JP6527014B2 - Sludge dewatering and drying system - Google Patents

Description

  The present invention relates to a sludge dewatering and drying system in which sludge is dewatered and then cut and dried.

  Generally, when sludge such as sewage or industrial wastewater is dewatered with a belt press dehydrator etc, the moisture content of the sludge will be about 82 wt%, so when incinerating such dewatered sludge, for example, much incineration energy It will be necessary. Therefore, it has been practiced to further reduce the water content of the sludge by drying the dehydrated sludge using a drying system.

  For example, Patent Document 1 discloses a drying processing unit having a plurality of belt conveyors and a crusher installed between the belt conveyors to crush sludge as a sludge dryer for drying dehydrated sludge, and this drying processing unit And a dry air generator for supplying dry air to the

Patent No. 5515160 gazette

  By the way, in the structure of the said patent document 1, the sludge introduce | transduced into a sludge dryer is a thing dewatered by the conventional general dehydrator, and the moisture content is as high as about 82 wt%. For this reason, in the configuration of this patent document 1, in order to make the sludge introduced into the sludge dryer small and easy to dry, a configuration is adopted in which the sludge is pressed against the perforated plate and extruded into a string shape The apparatus structure tends to be large in size, and the running costs such as the power required for extrusion of sludge also become large. Moreover, in the configuration of Patent Document 1, in order to dry sludge having a high water content, a heater and a cooler for generating dry air to be blown into the sludge dryer are used, and running costs such as electric power are further increased. It has become.

  The present invention has been made in consideration of the above-mentioned conventional problems, and an object thereof is to provide a sludge dewatering and drying system capable of dewatering and drying sludge at low cost.

  The sludge dewatering and drying system according to the present invention comprises: a concentration device for gravity filtration and concentration while conveying the sludge to which a drug is added by a filter body, and addition of the sludge concentrated by the concentration device while conveying it between a pair of belts It is provided with a dewatering device for pressure dewatering, a cutting device for cutting the sludge dewatered by the dewatering device, and a drying device for drying the sludge cut by the cutting device while conveying it with a conveyer having an aeration structure. It features.

  According to such a configuration, the sludge sufficiently dehydrated by the concentrator and the dehydrator is finely cut by the cutter and then introduced into the dryer and dried. Therefore, the water content of the sludge introduced into the cutting device is sufficiently reduced, so that the sludge can be easily cut by, for example, a disk-like or plate-like cutter. For this reason, for example, large-scale equipment for pressing the sludge against the porous plate is unnecessary, the dewatered sludge can be made finer at low cost, and the water content of the sludge is sufficiently reduced. The shape of the later sludge is retained. Moreover, since the drying device only needs to dry the finely cut sludge in such a state where the water content is reduced, it is possible to dry the sludge to a desired water content even if it is natural drying that is transported by a conveyor. it can. Under the present circumstances, since the shape after cutting, ie, the multi-sided shape, is hold | maintained, the surface area which contacts air with a drying apparatus becomes large, and the drying efficiency improves sludge. For this reason, facilities, such as a heater for cooling sludge, a cooler, etc. become unnecessary, and it can dry dehydrated sludge at much lower cost.

  The concentration device may be configured to have a chemical injection device that adds an iron-based inorganic coagulant to the sludge transported by the filter body. Then, the dewatering rate of the sludge in the concentration device and the dewatering device in the subsequent stage can be further enhanced.

  The concentration device is provided on the downstream side of the moving mechanism, and a moving mechanism for moving sludge transported by the filter body in a direction intersecting the direction of transport by the filter body, and is transported on the upper surface of the filter body It may be configured to have a pressure roller for pressing the sludge with the filter body. As a result, it is possible to compact the agent added and move the sludge transported by the filter body in a direction different from the transport direction by the moving mechanism, and furthermore, the consolidated sludge is pressurized and dewatered by the pressure roller. As a result, the water content of the sludge before being introduced into the dehydrator can be greatly reduced.

  A plurality of the cutting devices are provided side by side at equal intervals in a direction orthogonal to the conveyance direction of the sludge, and a disc-shaped rotation for cutting the sludge along the conveyance direction by rotating in contact with the conveyed sludge. A plate which is provided to extend in a direction perpendicular to the conveying direction of the sludge, and is a plate that cuts the sludge along the direction orthogonal to the conveying direction by contacting with the conveyed sludge while moving up and down Among the upper and lower cutters, at least one of the upper and lower cutters may be included. By cutting the sludge using such a rotary cutter or upper and lower cutters, the sludge before being introduced into the drying device can be finely divided at low cost using a simple device, and the area exposed to air can be increased. it can.

  The drying device may be configured to have a cover member that covers the conveyor. Then, the sludge transported and dried by the conveyor can be protected from the outside air and humidity.

  Further, the sludge dewatering and drying system according to the present invention includes a cutting device for cutting sludge which has been added with chemicals and dewatered, and drying carried out while conveying the sludge cut by the cutting device by a conveyer having an aeration structure. And a plurality of cutting devices are provided side by side at equal intervals in a direction orthogonal to the sludge transport direction, and cut sludge along the transport direction by rotating in contact with the transported sludge. A disk-shaped rotary cutter is provided to extend in a direction perpendicular to the sludge transport direction, and contacts sludge transported up and down while moving sludge in the direction orthogonal to the transport direction. It is characterized by having at least one cutter among plate-like upper and lower cutters to be cut along.

