JP2019188396A - Solid-liquid separation facility - Google Patents

Abstract

To provide a solid-liquid separation facility that can efficiently separate solid included in received liquid.SOLUTION: A solid-liquid separation facility 10 is provided with: a plurality of upstream-side nozzles 71a and 71b which discharge water for moving solid sedimented in a plurality of upstream-side groove parts 31a and 31b respectively to an aggregation part 4; a plurality of downstream-side nozzles 71c and 71d which discharge water for moving solid sedimented in a plurality of downstream-side groove parts 31c and 31d respectively to the aggregation part 4; and an aggregation part nozzle 72 that discharges water for moving solid moved to the aggregation part 4 toward exhausting means P1 in the aggregation part 4. All of the upstream-side nozzles 71a and 71b, the downstream-side nozzles 71c and 71d and the aggregation part nozzle 72 discharge water by opening opening/closing valves provided in the nozzles respectively, where one opening/closing valve of the opening/closing valves provided in the nozzles respectively is started to be closed and at the same time the other opening/closing valve is started to be opened.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a solid-liquid separation facility that separates a solid contained in the liquid by flowing the received liquid in a flow-down direction perpendicular to the pond width direction of a settling basin.

  As facilities for sewage treatment, solid-liquid separation facilities equipped with a sedimentation basin and solid-liquid separation facilities equipped with a sedimentation basin are used. The sedimentation basin is a sedimentation basin that accepts sewage such as sewage or rainwater, and sinks the sand contained in the sewage, moves the sedimented sand to the sand collection pit, and lifts the sand collected in the sand collection pit. It is removed by a sand pump. The sewage that has passed through the settling basin flows into the pump well and is discharged by a pumping pump installed in the pump well. The sedimentation basin is a sedimentation basin that accepts the sewage from which the sand has been removed in the sedimentation basin and settles the sludge contained in the received sewage, and moves the settled sludge to the sludge pit and collects it in the sludge pit. Sludge is removed by a sludge pump.

  In a sand basin, which is one of the sedimentation ponds, a plurality of upstream grooves aligned in the pond width direction upstream of the sand pit provided with the sand pump, and in the pond width direction downstream of the sand pit There is known a sand basin provided with a plurality of downstream grooves and provided with a nozzle in each of the upstream grooves and the downstream grooves (for example, Patent Document 1). Hereinafter, the upstream groove portion and the downstream groove portion may be simply referred to as a groove portion. In the sand basin described in Patent Document 1, a plurality of groove portions extend toward the sand pit, and each of the plurality of groove portions is provided with three nozzles at predetermined intervals in the groove extending direction. ing.

  In the solid-liquid separation technique implemented in the sand basin described in Patent Document 1, the sand contained in the received sewage is settled in a plurality of grooves, and then water is discharged from the nozzles and deposited in the grooves. Move the sand. That is, in the upstream groove portion, water is discharged from the most upstream nozzle, water is discharged from the intermediate nozzle, and finally water is discharged from the most downstream nozzle. Thereby, the sand can be gradually moved from the upstream side toward the downstream side toward the sand settling pit. Also in the downstream groove portion, after water is discharged from the most downstream nozzle, water is discharged from the intermediate nozzle, and finally water is discharged from the most upstream nozzle. Thereby, the sand can be gradually moved from the downstream side toward the upstream side toward the sand settling pit. As described above, instead of discharging water from a plurality of nozzles at once, it is possible to reduce the discharge amount of the sand collecting pump that supplies water to the nozzles by discharging water sequentially toward the sand settling pit. it can.

JP 2002-282609 A

  However, the solid-liquid separation technique described in Patent Document 1 does not consider the essential function in the solid-liquid separation facility, that is, the function of separating the solid contained in the received liquid from the liquid.

  An object of this invention is to provide the solid-liquid separation facility which can isolate | separate the solid contained in the received liquid efficiently in view of the said situation.

The solid-liquid separation facility of the present invention that solves the above-described object is a solid-liquid separation facility that separates a solid contained in the liquid from the liquid by allowing the received liquid to flow down in a flow direction perpendicular to the pond width direction of the sedimentation basin. In
A discharge means for discharging the solid provided in the stacking unit;
A plurality of upstream groove portions extending from the upstream side in the flow-down direction to the accumulation portion with respect to the accumulation portion and arranged in the pond width direction;
A plurality of downstream grooves extending from the downstream side of the flow-down direction to the stacking portion than the stacking portion and arranged in the pond width direction;
A plurality of upstream nozzles for discharging water for moving solids settled in each of the plurality of upstream grooves to the accumulation unit;
A plurality of downstream nozzles for discharging water for moving solids settled in each of the plurality of downstream grooves to the accumulation unit;
A stacking unit nozzle that discharges water for moving the solid moved to the stacking unit toward the discharging means in the stacking unit;
The upstream nozzle, the downstream nozzle, and the accumulation part nozzle all discharge water by opening an on-off valve provided in each,
Of the on-off valves provided in each of the upstream nozzle, the downstream nozzle, and the accumulation section nozzle, opening of the other on-off valve is started simultaneously with the start of closing of the on-off valve. And

In the solid-liquid separation facility of the present invention,
The on-off valve has substantially the same length of the opening / closing time until the valve is fully opened from the fully closed state to the fully closed state.
The on-off valves provided in the upstream nozzle, the downstream nozzle, and the accumulation section nozzle, respectively, have a uniform length of the opening / closing time and a uniform length of the opening / closing time. It may be a feature.

Furthermore, in the solid-liquid separation facility of the present invention,
The upstream nozzle, the downstream nozzle, and the accumulation unit nozzle may discharge water supplied from a common pump.

  According to the solid-liquid separation facility of the present invention, it is possible to provide a solid-liquid separation facility that can efficiently separate the solid contained in the received liquid.

It is the top view which looked at the solid-liquid separation facility from the upper part. It is AA sectional drawing of the solid-liquid separation facility shown in FIG. It is BB sectional drawing of the solid-liquid separation facility shown in FIG. It is a figure which expands and shows the C section enclosed in the circle in FIG. It is a timing chart which shows the drive timing and stop timing of the pump and nozzle which were installed in the solid-liquid separation facility shown in FIG. 1 and FIG.

