JP6544558B2 - Solid-liquid separation method - Google Patents

Description

  The present invention relates to a solid-liquid separation method in which a received liquid is caused to flow down in a direction orthogonal to the pond width direction of a settling basin, and solids contained in the liquid are separated from the liquid.

  A solid-liquid separation facility equipped with a settling basin and a solid-liquid separation facility equipped with a settling basin are used as facilities for sewage treatment. Sedimentation basin is a sedimentation basin that receives sewage or sewage such as rainwater and settles sand contained in the sewage, moves sedimented sand to the sand collection pit, and lifts sand collected in the sand collection pit It is removed by sand pump. Sewage that has passed through the settling basin flows into the well of the pump and is discharged by the pumping pump installed in the well of the pump. In addition, the settling basin is a settling basin where sediments from which sand has been removed in the settling basin is removed and the sludge contained in the received sewage is sedimented, the sedimented sludge is moved to the sludge pit and collected in the sludge pit Sludge is removed by a sludge pump.

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

  The solid-liquid separation method implemented in the sedimentation basin described in Patent Document 1 performs a settling step of settling sand contained in the received sewage into a plurality of grooves, and then discharges water from the nozzle to make the grooves Carry out the moving step of moving the sand deposited inside. In this movement step, after the water is discharged from the most upstream nozzle in the upstream groove portion, the water is discharged from the middle nozzle, and the water is finally discharged from the most downstream nozzle. Thereby, the sand can be gradually moved from the upstream side to the downstream side toward the sedimentation pit. Further, also in the downstream groove portion, after the water is discharged from the most downstream nozzle, the water is discharged from the middle nozzle, and finally the water is discharged from the most upstream nozzle. Thereby, the sand can be gradually moved from the downstream side to the upstream side toward the sedimentation pit. As described above, the discharge amount of the sand collection pump for supplying water to the nozzles can be reduced by discharging the water in order toward the sedimentation pits instead of discharging the water from the plurality of nozzles at one time. it can.

JP, 2002-282609, A

  However, in the solid-liquid separation method described in Patent Document 1, 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 is not considered, As described in Document 1, the efficiency of the function of separating solids is the same as in the case of discharging water at one time from a plurality of nozzles.

  An object of the present invention is to provide a solid-liquid separation method capable of efficiently separating a solid contained in a received liquid.

A solid-liquid separation method according to the present invention for solving the above object is a solid-liquid separation method in which a received liquid is caused to flow down in a direction orthogonal to the pond width direction of the sedimentation part to separate solid contained in the liquid from the liquid. ,
A plurality of upstream-side grooves extending from the upstream side toward the accumulation unit from the upstream side with respect to the accumulation unit provided with discharge means for discharging the solid and aligned in the pond width direction, and the downstream side from the accumulation unit Settling the solids in a plurality of downstream grooves extending toward the accumulation section and aligned in the pond width direction;
A plurality of upstream moving steps for respectively moving the solid precipitated in each of the plurality of upstream grooves to the accumulation portion by a moving mechanism;
A plurality of downstream moving steps for moving the solid precipitated in each of the plurality of downstream grooves to the accumulation unit by the moving mechanism;
Discharging the solid in the accumulation unit by the discharging means;
Said downstream moving step, Ri step der ending after said all plural upstream moving step is completed,
Wherein the plurality of upstream moving step and said plurality of downstream moving step is characterized Step der Rukoto executing while flowing down in the direction of the receiving liquid perpendicular to the battery width direction.

  Here, some or all of the upstream movement steps of the plurality of upstream movement steps may be started simultaneously and may be completed simultaneously, or the start time may be made different, or the end time may be made different. May be Similarly, the downstream movement step of some or all of the plurality of downstream movement steps may be simultaneously started and ended simultaneously, or the start time may be different, or the end time may be different. May be When a cycle including the plurality of upstream movement steps and the plurality of downstream movement steps is performed a plurality of times, the plurality of upstream movement steps may be performed after one cycle is completed. Furthermore, the discharging step is started prior to the start of the plurality of upstream moving steps (e.g., the start of the upstream moving step started first of the plurality of upstream moving steps) The step may be started after the end of all of the plurality of downstream movement steps). That is, the discharging step may be a step which is performed during execution of the plurality of upstream movement steps and is also performed during execution of the plurality of downstream movement steps. Further, the upstream groove portion and the downstream groove portion may or may not be connected to the accumulation portion.

  When the upstream side moving step is performed, the solid may move to the downstream groove over the accumulation portion, and the moved solid may settle in the downstream groove. The downstream moving step in the solid-liquid separation method of the present invention is a step which is ended after all of the plurality of upstream moving steps are finished, that is, after all of the plurality of upstream moving steps are finished A downstream migration step is performed. Therefore, the solid moved to the downstream groove by the upstream moving step can also be moved to the accumulation unit by the downstream moving step, and the solid hardly remains in the downstream groove. Further, since the received liquid flows down from the upstream side to the downstream side, even if the downstream side moving step is performed, the solid does not easily move to the upstream side groove portion through the accumulation portion, and the solid is not There is little risk that the solid will remain. The solid collected in the accumulation unit is discharged by the discharging step, and the solid contained in the received liquid can be efficiently separated.

