APPARATUS FOR MEMBRANE FILTRATION AND FOR REMOVAL OF MICROPOLLUTANTS FROM LIQUIDS BY MEANS OF A REACTIVE SUBSTANCE

Abstract

The invention relates to a device for membrane filtration and for the removal of micropollutants from liquids by way of a reactive substance, the device comprising a reaction chamber and at least one port for supplying and/or discharging the reactive substance to and/or from the reaction chamber, such that the micropollutants are able to react with the reactive substance in the reaction chamber and/or may be removed from a liquid, and the reaction chamber comprising a first membrane and a second membrane, the first membrane being designed as an inlet into the reaction chamber and the second membrane being designed as an outlet from the reaction chamber, such that the liquid to be treated is able to be filtered by the first membrane and to flow into the reaction chamber, the liquid treated with the reactive substance in the reaction chamber is able to be filtered by the second membrane and to flow out of the reaction chamber, and the outflow of treated liquid is substantially free from micropollutants.

Claims

1. A device (101, 201, 301, 401, 501, 601) for membrane filtration and for the removal of micropollutants (119) from liquids by way of a reactive substance (115), the device comprising a reaction chamber (103, 203, 303, 403) and at least one port for supplying and/or discharging the reactive substance to and/or from the reaction chamber, such that the micropollutants are able to react with the reactive substance in the reaction chamber and/or may be removed from a liquid, and the reaction chamber comprising a first membrane (105, 205, 305, 405, 505, 605) and a second membrane (107, 207, 307, 407, 507, 607), wherein the first membrane (105, 205, 305, 405, 505, 605) is designed as an inlet into the reaction chamber and the second membrane (107, 207, 307, 407, 507, 607) is designed as an outlet from the reaction chamber, such that the liquid to be treated is able to be filtered by the first membrane and to flow into the reaction chamber (103, 203, 303, 403), the liquid treated with the reactive substance in the reaction chamber is able to be filtered by the second membrane and to flow out of the reaction chamber, and the outflow of treated liquid is substantially free from micropollutants.

2. The device as claimed in claim 1, wherein the second membrane has a smaller pore size than the first membrane, such that the reactive substance may be retained in the reaction chamber.

3. The device as claimed in claim 1, wherein the first membrane is arranged on one side of the reaction chamber and the second membrane is arranged on a side of the reaction chamber opposite that side.

4. The device as claimed in claim 1, wherein the device is set up in such a way that a flow direction (117, 217, 317) of the reactive substance is substantially at right angles to an inflow and/or outflow direction of the liquid through the first and/or second membrane.

5. The device as claimed in claim 1, wherein the first membrane and/or the second membrane is or are a submerged membrane.

6. The device as claimed in claim 1, wherein the first membrane and/or the second membrane is or are a microfiltration membrane, an ultrafiltration membrane (205, 207, 305, 405, 505, 605) and/or a nanofiltration membrane (307, 407, 507, 607).

7. The device as claimed in claim 1, wherein the reaction chamber is designed and/or is operable as a batch reactor and/or as a continuous-flow reactor.

8. The device as claimed in claim 1, wherein the device has a regeneration unit for regenerating consumed reactive substance or a regeneration unit is associated with the device.

9. The device as claimed in claim 1, wherein the device contains a reactive substance or a plurality of reactive substances, wherein the reactive substance or plurality of reactive substances is or are a dissolved, emulsified, dispersed, suspended and/or solid substance.

10. The device as claimed in claim 9, wherein the reactive substance or the reactive substances is or are an oxidant, absorbent, precipitant, coagulant, flocculant, ion exchanger, catalyst and/or biogenic sub stance.

11. The device as claimed in claim 5, wherein the submerged membrane is a flat-sheet membrane, a spiral-wound membrane, and/or a pressurized tubular membrane.

