DEVICE AND METHOD FOR PRODUCING DIALYSATE

Description

[0001] The present invention relates to a device and a method for producing dialysate.

[0002] It is known from the prior art to supply dialysis machines with ready-to-use dialysate, ie with a ready-to-use dialysis solution, e.g. from a line system which is connected to a central device for producing the dialysate and which is generally designed to supply a plurality of dialysis machines with dialysate.

[0003] Furthermore, it is known from the prior art to produce the dialysate on the dialysis machine itself, i.e., in a decentralized manner. For this purpose, an RO system (RO = reverse osmosis) for producing ultrapure water can be provided, which can be part of the dialysis machine or implemented as a separate unit. The ultrapure water is mixed with one or more concentrates in the dialysis machine to obtain a ready-to-use dialysate for patient treatment. One disadvantage of producing ultrapure water using the RO process is that the process requires high pressures in the range of 6 to 15 bar, which is correspondingly energy-intensive.

[0004] Documents EP3272375A1 and EP3187211A1 each disclose a device and a method for producing dialysate for dialysis. WO2014 / 128293A1 discloses a water extraction system. WO2009 / 083011A2 discloses a method for regenerating dialysis fluid.

[0005] Documents EP3272375A1 and EP3187211A1 each disclose a device and a method for producing a dialysate for dialysis. WO2014 / 128293A1 discloses a water extraction system. WO2009 / 083011A2 discloses a method for regenerating dialysis fluid.

[0006] The present invention is based on the object of providing a device and a method by means of which energy-efficient dialysate production is possible.

[0007] This object is achieved by a device having the features of claim 1 and by a method having the features of claim 12.

[0008] According to this, the device comprises a first part and a second part designed as a circuit, wherein the first part comprises a water connection or a water container and the primary side of a filter, wherein the filter is designed to produce purified water from the water by forward osmosis, and wherein the second part comprises the secondary side of the filter, a reservoir, a filtrate line leading from the secondary side of the filter to the reservoir, and a line leading from the reservoir to the secondary side of the filter, wherein the container has means for connecting the container to a dialysis machine.

[0009] Preferably, raw water or tap water is drawn from the water tank or from the water connection.

[0010] The container may contain one or more concentrates from which a dialysate can be produced by dilution or dissolution in permeate.

[0011] In the context of the present invention, the term "dialysate" encompasses both a ready-to-use dialysis solution and one or more components thereof.

[0012] The present invention is therefore based on the idea of ​​utilizing the difference in electrolyte concentration between raw water and dialysate / concentrate, and the associated osmotic pressure, to produce dialysate using a suitable forward osmosis membrane in the filter. Forward osmosis is also referred to below as FO for short.

[0013] To produce dialysate, the permeate is mixed with one or more concentrates after production until a physiological or desired electrolyte concentration is reached. Preferably, at least one of the concentrates is located in the reservoir. It is conceivable that at least one concentrate (or all concentrates) is supplied to the second part of the device via a concentrate line.

[0014] The electrolyte concentration (and thus the conductivity as a sum parameter for the electrolyte concentration) is significantly higher in dialysate or dialysate concentrate than in tap water. The electrical conductivity of drinking water (according to the German Drinking Water Ordinance) is a maximum of 2.79 mS / cm, while the electrical conductivity of dialysate is typically 12 to 16 mS / cm. This difference in electrolyte concentration (which does not limit the invention) leads to an osmotic pressure gradient, which is exploited according to the invention for the dialysate production process using FO.

[0015] Preferably, the water, which is preferably tap water, is heated to produce dialysate or concentrate (preferably to 37°C). If this happens right at the beginning of the process, the efficiency of the FO process improves, as the osmotic pressure gradient is directly dependent on temperature.

[0016] A key component of the invention is the use of forward osmosis for dialysate treatment. The focus here is not on the use of used dialysate, but rather on the treatment of raw water, e.g., from the household water supply. The FO membrane therefore preferably also acts as a sterile barrier, enabling effective home dialysis from concentrates (dry, liquid, etc.) for both HD (hemodialysis) and PD (peritoneal dialysis).

[0017] Preferably, the concentrate or dialysate is circulated on the secondary side until the desired final concentration, conductivity, etc. is reached.

[0018] The second part of the device is a circuit. In a preferred embodiment of the invention, the first part of the device is also designed as a circuit, i.e., the water is circulated past the primary side of the filter, and the dialysate or dialysate concentrate is circulated past the secondary side of the filter.

