Sludge treatment system and process

Abstract

Title: Sludge Treatment System and Method The invention relates to a sludge treatment system, particularly for concrete plants, comprising a treatment circuit including: - means for screening homogenized sludge (11); - means for solid-liquid separation (12) of water containing solid particles from the screening means (11); - a handling assembly (2), comprising an articulated arm (21), and a main tool (22) for the articulated arm (21), the main tool (22) comprising a pumping inlet (221), grinding means (222), and water spraying means (223); - pumping means (3) for pumping homogenized sludge through the pumping inlet (221) and for discharging it so as to pass through the screening means (11). Figure for the abstract: Fig. 1

Description

Title of the invention: Sludge treatment system and method technical field

[0001] The field of the invention is that of the design of solutions for the treatment of waste from the manufacture of concrete.

[0002] The invention relates more particularly to a system and a method for treating sludge, in particular sludge from concrete plants. State of the art

[0003] Concrete plants generally include basins, and in particular settling basins, into which wash water is discharged. During the settling of this wash water, sludge consisting of gravel, sand, water and cement is formed.

[0004] This sludge must be removed.

[0005] The most common solution is to use hydrojetting trucks to pump water loaded with solid matter for disposal, and to use earthmovers to clean the settling basins and transport the collected sludge, in a raw state, for burial in a specialized center, without any recovery.

[0006] Some concrete plants use drainage basins to dry the collected sludge as a simple compaction material.

[0007] Finally, a small number of concrete plants have installed fixed treatment systems, incorporating, for example, a sorting screw and a filter press, to directly treat the wash water, which is laden with solid particles. This equipment requires significant investment, dedicated personnel, and site reconfiguration.

[0008] In the field of the invention, systems for treating sludge and concrete residue are known, designed to treat sludge and residue directly from concrete mixer trucks. Such a system is, for example, described in patent document published under number FR2192489A5.

[0009] Such systems do not allow the treatment of sludge from settling basins. Technical problem

[0010] The invention aims in particular to overcome these drawbacks of the prior art.

[0011] More specifically, the invention aims to provide a solution for valorizing sludge from concrete plants, and in particular sludge from basins, and more specifically that from settling basins.

[0012] The invention also aims to provide such a solution which is economical to implement.

[0013] The invention further aims to provide such a solution which can be applied to a pre-existing concrete plant, without involving reconfiguration of the site of the concrete plant, or minimizing this reconfiguration. Summary of the invention

[0014] These objectives, as well as others that will appear subsequently, are achieved through the invention, which relates to a sludge treatment system, particularly for a concrete plant, comprising a treatment circuit including: - means of sieving homogenized sludge; - means of solid-liquid separation of waters loaded with solid particles from the sieving means; characterized in that it comprises a handling assembly, including an articulated arm, and a main tool for the articulated arm, the main tool comprising: - a pumping nozzle; - crushing means including crushing hammers, at least part of the crushing means enclosing at least partially a volume, called the suction volume, into which the pumping mouth opens; - water spraying means having at least one position in which they spray water in the vicinity of the suction volume, the system also includes pumping means designed to pump homogenized sludge through the pumping mouth and to discharge it so that it is passed through the screening means.

[0015] The treatment system according to the invention makes it possible to recover sludge from concrete plants, and more specifically sludge that would be accumulated in a basin of a concrete plant.

[0016] Thanks to its handling assembly, the system makes it possible to homogenize the sludge accumulated in the basin before it can be suctioned, sieved, and then dried. Aggregates can thus be recovered, and a residual dry aggregate can be separated from the water contained within it after sieving.

[0017] This solution does not necessarily require the reconfiguration of a site on which a concrete plant is installed. Indeed, the solution can be implemented on conventional concrete plant sites using basins in which the sludge produced by the operation of the concrete plant is stored.

[0018] According to a preferred embodiment, the grinding means of the main tool include: - a set of rough grinding rollers framing the suction volume; - a secondary finishing grinding unit located in the suction volume.

[0019] Such grinding means make it possible to efficiently grind aggregates that would be formed within the sludge. With surrounding water, or water supplied to the grinding point by these grinding means, the solid particles of the aggregates are resuspended, and homogenization occurs, facilitating pumping and then sieving.

[0020] Advantageously, the water spraying means include at least one spray nozzle ramp movably mounted on the main tool, and means for adjusting the position of the spray nozzle ramp.

