BACKGROUND OF THE INVENTION

Water is arguably mankind's most precious commodity. Without it, human will cease to exist. Because water is such an essential component of life, governments all over the world make major efforts to provide clean potable drinking water for their citizens.

Water supply systems get water from a variety of locations, including groundwater (aquifers), surface water (lakes and rivers), and the sea through desalination. After appropriate treatment, the water is supplied to users.

Water treatment steps include, in most cases, purification, disinfection through chlorination, ozonation and sometimes fluoridation. Treated water then either flows by gravity or is pumped to reservoirs, which can be elevated, such as water towers, or on the ground. Then the water is distributed to consumers through pipe networks. Once water is used, the wastewater is typically discharged to a sewer system and treated in a sewage treatment plant before being discharged into a river, lake or the sea or reused for landscaping, irrigation or industrial use.

A major problem is that infrastructure to distribute water is often aging and poorly maintained and is therefore susceptible to breaks and leaks in the piping. If distribution systems are damaged, water can be contaminated with waterborne disease organisms.

In many places, sewer pipes are worn out, lack sufficient capacity to absorb sewage or both. Many leak and, since sewer pipes and fresh water pipes are often in close proximity, the leakage can enter the fresh water pipes, contaminating the fresh water with bacteria, viruses, nitrates, detergents, oils, and chemicals. Other typical contaminants that can enter fresh water piping include: cooking, heating and motor oils, lawn and garden chemicals, paints and paint thinners, disinfectants, medicines, photographic chemicals, industrial chemicals, swimming pool chemicals, and pesticides. Therefore, in many places, tap water is contaminated. In some places, water supplied to consumers is taken directly from wells or rivers with minimum purification. Such places often lack adequate purification, with many lacking even sewage purification, so that both well water and river water can be contaminated. Thus, bacterial contamination of water continues to be a widespread problem across the world and is a major cause of illness and deaths of millions affected by waterborne diseases annually. The major pathogenic organisms responsible for water borne diseases are bacteria (E Coli, Shigella, V cholera), viruses (Hepatitis A, poliovirus, rotavirus) and parasites (E histolytica, Giardia, hookworm). Thus is it essential to provide a system that can purify water and provide pure water to the entire house.

Household point of use (POU) and point of entry (POE) treatment devices rely on many of the same treatment technologies that have been used in central treatment plants such as irradiation with ultraviolet light (UV), reverse osmosis (RO), filtration and chlorine treatment.

However, while central treatment plants treat all water distributed to consumers identically, POU and POE treatment devices treat only a portion of the total flow. POU devices treat only water intended for direct consumption (drinking and cooking), typically at a single tap or a limited number of taps, while POE treatment devices typically treat all the water entering a single facility, such as house, business, school, or apartment building.

The limitation of RO, UV and filtration in a point of entry system is that, since the process does not provide any residual to protect water quality in the facility's distribution system, contamination can re-enter the water before it is used.

Furthermore, RO systems requires high pressure pumps that consume a lot of energy and RO systems can have a very low flow rate.

The limitations of chlorine treatment systems are that the chlorine can have toxic effects, it badly affects the taste and odor of the water, and it does not inactivate all pathogens. For example, Cryptosporidium cysts are unaffected by chlorine.

Another problem in prior art POU and POE systems is that they require constant maintenance. If not properly maintained, these systems can contaminate the tap water instead of purifying it.

Ozone is a very powerful gaseous reactant and its usefulness has been well established for many years in a wide range of industrial applications. Recently its value in all types of water purification applications has been coming to the fore because of its ability to act as a powerful oxidant, microflocculant and disinfectant without producing toxic side products. Not only can ozone kill bacteria, viruses and cysts in the water 3000 times faster than chlorine, but it also improves the taste and odor of the water, and oxidizes organics and metals in the water. For example, ozone can convert Arsenic III to Arsenic V, which is not only is 60 times less toxic than Arsenic III, but can also be easily adsorption united.