[0019] With a device according to the present invention, for example, one or, better, two small chambers or containers can be filled with ready-to-use dialysate, so that one chamber is always available for dialysate withdrawal. This device is also referred to as a "micro-batch" within the scope of the invention. However, it can also be provided to create a large supply of, for example, 2-5 l (typical for PD) or 70-100 l (typical for HD), for example in a container, especially a bag. Such a device or method is also referred to as a "macro-batch" within the scope of the invention.

[0020] An FO process uses the osmotic pressure gradient to filter water, preferably tap water. The energy-intensive production of permeate through RO is eliminated, and dialysate or concentrate is produced directly. Since the treatment process preferably takes place immediately before the fluid is used, i.e., there is no piping network in between, the effort required to maintain the required hygiene is simplified. Continuous miniaturization also opens up new possibilities for portability. Furthermore, the process is significantly quieter than that of an RO system with its associated pump for pressure generation.

[0021] Preferably, the container is a bag that has partially or entirely flexible walls. A container that has entirely or partially rigid walls, such as a cartridge, is also conceivable and encompassed by the invention.

[0022] According to the invention, several, preferably two, containers are provided and a valve arrangement is provided that is designed to alternately connect the containers to the second circuit. The container not connected to the second circuit can be removed and used for dialysis. At the same time, the other container is filled with the ready-to-use dialysate or concentrate.

[0023] The aforementioned means of the container can be a connector, a tube, a connection for a tube, or other means by which a fluid connection can be established between the interior of the container and a dialysis machine. By means of a connector, the container, which is preferably designed as a bag, can be secured, preferably directly to a counterpart, on a dialysis machine. It is also conceivable for the container to have a tube or an adapter for a tube, by means of which the ready-to-use dialysate or dialysate concentrate can be used, such as in peritoneal dialysis.

[0024] The concentrate preferably contained in the container may, for example, be a bicarbonate concentrate and / or an acidic concentrate designed to produce dialysate.

[0025] The concentrate can be present in the container as powder, granules, slurry or in liquid form.

[0026] A pump is preferably arranged in the first part and / or the second part of the device, also referred to as the "second circuit." If the pump is located in the first part, it can generate a sufficiently high pressure on the primary side of the filter. The pump on the secondary side has the advantage that the dialysate or dialysate concentrate can be repeatedly passed past the filter membrane until the desired concentration or conductivity, etc., is reached.

[0027] To detect the end of the dialysate or dialysate concentrate production, a sensor, preferably a conductivity measuring cell, can be arranged in the second circuit. If this sensor shows a measured value that lies within a target range, the production of the dialysate or dialysate concentrate can be considered complete and the container can be removed for use in dialysis treatment.

[0028] It is conceivable that a concentrate line, which in turn is connected to a reservoir for dialysate concentrate, flows into the second circuit, allowing an additional concentrate to be introduced into the second circuit via the concentrate line. This is useful in cases where the container contains only a portion of the required concentrate, rather than all of it.

[0029] The container can have precisely one compartment containing one or more concentrates that are dissolved by means of the permeate within the scope of the present invention. It is also conceivable for the container to have multiple compartments, each containing one or more concentrates. It is possible for the compartments to be arranged and configured such that they open at staggered intervals, thus ensuring specific osmolarities at staggered intervals.

[0030] The present invention further relates to a method for producing a dialysate using a device according to one of claims 1 to 12, wherein water, preferably tap water, is supplied to the primary side of the filter, wherein the permeate is supplied to the secondary side by forward osmosis, and wherein a dialysate or a dialysate concentrate is supplied to the secondary side of the filter from the container and / or from another source, which dialysate is mixed with the permeate.

[0031] Preferably, the dialysate or dialysate concentrate is circulated on the secondary side until the conductivity and / or a concentration or another parameter correlated therewith corresponds to a target value or lies within a target value range.

[0032] It is conceivable that, in the case of the presence of several containers, one container in the second circuit is filled with the dialysate or with the dialysate concentrate and the other container is emptied for use in a dialysis machine, ie in the context of a dialysis treatment.

[0033] It is advantageous if a physiologically compatible substance, in particular glucose, or a substance to be separated before use as a dialysis solution, in particular magnetic nano iron particles, is added to increase the osmotic pressure on the secondary side of the filter.

[0034] It should be noted here that the terms "a" and "an" do not necessarily refer to exactly one of the elements, although this is a possible interpretation, but can also refer to a plurality of the elements. Likewise, the use of the plural also includes the presence of the element in question in the singular, and conversely, the singular also encompasses several of the elements in question.