[0021] The spray produced by a nozzle ramp allows large areas to be treated, and the orientation of this or these nozzle ramps allows the way in which the aggregates to be homogenized are sprayed to be adjusted.

[0022] According to an advantageous embodiment, the treatment system comprises a road vehicle having a chassis, and in which the articulated arm, and at least part of the treatment circuit are mounted on the chassis, the system having a transport configuration in which the handling assembly and the treatment circuit are contained within an overall perimeter defined by the chassis.

[0023] In this way, the system can be moved between concrete plants to make use of the sludge accumulated in their basins. This greatly reduces the cost of sludge reprocessing for a concrete plant.

[0024] According to an advantageous design, the processing system comprises: - buffer tanks with lifting points using the articulated arm, the chassis with storage locations for the buffer tanks in the system's transport configuration; - ejection chutes for aggregates screened by the screening means, the ejection chutes having a position of use in which they are oriented to eject aggregates outside the overall perimeter defined by the chassis.

[0025] This design allows the treatment system, when in use, to store the screened aggregates from the homogenized sludge screening next to the chassis, and to temporarily store the wastewater or clean water in the buffer tanks. This avoids compromising the chassis dimensions and its load capacity by requiring the water and screened aggregates to be stored on the chassis.

[0026] Preferably, a buffer tank, called the first buffer tank, is designed to receive water loaded with solid particles from screening means of the treatment circuit, the first buffer tank incorporating an agitator.

[0027] This avoids the sedimentation of fine particles suspended in the stored water.

[0028] Advantageously, the vehicle comprises a main engine and a power take-off configured to transmit the motor torque from the main motor to the articulated arm in order to allow its actuation.

[0029] In this way, the system's size is limited.

[0030] The invention also relates to a process for treating sludge from concrete plants, the process comprising: - a sieving stage of sludge from a concrete plant; - a filtration step for water containing solid particles from the sieving step; characterized in that it includes a step of homogenizing solid sludge from a basin of a concrete plant and a step of pumping this homogenized sludge to feed the screening step.

[0031] This process makes it possible to reprocess and valorize the sludge that has been settled and stored in the basin(s) of a concrete plant.

[0032] Preferably, the homogenization step and the pumping step are carried out in the basin by spraying, grinding, and then sucking up the solid sludge.

[0033] According to a preferred feature, the treatment process includes a step of pressing the solid particles from the filtration step.

[0034] Residual solid waste can, for example, be recovered in the form of cakes or bricks. Brief description of the drawings

[0035] Other features and advantages of the invention will become more apparent upon reading the following description of various preferred embodiments of the invention, given by way of illustrative and non-limiting examples, and the accompanying drawings, among which: • [Fig.1] [Fig.1] is a schematic side view representation of a vehicle of the sludge treatment system of an embodiment of the invention; • [Fig.2] [Fig.2] is a simplified schematic representation viewed from above of the sludge treatment system according to an embodiment of the invention; • [Fig.3] [Fig.3] is a schematic representation of the sludge treatment process according to the invention; • [Fig.4] [Fig.4] is a schematic side perspective representation of a main tool in a sludge treatment system handling assembly; • [Fig.5] [Fig.5] is a schematic perspective view from below of a main tool in a sludge treatment system handling assembly. Detailed description

[0036] With reference to figures 1 and 2, a sludge treatment system according to the invention is shown.

[0037] This treatment system is designed to recover value from concrete plant sludge which accumulates in basins of these plants, in particular in settling basins.

[0038] The treatment system includes a treatment circuit intended to treat collected sludge.

[0039] This treatment circuit includes means for screening 11 homogenized sludge.

[0040] By "homogenized sludge" is meant sludge (totally or partially dewatered, or not dewatered), which is mixed, in particular with surrounding water, for example water supernatant to sludge, or water from stirring basins which is water charged with fine particles kept in suspension by stirring, or with brought-in water.

[0041] As will be detailed later, the screening means 11 are supplied with homogenized sludge through a supply line 10.

[0042] These screening means 11 are designed to screen homogenized sludge in order to extract aggregates with pre-defined particle sizes.

[0043] For example, the screening means 11 may include three screens with different mesh sizes to separate aggregates, including gravel with a size of 15 mm to 5 mm, gravel with a size of 5 mm to 2 mm, and sand with a size of 2 mm to 1 mm, the remainder being solid particles suspended in water.

