, the upstream wall 10h is provided with an opening 100h communicating with a water conduit (not shown). It should be noted that each of the pair of side walls 10c and the upstream wall 10h is provided with a plurality of pillar portions at predetermined intervals in the extending direction thereof.

  As shown in FIGS. 18 and 20, a sludge pit 14 is provided in the center portion in the width direction on the upstream side of the sedimentation tank 10. A sludge pump (not shown) is provided outside the sludge pit 14, and a suction pipe (not shown) of the sludge pump is provided in the sludge pit 14. Further, as shown in FIGS. 18 and 20, a pair of accumulation grooves 141 extending in the width direction and connected to the sludge pit 14 are provided on both sides of the sludge pit 14 in the width direction. Each of these accumulation grooves 141 is a groove having a width of about 4 m in the longitudinal direction of the settling tank 10 and a total length of itself of about 10 m in the width direction of the settling tank 10. . These accumulation grooves 141 correspond to an example of a transfer path, and the groove bottom surface 141a of the accumulation groove 141 corresponds to an example of a groove bottom portion of the transfer path. Note that, as shown in FIG. 20, the groove bottom surface 141 a of each of the accumulation grooves 141 is inclined so that the water depth of the sedimentation basin 10 increases toward the sludge pit 14.

  As shown in FIG. 18, in the settling tank 10, the upstream side of the sludge pit 14 and the accumulation groove 141 is divided into four regions by three partition walls 10 d extending in the longitudinal direction, and each region is divided into four regions. A pond bottom 10a is provided. Similar to the side wall 10c, the partition wall 10d is provided with pillar portions at predetermined intervals in the longitudinal direction, and the lower end portion of the partition wall 10d where the pillar portion is not provided has a haunch shape. The cross-sectional shape is large. Further, a beam 10e (see FIG. 19) extending in the width direction is provided between the pillar portions of the adjacent partition walls 10d. Further, a beam extending in the width direction is also provided between the pillar portion of the side wall 10c and the pillar portion of the partition wall 10d. Beams are omitted in FIGS. 18 and 20 to simplify the drawings. Further, as shown in FIGS. 19 and 20, a ceiling 10f is provided on the upstream side of the pond bottom 10a and above the sludge pit 14 and the accumulation groove 14. In FIG. 18, the ceiling 10f is omitted to show the accumulation groove 14.

  On the bottom surface 100a of each of the pond bottom portions 10a shown in FIG. 19, a flow passage forming member 13 having the same cross-sectional shape as the flow passage forming member 13 shown in FIGS. 11 to 13 is formed in the longitudinal direction of the bottom surface 100a of the pond bottom portion 10a. It is arranged so as to extend over the entire length. The lower end portion of the side wall 10c of this embodiment is not provided with the inclined portion 100c shown in FIG. 13, and the lower end portion of the partition wall 10d is not provided with the inclined portion. In the present embodiment, the second flow path forming member 131 formed of one inclined piece is arranged at both end portions in the width direction of the bottom surface 100a of the pond bottom portion 10a. In the present embodiment, as shown in FIG. 20, by the flow passage forming member 13 and the second flow passage forming member 131, four regions are provided in each of the four regions partitioned by the partition wall 10d in the pond bottom portion 10a. The two flow paths F are formed side by side in the width direction. The second flow path forming member 131 may be omitted by providing an inclined portion at the lower end portion of the side wall 10c or the partition wall 10d.

  A transfer system 20 is provided in each area of the settling tank 10 partitioned by the partition wall 10d. The transfer system 20 includes a space forming member 28, a support member 29, a mounting frame 26, a water supply pipe 271, and a discharge port 27, like the transfer system 20 shown in FIGS. 11 to 14. The space forming member 28 has the same sectional shape as that of the space forming member 28 shown in FIG. 14, and is arranged in each of the flow paths F in a state of extending over substantially the entire length of the flow path F in the longitudinal direction. These space forming members 28 are supported by the supporting member 29 and the mounting frame 26 shown in FIGS. 11 to 13 in the same configuration as the supporting member 29 and the mounting frame 26 in a state of being separated from the bottom surface 100a of the pond bottom portion 10a. There is. The mounting frame 26 extends in the width direction of the settling tank 10 in each of the regions of the settling tank 10 partitioned by the partition wall 10d, and the mounting frame 26 is spaced in the longitudinal direction of the settling tank 10. There are multiple open spaces. Both ends of the mounting frame 26 are supported by the receiving frames 261. These receiving frames 261 are fixed to portions of the side wall 10c and the partition wall 10d that are above the water surface. A supporting member 29 is suspended from the mounting frame 26 supported by each of the receiving frames 261.

