Solid-liquid separation system

Abstract

To provide a solid-liquid separation system that can increase processing capacity even in shallow final sedimentation tanks. [Solution] A solid-liquid separation system 100 is installed in the final sedimentation tank P of a sewage treatment plant, and comprises an inclined plate device 1 having a plurality of inclined plates 41 that are parallel to the flow direction D of the water to be treated and inclined with respect to the horizontal direction.

Description

[Technical Field]

[0001] This invention relates to a solid-liquid separation system. [Background technology]

[0002] To increase the treatment capacity of the final sedimentation tank in existing sewage treatment plants where a certain amount of sewage flows in or more, it has been proposed to introduce an upward-flow type inclined plate device below the overflow weir at the end of the final sedimentation tank (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-60931 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, in relatively shallow final sedimentation tanks, introducing an inclined plate device below the overflow weir would result in insufficient clearance with the existing sludge scraping equipment. This can hinder maintenance of the sludge scraping machine, and in many cases, the introduction of an inclined plate device to the final sedimentation tank is not permitted.

[0005] The present invention aims to provide a solid-liquid separation system that can increase processing capacity even in a final sedimentation tank with a shallow water depth. [Means for solving the problem]

[0006] The solid-liquid separation system according to this disclosure is a solid-liquid separation system to be installed in the final sedimentation tank of a sewage treatment plant, and comprises an inclined plate device having a plurality of inclined plates that are parallel to the direction of the water flow of the water to be treated and inclined with respect to the horizontal direction.

[0007] Multiple inclined plates, positioned parallel to the flow direction of the treated water, do not need to be placed below the overflow weir. Therefore, they can be installed even in shallow final sedimentation tanks, thereby increasing the water treatment capacity.

[0008] The inclined plates may be positioned so that their angle with respect to the horizontal is between 20 degrees and 80 degrees.

[0009] This allows for an increase in the settlement area and makes it easier for the sludge to slide off.

[0010] The inclined plate device may have multiple inclined plate units arranged in at least one of the width direction, vertical direction, and water flow direction of the final sedimentation tank. Multiple inclined plates may be arranged in multiple inclined plate units.

[0011] This allows for the placement of the required number of inclined plate units in the width direction, vertical direction, or flow direction, depending on the shape and dimensions of the final sedimentation tank, thus making it easy to install an inclined plate device of the appropriate size for the final sedimentation tank.

[0012] The spacing between adjacent inclined plates in an inclined plate unit located on the inflow side of the water to be treated may be wider than the spacing between adjacent inclined plates in an inclined plate unit located on the outflow side of the water to be treated.

[0013] This makes it possible to suppress blockage of the inlet-side inclined plate by sludge, even when treated water with a high concentration of suspended solids is inflow.

[0014] The solid-liquid separation system may further include a scum discharge device for discharging scum. The inclined plate device may be positioned on the inflow side of the treated water relative to the scum discharge device.

[0015] Because the inclined plate device is positioned on the inflow side of the treated water rather than the scum discharge device, the inclined plate device can be efficiently installed even in shallow final sedimentation tanks without interfering with existing equipment, thereby increasing the water treatment capacity.

[0016] The solid-liquid separation system may further comprise a scraper that scrapes up sludge at the bottom of the final sedimentation tank and suspended solids on the water surface of the final sedimentation tank. In a side view, the plurality of inclined plates may be arranged inside the sludge scraper.

[0017] This allows the plurality of inclined plates to be arranged in the final sedimentation tank without interfering with the sludge scraper. Furthermore, by arranging the plurality of inclined plates inside the sludge scraper in a side view, the inclined plate device can be arranged even in a final sedimentation tank with shallow water depth, and the water treatment capacity can be enhanced. Effects of the Invention

[0018] According to the present invention, it is possible to provide a solid-liquid separation system capable of enhancing treatment capacity even in a final sedimentation tank with shallow water depth. Brief Description of the Drawings

[0019] [Figure 1] Side view of the solid-liquid separation system according to an embodiment of the present disclosure. [Figure 2] Cross-sectional view taken along line AA in Figure 1. [Figure 3A] Schematic side view showing scum trapping by a scum discharging device. [Figure 3B] Schematic side view showing scum trapping by a scum discharging device. [Figure 4] Schematic cross-sectional view taken along line BB in Figure 3B. [Figure 5] Perspective view showing a part of the inclined plate device. [Figure 6] (a) Perspective view of an inclined plate unit, (b) Front view of the inclined plate unit. [Figure 7] Side view showing an example of a support structure for an inclined plate unit to a support member. [Figure 8] Plan view of an inclined plate device according to a modified example of an embodiment of the present disclosure. Mode for Carrying Out the Invention

[0020] Hereinafter, a solid-liquid separation system according to an embodiment of the present disclosure will be described with reference to the drawings.

