Apparatus And Process For Flocculation Of Solids Fractions Of A Solid-Liquid Mixture

Abstract

The present invention relates in particular to an apparatus for flocculation of solids fractions of a solid-liquid mixture, in particular sludge or gray water, having a mixing sector (6, M) configured for conducting the solid-liquid mixture having a first mixing unit (5) having a static mixer (14) adapted for admixing a first flocculation agent and having a second mixing unit (7) fluidly connected in series with the first mixing unit (5) having a dynamic mixer (16, 18) adapted for admixing a second flocculation agent into the mixing sector (6, M).

Claims

1. An apparatus (2) for flocculating solids fractions of a solid-liquid mixture, more particularly sludge or graywater, comprising a mixing sector (6, M) designed for conducting the solid-liquid mixture and comprising a first mixing unit (5), having a static mixer (14, 17, P) adapted for admixing a first flocculating agent (F), and a second mixing unit (7), connected in series fluidically with the first mixing unit (5) and optionally sited fluidically downstream, having a dynamic mixer (16, 18) adapted for admixing a second flocculating agent (F2) to the mixing sector (6, M).

2. The apparatus (2) as claimed in claim 1, wherein the static mixer (14) comprises one or more impact means (17), designed in the volume of the mixing sector (6, M), and/or the dynamic mixer (16) comprises one or more mixing rotors (18, 32, 33) protruding into the volume of the mixing sector (6, M) and coupled to a motor drive unit.

3. The apparatus (2) as claimed in claim 2, wherein the one or more impact means (17) is at least one of the at least one impact plate (17), wherein the at least one impact plate has an impact surface (P) which is disposed transversely, to the flow traversal direction (D) resulting for the solid-liquid mixture in regular operation, and/or wherein at least one of the at least one impact plate (17), is disposed centrally in relation to a cross-sectional area of the mixing sector (6, M) that exists at the assembly location of the impact plate (17), and/or wherein the free cross-sectional area of the mixing sector (6, M) at the assembly location of the impact plate (17), is 5 to 7 times, more the impact plate area (P), measured transversely to the flow traversal direction (D).

4. The apparatus as claimed in any of claim 1, wherein the first mixing unit (5) comprises a first supply unit (13), designed for supplying the first flocculating agent (F) to the mixing sector (6, M), having at least one first supply opening (35), sited fluidically upstream of the static mixer (14), for the first flocculating agent (F) to the mixing sector (6, M), and/or wherein the second mixing unit (7) comprises a second supply unit (15), designed for supplying the second flocculating agent (F2) to the mixing sector (6, M), having at least one second supply opening (35), sited fluidically upstream of the dynamic mixer (16), for the second flocculating agent (F2) to the mixing sector (6, M), wherein the first supply unit (13) optionally comprises a first supply lance (13), protruding into the mixing volume defined by the mixing sector (6, M

5. An apparatus (2) for admixing flocculating agents (F) into a solid-liquid mixture comprising a mixing sector (6, M) designed for conducting the solid-liquid mixture and comprising a first (5) and a second (7) mixing unit, wherein the second mixing unit (7) is sited fluidically downstream of the first mixing unit (5), and the first mixing unit (5) is adapted for admixing a first flocculating agent (F) to the mixing sector (6, M), and the second mixing unit (7) is adapted for admixing a second flocculating agent (F2) to the mixing sector (6, M), wherein the first flocculating agent (F) comprises a carbonate and/or calcium salt, and the second flocculating agent (F2) comprises at least one acrylamide-free polymer.

6. The apparatus (2) as claimed in claim 5, wherein a distance, measured in flow traversal direction (D), between first supply opening (35) and mixer (14, 17, P) of the first mixing unit (5) and/or between second supply opening (34, 35) and mixer (18, 32) of the second mixing unit (7) is 0.6 to 1.2 times, the free cross section of the mixing sector (6, M) at the location of the first (5) or second (7) mixing unit, respectively, and/or wherein a distance, measured in flow traversal direction (D), between the mixer (14, 17, P) of the first mixing unit (5) and second supply opening (34, 35) is between 0.8 and 1.2 times the free diameter (d.sub.6) of the mixing sector (6, M) at the location of the first mixing unit (5) and/or at the location of the second supply opening (34, 35).