  Such a configuration also makes it possible to dewater and dry the sludge at low cost.

  The cutting device may include the rotary cutter and the upper and lower cutters, and the upper and lower cutters may be disposed downstream of the rotary cutter. Then, after the sludge is first cut into a long strip shape along the transport direction by the rotary cutter, it can be smoothly cut by the next upper and lower cutters to be formed into a dice shape.

  According to the present invention, since the dewatered sludge can be cut, divided and dried using a cutting device having a simple structure, the sludge can be dewatered and dried at low cost.

FIG. 1 is a side view showing an overall configuration of a sludge dewatering and drying system according to an embodiment of the present invention. FIG. 2 is an enlarged plan view of an essential part of a concentration device constituting the sludge dewatering and drying system shown in FIG. FIG. 3 is a side view in the vicinity of a cutting device and a drying device provided on the downstream side of the dewatering device constituting the sludge dewatering and drying system shown in FIG. FIG. 4 is an explanatory view schematically showing a state in which the sludge is cut by the rotary cutter constituting the cutting device, FIG. 4 (A) is a plan view, and FIG. 4 (B) is a side view FIG. FIG. 5 is an explanatory view schematically showing a state in which the sludge is cut by the upper and lower cutters constituting the cutting device, FIG. 5 (A) is a plan view, and FIG. 5 (B) is a side view. FIG. FIG. 6 is an enlarged side view of an essential part showing one structural example of the ventilation structure of the conveyor of the drying apparatus. FIG. 7 is an enlarged side view of an essential part showing another example of the ventilation structure of the conveyor of the drying apparatus.

  BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the sludge dewatering and drying system according to the present invention will be described below in detail with reference to the attached drawings.

1. Description of Overall Configuration of Sludge Dewatering and Drying System FIG. 1 is a side view showing the overall configuration of a sludge dewatering and drying system 10 according to an embodiment of the present invention. 2 is an enlarged plan view of an essential part of the concentration device 12 constituting the sludge dewatering and drying system 10 shown in FIG. 1, and FIG. 3 is a downstream side of the dewatering device 13 constituting the sludge dewatering and drying system 10 shown in FIG. It is a side view in the vicinity of the cutting device 14 and the drying device 15 provided in.

  The sludge dewatering and drying system 10 according to the present embodiment gravity-filters the sludge with the concentrator 12 in the upper stage, and then pressure dewaters with the dehydrator 13 in the lower stage to generate a dewatered cake, and the dewatered cake is cut into an apparatus 14 After being finely cut, and then transported to the outside while being dried by the drying device 15. In the present embodiment, anaerobic digestion sludge of sewage is used as a processing target, but the sludge dewatering and drying system 10 according to the present embodiment is also used for sludge treatment of sludge other than sewage sludge, for example, factory wastewater or wastewater in mines. it can.

  The sludge dewatering and drying system 10 (hereinafter, also simply referred to as the “system 10”) is provided with a concentration unit 12 provided with a filtration unit 18 for gravity filtration (gravity concentration) of sludge on the upper surface 16a of the filter cloth belt 16 traveling on the orbit. The sludge concentrated by the concentrator 12 is conveyed while being held between the pair of filter cloth belts 20 and 22 and is conveyed while being dewatered under pressure and dewatered. A cutting device 14 and a drying device 15 for drying the sludge cut by the cutting device 14 while conveying it by a conveyor 23 having a ventilation structure 23 a are provided. Just before the concentration apparatus 12, a coagulation mixing tank 24 is provided for mixing the polymer flocculant F1 as a medicine in the sludge conveyed from the front stage equipment of the system 10. As the polymer coagulant F1, a generally known one may be used, and examples thereof include anionic polymer coagulant and cationic polymer coagulant.

1.1 Description of Concentration Apparatus First, the concentration apparatus 12 will be described.

  As shown in FIG. 1 and FIG. 2, the concentration device 12 filters the sludge introduced from the aggregation mixing tank 24 onto the upper surface 16 a of the filter cloth belt 16 by gravity and the sludge gravity-filtered by the filtration unit 18. And pre-dewatering rollers (pressure rollers) 25 and 26 for pressure-dewatering with the filter cloth belt 16 and discharging it to the lower-stage dewatering device 13. In the middle of the filtration unit 18, a consolidation mechanism 28 for pressing and consolidating sludge with the upper surface 16a of the filter cloth belt 16 and a direction crossing the transport direction by the filter cloth belt 16 (orthogonal in this embodiment) A moving mechanism 30 for moving the sludge is provided.

  The filtration unit 18 is configured by an upper surface (outer peripheral surface) 16 a of an endless filter cloth belt 16 which is wound around a plurality of rollers and the preliminary dewatering rollers 25 and 26 and is rotationally driven in one direction. The filtration unit 18 is a means for filtering and separating the water contained in the sludge by gravity by placing the sludge on the upper surface 16 a of the filter cloth belt 16 stretched between the predetermined rollers 19 a and 19 b.

  The filter cloth belt 16 is made of, for example, a long band-like filter cloth having water permeability, a long band-like metal screen having a plurality of fine holes formed in a mesh shape, and the like. Dewatering rollers 25 and 26 are wound around. The filter cloth belt 16 travels in the direction of the arrow shown in FIG. 1 (counterclockwise in FIG. 1) as a predetermined roller is rotationally driven by a drive source such as a motor whose drive is controlled by a control device (not shown). It is possible. Thus, in FIGS. 1 and 2, the direction from the right side (upstream side) to the left side (downstream side) is the conveyance direction of the sludge in the concentrator 12.

