WO2013189959A1

WO2013189959A1 - Water disinfection system

Info

Publication number: WO2013189959A1
Application number: PCT/EP2013/062678
Authority: WO
Inventors: Michael Reidtz WICK; André KAZARIAN; Poul Fogh
Original assignee: Adept Water Technologies A/S
Priority date: 2012-06-21
Filing date: 2013-06-19
Publication date: 2013-12-27

Abstract

The present invention relates to a water disinfection device comprising a chamber body for disinfection of water and a filter means, wherein the chamber body comprises means for providing a disinfectant from the water or air in the chamber body and has a water inlet, wherein the filter means is substantially impermeable to microorganisms and has a water outlet, and wherein the chamber body and the filter means are in liquid communication and wherein water inters the chamber body through the water inlet and flows from the chamber body through the filter means and out through the water outlet. The invention also concerns a method of producing disinfected water for consumption comprising leading water to be disinfected through a water disinfection device of the present invention.

Description

TITLE: Water disinfection system FIELD OF THE INVENTION

The present invention relates to a water disinfection device comprising a chamber body for disinfection of water and a filter means. Furthermore the present invention relates to a method of producing disinfected water for consumption comprising leading water to be disinfected through a water disinfection device of the present invention.

BACKGROUND OF THE INVENTION

One of the great advances in civilization is the availability of clean, safe drinking water. One of the major problems here is the microbiology. The methods of providing microbiological safe water has evolved, the first major step being chlorination, which was introduced in the United States in the 1930es. Since then a number of new techniques, such as sterile membrane filtration, UV radiation, more powerful oxidants, metal ions and combinations thereof has increasingly been used to ensure safe drinking water to an ever increasing world population.

Water disinfection methods can be categorized in many ways. One important way is whether or not there is any residual effect, i.e. if the water has none or limited microbiological growth after the point of treatment. Residual effect is advantageous if the pipeline downstream is contaminated, or if the water is stored before use.

In this categorization, only chemical disinfectants provide any residual effect. A major group of disinfection chemicals are oxidants, oxidizing the membranes and internals of microorganisms, thus killing them. The contact time and concentration of specific types of chemicals are determining factors in the reduction rate. This is known as the CT factor, and is throughout the scientific and industrial communities acknowledged as a good descriptor for disinfection efficiency, and the CT factors are measured for many microorganisms and widely available. Until recently, any chemical disinfection required a chemical supply, but as described in PCT/DK2009/000215, Adept Water Technologies has developed a technology that can generate chlorine from the salt content of normal freshwater - thus in general eliminating the requirement for a chemical supply. In the case of water with too low mineral content, addition of a chloride salt beforehand may be performed. This is already done in drinking water systems where desalinated seawater is mineralized for better taste and washing properties. Certain microorganisms in water have a high CT factor towards chlorine (meaning they are hard to kill), and the power consumption for generating large amounts of chlorine is high, other ways of increasing the contact times must be considered. A membrane impermeable to microorganisms is the usual solution. If this is added after the disinfection process, microorganisms trapped here will experience a constant high concentration of disinfection agent, and thus be killed.

Such membranes, typically known as a sterile filter, ensure that no microorganisms pass, thus leaving them on the surface, and in the pores of the membrane. This works fine for a while, and if the filter is replaced or cleaned frequently, such a system may work well. Membrane manufacturer's are well aware of this and provide cleaning instructions for their systems. However, if the membrane is not replaced or cleaned in time, the microorganisms trapped in the membrane may, if not completely killed, actually grow through the membrane. A further disadvantage of some sterile filters is that water disinfectants, typically chlorine, may oxidize and deteriorate the membranes.

SUMMARY OF THE INVENTION

The present invention concerns a water disinfection device combining two different technologies. The first is an in-situ disinfectant generation step, where the disinfectant is of the oxidative type. The second is a membrane withholding microorganisms and capable of withstanding the oxidative disinfectants.

