WO2006096041A1

WO2006096041A1 - Method for reconditioning a household ion-exchange drinking water filtering cassette and a device for removing nitrates from drinking water

Info

Publication number: WO2006096041A1
Application number: PCT/LT2006/000003
Authority: WO
Inventors: Vytautas Pelakauskas
Original assignee: Uzdaroji Akcine Bendrova Gerva
Priority date: 2005-03-09
Filing date: 2006-02-22
Publication date: 2006-09-14
Also published as: LV13626B; LT2005024A; LT5288B

Abstract

The inventive method for reconditioning a household ion-exchange cassette for filtering a drinking water and device for removing nitrates from drinking water relate to water filter cleaning and to cleaning, regenerating and disinfecting ion-exchange fillers. The method for reconditioning a household filtering cassette consists in regenerating the cassette ion-exchange filler by filtering a 10 % table salt solution and in disinfecting by boiling water, wherein said reconditioning is regularly repeatable at least one time each two weeks. The inventive drinking water ion-exchange filter comprises a container provided with brackets and a funnel, which is arranged thereon and has an opening for receiving a cassette. Said cassette and the filler thereof which occupies the entire volume of the cassette are made of a heat-resistant materials withstanding a temperature of at least 100 °C. Several hard balls made of an inert material are placed in the ion-exchange filler. The container can be provided with a heating element. The device for removing nitrates from water consists of said filter, a cylinder for measuring a salt quantity and a nitrate sensor.

Description

The method of updating a household ion-exchange filter cartridge, an ion-exchange filter for drinking water and a device for filtering nitrates from drinking water

The invention relates to the purification of water by filtration, as well as to the cleaning, regeneration and disinfection of ionic filter media. The invention can be used to purify water, for example, wells, from wells and other sources of water contaminated with nitrates, iron (Fe ^{+ 2} and Fe ⁺³ ), ammonium ions and other undesirable ions, by filtration, especially with ion exchange filters.

Today's consumer of water, especially natural, well or tap water, uses various household filters with disposable filter cartridges for water purification, which quickly become unusable due to large pollution, especially microbiological. Difficulties arise in assessing the contamination of the cartridge and determining the time when the cartridge should be replaced with a new one. Obviously, there are costs for the purchase of a new cartridge and for the disposal of the old cartridge. The creation of a household filter, the cartridge of which would be easy to update when its contamination approaches an unacceptable line, would alleviate the problem. This is especially true in agriculture, areas with developing rural tourism, where there is no water supply, etc.

Considering the known solutions to this problem, it can be noted that most of the methods described in the patent literature for water purification by filters and the corresponding methods for the regeneration of purification agents are industrial, contain sophisticated equipment, and are applicable to pressurized water. To remove some harmful components of water (including nitrate ions), industrial methods use electrolysis (publication of international application WO 03/074430), electrolysis and catalysts (US patent 4956057) and other technologically complex procedures. Electrolysis along with rinsing with a regenerating and disinfecting solution is also used to renew the ion-exchange filter material on an industrial scale (for example, Swiss patent CH 619871 and others). These methods are unsuitable for consumers of household filters for drinking purification due to their complexity and the use of a pressure water stream. water. For example, there is a known method for updating ion-exchange filters for purifying drinking water, in which the ion-exchange filter material is regenerated by a flow of regenerating liquid opposite to the direction of filtration, and is completed by washing with sharp pulses of this stream. This method is used in the metallurgical, chemical industry, where a large amount of water is filtered (Russian patent RU 2149685, publ. 2000).

Due to the fact that the invention covers a very wide area, we consider in more detail only water purification with household filters and cleaning the filter cassettes of such filters, especially the regeneration and disinfection of ion exchanger cassettes.

A known method of updating ion-exchange filters for water, in which the ion-exchange filter material is regenerated by washing with a solution containing chlorine anions, and then with a sulfate solution (UK patent JYa 2139522, publ. 1984).

A known method of updating ion-exchange filters for water and a device for its implementation, in which the ion-exchange filter material is regenerated by washing with a 10% NaCl solution in a special device, when the regenerating solution is fed into the cassette from below. The cassette, its washing device and the filter in which this cassette is used are mutually consistent and represent a rather large and expensive kit. The issue of filter disinfection in this case is not solved at all (publication of international application WO 01/24928, publ. 2001).

