DEVICE FOR MULTI-STAGE PURIFICATION OF DRINKING WATER

Description

[0001] The present invention relates to a device in which at least two water purification processes are combined in one unit, wherein one process comprises a chelating gel and / or a bactericidal gel for heavy metal removal and / or bacteria removal.

[0002] A wide variety of devices are available on the drinking water purification market, employing different strategies and techniques, some of which are already combined.

[0003] Besides the dominant reverse osmosis technology with the largest market share, there are a variety of devices that use different filtration techniques or distillation processes.

[0004] All known methods have (sometimes serious) disadvantages: The biggest drawback of reverse osmosis is the low yield of drinking water, which rarely exceeds 10% of the water volume used. It is also energy-intensive and removes beneficial elements such as magnesium from the drinking water. In some cases, this magnesium is added back to the drinking water in a complex second step.

[0005] Distillation processes share the disadvantage of extremely high energy consumption. Furthermore, as with reverse osmosis, health-promoting elements are removed, resulting in distilled water that is unsuitable for regular consumption and must be re-enriched with important components such as magnesium salts in a subsequent step.

[0006] Water purification machines that combine multiple filtration technologies in separate units / cartridges require complex piping with corresponding valves or connectors, which are inherently prone to failure and offer the potential for leaks, etc. Furthermore, connections are locations where bacteria, etc., have particularly favorable conditions for growth due to the flow patterns.

[0007] In contrast to the RO technology mentioned above and distillation processes, many purification methods based on filtration (or the combination of different orthogonal filtration techniques) generally operate with high (100%) yield and at line pressure, thus requiring no additional energy consumption. However, this requires a setup with low pressure drop and the use of coarse-grained absorber resins, which reduce the effectiveness of the removal process and overall productivity.

[0008] A well-known and commercially available filter medium is activated carbon, which is used as a bed of particles in linearly flushed cartridges or as a compressed hollow cylinder with radial flushing. From the perspective of productivity and pressure drop, the hollow cylinder represents the ideal design.

[0009] Other well-known media include MetCap® resin (WO2016030021) for removing heavy metals from drinking water and BacCap® resin (DE 102017007273A1) for removing bacteria from drinking water. Both are usually used in cartridges and sometimes in combination.

[0010] MetCap resins consist of a linear polyvinylamine applied to a porous particle and then crosslinked with a bifunctional crosslinker to form a three-dimensional polymeric network. This network contains numerous amino groups in high density and can chelate heavy metals from solutions with high capacity by forming very stable metal-amine complexes, thus removing them. For heavy metals that form only weak amine complexes (e.g., nickel, manganese), additional chelating groups, such as carboxylates or thiols, can be introduced into the polymeric network.

[0011] BacCap resins are also amino polymers, manufactured in a similar way to MetCap absorbers. However, the mixture, stoichiometry, degree of cross-linking, etc., are optimized for antibacterial activity. This antibacterial effect most likely results from the interaction between the at least partially protonated (and therefore positively charged) amino groups of the polymer and the negatively polarized bacterial cell wall. One possible explanation is a direct interaction of the polymeric amino groups with the fatty acids of the cell wall, which is thereby damaged. A second explanation could be the blockage of ion channels in the cell walls by the amino polymer. Ultimately, both explanations lead to the destruction or damage of the cell membrane and ultimately to the death of the bacteria.

[0012] It is particularly important to emphasize that no substances are released into the drinking water to remove bacteria or bind heavy metals. This clearly distinguishes the proposed method from others that release silver, chlorine, or other substances into the drinking water, thereby contaminating it.

[0013] Another advantage of the proposed device lies in its ease of use. Unlike filtration processes such as reverse osmosis, no pressure increase via a pump, which in turn requires electricity, is necessary. The same applies to UV systems on the market, which also require electricity during operation.

[0014] A third method for purifying drinking water is filtration using micro- and nanofiltration processes.

[0015] Another treatment method, specifically for softening drinking water, is the filtration of calcium- and magnesium-containing drinking water through ion exchangers. In this process, calcium and magnesium are bound, and in return, two mole equivalents of sodium are released into the drinking water. This method has come under criticism due to the negative effects of excessive sodium on the heart and circulatory system. A further disadvantage of this method is its limited capacity and the need for frequent exchange or regeneration. These devices are also prone to bacterial growth.