  Embodiments of the present invention will be described below with reference to the drawings. The solid-liquid separation facility is used, for example, in a facility that performs sewage treatment including a sedimentation basin such as a sand basin or a sedimentation basin. Moreover, the solid-liquid separation method is implemented in the solid-liquid separation facility provided with sedimentation pond parts, such as a sedimentation basin and a sedimentation basin, for example. In the present embodiment, a solid-liquid separation facility having a sedimentation basin as a sedimentation basin and a solid-liquid separation method implemented in the solid-liquid separation facility having this sedimentation basin will be described as examples. The sand basin is disposed upstream of the sewage treatment facility and removes sand contained in sewage such as sewage or rainwater from the sewage.

  FIG. 1 is a plan view of the solid-liquid separation facility 10 as viewed from above, and FIG. 2 is a cross-sectional view taken along line AA of the solid-liquid separation facility 10 shown in FIG. In addition, in FIG. 2, the sand pump P1, the sand collection water pump P2, and the water pump P3 which are not originally shown in AA sectional drawing are shown for convenience of explanation.

  As shown in FIG. 1, the solid-liquid separation facility 10 is a rectangular pond that is provided with a sand basin 11, a pump well 12, and a connecting portion 13 that connects the sand basin 11 and the pump well 12. is there. Hereinafter, the long side direction of the solid-liquid separation facility 10 may be referred to as a longitudinal direction, and the short side direction may be referred to as a pond width direction. That is, in this embodiment, the direction orthogonal to the pond width direction corresponds to the longitudinal direction. The solid-liquid separation facility 10 shown in FIGS. 1 and 2 receives sewage from the left side of the figure, and the received sewage slowly flows to the pump well 12 toward the right side of the figure (shown in FIGS. 1 and 2). See thick arrow). 1 and 2, the left side of the figure is the upstream side, the right side is the downstream side, and the right direction of the figure is the downflow direction. That is, the received sewage flows down in the longitudinal direction.

  WL shown in FIG. 2 represents the surface of sewage, and the position of the water surface WL is maintained at a set water level. The sand contained in the sewage settles in the sand basin 11 while the sewage slowly flows toward the pump well 12. The sedimentation basin 11 is a pond that sinks sand contained in the sewage received by the solid-liquid separation facility 10, and corresponds to an example of a sedimentation basin section. The sewage that has passed through the sand basin 11 flows into the pump well 12 through the connecting portion 13, and is discharged by the pumping pump P 3 installed in the pump well 12. In the sand basin 11, the area below the connecting portion 13 forms a sand reservoir R1 that accumulates sand, and sewage flows to an area above the sand reservoir R1. That is, the region from the connecting portion 13 to the water surface WL forms a flow-down region R2 through which dirty water flows. The area of the surface obtained by cutting the flowing region R2 in the width direction corresponds to the flowing cross-sectional area.

  A dust remover 2 is provided on the upstream side of the sand basin 11. This dust remover 2 is for removing stone blocks, residue, etc. of a predetermined size or more from the solid contained in the sewage that is about to flow into the sand basin 11. The dust remover 2 includes an endless chain 21, a plurality of rakes 22 attached to the endless chain 21 at intervals, and a filtration screen 23 that is submerged in water. The endless chain 21 is provided so as to stand obliquely on both sides of the solid-liquid separation facility 10 in the width direction, and is wound around the ground side sprocket 211 and the pond bottom side sprocket 212 as shown in FIG. It has been. When the endless chain 21 is driven, the rake 22 enters and exits the water. The filtration screen 23 is disposed on the downstream side of the endless chain 21. In the filter screen 23, bars extending in the vertical direction are arranged at a predetermined interval (for example, 25 mm to 75 mm) to block the passage of a solid having a size greater than the predetermined interval. In the present embodiment, bars extending in the vertical direction are arranged at intervals of 75 mm. The solid obstructed by the filter screen 23 is lifted up by the rake 22, and the picked up solid is placed on a transport means such as a belt conveyor (not shown) on the ground side.

  As shown in FIGS. 1 and 2, the sand settling basin 11 provided on the downstream side of the dust remover 2 is provided in the order of description from the upstream side to the downstream side, the upstream pond bottom 110 a, the sand collecting pit 4, and the downstream side. A pond bottom 110b is provided. Hereinafter, when it is not necessary to distinguish the upstream pond bottom 110a and the downstream pond bottom 110b, they may be collectively referred to as the pond bottom 110. The sand settled on the pond bottom 110 moves to the sand collecting pit 4 by water discharged from the sand collecting nozzle 71 described later. As a result, the sand in the sewage flowing into the sand basin 11 is collected in the sand collecting pit 4. That is, the sand collecting pit 4 corresponds to an example of a collecting portion, and the sand in the sewage flowing into the sand settling basin 11 corresponds to an example of solid contained in the received liquid. Specifically, in the upstream pond bottom 110a, the direction from the upstream toward the sand collecting pit 4 (see the thin arrow in the right direction shown in FIGS. 1 and 2) is the sand movement direction, and the downstream pond bottom 110b. Then, the direction from the downstream side toward the sand collecting pit 4 (see the thin arrow in the left direction shown in FIGS. 1 and 2) is the sand moving direction. For this reason, in the upstream pond bottom 110a, the flow direction (thick arrow in the figure) and the movement direction (thin arrow in the figure) coincide, but in the downstream pond bottom part 110b, the flow direction (thick arrow in the figure) and movement direction. (Thin arrow in the figure) is in the opposite direction.

  As shown in FIG. 1, the upstream pond bottom 110a is provided with two troughs 31, 31 extending in the longitudinal direction and arranged in the pond width direction. Of the two troughs 31, 31 provided on the upstream pond bottom 110a, in the following description, the trough 31 positioned on the upper side in FIG. 1 is referred to as the upstream first trough 31a and is positioned on the lower side in FIG. The trough 31 is sometimes referred to as the upstream second trough 31b. Moreover, the two troughs 31 and 31 extended in the longitudinal direction and arranged in the pond width direction are provided also in the downstream pond bottom part 110b. Of the two troughs 31, 31 provided on the downstream pond bottom 110b, in the following description, the trough 31 located on the upper side in FIG. 1 is referred to as a downstream first trough 31c, and is located on the lower side in FIG. The trough 31 is sometimes referred to as a downstream second trough 31d. These troughs 31 correspond to a plurality of grooves extending in a direction orthogonal to the pond width direction and arranged in the pond width direction. The upstream first trough 31a and the upstream second trough 31b correspond to a plurality of upstream grooves, and the downstream first trough 31c and the downstream second trough 31b correspond to a plurality of downstream grooves. In the present embodiment, each trough 31 is set to have a total length of about 10 m.