Description

[0061] A membrane-reactive device 101 has a coarse-pore UF membrane 105 and a fine-pore UF membrane 107. A reaction chamber 103 is formed between the coarse-pore UF membrane 105 and the fine-pore UF membrane 107. An untreated liquid stream 109 containing micropollutants 119 enters the reaction chamber 103 through the coarse-pore UF membrane 105 at a differential pressure of approximately 1 bar transmembrane pressure, particulate substances (not shown) being held back by the coarse-pore UF membrane 105 such that a prefiltered untreated liquid 111 is present in the reaction chamber 103. A pore size of the coarse-pore UF membrane 105 is chosen such that the micropollutants 119, which are inter alia pharmaceutical residues, pass through the coarse-pore UF membrane 105 and enter the reaction chamber 103 (see FIG. 1).

[0062] Oriented at right angles to the untreated liquid stream 109 is a flow direction 117 of reactive substances 115 which were introduced into the reaction chamber 103 via a port not shown in FIG. 1 and are circulated through the reaction chamber 103 in the flow direction 117 by a pump (not shown). The reactive substances 115 are ultra-fine powdered activated carbon particles on which the micropollutants 119 are adsorbed. The continuous untreated liquid stream 109 causes the treated liquid in the reaction chamber 103 at a pressure of approximately 6 bar transmembrane pressure across the fine-pore UF membrane 107 to be continuously pushed through this fine-pore UF membrane 107 and thus to be filtered more finely, such that a filtrate stream 113 emerges from the fine-pore UV membrane 107. Owing to the oppositely arranged coarse-pore UF membrane 105 and fine-pore UF membrane 107 of the reaction chamber 103, the untreated liquid stream 109 and the filtrate stream 113 are oriented in the same direction, while the flow direction 117 of the reactive substances 115 is oriented at right angles to the untreated water stream 109 and the filtrate stream 113.

[0063] In one of a number of possible embodiments, a membrane-reactive device 201 is designed as a double-membrane structure. Here, a fine-pore UF membrane 207 in tubular form, from both ends of which a permeate stream 213 emerges from a second drain 227 (permeate chamber), is surrounded by a flat coarse-pore UF membrane 205. The reaction chamber is embodied as a first drain 203 between the coarse-pore UF membrane 205 and the fine-pore UF membrane 207. The untreated liquid 211 prefiltered by the coarse-pore UF membrane 205 is circulated through the double-sided first drain 203 (reaction chamber) in accordance with a flow direction 217 of the reactive substances. FIG. 2 shows only a detail of the membrane-reactive device 201, so the circulatory connection for the flow through the double-sided first drain 203 is not shown in FIG. 2.

[0064] A feed chamber 221 having a first agitator 223 and a second agitator 225 is arranged on an untreated liquid side of the coarse-pore UF membrane 205. The first agitator 223 and the second agitator 225 cause untreated water in the feed chamber 221 to flow from outside in an optimal manner to the coarse-pore UF membrane 205, and particles retained in the feed chamber 221 by the coarse-pore UF membrane 205 are prevented from accumulating in front of the coarse-pore UF membrane 205 and leading to an undesired cake formation by the particles. The untreated liquid 211 prefiltered by the coarse-pore UF membrane 205 enters the first drain 203 (reaction chamber) where it comes into contact with the reactive substances (not shown), the ultra-fine powdered activated carbon particles as reactive substances reacting with the micropollutants contained in the prefiltered untreated liquid. The reactive substances loaded with the micropollutants are circulated through the first drain 203 in accordance with the flow direction 217 of the reactive substances. A transmembrane pressure of approximately 6 bar across the fine-pore UF membrane 207 causes the prefiltered untreated liquid 211 in the first drain 203 to pass through this fine-pore UF membrane 207 into the second drain 227 (permeate chamber), and it leaves the second drain 227 from both ends as a permeate stream 213. The fine-pore UF membrane 207 has a pore size corresponding to 15 kDa, so the ultra-fine powdered activated carbon particles as reactive substances are unable to pass through the fine-pore UF membrane 207 but instead remain in the first drain 203 and hence in circulation.

