IMPROVED EFFICIENCY SLUDGE TREATMENT SYSTEM

Abstract

The present invention relates to a sludge treatment system employing a flocculant comprising a circuit (C2) for circulating sludge to be treated, means (25) for injecting a flocculant in liquid form into said circuit (C2), wherein said circuit (C2) comprises at least a first static mixer (26, 28) so as to generate turbulence in the flow of a sludge stream and an agglomeration device downstream of the first diaphragm (26) in the direction of the sludge flow, and wherein the flocculant injection means (25) are configured to inject the flocculant into the circuit (C2) through the first diaphragm (26). [Fig. 1]

Description

Title of the invention: ENHANCED EFFICIENCY SLUDGE TREATMENT SYSTEM TECHNICAL FIELD AND PRIOR ART

[0001] The present invention relates to a sludge treatment system with improved efficiency, particularly resulting from the extraction of materials from pipes and wells by water injection and pumping.

[0002] When you want to unblock a blocked pipe, pressurized water is injected into it, which dissolves the materials, thus forming sludge, which is then sucked up and collected in a tank.

[0003] This type of device is generally installed on a sanitation vehicle which has a water tank and a sludge collection tank. Generally, the sludge is filtered to separate the larger solid particles from the water. The water is then returned to the water tank for reuse.

[0004] In order to improve water recycling, it is known to inject a flocculating agent into the sludge, to agglomerate the remaining solid particles and facilitate their separation. The separation of the agglomerated solid particles and the water is then obtained by means of a filtration system.

[0005] It is desirable to improve the effectiveness of such treatment. Statement of the invention

[0006] It is therefore an object of the present application to provide a sludge treatment system offering improved efficiency.

[0007] In the present application, "sludge" means the mixture of solid materials and water.

[0008] The aim stated above is achieved by a sludge treatment system comprising a circuit for circulating the sludge to be treated, a reservoir of at least one flocculation agent, means for injecting said agent into the circuit, said circuit comprising at least one static mixer and an agglomeration device downstream of the diaphragm, the injection means being configured to inject the flocculation agent at the static mixer.

[0009] The static mixer may comprise a plate static mixer and / or a helical static mixer.

[0010] Preferably, the static mixer is a plate static mixer and the injection takes place into or just downstream of the static mixer.

[0011] The static mixer generates turbulence, the flocculating agent is quickly mixed with the sludge. The sludge and the flocculating agent then pass through the device agglomeration, which promotes the agglomeration of particles and the generation of larger particles.

[0012] Preferably, another helical static mixer is provided between the plate static mixer and the agglomerating device, which further improves the quality of the mixture.

[0013] Thus, thanks to the invention, the homogeneity of the mixture between the flocculation agent and the fluidic solution is significantly improved, which allows increased agglomeration of the particles and therefore more effective separation of the solid particles and water.

[0014] The invention makes it possible to reduce the quantity of water required since its recycling is improved.

[0015] In a particularly advantageous example, the system comprises the injection of a coagulation agent upstream of the injection of the flocculation agent, the addition of such an agent facilitates the bringing together of the finer particles.

[0016] Preferably, the flocculation agent is premixed with water before being injected into the circuit. Very advantageously, the premixing is carried out by means of a coil device.

[0017] The system according to the invention can be integrated into a sanitation vehicle.

[0018] The present invention then relates to a sludge treatment system using a flocculant, comprising a circuit intended to circulate sludge to be treated, means for injecting a liquid flocculant solution into said circuit. Said circuit comprises at least a first static mixer so as to generate turbulence in the flow of a sludge stream, an agglomeration device downstream of the first static mixer in the flow direction of the sludge stream, and the means for injecting the liquid flocculant solution being configured to inject the flocculant into the circuit at the first static mixer.

[0019] Preferably, the first static mixer is a first plate static mixer.

[0020] The means for injecting a flocculant are very advantageously configured to inject the liquid flocculant solution into the first static plate mixer.

[0021] The sludge treatment system may comprise a first helical static mixer between the first plate static mixer and the agglomeration device.

[0022] In an exemplary embodiment, the sludge treatment system comprises means for injecting a coagulant upstream of the first static mixer. The circuit may comprise a second static plate mixer and a second helical static mixer, the means for injecting a coagulant being configured to inject the coagulant at the second static plate mixer.

[0023] The agglomeration device advantageously comprises an enclosure extending longitudinally comprising a cylindrical part with a circular section, and a conical part, said enclosure comprising at one longitudinal end a feed orifice in the cylindrical part, and a discharge outlet at a second longitudinal end located at the top of the conical part, the feed orifice being such that the flow of sludge is injected into the enclosure substantially tangentially to the wall of the cylindrical part.