[0016] In stark contrast to the three filter media mentioned first, the filtration capacity of the ion exchanger is exhausted by far the fastest. When using hard water, the resin needs to be replaced or regenerated after just a few days, but at the latest after one to two weeks of proper use.

[0017] Cartridges filled with heavy metal-absorbing resins (e.g., MetCap®), bacteria-removing resins (e.g., BacCap®), activated carbon, or filtration membranes have a lifespan of approximately six months. It is not uncommon for these components to need to be replaced as a precaution before they reach the end of their service life. In addition to the devices described above, there are numerous other devices on the market, or patented, that combine various cleaning technologies in a modular fashion.

[0018] These devices have the advantage that customers can individually replace the respective purification cartridges when exhausted, depending on the characteristics and contamination levels of their drinking water, which can vary greatly from region to region. A disadvantage is that sensors must be installed to monitor the capacity of each individual cartridge, sending individual notifications when parts of the system are exhausted. Alternatively, manufacturers provide protocols that specify certain intervals for replacing individual cartridges.

[0019] The process is complex and consumer-unfriendly. There is a risk that the elaborate protocols or maintenance intervals will not be adhered to, and that the drinking water quality will, on average, suffer rather than improve.

[0020] DE202018101926U1 discloses a two-part filter device for purifying water in aircraft. The document describes an outer hollow cylinder made of activated carbon with internal membranes (specifically hollow filter membranes). The water to be filtered is introduced laterally into the activated carbon, filtered through it, and finally enters the interior of the activated carbon hollow cylinder. The pore size of the activated carbon is preferably 0.5 µm. The pore size of the inner membrane is preferably in the range of approximately 0.2 µm. These relatively large pores were chosen to keep the back pressure of the system low. The authors claim that the device they claim can retain bacteria and heavy metals.

[0021] It is well known that membranes, especially hollow fiber membranes, are used for water filtration in a wide range of applications. For bacterial removal, membranes with a pore size of 0.02 µm (20 nm) are generally used, as larger pore sizes do not retain bacteria and other germs (especially viruses). A significant pressure increase is accepted to ensure bacterial retention. The 200 nm pore size proposed in this publication is significantly larger than the usual 20 nm. Significant bacterial retention therefore seems highly unlikely. Presumably, the large pore size was chosen to minimize back pressure.

[0022] The example of depletion shown is demonstrated using Brevundimonas diminuta. This bacterium is not listed in any drinking water regulations and is rather exotic. E. coli or Pseudomonas aeruginosa are usually used as test organisms.

[0023] Activated carbon itself is largely unsuitable for retaining bacteria. While bacteria are initially retained if the pores are sufficiently small, this is questionable given the 0.5 µm pores of activated carbon. The bacteria then grow within the activated carbon and are subsequently released into the water, thus contaminating it. Against this backdrop, a second purification stage is certainly advisable. However, if the pores in this second stage are as large as described above, effective filtration seems highly doubtful. The same applies to the removal of heavy metals. Activated carbon does not remove heavy metals at all, or only to a very small extent and with very low capacity. Ultrafiltration membranes are completely ineffective at removing heavy metals. This requires membranes with pore sizes in the single-digit nanometer range, which are unsuitable for the intended application due to their high pressure drop.

[0024] In contrast to the device described in DE202018101926U1, which uses only combinations of activated carbon and membrane filtration, the present application proposes a combination with absorbent gels specifically developed for drinking water purification. In particular, the chelating absorbent gel developed by instrAction binds heavy metals effectively, rapidly, and with high capacity. This performance cannot be achieved by simple membrane filtration. At the same time, the particles with antibacterial properties in the proposed setup effectively remove drinking water-relevant germs, especially bacteria, through filtration—unlike activated carbon, which is considered a source of bacteria, and filter membranes with excessively large pore sizes.

[0025] German patent DE10217649A1 presents a process in which a precious metal surface is treated so that, upon contact with water, it releases metal ions into the water, which in turn kill bacteria. Silver is proposed as a preferred precious metal. The principle of action is thus based on the release of antibacterial substances. It is therefore similar to the controversial silvering of ion exchangers for the same purpose. This latter process is characterized by the release of potentially harmful metals. Furthermore, the development of silver-resistant germs is considered a disadvantage. Heavy metals are not removed by this process; on the contrary, the filtrate (according to the invention) ultimately contains more heavy metals than before.

[0026] The present invention is based on the interaction of bacteria with the particle surface in the proposed device and not on the release of antibacterial heavy metal ions into the drinking water. The proposed method not only effectively filters bacteria and other germs from the drinking water, but also removes heavy metals.