[0044] These sieving means 11 can for example be formed by rotary or vibrating sieves.

[0045] The system also includes ejection chutes 6 for aggregates screened by the screening means 11.

[0046] These ejection chutes 6 have an operating position in which they are oriented to eject aggregates in a predetermined direction.

[0047] For example, rubble bags 61 can be positioned under the discharge ends of the chutes in order to collect gravel and screened sand.

[0048] The treatment circuit also includes solid-liquid separation means 12 for waters loaded with solid particles from the screening means 11.

[0049] In addition, the system includes buffer tanks 5. These buffer tanks are intended to serve as intermediate storage volume in order to compensate for different treatment flow rates between the technical means of the treatment circuit.

[0050] More specifically, the system includes at least a first buffer tank 51 which is designed to receive water loaded with solid particles from the screening means 11 of the treatment circuit.

[0051] The first buffer tank 51 incorporates an agitator (not shown) preventing the sedimentation of suspended solid particles. The system also includes a pump configured to pump the wastewater from this first buffer tank 51 and send it to the solid-liquid separation means 12.

[0052] The solid-liquid separation means 12 include, for example, a solid-liquid separator designed to continuously remove solid particles from contaminated water. The solid-liquid separator preferably uses a centrifuge.

[0053] The solid-liquid separation means 12 make it possible to obtain very low-charge water and solid particles.

[0054] According to the present embodiment, the separated water is redirected to a second buffer tank 52, and can be reused to homogenize sludge, or other.

[0055] The processing circuit further includes means for pressing 13 solid particles from the solid-liquid separation means 12.

[0056] The pressing means 13 in this case comprise two mechanical presses configured to shape the extracted solid particles, for example into cakes or bricks.

[0057] According to the present embodiment, the solid particles from the solid-liquid separation means 12 are conveyed to the mechanical presses by means of a conveyor belt 7. This conveyor belt 7 is mobile between two positions in order to be able to alternately feed the two mechanical presses.

[0058] The processing system also includes a manipulation set 2.

[0059] This manipulation assembly 2 includes an articulated arm 21. This articulated arm comprises a plurality of sections articulated to one another. Such an articulated arm is similar to those of backhoe loaders.

[0060] The manipulation assembly also includes a main tool 22 for the articulated arm 21.

[0061] The handling assembly 2 includes further tools 20, such as a scraper bucket and a crusher bucket, which can be used in synergy with the main tool as explained below.

[0062] The articulated arm 21 is provided with a connecting and manipulating joint located at its end and serving as an interface with the main tool 22 or other tools 20. This connecting and manipulating joint allows, remotely, for the rapid attachment and detachment of a tool, and for the precise tilting of the tool relative to the end of the articulated arm 21. Such a joint and manipulation joint is known by the expression "tiltorotator".

[0063] According to the present embodiment, the processing system comprises a road vehicle 4 having a chassis 41.

[0064] The road vehicle 4 is in this case a modified heavy goods vehicle with a cab 42.

[0065] The articulated arm 21, and at least part of the processing circuit, are mounted on the chassis 4L

[0066] The road vehicle 4 includes a main engine and a power take-off configured to transmit the engine torque from the main engine to the articulated arm 21 to enable its operation. This eliminates the need for a separate engine for the articulated arm 21.

[0067] The system includes a base 210 fixedly mounted on the chassis 41, and the articulated arm 21 is mounted on the chassis 41 via the base 210. The articulated arm 21 is mounted for rotational movement on the base 210.

[0068] The system has a transport configuration in which the handling assembly 2 and the processing circuit are contained within an overall perimeter defined by the chassis 4L. In this way the road vehicle 4 can move between concrete plants on roads open to traffic, without involving heavy logistics.

[0069] In addition, chassis 41 features: - 50 storage locations for 5 buffer tanks in the system's transport configuration; - storage locations for 200 tools 20 and / or the main tool 22.

[0070] For this purpose, the buffer tanks 5 have lifting points using the articulated arm 21 to allow their handling during the commissioning of the system, when the buffer tanks are positioned alongside the road vehicle 4.

[0071] The chassis 41 also has storage compartments 40, such as boxes, for storing various equipment, such as soft bags, high-pressure cleaning tools, ...

[0072] The road vehicle 4 may also have stabilization means 43, such as hydraulic feet, allowing the position of the chassis 41 to be stabilized when the system is used.