[0021] Fig. 1 is a side view showing the solid-liquid separation system 100 of the present embodiment. The solid-liquid separation system 100 of the present embodiment is applied to solid-liquid separation of water to be treated W in a final sedimentation basin P of a sewage treatment plant.

[0022] As shown in Fig. 1, the solid-liquid separation system 100 includes a final sedimentation basin P, an inclined plate device 1, an overflow weir 2, a water channel 3, an inflow part 4, an outflow part 5, a sludge scraper 6, a sludge hopper 7, a scum discharge device 8, a sludge interface meter 9, a notification device 10, and a controller 11.

[0023] Into the final sedimentation basin P, water to be treated having an activated sludge suspended solids concentration of at least 500g / m 3 flows in at a water area load of 8m 3 / (m 2 ·day) or more. In other words, the solid-liquid separation system 100 of the present embodiment has an MLSS concentration of at least 500g / m 3 and is configured to be capable of reducing the sludge concentration of water to be treated, which flows in at a water area load of 8m 3 / (m 2 ·day) or more, to a sludge concentration not exceeding a predetermined reference value (management target value). The management target value for the sludge concentration of the treated water in the final sedimentation basin is, for example, 10g / m 3 or less, preferably 5g / m 3 or less. Alternatively, for example, the predetermined management target value in Kariya City, Aichi Prefecture is 25g / m 3 or less based on pollution prevention agreements, and may vary depending on the region. The upper limit of the water area load of the final sedimentation basin is not limited as long as it is 8m 3 / (m 2 ·day) or more. However, the solid-liquid separation system 100 of the present embodiment is applied to, for example, a final sedimentation basin of a sewage treatment plant into which water to be treated flows at a water area load of 8m 3 / (m 2 ·day) or more and 100m 3 / (m 2 ·day) or less.

[0024] The inlet 4 is where the raw water (water to be treated W) flows into the final sedimentation tank P. The outlet 5 is located on the opposite side of the inlet 4 in the final sedimentation tank P. The outlet 5 is positioned opposite the inlet 4. The purified water to be treated W flows out of the final sedimentation tank P from the outlet 5.

[0025] The inclined plate device 1 is a horizontal flow type solid-liquid separation device. The inclined plate device 1 is located upstream (towards the inlet 4) from approximately the center of the final sedimentation tank P. The inclined plate device 1 has multiple inclined plates 41 that are parallel to the water flow direction D (direction from the inlet 4 to the outlet 5) of the water to be treated and are inclined with respect to the horizontal direction. Details of the inclined plate device 1 will be described later.

[0026] The overflow weir 2 is positioned near the water surface of the treated water W on the downstream side (outlet side 5). The overflow weir 2 is formed along the direction from upstream to downstream (water flow direction D). The waterway (trough) 3 is formed surrounded by the overflow weir 2 and is connected to the outlet 5. Note that the configuration is not limited to the overflow weir 2; a pipe with holes may also be used.

[0027] The water to be treated W, which flows from the inlet 4 into the final sedimentation tank P, moves along the water flow direction D, passes between the inclined plate devices 1, and as it passes, the sludge in the water to be treated W settles and settles on the inclined plates 41, thereby purifying the water to be treated W. The sludge that settles on the inclined plates 41 falls due to its own weight as it accumulates.

[0028] The sludge scraper 6 is located in the final sedimentation tank P. The sludge scraper 6 collects the settled sludge M near the bottom of the final sedimentation tank P. Upstream of the scum discharge device 8, the sludge scraper 6 passes near the water surface and also scrapes up suspended matter (scum). Sludge is scraped into the sludge hopper 7 by the sludge scraper 6. Sludge is discharged from the sludge hopper 7. The scum discharge device 8 is located approximately in the center of the final sedimentation tank P, at the water surface WS. The scum discharge device 8 discharges suspended matter at the water surface WS.