7. The apparatus as claimed in claim 5, wherein the polymer is an anionic or cationic polymer and/or wherein the polymer comprises a polyelectrolyte.

8. A process for flocculating solids fractions of a solid-liquid mixture, more particularly sludge or graywater comprising the steps of conducting the solid-liquid mixture through a mixing sector (6, M), and admixing a first flocculating agent (F) to the solid-liquid mixture in the mixing sector (6, M) by means of a static mixer (14, 17, P) of 2 first mixing unit (5), and admixing a second flocculating agent (F2) to the solid-liquid mixture in the mixing sector (6, M) by means of a dynamic mixer (16, 18, 32, 33) of a second mixing unit (7), optionally sited downstream, and connected fluidically in series to the first mixing unit (5).

9. A process for flocculating solids fractions of a solid-liquid mixture, more particularly sludge or graywater, as claimed in claim 8, wherein the solid-liquid mixture is conveyed through the mixing sector (6, M), and wherein the solid-liquid mixture in the mixing sector (6, M) is admixed first with a or the first flocculating agent, comprising a carbonate and/or calcium salt, and then, fluidically downstream, with a or the second flocculating agent comprising at least one acrylamide-free polymer.

10. The process as claimed in claim 8, wherein the first flocculating agent (F) is supplied to the solid-liquid mixture via a first supply unit (13) sited upstream of the static mixer (14, 17, P) or, of a mixer (14, 17, P) of the first mixing unit (5), and/or wherein the second flocculating agent (F2) is supplied to the solid-liquid mixture via a second supply unit (15), sited fluidically upstream of the dynamic mixer (16, 18, 32, 33) or, of a mixer (16, 18, 32, 33) of the second mixing unit (7), and/or wherein the first flocculating agent (F) is supplied to the solid-liquid mixture via a first supply lance (13) protruding into the mixing volume defined by the mixing sector (6, M), and/or wherein the second flocculating agent (F2) is supplied to the solid-liquid mixture via a second supply lance (15), which protrudes into the mixing volume defined by the mixing sector (6, M), and/or wherein the first and/or second flocculating agents (F, F2) are/is supplied at a position sited approximately centrally in the free cross section of the mixing sector (6, M), and/or wherein the first and/or second flocculating agents (F, F2) is or are supplied to the solid-liquid mixture with a directional component running transversely, to the flow traversal direction (D) of the solid-liquid mixture that prevails at the respective location of supply in the mixing sector (6, M), and/or wherein a flow-technical distance in flow traversal direction (D) of the solid-liquid mixture between location (13, 15) of the addition of the first and/or second flocculating agents (F, F2) and the mixer of the respective first or second mixing unit (5, 7) is 0.6 to 1.2 times, more particularly 0.74 times, the free diameter (d6) of the mixing sector (6, M) measured at the location of the first or second mixing unit (5, 7), respectively, and/or wherein a flow-technical distance between location (15, 35) of the addition of the second flocculating agent (F) and first mixing unit (5), is between 0.8 and 1.2 times the free diameter (d6) of the mixing sector (6, M) at the location of the first mixing unit (5) and/or at the location (15, 35) of the addition.

11. The apparatus (2) as claimed in claim 2, wherein the one or more impact means (17) are impact plates (17).

12. The apparatus (2) as claimed in claim 3, wherein the impact surface is disposed perpendicularly.

13. The apparatus (2) as claimed in claim 3, wherein the free cross-sectional area of the mixing sector (6, M) at the assembly location of the impact plate (17) is 6.25 the impact plate area (P), measured transversely to the flow traversal direction (D).