  As shown in FIG. 19, a plurality of water supply pipes 271 of this embodiment are connected to the upper end portion of the space forming member 28 at intervals of about 6 m in the longitudinal direction. Similar to the water supply pipe 271 shown in FIG. 14, these water supply pipes 271 penetrate the space forming member 28, enter the space forming member 28, and then bend to the upstream side (sludge pit 14 and accumulation groove 141 side). The same outlet as the outlet 27 shown in FIG. 14 is formed. Thereby, in this embodiment, five discharge ports are provided in each space forming member 28 at intervals of about 6 m in the longitudinal direction. From these discharge ports, the water supplied from the water supply pipe 271 is discharged in the horizontal direction or the substantially horizontal direction toward the upstream side (the right side in FIGS. 18 and 19). That is, in FIGS. 18 and 19, the right side of the drawing is the downstream side in the ejection direction, and the left side of the drawing is the upstream side in the ejection direction. Hereinafter, among the five discharge ports formed in each space forming member 28, the discharge port on the most downstream side in the discharge direction (the most upstream side in the settling tank 10) may be referred to as a first discharge port. It may be referred to as a second ejection port, a third ejection port, a fourth ejection port, and a fifth ejection port, respectively, in the order provided from the first ejection port toward the upstream side in the ejection direction (downstream side in the sedimentation tank 10). is there. When viewed from the settling tank 10 shown in FIGS. 18 and 19, the first discharge port is provided on the most upstream side of the water flow in the settling tank 10, and the fifth discharge port is the water in the settling tank 10. Will be provided at the most downstream side of the flow. 18 and 20, the water supply pipe 271 is omitted in order to simplify the drawings.

  As shown in FIGS. 18 and 19, on the groove bottom surface 141a of each of the pair of accumulation grooves 141, the flow path forming member 13 and the second flow path forming member 131 ′ extending in the width direction of the settling tank 10 are settled. A plurality of flow channels F ′ are formed at intervals in the longitudinal direction of the pond 10 and extend over substantially the entire length of the accumulation groove 141. In the present embodiment, three flow paths F ′ are formed in each of the pair of accumulation grooves 141 that sandwich the sludge pit 14. A second transfer system 20 'is provided in each of the pair of accumulation grooves 141. Like the transfer system 20, the second transfer system 20 ′ includes a space forming member 28, a support member 29, a mounting frame 26, a water supply pipe 271, and a discharge port. The space forming member 28 has the same sectional shape as that of the space forming member 28 shown in FIG. 14, and is arranged in each of the flow paths F ′ in a state of extending over substantially the entire length of the flow path F ′. These space forming members 28 are separated from the groove bottom surface 141a of the stacking groove 141 by a support member 29 having the same configuration as the support member 29 of the transfer system 20 and a mounting frame 26 having the same cross-sectional shape as the mounting frame 26 of the transfer system 20. Supported by the state. As shown in FIG. 18, the mounting frames 26 are arranged above the accumulation groove 141 in the width direction of the settling tank 10 with a predetermined interval in a state of extending in the longitudinal direction of the settling tank 10. In this embodiment, three mounting frames 26 are arranged in each of the accumulation grooves 141. As shown in FIG. 18 and FIG. 20, among the three mounting frames 26, the mounting frame 26 arranged at the center in the width direction of the settling tank 10 has an upstream end portion fixed to the upstream wall 10h. The end portion on the downstream side is supported by the frame 261 and is supported by the receiving frame 261 fixed to the surface on the upstream side of the partition wall 10d. Further, as shown in FIGS. 18 and 19, of the three mounting frames 26, the two mounting frames 26 arranged on the outer side in the width direction of the sedimentation basin 10 have the upstream end portions of the sedimentation basin 10 respectively. Is supported by a receiving frame 261 fixed to the upstream wall 10h, and the end portion on the downstream side is supported on a mounting frame 26 arranged on the most upstream side in the transfer system 20. A support member 29 is suspended from each of the mounting frames 26.