[0029] The sludge interface meter 9 detects the height of the sludge interface that has settled on the bottom surface PB. The notification device 10 alerts the administrator. The controller 11 controls the notification device 10 based on the measurement value of the sludge interface meter 9.

[0030] (Sludge scraping machine 6) The sludge scraper 6 is positioned from near the bottom PB of the final sedimentation tank P to the water surface WS. Figure 2 is a cross-sectional view between A and B in Figure 1.

[0031] The sludge scraper 6 has multiple sprockets 21a, 21b, 21c, and 21d, a pair of chains 22, and multiple flight plates 23.

[0032] The final sedimentation tank P is equipped with two sets of sprockets 21a, 21b, 21c, and 21d. One set is positioned near the left wall PL of the final sedimentation tank P, and the other set is positioned near the right wall PR of the final sedimentation tank P. The sprockets 21a, 21b, 21c, and 21d near the left wall PL and the sprockets 21a, 21b, 21c, and 21d near the right wall PR are positioned symmetrically in the width direction F. The width direction F is perpendicular to the water flow direction D and is horizontal.

[0033] In this specification, "horizontal direction" does not have a strict meaning, but includes errors and encompasses the range that can be recognized as "horizontal direction" according to common sense. Similarly, in this specification, "vertical direction" does not have a strict meaning, but includes errors and encompasses the range that can be recognized as "vertical direction" according to common sense. Furthermore, in this specification, "parallel" does not have a strict meaning, but includes errors and encompasses the range that can be recognized as "parallel" according to common sense.

[0034] Sprocket 21a is located near the bottom surface PB of the final sedimentation tank P, downstream of the sludge hopper 7. Sprocket 21b is located above sprocket 21a, near the water surface WS. Sprocket 21c is located approximately in the center between the inlet 4 and outlet 5, near the water surface WS. Sprocket 21d is located near the bottom surface PB, near the outlet 15.

[0035] A pair of chains 22 are wrapped around two sets of sprockets 21a, 21b, 21c, and 21d. Each chain 22 is positioned near the end of the width direction F of the final sedimentation tank P. As shown in Figure 2, the left chain 22 is positioned near the left wall PL of the final sedimentation tank P and is wrapped around the left sprockets 21a, 21b, 21c, and 21d. The right chain 22 is positioned near the right wall PR of the final sedimentation tank P and is wrapped around the right sprockets 21a, 21b, 21c, and 21d.

[0036] As shown in Figure 1, chain 22 is positioned along the bottom surface PB of the final sedimentation tank P between sprocket 21d and sprocket 21a. Chain 22 is positioned from the bottom surface PB towards the water surface WS between sprocket 21a and sprocket 21b. Chain 22 is positioned along the water surface WS between sprocket 21b and sprocket 21c. Chain 22 is positioned from the water surface WS towards the bottom surface PB between sprocket 21c and sprocket 21d. Chain 22 is positioned from sprocket 21c towards the bottom surface PB of the final sedimentation tank P so as not to interfere with the overflow weir 2. Chain 22 sinks towards the bottom surface PB upstream of the scum discharge device 8 between sprocket 21c and sprocket 21d. The chain 22 is supported from below by a support base 24 between sprocket 21b and sprocket 21c, and by a support base 25 between sprocket 21c and sprocket 21d.

[0037] Multiple flight plates 23 are fixed to the left chain 22 and the right chain 22. Each flight plate 23 is positioned along the width direction F of the final sedimentation tank P, as shown in Figure 2. The flight plates 23 are positioned outside the chain 22. The flight plates 23 rotate together with the chain 22 as the sprockets 21a, 21b, 21c, and 21d rotate. Settlement sludge M accumulates near the bottom of the final sedimentation tank P. The accumulated sludge M is collected by the flight plates 23 in the sludge hopper 7 as the sludge scraper 6 rotates clockwise in Figure 1, and then discharged. The sludge scraper 6 passes near the water surface WS and scrapes up suspended matter (scum).

