WO2024003696A1

WO2024003696A1 - Apparatus and method for treating water

Info

Publication number: WO2024003696A1
Application number: PCT/IB2023/056565
Authority: WO
Inventors: Michael Kühlwein
Original assignee: TEC Austria GmbH
Priority date: 2022-06-27
Filing date: 2023-06-26
Publication date: 2024-01-04
Also published as: DE102022115962A1

Abstract

Disclosed is an apparatus (2) for treating water, comprising: - an inlet (4) for supplying the water to be treated, - a sedimentation device (6) downstream of the inlet (4) for sedimentation of suspended solids out of the water to be treated, wherein the sedimentation device (6) comprises at least - an enrichment path (8) for enriching the water to be treated with a coagulant (10) and - a regulation path (18), downstream of the enrichment path (8), for introducing a regulation means (22) that adjusts the pH of the water to be treated, and - a filter device (28), downstream of the sedimentation device (6), having a filter medium (30) which is mounted, in a direction at an angle to the direction of flow of the water to be treated through the filter device (28), so as to be movably driven, and - a reverse-osmosis device (40), downstream of the filter device (28), for advanced cleaning of the water to be treated.

Description

Device and method for treating water

Description

The present invention relates to a device and a method for treating water.

In a multi-stage water treatment, a sedimentation device can enable both the reduction and/or removal of hardness formers, in particular calcium ions, and also lead to a reduction in TOC (total organic carbon) in drinking water. Although this two-stage procedure is known, it is not the standard procedure for water treatment and is usually contradictory, since the TOC reduction is typically achieved at a low pH value between 4.0-7.3 and the reduction in hardness formers is typically achieved at higher pH values. Values between 9.5-11.5 can be achieved. The presence of TOCs also acts as an inhibitor in the precipitation of calcium.

When carrying out this special process, extensive subsequent steps are typically required, which makes the dimensioning of the system almost unsuitable for the use of 50 PE (population values) to 1000 PE. Such information is used, among other things Specification of small sewage treatment plants, used in accordance with DIN EN 12566 (Al version from 2003) and DWA-A 222.

Grease separators and/or small sewage treatment plants are typically used to treat household wastewater, which deliver satisfactory results for this type of wastewater.

The situation is different in the field of system catering, in which the dirt load per cubic meter of water is significantly higher than with conventional household wastewater. This is where small sewage treatment plants and/or grease separators reach their limits. At the same time, wastewater disposal facilities or sewer operators have specifications for a maximum dirt load for this type of wastewater.

Water treatment systems for this area of application are hardly known, especially in the system catering application, the focus is on problems such as a small installation space requirement and a small number of maintenance cycles, which have so far only been inadequately solved by large-scale systems.

Based on this preliminary consideration, the object of the present invention is to provide a system for water treatment for wastewater with a high dirt load, which is characterized by a compact structure and almost maintenance-free operation with the highest possible cleaning efficiency.

The task is solved by the features of the independent claims. Preferred further developments are the subject of the dependent claims.

According to one aspect of the invention, a device according to the invention for treating water comprises:

- an inlet for supplying the water to be treated,

- a sedimentation device adjoining the inlet for sedimentation of suspended matter from the water to be treated, the sedimentation device being at least -an enrichment path for enriching the water to be treated with a coagulant and

-a regulating path adjoining the enrichment path for introducing a regulating agent which adjusts the pH value of the water, and a filter device adjoining the sedimentation device with a filter medium which is mounted in a movably driven manner in a direction at an angle to the flow direction of the water to be treated through the filter device is and

- A reverse osmosis device connected to the filter device for further filtering of the water.

The sedimentation device is already characterized by a high degree of cleaning, as it achieves the reduction of hardness formers, such as calcium compounds, by adding the regulating agent on the one hand and, at the same time, a reduction in the TOC content by adding the coagulant in a single device. The sedimentation is supported by the compaction of the flakes formed through the formation of a hydroxide species. The specific density of the flakes formed by the coagulant changes.

The regulation path can be followed by a flocculation path, in which precipitation is initiated after the addition of the regulation agent, typically a base, in particular a sodium hydroxide solution. In particular, an inclined lamella clarifier can be used as a sedimentation system.

The sedimentation system can optionally be supplemented by a gas inlet to mix the regulating agent and the coagulant with the wastewater. However, a conventional slat clarifier can also be used for sedimentation without gas introduction.

The slats enable a more defined subdivision of the respective paths within a housing

Sedimentation device into different sections and enlarge at the same time the efficient clarifying area for sedimentation after precipitation.