The closest is a method of updating a household ion-exchange filter cartridge, in which the filter elements are primarily treated with an aqueous solution of a chemical reagent that dissolves the particles of impurities and regenerates the filter elements. After that, the cartridge is washed with water, water is removed from the filter and 15 minutes purge with air heated to 90 ° C. Then the filter is filled with water and re-regenerated with a chemical reagent (description to author certificate. SU 1328987, publ. 1990).

The method uses chemical reagents. Despite the fact that they are washed with water, their residues remain in the filter material, and subsequently, when using the filter after regeneration, they fall into the water. Therefore, when filtering drinking water, this method of regeneration can be harmful to health. To implement this method is also necessary an additional device for supplying hot air, so this method for household filters is difficult to apply.

Known water filters with replaceable cartridges for filtering drinking water in the home. They are convenient to use and can quite effectively purify, for example, well water from ions of many dissolved salts (German patent DE 4200253).

BRITA, KENWOOD and other filters are widely used with replaceable filter cartridges. Their disadvantage is that after several weeks of operation of the filter, due to microbiological contamination, the cartridge must be replaced with a new one. For example, a filter for drinking water is known having a reservoir, a funnel fitted above it, into the opening of which a conical cartridge filled with filter material or sorbent is inserted. The filter has a lock for the inserted filter cartridge, at the same time fixing the installation date of the cartridge (patent SU 1 801 024, claimed 1989). However, the contamination of the cartridge is estimated only by the number of days of filtering. Neither the contamination of the filtered water nor the amount of filtered water is evaluated. The cartridge of such a filter is disposable.

The closest known one is an ion-exchange filter for drinking water, having a reservoir, a funnel installed above it, in the hole of which a cylindrical cartridge is inserted containing a porous layer of polypropylene, a layer of fibrous ion-based filler, a layer of activated carbon, a layer of granular polymer material and a silver-containing layer for treating drinking water (Patent Application MD 20010309, publ. 2003).

The disadvantage of this and the aforementioned filters is that the resource of the filter layers, including the layer of ionite material, is depleted, the layers of the cartridge are contaminated by mechanical particles and contaminated microbiologically. Then the cartridge is replaced by a new one, and the dirty cartridge is disposed of. Cartridges are expensive, and their disposal pollutes the environment. The degree of contamination of the cartridge during filtering is not sufficiently estimated. It is especially dangerous for human health.

The aim of the invention is to provide a filter for drinking water, the filter cassette of which, if contaminated, would not be discarded, but would be subjected to multiple updates. The goal is achieved through the creation of a method for updating a household ion-exchange filter cartridge, an ion-exchange filter for drinking water and a device for filtering nitrates from drinking water.

In a method for updating a household ion-exchange filter cartridge, the cartridge filler is regenerated by filtering a regenerating solution. What is new is that before regeneration, the cartridge is shaken and rinsed in water; regenerate by filtering a 10% solution of sodium chloride, and the volume of the regenerating solution is up to 20 times the volume of the cartridge; the cassette filler is additionally disinfected by filtering boiling water with a volume up to 20 times the volume of the cassette, or by boiling the cassette for up to 20 minutes, and finally, the cartridge is washed with a water volume exceeding the volume of the cassette up to 20 times, regularly repeating the update.

The anion exchange cassette is updated, in each case, after filtering off the amount of water corresponding to 100 to 600 volumes of cassette filler, but not less than 2 weeks after the start of cassette use. Disinfection is performed immediately after the regeneration of the filler.

The cation exchange cassette is updated in each case after filtering off the amount of water corresponding to about 1000 volumes of cassette filler, or every 2 weeks, or when the cassette is clogged. Disinfection is performed before or after regeneration of the filler.

The proposed ionite filter for implementing this method consists of a reservoir, above which a funnel is installed, having an opening for installing a cartridge, and a cartridge, hermetically inserted into the hole of the funnel. New is that the tank has brackets that support the funnel, the cassette is filled with an ionic filler, it has the shape of two truncated cones, and the taper of the part inserted into the funnel hole is larger than the taper of the rest of the cassette; the cartridge itself is hermetically inserted into the hole of the funnel, the volume of the funnel is not less than 10 times the volume of the cartridge, and the cartridge is suitable for repeated updating in accordance with paragraphs 1 and 2 or 3. The reservoir, funnel and cartridge with ion-exchange material are made of heat-resistant materials, resistant to temperatures of at least 100 ° C. A volume corresponding to 0.15-0.25 of the total volume of the cartridge is left empty in the cassette, and several solid balls made of inert material, the density of which exceeds the density of the filler in 1.1-1.2 times. The reservoir may optionally be equipped with a heating element. To prepare a regenerating solution, a glass for measuring the amount of sodium chloride, the volume of which is up to one and a half volumes of the cartridge, and, optionally, indicators for nitrates (manufactured by Merck) are supplied with the filter.