  As shown in FIG. 20, in each of the space forming members 28 of the second transfer system 20 ′, a water supply pipe 271 has an outer end portion in the width direction of the sedimentation tank 10 and an intermediate portion in the width direction of the sedimentation tank 10. It is connected to the. Similar to the water supply pipe 271 shown in FIG. 14, these water supply pipes 271 penetrate the space forming member 28, enter the space forming member 28, and then bend to the width direction center side (sludge pit 14 side), and as shown in FIG. The same discharge port as the discharge port 27 shown is formed. As a result, in this embodiment, two discharge ports are provided in each space forming member 28 at intervals of about 5 m in the longitudinal direction. From these outlets, the water supplied from the water supply pipe 271 is discharged toward the sludge pit 14 side in the horizontal direction or the substantially horizontal direction. That is, in each of the pair of accumulation grooves 141, the outer side in the width direction of the sedimentation tank 10 is the upstream side in the discharge direction, and the inner side in the width direction of the sedimentation tank 10 (the sludge pit 14 side) is the downstream side in the discharge direction. Hereinafter, among the two discharge ports formed in each of the space forming members 28 of the second transfer system 20 ′, the discharge port on the upstream side in the discharge direction (outer side in the width direction of the settling tank 10) may be referred to as an outer discharge port. Therefore, the discharge port on the inner side in the width direction of the sedimentation tank 10 may be referred to as an inner discharge port. 18 and 19, in order to simplify the drawings, the water supply pipe 271 of the transfer system 20 'is omitted.

  Next, a second sludge removal method for removing sludge accumulated in the sedimentation tank 10 provided with the third embodiment of the transfer system from the sedimentation tank 10 will be described. This second sludge removal method corresponds to an example of a contaminant removal method.

  FIG. 21 is a flowchart showing the flow of the second sludge removal method.

  The sewage that has flowed into the settling basin 10 reaches the upstream end of the basin bottom 10a through the sludge pit 14 and the accumulation trench 141, and further flows along the extending direction of the basin bottom 10a. While the sewage flows, the sludge contained in the sewage settles in the sludge pit 14, the accumulation groove 141, and the pond bottom 10a. The sludge settled in the accumulation groove 141 flows down to the groove bottom surface 141a in the flow path F'through the flow path forming member 13 and the second flow path forming member 131 '. Further, it flows down to the groove bottom surface 141a in the flow path F'through the outer peripheral surface of the space forming member 28. In this way, sludge is deposited on the groove bottom surface 141a in the channel F '. Further, the sludge settled on the pond bottom portion 10a flows down through the flow channel forming member 13 and the second flow channel forming member 131 to the bottom surface 100a in the flow channel F. Further, the space forming member 28 is connected to the outer peripheral surface thereof and flows down to the bottom surface 100 a in the flow path F. In this way, sludge is deposited on the bottom surface 100a in the channel F.

  In the second sludge removing method according to the present embodiment, first, a sludge pump (not shown) provided outside the sludge pit 14 is driven to remove the sludge in the sludge pit 14 from the sludge pit 14 (step S1). . The sludge accumulated in the sludge pit 14 at this stage is mainly the sludge that has settled in the sludge pit 14 and accumulated in the sludge pit 14 among the sludge in the wastewater flowing into the sedimentation basin 10. The sludge pump continues to be driven until it is stopped in step S23 described later.

  Next, 500 liters of water per minute is discharged under water for 3 minutes from only the inner discharge port of the two discharge ports of each accumulation groove 141 (step S2). In step S2, water is discharged from the flow path F'to the space partitioned by the space forming member 28. Since water is discharged from the inner discharge port, a pressure difference is generated between the inside and the outside of the space forming member 28, and the sludge accumulated on the groove bottom surface 141a in the widthwise inner portion of the flow path F ′ is sucked in. It is sucked from the mouth into the space partitioned by the space forming member 28. Further, in the space partitioned by the space forming member 28, the sucked sludge moves downstream (to the sludge pit 14) in the discharge direction due to the flow of water discharged from the inner discharge port. The sludge that moves in the space partitioned by the space forming member 28 is less likely to go out of the space forming member 28 in the portion where the pressure difference is generated, and the sludge is prevented from rising. Thus, the sludge accumulated on the groove bottom surface 141a in the widthwise inner portion of the flow path F ′ moves in the space partitioned by the space forming member 28 and eventually reaches the sludge pit 14. The sludge that has reached the sludge pit 14 is transported to the outside of the settling tank 10 by the sludge pump, and the sludge is removed from the settling tank 10. The removal of sludge here corresponds to an example of a discharge process.