[0038] (Scum discharge device 8) The scum discharge device 8 is located near the water surface WS and downstream of the sprocket 21c. The scum discharge device 8 is located downstream (outlet side 5) of the portion of the sludge scraper 6 that passes near the water surface. The scum discharge device 8 is located on the water surface of the treated water W and captures scum on the water surface and discharges it outside the final sedimentation tank P.

[0039] Figures 3A and 3B are schematic side views illustrating the capture of scum by the scum discharge device 8. Figure 4 is a schematic cross-sectional view taken along the arrow between B and C in Figure 3B.

[0040] The scum discharge device 8 comprises a scum pipe 31 and a rotating mechanism 32. The scum pipe 31 is stretched between the left wall PL and the right wall PR (see Figure 4) of the final sedimentation tank P. The scum pipe 31 is positioned so that its longitudinal direction aligns with the width direction F.

[0041] The scum pipe 31 has an intake opening 31a along its longitudinal direction. The scum pipe 31 is configured to rotate around its center axis between a normal position p1 (see Figure 3A) where the intake opening 31a faces upward in the vertical direction G, and an intake position p2 (see Figure 3B) where the intake opening 31a faces the inlet 4 side (upstream side). The scum pipe 31 of the scum discharge device 8 is positioned so that the water surface WS passes through the intake opening 31a at the intake position p2.

[0042] The rotating mechanism 32 rotates the scum tube 31. The rotating mechanism 32 includes, for example, a cylinder 32a driven by hydraulics or pneumatics. The cylinder 32a of the rotating mechanism 32 is fixed to the left wall PL or the right wall PR of the final sedimentation tank P. The cylinder 32a of the rotating mechanism 32 is rotatably connected to a lever 33 fixed to the rotation axis of the scum tube 31. When the cylinder 32a of the rotating mechanism 32 extends, the lever 33 is pushed toward the inlet 4, and the scum tube 31 rotates from the normal position p1 to the swallowing position p2. When the cylinder 32a of the rotating mechanism 32 retracts, the lever 33 is pushed toward the outlet 15, and the scum tube 31 rotates from the swallowing position p2 back to the normal position p1.

[0043] As shown in Figure 3B, with the scum tube 31 positioned at the intake position p2, scum (dead leaves, debris, foam, etc.) S enters the inside of the scum tube 31 through the intake opening 31a and is captured along the water flow from the inlet 4 to the outlet 5. Once the scum S is captured, the rotating mechanism 32 rotates the scum tube 31 to its normal position p1 (see Figure 3B), and the intake opening 31a is directed upward. This traps the scum S inside the scum tube 31. As shown in Figure 4, the scum S trapped in the scum tube 31 flows along the longitudinal direction (width direction F) of the scum tube 31 towards the side wall of the final sedimentation tank P and is discharged outside the final sedimentation tank P.

[0044] The scum S captured by the scum discharge device 8 is discharged outside the final sedimentation tank P, then returned to the grit tank or inflow main line (inlet of the sewage treatment plant), where it is removed while circulating within the water treatment facility, or it is separated into solid and liquid by a scum separator or dewatering machine.

[0045] (Slanted plate device 1) As shown in Figures 1 and 2, the inclined plate device 1 is supported by a plurality of support members 35. Each support member 35 is arranged along the width direction F and fixed to the left wall PL and right wall PR of the final sedimentation tank P. The plurality of support members 35 are arranged in line in the water flow direction D. The inclined plate device 1 is fixed to the support members 35 using fastening members such as bolts, or by being sandwiched by anti-slip fittings made of steel or the like (see Figure 7, described later).

[0046] As shown in Figure 1, the inclined plate device 1 is positioned inside the sludge scraper 6 in a side view. The inclined plate device 1 is positioned inside the chain 22 of the sludge scraper 6 in a side view. The inclined plate device 1 is positioned upstream of the scum discharge device 8 in the water flow direction D. The inclined plate device 1 is positioned at a predetermined distance from the bottom surface PB.

[0047] The inclined plate device 1 has a plurality of inclined plate units 40. Figure 5 is a perspective view showing a part of the inclined plate device 1. In this embodiment, the inclined plate device 1 has five inclined plate units 40 arranged in the width direction F as shown in Figure 2, twelve inclined plate units 40 arranged in the water flow direction D as shown in Figure 1, and two inclined plate units 40 arranged in the vertical direction G. In the inclined plate device 1 of Figure 5, only two inclined plate units 40 are shown in the water flow direction D.