14. The apparatus (2) as claimed in claim 4, wherein the first supply unit (13) comprises a first supply lance (13), protruding into the mixing volume defined by the mixing sector (6, M), there being designed on said lance at least one of the at least one first supply opening (35), and/or the second supply unit (15) comprises a second supply lance (15), protruding into the mixing volume defined by the mixing sector (6, M), there being designed on said lance at least one of the at least one second supply opening (35), wherein at least one first and/or at least one second supply opening (35) is or are designed at a distal end, sited within the mixing volume and positioned more particularly approximately centrally to the free cross section of the mixing sector (6, M), of the first and second supply lances (13, 15), respectively, and/or the first and/or second supply openings (34, 35) being designed transversely, to the flow cross section of the mixing sector (6, M) at the location of the respective supply opening, and/or wherein a distance, measured in flow traversal direction (D), between first supply opening (35) and static mixer (14, 17, P) and/or between second supply opening (34, 35) and dynamic mixer (16) is 0.6 to 1.2 times the free diameter (d6) of the mixing sector (6, M) at the location of the first (5) and second mixing units (7), respectively, and/or wherein a distance measured in the flow traversal direction (D) between the first mixing unit (5) and second supply opening (34, 35) is between 0.8 and 1.2 times the free diameter (d.sub.6) of the mixing sector (6, M) at the location of the first mixing unit (5) and/or at the location of the second supply opening (34, 35).

15. The apparatus (2) as claimed in claim 5, wherein the first flocculating agent (F) comprises calcium carbonate (CaCO3) or superficially phosphoric acid (H3PO4)-treated calcium carbonate (CaCO3).

Description

[0053] The invention, including in relation to further features and advantages, is elucidated in more detail below on the basis of an exemplary working example, with reference to the appended drawings. In the drawings:

[0054] FIG. 1 shows an exemplary apparatus of the invention;

[0055] FIG. 2 shows a partial sectional representation of the apparatus;

[0056] FIG. 3 show a construction diagram of one embodiment of the apparatus;

[0057] FIG. 4 shows a sectional representation of the apparatus in the region of the mixing sector;

[0058] FIG. 5 shows a sectional representation of an alternative mixing sector;

[0059] FIG. 6 shows a detail relating to feed lances of the apparatus;

[0060] FIG. 7 shows a schematic representation relating to a detail of a further mixing unit of the apparatus; and

[0061] FIG. 8 shows an exemplary embodiment of a mixing unit according to FIG. 8, comprising an impact plate.

[0062] FIG. 9 shows a sectional representation of a pipeline with installed mixing units;

[0063] FIG. 10 shows a further sectional representation of the pipeline with installed mixing units.

[0064] Parts and components corresponding to one another in FIG. to FIG. 10 are designated with the same reference symbols.

[0065] FIG. 1 shows an exemplary apparatus for flocculating solids fractions of a solid-liquid mixture, and is referred to below for simplification as flocculation apparatus 2. The flocculation apparatus 2 may be mounted or installed, for example, in or on a mobile transport unit, such as a carrying frame or installation frame 11 (see FIG. 2), for example, comprising, for example forklift truck sockets and the like, or a container. By this means, in particular, flocculation apparatus 2 can be transported mobily and flexibly to the respective location of deployment.

[0066] In addition to the flocculation apparatus 2, furthermore, there may be one or more electrical switch cabinets 3, and, additionally, one or more (schematically shown) tanks, preparation units or mixing units 4 for one or more flocculating agents.

[0067] The flocculation apparatus 2 comprises a first mixing unit 5, which is installed on a pipeline 6, this pipeline forming or comprising in particular a mixing sector, and is designed for admixing a first flocculating agent. The first mixing unit 5 may, for example, be adapted and designed for admixing a calcium carbonate (CaCO.sub.3)-based flocculating agent to a solid-liquid mixture, sludge for example, that is flowing through the mixing sector.

[0068] The flocculation apparatus 2 further comprises a second mixing unit 7 which is likewise installed on the mixing sector 6, and is designed for admixing a second flocculating agent. The second mixing unit 7 may be designed, for example, to admix the solid-liquid mixture, flowing through the mixing sector, with a flocculating agent based on a polymer, preferably an acrylamide-free polymer.

[0069] By admixing the first and second flocculating agents it is possible to achieve a coagulation of solids fractions of the solid-liquid mixture, and coagulated solids fractions can subsequently be removed by means, for example, of filtration, centrifugation, or sedimentation.

[0070] The flocculation apparatus 2 of FIG. 1 further comprises an optional flow rate meter 8, which, as in the present case, may be installed at the entry of the mixing sector, and which may be designed to ascertain or measure the quantityfor example, the volume flow or mass flowof the solid-liquid mixture flowing through the mixing sector.