[0027] Patent application CH339888A proposes a filter cartridge made of activated carbon with an internal central drain for water purification. The activated carbon is "bonded or impregnated" with "oligodynamically active substances" such as silver or copper, or the salts of these metals. These substances reliably kill bacteria. This is intended to prevent germs from penetrating the activated carbon and contaminating the filtered water with bacteria. This risk is the main criticism of using activated carbon in water purification. The entire device essentially serves to remove chlorine and other undesirable taste substances through absorption. The device itself has since been further developed and is now generally available commercially as compressed activated carbon. The invention proposed in CH339888A has the serious disadvantage that toxic heavy metals such as silver and copper are released into the filtrate.

[0028] As described above, this significant disadvantage is eliminated when using the present invention: In the described device according to the invention, bacteria are removed by interaction with the particle surface of the antibacterial resin. Substances, especially heavy metals, are not released into the filtrate. On the contrary, heavy metals are removed by the filtration of the water through the chelating resin.

[0029] Patent DE3001674A1 proposes a filter containing activated carbon and an ion exchanger. The pH of the water being purified is lowered to approximately pH 3 within the filter, thereby reducing bacterial growth or killing existing bacteria. Simultaneously, biocidal substances are released into the solution to kill bacteria and prevent further growth.

[0030] As in previous publications, this one also attempts to counteract the major problem of activated carbon becoming contaminated with microbes through the release of biocidal substances. The contamination of the filtrate with these potentially harmful substances is accepted as a consequence.

[0031] These disadvantages do not occur when using the device according to the invention, as described above.

[0032] German patent DE202018100396U1 describes a modular water purification system in which two to five different purification processes are combined in a modular fashion. The individual purification stages each address a different group of contaminants that can be found in drinking water. The individual modules are independent of each other and are connected by piping. The modules are individually interchangeable and can be replaced individually once their capacity is exhausted. The modular design has the advantage that individual components can be replaced as needed. A disadvantage is the complex and, in many respects, vulnerable piping system. Furthermore, the removal of bacteria by simple filtration is not yet included in DE202018100396U1.

[0033] The current proposal combines two to three of the most durable cleaning processes in a single cartridge, concentrating all cleaning stages in one module. This is a very space-saving and user-friendly approach, requiring only one cartridge to be monitored and replaced, unlike the two to five proposed in DE202018100396U1. Furthermore, the processes are combined in a three-dimensional arrangement in such a way that they generate only minimal back pressure; this is not present in DE202018100396U1.

[0034] DE 20 2016 100447 U1 discloses a filter comprising an electroactive filter material in a first layer and a second layer. The utility model further discloses a third layer located between the first and second layers.

[0035] The first and second layers exhibit ZETA potential in aqueous environments, allowing viruses and germs to adhere via electroadsorption. The third layer contains an adsorbent (activated carbon or zeolite) to whose surface particles or dissolved substances in the water adhere via physical adsorption (van der Waals forces).

[0036] DE 37 87 659 T2 discloses a filter for removing impurities from water, wherein the filter arrangement comprises a fiber filter for removing solid impurities from the water, a sorbent bed for removing chemical impurities from the water downstream of the fiber filter, and a component for removing microbiological impurities from the water, arranged downstream of the fiber filter and the sorbent bed. The fiber filter and the sorbent bed are arranged cylindrically and allow radial water flow. The component for eliminating microbiological impurities is characterized by a microporous membrane capable of filtering such impurities.

[0037] None of the listed publications combine a rigid hollow cylinder of activated carbon with a particulate bed of chelating and antibacterial resins. Such a combination was previously unknown in the prior art. The same applies to the design with a central drain across the entire module, which is also provided in CH339888A. However, only unacceptable measures for microbial reduction are proposed there. The innovative approach of a multi-stage, radial filter with antibacterial resins is neither provided for nor even mentioned in any of the publications.

[0038] Against this background, the task arises to combine the advantages of known filtration methods in such a way that the disadvantages of the modular design are minimized or do not occur in the first place.

[0039] The problem was solved by a device as defined in claim 1. Advantageous embodiments are the subject of the dependent claims.