[0048] Figure 6(a) is a perspective view showing one inclined plate unit 40. The inclined plate unit 40 shown in Figure 6(a) is the lower inclined plate unit 40 of the inclined plate device 1 shown in Figure 5. Figure 6(b) is a front view of the inclined plate unit 40 shown in Figure 6(a).

[0049] The inclined plate unit 40 has a plurality of inclined plates 41 and a support frame 42. The plurality of inclined plates 41 are arranged parallel to each other. The support frame 42 supports the plurality of inclined plates 41. The support frame 42 forms a rectangular parallelepiped.

[0050] The inclined plate 41 is a rectangular plate-like member, and its main surfaces (surfaces 41a and 41b shown in Figure 6(b)) are arranged parallel to the water flow direction D. The inclined plate 41 is supported by the support frame 42 at an inclination such that the position of the upper end 41i in the vertical direction G is located on either side of the width direction F relative to the position of the lower end 41j. The main surface 41a is the surface facing upward of the inclined plate 41, and the main surface 41b is the surface facing downward of the inclined plate 41.

[0051] In the inclined plate unit 40 shown in Figure 6(a), each of the inclined plates 41 is inclined such that its upper end 41i is located on the left wall PL side than its lower end 41j. Regarding the inclined plate 41, as shown in Figure 6(b), the angle between the inclined plate 41 and the width direction F, viewed along the direction of arrow D, is denoted as θa, and the angle between the inclined plate 41 and the vertical direction G is denoted as θb. In this case, the angle θa is preferably between 20 degrees and 80 degrees, and particularly preferably 60 degrees. The angle θb is preferably set between 10 degrees and 70 degrees, and particularly preferably 30 degrees.

[0052] In the inclined plate unit 40, the multiple inclined plates 41 are arranged with a predetermined distance between them and adjacent inclined plates 41. The distance L between adjacent inclined plates 41 is shown as the distance along the width direction F, as shown in Figure 6(b).

[0053] Furthermore, the inclined plate 41 is formed from a generally rectangular member. The material of the inclined plate 41 is preferably PVC (polyvinyl chloride), particularly rigid polyvinyl chloride, but is not limited to this. The material of the inclined plate may be, for example, a thermoplastic resin, such as a vinyl resin such as polyvinyl chloride, a carbonate resin such as polycarbonate, an ester resin such as polyethylene terephthalate, an acrylic resin such as polymethyl methacrylate, an olefin resin such as polypropylene or polyethylene, a styrene resin such as ABS, or a copolymer or mixed resin thereof, or a thermosetting resin such as epoxy resin or unsaturated polyester resin, or it may be metal, ceramic, wood, rubber, etc.

[0054] The inclined plate 41 can be manufactured by deformed extrusion molding, injection molding, etc., but it is preferable to manufacture it by extruding a flat plate and then forming reinforcing ribs etc. by vacuum forming, or by applying sludge capture treatment to the back surface of the inclined plate by deformed extrusion molding.

[0055] The support frame 42 supports the multiple inclined plates 20 in the inclined state as described above. As shown in Figure 6(a), the support frame 42 has a plurality of widthwise frame members 43, a plurality of vertical frame members 44, and a plurality of water flow direction frame members 45. The widthwise frame members 43 are arranged along the width direction F. The vertical frame members 44 are arranged along the vertical direction G. The water flow direction frame members 45 are arranged along the water flow direction D. The widthwise frame members 43, the vertical frame members 44, and the water flow direction frame members 45 are arranged to surround the plurality of inclined plates 20 as described above. The plurality of widthwise frame members 43, the plurality of vertical frame members 44, and the plurality of water flow direction frame members 45 form the edge portions of the rectangular parallelepiped inclined plate unit 40.

[0056] As shown in Figure 5, in the inclined plate device 1, multiple inclined plate units 40, as shown in Figure 6(a), are arranged in a row in the width direction F, the water flow direction D, and the vertical direction G. As described above, the inclined plate units 40 in the lower row are inclined such that the upper end 41i is located on the left wall PL side than the lower end 41j (see Figure 2). The inclination direction of the inclined plates 41 in all of the inclined plate units 40 in the lower row is the same, with the upper end 41i located on the left wall PL side than the lower end 41j. That is, the inclined plate 41 in the second row from the upstream side of the lower row shown in Figure 5 is inclined such that the upper end 20i is located on the left wall PL side than the lower end 20j, similar to the inclined plate 41 in the first row from the upstream side of the lower row. In this way, the inclined plates 20 in the same row in the vertical direction G are inclined in the same direction.