This invention, using the stage of thermal disinfection, allows you to do without unacceptable in the home chemical disinfecting materials; in addition, there is no danger that residual disinfectants will remain in the filter.

By shaking and rinsing the cartridge in water, the settled mechanical and colloidal particles are separated and washed.

When the cartridge is regenerated with a 10% NaCl solution in a volume equal to 20 volumes of its filler, the cation exchanger completely returns to the Na form, and the anion exchanger to the SG form.

Disinfecting the cartridge with a volume of hot water up to 20 times the volume of the cartridge, or boiling it for up to 20 minutes. in water, microbiological pollution of filters is completely or sufficiently destroyed.

Rinsing the cassette with a 20-fold volume of water, the residues of the regenerating solution and neutralized biomass are finally washed out.

By filtering water from nitrates according to the invention, the nitrate indicator can determine the degree of contamination of the cartridge, and when the pollution exceeds the permissible norms, the cartridge should be updated.

Thus, according to the invention, the ion exchange filter cartridge can be updated many times in the home.

The invention is illustrated by drawings, which depict: Fig.l - the proposed ion exchange filter,

Figure 2 is a graph of the depletion of an ion exchanger filter in a specific case; Figure 3 is a graph of a regeneration of an ion exchanger filter cassette in a specific case; Figure 4 is a graph of a disinfection of an ion exchanger cassette in a specific case.

The proposed ion-exchange filter for drinking water (Fig. 1) contains a reservoir 1, above which a funnel 2 is installed, having an opening for the cartridge, and a cartridge sealed into the opening of the funnel. Reservoir 1 has the brackets that hold the installed funnel 2, the cassette is filled with an ionic filler 6; the filled part has the form of two interconnected truncated cones. The part of the cartridge 4 inserted into the hole of the funnel has a greater taper than the rest of the cartridge 4; the cartridge 4 itself is inserted hermetically into the opening 3 of the funnel 2. The volume of the funnel 2 is no less than 10 times the volume of the cartridge 4, and the cartridge is suitable to be updated many times in accordance with paragraphs 1-3.

The tank 1, funnel 2 and cassette 3 and the ion exchanger are made of heat-resistant materials that are resistant to at least 100 ° C or, if the cassette is to be disinfected by boiling, only the cassette with the ion exchanger is made of resistant materials that are resistant to at least temperature of 100 ° С. The anion exchange resin of the SG form or the cation exchange resin of the Na form can serve as an ionic filler.

A volume of 0.15-0.25 of the total volume of the cartridge for more free shaking and rinsing of the filler is left in the cassette. Several hard balls made of an inert material, the density of which exceeds the filler density by 1.1-1.2 times, are placed in the ionite filler of the cartridge.

For a more convenient disinfection of the filter cartridge or for disinfection of filtered water, the tank 1 may optionally be equipped with a heating element. (Not shown in the drawing).

To determine the degree of contamination of the ion exchanger filter with nitrates, indicators for nitrates (manufactured by Merck) are included in the kit for the drinking water filter, with which you can determine the amount of nitrates in the filtered water, and if it exceeds the permissible value, the cartridge should be updated. To simplify the preparation of the regenerating solution, the device contains a glass for measuring the amount of sodium chloride, the volume of which is about one and a half volumes of the cartridge.

In the case of water purification from nitrates, updating the household anion exchange filter cartridge with a filter (Fig. 1) and the proposed kit is performed as follows.

To filter, for example, well water contaminated with nitrates, take the filter made according to the drawing Fig.l. The filler of his cartridge can be, for example, Purolite A 520E, a large-porous strongly basic ion-exchange resin specially designed for the removal of nitrates from drinking water. Filtered water is poured into the funnel 2. It is filtered by passing through the filler of the cartridge, where ion exchange occurs:

[An] Cl + NO ₃ ^" = [An] NO ₃ + Cl ^" (1)

During the filtering process, the ionite filters are depleted, that is, all SG anionite groups are replaced, and the ion exchangers no longer bind undesired nitrate ions in the water.