Further, in the solid-liquid separation method according to the present invention, the plurality of upstream movement steps may be performed after another upstream movement step is completed so that the execution times of the respective upstream movement steps do not overlap. Step to start the step,
The plurality of downstream movement steps may be performed after one of the downstream movement steps is completed so that the execution times of the respective downstream movement steps do not overlap after all of the plurality of upstream movement steps are completed. It may be a step of starting the downstream movement step.

  By doing this, the plurality of upstream-side moving steps and the plurality of downstream-side moving steps are not performed in parallel, and water is supplied to the moving mechanism, for example, the discharge amount necessary for sand collecting pump etc. Is reduced. As a result, it is not necessary to provide a high-performance pump or the like having a large maximum discharge amount, and equipment cost can be suppressed. Further, for example, the motor of the pump can be miniaturized, and the running cost can be suppressed.

Furthermore, in the solid-liquid separation method of the present invention, the method further includes an auxiliary moving step of moving the solid in the accumulation unit toward the discharge unit by an auxiliary moving mechanism that moves the solid in the pond width direction.
The auxiliary movement step may be a step which ends after the downstream movement step which ends at the end among the plurality of downstream movement steps is finished.

  That is, the auxiliary movement step may be performed one or more times, and is completed after at least the final downstream movement step of the plurality of downstream movement steps is completed.

  By the auxiliary moving step, the individual in the accumulation unit can be moved toward the discharging means, and the solid can be efficiently discharged from the discharging means. In particular, when the auxiliary moving step is ended after at least the final downstream moving step of the plurality of downstream moving steps is completed, the solid is placed in the stacking unit after the auxiliary moving step is ended. The solid which does not move and remains in the accumulation unit can be reduced.

  Further, in the solid-liquid separation method according to the present invention, the auxiliary moving step is executed each time the plurality of upstream moving steps are finished, and is also executed each time the plurality of downstream moving steps are finished. It may be a step.

  By doing this, it is possible to prevent the accumulation of a large amount of the individual on the accumulation part and efficiently discharge the solid from the discharging means.

The method further includes a stirring step of stirring the solid deposited around the discharging means by a stirring mechanism,
The stirring step may be a step starting before starting the discharging step.

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

  In the case where the discharge means is a pump such as a sand rising pump, for example, by performing the stirring step, it is possible to prevent a lock at the start of the pump by so-called sand biting or the like.

  According to the solid-liquid separation method of the present invention, it is possible to provide a solid-liquid separation method capable of efficiently separating the solid contained in the received liquid.

It is the top view which looked at the solid-liquid separation facility from upper direction. It is AA sectional drawing of the solid-liquid separation facility shown in FIG. It is BB sectional drawing of a solid-liquid separation facility shown in FIG. It is a figure which expands and shows the C section circled in FIG. It is a timing chart which shows the drive timing of a pump installed in the solid-liquid separation facility shown in Drawing 1 and Drawing 2, and a stop timing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The solid-liquid separation facility is used, for example, in a facility that carries out sewage treatment equipped with settling basins such as settling basins and settling basins. Moreover, the solid-liquid separation method is carried out, for example, in a solid-liquid separation facility provided with settling basins such as settling basins and settling basins. In the present embodiment, a solid-liquid separation facility provided with a sedimentation basin as a settling basin and a solid-liquid separation method implemented in a solid-liquid separation facility equipped with this sedimentation basin will be described as an example. Sedimentation basin is located upstream of the sewage treatment facility and removes sand contained in sewage or sewage such as 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 of the solid-liquid separation facility 10 shown in FIG. In addition, in FIG. 2, the sand raising pump P1, sand collection water pump P2, and the water pumping pump P3 which are not originally shown in AA sectional drawing are shown for the facilities of description.

  As shown in FIG. 1, the solid-liquid separation facility 10 is a rectangular pond having a rectangular shape in a plan view, including a sediment settling basin 11, a pump well 12, and a connecting portion 13 connecting the sediment settling 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 the longitudinal direction, and the short side direction may be referred to as the pond width direction. That is, in the present 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 waste water from the left side of the figure, and the received waste water slowly flows to the pump well 12 toward the right side of the figure (shown in FIGS. 1 and 2) See thick arrow). In FIGS. 1 and 2, the left side of the figure is the upstream side, the right side is the downstream side, and the right side 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 water surface of the sewage, and the position of the water surface WL is maintained at the set water level. Sand contained in the sewage settles in the sedimentation basin 11 while the sewage slowly flows toward the pump well 12. The sedimentation basin 11 is a pond for settling sand contained in the sewage received by the solid-liquid separation facility 10, and corresponds to an example of a settling basin. Sewage that has passed through the sediment settling basin 11 flows over the connecting portion 13 into the pump well 12 and is discharged by the pump P3 installed in the pump well 12. In the sediment settling basin 11, a region below the connecting portion 13 forms a sand pool R1 for storing sand, and the sewage flows into a region above the sand pool R1. That is, the area | region from the connection part 13 to the water surface WL forms the downflow area | region R2 into which sewage flows. The area of the surface obtained by cutting the flow-down region R2 in the width direction corresponds to the flow-down cross-sectional area.