[0035] Further details and advantages of the invention are explained in more detail with reference to an embodiment shown in the drawing.

[0036] They show: Figure 1: a schematic flow diagram of a device according to the invention in a first embodiment (micro-batch), Figure 2: a schematic flow diagram of a device according to the invention in a second embodiment (macro-batch) and Figure 3: a schematic flow diagram of a device according to the invention in a third embodiment (2 x micro-batch).

[0037] Figure 1 Reference numeral 1 indicates a heat exchanger at the raw water inlet. Heating the raw water fed to filter 4 increases the effectiveness of the osmosis process. Reference numeral 2 denotes the raw water inlet chamber, which features a ventilation system and / or a level sensor.

[0038] How this Figure 1 As can be seen, the device comprises a first part in the form of the raw water circuit and a second part in the form of the mixed circuit.

[0039] Reference numeral 3 designates the circulation pump in the raw water circuit, i.e., the first circuit according to the invention. 4 denotes the FO filter, 5 the conductivity-temperature measuring cell for raw water and backflow control. Reference numeral 6 designates the raw water circulation valve, and 7 the flush valve for flushing filter 4.

[0040] Number 8 is the drain, number 9 is an A-concentrate pump (dialysis concentrate / acid concentrate) (A-concentrate can also be added later) and number 10 is a B-concentrate pump (dialysis concentrate / bicarbonate concentrate).

[0041] Reference numeral 11 denotes a mixed circuit circulation valve and 11a a shut-off valve which is controlled by a control unit so that it closes as soon as the target conductivity has been reached.

[0042] The reference numeral 12 is the dialysate withdrawal valve and 13b the circulation pump in the mixing circuit, ie in the second circuit according to the invention.

[0043] Reference numeral 14 denotes a concentrate bag, which serves as a collection chamber and can be equipped with ventilation and a level sensor (here the filtrate is accumulated). Preferably, two parallel collection chambers, preferably concentrate bags, are provided, as shown in Figure 3 This allows one chamber to always be filled with dialysate, while the other chamber can always be emptied or used for dialysis treatment.

[0044] Reference numeral 15 is a heater, which can also be located at the position of the heat exchanger. Reference numeral 16 is a conductivity-temperature measuring cell for monitoring the dialysate quality and composition (filtrate + bicarbonate mixing ratio or filtrate + bicarbonate + acid concentrate mixing ratio). Alternatively, a second measuring cell can be used to adjust the B concentrate.

[0045] The process for producing dialysate or dialysis concentrate is as follows: 0. (Initial preparation)

[0046] The FO filter 4 is filled with raw water (tap water) on the raw water side, i.e. on the side of the first circuit.

[0047] The FO filter 4 is filled with physiological solution on the filtrate side or with raw water or permeate (= filtrate) is pressed onto the filtrate side by slight overpressure on the raw water side. 1. Concentrate addition to the mixing circuit

[0048] Example: Volume in the mixing circuit: 800 ml (400 ml in the filter / 400 ml in the circuit) Addition of concentrate: 11.4 ml A-concentrate and 14 ml B-concentrate. 2. Permeate addition to the mixing circuit

[0049] Permeate (filtrate) flows through the FO membrane until the correct mixing ratio is achieved. This determines the osmotic pressure and thus the permeate flow through the membrane.

[0050] Control of the mixing ratio (target Na concentration in the dialysate typically 138 mmol / L) by measuring the dialysate conductivity (typically 12 to 16 mS / cm). 3. Removal of the finished dialysate

[0051] New cycle starts with the addition of concentrate (1 → 2 → 3)

[0052] The entire process can also be designed as a continuous process with continuous concentrate addition, permeate production and dialysate removal.

[0053] It is also possible to install a second collection chamber or container, and preferably a bag, which is filled alternately with the first chamber. This allows dialysate to be withdrawn from one chamber while the other chamber is being filled. This ensures virtually continuous dialysate production.

[0054] The following options are preferred for increasing the osmolarity on the product side of filter 4: In order to increase the osmotic gradient between tap water and dialysate and thus the efficiency of the osmosis process, it is possible on the product side, ie in the second circuit: a. Add a physiologically acceptable additive. Glucose would be a possible substance, which is already present in HD dialysate at concentrations of up to 1 g / l. b. Add a substance that does not remain in the dialysate but is physically or chemically separated beforehand (or retained by the dialyzer). Magnetic nano iron particles would be suitable for this. The particles are added upstream of the filter and separated downstream using a magnetic field.