Accordingly, in a broad aspect the present invention relates to a water disinfection device comprising a chamber body (2) for disinfection of water and a filter means (7), wherein the chamber body (2) comprises means (3,4) for providing a disinfectant from the water or air in the chamber body (2) and has a water inlet (1), wherein the filter means (7) is substantially

impermeable to microorganisms and has a water outlet (9), and wherein the chamber body (2) and the filter means (7) are in liquid communication and wherein water inters the chamber body (2) through the water inlet (1) and flows from the chamber body (2) through the filter means (7) and out through the water outlet (9).

In a further aspect the present invention relates to a method of producing disinfected water for consumption comprising leading water to be disinfected through a water disinfection device comprising a chamber body (2) for disinfection of water and a filter means (7), wherein the chamber body (2) comprises means (3,4) for providing a disinfectant from the water or air in the chamber body (2) and has a water inlet (1), wherein the filter means (7) is substantially impermeable to microorganisms and has a water outlet (9), and wherein the chamber body (2) and the filter means (7) are in liquid communication and wherein water inters the chamber body (2) through the water inlet (1) and flows from the chamber body (2) through the filter means (7) and out through the water outlet (9).

The combined requirement for a stand-alone disinfection unit that provide optimum water disinfection and is easy to use can be summarized in the following five bullet points:

• It must remove microorganisms from water,

• It must have a high immediate effect

• It must provide an oxidative disinfectant that has a residual effect

• There must be no chemicals handled or added to the water

• It must include a membrane that can withstand the disinfection chemicals and provide long contact time for microorganisms, yet allow the disinfection chemicals to pass.

The present invention provides all of these advantages with the described solution.

Further objects and advantages of the present invention will appear from the following description, and claims.

DESCRIPTION OF THE INVENTION

The present invention concerns a water disinfection device comprising a chamber body for disinfection of water and a filter means, wherein the chamber body comprises means for providing disinfectant from the water or air in the chamber body and has a water inlet, wherein the filter means is substantially impermeable to microorganisms and has a water outlet, and wherein the chamber body and the filter means are in liquid communication and wherein water inters the chamber body through the water inlet and flows from the chamber body through the filter means and out through the water outlet.

The water disinfection device of the present invention may be a stand-alone device. Alternatively, the water disinfection device of the present invention may be a part of a system for disinfection of water. The present invention is in particular useful for disinfection of water containing microorganisms having a high CT factor for chlorine, but also ozone and/or radicals.

As used herein "CT factor" is intended to mean the mathematical product of contact time and concentration of chemicals that are determining factors in the reduction rate of microorganisms. The CT factor is throughout the scientific and industrial communities acknowledged as a good descriptor for disinfection efficiency, and the CT factors are measured for many microorganisms and widely available, and in Table 1 (Safe Water System (SWS) - Effect of Chlorination on Inactivating Selected Pathogens) a number of non-limiting examples of such factors are shown (Table 1 is shown at the end of this document after figures 1 and 2 in 2 pages). As used herein "a chamber body" is intended to mean a housing, such as a container or tubing made of metal or plastic materials, for holding water to be disinfected and containing the means for providing a disinfectant from the water or air, wherein a non-limiting example of such means for providing a disinfectant is a stack of electrodes, e.g stacked electrode plates. The section of the housing e.g. the tubing may or may not be of different dimensions than the piping. As used herein "a filter means" is intended to mean a system that separate particles and

microorganisms from a liquid phase, such as the water. Filters operate mainly by stopping particles larger than a certain dimension, but other characteristic may also be referred to as the filtering function. Filters may be of the membrane type, where the membranes have a characteristic pore size or is selective in other ways. They may also be simple plates with holes drilled in them, or a sintered material

As used herein "substantially impermeable" is intended to mean that the majority of

microorganisms are stopped by the filter, in particular more than 80% or the microorganisms are stopped, typically, more than 90%, more than 95%, more than 98%, more than 99%, more than 99,9%. Thus, in a further embodiment substantially impermeable to microorganisms mean that the majority of microorganisms are stopped by the filter means. Typically, more than 80%, such as more than 90%, more than 95%, more than 98%, more than 99%, more than 99,9%.

As used herein "the chamber body and the filter means are in liquid communication" is intended to mean that liquid may flow directly between the chamber body and the filter means or indirectly through a pipe or tube, basically the water that has passed through the chamber body will also enter the filter means.