[0040] The present invention relates to a device for the multi-stage purification of drinking water by combining orthogonal purification techniques in one module, characterized in that the device comprises a housing (3), a water inlet opening (1), a water outlet opening (2), an outer hollow cylinder (4) filled with activated carbon, and an inner hollow cylinder with a semipermeable wall (5), wherein the inner hollow cylinder (5) comprises a chelating and / or bactericidal gel for heavy metal removal and / or bacteria removal, wherein the chelating gel orthe bactericidal gel or both are filled between an outer activated carbon hollow cylinder and a central drain over the entire length of the hollow cylinder (5), wherein the central drain consists of a tube wrapped with a membrane having openings larger than the particle diameter of the surrounding gel having chelating and / or bactericidal activity, and wherein the membrane has pores smaller than the particle diameter of the surrounding gel having chelating and / or bactericidal activity.

[0041] Advantageously, the housing (3), the water inlet opening (1), the water outlet opening (2), the outer hollow cylinder (4), and the inner hollow cylinder (5) of the device can be manufactured using 3D printing. This enables cost-effective production, and the shape and dimensions of the device can also be customized for the user.

[0042] In the claimed device, at least two of the long-life filtration media or techniques are combined: activated carbon, a heavy metal-binding absorber resin and / or a bacteria-removing resin, and optionally ultrafiltration.

[0043] This is achieved by filling known activated carbon hollow cylinders (4) in a housing (3) with heavy metal-binding and / or bacteria-removing resins (7) (Figure 1, Figure 3). A drain in the form of a hollow cylinder with a semipermeable wall (5) or a hollow fiber membrane or a bundle of hollow fiber membranes (6) is introduced centrally, preferably over the entire length of the hollow cylinder, so that a total of at least two concentric, successively flowed layers with a centered drain are provided.

[0044] The water to be filtered first passes through the outer activated carbon cylinder, followed by the inner cylinder filled with heavy metal-removing absorbent resin and / or bacteria-removing resin. Finally, the water passes through the central outlet, which extends the entire length of both cylinders. This outlet can be designed as a third purification stage – an ultrafiltration hollow fiber membrane.

[0045] The water inlet (1) can be located on the same side as the water outlet (2) for easy replacement / connection to a water purification device (Figure 1, Figure 2 ), or oppositely for linear installation in a piping system ( Figure 3 , Figure 4 ).

[0046] The central flow (5) is essential for optimal flow through the absorber materials while maintaining a low and uniform pressure drop over the entire filter length.

[0047] A linear flow through the filter media results in excessively high back pressure, which either necessitates an additional pump or reduces productivity unacceptably.

[0048] If excessively large particles are selected to reduce pressure, productivity is reduced due to the slow exchange and long diffusion distance between contaminated water and the binding sites within the absorber material. Conversely, if bed heights are too shallow, thus reducing the residence time of the water in the absorber bed, insufficient removal of contaminants results.

[0049] If the inner free activated carbon hollow cylinder (5) is filled with another absorber material (6), without the central drain claimed here, a pressure gradient is obtained along the length of the hollow cylinder, which prevents uniform flow through the gel bed (7) and leads to insufficient removal of contaminants. At the latest after the capacity at the "shortest path" is exhausted, no or only insufficient purification of the water takes place (see Figure 5 ).

[0050] In the case of a filled hollow cylinder with a simple outlet on one side of the cylinder, channels can also be formed on the wall of the inlet ( Figure 6 ) arise (7), which also prevent the flow through the 30 absorber particles and result in no or insufficient removal of impurities due to insufficient contact between water and absorber.

[0051] One solution is the radial arrangement of the separation media (5) and (7) as is already implemented in commercially available hollow cylinders with activated carbon blocks, with central outlet (5) ( Figure 7 and Figure 8 ). This design allows high flow rates with low back pressure, short separation distance and homogeneous, uniform and complete flow (8) while simultaneously ensuring sufficient residence time of the water in the absorber bed.

[0052] The drain can consist of a pipe (6) with multiple perforations and correspondingly small openings that allow the filtered water to pass through without significant pressure drop, but retain the resin.

[0053] Furthermore, the central tube is provided with multiple openings that are large relative to the particle diameter of the resin and is additionally fitted with a suitable filter cloth with a correspondingly small mesh size (6).

[0054] Furthermore, the central flow can be achieved by one or more (bundled) hollow fiber membranes extending over the entire length of the cylinder (6).

[0055] The arrangement can be fitted with opposing inlet and outlet for linear installation in a piping system ( Figure 7 ) or designed with only one connection for inlet and outlet for easy installation in a water purification machine ( Figure 8 ).