[0071] In the case of the flocculation apparatus 2 shown in FIG. 1, the (optional) flow rate meter 8 is located on the input side of the mixing sector. An output side or outlet opening of the mixing sector is given the reference symbol O. On the input and output sides, the flocculation apparatus 2 may comprise connection interfaces (not shown explicitly) as for example connection flanges, for connecting a conveying line for supplying and/or removing the solid-liquid mixture to and from the mixing sector, respectively.

[0072] In the case of the flocculation apparatus 2 shown in FIG. 1, accordingly, there is a flow traversal direction D indicated by the double arrow. Taking account of the flow traversal direction D, it is found for the working example of FIG. 1 that the first and second mixing units 5, 6 are connected fluidically downstream of the flow rate meter 8. Furthermore, the second mixing unit 7 is connected fluidically downstream of the first mixing unit 5, which is intended to mean that, viewed fluidically, the solid-liquid mixture flowing, or pumped, through the mixing sector passes first through the first mixing unit 5 and then through the second mixing unit 7.

[0073] A first pump unit 9 may be assigned, as shown in FIG. 1, to the first mixing unit 5, with the first pump unit 9 being designed to pump or convey the first flocculating agent via a first supply facility as for example a first supply lance 13, into the mixing sector, i.e., into the volume defined by the mixing sector. A line connection between first pump unit 9 and first supply lance 13 is represented by dashed lines in FIG. 1.

[0074] Correspondingly, a second pump unit 10 may be assigned to the second mixing unit 7, with the second pump unit being designed to pump or convey the second flocculating agent via a second supply facility, as for example a second supply lance 15, into the mixing sector, i.e., into the volume defined by the mixing sector. A line connection between second pump unit 10 and second supply lance 15 is represented with dashed lines in FIG. 1.

[0075] The flocculating agents may be supplied from the tank or from the preparation or mixing unit 4 to the first and/or second pump units via corresponding supply lines, as indicated in FIG. 1 by dashed lines.

[0076] Further details of embodiments of the flocculation apparatus 2 are also described below with reference to FIG. 2, which shows a schematic partial sectional representation of the flocculation apparatus 2.

[0077] The flocculation apparatus 2 may, as shown in FIG. 2, comprise an (optional) installation frame 12, on which components of the flocculation apparatus 2 may be installed, and with which the flocculation apparatus can be mounted in or on a mobile (transport) unit.

[0078] In the representation of FIG. 2 it can be seen that the flow rate meter 8 may be connected via a flange connection to the pipeline 6 defining the mixing sector. Connected fluidically downstream of the flow rate meter 8 may be an (optional) dry matter measurement unit 12, which is adapted and designed to ascertain or to measure the amount of dry matter in the solid-liquid mixture flowing through the mixing sector or in the solid-liquid mixture entering the mixing sector.

[0079] By combination in particular of the measurement values obtained from flow rate meter 8 and dry matter measurement unit 12, relating to quantity and dry content of the solid-liquid mixture supplied, it is possible for the flocculation apparatus 2 to ascertain automatically the quantity of first and second flocculating agents suitable or required in each case for the coagulation of the solids fractions in the solid-liquid mixture.

[0080] The flocculation apparatus 2 may comprise a control unit (see 20 in FIG. 3) which is adapted, and which may be coupled with the first and second mixing units 5, 7 in terms of control technology, in such a way that the respectively required amount of first and second flocculating agents is supplied to the mixing sector. For example, the control unit may be adapted to establish the conveying output of the first and/or second pump units 9, 10 in line with the particular amount of flocculating agents required.

[0081] Connected fluidically in series, in other words one after another, along the mixing sector, i.e., along the pipeline 6, is a first supply lance 13, which protrudes into the volume of the mixing sector defined by the pipeline 6, and a static mixer 14, these components being encompassed by the first mixing unit 5, and also a second supply lance 15, which protrudes into the volume of the mixing sector, and a dynamic mixer 16, these components being encompassed by the second mixing unit 7.

[0082] The supply lances 13, 15 project into the pipeline 6 or into the mixing volume transversely to the flow traversal direction D of the solid-liquid mixture, and supply openings of the supply lances 13, 15 are each disposed at that end of the supply lances 13, 15 that is sited approximately centrally within the pipeline 6. Accordingly, the first and second flocculating agents can be supplied approximately or in the region of the center axis of the flow which forms in the mixing sector, thereby enabling the achievement of comparatively homogeneous admixing and, in complement thereto, a comparatively good coagulation effect.