  A dust collector 2 is provided upstream of the settling basin 11. The dust remover 2 is for removing stone blocks, residue and the like having a predetermined size or more out of the solids contained in the waste water which is going to flow into the sedimentation basin 11. The dust remover 2 has an endless chain 21, a plurality of rake 22 attached to the endless chain 21 at intervals, and a filtration screen 23 submerged in water. The endless chain 21 is provided in a state of being erected obliquely on both sides in the width direction of the solid-liquid separation facility 10 and, as shown in FIG. 2, is wound around the ground sprocket 211 and the pond bottom sprocket 212. It is done. When the endless chain 21 is driven, the rake 22 moves in and out of the water. The filtration screen 23 is disposed downstream of the endless chain 21. In the filtration 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 solids having a size equal to or greater than the predetermined interval. In the present embodiment, vertically extending bars are arranged at intervals of 75 mm. The solids blocked by the filtration screen 23 are scraped off by the lake 22, and the scraped solids are placed on the ground side on a conveying means such as a belt conveyor (not shown).

  As shown in FIG. 1 and FIG. 2, the sedimentation basin 11 provided on the downstream side of the dust collector 2 has an upstream pond bottom 110 a, sand collecting pits 4 and a downstream side provided in the order from the upstream side to the downstream side. A pond bottom 110b is provided. Hereinafter, when it is not necessary to distinguish between the upstream pond bottom 110a and the downstream pond bottom 110b, it may be collectively referred to as the pond bottom 110. The sand which has settled on the pond bottom portion 110 moves to the sand collecting pit 4 by the water discharged from the sand collecting nozzle 71 described later. As a result, the sand in the sewage flowing into the sediment settling basin 11 is collected in the sand collecting pit 4. That is, the sand collection pit 4 corresponds to an example of the accumulation unit, and sand in the sewage flowing into the sedimentation basin 11 corresponds to an example of a solid contained in the received liquid. Specifically, in the upstream pond bottom portion 110a, the direction from the upstream side toward the sand collecting pit 4 (see the thin arrow in the right direction shown in FIGS. 1 and 2) is the sand moving direction, and the downstream pond bottom portion 110b Then, the direction from the downstream side toward the sand collecting pit 4 (see the left thin arrow shown in FIG. 1 and FIG. 2) is the sand moving direction. Therefore, in the upstream pond bottom portion 110a, the downflow direction (thick arrow in the figure) coincides with the movement direction (thin arrow in the figure), but in the downstream pond bottom portion 110b, the downflow direction (thick arrow in the figure) and the movement direction (The thin arrows in the figure) are in the opposite direction.

  As shown in FIG. 1, two troughs 31, 31 extending in the longitudinal direction and aligned in the pond width direction are provided in the upstream pond bottom portion 110 a. Of the two troughs 31 and 31 provided in the upstream pond bottom 110a, in the following description, the trough 31 located on the upper side of FIG. 1 is referred to as the upstream first trough 31a, and is located on the lower side of FIG. The troughs 31 may be referred to as upstream second troughs 31b. Moreover, the two troughs 31 and 31 which extended in the longitudinal direction and were located in a line with the pond width direction are provided also in the downstream pond bottom part 110b. Of the two troughs 31 and 31 provided in the downstream pond bottom 110b, in the following description, the trough 31 located on the upper side of FIG. 1 is referred to as the downstream first trough 31c, and is located on the lower side of FIG. The trough 31 may be referred to as a downstream second trough 31 d in some cases. The troughs 31 correspond to a plurality of grooves extending in a direction perpendicular to the pond width direction and aligned in the pond width direction. Further, the first upstream trough 31a and the second upstream trough 31b correspond to a plurality of upstream grooves, and the first downstream trough 31c and the second downstream trough 31b correspond to a plurality of downstream grooves. In the present embodiment, each of the troughs 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 which are inclined downward toward the troughs 31 from both sides in the pond width direction. The pair of inclined surfaces 32 and 32 are surfaces which 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, a sand collecting nozzle 71 is provided for each of the plurality of troughs 31. Specifically, the upstream first collecting sand nozzle 71a is provided on the upstream side of the upstream first trough 31a, and the upstream second collecting sand nozzle 71b is provided on the upstream side of the upstream second trough 31b. ing. Further, a downstream first water collecting nozzle 71c is provided downstream of the downstream first trough 31c, and a downstream second water collecting nozzle 71d is provided downstream of the downstream second trough 31d. FIG. 2 shows the upstream first collecting sand nozzle 71a disposed upstream of the upstream first trough 31a, and the downstream first collecting sand nozzle 71c disposed downstream of the downstream first trough 31c. ing.