Typically, the water to be disinfected comprises some amount of chlorine, in the form of chloride ions, and preferably the water to be disinfected contain at least 2 ppm, such as at least 5 ppm, such as at least 7 ppm, e.g. at least 10 ppm of chloride ions. Typically, the water to be disinfected contain from 10 ppm to 250 ppm of chloride ions, the latter number being the upper definition of drinking water. It is obvious to the skilled person, that the higher the chloride content, the less energy is required to produce a given amount of chlorine.

In a further embodiment the water to be disinfected contain at least 10 ppm of chloride ions and has an electrical conductivity of at least ΙΟΟμΞ/αη. Typically, the water has an electrical conductivity of from 200 μ8/αιι to ΙΟΟΟμΞ/αη. The skilled person will know that it is possible if the chloride content is high to operate at lower conductivities. It is obvious to the skilled person, that the higher the conductivity, the lower voltage is required to produce a given amount of chlorine.

As used herein "natural sources" is intended to mean that the water to be disinfected comes from the environment and is not the product of a chemical reaction, in particular the water to be disinfected may without limitation come from a lake, a sea, an ocean, a river, a well, a pond or a reservoir. Such water from natural sources contains species already present in the water before treatment.

The water to be disinfected is typically ground water or comes from a lake, a sea or a river and contains a natural amount of chloride ions. However, the water to be disinfected may also have no chloride ions present or have a low content of chloride ions in which case chloride ions are added to the water before or during disinfection in the device of the present invention.

In a further embodiment the chloride ion content comes from natural sources. In another embodiment the chloride ion content comes from adding chloride ions to the water before disinfection. In a still further embodiment the chloride ion content comes from natural sources and from adding chloride ions to the water before disinfection.

As used herein "an integrated part" is intended to mean that the chamber body and the filter means are in the same unit or are so connected that the water to flows directly from the chamber body through the filter means without passing through a conduit or tube, in particular the structural parts of the chamber and the filter may be the same or may be connected in a fashion that, while no clear distinction can be made between one and the other, still offer both functionalities.

In a further embodiment the filter means is an integrated part of the chamber body. In a still further embodiment the filter means is separate from the chamber body. Alternatively, the filter means may be a combination of an integrated filter means and a filter means is separate from the chamber body.

In a further embodiment the filter means, such as a membrane, is made of a material that does not degrade in the presence of an oxidizing disinfectant. Typically, the oxidizing disinfectant is selected from chlorine, ozone, peroxides, and/or free radicals.

As used herein "a polymer material which does not degrade in the presence of an oxidizing disinfectant" is intended to mean a polymer material known to the person skilled in the art and may without limitation be PolyEtherSulfonate (PES) and Flourinated membrane (PTFE/PVDF etc.) and other types of polymer are also resistant to chlorine and other oxidizing species.

In a still further embodiment the filter means is made of a polymer material which does not degrade in the presence of an oxidizing disinfectant. Typically, the polymer material is selected from a fluorinated hydrocarbon polymer or a polyether sulfonic polymer.

As used herein "a ceramic material" is intended to mean a type of solid crystaline materials, typically metal salts, which offer good resistance to oxidizing agents and are without limitation selected from Diatomite, Silicon Carbide, Alumina Oxide, Zirconium Oxide, stabilized Zirconium Oxide, or mixtures thereof. Such ceramic materials are known to the skilled person, and may without limitation be selected from LiqTech's silicon carbide filters.

Alternatively, the filter means comprises a ceramic material. Typically, the ceramic material comprises any one of Silicon Carbide, Alumina Oxide, Zirconium Oxide, stabilized Zirconium Oxide, or mixtures thereof. The ceramic material may also comprise Titanium oxides. In particular the ceramic material comprises any one of Silicon Carbide, Alumina Oxide, Zirconium Oxide, stabilized Zirconium Oxide as a major component, which means that more than 50% is selected from any one of Silicon Carbide, Alumina Oxide, Zirconium Oxide, stabilized Zirconium Oxide. In addition the ceramic material comprises any one of Silicon Carbide, Titanium oxide, Alumina Oxide, Zirconium Oxide, stabilized Zirconium Oxide as a major component, which means that more than 50% is selected from any one of Silicon Carbide, Titanium oxide, Alumina Oxide, Zirconium Oxide, stabilized Zirconium Oxide.