[0055] It would also be conceivable to return the used dialysate to chamber 2 for reprocessing and thus save energy and water.

[0056] It is also conceivable to support the FO process in the filter 4 by an additional hydraulic pressure or negative pressure from a pump.

[0057] A complementary idea is to test the forward osmosis filter 4 in operation to ensure that the retention function is still guaranteed.

[0058] With the use of forward osmosis technology in sensitive areas such as dialysis, it becomes necessary to ensure or at least monitor the correct functioning of the FO membrane.

[0059] Possible solutions include: 1. Measurement of the resulting osmotic pressure, assuming the FO membrane is functioning correctly. If the membrane is functioning correctly, a transmembrane pressure will build up across the FO membrane (the osmotic pressure). The inlets and outlets of the FO filter can be blocked with valves, and the osmotic pressure can be measured with a pressure sensor. The filter is first filled accordingly (with concentrate on the secondary side and with, for example, tap water on the primary side). The resulting pressure must then remain constant over a certain period of time; otherwise, it can be assumed that direct mixing of the fluids normally separated by the FO membrane is taking place. 2. Priming of the FO filter by forcing tap water onto the permeate side and then measuring the conductivity of the permeate. 3. Determination of the inflowing and outflowing fluid quantities (at the FO filter) as well as their conductivity.These values ​​can then be used to verify the plausibility of the dilution through the FO process. 4. Fill the secondary side of the filter with air. Apply liquid to the primary side and measure the pressure at which the filter "breaks through," i.e., liquid flows to the secondary side (so-called bubble point test).

[0060] Following the macro-batch approach, forward osmosis-assisted dialysate production proceeds as follows: The solution is prepared in one or more batches. The batch can, for example, be a bag containing the concentrates for preparing the solution in solid or liquid form. It is advantageous if the amount of dialysate is sufficient to perform one dialysis treatment (60 L to 250 L).

[0061] A description of a possible embodiment of the method is as follows: Primary page

[0062] The primary side ("feed" side) of the FO membrane is connected to a raw water source (mains water connection). The pressure from the raw water sources or a separate pressure booster (pump or hydrostatic accumulator) ensures that the primary side is overflowed with raw water. The same pressure sources can also be used to initially fill the primary side. Secondary side / secondary circuit

[0063] The secondary side ("product" side) of the FO membrane is connected to the batch, i.e., the container, preferably the bag. A separate pressure booster device (pump or hydrostatic accumulator) ensures that the secondary side is overflowed with solution.

[0064] Preferably, the solution is repeatedly passed along the FO membrane. This means that the batch is connected to the FO filter via a circuit. Priming (filling)

[0065] Initially, only the concentrates are present in the batch in dry form or slightly diluted (as powder, granules, slurry, or liquid). The concentrates are dissolved / diluted with a small amount of solvent (usually tap water). The dilution must be carried out in such a way that the FO membrane used is not damaged by the still significantly elevated electrolyte concentration (no crystallization on the membrane, etc.). All concentrates can be present in the concentrate solution from the beginning or added to the batch over time.

[0066] If the concentrates are added with a time delay, the osmotic pressure gradient can be kept in a range that is optimal for the effectiveness of the FO membrane.

[0067] Options for initial dilution / dissolution of the concentrates and for priming (filling) the secondary side: The filter is prefilled and / or the batch is sufficiently prefilled to start the process and fill the secondary side / secondary circuit. Priming (filling) the secondary side / secondary circuit by creating a vacuum. → The pump on the secondary side draws in the filtrate and fills the batch bag and the secondary side of the filter (the transmembrane pressure is monitored by a pressure sensor). Priming (filling) the secondary side / secondary circuit by overpressure on the primary side. → The pressure source on the primary side pushes the filtrate and fills the batch bag and the secondary side of the filter (the transmembrane pressure is monitored by a pressure sensor). Use the fluid from the previous filling process as the priming solution to prime the filter.

[0068] It is possible to initially operate / fill only the filtrate side with minimal, ie reduced, circulation -> reduced secondary volume (suitable, small bag shape, FO filter with reduced secondary volume.

[0069] Later addition of water, e.g., through volume from the FO membrane or through manual addition to the batch. Goal: Lower priming volume Preparation of the solution

[0070] The concentrated solution is passed past the secondary side of the FO membrane. The high osmotic pressure gradient between the raw water and the solution leads to a continuous flow of filtrate across the FO membrane into the batch. In a closed batch, the osmotic pressure gradient and thus the production of permeate decrease over time. However, a gradient remains until an electrolyte concentration typical for a physiological solution is reached (electrolyte concentration approximately 0.15 mol / L in the finished dialysate).