Despite sedimentation, suspended matter or other finely divided solids may still be present within the water when it leaves the sedimentation device. On the one hand, these can be particles that are not bound by the coagulant or smaller solid particles formed by the coagulant and regulating agent that have not yet agglomerated into larger units.

At this point, the specified device has a filter device with a movably mounted filter medium. The movement of the filter medium takes place in a direction at an angle to the flow direction of the water to be treated through the filter device. The expert knows this as dynamic cross-flow filtration, or DCF for short, in which the filter medium is moved relative to the water to be treated. If the filter medium rotates around an axis of rotation, this is referred to as rotation-dynamic cross-flow filtration. Using this form of cross-flow filtration allows for the efficient removal of large numbers of particles from the water. At the same time, it is compact and can be operated in a self-cleaning and therefore almost maintenance-free manner, in particular thanks to a return impulse device.

It has surprisingly been shown that the arrangement of this filter device between the sedimentation device and a downstream reverse osmosis device prevents the reverse osmosis device from blocking, which would otherwise lead to short maintenance intervals for the system due to the particle content of the water downstream of the sedimentation device.

Dynamic cross-flow filtration is also characterized by its compact overall structure, which is an advantage for the application area mentioned at the beginning with low population values, for example in fast food restaurants and the like.

The reverse osmosis device enables both further Removal of fine particles as well as a reduction in salt content.

The specified device is thus set up to carry out a multi-stage chemical/physical process for the treatment of wastewater from system gastonomy or, in other words, kitchen wastewater with a high dirt load. The treated water, which is provided by the specified device, can be used as process water.

Usual large-scale devices using biological stages are preferably not used in the present process due to their large space requirements and the process-related risks.

The specified device is designed in particular for the catering industry or in a catering establishment, in particular system catering, such as fast food restaurants or so-called QS restaurants (quick service restaurants).

The filter device in the specified device can have a container and a filter element arranged therein, the filter element having a hollow shaft and one or more filter disks arranged coaxially on the hollow shaft. The one filter disk or the several filter disks preferably have the filter medium and/or consist of it. It is possible for several filter plates to be assembled on a frame to form the filter disk. The filter plates can, for example, have a circular sector-shaped filter surface. In this case, the frame can be made of a different material than the filter plates. However, it is also possible for a corresponding filter disk to be formed uniformly from the filter medium.

The filter element or at least the filter disks can be rotatably mounted in the container. This makes it possible for the filter disks to be rotatably mounted around the hollow shaft. In an alternative In a preferred variant, the filter disks are firmly connected to the hollow shaft and this in turn is rotatably mounted in the container. The entire filter element is therefore rotatably mounted. The second variant is structurally simpler to implement.

The filter disks preferably have a fluid drainage area in their interior, which opens into the hollow shaft, such that the drainage of a filtrate from the filter device takes place along the longitudinal axis of the hollow shaft.

The filter medium can advantageously have an average porosity over the filter medium surface between 5 to 200 nm, in particular between 30 to 100 nm. Particles above this size would clog the membrane of the downstream reverse osmosis device after just a short period of operation so that cleaning would be necessary.

The filter medium of the filter device of the specified device can preferably be formed from a ceramic material, preferably from aluminum oxide and/or zirconium oxide. Such a material is particularly suitable for long operating times and is comparatively robust against mechanical damage.

The filter device of the specified device can have a return pulse system for self-cleaning. This can preferably be a counter-pressure generator and particularly preferably a piston lifting device. The return pulse system can preferably be arranged along a filtrate discharge line of the filter device, so that the return pulse is introduced from the clean side of the filter medium and the pulse on the raw side of the filter medium causes deposits to be loosened.

The filter device can, in particular on the clean side, have one or more sensors for monitoring the filter efficiency, preferably a flow measuring device for measuring flow and/or a turbidity sensor for measuring the solids content of the filtered Water. Instead of the turbidity sensor, other sensors, for example a viscosity measuring device, can also be used for the stated purpose of measuring the solids content. A control and/or evaluation unit can adjust the movement speed of the filter medium, in particular the rotation speed of the filter disks, and/or the inlet volume of water to be cleaned or the medium pressure within the container based on sensor measured values of the solids content.

The flow measuring device enables monitoring of the degree of contamination of the filter medium and can also, in conjunction with a control and/or evaluation unit, initiate a return pulse for self-cleaning, a CIP cleaning by introducing a cleaning medium in addition to self-cleaning by means of return pulses and/or a cleaning by dismantling the filter device .