Thus, by filtering the amount of water corresponding to 100 - 600 volumes of the cartridge filler, or 2 weeks after the start of using the cartridge, or by using the indicated indicator that the nitrates in the filtered water exceed the permissible norm, the cartridge should be updated. For this, the cartridge 4 is removed, shaken and rinsed in a separate volume of water. So settled and washed away the settled mechanical and colloidal particles. The filter cartridge 4 is inserted back into the opening of the funnel for regeneration. The ratio of the volumes of the funnel 2 and cassette 4 is ~ 10 / l. The funnel 2 and cassette 4 are installed in a vessel for collecting the resulting regenerating solution, for example in tank 1, or on any vessel, the volume of which is at least 20 times the volume of the filler of the filter cartridge.

A 10% regenerating NaCl solution (about 20 volumes of the cartridge) is poured in portions into the funnel, which flows by gravity through the cartridge filler without additional pressure and is collected in the tank. During the regeneration of the cartridge filler, its SG form is restored: [An] NO ₃ + SG = [An] Cl + NO ₃ - (2)

A regenerating solution contaminated with regeneration products (NO ₃ ^" ) is poured out of the tank.

For the regeneration of household ion-exchange filters without additional pressure, increased amounts of a regenerating solution are used: at least 5 times more than recommended in the technical description of the used ion exchanger. To achieve complete recovery of the filler into the SG form, the cassette is regenerated in 20 volumes of 10% NaCl, since in conditions of an unregulated flow of the regenerating solution (when it is difficult to reduce or increase the flow), these amounts provide complete or sufficient regeneration of the filler cassettes. Immediately after this, the cartridge 4 is disinfected by filtering a volume of water at a temperature of 95-100 ° C to 20 times the volume of the cartridge or boiling it for 20 minutes. The cassette update is completed by rinsing it with water.

Such an update of the cartridge is regularly repeated in each case, filtering out a volume of water comprising 100-600 volumes of cartridge filler, but not less than 2 weeks after the cartridge is started to use, optimally every week. Updating can be done multiple times.

In the case of purification of water from iron, ammonium and other undesirable ions, updating the household cation exchange filter cartridge using a filter (Fig. 1) and a device for filtering drinking water from nitrates are performed as follows.

To filter water contaminated with iron, ammonium or other undesirable ions, take a filter (Fig. 1), the cassette filler is a cation exchange resin in the form of Na ⁺ , for example Purolyte C 100E, a strongly acidic ion-exchange resin specifically designed to remove unwanted cations from drinking water. Filtered water is poured into the funnel 2. It is filtered through the filler of the cartridge, where the ion exchange takes place: [Kat] Na ₃ + Fe ⁺³ = [Kat] Fe + 3Na ⁺ (3)

During the filtering process, the ionite filters are depleted, that is, all Na cationite groups are replaced, and the ion exchangers no longer bind undesired cations in the water.

Thus, having filtered the water volume of about 1000 volumes of the cassette filler, either 2 weeks after the cassette is started to use, or when the cassette begins to clog, the cassette should be updated. For this, the cartridge 4 is removed, shaken and rinsed in a separate volume of water. So settled and washed away the settled mechanical and colloidal particles. Cassette 4 is inserted back into the opening of the funnel for regeneration. The volume ratio of the funnel 2 and cassette 4 is -10/1. A funnel 2 and a cartridge 4 are installed in a vessel for collecting the resulting regenerating solution, for example, in a tank 1, or in any vessel, the volume of which is not less than 20 times the volume of the filler of the filter cartridge. A regenerating 10% solution of NaCl (total volume of about 20 volumes of the cartridge) is poured into the funnel in 2 portions, which flows by gravity through the filler of the cartridge and collects by gravity without additional pressure reservoir. During the regeneration of the cartridge filler, its Na form is restored:

[Kat] Fe + 3Na ⁺ = [Kat] Na ₃ + Fe ⁺³ (4)

A regenerating solution contaminated with regeneration products (Fe ⁺³ ) is poured out of the tank.