[0065] The membrane-reactive device 201 thus provides a double-membrane system having different pore sizes and dual filtration, with an integrated, intermediate reaction chamber for the removal of micropollutants by way of reactive substances. Thus, both a two-stage filtration and a further purification to remove micropollutants are achieved in a single treatment stage.

[0066] In one alternative, the membrane-reactive device is designed as a membrane-reactive modular tubular reactor 301. The inside of the membrane-reactive modular tubular reactor 301 comprises a plurality of tubular membranes 306 (three tubular membranes 306 are shown purely schematically in FIG. 3). Inside each tubular membrane 306 is a tube 302 with a surrounding UF membrane 305. The UF membrane 305 is surrounded by a UF drain 303, which forms the reaction chamber. The UF drain 303 is in turn surrounded by the NF membrane 307, which is closed off from the NF drain 327 on the outside. Thus, untreated water flows through each tubular membrane 306 from the inside to the outside.

[0067] In the upper part of the membrane-reactive modular tubular reactor 301, the tubes 302 are cast in a cast plane 335 of the UF. Similarly, a second, lower cast plane 335 surrounds the tubes 302 in the lower part of the membrane-reactive modular tubular reactor 301. In this way, an untreated liquid stream is only able to flow through the interior of the respective tube 302 via a surrounding feed intake 309 at the top of the membrane-reactive modular tubular reactor 301 since a surrounding wall of the membrane-reactive modular tubular reactor 301 together with the cast plane 335 of the UF form a feed chamber 321 on the inside. The untreated liquid passes from inside out of the tubes 302 through the surrounding UF membrane 305 and as a prefiltered untreated liquid 311 thus enters a chamber which is formed by the lower side of the cast plane 335 of the UF and the upper side of an upper cast plane 337 of the NF, and in the UF drain 303 it comes into contact with the reactive substances which are pumped into the membrane-reactive modular tubular reactor 301 via the inflow 331. Owing to the upper cast plane 337 of the NF, the mixture consisting of prefiltered untreated liquid 311 and the reactive substances is only able to flow in a flow direction 317 in a longitudinal direction of the UF drain 303, undergoing a reaction in the process. The reactive substances are held back by the NF membrane 307 and leave a chamber that is formed between a lower side of the lower cast plane 335 of the UF and an upper side of a lower cast plane 337 of the NF via a reactive substance outflow 333 in the membrane-reactive modular tubular reactor 301.

[0068] On the lower side, after the lower cast plane 335 of the UF, the untreated liquid leaves the membrane-reactive modular tubular reactor 301 via a feed outflow 310. The prefiltered untreated liquid 311 is filtered further by the NF membrane 307 and a permeate that is formed passes through the NF drain 327 into the permeate chamber 329 between the upper and lower cast plane 337 of the NF and is discharged via a permeate flow 313.

[0069] In a further alternative, the membrane-reactive device is designed as a membrane-reactive parallel flat-sheet module 401 (FIG. 5 shows two parallel flat-sheet modules one on top of the other). In this case, an NF drain 427 on the inside is surrounded by an NF membrane 407 and the NF membrane 407 is in turn surrounded by a UF drain 403 as the reaction chamber and on the outside by the UF membrane 405, forming a flat-sheet module through which untreated liquid flows from the outside to the inside. The ends of the NF membrane 407 are cast in a cast plane 437 of the NF and the respective NF drain 427 is connected to a permeate outflow 413. On the opposite side, the UF drain 403 is connected to a reactive substance inflow 431 and the ends of the UF membrane 405 are cast in a cast plane 435 of the UF. The individual flat-sheet modules are separated by spacers 441, flow channels for the feed inflow and outflow being formed between the spacers 441.