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

  As shown in FIG. 1, the sand gathering pit 4 has a flat surface portion 41 provided at the central portion in the pond width direction, and a pair of inclined surface portions 42 and 42 respectively provided on both sides of the flat surface portion 41 in the pond width direction. doing. The flat surface portion 41 is formed of a flat surface having a rectangular shape in a plan view, and the sand pump P1 is disposed at the central portion of the flat surface portion 41. As shown in FIG. 2, the sand raising pump P <b> 1 includes a suction port PO located at a predetermined height from the flat surface portion 41. The sand raising pump P1 sucks the sand collected in the sand collecting pit 4 from the suction port PO, and conveys the sand to a sedimentation separator 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 rising sand pump P1 disposed on the flat surface portion 41. I will The area of the inclined surface portion 42 and the inclination angle thereof are set in accordance with the length of the sand collecting pit 4 in the pond width direction and the like. 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 relatively large, and the inclination angle is set relatively large. On the contrary, when the length in the pond width direction of the sand collecting pit 4 is short and the settled sand can be sufficiently moved around the sand raising pump P1 by the water discharged from the pit collecting nozzle 72 described later. In some cases, the inclined surface portion 42 may be omitted. In the present embodiment, the inclination angle of the inclined surface portion 42 is set larger than the inclination angle of the inclined surface 32 connected to the trough 31.

  As shown in FIG. 1, inside the sand collecting pit 4, a pair of pit collecting nozzles 72, 72 disposed along the pair of inclined surface portions 42, 42 are provided. Each of the pit collecting nozzles 72 has two discharge ports 721 which are bifurcated and spaced apart in the longitudinal direction. The discharge ports 721 discharge water along the inclined surface portion 42 toward the sand raising pump P1 disposed at the center in the width direction of the sand collecting pit 4. As a result, the sand collected in the sand collecting pit 4 is collected around the sand raising pump P1.

  As shown in FIG. 1, a pair of stirring nozzles 73, 73 are further provided in the sand collecting pit 4. In FIG. 1, in order to simplify the drawing, only the stirring nozzle 73 is shown, and the water supply branch pipe connected to the stirring nozzle 73 is omitted. Moreover, in FIG. 2, stirring nozzle 73 itself is also abbreviate | omitted. The pair of stirring nozzles 73, 73 are disposed around the sand raising pump P1, discharge water toward the periphery of the suction port PO (see FIG. 2) of the sand rising pump P1, and around the suction port PO. It disturbs deposited sand. As a result, the suction port PO (see FIG. 2) of the sand raising pump P1 is prevented from being blocked, and so-called locking at the start of the pump due to so-called sand biting or the like is prevented. When the length of the sand collecting pit 4 in the pond width direction is short, either one of the pit collecting nozzle 72 and the stirring nozzle 73 is omitted, and the pit collecting sand nozzle 72 and the stirring nozzle 73 are selected by the other. A configuration in which both functions are provided can also be adopted.

  As shown in FIG. 1 and FIG. 2, the downstream pond bottom 110b and the pump well 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 and It becomes a boundary with the flowing down area R2 (see FIG. 2). The pump well 12 stores dirty water 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 2 is connected to each nozzle by a water supply main 741 and a plurality of water supply branch pipes 742. In FIG. 2, it is illustrated that the sand collecting water pump P2 is connected to the upstream first water collecting nozzle 71a, the downstream first water collecting nozzle 71c, and the pit collecting nozzle 72 on one side. Although not shown, the sand collecting water pump P2 is also connected to the upstream second collecting sand nozzle 71b, the downstream second collecting sand nozzle 71d, and the pit collecting sand 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 control valve V1 and a sand collection valve V2. The sand collection control valve V1 adjusts the flow rate of water supplied to each nozzle, and is constituted by, for example, a manual ball valve. The sand collection valve V2 is opened to supply water to each nozzle, and closed to stop the supply of water to each nozzle, and is constituted by, for example, an electric ball valve. In the present embodiment, the open / close time of the sand collection valve V2 is set to 30 seconds. For this reason, when opening of the sand collection valve V2 is started from the fully closed state, the flow rate of water discharged from the nozzle connected to the sand collection valve V2 gradually increases, and becomes fully open in about 30 seconds. . When the sand collecting valve V2 is fully opened, water of a flow rate adjusted by the sand collecting adjusting valve V1 is discharged from the nozzle. In addition, when closing of the sand collection valve V2 is started 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 water discharge from the nozzle is completely stopped. The opening and closing time of the sand collecting valve V2 can be set appropriately, and the opening and closing time may be made different for each of the sand collecting nozzle 71, the pit collecting sand nozzle 72 and the stirring nozzle 73. In the present embodiment, a configuration in which one sand collecting adjustment valve V1 and one sand collecting valve V2 are provided for the pair of pit collecting nozzles 72, 72 is adopted. Thereby, water is discharged from the pair of pit collection nozzles 72, 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 one sand collecting control valve V1 and sand collecting valve V2 are provided also with respect to a pair of stirring nozzles 73 and 73 is employ | adopted. Of course, the sand collection control valve V1 and the sand collection valve V2 may be provided in each of the pair of pit collection nozzles 72, 72, or the sand collection adjustment valve V1 and the collection valve in each of the pair of stirring nozzles 73, 73 V2 may be provided.