  Each of these troughs 31 is provided with a pair of inclined surfaces 32 and 32 that are inclined downward from both sides in the pond width direction toward the trough 31. The pair of inclined surfaces 32, 32 are surfaces that are separated from each other as they go upward. In the present embodiment, the inclined surface 32 is formed by placing concrete. Moreover, the connection part 33 of the inclined surface 32 and the inclined surface 32 is formed in the state extended in the longitudinal direction in the approximate center of the pond width direction of each of the upstream pond bottom part 110a and the downstream pond bottom part 110b.

  As shown in FIG. 1, each of the plurality of troughs 31 is provided with a sand collecting nozzle 71. Specifically, an upstream first sand collecting nozzle 71a is provided upstream of the upstream first trough 31a, and an upstream second sand collecting nozzle 71b is provided upstream of the upstream second trough 31b. ing. A downstream first sand collecting nozzle 71c is provided downstream of the downstream first trough 31c, and a downstream second sand collecting nozzle 71d is provided downstream of the downstream second trough 31d. FIG. 2 shows an upstream first sand collecting nozzle 71a disposed on the upstream side of the upstream first trough 31a and a downstream first sand collecting nozzle 71c disposed on the downstream side of the downstream first trough 31c. ing.

  As shown in FIG. 1, the downstream side of each of the upstream first trough 31a and the upstream second trough 31b is connected to the sand collecting pit 4 and upstream of each of the downstream first trough 31c and the downstream second trough 31d. The side is also connected to the sand collection pit 4. A space forming member 8 is provided in the trough 31. The space forming member 8 extends along the trough 31. Detailed description of the trough 31 and the space forming member 8 will be described later.

  As shown in FIG. 1, the sand collecting pit 4 has a flat surface portion 41 provided at a central portion in the pond width direction and a pair of inclined surface portions 42, 42 provided on both sides of the flat surface portion 41 in the pond width direction. is doing. The flat surface portion 41 is configured by a flat surface having a rectangular shape in plan view, and the sand pump P <b> 1 is disposed at the central portion of the flat surface portion 41. As shown in FIG. 2, the sand pump P <b> 1 includes a suction port PO located at a predetermined height from the flat surface portion 41. This sand raising pump P1 sucks the sand collected in the sand collecting pit 4 from the suction port PO and conveys it to a sand settling machine or the like through a sand raising pipe (not shown).

  The inclined surface portion 42 is configured by an inclined surface inclined downward toward the flat surface portion 41, whereby the sand settled on the inclined surface portion 42 is inclined toward the sand pump P <b> 1 disposed on the flat surface portion 41. Will continue. The area of the inclined surface portion 42 and the inclination angle are set according to the length of the sand collecting pit 4 in the pond width direction. For example, when the length of the sand collecting pit 4 in the pond width direction is long, the area of the inclined surface portion 42 is set to be relatively large, and the inclination angle is set to be relatively large. On the other hand, when the length of the sand collecting pit 4 in the pond width direction is short and the sedimented sand can be sufficiently moved around the sand pump P1 by water discharged from the pit sand collecting nozzle 72 described later. May omit the inclined surface portion 42. In the present embodiment, the inclination angle of the inclined surface portion 42 is set to be larger than the inclination angle of the inclined surface 32 connected to the trough 31.

  As shown in FIG. 1, a pair of pit sand collecting nozzles 72, 72 disposed along the pair of inclined surface portions 42, 42 are provided inside the sand collecting pit 4. Each of the pit sand collecting nozzles 72 has two discharge ports 721 that are divided into two forks and arranged at intervals in the longitudinal direction. These discharge ports 721 discharge water along the inclined surface portion 42 toward the sand pump P1 disposed in the center of the sand collecting pit 4 in the width direction. Thereby, the sand collected in the sand collection pit 4 is collected around the sand pump P1.

  As shown in FIG. 1, a pair of stirring nozzles 73 and 73 are further provided inside the sand collecting pit 4. In FIG. 1, only the stirring nozzle 73 is shown to simplify the drawing, and the water supply branch pipe connected to the stirring nozzle 73 is omitted. In FIG. 2, the stirring nozzle 73 itself is also omitted. The pair of agitation nozzles 73, 73 are arranged around the sand pump P1, discharge water toward the periphery of the suction port PO (see FIG. 2) of the sand pump P1, and around the suction port PO. It is what disturbs the accumulated sand. This prevents the suction port PO (see FIG. 2) of the sand pump P1 from being blocked and prevents the pump from being locked due to so-called sand biting. When the length of the sand collecting pit 4 in the pond width direction is short, either the pit sand collecting nozzle 72 or the stirring nozzle 73 is omitted, and the pit sand collecting nozzle 72 and the stirring nozzle 73 are used by the other. A configuration that provides both functions can also be employed.

  As shown in FIGS. 1 and 2, the downstream pond bottom part 110b and the pump well part 12 are connected by the connecting part 13, and as described above, the height position of the connecting part 13 is the sand pool R1. It becomes a boundary with the flow-down region R2 (see FIG. 2). The pump well 12 stores sewage from which sand has been removed. Inside the pump well 12, a sand collecting water pump P2 and a pumping pump P3 are provided. As shown in FIG. 2, the sand collecting water pump P <b> 2 is connected to each nozzle by a water supply main pipe 741 and a plurality of water supply branch pipes 742. FIG. 2 shows a state where the sand collecting water pump P2 is connected to the upstream first sand collecting nozzle 71a, the downstream first sand collecting nozzle 71c, and the pit sand collecting nozzle 72 on one side. Although not shown, the sand collecting water pump P2 is also connected to the upstream second sand collecting nozzle 71b, the downstream second sand collecting nozzle 71d, and the pit sand collecting nozzle 72 on the other side. , And a pair of stirring nozzles 73, 73 (see FIG. 1).