[0083] The static mixer 14 of the first mixing unit 5 may for example, as shown in FIG. 2, comprise an (optionally two or more) impact plate(s) 17, disposed in the flow volume of the pipeline, this plate or these plates being connected fluidically downstream of the first supply lance 13, more precisely downstream of the outlet opening of the first supply lance 13. By means of the impact plate 17 it is possible for the solid-liquid mixture admixed with the first flocculating agent to be commixed, by virtue of the local change of flow conditions brought about by the impact plate 17, for example. The impact plate 17 may, for example, be adapted such that it breaks up the flow locally and gives rise for example to turbulences, fluidizations, and so on. The use of an impact plate 17, and an accompanying comparatively effective commixing, have proven advantageous especially in the case of supply of a CaCO.sub.3-based flocculating agent to sludges.

[0084] The impact plate 17 may, as shown in FIG. 2, be disposed perpendicularly to the center axis of the mixing volume or of the pipeline 6, more particularly such that its surface normal is aligned parallel to the flow traversal direction D.

[0085] With respect to the cross section of the mixing volume, or of the pipeline, the impact plate 17 may be disposed approximately centrally, and an annular gap may be formed between the inside wall of the pipeline 6 and the outer margin of the impact plate 17 in the case, for example, that pipeline 6 and impact plate 17 have a round cross section.

[0086] The dynamic mixer 16 of the second mixing unit 5 may for example, as shown in FIG. 2, comprise an (optionally two or more) mixing rotor(s) 18, which are motor-driven and protrude transversely to the flow traversal direction into the volume of the mixing sector, any such rotor being connected fluidically downstream of the second supply lance 15, more precisely downstream of the outlet opening of the second supply lance 15.

[0087] The mixing rotor may comprise mixing vanes, which are formed on a drive shaft driven by an electrical drive motor, which extend radially from the drive shaft, and which enable commixing of the solid-liquid mixture, already admixed with the first flocculating agent, with in particular the second flocculating agent. The dynamic mixer 16, or the mixing rotor 18, is more particularly designed to mix the solid-liquid mixture admixed with flocculating agents, so that coagulation of the solids fraction of the solid-liquid mixture is possible or takes place on the basis of the two flocculating agents.

[0088] The impact plate 17 of the static mixer 14 may, as already indicated, be designed, for example, in the manner of a circular disk, in which case, for a diameter, or nominal diameter, d.sub.6 of the mixing sector or of the pipeline 6, respectively, of approximately 250 mm, the outer diameter d.sub.17 of the impact plate 17 may be about 100 mm. Rotor blades of the mixing rotor 18 may be designed, for example, such that the outer diameter d.sub.18 of the rotor 18 is likewise about 100 mm.

[0089] With regard to FIG. 2, a number of other specific dimensions of the flocculation apparatus 2, and mutual spacings of certain components, may be stated. Thus, for example, a distance d.sub.19-8 measured in flow traversal direction D between pipeline inlet 19 and flow rate meter 8 may be in the region of 225 mm, and the distance d.sub.8-12, i.e., center-to-center distance, between flow rate meter 8 and the downstream-sited measurement point of the dry matter unit 12 may be about 393 mm.

[0090] The first supply lance 13, more specifically its outlet opening, may be disposed at a distance d.sub.12-13 of 263 mm, for example, downstream of the measurement point of the dry matter measurement unit 12. The impact plate 17 may be disposed at a distance d.sub.13-17 of about 186 mm from the first supply lance 13, and the second supply lance 15, more precisely its outlet opening, may be disposed at a distance d.sub.17-15 of about 245 mm from the impact plate 17.

[0091] A distance d.sub.15-18 between the second supply lance 15, more precisely its outlet opening, and the mixing rotor 18, more precisely the center axis of the mixing rotor 18, may be about 186 mm.

[0092] For distances between supply opening(s) and mixer(s), reference is made additionally to the observations earlier on above, in which context it shall be mentioned that it is also possible for larger distances to be used between the mixing units, as for example up to 200 times the diameter of the mixing sector, or up to 50 m.