  Therefore, the sludge introduced to the upstream position of the filtration unit 18 from the outlet port 24 a of the coagulation mixing tank 24 is transported to the downstream side by the filter cloth belt 16, and only water permeates the filter cloth belt 16 by gravity. The filtered and dewatered filtered water (separation liquid, filtrate) is recovered by the filtrate receiver 31 (see FIG. 1).

  A rod body 32 is provided upright at a predetermined position of the upper surface 16a of the filter cloth belt 16 constituting the filtration section 18 (upstream of the most upstream consolidation mechanism 28 in FIG. 1). The rod 32 is an obstacle for contacting and dispersing the sludge transported on the filter cloth belt 16 and promoting drainage thereof, and the installation position, the number, the shape, and the like can be appropriately changed.

  On the upstream side of the moving mechanism 30 in the filtration unit 18, a chemical injection device (chemical addition device) 36 is provided which adds the inorganic coagulant F2 as a chemical to the sludge to be conveyed. The chemical feeder 36 includes a chemical tank 36a for storing the inorganic coagulant F2, and a line 36b connected to the outlet of the chemical tank 36a. As the inorganic coagulant F2, a generally known one may be used, and examples thereof include iron-based and aluminum-based ones. The line 36 b is disposed across the width direction of the filter cloth belt 16, and the inorganic flocculant F 2 can be added to the sludge from an addition nozzle (not shown). The line 36 b may be disposed so that the inorganic flocculant F 2 can be added to the sludge fed into the coagulation mixing tank 24.

  On the other hand, the above-mentioned polymer flocculant F1 is added to the sludge immediately before being introduced into the coagulation mixing tank 24 by the chemical feeder (drug adding device) 38. The chemical feeder 38 includes a chemical tank 38a for storing the polymer flocculant F1, and a line 38b connected to the outlet of the chemical tank 38a. The line 38b may be configured to add the polymer coagulant F1 to the sludge transported through the filtration unit 18 as in the line 36b.

  The coagulation mixing tank 24 into which the sludge to which the polymer flocculant F1 from the chemical feeder 38 is added is introduced is a tank 24b in which the sludge is stored, and a stirrer in which the sludge in the tank 24b is stirred using the motor 24c as a driving source. And 24 d. The sludge in which the polymer flocculant F1 is sufficiently mixed in the tank 24b by the stirring blade 24d is fed to the upper surface 16a of the filter cloth belt 16 from the outlet port 24a.

  The consolidation mechanism 28 reduces the height dimension and consolidates by crushing the sludge conveyed on the filter cloth belt 16. As shown in FIG. 1, three consolidation mechanisms 28 are provided in the middle of the filtration unit 18 and arranged at positions on the upstream side and the downstream side of the two moving mechanisms 30 respectively. The number of installation of the consolidation mechanism 28 can be changed suitably.

  As shown in FIG. 1 and FIG. 2, each pressing mechanism 28 is a pressing plate disposed parallel to the filter cloth belt 16 via a predetermined distance after being curved downward toward the downstream side in the sludge transport direction. It has 28a. The pressing plate 28a is formed of a metal plate or a rubber sheet, and is provided, for example, in the width direction of the filter cloth belt 16 (see FIG. 2). The pressing plate 28a is urged downward by its own weight and the spring member 28c disposed on the upper column 28b, and the sludge conveyed on the filter cloth belt 16 can be crushed and consolidated.

  The moving mechanism 30 is consolidated by moving the sludge conveyed on the filter cloth belt 16 in the cross direction and simultaneously reducing the size in the width direction and increasing the height of the sludge, and added by the chemical feeder 36 By sufficiently kneading the inorganic coagulant F2, the filtration efficiency of the sludge in the concentrator 12 and the dehydrator 13 can be improved, and the sludge concentration can be increased. As shown in FIG. 1, two moving mechanisms 30 are provided in the middle of the filtration unit 18, and the consolidation mechanism 28 is disposed on the upstream side and the downstream side of each. The number of installed moving mechanisms 30 can be changed as appropriate.

  As shown in FIGS. 1 and 2, each moving mechanism 30 is a screw conveyor that can open toward the entire upstream side of the upper surface 16 a of the filter cloth belt 16 and receive sludge. Each moving mechanism 30 is disposed close to the pair of screws 40a and 40b for moving the sludge in the direction orthogonal to the conveyance direction by the filter cloth belt 16, and on the downstream side of the screws 40a and 40b. A pair of guide plates 42a and 42b are disposed upright on the side. A gap between the pair of guide plates 42a and 42b (substantially the same as the gap between the screws 40a and 40b) is a passage (sludge passage 43) for discharging sludge from the moving mechanism 30 to the downstream side. .

  The screws 40a and 40b extend in a direction orthogonal to the direction of sludge transport by the filter cloth belt 16 and extend across the filter cloth belt 16 in the width direction. , And screw blades 41a and 41b provided in a spiral shape, respectively.

  The screw shaft 44 is axially supported at both ends in the width direction outer position of the filter cloth belt 16 by bearings (not shown), and for example, a flexible chain (not shown) or the like with respect to a predetermined roller around which the filter cloth belt 16 is wound. By being linked by the power transmission member, the filter cloth belt 16 can be rotated as it travels. You may provide drive sources, such as a motor which rotationally drives the screw shaft 44 independently.