The filter device of the specified device can have two of the filter elements, the filter disks of a first of the filter elements each protruding into a space between two filter disks of a second of the filter elements. As a result, in an axial plan view, an overlap area is formed between the filter elements, in which the water to be filtered is subjected to a shear stress, which additionally supports the filtration and at the same time prevents the filter medium from clogging during operation over a longer period of time.

The specified device for treating water can be used in particular as a treatment system for the treatment of kitchen water with a very high protective content, in particular cooking fats and the like.

The process water dispensed by the specified device is of such a high level of purity that it sufficiently meets the requirements of sewer operators in the European Economic Area or other nations for discharge into a sewer system. At the same time The domestic needs of the respective catering establishment can be covered using the process water obtained.

In addition, a reduction in waste disposal costs can be made possible and a product can be created on site for reuse using the process water.

According to a further aspect of the invention, a method for processing water in one of the specified devices comprises the following steps: a) feeding the water to be treated into the sedimentation device, the water to be treated being mixed with a coagulant, in particular, in this sedimentation device in an enrichment path enriched with a Lewis acid, a regulating agent which adjusts the pH of the water, in particular a lye, is added in a regulation path in such a way that flocculation is initiated, in particular with simultaneous precipitation of hardness formers, and finally a decantation of a supernatant of water a sedimented sludge; b) transferring the water pre-cleaned in step a) into the filter device in which further processing takes place through dynamic cross-flow filtration of the water and c) transferring the water filtered in step b) into a reverse osmosis device connected to the filter device for further filtering of the water.

In particular, the flakes formed by the coagulum form crystallization nuclei to remove the hardness formers. This shifts the precipitation equilibrium towards the sedimentation products.

The filter device described above is particularly suitable for separating the remaining solids suspended in the water.

When using two or more filter elements according to one With the device described above, it is advantageous if, within a container, the filter disks of the respective filter elements are moved in the same direction of rotation relative to one another when carrying out the method for building up shear stresses.

The coagulant can advantageously have a Lewis acid, in particular iron (III) chloride, and the regulating agent can have a base, in particular sodium hydroxide solution.

The concentrations of the coagulants and the regulating agent must be adjusted as part of usual dosage experiments in such a way that hydroxide-coated suspended solids containing coagulant are contained in the pre-cleaned water at the beginning of step b).

The properties, features and advantages of this invention described above and the manner in which they are achieved will become more understandable in connection with the following description of the exemplary embodiments, which will be explained in more detail in connection with the drawing. Show it:

Fig. 1 is a schematic diagram of a method and a system according to the invention, and

Fig. 2 is a schematic illustration of a filtration system for use in the method according to the invention.

In the figures, the same technical elements are given the same reference numbers and are described only once. The figures are purely schematic and, above all, do not reflect the actual geometric relationships.

Reference is made to Figure 1, which shows an apparatus 2 for treating water.

The device 2 comprises an inlet 4, through which the water to be treated flows in a flow direction 5, following the device 2 also called flow direction.

The inlet 4 leads into a sedimentation device 6, in which suspended matter and the like are removed from the water to be treated. The sedimentation device 6 begins with an enrichment path 8, in which the water to be treated is enriched with a coagulant 10, also called a flocculant. Seen in the flow direction 5, a first nozzle 12 is arranged in the enrichment path 8 behind the place of enrichment with the coagulant 10, which introduces gas 14 into the water to be treated counter to the flow direction 10. The enrichment path 8 is set up in a direction of fall of the water to be treated, which is not further referenced, so that the gas 14 introduced rises against the direction of fall and mixes the water to be treated with the coagulant 10. In this way, space-intensive mixing machines can be avoided for mixing.

The problem, however, is that flocculation or precipitation begins with the mixing of the water to be treated and the coagulant 10, which from a process engineering point of view should only take place in a flocculation path 16 after the enrichment path 8. In order to avoid this premature flocculation or precipitation, there is a regulation path 18 between the enrichment path 8 and the regulation path 18, in which the flocculation is first started. In order to explain this more clearly, the coagulant 10 in the present exemplary embodiment is considered to be iron(III) chloride, which flocculates from a pH value of the water to be treated of over 7.5.

The pH value after adding the coagulant can be adjusted to a value between 4.0 and 7.3. Optionally, an acid can also be used in addition to the coagulant.