[0056] As a variant not in accordance with the invention, a combined hollow cylinder can also be used in which activated carbon and one or more absorber resins are pressed / bonded together in a suitable manner.

[0057] The quantities or volumes of activated carbon, absorber resin, or the quantity and capacity of the central drainage or membrane can be tailored to the requirements of drinking water quality and combined in such a way as to achieve maximum productivity and effectiveness of purification with minimized pressure drop.

[0058] This design allows for adaptation to regional differences and drinking water markets while maintaining the principle claimed here.

[0059] The claimed device combines at least two durable water purification processes in one cartridge, covering an extremely wide range of possible drinking water contaminants ("chlorine", small organic molecules, drug residues, heavy metals, bacteria, viruses, particles, etc.).

[0060] The cleaning elements are arranged in such a way that optimal flow (and thus optimal water-absorber contact) is achieved with reduced pressure drop.

[0061] This design allows for high productivity (large flow area and small particle diameters are possible) with maximum cleaning efficiency, which cannot be achieved with alternative designs.

[0062] At the same time, a compact unit with a minimum space requirement of 20 is achieved, which can be easily monitored by the consumer.

[0063] The combination of different (long-lasting) cleaning techniques reduces the effort required in the design and use of the corresponding machine (fewer or no cables or adapters, only one or two connections, etc.).

[0064] It is also conceivable to simply connect it to a tap (possibly via a flexible adapter) or to install it in appropriate water pipes.

[0065] Despite its outwardly linear structure, it is a radial filtration system with short filtration paths, sufficient residence time of the water in the gel bed, and a very simple design.

[0066] The handling for the end user is greatly simplified compared to a modular system (only one cartridge needs to be replaced / monitored instead of two or three); the same applies to manufacturing, trade, marketing, sales, warehousing, etc.

[0067] In a preferred embodiment, the cartridge can be installed linearly in a water pipe or via a single connection, as is already commonly used on the market.

[0068] The device can easily be combined with all common additional cleaning or storage modules, for example a downstream tank for storing the purified water, or further cleaning technologies such as UV disinfection (in the tank or online), redox filters, etc., or for further use in hot water preparation, CO2 addition module for the production of sparkling water, possible chlorination or hydrogen peroxide addition for subsequent disinfection or preservation, addition of health-promoting ions such as calcium and / or magnesium, etc.

[0069] The device does not affect or impair the type of subsequent water withdrawal or water treatment.

[0070] The performance of the device can be monitored at a suitable location, either at the extraction point or at the points between the individual modules, using appropriate sensors. Suitable sensors include, but are not limited to, pH sensors, conductivity sensors, sensors for monitoring bacterial concentration, ion-selective sensors, UV sensors, etc. A flow cell can measure the amount of water processed.

[0071] In a preferred embodiment, the sensors are connected to a data processing system that monitors the function of the individual modules based on the measured values ​​and issues corresponding messages when a cartridge needs to be replaced or regenerated. The modules can also be replaced purely based on time or volume using the sensors. Depending on the embodiment, the data processing system can initiate automatic regeneration of the water softening module or close a valve to force module replacement as a prerequisite for continued operation.

[0072] The data processing system can be programmed to send a message, e.g. to a mobile device, email, SMS, instant message, etc., in case of exhaustion or errors, informing the consumer of the need to replace the cartridge.

[0073] In its smallest version, the device is suitable for household use and is designed for typical consumption levels. Larger versions can also be used in apartment buildings, residential complexes, restaurants, hospitals, ships, or other facilities with a need for high-quality drinking water.

[0074] The cartridge itself, i.e., the outer housing (3), the water inlet opening (1), the water outlet opening (2), the outer hollow cylinder made of activated carbon (4), and the inner central hollow cylinder with a hollow fiber membrane bundle (6) or permeable wall (6), are preferably made of plastic. They are manufactured using established injection molding processes or 3D printing, or combinations thereof. Post-processing of individual elements, such as drilling, etc., is also possible. The hollow fibers themselves are usually made of polyethersulfone polymers (PES). However, they can also be made of other materials. List of figures:

[0075] Figure 1: Longitudinal section of the double hollow cylinder cartridge with a connection for water inlet (1), water outlet (2), housing (3), hollow cylinder made of activated carbon (4), hollow cylinder with permeable wall (5) or hollow fiber membrane bundle (6), heavy metal binding chelating resins and / or bacteria-removing resin (7). Figure 2 : Cross-section of the double hollow cylinder cartridge with a connection for water inlet (1) and outlet (2); housing (3), activated carbon (4), heavy metal binding chelating resins and / or bacteria-removing resin as filling (7), hollow cylinder with permeable wall (5) or one or more hollow fibers (6). Figure 3: Longitudinal section of the double hollow cylinder cartridge with one connection each for water inlet (1) and outlet (2) (linear structure); housing (3), hollow cylinder made of activated carbon (4), hollow cylinder with permeable wall (5) or one or more hollow fibers (6) heavy metal binding chelating resin and / or bacteria-removing resin as filling (7), frit (8). Figure 4 : Cross-section of the double hollow cylinder cartridge with two connections for water inlet (1) and outlet (concealed on the opposite side), (linear structure), housing (3), activated carbon hollow cylinder (4), heavy metal binding chelating resins and / or bacteria-removing resin as filling (7), hollow cylinder with permeable wall (6) or one or more hollow fibers (5). Figure 5: Unfavorable filtration path of the water in hollow fiber cartridges filled with absorbent gel without a central outlet due to the lower back pressure at the cartridge head (preferred flow direction indicated by the thickness of the arrows in the cartridge), water inlet (1), water outlet (2), housing (3), hollow cylinder made of activated carbon (4), heavy metal binding chelating resins and / or bacteria-removing resin in bed form (7), frit (8). Figure 6 : Channel formation (bypassing) of the water to be filtered (9) in a hollow fiber cartridge without a central outlet with water inlet (1), water outlet (2), housing (3), hollow cylinder made of activated carbon (4), heavy metal binding chelating resins and / or bacteria-removing resin as filling (7), frit (8) and channel formation (bypassing) (9). Figure 7: Advantageous filtration path in a filled hollow cylinder with central outlet and linear structure with opposing inlet (2) and outlet (2); water inlet (1), water outlet (2), housing (3), hollow cylinder made of activated carbon (4), hollow cylinder with permeable wall or hollow fiber membranes (5,6), heavy metal binding chelating resins and / or bacteria-removing resin as filling (7). Figure 8 Advantageous filtration path of a hollow cylinder with inlet (1) and outlet (2) on the same side; water inlet (1), water outlet (2), housing (3), hollow cylinder made of activated carbon (4), (6) hollow cylinder with permeable wall or hollow fiber membranes (5,6), heavy metal binding chelating resins and / or bacteria-removing resin as filling (7), frit (8).

Claims

1. Device for the multistage purification of drinking water by combining orthogonal purification techniques in a module, characterised in that the device comprises a housing (3), a water inlet opening (1), a water outlet opening (2), an outer hollow cylinder (4) filled with activated carbon and an inner hollow cylinder with a semipermeable wall (5), the inner hollow cylinder (5) comprising a chelating and / or a bactericidal gel for the removal of heavy metals and / or removal of bacteria, the chelating gel and / or the bactericidal gel or both being filled between an outer activated carbon hollow cylinder and a central outlet over the whole length of the hollow cylinder (5), the central outlet consisting of a tube wrapped with a membrane having larger openings than the particle diameter of the surrounding gel with chelating and / or bactericidal effect and wherein the membrane has smaller pores than the particle diameter of the surrounding gel with chelating and / or bactericidal effect.

2. Device according to claim 1, characterised in that the central outlet consists of a multiply perforated tube with openings.

3. Device according to claim 2, characterised in that the openings of the multiply perforated tube are smaller than the particles of the surrounding gel with chelating and / or bactericidal effect.

4. Device according to claim 1, characterised in that the central outlet consists of one or more hollow fibre membranes or hollow fibre membrane bundles.

5. Device according to any one of claims 1 to 4, characterised in that the device comprises a pH sensor, conductivity sensor, UV sensor, or sensors for determining the presence of bacteria.

6. Device according to claim 5, characterised in that the sensors issue a warning when defined limit values are exceeded or not reached.

7. Device according to one of claims 1 to 6, wherein the device contains further elements, wherein the further elements are selected from a water tank, a softening system, a hot water preparation system, a system for (UV) sterilisation, redox filters, a CO2 addition unit or a chlorination unit.

8. A device according to one of claims 1 to 7, wherein the housing (3), the water inlet opening (1), the water outlet opening (2), the outer hollow cylinder (4) and the inner central hollow cylinder with permeable wall (5) are produced by 3D printing.