[0024] Preferably, the sludge treatment system comprises a system for premixing a flocculating agent with water so as to form the liquid flocculant solution. The premixing system may comprise a water supply inlet, a flocculating agent supply inlet and a mixing circuit.

[0025] Another subject of the present application is a sludge treatment installation comprising a water tank, a sludge tank, a sludge treatment system according to the invention, at least one cyclone separator, an inlet of the treatment system circuit being connected to the outlet of the sludge tank and the outlet of the treatment system circuit being connected to the cyclone separator.

[0026] The sludge treatment installation advantageously comprises a turbidimeter downstream of the cyclone separator and / or at a drain outlet of the water tank, and / or means for ultraviolet disinfection of the water at the drain outlet.

[0027] Another object of the present application is a sanitation vehicle comprising an installation according to the invention, means for injecting water into an area to be cleaned so as to form sludge, and means for sucking up the sludge. Brief description of the drawings

[0028] The present application will be better understood with the aid of the description which follows and the attached drawings in which: - [Fig.l] is a schematic representation of an exemplary embodiment of a sludge treatment installation implementing an example of a treatment system according to the invention, - [Fig.2] is a schematic representation of a premixing system of the treatment system according to the invention, - [Fig.3] is a front view of an example of a diaphragm that can be implemented in the treatment system according to the invention, - [Fig.4] is a side view of an example of a static mixer that can be implemented in the treatment system according to the invention, - [Fig.5] is a schematically represented longitudinal sectional view of an example of an agglomeration device that can be implemented in the treatment system according to the invention. DETAILED DESCRIPTION OF EMBODIMENTS

[0029] In [Fig. 1], a sludge collection installation can be seen implementing an example of a treatment system according to the invention.

[0030] The installation is intended to collect solid materials, for example contained in pipes, wells or the like. In general, these solid materials at least partially block the pipe or well. In order to facilitate the suction of these solid materials, water is injected into the area to be cleared and the water and the solid materials forming sludge are sucked up.

[0031] The aim of the invention is to treat the sludge thus sucked up in order to recycle the water contained therein.

[0032] The installation comprises a sludge tank 1, a water tank 2, a water injection system 6 in the area to be cleaned, for example a CA pipeline, in order to facilitate the suction of the sludge and suction means 4 for the mixture of water and sludge contained in the pipeline.

[0033] The water injection system 6 comprises a high pressure pump 7.

[0034] The water tank has an outlet 2.1 for using water for the treatment system and an outlet 2.2 for discharging water and supplying the high-pressure pump which will be described later. The outlet 2.1 is equipped with a valve 3.

[0035] The valves are preferably pneumatic valves controlled either from a control panel by the user or automatically by a control unit which manages the different cycles autonomously. Alternatively, solenoid valves can be implemented.

[0036] In the example shown, the installation comprises a single tank whose internal volume is separated in two by a wall 8, thus forming the sludge tank 1 and the water tank 2.

[0037] The wall 8 can be movable, allowing the volume of the two reservoirs to be adjusted according to the volume of their contents.

[0038] The installation includes a sludge treatment system for separating the water from the solid matter and thus recycling the water so that it can be reused, for example to continue unblocking the pipes without having to fill the water tank.

[0039] The installation includes a circuit Cl intended to treat the sludge.

[0040] The circuit C1 is connected at the input to a discharge outlet 9 of the sludge tank 1 and at the output to at least one separator 14.

[0041] The circuit comprises a pump 12 intended to circulate the sludge in the circuit, the cyclone-type separator 14 intended to separate the water from the solid matter. The circuit C1, at the outlet of the cyclone separator 14, comprises a branch connected to the sludge tank to return the solid matter thereto and a branch connected to the water tank to return the water thereto. The circuit C1 comprises a first portion C1.1 between the inlet of the circuit and pump 12, a second portion Cl.2 between the pump and the cyclone separator, a third portion Cl.3 between the cyclone separator and the sludge tank and a fourth portion Cl.4 between the cyclone separator and the water tank.

[0042] Preferably, a filtration system 20, for example of the filter drum type, is provided at the discharge outlet 9 of the sludge tank 1 to ensure a first filtration of the sludge so as to retain the largest particles in the sludge tank.

[0043] The treatment system according to the invention S is configured to improve the separation of solid matter from water. For this, it comprises means for injecting a flocculation agent into the sludge in order to cause the agglomeration of the solid particles with each other and facilitate their separation. The use of flocculation agents for the treatment of sludge is well known and will not be described in detail.