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

  As shown in FIG. 3, each of the downstream first trough 31 c and the downstream second trough 31 d has a pair of upper edges 311, 311 defining an opening, and obliquely upward from each of the pair of upper edges 311, 311. An inclined surface 32 extending to the In FIG. 3, the inclined surface 32 extending from the left upper edge 311 of the downstream first trough 31 c is connected to the side wall 34 of the sedimentation basin 11 and is inclined surface 32 extending from the right upper edge 311 of the downstream second trough 31 d. Also, it is connected to the side wall 34 of the settling basin 11. Further, the inclined surface 32 extending from the upper right edge 311 of the downstream first trough 31 c and the inclined surface 32 extending from the upper left edge 311 of the lower left second trough 31 d are connected at the center in the pond width direction 33 are formed. In the present embodiment, the connecting portion 33 is constituted by a sharp portion where the inclined surface 32 and the inclined surface 32 abut, for example, as shown by an alternate long and short dash line in FIG. In the above, the connection portion 33 may be configured as a flat portion, or may be a connection portion 33 in which the inclined surface 32 and the inclined surface 32 are connected in an arc shape. Sand deposited on the downstream pond bottom 110b flows down 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 and 311 of the troughs 31, sedimented sand is deposited on the inclined surfaces 32 even when the sedimentation width of the settling 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, a mode in which three or more troughs 31 are provided side by side in the pond width direction is required to prevent sand from being deposited on the inclined surface 32. In some cases. Even in this case, since the inclined surface 32 is provided, the number of the troughs 31 can be reduced by the amount of the inclined surface 32. Thereby, the number of sand collecting nozzles 71 etc. as a movement mechanism is also suppressed, and the increase in construction cost can also be suppressed.

  Furthermore, since the height of the connection portion 33 is equal to or less than the height of the connection portion 13, the inclined surface 32 does not block the flow-down region R <b> 2 above the connection portion 13. As a result, it is possible to prevent the falling cross-sectional area from being reduced and the collection efficiency to be reduced. That is, the decrease in the flow-through cross-sectional area makes the flow speed of the sewage flowing through the sedimentation tank 11 faster, and the problem that the sand becomes difficult to settle in the pond bottom 110 does not occur. Further, by suppressing the height of the connection portion 33 to be equal to or less than the height of the connecting portion 13, when, for example, the inclined surface 32 is formed of concrete, an increase in the amount of casting can also be suppressed.

  In the present embodiment, the inclination angle (the angle (elevation angle) with respect to the horizontal surface) 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 in the range of 15 degrees to 40 degrees. If the inclination angle α is less than 15 degrees, sand deposited on the inclined surface 32 may not flow down to the trough 31 along the inclined surface 32 and may be deposited on the inclined surface 32. On the other hand, in order to move the sand which has settled on the inclined surface 32 to the trough 31, it is sufficient to set the inclination angle α to 45 degrees, and when the inclination angle α exceeds 45 degrees, the concrete forming the inclined surface 32 It is not preferable because the amount of the cast irons greatly increases. Further, in order to sufficiently reduce the amount of concrete to form the inclined surface 32, the inclination angle α may be 40 degrees or less. In the present embodiment, although the inclination angles α of the plurality of inclined surfaces 32 are set to be substantially the same, for example, the inclination angles α of the inclined surfaces 32 connected to the side wall 34 are connected to other inclined surfaces 32. The inclination angle α may be made different for each inclined surface 32, such as being larger than the inclination angle α of the inclined surface 32 forming the connection portion 33.

  Next, the configuration of the trough 31, the sand collecting nozzle 71, and the space forming member 8 will be described in detail with reference to FIG. FIG. 4 is an enlarged view of a circled portion C in FIG. Here, the downstream first trough 31 c and the downstream first sand collecting nozzle 71 c will be described as an example. In FIG. 4, the direction from the back to the front of the paper surface is the sand movement direction.

  The trough 31 of the present embodiment has a shape with a total length of 10 m, a diameter of 300 mm, and a thickness of about 3 mm and is cut about 1/3 on the upper side of a stainless steel cylinder and is opened upward. Moreover, the trough 31 has an inner circumferential surface 312, and a space S1 defined by the inner circumferential surface is formed. In addition, the cross-sectional shape of the trough width direction of the trough 31 is not restricted to circular arc shape, U shape, V shape, etc. may be sufficient.