[0070] The membrane-reactive parallel flat-sheet module 401 is surrounded by a cast ring 439 (see FIG. 6) in which a feed intake 409 and a feed outflow 410 are embedded. The inflow 431 of the reactive substances takes place at the end via tubes leading into the UF drain 405 and the outflow 433 of the reactive substances likewise takes place at the end in the region of the cast plane 435 on the basis of an appropriate flow control along the respective flat-sheet membrane. At the opposite end, in the region of the cast plane 437 of the NF, a plurality of tubes for the permeate outflow 413 are arranged. The membrane filtration by way of the UF membrane 405, the reaction with the reactive substances in the UF drain 403 and the additional fine filtration by way of the NF membrane 407 take place in the same way as described above.

[0071] In a further alternative, the membrane-reactive device is designed as a membrane-reactive pressurized tube (spiral-wound module) 501. The membrane-reactive pressurized tube 501 has a perforated central tube 545 in the middle. Each NF membrane 507 is designed as a membrane envelope supported by an inner permeate spacer 543, each permeate spacer 543 being fluidically connected to the perforated central tube 545. Each UF membrane 505 is likewise designed as a membrane envelope with an inner feed spacer 541, and they are arranged evenly around but not in contact with the central tube 545. The flow through each UF membrane 505 is from the inside to the outside. A reaction chamber spacer 547 is arranged on each side of each UF membrane 505 (see FIG. 7). The envelopes of the UF membranes 505 are cast at both ends in an upper cast plane 535 and a lower cast plane 537, and they pass through the upper cast plane 535 up to the feed intake 509 and down to the feed outflow 510, the envelopes of the UF membranes 505 being open at these two ends. The envelopes of the NF membranes 507 are sealed all round and are fixed at the ends in the upper cast plane 535 and the lower cast plane 537 (see FIG. 8).

[0072] The untreated water enters the membrane-reactive pressurized tube 501 via a feed intake 509, flows through the respective feed spacers 541 and is prefiltered by UF membranes 505. In a chamber between the upper cast plane 535 and the lower cast plane 537, the prefiltered untreated water 511 comes into contact with the reactive substances which are supplied to the membrane-reactive pressurized tube 501 via the inflow 531 and leave it again via the outflow 533. The reactive substances are held back as described above by the NF membranes 507, while the permeate passes through the NF membranes 507 and flows through the permeate spacers 543 into the perforated central tube 545, from where the permeate leaves the membrane-reactive pressurized tube 501 via the permeate flow 513 on either side of the central tube 545. The two-stage filtration and the reaction with the reactive substances take place in the same way as described above.

[0073] In a further alternative of the membrane-reactive pressurized tube 601 in the form of a spiral-wound module, each NF membrane 607 in the form of a membrane envelope with inner permeate spacers 643 is likewise arranged directly at a perforated central tube 645. In this case, however, the membrane envelope of the NF membrane 607 is completely enclosed by a UF membrane 605 with reaction chamber spacers 647 interposed therebetween (FIG. 9). The membrane envelopes of the outer UF membranes 605 are separated from one another by feed spacers 641 arranged between them.

[0074] The UF membrane 605 together with the reaction chamber spacers 647 passes through both an upper cast plane 635 and a lower cast plane 537 (FIG. 10). Correspondingly, the UF membrane 605 is open at these ends above the upper cast plane 635 and below the lower cast plane 637, such that reactive substances flow through the inflow 631 into the inner chamber between UF membrane 605 and NF membrane 607 supported by the reaction chamber spacer 647 and flow out of the membrane-reactive pressurized tube 601 via an outflow 633 for the reactive substances. The membrane envelopes of each NF membrane 607, which are closed on all sides, are cast in the upper cast plane 635 and the lower cast plane 637 and are thus fixed in place.