[0073] The main tool 22 is now described in more detail with reference to Figures 4 and 5.

[0074] The main tool 22 comprises a body 220 having a lower face 23 through which homogenized sludge is intended to be aspirated.

[0075] This main tool 22 comprises: - a pumping inlet 221; - grinding means 222.

[0076] The pumping port is located at the lower face 23 of the body 220.

[0077] According to the present embodiment, the pumping mouth 221 is divided into a plurality of openings distributed around a cylindrical block of revolution.

[0078] It is conceivable that the pumping mouth is formed by a simple cylindrical opening.

[0079] The main tool 22, and the pumping mouth 221, define a suction volume into which the pumping mouth 221 opens. This suction volume is open to allow the entry of sludge into it so that it can be sucked up.

[0080] This suction volume is located under the lower face 23.

[0081] The ability of the main tool 22 to be moved and oriented using the articulated arm allows the suction volume to be positioned where sludge can be suctioned.

[0082] The system also includes pumping means 3 intended to pump homogenized sludge through the pumping mouth 221 and to discharge it so as to be passed through the screening means 11.

[0083] According to the present embodiment, the main tool 22 incorporates these pumping means 3 as illustrated in Figures 4 and 5. These pumping means 3 are formed by a pump mounted on the body 220.

[0084] The pumping means 3 are coupled to the supply line 10 which extends from the pump.

[0085] According to another conceivable embodiment, the pump could be mounted on the chassis 41 of the road vehicle 4.

[0086] The grinding means 222 comprise grinding hammers (illustrated schematically). These grinding hammers are mounted to rotate freely on rollers mounted to rotate on the body 220, the rollers being driven in rotation by motor means which results in grinding by the grinding hammers.

[0087] At least part of these grinding means 222 frame at least partially the suction volume into which the pumping mouth 221 opens.

[0088] These grinding means 222 form agitators producing a homogenization of what is to be pumped.

[0089] With reference to Figures 4 and 5, the grinding means 222 of the main tool 22 comprise: - a set of 2221 rough grinding rollers framing the suction volume; - a secondary finishing grinding unit 2222 located in the suction volume.

[0090] The rough grinding roller assembly 221 comprises two rollers extending parallel to each other, on either side of the suction volume. These two rollers extend over essentially the entire length of the body 220. These rollers are driven in rotation so as to expel ground sludge towards the suction volume.

[0091] The pumping mouth 221 is centered between the two rough grinding rollers 221 as can be seen in [Fig.5].

[0092] According to the present embodiment, the secondary finishing grinding assembly 2222 comprises a single finishing roller that is also mobile in rotation.

[0093] According to other conceivable embodiments, the rough grinding roller assembly 2221 could include more than two rollers and the secondary finishing grinding assembly 2222 could include more than one roller.

[0094] The secondary finishing grinding assembly 2222 is centered between the two rollers of the rough grinding roller assembly 221.

[0095] The main tool 22 also includes water spraying means 223 having at least one position in which they spray water near the suction volume.

[0096] The spraying means 223 are coupled to a water source and can benefit from the pumping means 3 by means of a pumping circuit independent of a main circuit allowing the aspiration of homogenized sludge.

[0097] The water source may correspond to an on-site water supply, or to a reserve of "clean" water, for example contained in a buffer tank 5.

[0098] The water spraying means 223 include at least one spray nozzle 2231 mounted movably on the main tool 22, and means for adjusting the position of the spray nozzle 2231.

[0099] The adjustment means 2233 are formed by jacks allowing the angular position of the ramps 2231 to be modified.

[0100] These ramps 2231 are rotationally movable between a position in which the spray nozzles 2232 are spread apart ([Fig.5]), and a position in which the spray nozzles 2232 are directed as much as possible towards a space located in front of the lower face 23 of the body 220. The ramps 2231 can also adopt intermediate positions such as that illustrated by [Fig.4].

[0101] The main tool 22 described above allows for the homogenization of completely or partially settled and solidified sludge.

[0102] In support of this main tool 22, the scraper bucket and the shredding bucket can also be used to: - to bring together and pile up sludge using the scraper bucket, with a view to homogenizing it using the main tool 22; - only grind specific elements, using the dedicated grinding bucket.

[0103] The system described above implements the treatment process according to the invention. The technical functions of the system's technical features thus correspond to the process steps described below. Naturally, the function of the features described with reference to the system is implemented by steps of the process described below.