In a further embodiment the disinfectant provided is selected from chlorine, ozone, peroxides, and/or free radicals. As used herein "a means for providing a disinfectant from the water or air in the chamber body" is intended to mean an electrochemical elimination or reduction device for providing chlorine or other oxidative species generated from ions in the water or ozone, generated from the oxygen in the air. An example of such an electrochemical elimination or reduction device is disclosed in

PCT/DK2009/000215. In a still further embodiment the means for providing the disinfectant is two or more pair of electrodes capable of converting the water or air in the chamber body and/or the salts therein to disinfectants.

The water entering the water disinfection device may be treated to soften the water before entering the chamber body. This has the advantage that the forced precipitation of hardness on the electrodes is prevented and thus ensuring uninterrupted disinfection. Thus, in a further embodiment the water has been softened before entering the water inlet. Preferably the water has been softened to a hardness level, which measured by the dH scale should be below 5.

In a further embodiment a pre-filter has been provided before the water enters the water inlet. This pre-filter shall be of a type that removes particles and eventually chlorine already in the water, thus ensuring that the residual disinfection level is controlled. A preferred solution is a net or a sieve type filter combined with an activated carbon filter. Another solution is an activated carbon filter combined with an ion-exchanger.

In a still further embodiment the pre-filter is a combination of filters and optionally a softener, such as one or more of a coarse pre-filter, an active carbon filter and/or a fine pre-filter, e.g. the prefilter is a coarse pre-filter, an active canbon filter, a fine pre-filter and an ion exchanger that softens the water.

In a further embodiment a water tank is provided after the filter means. This ensures that a large range of water may be disinfected as a stand-alone unit. Optionally a pump or pressure switch, or both is provided after the water tank to control the supply of disinfected water through the water outlet. Furthermore, an optional vibration dampener may be provided after the water tank, such as after the pump and/or pressure switch, to minimize noise and vibrations.

In a still further embodiment a recirculation system is provided such that disinfected water leaving the chamber body may be recirculated back to the chamber body. Such recirculation may be performed with a recirculation valve. Typically, the recirculation system is provided after the water tank, such as after the pressure and pump to allow the water leaving the water tank to be

recirculated to the chamber body for further disinfection. This ensures that the water in the tank is ready to use for longer time periods.

In a still further embodiment no chemicals are added to the water during or after disinfection. In a still further embodiment chemicals are added to the water before entering the chamber body. Such adding of chemicals is typically referred to a boosting the chloride level.

The present inventors have provided a new device for killing bacteria described in PCT/DK2009/000215, containing a pair of parallel and symmetrically arranged perforated electrode plates, which electrodes are also suitable for use in the present invention. Thus, in a further embodiment the means for providing the disinfectant comprises a pair of parallel and symmetrically arranged perforated electrode plates having a suitable distance, wherein each pair is optionally fitted with a fuse, wherein a suitable current density is applied, and wherein the plates are made of a conductive material and are arranged in a perpendicular plane. Typically, the pair of parallel and symmetrically arranged perforated electrode plates has/have a distance selected from 1-5 mm, such as 1, 2, 3, 4 or 5 mm and combinations thereof. The electrodes are arranged in pairs that may have the same distance between the plates or may have different distance between the plates, if more than one pair of electrodes is present. Typically, from 1 to 11 pairs of parallel and symmetrically arranged perforated electrode plates are present, such as 1-10, 2-9, 3-8, 4-7, or 5-6 pairs of parallel and symmetrically arranged perforated electrode plates. When a pair of parallel and symmetrically arranged perforated electrode plates is used, such pair of parallel and symmetrically arranged perforated electrode plates is optionally arranged such that in a perpendicular plane view 60 - 100% of the area of passage is covered by the electrodes.

Typically, the current density is above 5 mA/ cm², such as from 5 to 30 mAJ cm².