[0057] As shown in Figure 5, the inclined plate unit 40 in the upper section is inclined such that its upper end 41i is located closer to the right wall PR than its lower end 41j. In this way, the inclined plates 20 are arranged so that the inclination direction of the inclined plates 41 of adjacent sections is opposite in the vertical direction G. The inclination direction of the inclined plates 41 in all of the inclined plate units 40 in the upper section is the same, with the upper end 41i located closer to the right wall PR than its lower end 41j. That is, the inclined plate 41 in the second row from the upstream side of the upper section shown in Figure 5 is inclined such that its upper end 20i is located closer to the right wall PR than its lower end 20j, similar to the inclined plate 41 in the first row from the upstream side of the upper section. The inclined plates 41 of the upper section inclined plate unit 40 are arranged symmetrically with the inclined plates 41 of the lower section inclined plate unit 40. The upper inclined plate unit 40 has the same configuration as the lower inclined plate unit 40 (with the same dimensions and number of inclined plates), and for example, by rotating the upper inclined plate unit 40 180 degrees around its vertical axis, it can be used as the lower inclined plate unit 40.

[0058] Figure 7 is a side view showing an example of a support structure for the inclined plate unit 40 to the support member 35. As shown in Figure 7, the inclined plate unit 40 is prevented from shifting position by a slip prevention fitting 51 made of steel or the like. The slip prevention fitting 51 is L-shaped in side view. The slip prevention fitting 51 is fastened to the support member 35 by bolts 52. The inclined plate unit 40 is arranged across two support members 35. The inclined plate unit 40 is sandwiched from the upstream and downstream sides in the water flow direction D by the slip prevention fittings 51 fixed to each of the two support members 35. The slip prevention fitting 51 fixed to the upstream support member 35 is positioned facing the vertical frame member 44 on the upstream side of the vertical frame member 44. The slip prevention fitting 51 fixed to the downstream support member 35 is positioned facing the vertical frame member 44 on the downstream side of the vertical frame member 44. This prevents the inclined plate unit 40 from shifting position. The anti-slip fitting 51 does not necessarily have to be fixed to the vertical frame member 44, but it may be fixed by welding, fastening, or the like.

[0059] In the inclined plate device 1 of this embodiment, multiple inclined plate units 40 are arranged in a row in the water flow direction D, the vertical direction G, and the width direction F. Adjacent inclined plate units 40 are connected to each other using fastening members such as bolts.

[0060] By modularizing the system in this way, the size of the inclined plate device 1 can be easily adjusted according to the size of the final sedimentation tank P.

[0061] (Sludge interface meter 9) The sludge interface meter 9 shown in Figures 1 and 2 measures the depth of the sludge M settled on the bottom surface PB of the final sedimentation tank P. The sludge interface meter 9 measures the depth of the sludge by emitting ultrasonic waves toward the bottom surface PB and receiving the reflected waves.

[0062] The sludge interface meter 9 is fixed to the inclined plate device 1 on its lower side. The sludge interface meter 9 is fixed to one inclined plate unit 40, but it is not limited to the inclined plate unit 40; it may also be fixed to the support member 35, or to the left wall PL or right wall PR of the final sedimentation tank P.

[0063] The sludge interface meter 9 measures the sludge depth at predetermined intervals and outputs the measured value to the controller 11.

[0064] (Notification device 10) The notification device 10 shown in Figure 1 notifies the administrator based on the sludge concentration measured by the sludge interface meter 9. The administrator can then check the site conditions, etc., upon hearing the notification information (alarm).

[0065] The notification device 10 can use a speaker, monitor, etc., and may use sound, light, vibration, etc., but the important thing is that it can notify the administrator that the height of the sludge interface has reached a predetermined threshold.

[0066] The notification device 10 can be installed at the monitoring facility if it is being monitored remotely, or it may be placed near the final sedimentation tank P.