[0104] With reference to [Fig.3], the process for treating sludge from concrete plants is described below.

[0105] The process comprises: - a homogenization step El of solid sludge from a concrete plant basin, preferably a settling basin; - a pumping step E2 of these homogenized sludges to feed the screening step E3 - a screening step E3 of the homogenized sludge; - a filtration step E4 of water loaded with solid particles from the sieving step; - a pressing step E5 of the solid particles from the filtration step E4.

[0106] According to the present embodiment, the homogenization step E1 and the pumping step E2 are carried out in the basin by spraying, grinding, and then suctioning the solid sludge. This is performed by the main tool 22 of the handling assembly 2.

[0107] The process described above is implemented on a road vehicle 4 by carrying out a temporary storage of at least a majority of the by-products obtained (gravel, sand, loaded or clean water, and pressed waste) on the side of the road vehicle 4, in a system use configuration.

[0108] Of course, in a transport configuration of the system all the technical means of the system are carried in the road vehicle 4 and contained within the overall perimeter of the chassis 41 in order to allow the road vehicle 4 to use roads open to traffic.

[0109] The system and method according to the invention form an economical solution to be implemented to valorize sludge from concrete plants, and in particular sludge from basins, and more specifically that from settling basins.

Claims

Demands

1. Sludge treatment system, in particular for concrete plants, comprising a treatment circuit including: - means for screening homogenized sludge; - means for solid-liquid separation (12) of water loaded with solid particles from the screening means (11); characterized in that it includes a handling assembly (2), including an articulated arm (21), and a main tool (22) for the articulated arm (21), the main tool (22) including: - a pumping inlet (221); - grinding means (222) including crushing hammers, at least a part of the grinding means (222) at least partially enclosing a volume, called the suction volume, into which the pumping inlet (221) opens;- water spraying means (223) having at least one position in which they spray water near the suction volume, the system also comprising pumping means (3) intended to pump homogenized sludge through the pumping mouth (221) and to discharge it so as to be passed through the screening means (11).

2. Processing system according to the preceding claim, characterized in that the grinding means (222) of the main tool (22) comprise: - a set of rough grinding rollers (2221) framing the suction volume; - a secondary finishing grinding set (2222) located in the suction volume.

3. Processing system according to any one of the preceding claims, characterized in that the water spraying means (223) comprise at least one spray bar (2231) of spray nozzles (2232) movably mounted on the main tool (22), and means for adjusting (2233) the position of the spray bar (2231) of spray nozzles (2232).

4. A treatment system according to any one of the preceding claims, characterized in that it comprises a road vehicle (4) having a chassis (41), the articulated arm (21), and at least part of the processing circuit being mounted on the chassis (41), and in that it has a transport configuration in which the handling assembly (2) and the processing circuit are contained within an overall perimeter defined by the chassis (41).

5. Processing system according to the preceding claim, characterized in that it comprises: - buffer tanks (5) having lifting points using the articulated arm (21), the chassis (41) having storage locations for the buffer tanks (5) in the transport configuration of the system; - ejection chutes (6) for aggregates screened by the screening means (11), the ejection chutes (6) having an operating position in which they are oriented to eject aggregates outside the overall perimeter defined by the chassis (41).

6. Treatment system according to the preceding claim, characterized in that a buffer tank (5), referred to as the first buffer tank (51), is designed to receive water loaded with solid particles from the screening means (11) of the treatment circuit, the first buffer tank (51) incorporating an agitator.

7. Processing system according to any one of claims 4 to 6, characterized in that the road vehicle (4) comprises a main engine and a power take-off configured to transmit the engine torque from the main engine to the articulated arm (21) in order to enable its actuation.

8. Process for treating sludge from concrete plants, the process comprising: - a screening step (E3) of sludge from a concrete plant; - a filtration step (E4) of water loaded with solid particles from the screening step; characterized in that it comprises a homogenization step (E1) of solid sludge from a basin of a concrete plant and a pumping step (E2) of this homogenized sludge to feed the screening step (E3).

9. Treatment process according to the preceding claim, characterized in that the homogenization step (E1) and the pumping step (E2) are carried out in the basin by spraying, grinding, and then suctioning the solid sludge.

10. Processing method according to any one of claims 8 and 9, characterized in that it comprises a pressing step (E5) of the solid particles from the filtration step (E4).

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