A second nozzle 20 is arranged in the regulation path 18, which introduces air 10 in the flow direction 5, the regulation path 18 being set up against the direction of fall, so that the air 10 rises with the flow direction 5 in the water to be treated. In the In the direction of flow 5, the water to be treated is enriched in front of the second nozzle 5 with a regulating agent 22, here in the form of sodium hydroxide, which adjusts the pH of the water to be treated. The regulating agent 22 is then moved and mixed by the air 10 from the second nozzle 20 in the flow direction 5 together with the water to be treated and the coagulant 10, whereby the pH of the water to be treated exceeds the above-mentioned threshold of 7.5 lifts so that the coagulant 10 begins to flocculate or precipitate. The base, here NaOH, is preferably added in such a way that the pH is between 9.5 and 11.5.

This then happens in the flocculation path 16, whereby ingredients are eliminated from the water to be treated in a manner known per se. This is basically known from DE 10 2015 106 823 Al and will not be explained further.

The water is then transported further through the flocculation path 16 and reaches a sedimentation basin 19, in which coagulum 10 with the bound ingredients to be eliminated from the water sink in the flocculated state as sludge 23 and can be collected in a collecting basin 24. Viewed in the direction of fall, the sedimentation basin 19 should be provided on the lower side with a funnel wall facing a bottom at an angle 21 of 30° to 80°, preferably 40° to 70°, more preferably 50° to 60° and particularly preferred Can be inclined 55°.

A sieve 26 is arranged in the collecting basin 24, through which residual moisture 27 can escape from the sludge 23. This residual moisture 27 can then be returned to the water to be treated in the inlet 4. The mud 23 can also be removed.

The remaining particles contained in the water after the sedimentation device 6 have a more compact shape and therefore a different density than would be the case if the coagulum was used exclusively or if pure NaOH was added. This can be explained by the fact that Calcium or magnesium hydroxide species are formed by adding NaOH. Since coagulum-bound particles are already present at this point, these particles serve as crystallization nuclei and are covered by a calcium or magnesium hydroxide layer. This changes the specific density of the particles.

The sedimentation device 6 is then followed by a filter device 28, in which the water to be treated from the sedimentation device 6 is further filtered in order to eliminate fine particles such as bacteria and viruses from the water to be treated. An accumulation of hydroxides may also have occurred on these fine particles. Overall, the particles have a particularly small particle size with a particular specific density, which prevents settling and thus quantitative removal. The removal of these fine particles formed in the manner described above is a particular challenge of the present method according to the invention due to their particle size and specific density.

The filter device 28 with a filter medium 30 which is mounted so that it can move in a direction 32 at an angle to the flow direction 5 of the water through the filter device 28. The filter medium 30 can basically be moved in any way, for example linearly back and forth.

However, the filter medium 30 is preferably moved in accordance with the technical teaching from the publication WO 2011 033 537 A1, a filter device as is known in wine filtration devices. The filtered water flowing in the flow direction 5 is removed from the center of the filter device 28 and transported further in a manner that cannot be seen in FIG. 1. Water 34 that remains unfiltered can also be returned to the inlet 4.

The mode of operation of the filter device will be explained in more detail below Fig. 2 will be explained in more detail. This filter device is designed to carry out rotation-dynamic cross-flow filtration.

The filter device 28 comprises a container 61 in which a filter element 62 is arranged.

A filter element 62 comprises a plurality of filter disks 63 and a hollow shaft 65, the filter disks 63 being arranged coaxially on a hollow shaft 65. Intermediate regions 70 are formed between the filter disks 63. The filter element 62 or at least parts of this filter element 62 is or are rotatably arranged in the container 61.

The filter disk 63 has a fluid drainage area 72 in its interior, which extends into the hollow shaft 65. Inside the filter disk 63 and in the hollow shaft 65 there is a lower pressure than in the interior of the container 61, so that liquid is sucked into the interior of the container 61 and from there via an axial discharge in the hollow shaft 65. The wall of the filter disk 63 represents the filter membrane. The terms filter medium and filter membrane 30 are used synonymously. The filter membrane 30 can preferably be formed from a ceramic material, in particular from aluminum oxide or zirconium oxide.

The average porosity of the filter membrane 30 for the aforementioned filtration task is between 0.06 and 0.18 mm, in particular between 0.08 and 0.12 mm.