  Next, the discharge of water from the inner discharge port is stopped, and this time, 500 liters of water per minute is discharged from the outer discharge port under water for 3 minutes (step S3). In step S3 as well as in step S2, by discharging water into the space partitioned by the space forming member 28, a pressure difference is generated between the inside and the outside of the space forming member 28, and this time, the width of the flow path F ′ is increased. The sludge accumulated on the groove bottom surface 141a at the outer side in the direction is sucked into the space partitioned by the space forming member 28 from the suction port. Further, the sucked sludge moves in the space partitioned by the space forming member 28 toward the downstream side in the discharge direction (toward the inner discharge port) by the flow of the water discharged from the outer discharge port, and reaches the inner discharge port. To do. Since the momentum of water from the outer discharge port is reduced around the inner discharge port, the sludge that has reached the vicinity of the inner discharge port drops from the suction port of the space forming member 28 toward the groove bottom surface 141a. That is, sludge is accumulated on the groove bottom surface 141a around the inner discharge port in the flow path F '.

  Next, the discharge of water from the outer discharge port is stopped, and again, only from the inner discharge port, 500 liters of water per minute is discharged in water for 3 minutes, similarly to step S2 (step S4). By this step S4, the sludge accumulated on the groove bottom surface 141a around the inner discharge port in the flow path F ′ is sucked again into the space partitioned by the space forming member 28, and the sucked sludge is discharged on the downstream side in the discharge direction. It moves to the sludge pit 14 (toward the sludge pit 14) and finally reaches the sludge pit 14. Steps S2 to S4 correspond to an example of the moving process. The sludge that has reached the sludge pit 14 is removed from the settling tank 10 by a sludge pump. That is, also here, sludge removal by the sludge pump, which corresponds to an example of the discharging step, is also performed. The sludge discharged at this stage is, among the sludge in the wastewater that has flowed into the sedimentation basin 10, mainly the sludge that has settled in the accumulation groove 141 and accumulated on the groove bottom surface 141 a of the accumulation groove 141.

  Next, of the five discharge ports in each of the space forming members 28 provided in the pond bottom portion 10a, only the first discharge port on the most downstream side in the discharge direction (the most upstream side in the sedimentation tank 10) is 500 liters per minute. The water is discharged under water for 3 minutes (step S4). In step S4, water is discharged from the flow path F into the space partitioned by the space forming member 28. By discharging water from the first discharge port, a pressure difference is generated between the inside and the outside of the space forming member 28, and the sludge accumulated on the bottom surface 100a of the most upstream side portion of the flow path F is discharged from the suction port. It is sucked into the space partitioned by the space forming member 28. Further, in the space partitioned by the space forming member 28, the sucked sludge moves to the downstream side in the discharge direction (to the sludge pit 14 and the accumulation groove 141) by the flow of the water discharged from the first discharge port. Then, it eventually reaches the sludge pit 14 and the accumulation groove 141. The sludge that has reached the sludge pit 14 is transported to the outside of the settling tank 10 by the sludge pump, and the sludge is removed from the settling tank 10. Here again, sludge removal by a sludge pump, which corresponds to an example of the discharge step, is also performed.

  Then, the discharge of water from the first discharge port is stopped, and this time, 500 liters of water per minute is submerged in water for 3 minutes from only the second discharge port located upstream of the first discharge port in the discharge direction. Discharge (step S6). In step S6 as well, as in step S5, by discharging water into the space partitioned by the space forming member 28, a pressure difference occurs between the inside and outside of the space forming member 28, and this time, in the flow path F, the second The sludge accumulated on the groove bottom surface 141a around the discharge port is sucked into the space partitioned by the space forming member 28 from the suction port. Further, the sucked sludge moves in the space partitioned by the space forming member 28 to the downstream side in the discharge direction (toward the first discharge port) by the flow of the water discharged from the second discharge port, and Reach the exit. Since the momentum of water from the second discharge port is reduced around the first discharge port, the sludge that has reached the vicinity of the first discharge port drops from the suction port of the space forming member 28 toward the bottom surface 100a. That is, the sludge is deposited on the bottom surface 100a of the flow path F around the first discharge port.