In a further embodiment the polarity of the electrodes can be reversed. In a further aspect the present invention relates to a method of producing disinfected water for consumption comprising leading water to be disinfected through a water disinfection device of the present invention, such as a water disinfection device comprising a chamber body for disinfection of water and a filter means, wherein the chamber body comprises means for providing a disinfectant from the water or air in the chamber body and has a water inlet, wherein the filter means is substantially impermeable to microorganisms and has a water outlet, and wherein the chamber body and the filter means are in liquid communication and wherein water inters the chamber body through the water inlet and flows from the chamber body through the filter means and out through the water outlet. The above described embodiments with respect to the device of the present invention apply also to the device for use in the method as described above.

DRAWINGS

The invention will now be described more fully with reference to the appended drawings illustrating typical embodiments of the new water disinfection device.

Figure 1 illustrates a water disinfection device unit (1-12) wherein the water to be disinfected is led into the system via the water inlet (1). Softened, well filtered water may elongate the service interval but alternatively, the system should be cleaned as required. In a chamber body (2), two electrode plates (3, 4) are placed in parallel and symmetrically arranged and having a suitable distance, such as from 1-5 mm, wherein each pair is fitted with a fuse (not shown), wherein a suitable current density is applied, and wherein the plates are made of a conductive material and are arranged in a perpendicular plane to produce the disinfectant. As to prevent scaling of the electrodes a device (5) that reverses the polarity is connected to the electrodes (3, 4) via a conduit (11, 12) and thus may be used to switch the direction of the current and reverse the scaling process. A power source (6), such as a commercially available LED driver capable of constant current mode, drives the disinfection process and is connected to the device (5) via a conduit (10). The water with the freshly produced disinfectant passes the membrane (7), where the microorganisms are trapped and subjected to a constant high disinfectant concentration. An optional flow switch (8), which can serve to activate the disinfection process, may be fitted just downstream from the filter (7), thus ensuring that the electrode plates (3, 4) only power on when the chamber (2) is filled with water. Freshly disinfected water is coming out of the outlet (9). Figure 2 illustrates a water disinfection device unit (1-20) wherein the water to be disinfected is led into the system via the water inlet (1). This further embodiment of the invention comprises an integrated pre-treatment (14), ensuring that the water is filtered by particle filters and a carbon filter, followed by an ion-exchanger that softens the water. After passing a pressure sensor (15) and a solenoid valve (16), the water flows to the disinfection chamber body (2). From the chamber body (2) the water passes through the filter (7) and is stored in the water tank (17) until delivered to the user. The pump and pressure sensor (18) ensures that the solenoid valves (not shown) only opens when water is present, so no overheating takes place. The pump controls the delivery of disinfected water to the user. The dual solenoid valve arrangement (not shown) is chosen for safety, since if a valve is closing this might lead to flooding. The chamber body (2) may be made from any suitable plastic material and contains two electrodes (3, 4) of typically, 50 x 160 mm expanded titanium covered with noble metal oxides. The electrodes (3, 4) are connected to a power supply (not shown) delivering an adjustable but constant electrical current up to 4 A. The filter (7) may be of the hollow fiber type, made from a polyether-sulphonate polymer or similar material and drops the water over an air gap into the water tank (17). A pump (18) (either with an integrated pressure sensor or with other means for controlling the on/off action) delivers the water to the outlet (9). In order to minimize noise and vibration, a vibration dampener (19) may be fitted before the outlet (9). This design allows the invention to disinfect a large range of waters as a stand-alone unit. A control unit (not shown) fill the water tank (17) by opening the valve (16), thus allowing the pump (18) to supply freshly disinfected water comming out of the outlet (9). Tests made by the applicant showed in an example a reduction in the measured concentration of Legionella Pneumophilia from 6500 pr/liter to less than 1. In another example, a reduction from 500 to less than 1 was measured. The filter (7) is made from Silicon Carbide, Titanium Oxides and Aluminium Oxide and have also been tested for this invention and would perform as well as the chosen filter. In an even further embodiment the disinfection system allow recirculation (20) of the water in the tank, thus disinfecting the water one or more further times. This design in figure 2 allows water to remain in the tank ready to use for extended periods of time.