  One end of the water supply main pipe 741 is connected to the sand collecting water pump P2, and a plurality of water supply branch pipes 742 are branched from the other end. Each of the plurality of water supply branch pipes 742 is provided with a sand collection adjusting valve V1 and a sand collection valve V2. The sand collection adjusting valve V1 adjusts the flow rate of water supplied to each nozzle, and is configured by a manual ball valve, for example. The sand collecting valve V2 supplies water to each nozzle by opening and stops supplying water to each nozzle by closing, and is constituted by an electric ball valve, for example. In this embodiment, the opening / closing time of the sand collecting valve V2 is set to 30 seconds. For this reason, when opening of the sand collecting valve V2 is started from the fully closed state, the flow rate of water discharged from the nozzle connected to the sand collecting valve V2 gradually increases, and the fully opened state is reached in about 30 seconds. . When the sand collecting valve V2 is fully opened, water having a flow rate adjusted by the sand collecting adjusting valve V1 is discharged from the nozzle. Further, when the sand collecting valve V2 is closed from the fully open state, the flow rate of water discharged from the nozzle gradually decreases, and the fully closed state is reached in about 30 seconds. When the sand collecting valve V2 is fully opened, the discharge of water from the nozzle is completely stopped. The opening / closing time of the sand collecting valve V2 can be set as appropriate, and the opening / closing time may be different for each of the sand collecting nozzle 71, the pit sand collecting nozzle 72, and the stirring nozzle 73. In addition, in this embodiment, the structure which provides one sand collection adjusting valve V1 and one sand collection valve V2 with respect to a pair of pit sand collection nozzles 72 and 72 is employ | adopted. Thereby, water is discharged from each of the pair of pit sand collecting nozzles 72 and 72 at the same timing, and the flow rate of the discharged water is also the same. Moreover, although illustration is abbreviate | omitted, the structure which provides one sand collection adjustment valve V1 and one sand collection valve V2 also with respect to a pair of stirring nozzles 73 and 73 is employ | adopted. Of course, each of the pair of pit sand collecting nozzles 72, 72 may be provided with a sand collecting adjusting valve V1 and a sand collecting valve V2, and each of the pair of stirring nozzles 73, 73 has a sand collecting adjusting valve V1 and a sand collecting valve. V2 may be provided.

  Next, the structure of the trough 31 and the inclined surface 32 is demonstrated in detail using FIG. FIG. 3 is a BB cross-sectional view of the solid-liquid separation facility 10 shown in FIG. The upstream pond bottom 110a and the downstream pond bottom 110b are configured symmetrically with the sand collecting pit 4 interposed therebetween. For this reason, here, the configuration provided in the downstream pond bottom 110b will be described as an example.

  As shown in FIG. 3, each of the downstream first trough 31c and the downstream second trough 31d has a pair of upper edges 311 and 311 that define an opening, and obliquely upward from each of the pair of upper edges 311 and 311. An inclined surface 32 extending in the direction is provided. In FIG. 3, the inclined surface 32 extending from the left upper edge 311 of the downstream first trough 31c is connected to the side wall 34 of the sand basin 11, and the inclined surface 32 extending from the right upper edge 311 of the downstream second trough 31d. Is also connected to the side wall 34 of the sand basin 11. Further, the inclined surface 32 extending from the upper edge 311 on the right side of the downstream first trough 31c and the inclined surface 32 extending from the upper edge 311 on the left side of the downstream second trough 31d are connected at the center of the pond width direction, and are connected. 33 is formed. In this embodiment, although the connection part 33 is comprised in the pointed part where the inclined surface 32 and the inclined surface 32 contact | abutted, as shown with the dashed-dotted line of FIG. The connecting portion 33 may be formed of a flat portion, or may be the connecting portion 33 in which the inclined surface 32 and the inclined surface 32 are connected in an arc shape. The sand that has settled on the downstream pond bottom 110 b flows down along the inclined surface 32 and enters the trough 31 from the opening defined by the pair of upper edges 311, 311.

  By providing the plurality of troughs 31 and the inclined surfaces 32 extending from the pair of upper edges 311, 311 of the troughs 31, the sedimented sand is deposited on the inclined surfaces 32 even when the basin width of the sand basin 11 is wide. It becomes possible to collect in the trough 31 without letting it go. Here, when the pond width of the solid-liquid separation facility 10 becomes wider, an aspect in which three or more troughs 31 are arranged side by side in the pond width direction is necessary in order to prevent sand from accumulating on the inclined surface 32. In some cases. Even in this case, since the inclined surface 32 is provided, the number of troughs 31 can be reduced by the amount of the inclined surface 32. Thereby, the number of sand collecting nozzles 71 as a moving mechanism can be suppressed, and an increase in construction cost can also be suppressed.

  Furthermore, since the height of the connecting portion 33 is equal to or less than the height of the connecting portion 13, the inclined surface 32 does not block the flow-down region R <b> 2 above the connecting portion 13. As a result, it is possible to prevent the flow cross-sectional area from decreasing and the sand collection efficiency from decreasing. That is, the flow rate of sewage flowing through the sand settling basin 11 is increased by reducing the flow cross-sectional area, and the problem that the sand does not easily settle to the pond bottom 110 does not occur. In addition, by suppressing the height of the connecting portion 33 to be equal to or less than the height of the connecting portion 13, for example, when the inclined surface 32 is formed of concrete, an increase in the amount of placement can be suppressed.

  In the present embodiment, the inclination angle (angle (elevation angle)) α of the inclined surface 32 is set to about 25 degrees. The inclination angle α is preferably set in the range of 15 degrees to 45 degrees, and particularly preferably set in the range of 15 degrees to 40 degrees. If the inclination angle α is less than 15 degrees, the sand that has settled on the inclined surface 32 does not flow down to the trough 31 along the inclined surface 32 and may accumulate on the inclined surface 32. On the other hand, in order to move the sand that has settled on the inclined surface 32 to the trough 31, it is sufficient to set the inclination angle α to 45 degrees. When the inclination angle α exceeds 45 degrees, the concrete that forms the inclined surface 32 is formed. This is not preferable because the amount of casting increases significantly. In addition, in order to sufficiently suppress the amount of the concrete that forms the inclined surface 32, the inclination angle α is preferably 40 degrees or less. In the present embodiment, the inclination angles α of the plurality of inclined surfaces 32 are set to be approximately the same. For example, the inclination angle α of the inclined surface 32 connected to the side wall 34 is connected to another inclined surface 32. Thus, the inclination angle α may be made different for each inclined surface 32, for example, by making it larger than the inclination angle α of the inclined surface 32 forming the connecting portion 33.

  Next, the structure of the trough 31, the sand collecting nozzle 71, and the space formation member 8 is demonstrated in detail using FIG. FIG. 4 is an enlarged view of a portion C surrounded by a circle in FIG. Here, the downstream first trough 31c and the downstream first sand collecting nozzle 71c will be described as examples. In FIG. 4, the direction from the back to the front of the paper is the sand moving direction.