For the regeneration of household cation exchange filters, increased amounts of a regenerating solution are also used: at least 5 times larger than recommended in the technical description of the cation exchange resin used. To achieve full recovery in the Na ⁺ form, the cartridge is regenerated with volumes of 10% NaCl corresponding to a 20-fold volume of the cartridge, because in conditions of an unregulated flow of the regenerating solution (when it is difficult to reduce or increase the flow), it is precisely these amounts that provide complete or sufficient regeneration of the filter.

After that, the cartridge is disinfected by filtering through it a volume of water at a temperature of 95-100 ° C up to 20 times the volume of the cartridge or boiling for up to 20 minutes. In this case, it is possible to disinfect before regeneration of the cationic filler of the cartridge. In all cases, the cartridge update is completed by rinsing it with water.

This update of the cartridge is regularly repeated, in each case, having filtered out the water volume of about 1000 volumes of the cartridge filler, but not less than 2 weeks after the cartridge is started to use, optimally every week. Updating can be done multiple times.

Both in the case of updating the anion exchange resin and in the case of updating the cation exchange cartridge, a full glass is taken to prepare the regenerating solution, the volume of which corresponds to one and a half volumes of the cartridge, NaCl salts and is dissolved in a volume of water corresponding to 20 volumes of the cartridge.

Such a multiple update of household filtering cartridges for water is not described in the literature and is not used for conventional filter cartridges (BRITA, KENWOOD, etc.).

Examples of the method of updating the ion exchange filter cartridge

Example 1: Update Anionic Filler Cartridges 100 l of natural water contaminated with nitrates (107 mg NO ₃ / l) was passed through a 150 ml filter cartridge filled with nitrate selective anion exchange resin A 520E.

Having filtered 85 l of water, the concentration of nitrates in the filtrate increased to the level of concentration in the filtered water. The depletion of ionite filters in this case is depicted in Figure 2, where the X-axis shows the volume of filtered water in liters, and the Y-axis shows the concentration of NO ₃ ^" anions in the filtered water (upper curve) and in the filtrate, in mg NO ₃ / L. From this curve it is obvious that having filtered 85 liters of water, the cartridge is depleted and must be regenerated. Then, after shaking and rinsing in a separate volume of water, this cartridge is regenerated with 3 liters of 10% NaCl. This is shown in the regeneration graph of Fig. 3: on the X axis shows the volume of the regenerating solution in liters, in the Y axis - the concentration of NO ₃ anions in the regenerant flowing out of the cassette, in g / l. From the regeneration curve it is seen that the volume of the regenerating solution of 3 liters was optimal for complete cassette regeneration, then this cassette is disinfected, for which the volume of hot is filtered through it (95-100 ⁰ C) water corresponding to 10-20 volumes of the cartridge, or the cartridge is removed from the funnel and boiled for 10-20 minutes in water. In one case and in the other case, similar disinfection results are achieved: after these procedures, the microbiological contamination of the filtered water decreases up to 500,000 times.

The graph of Figure 4 shows the disinfection data, where the X axis denotes the time the filter was used, in days; Y axis - the number of bacteria in filtered water, units / ml. During this test, through the mentioned 150 ml cartridge filled with nitrate selective anion exchange resin A 520E, water contaminated with nitrates (total 50 liters) was filtered for two weeks. The number of bacteria in a milliliter of filtered water on the 14th day increased to 4.5 million / ml. After regeneration and the immediately subsequent stage of disinfection (by passing 1.5 liters of water at a temperature of 95-100 ⁰ C), the microbiological contamination decreased to 100 units / ml. Similar results were obtained on the 14th day by disinfection by boiling the cartridge for 5 minutes. in water. As can be seen from Figure 4, the number of bacteria dropped to 100 units / ml. Thus, we can conclude that it is optimal to repeat disinfection every week.

The updated cartridge, after washing it with a volume of water corresponding to 20 volumes of the cartridge, is again suitable for intended use. The experiments showed that the properties of the cassette filler are perfectly restored, updating it at least 25 times. The cassette remains suitable for purification of drinking, for example, well water, and after 50 one-time updates - restrictions are associated only with the terms of use of the filler, defined by the manufacturer, and the heat resistance of the cassette body.