  The screw blades 41a and 41b are provided on the outer peripheral surface of the screw shaft 44 at positions close to both sides in the width direction of the filter cloth belt 16, and the respective tips thereof are approximately the same as the gap between the guide plates 42a and 42b. It is facing via a gap. The direction of the spiral of each screw blade 41a, 41b is in the opposite shape (reverse direction) at the center line of the filter cloth belt 16, and the moving direction of the sludge by each screw 40a, 40b is set in the opposite direction. . Therefore, the screws 40a and 40b move the sludge from the outside toward the inside (center) in the width direction of the filter cloth belt 16, and both ends are outside at the central portion where their tips are separated via the gap. The sludge transferred from each other is pressed against each other and consolidated, and the inorganic coagulant F2 is sufficiently kneaded in the sludge.

  On the central portion of the screw shaft 44, that is, on the outer peripheral surface of the screw shaft 44 exposed between the screws 40a and 40b, sludge transported along the width direction center side of the filter cloth belt 16 and a pair of screws 40a and 40b A plurality of paddles 45 are provided to smoothly discharge the sludge consolidated at the center to the downstream side. The paddles 45 are, for example, impellers provided on the outer peripheral surface of the screw shaft 44 along the circumferential direction in pairs.

  The guide plates 42a and 42b are provided on the downstream side of the screws 40a and 40b and in the wall portion 46 standing at a position close to the screws 40a and 40b, and the lower end of the wall portion 46 in the sludge conveyance direction by the filter cloth belt 16. It has a bottom 47 that covers the lower half of the screws 40a and 40b by curving and projecting to the upstream side. A pair of passage plates 48a and 48b extending downstream along the sludge conveyance direction by the filter cloth belt 16 are provided at the central end of each of the guide plates 42a and 42b. The gaps between the guide plates 42a and 42b are located forward in the moving direction of the sludge by the screws 40a and 40b, and the gaps form a sludge passage 43 for discharging the sludge to the downstream side. There is.

  The wall portion 46 is a plate-like member which is set to the same height as the heights of the screws 40a and 40b, and the height can be appropriately changed. The bottom portion 47 is a plate-like member protruding from the lower end of the wall portion 46 toward the upstream side in the transport direction to a position substantially centered on the screws 40a and 40b as shown in FIG. It can be changed as appropriate. For the wall 46 and the bottom 47 constituting the guide plates 42a and 42b, a screen or the like in which a large number of fine holes are formed may be used.

  The passage plates 48a and 48b are erected so as to face each other with a gap having the same width as the gap formed between the screw blades 41a and 41b and between the guide plates 42a and 42b. The passage plates 48a and 48b are wall members that form a passage for smoothly discharging the sludge, which has been compacted in the vicinity of the center of the filter cloth belt 16 by the screws 40a and 40b, to the downstream side. It is set to the height of the degree.

  Therefore, by providing the moving mechanism 30, the sludge is sufficiently kneaded with the inorganic coagulant F2, and its height is increased by consolidation. Further, by providing the consolidation mechanism 28 before and after the movement mechanism 30, the sludge introduced into the movement mechanism 30 can be leveled and configured in a flat plate shape, and the consolidation effect by the movement mechanism 30 is enhanced. Moreover, the sludge collected in the center by the screws 40a and 40b can be flattened into a flat plate shape by the consolidation mechanism 28, so that the dewatering efficiency of the preliminary dewatering rollers 25 and 26 in the latter stage can be improved. .

  As shown in FIG. 1, the preliminary dewatering rollers 25 and 26 constitute a front dewatering portion (primary dewatering portion) of the dewatering device 13 disposed below the concentration device 12, and the filter cloth belt 16 is provided. The outer peripheral surface is press-contacted and arranged.

  The sludge that has been filtered and concentrated by the filtration unit 18 and the inorganic coagulant F 2 sufficiently kneaded by the consolidation mechanism 28 and the moving mechanism 30 is pressure-dewatered between the preliminary dewatering rollers 25 and 26 and the filter cloth belt 16 Thereafter, it is introduced into the dewatering device 13 of the next step. The preliminary dewatering rollers 25 and 26 smash the sludge compacted by the compacting mechanism 28 and the moving mechanism 30 and feed it to the dewatering device 13 in a state of being expanded in the width direction of the filter cloth belt 16 to be fed to the dewatering device 13 It also has the function of expanding the dewatering area of the sludge to improve the dewatering efficiency here.

1.2 Description of Dehydration Device Next, the dehydration device 13 will be described.

  As shown in FIG. 1, the dehydrating unit 13 dewaters the dewatering unit 50 that pressurizes and dewaters the sludge which is dropped from the outlet of the concentrator 12 and is fed while being fed between the pair of filter cloth belts 20 and 22. And 50 a pressing unit 52 for further pressing and pressing the dewatered sludge. The dehydrating apparatus 13 has substantially the same configuration as a general belt press type dehydrator.

  The filter cloth belts 20 and 22 are made of, for example, a long band-like filter cloth having water permeability, a long band-like metal screen in which a plurality of fine holes are formed in a mesh shape, or the like. The lower filter cloth belt 20 is wound around a plurality of rollers with sufficient tension, and a predetermined roller is rotationally driven by a drive source such as a motor controlled by a control device (not shown). It can travel in the direction of the arrow shown in 1 (clockwise in FIG. 1). The upper filter cloth belt 22 is also wound around a plurality of rollers with sufficient tension, and a predetermined roller is rotationally driven by a drive source such as a motor controlled by a control device (not shown). It can travel in the direction of the arrow shown in 1 (counterclockwise in FIG. 1).