  The trough 31 of the present embodiment has a shape in which approximately 1/3 above a stainless cylindrical body having a total length of 10 m, a diameter of 300 mm, and a plate thickness of about 3 mm is cut out, and opens upward. Moreover, the trough 31 has the internal peripheral surface 312 and the space S1 demarcated by this internal peripheral surface is formed. The cross-sectional shape of the trough 31 in the pond width direction is not limited to an arc shape, and may be a U shape, a V shape, or the like.

  The space forming member 8 partitions the space S1 in the trough 31, and forms a space S2 in which a portion above the lower end is closed. Further, the space forming member 8 of the present embodiment has a shape in which approximately 1/6 of a stainless steel cylinder having a diameter of about 150 mm and a plate thickness of about 3 mm is cut out, and opens downward. . Hereinafter, this opened portion is referred to as a suction port 81. The space forming member 8 is supported on the trough 31 by a support member (not shown) at an end on the upstream side in the moving direction and an end on the downstream side in the moving direction.

  The sand collecting nozzle 71 has a water supply branch pipe 742 connected to the rear end portion thereof and a discharge port 711 at the tip end portion thereof. The sand collecting nozzle 71 of this embodiment is formed by crushing a round pipe into a flat shape. When the water stored in the pump well 12 shown in FIG. 2 is supplied to the sand collecting nozzle 71 by the sand collecting water pump P2 through the water supply main pipe 741 and the water supply branch pipe 742, the water supplied to the sand collecting nozzle 71 is supplied. Is discharged from the discharge port 711. In the present embodiment, the discharge flow rate of water discharged from the discharge port 711 is set to 8 m / sec or more, and the discharge pressure is set to 0.05 MPa or more and 0.3 MPa or less. In the present embodiment in which the total length of the trough 31 is set to about 10 m, the flow rate of water discharged from the discharge port 711 is adjusted to about 2000 liters per minute. In addition, when setting the full length of the trough 31 to about 5 m, the flow volume of the water discharged from the discharge outlet 711 is adjusted to about 1500 liters per minute. Thus, the flow rate of the water discharged from the discharge port 711 is appropriately adjusted according to the total length of the trough 31 and the like. In the present embodiment, the water discharged from the discharge port 711 uses sewage stored in the pump well 12, but other sewage received in the sewage treatment plant may be used, such as water Other water may be used.

  When water is discharged into the space S2 of the space forming member 8 from the discharge port 711 of the sand collecting nozzle 71, a pressure difference is generated between the inside (space S2) and the outside of the space forming member 8, and the inside of the trough 31 (space S1). The sand accumulated in () is sucked into the space S2 from the suction port 81 as indicated by the curved arrow shown in FIG. Furthermore, in the space S <b> 2 of the space forming member 8, the sucked sand moves toward the sand collecting pit 4 (see FIGS. 1 and 2) by the flow of water discharged from the discharge port 711. The sand moving in the space S2 is unlikely to go out of the space forming member 8 at the portion where the pressure difference is generated, and the sand is prevented from rolling up. Therefore, it is possible to suppress the sand from rolling up while sufficiently moving the sand. That is, the sand collecting nozzle 71 and the space forming member 8 correspond to an example of a moving mechanism.

  Then, the solid-liquid separation method implemented in the solid-liquid separation facility 10 demonstrated so far is demonstrated. First, the process up to the sedimentation step will be described. In the solid-liquid separation facility 10, the process up to the sedimentation step is continued while the sewage is received.

  When the sewage flowing into the solid-liquid separation facility 10 passes through the dust remover 2 shown in FIG. 1 and FIG. 2, the residue and the like mixed in the sewage are removed. The sewage that has passed through the dust remover 2 reaches the upstream end of the upstream pond bottom 110a, and further flows toward the pump well 12 in the downstream region R2 shown in FIG. While the sewage flows to the pump well 12, most of the sand contained in the sewage settles in the sand pool R1. Some sand settles in the sand collecting pit 4 and some sand settles in the upstream pond bottom 110a and the downstream pond bottom 110b. The sand settled in the upstream pond bottom 110a and the downstream pond bottom 110b has an inclined surface 32. It flows down to the trough 31. In this way, the sand is settled in the space S1 (see FIG. 4) of the trough 31. The process of settling sand in the trough 31 corresponds to an example of a settling step.

  FIG. 5 is a timing chart showing drive timings and stop timings of pumps and nozzles installed in the solid-liquid separation facility 10 shown in FIGS. 1 and 2. The pump and nozzle shown in FIG. 5 are driven in parallel with the settling step described above. In FIG. 5, time elapses from the left to the right in the figure. Further, at the top of FIG. 5, driving (ON) and stopping (OFF) of the sand collecting water pump P2 are shown, and below that, driving (ON) and stopping (OFF) of the sand collecting pump P1 are shown. It is shown.

  FIG. 5 also shows the upstream first sand collecting nozzle 71a, the upstream second sand collecting nozzle 71b, the stirring nozzle 73, the pit sand collecting nozzle 72, the downstream first sand collecting nozzle 71c and the downstream shown in FIG. The driving and stopping of each of the side second sand collecting nozzles 71d are also shown. As described above, each of these nozzles (71a to 71d, 72, 73) is provided with one sand collecting valve V2, and in the timing chart of FIG. 5, each nozzle (71a to 71d, 72, 73) is provided. The state of each nozzle (71a-71d, 72, 73) is represented by the open / closed state of the sand collecting valve V2. That is, “fully open” represents the state of the nozzle when the sand collecting valve V2 is fully open, and “fully closed” represents the state of the nozzle when the sand collecting valve V2 is fully closed. As described above, in this embodiment, the opening and closing time of the sand collecting valve V2 is set to about 30 seconds, and the flow rate of water discharged from the nozzle is increased as the sand collecting valve V2 is opened from the fully closed state. When about 30 seconds elapse from the start of opening of the sand collecting valve V2 and the sand collecting valve V2 is fully opened, water at a flow rate adjusted by the sand collecting adjusting valve V1 is discharged from the nozzle. On the other hand, as the sand collecting valve V2 is closed from the fully open state, the flow rate of water discharged from the nozzle decreases, and when the sand collecting valve V2 enters the fully closed state after about 30 seconds from the start of closing the sand collecting valve V2, Water discharge from the nozzle stops.