[0093] The stated dimensions and sizings of the components of the flocculation apparatus 2 in particular have proven especially advantageous with regard to coagulation of solids fractions in sludges, especially industrial sludges, as for example waste sludges from copper mines.

[0094] The operation of the apparatus is in particular elucidated further in reference to FIG. 3, which shows a construction diagram of the flocculation apparatus 2.

[0095] As can be seen from FIG. 3, the flocculation apparatus 2 comprises a control unit 20, which is connected in terms of control technology to a first metering pump unit 21 for the first flocculating agent, to a second metering pump unit 22 for the second flocculating agent, and to the dynamic mixer 16. Furthermore, the control unit 20 is connected by control technology to the flow rate meter 8 and to the dry matter measurement unit 12, so that the control unit 20 possesses at least measurement values relating to quantity and dry matter fraction of the solid-liquid mixture conveyed into the pipeline via a feed pump.

[0096] The control unit 20 may, as shown in FIG. 3, be additionally connected by control technology to an (optionally present) facility 23 for producing an acrylamide-free polymer solution. Where such a facility 23 is present, it may also possess an independent control unit, and need not necessarily be coupled by control technology to the control unit 20 of the flocculation apparatus 2.

[0097] The facility 23 for producing the polymer solution may comprise a charging unit 24 for charging a mixing or preparation tank 5 with polymer material, more particularly with pulverulent polymer material, and may comprise a liquid supply facility 26 for supplying a carrier liquid, water for example, for the polymer material. The mixing or preparation tank 25 may comprise one or more mixing chambers each with assigned, motor-driven mixers 27.

[0098] In the operation of the flocculation apparatus 2, the facility 23 for producing the polymer solution may first be operated in such a way that there is sufficient polymer solution of an acrylamide-free polymer available as second flocculating agent.

[0099] For the conditioningdewatering, for exampleof sludge, comprising the coagulation of solids fractions in the sludge, or generally of a solid-liquid mixture, the pipeline 6, comprising the mixing sector, has the solid-liquid mixture conveyed to it and conveyed through the mixing sector, via a conveying pump 28, which is fluidically connected to the pipeline inlet 19 of the pipeline 6.

[0100] By means of the flow rate meter 8 and of the dry matter unit 12, quantity and dry matter of the mixture supplied are ascertained, and the values thus ascertained are supplied to the control facility 20, which ascertains required or optimum amounts of first and second flocculating agents, respectively.

[0101] In the present example, the flocculation apparatus 2 may be designed to supply a CaCO.sub.3-based first flocculating agent via the first metering pump unit 21 to the mixing sector via the first supply lance 13, this flocculating agent being combined with the solid-liquid mixture by means of the impact plate 17 of the static mixer.

[0102] Via the second metering pump unit 22, which is controlled correspondingly by the control unit 20 with regard to the amount of second flocculating agent metered in, an acrylamide-free polymer solution is supplied as second flocculating agent, by the second supply lance 15, to the solid-liquid mixture already combined with the first flocculating agent. The second flocculating agent is combined with the solid-liquid mixture by means of the dynamic mixer 16.

[0103] Following passage through the dynamic mixer, the solid-liquid mixture with admixed flocculating agents reaches the outlet opening O of the mixing sector, or of the pipeline, and can be supplied, for example, to a filter unit (not shown) connected fluidically downstream, for the purpose of removal of coagulated solids fractions.

[0104] FIG. 4 shows a sectional representation of the apparatus 2 in the region of the mixing sector M, defined by the pipeline 6, or in a corresponding mixing volume. Merely for the sake of completeness it may be stated that the pipeline is installed and supported on support feet which can be screwed to a base.

[0105] The pipeline 6 may, as shown in FIG. 4, two connection couplings 37, connected fluidically in series in the flow traversal direction and sited, for example, on the same side of the pipeline 6, these connection couplings comprising, for example, a flange connection in each case, for the purpose of connecting the first 5 and second 6 mixing units, particularly in a fluid-tight manner. The connection couplings 37 may be used for example in a disposition sited to the side in operation of the apparatus 1.