[0071] Stop production: A volume-rigid system is filled -> target volume is reached / static pressure increases → measure the pressure or the process will stop automatically (p_static = p_osmosis). Shutdown via conductivity (LF) or LF only as a protection system. Shutdown via weight determination. Time-controlled measurement of TMP (transmembrane pressure) / measurement of filtrate flow. The process ends as soon as the mixing ratio of A-concentrate to permeate is 1:35 (= mixing ratio for the finished concentrate). Tank (volume-rigid)

[0072] Advantages of the present invention are in a preferred embodiment: An FO process (particularly FO membranes with aquaporin technology) utilizes the osmotic pressure gradient to filter tap water. The energy-intensive production of permeate is "omitted," and dialysate is produced directly. Nevertheless, comparatively high filtration rates are achieved: FO filter (e.g., Aquaporin Inside HFFO2): 22.60 liters / m² / hour (25°C / 5.8% NaCl solution vs. tap water) RO filter, e.g., 50 liters / m² / hour at 15 bar. Since the treatment process takes place immediately before the fluid is used, i.e., there is no piping network in between, the effort required to maintain the required hygiene is simplified. Continuous miniaturization also opens up new possibilities for portability. In an FO process, the energy-intensive production of filtrate (permeate) is omitted, and physiological solution (dialysate) is produced directly.The production of permeate via an FO membrane is technically less complex compared to all the processes mentioned (only one FO membrane instead of several adsorber cartridges, no piping systems (designed for high pressures)) and is therefore suitable for home systems such as those commonly used in PD dialysis. The entire system is therefore more space- and cost-efficient, less complex, and easier to clean. In addition, better filtrate quality can be expected compared to adsorber technology, as the retention rates of the FO membranes almost match those of RO membranes (RO technology currently achieves the maximum retention rate in filtration processes) □ Important in the production of hygienically particularly critical PD solutions that are infiltrated directly into a patient's installation space.Shipping of dry concentrate bags or highly concentrated concentrates instead of the current ready-to-use liquid solutions (lower transport weight, better shelf life and freedom from germs). Overall, the technology is suitable for the decentralized, needs-based production of physiological and hygienic solutions. The process is significantly quieter than an RO system with an associated pump for pressure generation → better suited for the home environment.

[0073] Figure 2 shows a schematic view of a device for producing a macro-batch: Reference numeral 1 indicates the water connection, 2 the circulation pump of the mixing circuit, 3 the FO filter, 4 the conductivity-temperature measuring cell for raw water and backflow control (could also be arranged between 5 and 2 in the suction line), 5 the container, preferably bag with concentrate(s), and 22 the drain. As can be seen from Figure 2As can be seen, in this embodiment the first part of the device is not designed as a circuit.

[0074] The FO filter is preferably disposable / semi-disposable and is replaced as needed (fixed interval, after a certain volume of filtrate, "bubble point test" / "pressure hold test fails).

[0075] The following options / expansion possibilities are available: Air separation in the circuit to prevent air at the filter. Increasing the pressure on the raw water side to increase the raw water flow or to overlay the FO process with hydrostatic pressure (→ increasing the filtration rate). Combination with electrodialysis to increase the (volumetric) concentration of the freely mobile electrolytes by applying an electric field → increased concentration of the electrolytes at the filter. Introduction of a physiologically neutral substance to increase the osmotic pressure. Introduction of a substance that can be separated in a further step (FO agent) - subsequent separation of the agent from the product (as is common today), e.g. via a thermal process, filtration or by separation in a magnetic field (when using a ferrofluid as the agent). Reuse of already used dialysate by feeding the used dialysate on the primary side / bag emptying -> lower waste weight and volume.Used dialysate is reused throughout the dialysis Used dialysate is used to start the process (fill the secondary circuit) Monitoring of the transmembrane pressure (limits specific to FO filters) to avoid damage to the FO filter (→ important for aquaporin filters) FO membrane tests to monitor the integrity of the filter Filling / emptying of several bags at the same time.Conductivity monitoring in the batch, in the intake line before or after the FO filter to control the filtrate production process. Heating and / or heat exchanger in the primary or secondary circuit (preferred) to bring the raw water / filtrate to an optimal temperature for the FO process (25 to 50 °C). Additional ultrafilter in the feed line before the FO circuit to retain high levels of microbiological, chemical, or physical contaminants, thus reducing fouling of the FO filter and achieving longer service life. Additional ultrafilter after the FO circuit to retain any remaining microbiological (endotoxins), chemical, or physical contaminants. Testing of the FO filter (e.g., measuring osmotic pressure) before and after batch filling to ensure filter effectiveness and thus the validity of the batch. Batch release only after successful testing (e.g.,) In principle, all described implementations within the micro-batch approach are analogous.