  Next, the discharge of water from the second discharge port is stopped, and again, only from the first discharge port, 500 liters of water per minute is discharged for 3 minutes under water, similarly to step S5 (step S7). By this step S7, the sludge accumulated on the bottom surface 100a around the first discharge port in the flow path F is sucked into the space partitioned by the space forming member 28, and the sucked sludge is discharged to the downstream side in the discharge direction ( It moves in the space partitioned by the space forming member 28 (toward the sludge pit 14 or the accumulating groove 141) and eventually reaches the sludge pit 14 or the accumulating groove 141. The sludge that has reached the sludge pit 14 is removed from the settling tank 10 by a sludge pump. That is, also here, sludge removal by the sludge pump, which corresponds to an example of the discharging step, is also performed.

  Next, after stopping the discharge of water from the first discharge port, the discharge from the third discharge port (step S8) and the discharge from the second discharge port (step S9) are performed by the same process as steps S6 and S7. , And the discharge from the first discharge port (step S10). By performing steps S8 to S10, the sludge accumulated on the bottom surface 100a around the third discharge port reaches the sludge pit 14 and the accumulation groove 141, and the sludge reaching the sludge pit 14 is processed by the sludge pump. Removed from settling basin 10. That is, also here, sludge removal by the sludge pump, which corresponds to an example of the discharging step, is also performed.

  Next, after stopping the discharge of water from the first discharge port, the discharge from the fourth discharge port (step S11) and the discharge from the third discharge port (step S12) are performed by the same process as steps S8 to S10. ), Discharge from the second discharge port (step S13), and discharge from the first discharge port (step S14). By performing steps S11 to S14, the sludge accumulated on the bottom surface 100a around the fourth discharge port reaches the sludge pit 14 and the accumulation groove 141, and the sludge reaching the sludge pit 14 is settled by the sludge pump. Removed from pond 10. That is, also here, sludge removal by the sludge pump, which corresponds to an example of the discharging step, is also performed.

  Next, after stopping the discharge of water from the first discharge port, the discharge from the fifth discharge port (step S15) and the discharge from the fourth discharge port (step S16) are performed by the same process as steps S11 to S14. The steps of discharging from the third discharge port (step S17), discharging from the second discharge port (step S18), and discharging from the first discharge port (step S19) are performed. By carrying out Steps S15 to S19, the sludge accumulated on the bottom surface 100a around the fifth discharge port reaches the sludge pit 14 and the accumulation groove 141, and the sludge reaching the sludge pit 14 is precipitated by the sludge pump. Removed from pond 10. That is, also here, sludge removal by the sludge pump, which corresponds to an example of the discharging step, is also performed.

  By performing steps S5 to S19, the sludge settled on the bottom 10a of the pond is moved to the sludge pit 14 and the accumulation groove 141, and the sludge reaching the sludge pit 14 is removed from the sedimentation pond 10 by the sludge pump. It These steps S5 to S19 correspond to an example of the moving process.

  Next, after stopping the discharge of water from the first discharge port, similarly to steps S2 to S4, the discharge from the inner discharge port (step S20), the discharge from the outer discharge port (step S21), and the inner side. The ejection from the ejection port (step S22) is performed. By performing steps S20 to S22, the sludge settled on the pond bottom 10a and moved to the accumulation groove 141 by steps S5 to S19 reaches the sludge pit 14. The movement of the sludge here also corresponds to an example of the movement process. The sludge that has reached the sludge pit 14 is removed from the settling tank 10 by a sludge pump. That is, also here, the removal of sand by the sludge pump, which corresponds to an example of the discharging step, is also performed.

  Then, when the discharge of water from the inner discharge port is finished and a predetermined time has elapsed thereafter, the sludge pump started to be driven in step S1 is stopped (step S23). Further, when a predetermined time further elapses, or when sludge has settled to some extent in the sludge pit 14 due to the sludge that has settled, step S1 is performed again. In this way, steps S1 to S23 are repeatedly performed after the acceptance of waste water is started.

  According to the second sludge removal method, the sludge can be sufficiently moved in the sedimentation tank 10 while suppressing the sludge from rising, and the sludge can be removed from the sedimentation tank.