[0075] In this embodiment, the untreated water containing micropollutants enters the membrane-reactive pressurized tube 601 from the side via a feed intake 609 and meets the outer side of the UF membrane 605. The flow through each UF membrane 605 is thus from the outside to the inside, and the prefiltered untreated water is contained in the chamber between the UF membrane 605 and the NF membrane 607 supported by the reaction chamber spacers 647, to which chamber the reactive substances are supplied as described above. From this chamber between the UF membrane 605 and the NF membrane 607, the permeate passes through the inner NF membrane 607 and is discharged via the permeate spacers 634 to the perforated central tube 645 and through both ends thereof to the permeate flow 613, while the reactive substances loaded with micropollutants leave the membrane-reactive pressurized tube 601 via the outflow 633. The two-stage filtration and the reaction with the reactive substances take place here in the same way as described above.

LIST OF REFERENCE CHARACTERS

[0076] 101 Membrane-reactive device [0077] 103 Reaction chamber [0078] 105 Coarse-pore UF membrane [0079] 107 Fine-pore UF membrane [0080] 109 Untreated liquid stream [0081] 111 Prefiltered untreated water [0082] 113 Filtrate stream [0083] 115 Reactive substances [0084] 117 Flow direction of reactive substances [0085] 119 Micropollutants [0086] 201 Membrane-reactive device [0087] 203 First drain (reaction chamber) [0088] 205 Coarse-pore UF membrane [0089] 207 Fine-pore UF membrane [0090] 211 Prefiltered untreated liquid [0091] 213 Permeate stream [0092] 217 Flow direction of reactive substances [0093] 221 Feed chamber [0094] 223 First agitator [0095] 225 Second agitator [0096] 227 Second drain (permeate chamber) [0097] 301 Membrane-reactive modular tubular reactor [0098] 302 Tube [0099] 303 UF drain (reaction chamber) [0100] 305 UF membrane [0101] 307 NF membrane [0102] 306 Tubular membrane [0103] 309 Feed intake (untreated water stream) [0104] 310 Feed outflow [0105] 311 Prefiltered untreated liquid [0106] 313 Permeate outflow [0107] 317 Flow direction of reactive substances [0108] 321 Feed chamber [0109] 327 NF drain [0110] 329 Permeate chamber [0111] 331 Inflow of reactive substances [0112] 333 Outflow of reactive substances [0113] 335 UF cast plane [0114] 337 NF cast plane [0115] 401 Membrane-reactive parallel flat-sheet module [0116] 403 UF drain (reaction chamber) [0117] 405 UF membrane [0118] 407 NF membrane [0119] 409 Feed intake (untreated water stream) [0120] 410 Feed outflow [0121] 413 Permeate outflow [0122] 427 NF drain [0123] 431 Inflow of reactive substances [0124] 433 Outflow of reactive substances [0125] 435 UF cast plane [0126] 437 NF cast plane [0127] 439 Cast ring [0128] 441 Spacer [0129] 501 Membrane-reactive pressurized tube [0130] 505 UF membrane [0131] 507 NF membrane [0132] 509 Feed intake (untreated water stream) [0133] 510 Feed outflow [0134] 511 Prefiltered untreated water [0135] 513 Permeate outflow [0136] 531 Inflow of reactive substances [0137] 533 Outflow of reactive substances [0138] 535 Cast plane [0139] 537 Cast plane [0140] 541 Feed spacer [0141] 543 Permeate spacer [0142] 545 Central tube [0143] 547 Reaction chamber spacer [0144] 601 Membrane-reactive pressurized tube [0145] 605 UF membrane [0146] 607 NF membrane [0147] 609 Feed intake (untreated water stream) [0148] 610 Feed outflow [0149] 613 Permeate outflow [0150] 631 Inflow of reactive substances [0151] 633 Outflow of reactive substances [0152] 635 Cast plane [0153] 637 Cast plane [0154] 641 Feed spacer [0155] 643 Permeate spacer [0156] 645 Central tube [0157] 647 Reaction chamber spacer