[0076] Possible areas of application of the invention are: Produce HD solution / batch for one treatment e.g. 70L Produce PD solution / batch for one treatment or several bags (e.g. 5 L bags) Mobile production of NaCl solution (after disasters, emergencies or in case of poor energy supply) Fill Genius tank with FO system, produce acute bags

[0077] Figure 3 shows an essentially Figure 1 corresponding device, however, two containers 14 are provided, which can be fluidically separated from the second circuit, ie, from the mixing circuit, or connected to it by valves V. During the preparation of the solution, one container 14 is alternately connected to the circuit and the other container 14 is removed and used with a dialysis machine, ie, as part of the treatment.

Claims

1. An apparatus for preparing dialyzate, wherein the apparatus has a first part and a second part that is configured as a circuit; wherein the first part comprises a water connection or a water container (2) as well as the primary side of a filter (4); wherein the filter (4) is configured to prepare purified water from the water through forward osmosis; and wherein the second part comprises the secondary side of the filter (4), a reservoir (14), a filtrate line that leads from the secondary side of the filter (4) to the reservoir (14), and a line leading from the reservoir (14) to the secondary side of the filter (4), with the reservoir (14) being a container having means for connecting the container to q dialysis machine, characterized in that a plurality of containers are provided; and in that a valve arrangement is present that is configured to connect the plurality of containers alternatingly in fluid communication with the second part of the apparatus.

2. An apparatus in accordance with claim 1, characterized in that the container is a bag that is designed with flexible walls overall or in part or is a cartridge that is designed with rigid walls overall or in part.

3. An apparatus in accordance with claim 1 or claim 2, characterized in that the first part of the apparatus is also designed as a circuit.

4. An apparatus in accordance with one of the preceding claims, characterized in that dialysis concentrate is located in the container.

5. An apparatus in accordance with one of the preceding claims, characterized in that the means of the container are a connector or a tube or a connector for a tube.

6. An apparatus in accordance with one of the preceding claims, characterized in that a bicarbonate concentrate and / or an acid concentrate is present in the container that is formed for the preparation of dialyzate.

7. An apparatus in accordance with one of the preceding claims, characterized in that a plurality of compartments are provided in the container in which one or more concentrates are respectively present.

8. An apparatus in accordance with one of the preceding claims, characterized in that the concentrate is present in the container as a powder, a granulate, a slurry, or in liquid form.

9. An apparatus in accordance with one of the preceding claims, characterized in that a pump (3; 13b) is provided in the first part of the apparatus and / or in the second part of the apparatus.

10. An apparatus in accordance with one of the preceding claims, characterized in that a sensor, preferably a conductivity measuring cell (5; 16) is arranged in the first part of the apparatus and / or in the second part of the apparatus.

11. An apparatus in accordance with one of the preceding claims, characterized in that a concentrate line that is centrally connected to a further reservoir containing a dialysis concentrate opens into the second part of the apparatus.

12. A method of preparing dialyzate in accordance with an apparatus in accordance with one of the claims 1 to 11, characterized in that water is supplied to the primary side of the filter (4); in that the permeate is supplied to the secondary side by forward osmosis; and in that a dialysis concentrate that is mixed with the permeate is supplied to the secondary side of the filter (4) from the container (14) and / or from another source; and in that a plurality of containers (14) are present in the second part of the apparatus, wherein one container (14) is filled with the dialyzate or with the dialysis concentrate and the other container (14) is emptied for use in a dialysis machine.

13. A method in accordance with claim 12, characterized in that the dialyzate or the dialysis concentrate is conveyed in the circuit on the secondary side of the filter (4) until the conductivity and / or a concentration or another parameter representative for these parameters corresponds to a desired value or is in a desired value range.

14. A method in accordance with one of the claims 12 to 13, characterized in that a physiologically compatible substance, in particular glucose, or a substance to be separated prior to the use as a dialyzate, in particular magnetic iron nanoparticles, are added to increase the osmotic pressure on the secondary side of the filter (4).