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

  The water collecting branch pipe 742 is connected to the rear end portion of the sand collecting nozzle 71, and the discharge port 711 is provided 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 via the water supply main pipe 741 and the water supply branch pipe 742 by the sand collecting water pump P2, the water supplied to the sand collecting nozzle 71 Is discharged from the discharge port 711. In the present embodiment, the discharge flow velocity 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. Further, 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. When the total length of the trough 31 is set to about 5 m, the flow rate of water discharged from the discharge port 711 is adjusted to about 1500 liters per minute. As described above, the flow rate of water discharged from the discharge port 711 is appropriately adjusted in accordance with the total length of the trough 31 and the like. In the present embodiment, the waste water stored in the pump well 12 is used as the water discharged from the discharge port 711. However, other waste water received in the waste water treatment site may be used. Other water may be used.

  When water is discharged from the discharge port 711 of the sand collection nozzle 71 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 the inside of the trough 31 (space S1 The sand deposited on the) is sucked into the space S2 from the suction port 81 as indicated by the curved arrow shown in FIG. Further, in the space S2 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 hard to get out of the space forming member 8 in the part where the pressure difference is generated, and the rolling up of the sand is suppressed. Therefore, it is possible to suppress the rolling up of the sand while moving the sand sufficiently. That is, the sand collecting nozzle 71 and the space forming member 8 correspond to an example of the moving mechanism.

  Subsequently, the solid-liquid separation method implemented in the solid-liquid separation facility 10 described so far will be described. First, the steps up to the settling step will be described. In the solid-liquid separation facility 10, the process to the settling step is continued while receiving the sewage.

  When the sewage flowing into the solid-liquid separation facility 10 passes through the dust collector 2 shown in FIGS. 1 and 2, debris and the like mixed in the sewage are removed. The waste water that has passed through the dust collector 2 reaches the upstream end of the upstream pond bottom portion 110a, and further flows toward the pump well 12 through the downflow region R2 shown in FIG. While the sewage flows to the pump well 12, much of the sand contained in the sewage settles in the sand pool R1. Some sand settles in the sand collection pit 4, some sand settles in the upstream pond bottom 110a and the downstream pond bottom 110b, and sand settled in the upstream pond bottom 110a and the downstream pond bottom 110b is the slope 32 It flows down to the trough 31 along. Thus, the sand settles in the space S1 (see FIG. 4) of the trough 31. The step of settling the sand in the trough 31 corresponds to an example of the 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 the nozzle shown in FIG. 5 are driven in parallel with the settling step described above, and in FIG. 5, time passes from the left to the right of the figure. In addition, the driving (ON) and stopping (OFF) of the sand collecting water pump P2 are shown at the top of FIG. 5, and the driving (ON) and stopping (OFF) of the sand raising pump P1 are shown below it. It is shown.

  Further, in FIG. 5, the upstream first collecting nozzle 71a, the upstream second collecting nozzle 71b, the stirring nozzle 73, the pit collecting nozzle 72, the downstream first collecting nozzle 71c and the downstream shown in FIG. The driving and stopping of each of the side second collecting sand nozzles 71 d are also shown. As described above, one sand collecting valve V2 is provided for each of these nozzles (71a to 71d, 72, 73), and each nozzle (71a to 71d, 72, 73) is provided in the timing chart of FIG. The state of each of the nozzles (71a to 71d, 72, 73) is represented by the open / close state of the sand collection valve V2. That is, "full open" represents the state of the nozzle when the sand collection valve V2 is in the fully open state, and "full close" represents the state of the nozzle when the sand collection valve V2 is in the fully closed state. As described above, in the present embodiment, the open / close time of the sand collection valve V2 is set to about 30 seconds, and the flow rate of water discharged from the nozzle as the sand collection valve V2 is released from the fully closed state is 30 seconds after the start of the opening of the sand collection valve V2, when the sand collection valve V2 is fully opened, water of a flow rate adjusted by the sand collection control 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 about 30 seconds after the start of closing the sand collecting valve V2, the sand collecting valve V2 becomes fully closed, Discharge of water from the nozzle stops.

  The driving of the pumps (P1, P2) and the nozzles (71a to 71d, 72, 73) shown in FIG. 5 is executed, for example, at a frequency of about three times a week. As shown in FIG. 5, first, opening of the sand collecting valve V2 of the stirring nozzle 73 is started, and after about 15 seconds have elapsed from the start of opening of the sand collecting valve V2, operation of the sand collecting water pump P2 is started. About 15 seconds after 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 periphery of the suction port PO of the sand raising pump P1. About 500 liters to 2000 liters of water is discharged. The discharge of the water can stir the sand deposited around the suction port PO of the sand raising pump P1. As a result, it is possible to prevent the suction port PO of the sand raising pump P1 from being blocked by sand, and to prevent lock of the sand raising pump P1 whose operation is subsequently started due to so-called sand bite or the like. That is, the stirring nozzle 73 corresponds to an example of a stirring mechanism, and the stirring of sand by the discharge of water from the stirring nozzle 73 corresponds to an example of a stirring step.