  The drive of each pump (P1, P2) and each nozzle (71a-71d, 72, 73) shown in FIG. 5 is performed at a frequency of about three times per week, for example. As shown in FIG. 5, first, the sand collecting valve V2 of the stirring nozzle 73 is opened, and when about 15 seconds have elapsed since the opening of the sand collecting valve V2, the operation of the sand collecting water pump P2 is started. When about 15 seconds elapse from the start of operation of the sand collecting water pump P2, the sand collecting valve V2 of the stirring nozzle 73 is fully opened, and for example, every minute from the stirring nozzle 73 toward the suction port PO of the sand pump P1. About 500 to 2000 liters of water is discharged. By discharging the water, the sand accumulated around the suction port PO of the sand pump P1 can be stirred. Thereby, it is possible to prevent the suction port PO of the sand pump P1 from being clogged with sand, and it is possible to prevent the sand pump P1 that is subsequently started to be locked by so-called sand biting or the like. That is, the stirring nozzle 73 corresponds to an example of a stirring mechanism, and sand stirring by discharging water from the stirring nozzle 73 corresponds to an example of a stirring step.

  When about 15 seconds have elapsed since the sand collecting valve V2 of the stirring nozzle 73 is fully opened, the operation of the sand pump P1 is started. When the operation of the sand pump P1 is started, the sand accumulated in the sand collecting pit 4 is discharged by the sand pump P1 and conveyed to a sand settling separator or the like. Here, the sand discharged by the sand pump P <b> 1 is mainly sand that has settled in the sand collecting pit 4. The sand discharge by the sand pump P1 corresponds to an example of a discharge step. In the present embodiment, this discharging step ends after all of a plurality of downstream side moving steps to be described later are completed. That is, the discharge step of the present embodiment is a step that is executed during execution of a plurality of upstream movement steps described later, and is also executed during execution of a plurality of downstream movement steps.

  Water is discharged from the stirring nozzle 73 in the fully opened state for about 90 seconds, and then the sand collecting valve V2 of the stirring nozzle 73 is started to close. When about 30 seconds have elapsed from the start of closing of the sand collecting valve V2, the valve is fully closed and the discharge of water from the stirring nozzle 73 is stopped. Further, almost simultaneously with the start of closing of the sand collecting valve V2 of the stirring nozzle 73, opening of the sand collecting valve V2 of the upstream first sand collecting nozzle 71a is started. The sand collecting valve V2 of the upstream first sand collecting nozzle 71a is fully opened in about 30 seconds from the start of opening, and is 2000 liters per minute from the upstream first sand collecting nozzle 71a into the space S2 of the space forming member 8. Water is discharged. Thereby, the sand deposited in the upstream first trough 31a can be moved to the sand pit. The movement of sand by discharging water from the upstream first sand collection nozzle 71a corresponds to an example of an upstream movement step. After discharging water from the upstream first sand collecting nozzle 71a in a fully opened state for about 60 seconds, the upstream first sand collecting nozzle 71a starts closing the sand collecting valve V2.

  Almost simultaneously with the start of closing of the sand collecting valve V2 of the upstream first sand collecting nozzle 71a, the opening of the sand collecting valve V2 of the pair of pit sand collecting nozzles 72 provided in the sand collecting pit 4 is started. The sand collecting valve V2 of the pit sand collecting nozzle 72 is fully opened in about 30 seconds from the start of opening, toward each of the pair of pit sand collecting nozzles 72 toward the sand pump P1 disposed in the central portion in the pond width direction. 500 to 2000 liters of water are discharged every minute. Thereby, the sand in the sand collection pit 4 can be moved toward the sand pump P1. That is, the pit sand collection nozzle 72 corresponds to an example of an auxiliary movement mechanism, and the movement of sand in the sand collection pit 4 toward the sand pump P1 corresponds to an example of an auxiliary movement step. By this auxiliary moving step, the sand moved from the upstream first trough 31a into the sand collecting pit 4 by the upstream moving step is moved toward the sand pump P1 and efficiently discharged by the sand pump P1. it can. In the present embodiment, water is simultaneously discharged from the pair of pit sand collecting nozzles 72. However, in the auxiliary moving step after the upstream moving step is executed, the pit sand collecting nozzle 72 on the upstream first trough 31a side. Water may be discharged only from (the upper pit sand collecting nozzle 72 in FIG. 1). However, when water is simultaneously discharged from each of the pair of pit sand collecting nozzles 72, the sand moved in the sand collecting pit 4 is more likely to gather around the sand pump P1.

  After water is discharged from the discharge port 721 of the pit sand collection nozzle 72 in a fully open state for about 60 seconds, the sand collection valve V2 of the pit sand collection nozzle 72 starts to be closed. When about 30 seconds have elapsed since the start of closing, the sand collecting valve V2 of the pit sand collecting nozzle 72 is fully closed, and the discharge of water from the pit sand collecting nozzle 72 is stopped. Further, almost simultaneously with the start of closing of the sand collecting valve V2 of the pit sand collecting nozzle 72, opening of the sand collecting valve V2 of the upstream second sand collecting nozzle 71b is started. Similarly to the upstream first sand collecting nozzle 71a, 2000 liters of water per minute is discharged from the upstream first sand collecting nozzle 71a for about 60 seconds, and the sand accumulated in the upstream second trough 31b is collected in the sand collecting pit 4 Move to. The movement of sand by discharging water from the upstream second sand collection nozzle 71b also corresponds to an example of the upstream movement step. After water is discharged from the upstream second sand collecting nozzle 71b, water is discharged from the pit sand collecting nozzle 72 and the auxiliary movement step is executed.

  At the same time as the closing of the sand collecting valve V2 of the pit sand collecting nozzle 72, the opening of the sand collecting valve V2 of the downstream first sand collecting nozzle 71c is started. The downstream first sand collecting nozzle 71c also discharges 2000 liters of water per minute for about 60 seconds, and moves the sand accumulated in the downstream first trough 31c to the sand collecting pit 4. The movement of sand by discharging water from the downstream first sand collecting nozzle 71c corresponds to an example of a downstream movement step. After water is discharged from the downstream first sand collecting nozzle 71c, water is discharged from the discharge port 721 of the pit sand collecting nozzle 72 and the auxiliary movement step is executed.