[0044] In this example, the system is mounted between the inlet of circuit C1 and pump 12, in bypass of portion C1.1 of circuit 10.

[0045] According to the invention, the treatment system comprises a circuit C2 connected at the inlet to the circuit C1 by a three-way valve 22 making it possible to direct the sludge towards the portion C1.1 or towards the circuit C2, and at the outlet to the circuit C1 upstream of the pump 12 by a three-way valve 24. The control of the valves 3, 22 and 24 makes it possible either to isolate the circuit C2 and to circulate the sludge in the portion C1.1, or to circulate the sludge in the circuit C2, or to circulate water in the circuit C2 or in the circuit C1 for rinsing them.

[0046] This example is in no way limiting and a processing system without the possibility of short-circuiting the circuit C2 does not depart from the scope of the present invention.

[0047] Circuit C2 comprises means for mixing the flocculation agent and the sludge to optimize the effectiveness of the flocculation agent.

[0048] The circuit C2 comprises means 25 for injecting a flocculation agent comprising a flocculation agent reservoir 27 and a pump 29 connected to the circuit C2. Very advantageously, the injection means 25 comprise a system SP for ensuring premixing of the flocculation agent with water before its injection into the circuit C2. Preferably, the water comes from the water reservoir 2. For this, a pipe 23 connects the water reservoir to the outlet of the flocculation agent reservoir 27 and a pump 30 ensures the conveyance of the water to the premixing system SP. Alternatively, a system using a water reservoir separate from the water reservoir 2 does not depart from the scope of the present invention.

[0049] This step is referred to as "premixing" because it takes place before mixing the flocculating agent with the sludge. The mixture obtained at the outlet of the premixing system is a liquid flocculant solution and will be referred to as "flocculant" for reasons of simplicity.

[0050] In a particularly advantageous manner, the SP premixing system comprises at least one coil receiving the flocculation agent and the water at the inlet.

[0051] In [Fig.2], a schematic representation of a preferred embodiment of the SP premixing system can be seen.

[0052] The premixing system comprises an alternation of straight portions and coils, and one or more changes of section. In this example, the premixing device comprises three straight sections D1, D2 and D3 connected by two coils S1 and S2. The coils generate vortices. The inventors have found that this alternation of straight portions and coils significantly improves the mixing of the flocculating agent in the water.

[0053] The number of straight portions and coils is in no way limiting and is chosen, for example, as a function of the desired premix efficiency, the space available and the quantity of flocculation agent to be premixed.

[0054] Advantageously, the inlet of the device comprises one or more elbows 31 and one or more changes in section, in particular downstream of the injection of water and flocculation agent, further improving the premixing.

[0055] The injection device also has the advantage of ensuring continuous premixing of the flocculation agent with the water, and continuous injection into the circuit C2, which makes the sludge treatment faster. Such a system avoids having to stop the installation in order to fill a tank containing the water and flocculation agent mixture, as is done in existing installations.

[0056] The mixing system comprises at least one first static mixer and advantageously two first static mixers in series.

[0057] The first static mixers can be chosen from the plate static mixer and the helical static mixer.

[0058] In a preferred example, the injection means inject the flocculant at the static mixer plate 26, hereinafter referred to as the “diaphragm” for simplicity. “At the diaphragm” means in or just after the diaphragm. Preferably, the injection means are integrated into the diaphragm, more particularly the injector(s) 26.1 are integrated into the diaphragm plate as shown diagrammatically in [Fig. 3].

[0059] In [Fig. 3], a front view of an example of a diaphragm 26 that can be implemented in the present invention can be seen. It generates strong turbulence downstream, which causes a first dilution of the flocculant in the sludge.

[0060] An example of a helical static mixer 28 is shown in [Fig.4]. The helical static mixer receives the flocculant and sludge mixture. It is configured to ensure separation of the flow and its grouping, as well as rotation of the flow around the axis of the pipeline. The arrows F symbolize the flows in the mixer static. The static mixer 28 comprises fins 28.1 arranged in the flow duct and shaped so as to ensure the separation of the flow, its rotation and its grouping.

[0061] The action of the diaphragm 26 and the static mixer 28 significantly improves the homogeneity of the mixture. Now the action of the flocculant which is to ensure an agglomeration of the particles between them is particularly effective when the mixture is homogeneous. This therefore results in obtaining a homogeneous mixture quickly between the sludge and the flocculant, and an improved action of the latter.