  About 15 seconds after the sand collecting valve V2 of the stirring nozzle 73 is fully opened, the operation of the sand raising pump P1 is started. When the operation of the sand pumping pump P1 is started, the sand deposited in the sand collecting pit 4 is discharged by the sand pumping pump P1 and is conveyed to a sedimentation separator or the like. Here, the sand discharged by the sand raising pump P1 is sand settled mainly in the sand collecting pit 4. The discharge of sand by the sand raising pump P1 corresponds to an example of the discharge step. In this embodiment, the discharging step ends after all of the plurality of downstream movement steps described later are completed. That is, the discharging step of this embodiment is a step which is performed during execution of a plurality of upstream movement steps described later, and is also performed during execution of the plurality of downstream movement steps.

  After the water is discharged for about 90 seconds in the fully open state from the stirring nozzle 73, the closing of the sand collecting valve V2 of the stirring nozzle 73 is started. About 30 seconds after the start of closing of the collecting valve V2, the state is fully closed, and the discharge of water from the stirring nozzle 73 is stopped. Further, substantially simultaneously with the start of closing of the sand collection valve V2 of the stirring nozzle 73, the opening of the sand collection valve V2 of the upstream first water collecting nozzle 71a is started. The sand collection valve V2 of the first upstream sand collection nozzle 71a becomes fully open in about 30 seconds from the start of opening, and 2000 liters per minute from the first upstream sand collection nozzle 71a in 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 sedimentation pit. The movement of sand by discharging water from the upstream first sand collection nozzle 71a corresponds to an example of the upstream movement step. After discharging the water for about 60 seconds in the fully open state from the upstream first collecting nozzle 71a, the closing of the collecting valve V2 of the upstream first collecting nozzle 71a is started.

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

  After the water is discharged for about 60 seconds in a fully open state from the discharge port 721 of the pit collecting nozzle 72, the closing of the collecting valve V2 of the pit collecting nozzle 72 is started. About 30 seconds after the start of closing, the sand collecting valve V2 of the pit collecting nozzle 72 is fully closed, and the water discharge from the pit collecting nozzle 72 is stopped. Further, substantially simultaneously with the start of closing of the sand collecting valve V2 of the pit collecting nozzle 72, the opening of the sand collecting valve V2 of the upstream second collecting nozzle 71b is started. Similar to the first upstream sand collection nozzle 71a, water of about 2,000 liters per minute is discharged from the upstream first sand collection nozzle 71a for about 60 seconds, and sand deposited in the second upstream trough 31b is collected sand pit 4 Move to The movement of sand by discharging the water from the upstream second collecting nozzle 71b also corresponds to an example of the upstream movement step. After the water is discharged from the upstream second collecting nozzle 71b, the water is discharged from the pit collecting nozzle 72 to execute the auxiliary moving step.

  Almost simultaneously with the start of closing of the sand collecting valve V2 of the pit collecting nozzle 72, opening of the sand collecting valve V2 of the downstream first collecting nozzle 71c is started. The downstream side first sand collection nozzle 71 c also discharges 2000 liters of water per minute for about 60 seconds to move sand deposited in the downstream first trough 31 c to the sand collection pit 4. The movement of the sand by discharging the water from the downstream side first sand collection nozzle 71c corresponds to an example of the downstream side movement step. After the water is discharged from the downstream side first sand collection nozzle 71c, the water is discharged from the discharge port 721 of the pit collection nozzle 72 to execute the auxiliary movement step.

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

  Furthermore, in the present embodiment, the plurality of upstream movement steps start another upstream movement step after one upstream movement step is completed so that the execution times of the respective upstream movement steps do not overlap, The downstream-side moving step starts another downstream-side moving step after completion of one downstream-side moving step so that the execution times of the respective downstream-side moving steps do not overlap. That is, the time during which the sand collecting valve V2 of each of the four sand collecting nozzles 71 is open is shifted. For this reason, in the case of discharging water at 2000 liters per minute from one collecting nozzle 71 as in the present embodiment, discharge of water at 4000 liters per minute is combined from the two collecting nozzles 71, 71. It will never be necessary. As a result, it is not necessary to adopt a high-performance pump having a large maximum discharge amount for the sand collecting water pump P2, and the equipment cost can be reduced, the motor of the sand collecting water pump P2 can be miniaturized, and the running cost is suppressed. It also becomes possible.

  Moreover, in this embodiment, the time when the sand collection valve V2 of each nozzle is fully opened is shifted. Furthermore, one nozzle is set by setting the opening / closing time of the sand collecting valve V2 of each nozzle identically and starting the closing of the sand collecting valve V2 of the other nozzle simultaneously with the start of closing of the sand collecting valve V2 of one nozzle. When the collecting valve V2 is fully closed, the collecting valve V2 of the other nozzle is fully opened. Also by this, it is possible to reduce the maximum discharge amount required for the sand collection water pump P2.