The rotation-dynamic cross-flow filtration DCF (dynamic cross flow filtration) provides a retentate 80, i.e. concentrated sludge phase, comprising non-sedimented coagulum, bacteria, viruses and other solids and a filtrate 90 in the form of filtered water. The filtrate is preferably discharged axially from the container 61 via a fitrate discharge line 66 and the retentate is preferably discharged radially from the container through a retentate discharge line 67. If there are high solids contents, a pump 71 can be installed along the retentate discharge line be arranged so that even a highly viscous retentate 80 can be derived without interference.

In order to prevent the risk of the filter medium 30 becoming clogged, the filter device 28 also has a so-called back-pulse system 68. A counter-pressure generator is used, preferably in the filtrate discharge line 66 of the filter device. This can be a piston lifting device, which generates a counterpulse through a piston movement. If this counterpulse is released into the filtrate, for example, the counterpulse is transmitted to the surface of the filter membrane due to the incompressibility of the liquid, where deposits are detached. This reduces the risk of a so-called fouling layer forming - i.e. a layer that reduces the filter efficiency or filter throughput.

Furthermore, one or more sensors 69, in particular a flow measuring device for flow measurement and/or a turbidity sensor for measuring the solids content, can be arranged to monitor the filter efficiency. This can be arranged along the filtrate discharge line 66. However, it is also possible to achieve both measurements using one measuring device. For example, an ultrasonic flowmeter not only measures the flow rate based on the TOF times (signal time difference when an ultrasonic signal is irradiated in and against the direction of flow) but also the ultrasonic speed. This changes with the solids content in the liquid and makes it possible to monitor the solids content in the water.

Particularly preferably, both for reasons of energy efficiency and for dimensioning reasons, only one filter element 62 is arranged in the container 61, although the use of two or more filter elements would also be conceivable. With two interlocking filter elements, the liquid can shear in the overlay area.

However, a similar effect can also be achieved if one Inner wall one or preferably several baffle plates 73 are arranged to refract a flow. The baffle plates 73 can be distributed circumferentially on the inner wall of the container 61 and have a longitudinal course parallel to the longitudinal axis 100 of the hollow shaft.

The baffles 73 allow for a small tendency for a filter cake to form due to turbulence formed. This ensures a self-cleaning effect of the filter membrane.

At the same time, the above-described design of a filter device 28 only requires a low transmembrane pressure for efficient filtration, which is associated with a low energy expenditure of up to 80% compared to conventional cross-flow filtration devices.

The above-described cleaning effect is particularly favored by the fact that the rotation speed of the filter element 62 is at least 6 m/s on the outer circumference of the filter disks 63 and particularly preferably 6.1 to 8 m/s. These are comparatively high rotation speeds for the aforementioned filter device 28 in other applications, such as wine clarification. At a speed of more than 8 m/s, the mechanical stability of the filter disk can be affected, depending on the material of the filter membrane.

By moving the filter medium, the water to be treated can also be filtered in a significantly smaller space, so that the entire device 2 for treating the water can be accommodated in significantly smaller commercial spaces, such as restaurants. At the same time, the filter device 28 is required to prevent a downstream reverse osmosis system from blocking.

The water emerging from the filter device 28 in the flow direction 5 can now be temporarily stored in a memory 36 before it is finally pumped out of it with a pump 38 and in is finally filtered in a known reverse osmosis device 40 for water treatment, for example to filter out low molecular weight fatty acids. The memory 36 makes it possible to carry out maintenance work, such as flushing operations on the reverse osmosis device 40, without the entire system having to be switched off beforehand. It thus smoothes the water flow between the filter device 28 and the reverse osmosis device 40.

Water 42, which emerges unfiltered from the reverse osmosis system 40, can be fed to a sewer system 44 and/or the inlet 4.

The finally filtered water from the reverse osmosis device 40 can then be stored directly in a collecting basin 46, from which process water 48 can then be removed, for example to operate a toilet. By adding a disinfectant 50, such as chlorine dioxide, new bacteria formation can be avoided.

Alternatively or additionally, the finally filtered water from the collecting basin 46 can be passed into a UV disinfection device 52, through which the water in the collecting basin 46 circulates. It is also possible to direct the water from the reverse osmosis device 40 into the UV disinfection device 52 directly or via an activated carbon filter 54.