  Next, a modified example of the transfer system described above will be described.

  FIG. 22 is a diagram showing a modified example of how to support the space forming member. In FIG. 22, as in FIG. 14, the left-right direction of the drawing is the width direction.

  The space forming member 28 shown in FIG. 14 was supported by attaching the supporting member 29 to the cylindrical portion 283 of the upper end portion 282, but the space forming member 28 shown in FIG. 22 is on both sides of the suction port 281. The lower end 284 and the upper end portion 282 are supported by the support 39. The support 39 is formed by bending a plate material such as stainless steel, has a length of about several tens of mm in the longitudinal direction, and has a predetermined interval along the extending direction of the space forming member 28. There are multiple open spaces. Further, the support body 39 includes a U-shaped frame portion 391, a pair of lower end support portions 392 extending in the vertical direction, and a frame portion 391 and a lower end support portion 392 extending parallel to the bottom surface 100a. It has a pair of connecting parts 393 connected. The frame portion 391 contacts the upper end portion 282 of the space forming member 28 and supports the upper end portion 282 with the open portion facing downward. The lower end support portion 392 supports each lower end 284 of the space forming member 28. The pair of connecting portions 393 are fixed on the base member 40 arranged on the bottom surface 100a. The space forming member 28 is supported by the support 39 with the suction port 281 separated from the bottom surface 100a.

  FIG. 23 is a diagram showing a modification in which the space forming member 28 shown in FIG. 13 is installed movably in the width direction. In FIG. 23, as in FIG. 13, the left-right direction of the drawing is the width direction.

  The space forming member shown in FIG. 13 was supported in a state where the position in the width direction was fixed by attaching the upper screw member 293 of the support member 29 to the attachment frame 26, but in the present modification, the attachment is performed. A rail member 37 extending in the width direction is provided instead of the frame 26, and a roller member 294 that engages with the rail member 37 movably in the width direction is provided in place of the upper screw member 293 of the support member 29. There is. Further, in this modification, the flow path forming member 13 is omitted and the flow path F is not formed, and the pond bottom portion 10a is a flat surface including the bottom surface 100a. The roller member 294 can be moved in the width direction along the rail member 37 by a driving means (not shown), whereby the space formation supported by the support member 29 is formed as shown by the arrow in the width direction of the drawing. The member 28 can be moved in the width direction. By doing so, every time the space forming member 28 is slid in the width direction, water is discharged from the discharge port 27 and the sludge can be transferred to the sludge pit 14 side (see FIG. 11) over a wide width direction region. become able to.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims. For example, although the transfer system 20 is provided in the settling basin 10 in the above-described embodiment, the transfer system 20 is provided in a reservoir such as a dam lake and the sediment settling at the bottom of the dam lake is moved in one direction to a predetermined position. May be collected at the place. The earth and sand collected in a predetermined place may be removed from the dam lake or the like by suctioning with a known sand discharge pipe. Further, when the transfer system 20 is provided in a reservoir such as a dam lake, it is preferable that the space forming member is moved as in the modification shown in FIG. Further, the transfer system 20 may be provided in a factory or the like, and the metal powder or the like generated in the factory or the like may be moved in one direction and collected in a predetermined place.

  In addition, even if the constituent requirements are included only in the description of each of the embodiment and the modification described above, the constituent requirement may be applied to another embodiment and the modification.

1 Settling basin 1a Pond bottom 3 Trough 3a Opening 4 Sand collecting pit 6 Sloping surface 7 Discharge port 8 Space forming member 81 Suction port 82 Upper end part S1, S2 space 10 Settling basin 10a Pond bottom 14 Sludge pit 141 Accumulation ditch 20 Transfer system 28 Space forming member 27 Discharge port 29 Support member 33 Trough F Flow path S3, S4 Space

Claims (2)

A transfer system in which contaminants contained in the received liquid settle to the bottom,
A space forming member that extends along the bottom portion, forms a space with an upper end portion closed, and has an opening provided below the upper end portion and separated from the bottom portion,
A discharge port for discharging a fluid into the space,
The transfer system has a flat shape, is positioned above the opening, and discharges fluid toward a downstream side in the transfer direction of the contaminant.   The transfer system according to claim 1, wherein the discharge port discharges the fluid at a discharge pressure of 0.05 MPa or more and 0.3 MPa or less.