  The dewatering portion 50 is a portion where the outer circumferential surfaces of the lower filter cloth belt 20 and the upper filter cloth belt 22 between the rollers 21a to 21c meander in the vertical direction while in contact or in proximity to each other. The sludge is fully pressurized and dewatered.

  A portion where the outer peripheral surfaces of the lower filter cloth belt 20 and the upper filter cloth belt 22 are in contact with or close to each other between the rollers 21 b and 21 c constitutes a pressing portion 52. The inner peripheral surfaces of the rollers 21b and 21c of the lower filter cloth belt 20 constituting the squeezing unit 52 are supported by the endless squeezing squeeze belt 53, and the sludge is further pressurized and squeezed at this portion, It is discharged to the outside as a dewatered cake with a desired moisture content.

  In the vicinity of the inlet of the dewatering device 13, the height of the sludge dropped and introduced onto the filter cloth belt 20 from the outlet of the concentration device 12 is made uniform to some extent, and the dewatering portion formed between the filter cloth belts 20 and 22 A leveling plate 51 is provided for smooth introduction to the 50 inlets 50a. The leveling plate 51 is a plate member disposed on the slightly downstream side of the falling position of the sludge from the concentrator 12 onto the filter cloth belt 20, and is a plate member gradually inclined downward toward the inlet 50a to press the sludge downward. It may be formed of a leaf spring member biased in a direction.

  At the outlet of the dehydrating apparatus 13, a delivery tray 54 is installed in an inclined posture with a trailing end falling so as to approach the filter cloth belt 20 traveling on the outer peripheral surface of the roller 21 c. The dewatered cake is scraped from the filter cloth belt 20 by the leading end of the carry-out tray 54, slips on the carry-out tray 54, and is transported and discharged.

  Therefore, in the dehydrating apparatus 13, the sludge introduced from the concentrator 12 onto the filter cloth belt 20 is drawn between the filter cloth belts 20 and 22 constituting the dewatering unit 50 from the inlet 50 a, and is held in a pressurized state At the downstream side. During this time, only water is permeated through the filter cloth belt 20 by the pressure from the filter cloth belts 20, 22 and filtered and dewatered, and further squeezed by the pressing unit 52, and then discharged onto the carry-out tray 54 as a dehydrated cake. The water filtered by the dewatering unit 50 and the pressing unit 52 passes through the filter cloth belt 20 and falls, and is collected by the filtrate receiving plate 58.

1.3 Description of Cutting Device Next, the cutting device 14 will be described.

  FIG. 4 is an explanatory view schematically showing a state in which the sludge is cut by the rotary cutter 60 constituting the cutting device 14. FIG. 4 (A) is a plan view, and FIG. 4 (B) is , A side view. Moreover, FIG. 5 is explanatory drawing which showed typically the state which is cutting the sludge by the up-and-down cutter 62 which comprises the cutting device 14, FIG. 5 (A) is a top view, FIG. ) Is a side view.

  The cutting device 14 is a device for cutting the sludge dewatered by the dehydrating device 13 and transported on the carry-out tray 54. As shown in FIG. 1, the cutting device 14 is a disk-shaped rotary cutter 60 for cutting the sludge coming out of the dewatering device 13, and the sludge cut by the rotary cutter 60 disposed on the downstream side of the rotary cutter 60. It further includes a plate-like upper and lower cutter 62 for cutting and refining.

  First, as shown in FIGS. 4 (A) and 4 (B), the rotary cutters 60 are plural (in parallel) at equal intervals in the direction orthogonal to the sludge conveyance direction (right direction in FIG. In the embodiment, for example, four disk-like thin plate members provided side by side are provided. Each rotary cutter 60 can be integrally rotated by a rotary shaft 64 connecting the centers thereof, and the lowermost portion of the outer peripheral blade surface of each rotary cutter 60 is between the upper surface of the discharge tray 54 It is arranged with a slight gap. The number of installed rotary cutters 60 can be changed as appropriate, and each rotary cutter 60 may be installed separately and freely. Further, the rotary shaft 64 of the rotary cutter 60 may be rotationally driven by a drive source such as a motor (not shown).

  Therefore, when the sludge S conveyed in the form of a wide flat plate extending over the discharge tray 54 in the width direction comes into contact with the rotary cutters 60, the rotary cutters 60 cut the sludge S along the transport direction while rotating. . As a result, the sludge S is cut and divided into a plurality (five in the present embodiment) in the direction orthogonal to the transport direction, and becomes a long narrow rod-like sludge S1.

  Next, as shown in FIGS. 5A and 5B, the upper and lower cutters 62 extend in a direction orthogonal to the sludge transport direction (right direction in FIG. 5) in the discharge tray 54. It is a rectangular thin plate member provided. The upper and lower cutters 62 can be moved up and down by a raising and lowering drive unit 66 having a drive source such as a motor (not shown), and the lower end blade surface is slightly between the upper surface and the discharge tray 54 at the lowermost position. The bottom end blade surface is disposed at a position above the sludge (here, the sludge S1) to be conveyed at the position where the clearance is moved up to the highest position. The timing of the vertical movement of the vertical cutter 62 by the vertical driving unit 66 can be changed as appropriate.