Optionally, acid can be added after the filter device 28 or after the reverse osmosis device 40 to adjust the pH of the water in the neutral to slightly alkaline pH range between 7.0 and 8.5. Reference symbol list

2 device for treating water

4 inlet

5 flow direction

6 sedimentation device

8 enrichment path

10 coagulant

11 air

12 nozzle

14 gas

16 Flocculation Path

18 Regulatory Path

19 sedimentation basins

20 nozzle

22 means of regulation

23 mud

24 collection basins

26 sieve

27 residual moisture

28 filter device

30 filter medium or filter membrane

32 direction command

34 unfiltered water / retentate

36 memories

38 pump

40 reverse osmosis device

42 unfiltered water/osmosis rinse water

44 Sewerage

46 collection basins

48 industrial water

50 disinfectants

52 UV disinfection device

54 activated carbon filters

61 containers

62 filter element 63 filter disc

65 hollow shaft

66 Filtrate discharge

67 Retentate derivation 68 Back m p u I system

69 sensors to monitor filter efficiency

70 space

70' gap

71 Pump 72 Overlap area

80 retentate

90 filtrate

100 longitudinal axis

Claims

Patent claims

1. Device (2) for treating water, comprising:

- an inlet (4) for supplying the water to be treated,

- a sedimentation device (6) adjoining the inlet (4) for sedimentation of suspended matter from the water to be treated, the sedimentation device (6) being at least

- an enrichment path (8) for enriching the water to be treated with a coagulant (10) and

- has a regulating path (18) adjoining the enrichment path (8) for introducing a regulating agent (22) which adjusts the pH value of the water to be treated, and

- a filter device (28) adjoining the sedimentation device (6) with a filter medium (30) which is mounted so that it can move through the filter device (28) in a direction at an angle to the flow direction of the water to be treated, and

- A reverse osmosis device (40) connected to the filter device (28) for further cleaning of the water to be treated.

2. Device (2) according to claim 1, wherein the filter device (28) has a container (61) and a filter element (62) arranged therein, the filter element (62) having a hollow shaft (65) and one or more coaxially on the hollow shaft (65) arranged filter disks (63), wherein the filter disks (63) have the filter medium (30) and / or consist of it.

3. Device (2) according to claim 2, wherein the filter element (62) or at least the filter disks (63) are rotatably mounted in the container (61).

4. Device (2) according to one of claims 2 or 3, wherein the filter disks (63) have a fluid drainage area in their interior, which opens into the hollow shaft (65), such that the A filtrate (90) is derived from the filter device (28) along the longitudinal axis (100) of the hollow shaft (65).

5. Device (2) according to one of the preceding claims, wherein the filter medium (30) has an average porosity over the filter medium surface between 5 to 200 nm, in particular between 30 to 100 nm.

6. Device (2) according to one of the preceding claims, wherein the filter medium (30) is formed from a ceramic material, preferably from aluminum oxide and / or zirconium oxide.

7. Device (2) according to one of the preceding claims, wherein the filter device (28) for self-cleaning has a return pulse system (68), preferably a counter-pressure generator, particularly preferably a piston lifting device, which preferably runs along a filtrate discharge line (66) of the filter device (28). is arranged.

8. Device (2) according to one of the preceding claims, wherein the filter device (28) has one or more sensors (69) for monitoring the filter efficiency, preferably a sensor for flow measurement and / or a sensor for measuring the solids content.

9. Device (2) according to one of the preceding claims, wherein the filter device (28) has only one filter element (61).

10. Device (2) according to one of the preceding claims, wherein the container (61) has one or preferably several baffle plates (73) on an inner wall for refracting a flow.

11. A method for processing water in a device (2) according to one of the preceding claims, comprising the steps: a) supplying the water to be treated into the sedimentation device (6), in this sedimentation device (6) in an enrichment path (8) that too treating water is enriched with a coagulant (10), a regulating agent (22) which adjusts the pH of the water is added in a regulation path (18), such that flocculation is initiated and decantation of a supernatant of water from a sedimented sludge (23) occurs; b) transferring the water pre-cleaned in step a) into the filter device (28) in which further processing takes place through dynamic cross-flow filtration of the water and c) transferring the water filtered in step b) into a reverse osmosis device connected to the filter device (28). (40) for further purification of the water.

12. The method according to claim 11, wherein the coagulant (10) has or consists of a Lewis acid, in particular iron (III) chloride, and that the regulating agent (22) has or consists of a base, in particular NaOH.

13. The method according to claim 12, wherein the addition of coagulant (10) and regulating agent (22) in step a) takes place in such a way that pre-cleaned water supplied to step b) contains hydroxide-coated suspended matter containing coagulant.

14. The method according to any one of claims 11 to 13, wherein the filter device (28) exclusively has a filter element (61) which rotates at a rotational speed of at least 6 m/s on the outer circumference of the filter disks, in particular at a rotational speed of 6 to 8 m/s.