[0106] Sited upstream of the connection couplings 37 in terms of the flow traversal direction D it is possible, as shown in FIG. 4, for insertion openings 38.1 and 38.2, or engagement openings, for the first 13 and second 15 supply lances, respectively, to be provided in the walls of the pipeline. The insertion openings 38, or more precisely their center points, may lie, for example, on a line which runs in the longitudinal direction of the pipeline 6; in other words, the insertion openings 38 may be disposed flush one after another as viewed in the flow traversal direction. As can be seen in FIG. 4, the pipeline may be disposed, in operation of the apparatus, in such a way that the engagement openings 38 are disposed below the level of the passage openings 39 present in the region of the connection couplings 37, more particularly on the same side as the connection couplings 37, in the pipeline 6.

[0107] FIG. 5 shows a sectional representation of an alternative mixing sector M, or an alternative pipeline geometry of the pipeline 6. The pipeline 6 of the exemplary embodiment in FIG. 5 is tapered toward both ends of the mixing sector M, or at both ends of the pipeline 6.

[0108] Expressed in other words, the pipeline 6 is widened radially in relation to the longitudinal axis, with the widening as viewed in the longitudinal direction of the pipeline 6, or parallel to the flow traversal direction D, being selected such that at least the passage openings 39 and the insertion openings 38 are included. By means of widening it is possible in certain circumstances to achieve improved commixing, and/or the mixing sector M can be modified for the particular solid-liquid mixture to be treated, this modification being in relation to geometry, disposition and position of the first mixing unit 5 and second mixing unit 7.

[0109] The second mixing unit 7 may comprise a rotor unit 30, connected to the pipeline 6 via a flange connection 29, this unit having a drive shaft 31 and having a mixing rotor unit 32 mounted at the distal end of the drive shaft 31. The rotor body of the mixing rotor unit 32 has a cylindrical design in the present example, and on opposite longitudinal sides has a respective mixing vane 33, as can be seen from FIG. 9, for example. The mixing rotor unit 32, more particularly the mixing vanes 33, in operation of the flocculation apparatus 2, produce mixing of the second flocculating agent F2 with a solid-liquid mixture flowing past at the second mixing unit 7.

[0110] As can be seen, for example, from FIG. 1 and FIG. 9, the second flocculating agent F2 may be supplied via a nozzle or lance 15 and the like that is connected fluidically upstream, for example, of the mixing rotor unit 32, being therefore disposed upstream.

[0111] One example of a corresponding nozzle or lance arrangement is shown in FIG. 6. Specifically, FIG. 6 shows a cross section of the pipeline 6 in the region, for example, of the first or second supply lance 13 or 15. In the example of FIG. 6, the supply lance 13 or 15 has a lance outlet opening 35 positioned obliquely to the flow or flow direction or flow traversal direction D, and the respective flocculating agent F, whether it is the first flocculating agent or the second flocculating agent F2, can be supplied via said opening 35.

[0112] In the present example, specifically, the lance outlet opening 35 is adapted and aligned in such a way that an angle of approximately 45 degrees is formed between the flow traversal direction D and the opening plane E of the lance outlet opening 35, measured counterclockwise in the direction of rotation. The angle selected may also be different, according to the properties of the flocculating agent F and/or of the solid-liquid mixture to be treated. Furthermore, the lance outlet opening 35 may have a different attitudinal position to the flow, and/or the opening plane E of the lance outlet opening 35 may have a different orientation relative to the flow traversal direction D or to the pipeline 6.

[0113] FIG. 7 shows a further detail of the flocculation apparatus or of a flocculation apparatus 2 of the invention, in the region of the static mixer 14. Specifically, the static mixer 14 of FIG. 7 is designed in the form of an impact unit, comprising an impact plate 17 fastened in the pipeline 6.

[0114] In the example of FIG. 7, the impact plate 17 has a round design, meaning that the impact plate 17 has a round impact surface P. The geometry of the impact surface P and of the impact plate 17 are selected in the present example such that, between the inside walls of the pipeline 6 and the outer margin of the impact surface P or impact plate 17, an annular gap 36 is formed, having a gap width which is approximately constant as viewed in the radial direction with respect to the pipeline 6. It may be noted that the orientation, position and/or geometry and/or shape of the impact plate may also be differently designed, depending, for example, on the properties of the particular solid-liquid mixture to be treated, more particularly sludge.