  Therefore, the sludge S1 cut and divided into narrow bars by being transported on the discharge tray 54 and cut by the rotary cutter 60 is orthogonal to the transport direction by the upper and lower cutters 62 moved up and down at a predetermined timing. It is cut and divided into pieces of sludge S2.

  The cutting device 14 may be configured to have only one of the rotary cutter 60 and the upper and lower cutters 62 depending on the specification of the drying device 15 described later, the target moisture content of sludge in the drying device 15, and the like. Moreover, the arrangement | sequence order in the case of installing both the rotary cutter 60 and the up-and-down cutter 62 is good also as making the up-and-down cutter 62 into an upstream, reverse to this embodiment. However, when the sludge S is cut by the upper and lower cutters 62 earlier than the rotary cutter 60, the sludge S1 in FIG. 4 has a shape that is long in the width direction of the carry-out tray 54 and short in the transport direction. Since the shape is such that it is rotated 90 degrees, the cut sludge tends to fall on the carry-out tray 54, making it difficult to cut and divide with the rotary cutter 60 on the downstream side. In this respect, in the configuration of the present embodiment, since the sludge S is first made into the long sludge S1 along the transport direction by the rotary cutter 60, problems such as falling are unlikely to occur, and the sludge S1 smoothly by the next upper and lower cutter 62. Can be cut to form a dice-like sludge S2.

1.4 Description of Drying Device Next, the drying device 15 will be described.

  The drying device 15 is a device for drying the sludge (sludge S2) cut by the cutting device 14 and diced into small pieces and further reducing the moisture content thereof. As shown in FIG. 3, the drying device 15 receives the sludge cut by the cutting device 14 and discharged from the carry-out tray 54, and conveys the conveyor 23 for conveying to the next process (for example, an external incineration facility) And a cover member 68 in the form of a duct.

  The conveyor 23 is a belt conveyor which is wound around a plurality of rollers and travels circularly, and has a ventilation structure 23a for drying the sludge S2 while conveying it. In the case of the present embodiment, as shown in FIG. 6, the conveyor 23 is configured by the mesh belt 70 to construct the ventilation structure 23a, and air is also circulated to the lower surface side of the sludge S2 to be transported. It has become possible to dry it well. The mesh shape of the belt 70 is configured to be smaller than the outline of the sludge S2 finely cut by the cutting device 14, so that the fall of the sludge S2 can be prevented.

  The ventilation structure 23a may be configured other than the mesh-shaped belt 70, and it is essential that the air circulates on the lower surface side of the sludge S2 to be transported, and the sludge S2 can be sufficiently dried. Therefore, for example, as shown in FIG. 7, the ventilation structure 23a may have a configuration in which the uneven structure 72a is formed on the outer peripheral surface of the mesh 72 or the non-mesh belt 72. By providing such a concavo-convex structure 72a, the air is circulated on the lower surface side of the sludge S2 to be transported, so the sludge S2 can be sufficiently dried. With regard to the concavo-convex structure 72 a of the belt 72 as well, the configuration in which at least the recess is smaller than the outer shape of the sludge S 2 finely cut by the cutting device 14 can prevent the sludge S 2 from fitting in the recess.

  The cover member 68 is a metal duct or the like provided so as to cover substantially the entire length of the conveyor 23 and is for protecting the sludge transported and dried by the conveyor 23 from the open air and humidity. The cover member 68 is provided with an air outlet 68a on the downstream side and an air outlet 68b on the upstream side. Thereby, the air is sent from the air blowing port 68a into the cover member 68 and exhausted from the exhaust port 68b, whereby the inside of the cover member 68 is ventilated, and the sludge conveyed by the conveyor 23 is dried more quickly and surely. Is possible. The cover member 68 may be omitted, for example, when the drying device 15 is installed in a dry low-humidity environment.

  In the cover member 68, dry air generated by dry air generation means (not shown) may be fed from the air outlet 68a. However, in the system 10 according to the present embodiment, the water content of the sludge is sufficiently reduced by the concentrator 12 and the dehydrator 13 in the former stage as compared with the conventional belt press type dehydrator etc. The sludge is introduced into the drying device 15 in a state, so that the sludge can be sufficiently dried without specially using dry air or the like. For this reason, the dry air generating means is basically unnecessary. In the system 10, since the moisture content of the sludge introduced to the drying device 15 is low as described above, a heater for heating the dry air is not necessary even when, for example, dry air generating means is used. Sufficient performance can be achieved only with dehumidification.

2. Next, the operation and effects of the sludge dewatering and drying system 10 configured as described above will be described.

  First, sludge, which is a processing target to be concentrated and dewatered by the system 10, is introduced into the aggregation and mixing tank 24 in a state where a predetermined polymer coagulant F1 is added by the chemical feeder 38, stirred and mixed, and flocking. It is introduced into the inlet of the concentrator 12 in the state of

  The sludge introduced into the concentration device 12 is conveyed by the filter cloth belt 16 which travels, the filtration section 18 is conveyed, and while receiving consolidation by the consolidation mechanism 28 and the movement mechanism 30, a predetermined inorganic coagulant F2 drops from the chemical feeder 36 Gravity is concentrated while being done.