  After the water is discharged from the downstream second collecting nozzle 71d, the water is discharged from the pit collecting nozzle 72 to execute the auxiliary moving step. That is, the auxiliary movement step is a step which ends after at least the final downstream movement step of the plurality of downstream movement steps is completed. In this way, it is possible to prevent the sand 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 each time the plurality of upstream movement steps are completed, and is also performed each time the plurality of downstream movement steps is completed, a large amount of sand is accumulated in the sand collecting pit 4 Can be efficiently discharged from the sand raising pump P1. In addition, as shown by the alternate long and short dash 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 collecting nozzle 72, and the auxiliary movement step and the stirring step are performed in parallel. It may be executed.

  The operation of the sand collecting water pump P2 is stopped substantially simultaneously with the time when the closing of the sand collecting valve V2 of the pit collecting nozzle 72 is started, which is indicated by D in FIG. 5, the collecting valve V2 of the pit collecting nozzle 72 After the fully closed state, the operation of the sand raising pump P1 is stopped. By performing the above steps, sand can be separated from the waste water received by the solid-liquid separation facility 10. Here, when there is a large amount of sand settling in the pond bottom portion 110, there is a possibility that the sedimented sand can not be sufficiently discharged even if one drive as shown in FIG. 5 is performed. Therefore, from the time point when opening of the sand collecting valve V2 of the upstream first water collecting nozzle 71a is started, which is indicated by D 'in FIG. 5, the dust collecting valve V2 of the pit collecting nozzle 72 indicated by D in FIG. This cycle may be performed a plurality of times depending on the amount of sand to be settled, with one cycle until the closure is started. In this way, even when the amount of sand settling in the pond bottom 110 is large, the settled sand can be sufficiently discharged.

  In the present embodiment, the discharge amount from each nozzle is adjusted by the sand collection adjustment valve V1 to set the above-mentioned predetermined flow rate, and the time of the sand collection valve V2 is set to about 60 seconds. The amount of discharge from each nozzle or the time for which the sand collection valve V2 is fully open may be adjusted at the time of trial operation within the range of the maximum discharge of the sand collection water pump P2 installed and the like.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.
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 direction orthogonal to the width direction of the sedimentation basin portion to separate the solid contained in the liquid from the liquid.
A plurality of upstream-side grooves extending from the upstream side toward the accumulation unit from the upstream side with respect to the accumulation unit provided with discharge means for discharging the solid and aligned in the pond width direction, and the downstream side from the accumulation unit Settling the solids in a plurality of downstream grooves extending toward the accumulation section and aligned in the pond width direction;
A plurality of upstream moving steps for respectively moving the solid precipitated in each of the plurality of upstream grooves to the accumulation portion by a moving mechanism;
A plurality of downstream moving steps for moving the solid precipitated in each of the plurality of downstream grooves to the accumulation unit by the moving mechanism;
Discharging the solid in the accumulation unit by the discharging means;
The downstream movement step is a step which ends after all of the plurality of upstream movement steps are completed.

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

Claims (5)

In a solid-liquid separation method in which a received liquid is caused to flow down in a flowing direction orthogonal to the pond width direction of the sedimentation section to separate a solid contained in the liquid from the liquid,
A plurality of upstream grooves extending from the upstream side of the flow-down direction toward the accumulation portion and arranged in the pond width direction with respect to the accumulation portion provided with the discharge means for discharging the solid, and the accumulation portion Settling the solids in a plurality of downstream grooves extending from the downstream side in the flow direction toward the accumulation portion and aligned in the pond width direction;
A plurality of upstream moving steps for respectively moving the solid precipitated in each of the plurality of upstream grooves to the accumulation portion by a moving mechanism;
A plurality of downstream moving steps for moving the solid precipitated in each of the plurality of downstream grooves to the accumulation unit by the moving mechanism;
Discharging the solid in the accumulation unit by the discharging means;
Said downstream moving step, Ri step der ending after said all plural upstream moving step is completed,
Wherein the plurality of upstream moving step and said plurality of downstream moving step, solid-liquid separation method comprising steps der Rukoto executing while flowing down the receiving liquid in the flow-down direction. The plurality of upstream movement steps are steps of starting another upstream movement step after one of the upstream movement steps is completed so that the execution times of the respective upstream movement steps do not overlap.
The plurality of downstream movement steps may be performed after one of the downstream movement steps is completed so that the execution times of the respective downstream movement steps do not overlap after all of the plurality of upstream movement steps are completed. The solid-liquid separation method according to claim 1, which is a step of starting a downstream side moving step. And an auxiliary moving step of moving the solid in the accumulation unit toward the discharging unit by an auxiliary moving mechanism that moves the solid in the pond width direction;
The solid-liquid separation method according to claim 1 or 2, wherein the auxiliary movement step is a step which ends after the downstream movement step which ends at the end among the plurality of downstream movement steps is finished.   The auxiliary movement step is performed each time the plurality of upstream movement steps are completed, and is also performed each time each of the plurality of downstream movement steps is completed. Solid-liquid separation method described. It has a stirring step of stirring the solid deposited around the discharge means by a stirring mechanism,
The solid-liquid separation method according to any one of claims 1 to 4, wherein the stirring step is a step started before starting the discharging step.

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