All references, including publications, patent applications and patents, cited herein are hereby incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and was set forth in its entirety herein. All headings and sub-headings are used herein for convenience only and should not be construed as limiting the invention in any way.

Any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. Recitation of ranges of values herein are merely intended to serve as a short method of referring individually to each separate value falling within the range, unless other- wise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Unless otherwise stated, all exact values provided herein are representative of corresponding approximate values (e.g., all exact exemplary values provided with respect to a particular factor or measurement can be considered to also provide a corresponding approximate measurement, modified by "about", where appropriate).

All methods described herein can be performed in any suitable order unless other- wise indicated herein or otherwise clearly contradicted by context.

The terms "a" and "an" and "the" and similar referents as used in the context of de-scribing the invention are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Thus, "a" and "an" and "the" may mean at least one, or one or more.

The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise indicated. No language in the specification should be construed as indicating any element is essential to the practice of the invention unless as much is explicitly stated.

The citation and incorporation of patent documents herein is done for convenience only and does not reflect any view of the validity, patentability and/or enforceability of such patent documents. The description herein of any aspect or embodiment of the invention using terms such as

"comprising", "having", "including" or "containing" with reference to an element or elements is intended to provide support for a similar aspect or embodiment of the invention that "consists of, "consists essentially of, or "substantially comprises" that particular element or elements, unless otherwise stated or clearly contradicted by context (e.g., a composition described herein as comprising a particular element should be understood as also describing a composition consisting of that element, unless otherwise stated or clearly contradicted by context).

This invention includes all modifications and equivalents of the subject matter re-cited in the aspects or claims presented herein to the maximum extent permitted by applicable law. The features disclosed in the foregoing description may, both separately and in any combination thereof, be material for realizing the invention in diverse forms thereof.

The in detail described model below is the preferred embodiment, but it is obvious to the skilled engineer that other disinfection methods such as ozonation, free radical generation etc. also will work in conjunction with the membrane. DESCRIPTION OF THE PREFERRED ELECTROCHEMICAL DISINFECTION METHOD

An electro chlorination chamber is composed of an area where electrodes are in liquid (close) contact with each other. When performing electro chlorination, electrical power is applied to the electrodes. Those receiving a positive electrical potential are known as anodes, and those receiving a negative potential as cathodes. Due to the electrical energy passing through the electrolyte (water) electrode reactions are taking place as follow:

At the anode water is oxidized electrochemically - leaving oxygen and protons. Also at the anode chloride ions (CI ) naturally contained in the water donate electrons to the cathode and become chlorine gas (C¾). The chlorine gas dissolves in the acidic water and it is converted to hypochlorous acid (HCIO) and chloride ions (CI ) when the local pH is low enough.

At the cathode water is reduced - leaving hydrogen gas and hydroxyl ions. The environment of the cathode thus reaches a rather high pH. At a certain level the pH is high enough to lead to precipitation of CaC0₃ and Mg(OH)₂

The bacteria are killed when they are traversing the alternating, locally isolated regions of interchanging low and high pH, combined with the toxic effect of the oxidized chlorine species. The anode according to the present invention produces both chlorine-based and oxygen-based oxidants. The involved electrochemical and chemical reactions are outlined below.

Oxidation of water:

H₂0 → 2H⁺ + ½0₂ + 2e Electrochemical oxidation of chloride:

2Cr→Cl₂ + 2e

Dissolution of chlorine gas, chemical disproportionation, acid/base equilibrium reactions:

Cl₂ + H₂0→ HCIO + H⁺ + cr HCIO <-> CIO^" + H⁺

Other oxidation processes:

2H₂0→ H₂0₂ + 2H⁺ + 2e^~ H₂0→OH* + H⁺ + e^"

OH*→0* + H⁺ + e^"

Reaction of anode activated surface species:

0₂ + O*→ 0₃

20H*→ H₂0₂

Reduction of water:

2H₂0 + 2e^~→ H₂ + 2OH- Other reduction processes

0₂ + 2H₂0 + 2e^"→ H₂0₂ + 20H^"

The chlorine based oxidants formed at the anode have different biocidal strengths, where CI₂ is most poisonous, followed by HCIO and then CIO^" as reported in: "Handbook of Chlorination and Alternative Disinfectants ", White, C, John Wiley & Sons, New York. USA, (1999). HCIO is reported to be in excess of 100 times more effective than CIO. The invented system maintains low inherent pH values at the anode thus securing a high local concentration of HCIO as compared to neutral water having a pH value around 7. The arrangement of the electrodes and the established fit of the stack in the chamber ensure that all water will pass close to an anode during the treatment - likely several times during passage of the chamber. The electrodes are perforated to ensure that the water can shift horizontally during the ascent of the chamber.