  That is, the sludge to which the inorganic flocculant F2 is continuously added in a strip shape in the transport direction is crushed and drained by the consolidation mechanism 28, and then introduced into the moving mechanism 30 and caught in the rotation of the screws 40a and 40b. And while being guided by the guide plates 42a and 42b, it moves while being pushed toward the central portion. Then, the sludges are crushed and consolidated at the central portion of the filter cloth belt 16 by the pushing force of the screws 40a and 40b. Thereby, the sludge is discharged from the passage plates 48a and 48b to the downstream side through the sludge passage 43 in a state in which the dimension in the width direction is reduced and the height (bulk) is increased. Gravity filtration by the belt 16 is continued to concentrate to a desired concentration concentration. As a result, the concentration concentration of sludge in the concentrator 12 is significantly increased as compared to the case where only ordinary gravity filtration is performed in a general concentrator.

  The sludge compacted by the two moving mechanisms 30 is further transported to the downstream side and sequentially introduced to the preliminary dewatering rollers 25 and 26 while further receiving the crushing action and the drainage action by the downstream side consolidation mechanism 28. . As a result, the sludge that has been spread flat and is further concentrated is then dropped and introduced into the inlet side of the dehydrating device 13.

  The sludge introduced into the dewatering device 13 is sandwiched and pressed between a pair of upper and lower filter cloth belts 20 and 22 meandering in the dewatering unit 50, is conveyed while being efficiently dewatered, and then introduced to the pressing unit 52 Thus, it is squeezed into a dewatered cake having a desired moisture content and discharged to the discharge tray 54. For example, the moisture content of the dehydrated sludge after passing through the concentrator 12 and the dehydrator 13 of the system 10 is up to 75 wt% or less, compared to the moisture content of the dehydrated sludge in the conventional belt press type dehydrator is about 82 wt%. The decrease was obtained by experiment.

  Next, the sludge fed from the dehydrating apparatus 13 to the carry-out tray 54 and conveyed is cut and divided by the cutting apparatus 14 into fine pieces, and is introduced into the conveyor 23 of the drying apparatus 15 as the sludge S2 finely divided, for example. Be done. In the said system 10, since the cutting device 14 is comprised with the rotary cutter 60 and the up-and-down cutter 62, sludge can be divided | segmented into the dice-like fine external shape smoothly and reliably.

  Then, in the drying device 15, the sludge is further dried by conveying the sludge S2 which has been diced into fine pieces by the conveyor 23 having the aeration structure 23a, and the sludge is lowered to a desired moisture content. For example, it was confirmed that the moisture content of the sludge fed to the drying device 15 is reduced to about 55 wt% at about 75 wt% by naturally drying the die-shaped sludge S2 by the conveyor 23. In the case where the cutting device 14 was not used under the same conditions, the water content of the sludge fed into the drying device 15 was reduced to only about 65 wt% at about 75 wt%.

  In this case, the sludge dewatering and drying system 10 according to the present embodiment performs gravity filtration while conveying the sludge to which the polymer coagulant F1 and the iron-based inorganic coagulant F2 have been added as medicines by the filter cloth belt 16 which is a filter body. And the dewatering device 13 for pressurizing and dewatering while conveying the sludge concentrated by the thickening device 12 between the pair of filter cloth belts 20 and 22 and cutting the sludge dewatered by the dewatering device 13 A cutting device 14 and a drying device 15 for drying the sludge cut by the cutting device 14 while conveying it by a conveyor 23 having a ventilation structure 23 a are provided.

  Thus, in the system 10, the sludge sufficiently dehydrated by the concentrator 12 and the dehydrator 13 is finely cut by the cutter 14 and then introduced into the dryer 15 for drying. Therefore, since the moisture content of the sludge introduced into the cutting device 14 is sufficiently reduced, the sludge becomes crispy, and can be easily cut by, for example, the rotary cutter 60 or the upper and lower cutters 62. For this reason, it is unnecessary to use a large equipment such as pressing the sludge against the perforated plate as in the configuration of the above-mentioned Patent Document 1, and the dewatered sludge is finely divided by the cutting device 14 which can be configured simply and at low cost. Since the water content of the sludge is sufficiently reduced, the shape of the sludge after cutting is maintained. Moreover, since the drying device 15 only needs to dry the finely cut sludge in a state in which the water content is reduced as described above, the sludge is dried to a desired water content even if it is natural drying only transported by the conveyor 23 It can be done. Under the present circumstances, since the shape after cutting, ie, the multi-sided shape, is hold | maintained, the surface area which touches air with the drying apparatus 15 becomes large, and the drying efficiency improves sludge. For this reason, facilities, such as a heater and a cooler for drying sludge like the structure of the said patent document 1, become unnecessary, and it is possible to dry dewatered sludge at much lower cost.

  On the other hand, in the prior art such as Patent Document 1 described above, the water content of the dehydrated sludge may exceed 80 wt%, and the shape after cutting can not be maintained, and the cut sludge is the original sludge. As a result, the area exposed to the air in the drying device does not increase, and the drying is not promoted. In addition, the same applies to the case of dewatering sludge with a centrifugal dewatering machine, since the sludge is basically sand granular and can not be cut, and is in close contact with each other, so the area exposed to air is small. As a result, drying is not promoted.

  On the other hand, in the system 10, by using the concentrator 12 and the dehydrating device 13, the water content of the sludge immediately before being introduced into the cutting device 14 has a value much lower than that of the conventional general dehydrator, for example By setting the sewage sludge to about 75 wt% or less, smooth cutting of the sludge by the cutting device 14 and sufficient drying by the drying device 15 are possible. That is, in the said system 10, since the moisture content of the sludge thrown into the cutting device 14 can fully be lowered, even if it cuts with the cutting device 14 using the rotary cutter 60 or the up-and-down cutter 62, for example, the shape of sludge is It remains unbroken. As a result, in the drying device 15 using the conveyor 23 having the ventilation structure 23a, it is possible to secure a large surface area of the sludge against the wind, and it is possible to dry the sludge with high drying efficiency.