  Next, 2000 liters of water per minute is discharged from the downstream second sand collecting nozzle 71d for about 60 seconds, and the sand accumulated in the downstream second trough 31d is moved to the sand collecting pit 4. The movement of sand by discharging water from the downstream second sand collecting nozzle 71d corresponds to an example of a downstream movement step. Thus, the downstream side movement step is a step that ends after all the plurality of upstream side movement steps are completed. Thereby, the sand which has moved to the downstream pond bottom 110b by the upstream side moving step can also be moved to the sand collecting pit 4 by the downstream side moving step, and the downstream first trough 31c and the downstream second trough 31d can be moved. Sand is hard to remain. Since the received sewage flows down from the upstream side to the downstream side, even if the downstream movement step is executed, the sand is difficult to move to the upstream pond bottom 110a. Therefore, the upstream movement step is performed after the downstream movement step is executed. Even if it is not executed, sand hardly remains in the upstream first trough 31a and the upstream second trough 31b. As a result, the sand remaining on the pond bottom 110 is reduced, and the sand contained in the received sewage can be efficiently separated.

  Further, in the present embodiment, the plurality of upstream movement steps start another upstream movement step after the completion of one upstream movement step so that the execution times of the upstream movement steps do not overlap with each other. The downstream side movement steps start another downstream side movement step after the end of one downstream side movement step so that the execution times of the downstream side movement steps do not overlap. That is, the time during which the sand collecting valves V2 of the four sand collecting nozzles 71 are open is shifted. For this reason, in the case of discharging 2,000 liters of water per minute from one sand collecting nozzle 71 as in the present embodiment, 4000 liters of water are discharged from the two sand collecting nozzles 71, 71 together. Never needed. As a result, it is not necessary to use a high-performance pump with a large maximum discharge amount for the sand collecting water pump P2, and the equipment cost can be reduced, and the electric motor of the sand collecting water pump P2 can be reduced in size and the running cost can be reduced. It becomes possible.

  Moreover, in this embodiment, the time when the sand collecting valve V2 of each nozzle is fully opened is shifted. Furthermore, the opening and closing time of the sand collecting valve V2 of each nozzle is set to be the same, and the opening of the sand collecting valve V2 of the other nozzle is started simultaneously with the start of closing of the sand collecting valve V2 of one nozzle. The sand collecting valve V2 of the other nozzles is set to the fully opened state when the sand collecting valve V2 of the other nozzle is fully closed. Also by this, the maximum discharge amount required for the sand collecting water pump P2 can be suppressed.

  After water is discharged from the downstream second sand collecting nozzle 71d, water is discharged from the pit sand collecting nozzle 72 and the auxiliary movement step is executed. That is, the auxiliary movement step is a step that ends after a downstream movement step that ends at least last among the plurality of downstream movement steps ends. By doing so, sand is prevented from moving to the sand collecting pit 4 by the downstream moving step after the auxiliary moving step is completed, and it is difficult for the sand to remain in the sand collecting pit 4. In addition, since the auxiliary movement step is executed every time when the plurality of upstream movement steps are completed and is also executed every time when the plurality of downstream movement steps are completed, a large amount of sand accumulates in the sand collecting pit 4. The sand is efficiently discharged from the sand pump P1. In addition, as shown by a dashed-dotted line in FIG. 5, water is also discharged from the discharge port of the stirring nozzle 73 in parallel with the discharge of water from the pit sand collecting nozzle 72, and the auxiliary movement step and the stirring step are performed in parallel. May be executed.

  In FIG. 5, the operation of the sand collecting water pump P <b> 2 is stopped substantially simultaneously with the time when the sand collecting valve V <b> 2 of the pit sand collecting nozzle 72 is started to be closed, and After the fully closed state, the operation of the sand pump P1 is stopped. By executing the above steps, the sand can be separated from the sewage received by the solid-liquid separation facility 10. Here, when the amount of sand that settles on the pond bottom 110 is large, there is a possibility that the sedimented sand cannot be sufficiently discharged even if one drive as shown in FIG. 5 is executed. For this reason, from the point in time when the opening of the sand collecting valve V2 of the upstream first sand collecting nozzle 71a indicated by D 'in FIG. 5 is started, the sand collecting valve V2 of the pit sand collecting nozzle 72 indicated by D in FIG. The cycle until the closing is started is defined as one cycle, and this cycle may be executed a plurality of times depending on the amount of sand settling. By doing so, even if the amount of sand that settles on the pond bottom 110 is large, the sedimented sand can be sufficiently discharged.

  In the present embodiment, the discharge amount from each nozzle is set to the above-described predetermined flow rate by adjusting the sand collecting adjustment valve V1, and the time for which the sand collecting valve V2 is fully opened is set to about 60 seconds. Within a range such as the maximum discharge amount of the installed sand collecting water pump P2, the discharge amount from each nozzle and the time during which the sand collecting valve V2 is fully opened may be adjusted during the trial operation.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope described in the claims.

In the solid-liquid separation method described above, the received liquid flows down in a direction orthogonal to the pond width direction of the settling basin, and the solid contained in the liquid is separated from the liquid.
A plurality of upstream grooves extending from the upstream side of the stacking unit provided with discharging means for discharging the solid toward the stacking unit and arranged in the pond width direction, and from the downstream side of the stacking unit A settling step for sinking the solid into a plurality of downstream grooves extending toward the accumulation portion and arranged in the pond width direction;
A plurality of upstream movement steps for moving solids settled in each of the plurality of upstream grooves to the accumulation part by a moving mechanism;
A plurality of downstream movement steps for moving solids settled in each of the plurality of downstream grooves to the accumulation unit by a movement mechanism;
A discharge step of discharging the solid in the stacking unit by the discharge means;
The downstream moving step is a step that ends after all the plurality of upstream moving steps are completed.

Further, the solid-liquid separation method described so far is a solid-liquid separation method in which the received liquid is caused to flow down in a flow-down direction perpendicular to the pond width direction of the settling basin and the solid contained in the liquid is separated from the liquid.
A plurality of upstream grooves extending from the upstream side in the flow-down direction toward the stacking part than the stacking part provided with discharging means for discharging the solid, and aligned in the pond width direction, and more than the stacking part A settling step for sinking the solid into a plurality of downstream grooves extending from the downstream side in the flow direction toward the accumulation portion and arranged in the pond width direction;
A plurality of upstream movement steps for moving solids settled in each of the plurality of upstream grooves to the accumulation part by a moving mechanism;
A plurality of downstream movement steps for moving solids settled in each of the plurality of downstream grooves to the accumulation unit by a movement mechanism;
A discharge step of discharging the solid in the stacking unit by the discharge means;
The downstream movement step is a step that ends after all the plurality of upstream movement steps are completed,
The plurality of upstream side movement steps and the plurality of downstream side movement steps are steps that are performed while the received liquid is caused to flow down in the flow-down direction.