The proposed method for updating a household filter cartridge, an ion-exchange filter for drinking water and a device for filtering nitrates from drinking water, comparing it with the known ones, differs in that according to the invention, when updating the cartridge using the stage of thermal disinfection, it is possible to avoid the use of unacceptable disinfecting materials in everyday life residues of such substances in the filler cartridge. Shaking and rinsing a cartridge with ion exchangers in water, the settled mechanical and colloidal particles are washed out; regenerating the cassette with a volume of 10% NaCl equal to 20 volumes of the filter filler, the cation exchanger completely returns to the Na ⁺ form, and the anion exchanger to the SG form; disinfecting the cartridge with 10-20-fold volumes of hot water (95-100 ° C) or boiling it for 10-20 minutes. fully or sufficiently neutralized the microbiological contents of the cartridge; washing the cassette with 20 volumes of water, the residues of the regenerating solution and neutralized biomass are finally washed out. The ion cassette, if necessary, can be updated about 25-50 times, depending on the material of the filler cassette and the heat resistance of the cassette.

Using the proposed method of updating a household ion-exchange filter cassette, an ion-exchange filter for drinking water and a device for filtering nitrates from drinking water provides a sufficient restoration of the properties of the cassette and is notable for its simplicity and low cost due to the fact that there are enough improvised means for refurbishing the ion-cassette - a vessel for boiling water and cups of NaCl. Updating the ion exchanger for the filter can be repeated many times. In the case of water contamination with nitrates, the consumer, by measuring the amount of nitrates with an indicator, can first of all provide the desired quality of water, and secondly, having an ionic cassette, the consumer can repeatedly update it, there is no need to buy a new one, you do not need to dispose of once used. Using the proposed method of updating a household ion-exchange filter cartridge, an ion-exchange filter for drinking water and devices for filtering nitrates from drinking water are especially effective in rural areas of residence.

Claims

Claim

1. A method for updating a household ion-exchange filter cartridge, including regenerating a filter cartridge filler, such that shake and rinse the cartridge before regeneration in water, mechanically freeing from the precipitate deposited on the filler elements, regenerate filler, filtering 10% sodium chloride solution up to 20 times the volume of the cartridge filler, the cartridge filler is additionally disinfected by filtering boiling water up to 20 times the cartridge volume or boiling the cartridge in ode for up to 20 minutes, and rinse the cassette with a volume of water exceeding the cassette volume up to 20 times.

2. The method according to claim 1, with the fact that the anion exchange cassette is updated, in each case, filtering off a volume of water corresponding to 100 to 600 volumes of cassette filler, but at least 2 weeks after starting to use the cartridge, immediately after the regeneration of the filler by disinfection.

3. The method according to claim 1, with the fact that the cation exchange cassette is updated in each case by filtering out a volume of water corresponding to about 1000 volumes of cassette filler, or every 2 weeks, or when the cassette is clogged disinfection before or after regeneration of the filler.

4. A filter for drinking water, consisting of a tank over which a funnel is installed, having an opening for installing a cartridge, and a cartridge with an ion exchanger, hermetically inserted into the said opening of the funnel, with the exception of the fact that the tank (1) has brackets (5) holding the installed funnel (2), the filled part of the cartridge (4) has the shape of two interconnected truncated cones, the taper of the part of the cartridge inserted into the hole of the funnel is greater than the rest of the cartridge for tight installation of the cartridge (4) in the mentioned hole (3) of the funnel (2), and the volume of the funnel (2) is not less than 10 times the volume of the cartridge (4), thus allowing the filtering of the volume up to 20 times the volume of the cartridge in the ionic filler (6) of the cartridge put some hard balls for the mechanical release of sediment, and the reservoir (1), funnel (2) and (or) cassette (4) with ion exchanger are made of heat-resistant materials that are stable at least at a temperature of 100 ° C.

5. The filter for drinking water according to paragraph 4, characterized in that the balls for the mechanical release of sludge are made of an inert material, the density of which exceeds the density of the filler by 1.1-1.2 times, and the volume 0.15 is empty in the cassette -0.25 of the total volume of the cartridge.

6. The filter for drinking water according to paragraph 4, characterized in that the tank has a heating element.

7. A device for filtering drinking water from nitrates with repeated use of the method of updating the cartridge according to paragraphs 1-3 and using a filter for drinking water according to paragraphs 4-6, characterized in that it additionally contains an indicator (Merck) showing the need (moment) of updating the filter cassettes, and a vessel for measuring the amount of table salt, the volume of which is one and a half the volume of the cartridge, for preparing a regenerating solution.