  In the above, both the polymer flocculant F1 and the iron-based inorganic flocculant F2 are illustrated as agents to be added to the sludge by the concentrator 12, but depending on, for example, the nature and type of the sludge to be dehydrated and dried by the system 10. It is not necessary to add both. However, in the experiment using the system 10, in the treatment of the anaerobic digestion sludge, the water content is lower in the case of using only the iron-based inorganic coagulant F2 than in the case of using only the polymer coagulant F1. It is preferable to use at least an iron-based inorganic flocculant F2.

  In the said system 10, the cutting device 14 can be comprised with the rotary cutter 60 and the up-and-down cutter 62, and sludge S can be formed in dice-like sludge S2. For this reason, such dice-like sludges S2 have sufficient gaps even when they are stacked on one another at the time of conveyance by the conveyor 23, and the air permeability can be sufficiently ensured.

  Further, the sludge dewatering and drying system 10 according to the present embodiment is cut by the cutting device 14 that cuts the dewatered sludge by adding the polymer coagulant F1 and the iron-based inorganic coagulant F2 as a drug, and the cutting device 14 A plurality of cutting devices 14 are provided side by side at equal intervals in the direction orthogonal to the sludge transport direction, and transported. Disk-shaped rotary cutter 60 for cutting the sludge along the conveying direction by rotating in contact with the sludge, and the sludge that is provided to extend in a direction orthogonal to the conveying direction of the sludge and is conveyed It has at least one cutter among the plate-shaped upper and lower cutters 62 which cut sludge along the direction orthogonal to the transport direction by contacting while moving up and down.

  That is, for example, even when dewatering equipment other than the above-described concentrator 12 and dehydrator 13 is used, if the sludge is sufficiently dewatered, the cutting device 14 configured by the rotary cutter 60 or the upper and lower cutters 62 is used. Thus, the sludge can be finely cut and sufficiently dried by the drying device 15, so that the sludge can be dried at low cost.

  In addition, this invention is not limited to above-described embodiment, Of course, it can change freely in the range which does not deviate from the main point of this invention.

  For example, although the configuration in which the cutting device 14 and the drying device 15 are continuously installed at the latter stage of the dehydrating device 13 is illustrated in the above embodiment, the cutting device 14 and the drying device 15 are separately installed at a position away from the dehydrating device 13 It is also good.

DESCRIPTION OF SYMBOLS 10 Sludge dewatering-and-drying system 12 Condensing device 13 Dehydrating device 14 Cutting device 15 Drying device 16, 20, 22 Filter cloth belt 18 Filtration part 23 Conveyor 23a Aeration structure 24 Coagulation mixing tank 25, 26 Pre-dewatering roller 28 Consolidation mechanism 30 Movement mechanism 36 , 38 Chemical feeder 40a, 40b Screws 42a, 42b Guide plate 50 Dewatering part 52 Pressed part 54 Ejecting tray 60 Rotary cutter 62 Upper and lower cutter 68 Cover member 70, 72 Belt 72a Concave-convex structure F1 Polymer coagulant F2 Inorganic coagulant S, S1, S2 sludge

Claims (4)

A concentrator that concentrates and concentrates chemical-added sludge while carrying it through a filter body,
A dewatering device for pressurizing and dewatering the sludge concentrated by the concentration device while conveying it between a pair of belts;
A cutting device for cutting sludge dewatered by the dewatering device;
A drying device for naturally drying the sludge cut by the cutting device while conveying it by a conveyer having an aeration structure;
Equipped with
The concentration device has a chemical injection device for adding a polymer coagulant and an iron-based inorganic coagulant to the sludge,
In the drying device, the conveyor is inclined upward in the vertical direction from the upstream side to the downstream side in the conveyance direction of the sludge, and a cover member that covers the conveyor, and the upstream of the cover member in the conveyance direction Having an air outlet provided on the side to supply air for natural drying, and an outlet provided on the downstream side of the cover member in the transport direction and discharging the air from the air outlet Features sludge dewatering and drying system. In the sludge dewatering and drying system according to claim 1,
The concentrator includes a moving mechanism that moves sludge transported by the filter in a direction intersecting the transport direction of the filter;
A sludge dewatering and drying system comprising: a pressure roller provided on the downstream side of the moving mechanism and pressurizing sludge transported on the upper surface of the filter with the filter. In the sludge dewatering and drying system according to claim 1 or 2,
A plurality of the cutting devices are provided side by side at equal intervals in a direction orthogonal to the conveyance direction of the sludge, and a disc-shaped rotation for cutting the sludge along the conveyance direction by rotating in contact with the conveyed sludge. With the cutter
It is provided to extend in a direction orthogonal to the conveyance direction of sludge, and comes in contact with the conveyed sludge while moving up and down, thereby cutting the sludge up and down along the direction orthogonal to the conveyance direction. A sludge dewatering and drying system comprising a cutter and at least one of the cutters. In the sludge dewatering and drying system according to claim 3,
The sludge dewatering and drying system is characterized in that the cutting device includes the rotary cutter and the upper and lower cutters, and the upper and lower cutters are disposed downstream of the rotary cutter.

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