[0062] The number of elements allowing the separation of the flow, its rotation and its grouping is chosen according to the installation, in particular according to the volume to be treated, in order to achieve a homogeneous mixture. This agglomerate of particles is called "floc".

[0063] Preferably, the treatment system comprises, downstream of the first diaphragm 26, a device 32, designated an agglomeration device, further promoting the formation of large flocs which are even more easily separable from the water. In [Fig.5], a representation of the agglomeration device 32 can be seen.

[0064] The agglomeration device 32 comprises an enclosure 34 with a longitudinal axis X, having a first cylindrical part 36 with a circular section and a second conical part 38. The device comprises a supply inlet 41 of the enclosure oriented so as to ensure injection of the flow into the first cylindrical part 36, advantageously blades (not shown) making it possible to facilitate the generation of a vortex around the axis X, and an evacuation outlet 39 located in the lower part of the device in the representation of [Fig. 5], more particularly at the free end of the second conical part 38 in the axis of the enclosure.

[0065] The operation of the agglomeration device 32 is as follows.

[0066] The flow of fluid leaving the static mixer 28 is injected tangentially to the wall of the first cylindrical part 36, which generates a swirling flow in the enclosure around the axis X. The flocs are then pushed radially outwards and then are brought closer to each other due to the flow towards the discharge outlet 39. The flocs P being brought closer to each other, this results in an agglomeration of flocs between them and therefore the formation of flocs P' of larger dimensions, which are more easily separable from the water for example by a cyclonic separator.

[0067] Alternatively, the system comprises two first static plate mixers in series, two first helical static mixers in series. Alternatively, the first helical static mixer is upstream of the first static plate mixer and the injection of the flocculant takes place between them.

[0068] In a particularly advantageous manner, the treatment system also comprises means 40 for injecting a coagulating agent into the circuit upstream of the injection of the flocculant.

[0069] The injection means 40 comprise a coagulant reservoir 42, an injection pump 44 and an injection tube 43 which connects the reservoir to the circuit C2 upstream of the diaphragm 26. Very advantageously, the circuit C2 also comprises at least a second static mixer at which the coagulant is injected. The second static mixer preferably comprises a diaphragm 46. Preferably, the coagulant is injected into the diaphragm 46, in a similar manner to the diaphragm 26, improving the dilution of the coagulant in the sludge. Alternatively, the coagulant is injected just downstream of the diaphragm 46.

[0070] Also advantageously, a helical static mixer 48 is provided in front of the diaphragm 46, further improving the homogeneous mixing between the sludge and the coagulant.

[0071] The coagulant comprises, for example, metal salts, generally iron or aluminum salts, for example A1C13, making it possible to eliminate or at least reduce the colloidal repulsions between the particles, which facilitates the formation of flocs under the action of the flocculant.

[0072] The diaphragm 46 may be similar to the diaphragm 26.

[0073] The helical static mixer 48 may be similar to the helical static mixer 28.

[0074] Alternatively, the system comprises two second static plate mixers in series, two second helical static mixers in series. Alternatively, the second helical static mixer is upstream of the second static plate mixer and the injection of the flocculant takes place between them.

[0075] Also advantageously, the installation comprises means for monitoring and treating the recycled water 49 comprising for example a turbidimeter 53 which measures the turbidity of the water.

[0076] The water tank comprises a discharge outlet 2.2, a valve 51 for closing the outlet 2.2, a filter 52 and the turbidimeter 53.

[0077] For example, the filter 52 is such that it retains particles larger than 5 μm. The filter 52 is preferably a backwash filter.

[0078] Advantageously, the means 49 comprise a water treatment device, for example an ultraviolet disinfection lamp 54. The ultraviolet treatment makes it possible to make the water contained in the water tank comply with the requirements for being discharged into a drainage system.

[0079] In the example shown, a circuit C3 making it possible to short-circuit the turbidimeter 53 and the water treatment device is provided between the valve 51 and a higher valve additional 58 which is provided between the water treatment device 52 and the ultraviolet lamp 54.

[0080] A turbidimeter 56 is advantageously arranged on the portion C1.4 at the outlet of the cyclone separator. Very advantageously, it may be provided to check the turbidity of the recycled water to adjust the quantity of flocculant and / or coagulant to be injected into the circuit C2. Preferably, an electronic control unit automatically ensures the adjustment of the injection of the flocculant and possibly the coagulant according to the turbidity measurement. The quantities injected are for example managed by the control of the pumps, which makes it possible to limit the quantity of flocculant and possibly the coagulant to the necessary quantities.

[0081] An example of operation of the installation will now be described.