  Here, some or all of the upstream movement steps of the plurality of upstream movement steps may start at the same time and end at the same time, may have different start points, or may have different end points. May be. Similarly, some or all of the plurality of downstream movement steps may start at the same time and end at the same time, or may have different start points or different end points. May be. Further, when a cycle including the plurality of upstream movement steps and the plurality of downstream movement steps is executed a plurality of times, the plurality of upstream movement steps may be executed after one cycle is completed. Further, the discharge step is started before the start of the plurality of upstream movement steps (for example, the start of the upstream movement step that is started first among the plurality of upstream movement steps). It may be a step that starts first) and ends after all of the plurality of downstream movement steps are completed. In other words, the discharging step may be executed during execution of the plurality of upstream movement steps, and may be executed during execution of the plurality of downstream movement steps. Moreover, the said upstream groove part and the said downstream groove part may be connected to the said integration | stacking part, and do not need to be connected.

  When the upstream side movement step is executed, the solid may move to the downstream groove part beyond the accumulation part, and the moved solid may settle in the downstream groove part. In the solid-liquid separation method, the downstream side moving step is a step that ends after all the plurality of upstream side moving steps are completed, that is, after the plurality of upstream side moving steps are completed, A move step is performed. For this reason, the solid that has moved to the downstream groove portion by the upstream side movement step can also be moved to the accumulation portion by the downstream side movement step, and the solid hardly remains in the downstream groove portion. In addition, since the received liquid flows down from the upstream side to the downstream side, even if the downstream side movement step is executed, the solid does not easily move beyond the accumulation portion to the upstream side groove portion. There is little possibility that the solid remains. The solid collected in the accumulation part is discharged by the discharge step, and the solid contained in the received liquid can be efficiently separated.

Further, in the solid-liquid separation method, the plurality of upstream movement steps may include another upstream movement step after one upstream movement step is completed so that execution times of the upstream movement steps do not overlap. Is the step to start,
The plurality of downstream movement steps may include other downstream movement steps after the completion of one downstream movement step so that execution times of the respective downstream movement steps do not overlap after the completion of the plurality of upstream movement steps. It may be a step of starting the downstream movement step.

  By doing so, the plurality of upstream movement steps and the plurality of downstream movement steps are not executed in parallel, and the discharge amount required for, for example, a sand collecting pump for supplying water to the movement mechanism. Is suppressed. As a result, there is no need to provide a high performance pump or the like having a large maximum discharge amount, and the equipment cost can be reduced. Further, for example, the motor of the pump can be reduced in size, and the running cost can be suppressed.

Furthermore, in the solid-liquid separation method, an auxiliary moving step of moving the solid in the stacking unit toward the discharge means by an auxiliary moving mechanism that moves the solid in the pond width direction,
The auxiliary movement step may be a step that ends after a downstream movement step that ends at the end of the plurality of downstream movement steps ends.

  That is, the auxiliary movement step may be a step that is performed one or more times and ends after the downstream movement step that ends at the end of the plurality of downstream movement steps ends.

  By the auxiliary movement step, the solid in the stacking unit can be moved toward the discharge means, and the solid can be efficiently discharged from the discharge means. In particular, if the auxiliary movement step is ended after the end of the downstream movement step that ends at the last of the plurality of downstream movement steps, the solid is placed in the stacking unit after the auxiliary movement step is completed. The solid that does not move and remains in the stacking portion can be reduced.

  In the solid-liquid separation method, the auxiliary movement step is performed every time the plurality of upstream movement steps are completed, and is also performed every time the plurality of downstream movement steps are completed. There may be.

  By doing so, it is possible to prevent the solid from being deposited in a large amount on the accumulation part, and to efficiently discharge the solid from the discharge means.

And a stirring step of stirring the solid deposited around the discharging means by a stirring mechanism,
The stirring step may be a step that starts before starting the discharging step.

  That is, the stirring step may be a step that is performed one or more times and starts at least before the discharging step is started.

  When the discharging means is a pump such as a sand pump, for example, the agitation step is executed, so that it is possible to prevent the pump from being locked due to so-called sand biting.

DESCRIPTION OF SYMBOLS 10 Solid-liquid separation facility 11 Sand basin 110,110a, 110b Pond bottom part 12 Pump well part 13 Connection part 31,31a, 31b, 31c, 31d Trough 311 Upper edge 32 Inclined surface 33 Connection part 4 Sand collection pit 71,71a, 71b , 71c, 71d Sand collecting nozzle 72 Pit sand collecting nozzle 73 Agitation nozzle 8 Space forming member 81 Suction port P1 Sand collection pump P2 Sand collection water pump R1 Sand pool R2 Flowing area S1, S2 Space

Claims (3)

In the solid-liquid separation facility that separates the solid contained in the liquid by flowing the received liquid in a flow direction perpendicular to the pond width direction of the settling basin,
A discharge means for discharging the solid provided in the stacking unit;
A plurality of upstream groove portions extending from the upstream side in the flow-down direction to the accumulation portion with respect to the accumulation portion and arranged in the pond width direction;
A plurality of downstream grooves extending from the downstream side of the flow-down direction to the stacking portion than the stacking portion and arranged in the pond width direction;
A plurality of upstream nozzles for discharging water for moving solids settled in each of the plurality of upstream grooves to the accumulation unit;
A plurality of downstream nozzles for discharging water for moving solids settled in each of the plurality of downstream grooves to the accumulation unit;
A stacking unit nozzle that discharges water for moving the solid moved to the stacking unit toward the discharging means in the stacking unit;
The upstream nozzle, the downstream nozzle, and the accumulation part nozzle all discharge water by opening an on-off valve provided in each,
Of the on-off valves provided in each of the upstream nozzle, the downstream nozzle, and the accumulation section nozzle, opening of the other on-off valve is started simultaneously with the start of closing of the on-off valve. Solid-liquid separation facility. The on-off valve has substantially the same length of the opening / closing time until the valve is fully opened from the fully closed state to the fully closed state.
The on-off valves provided in the upstream nozzle, the downstream nozzle, and the accumulation section nozzle, respectively, have a uniform length of the opening / closing time and a uniform length of the opening / closing time. The solid-liquid separation facility according to claim 1, wherein the facility is a solid-liquid separation facility.   The solid-liquid separation facility according to claim 1, wherein the upstream nozzle, the downstream nozzle, and the accumulation section nozzle discharge water supplied from a common pump.

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