[0067] (Controller 11) The controller 11 shown in Figure 1 has a processing unit such as a CPU (Central Processing Unit) and main memory including non-volatile memory such as ROM (Read Only Memory) and volatile memory such as RAM (Random Access Memory). The controller 11 reads the program stored in the main memory and executes predetermined processing according to the program. Memory is an example of a non-transitory computer-readable recording medium. The program may also be distributed to the controller 11 via a network.

[0068] The controller 11 stores predetermined thresholds. When the measured value received from the sludge interface meter 9 reaches the predetermined threshold, the controller 11 controls the notification device 10 to notify the administrator that the height of the sludge interface has reached the predetermined threshold.

[0069] As described above, the solid-liquid separation system 100 of this embodiment is a solid-liquid separation system arranged in the final sedimentation tank P of a sewage treatment plant, and comprises an inclined plate device 1 having a plurality of inclined plates 41 that are parallel to the water flow direction D through which the water to be treated flows and are inclined with respect to the horizontal direction.

[0070] Since the multiple inclined plates, which are arranged parallel to the water flow direction D through which the treated water flows, do not need to be placed below the overflow weir 2, they can be installed even in the shallow final sedimentation tank P, thereby increasing the water treatment capacity.

[0071] (Other embodiments) Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be modified as appropriate without departing from the spirit of the invention.

[0072] (A) In the solid-liquid separation system of the above embodiment, the spacing between adjacent inclined plates 41 is the same in all of the multiple inclined plate units 40. However, the system is not limited to this, and the spacing between adjacent inclined plates 41 in the inclined plate unit 40 located on the inflow side of the water to be treated may be wider than the spacing between adjacent inclined plates 41 in the inclined plate unit 40 located on the outflow side of the water to be treated. An example of such a configuration is shown in Figure 8. Figure 8 is a plan view of the inclined plate device 1'.

[0073] In the plan view of the inclined plate device 1' shown in Figure 8, two inclined plate units 40 are arranged side by side in the width direction F, and six inclined plate units 40 are arranged side by side in the water flow direction D. Although not shown, the inclined plate device 1' has two tiers of inclined plate units 40 arranged in the vertical direction G, and the plan view in Figure 8 shows the upper tier of inclined plate units 40.

[0074] If La is the distance between adjacent inclined plates 41 in the first and second inclined plate units 40 from the upstream end in the water flow direction D, Lb is the distance between adjacent inclined plates 41 in the third and fourth inclined plate units 40 from the upstream end in the water flow direction D, and Lc is the distance between adjacent inclined plates 41 in the fifth and sixth inclined plate units 40 from the upstream end in the water flow direction D, then La > Lb > Lc is set.

[0075] By widening the distance L between the inclined plates 41 of the inlet-side inclined plate unit 40, blockage of the inlet-side inclined plates by sludge can be suppressed even when treated water with a high concentration of suspended solids is inflow. Conversely, by narrowing the distance L between the inclined plates 41 on the outlet side, the settling area can be increased.

[0076] Furthermore, the spacing between adjacent inclined plates 41 in the inclined plate units 40 arranged in a line in the vertical direction G is the same. For example, in Figure 8, the spacing between adjacent inclined plates 41 in the inclined plate units 40 located below the first and second inclined plate units 40 from the upstream end in the water flow direction D is set to La. The inclination direction of the inclined plates 41 in the lower inclined plate unit 40 is symmetrical to the inclination direction of the inclined plates 41 in the upper inclined plate unit 40, as described in the above embodiment.

[0077] Furthermore, in Figure 8, the spacing between the inclined plates 41 decreases in three stages toward the downstream side in the water flow direction D, but it is not limited to three stages; it could be two stages or four or more stages.

[0078] (B) In the inclined plate device 1 of the solid-liquid separation system 100 of the above embodiment and inclined plate device 1' of (A) above, the inclined plate units 40 are arranged in two stages in the vertical direction G, but there may be one stage or three or more stages. In that case, the inclined plate unit 40 further arranged on top of the upper stage is inclined such that its upper end 41i is located on the left wall PL side than its lower end 41j, similar to the inclined plate unit 40 of the lowest stage.

[0079] In this way, the inclined plates 41 are arranged such that the inclination directions of adjacent plates 41 are opposite in the vertical direction G.