[0082] Water taken from the water tank 2 is injected into a pipe to be evacuated CA, the sludge thus formed is sucked up and collected in the sludge tank 1.

[0083] The valve 22 is controlled so as to connect the sludge tank 1 with the circuit C2, the pump 12 is activated so as to circulate the sludge in the circuit C2. Simultaneously, the pumps 29 and 30 are activated to inject the flocculant and the water into the premixing system SP, the solution thus produced is injected into the diaphragm 26. The pump 44 is also activated to inject the coagulant into the diaphragm 46.

[0084] The sludge is mixed first with the coagulant, then second with the flocculant, which causes the formation of flocs. The sludge containing the flocs is then injected into the agglomeration device, which has the effect of agglomerating the flocs together.

[0085] The sludge is then conveyed to the cyclonic separator 14 which ensures separation of the water, which is returned to the water tank 2, and the solid particles P', which are discharged into the sludge tank 1.

[0086] By controlling valves 3, 22 and 24, it is possible to ensure rinsing of circuit C2 by circulating water from the water tank to the cyclone separator 14.

[0087] It is also possible to back-rinse the filter 20 by controlling the valves so that the water circulates from the water tank directly to the outlet of the mud tank.

[0088] Alternatively, the entire treatment system may be arranged between the pump 12 and the cyclone separator 14. According to another alternative, the treatment system is arranged between the cyclone separator 14 and the water tank.

[0089] Alternatively, the flocculant injection means 25 can inject the flocculant directly into the sludge tank and / or directly into the water tank.

[0090] It will be understood that the sludge treatment system is a system in its own right which can be integrated during manufacturing into a processing facility or manufactured independently and connected to a facility as required.

[0091] The sludge treatment installation comprising a treatment system according to the invention may be fixed or mobile, for example mounted on a sanitation vehicle.

Claims

Claims

1. Sludge treatment system using a flocculant, comprising a circuit (C2) intended to circulate sludge to be treated, means (25) for injecting a liquid flocculant solution into said circuit (C2), in which said circuit (C2) comprises at least a first static mixer so as to generate turbulence in the flow of a sludge stream, an agglomeration device (32) downstream of the first static mixer (26, 28) in the direction of flow of the sludge stream, and in which the means for injecting the liquid flocculant solution (25) are configured to inject the flocculant into the circuit (C2) at the first static mixer (26).

2. The sludge treatment system of claim 1, wherein the first static mixer is a first plate static mixer (26).

3. A sludge treatment system according to claim 2, wherein the flocculant injection means is configured to inject the liquid flocculant solution into the first static plate mixer (26).

4. A sludge treatment system according to claim 2 or 3, comprising a first helical static mixer (28) between the first plate static mixer and the agglomeration device (32).

5. Sludge treatment system according to one of claims 1 to 4, comprising means for injecting a coagulant upstream of the first static mixer.

6. A sludge treatment system according to claim 5, wherein the circuit (C2) comprises a second static plate mixer (46) and a second helical static mixer (48), the coagulant injection means being configured to inject the coagulant at the second static plate mixer (46).

7. A sludge treatment system according to one of claims 1 to 6, wherein the agglomeration device (32) comprises a longitudinally extending enclosure (34) comprising a cylindrical portion (36) of circular cross-section, and a conical portion (38), said enclosure (34) comprising at one longitudinal end a feed orifice in the cylindrical portion (36), and a discharge outlet at a second longitudinal end located at the top of the conical portion, the orifice feed being such that the flow of sludge is injected into the enclosure (34) substantially tangentially to the wall of the cylindrical part (36).

8. A sludge treatment system according to one of claims 1 to 7, comprising a system for premixing a flocculating agent with water so as to form the liquid flocculant solution.

9. A sludge treatment system according to claim 8, wherein the premixing system comprises a water supply inlet, a flocculating agent supply inlet and a mixing circuit.

10. Sludge treatment installation comprising a water tank (2), a sludge tank (1), a sludge treatment system according to one of the preceding claims, at least one cyclone separator (14), in which an inlet of the circuit (C2) of the treatment system is connected to the outlet of the sludge tank and the outlet of the circuit of the treatment system is connected to the cyclone separator (14).

11. Sludge treatment installation according to claim 10, comprising a turbidimeter downstream of the cyclone separator and / or at a drain outlet of the water tank, and / or means for ultraviolet disinfection of the water at the drain outlet.

12. Sanitation vehicle comprising an installation according to the preceding claim, means for injecting water into an area to be cleaned so as to form sludge, and means for sucking up the sludge.

Images