Claims

We claim:

1. A water disinfection device comprising a chamber body for disinfection of water and a filter means, wherein the chamber body comprises means for providing a disinfectant from the water or air in the chamber body and has a water inlet, wherein the filter means is substantially impermeable to microorganisms and has a water outlet, and wherein the chamber body and the filter means are in liquid communication and wherein water inters the chamber body through the water inlet and flows from the chamber body through the filter means and out through the water outlet.

2. The device of claim 1, wherein the water to be disinfected contain at least 2 ppm, such as at least 5 ppm, such as at least 7 ppm, e.g. at least 10 ppm of chloride ions.

3. The device of claim 2, wherein the water to be disinfected has an electrical conductivity of at least 20μ8/αη, such as at least 50μ8/α , e.g. at least ΙΟΟμΞ/αη.

4. The device of any one of claims 2-3 wherein the chloride ion content comes from natural sources and/or is added to the water before disinfection.

5. The device of any one of claims 1-4 wherein the filter means is an integrated part of the chamber body or is separate from the chamber body.

6. The device of any one of claims 1-5 wherein the filter means, such as a membrane, is made of a material that does not degrade in the presence of an oxidizing disinfectant, such as chlorine.

7. The device of claim 6 wherein the oxidizing disinfectant is selected from chlorine, ozone, peroxides, and/or free radicals.

8. The device of any one of claims 1-7 wherein the filter means is made of a polymer material which does not degrade in the presence of an oxidizing disinfectant.

9. The device of claim 8 wherein the polymer material is selected from a fluorinated hydrocarbon polymer or a poly ether- sulfonic polymer.

10. The device of any one of claims 1-9 wherein the filter means comprises a ceramic material selected from any one of Diatomite, Silicon Carbide, Alumina Oxide, Titanium Oxide, Zirconium Oxide, stabilized Zirconium Oxide, or mixtures thereof, or mixtures where the major component thereof is one of Silicon Carbide, Alumina Oxide, Titanium Oxide, Zirconium Oxide, or stabilized Zirconium Oxide,.

11. The device of any one of claims 1-10 wherein the disinfectant provided is selected from chlorine, ozone, peroxides, and/or free radicals.

12. The device of any one of claims 1-11 wherein the means for providing the disinfectant is two or more pair of electrodes capable of converting the water and/or the salts therein to disinfectants.

13. The device of any one of claims 1-12 wherein the water has been softened before entering the water inlet.

14. The device of any one of claims 1-13 wherein a pre-filter has been provided before the water inters the water inlet.

15. The device of any one of claims 1-14 wherein no chemicals are added to the water during or after disinfection.

16. The device of any one of claims 1-15 wherein the means for providing the disinfectant comprises a pair of parallel and symmetrically arranged perforated electrode plates having a suitable distance, wherein a suitable current density is applied, and wherein the plates are made of a conductive material and are arranged in a perpendicular plane.

17. The device of claim 16 wherein the pair of parallel and symmetrically arranged perforated electrode plates have a distance selected from 1-5 mm.

18. The device of claim 16 or 17 wherein the current density is above 5 mA/ cm².

19. The device of any one of claims 16-18 wherein the polarity of the electrodes can be reversed.

20. The device of any one of claims 1-19 wherein a water tank is provided after the filter means before the water outlet.

21. The device of claim 20 wherein a pump means is provided after the water tank before the water outlet.

22. The device of claim 20 wherein a pump and/or pressure means is provided after the water tank before the water outlet.

23. A method of producing disinfected water for consumption comprising leading water to be disinfected through a water disinfection device of any one of claims 1-22.