[0080] (C) In the inclined plate device 1 of the solid-liquid separation system 100 described above, five inclined plate units 40 are arranged in the width direction F, but the number is not limited to five, and there may be fewer than five or six or more. Also, in the inclined plate device 1 of the solid-liquid separation system 100 described above, twelve inclined plate units 40 are arranged in the water flow direction D, but the number is not limited to twelve, and there may be fewer than twelve or thirteen or more.

[0081] (D) In the solid-liquid separation system 100 of the above embodiment, the inclined plate device 1 is composed of a combination of multiple inclined plate units 40, but it is not limited to this, and it is not necessary for the inclined plate units 40 to be separated. In this case, it is preferable that the inclined plates 41 are arranged in the width direction F of the final sedimentation tank P and extend over the entire width direction F of the final sedimentation tank P. Multiple inclined plates 41 arranged in the width direction F may be arranged in multiple stages in the vertical direction G. Multiple inclined plates 41 arranged in the width direction F may be arranged in multiple rows in the water flow direction D.

[0082] (E) In the solid-liquid separation system 100 of the above embodiment, the rotating mechanism 32 that rotates the scum tube 31 has a cylinder 32a that expands and contracts by hydraulics or pneumatics, but it is not limited to this, and a solenoid or the like may be used instead of a piston that expands and contracts by hydraulics or pneumatics. Alternatively, the rotating mechanism 32 may be a mechanism in which a motor is connected to a rotating shaft provided at one end of the scum tube 31, and the scum tube 31 is rotated by the rotation of the motor. [Explanation of symbols]

[0083] 1: Inclined plate device, 1': Inclined plate device, 2: Overflow weir, 3: Waterway, 4: Inlet, 5: Outlet, 6: Sludge scraper, 7: Sludge hopper, 8: Scum discharge device, 9: Sludge interface meter, 10: Notification device, 11: Controller, 20: Inclined plate, 20i: Upper end, 20j: Lower end, 21: Sprocket, 21a: Sprocket, 21b: Sprocket, 21c: Sprocket, 21d: Sprocket, 22: Chain, 23: Flight plate, 24: Support base, 25: Support base, 31: Scum pipe, 31a: Inlet, 32: Rotating mechanism, 32a: Cylinder, 33: Lever, 35: Support member, 40: Inclined plate unit, 41: Inclined plate, 41a: Main surface, 41b: Main surface, 41i: Upper end, 41j: Lower end, 42: Support frame, 43: Width direction frame member, 44: Vertical direction frame member, 45: Water flow direction frame member, 100: Solid-liquid separation system, D: Water flow direction, F: Width direction, G: Vertical direction, M: Sludge, P: Final sedimentation tank, PB: Bottom surface, PL: Left wall, PR: Right wall, S: Scum, W: Water to be treated, WS: Water surface, p1: Normal position, p2: Intake position, θa: Angle, θb: Angle

Claims

1. A solid-liquid separation system installed in the final sedimentation tank of a sewage treatment plant, The device includes an inclined plate apparatus having multiple inclined plates arranged parallel to the direction of the water flow of the water to be treated and inclined with respect to the horizontal direction, Solid-liquid separation system.

2. The inclined plate is positioned such that its angle with respect to the horizontal direction is between 20 degrees and 80 degrees. The solid-liquid separation system according to claim 1.

3. The inclined plate device has a plurality of inclined plate units arranged in at least one of the width direction, vertical direction, and water flow direction of the final sedimentation tank, The plurality of inclined plates are arranged separately in the plurality of inclined plate units. The solid-liquid separation system according to claim 1.

4. The spacing between adjacent inclined plates in the inclined plate unit located on the inflow side of the water to be treated is wider than the spacing between adjacent inclined plates in the inclined plate unit located on the outflow side of the water to be treated. The solid-liquid separation system according to claim 3.

5. It is further equipped with a scum removal device for removing scum, The inclined plate device is positioned on the side of the scum discharge device that is inlet of the water to be treated. The solid-liquid separation system according to claim 1.

6. The system further includes a scraper for scraping up sludge from the bottom of the final sedimentation tank and suspended matter from the surface of the water in the final sedimentation tank. In a side view, the plurality of inclined plates are arranged inside the scraping machine. The solid-liquid separation system according to claim 1.

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