[0115] In the case of a pipeline diameter of 25 cm, for example, the diameter of the impact plate 17 may be 10 cm, for example, thus forming an annular gap having a width of about 75 mm between the inside walls of the pipeline 6 and the outer margin of the impact plate 17. Such geometries are suitable in particular for the mixing of flocculating agents with sludgeswith regard to the sludges, reference is made in particular to the examples referred to earlier on above.

[0116] The effect of the impact plate 17 disposed in the volume of the pipeline 6, or of the impact unit, is that there is an increase in the flow rate in the region of the impact unit or impact plate 17 in the pipeline 6, and so in the region of the impact plate 17, more particularly downstream of the impact plate 17, given a suitable flow rate, it is possible for flow turbulences and associated fluidizations to develop, which effect, evoke and/or promote the mixing of the first flocculating agent with the solid-liquid mixture.

[0117] FIG. 8 shows a specific working example of the static mixer 14. As shown in FIG. 8, the static mixer 14 may have a flange plate 40, which can be joined to the corresponding connection coupling 37, more particularly to the corresponding connection flange, and in this flange plate 40 there may be, for example, drilled holes around the marginal side for the purpose of screw fastening of the flange plate 40 to the connection coupling 37.1.

[0118] On the flange plate 40, as for example in a central region or a region adjacent to the center, there may be a fastening arm 41 which projects from the flange plate 40 and is fastened to the flange plate 40. At an end remote from the flange plate 40, the fastening arm 41 may be connected to a or the impact plate 17, or the impact plate 17 may be mounted there. The length of the fastening arm 41 is selected such that in the installed state of the flange plate 40 on the connection coupling 37.1, the impact plate is positioned approximately centrally in the pipeline 6. The drilled holes made in the flange plate 40 may be adapted such as to enable a form of fastening wherein the impact plate 17, i.e. the impact surface P, is disposed substantially perpendicularly to the flow traversal direction D, or such that a corresponding angle of inclination exists between impact surface P and flow traversal direction D.

[0119] FIG. 9 shows a sectional representation of the pipeline 6 with installed mixing units 5, 7, where the first mixing unit 5, comprising the static mixer 14, is installed on the respective connection coupling 37.1, so that the impact plate 17 is disposed in a perpendicular orientation to the flow traversal direction D in the mixing sector M and is disposed fluidically downstream of the first supply lance 13. FIG. 10 shows a further sectional representation of the pipeline 6 with installed mixing units 5, 7 as viewed in the direction of the flow traversal direction D.

[0120] The second mixing unit 7, comprising a dynamic mixer 16 with rotor unit 30 comprising drive motor, is installed via a flange connection on the other connection coupling 37.2. In the present example, the rotor unit 30 is disposed fluidically downstream of the second supply lance 15, meaning that the respective second flocculating agent is supplied via the second supply lance 15 to the mixing rotor unit 32.

[0121] The extent to which the supply lances 13, 15 are introduced into the pipeline 6 may for example be such that in operation of the apparatus 1, the respective flocculating agents can be introduced approximately centrally, with respect to the pipe cross section or the cross section of the mixing sector M, into the solid-liquid mixture flowing through the mixing sector M. As a result of the development of flow eddies due to the impact plate 17, it is possible, in the fluidically downstream volume, to achieve commixing of the solid-liquid mixture with the first flocculating agent. With a suitable fluidic distance between impact plate 17 and second supply lance 15, furthermore, it is also possible, for example, at least to promote the introduction of the second flocculating agent, there being active commixing of the solid-liquid mixture with the two added flocculating agents by means in particular of the downstream active mixer 7.

[0122] The described operation of the flocculation apparatus with two-stage admixing of a first and a second flocculating agent, and with the use of different types of mixer for the first flocculating agent, based for example on CaCO.sub.3, and for the second flocculating agent, based for example on an acrylamide-free polymer, is suitable particularly for the conditioning of sludges, as for example spoil sludges from copper mines.

[0123] Through the possibility of the metering of the flocculating agents by the first and second mixing units and through the two-stage, successive supply of the flocculating agents, in particular, it is possible to achieve a comparatively good coagulation outcome with comparatively good solid-liquid separation.