Ozone can significantly reduce the number of harsh chemicals such as chlorine that may be needed as a residual and, since organics are removed by the ozone, the amount of their byproducts, suspected to be carcinogens, is even further reduced.

Another advantage of ozone over chlorine is that ozone is less corrosive than chlorine in water, thus reducing damage to the pipes and enabling them to stay in good condition for longer.

In ozone-based systems, disinfection efficiency depends on the CT value, which is given by

CT value (mg*min/l) = Contact time (min) * dissolved ozone Concentration (mg/1).

In order to achieve a sufficiently high CT value, one high enough to ensure a desired level of purification of the water, most prior art systems use a contact tank, which increases both the footprint of the system and its cost.

Therefore, there is a long-felt need to provide a point of entry water purification system, which can eliminate substantially all pathogens and reduce harmful metals, does not require an external power source and does not reduce the flow rate of water passing through it.

SUMMARY OF THE INVENTION

It is an object of the present invention to disclose a system for providing a compact inline water purification system installable at the point of entry of water to a facility which does not require an external power source, which is connectable to a municipal water supply at the point of entry to a facility, and which can provide the entire facility with purified water, substantially free of pathogens and with significantly reduced levels of heavy metals.

It is another object of the present invention to provide a compact inline water purification system, wherein said compact inline water purification system comprises: a power source; a gas supply mechanism selected from a group consisting of: an air dryer configured to dry gas passing therethrough, an oxygen concentrator and any combination thereof; a cold plasma ozone generator configured to generate ozone, power for said cold plasma ozone generator providable by said power source; at least one mixing mechanism downstream of said cold plasma ozone generator, said mixing mechanism configured to input a member of a group consisting of: an output from said cold plasma ozone generator, water, and any combination thereof and to output a mixture of said output from said cold plasma ozone generator and said water; wherein said power source is selected from a group consisting of: an inline hydroelectric generator, a solar panel, a source of mains current, a battery, an external power generator and any combination thereof.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said cold plasma ozone generator comprises: an inlet gas port in fluid communication with said gas supply mechanism; at least one in-electrode, said in-electrode having a plurality of perimeter holes substantially at a perimeter of the same; said plurality of perimeter holes are in fluid communication with said inlet gas port, said plurality of perimeter holes configured to allow said dry gas to pass therethrough; at least one out-electrode, said out-electrode having at least one hole at the center of the same, said at least one hole configured to allow gas to pass therethrough; said in-electrode and said out-electrode configured to maintain said high voltage AC therebetween; at least one spacer between said in-electrode and said out-electrode, said spacer configured to maintain a constant-width gap between said in-electrode and said out-electrode, said constant- width gap configured to allow said gas to pass from said plurality of perimeter holes in said in-electrode to said at least one hole in said out-electrode; and an outlet port in fluid communication with said at least one hole in said out-electrode.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein a thickness of said gap is in a range between about 0.1 mm and about 0.5 mm.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein a thickness of said gap is about 0.3 mm. It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said radially inward passage of said gas from said plurality of perimeter holes to said at least one central hole is configured to provide that said gas contacts substantially all of an area in said gap between said electrodes (1, 2) so as to maximize an amount of ozone in said gas.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, additionally comprising at least one sensor in fluid communication with said outlet port of said at least one mixing mechanism, said at least one sensor configured to measure at least one parameter related to concentration of ozone in water;

It is another object of the present invention to provide the compact inline water purification system as disclosed above, additionally comprising at least one microprocessor in communication with said at least one sensor, said microprocessor configured to determine, from said measured at least one parameter, concentration of ozone in said water and to compare said concentration of ozone with a predetermined minimum.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, additionally comprising at least one alert mechanism configured to provide an alert if said concentration of ozone is below said predetermined minimum.

It is another object of the present invention to provide the method as disclosed above, wherein substantially all pathogens in said water are killed by said ozone.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said compact inline water purification system is connectable to a water supply, pressure providable by said water supply forcing water through said compact inline water purification system.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, additionally comprising at least one purifier unit.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said purifier unit comprises at least one adsorption unit.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said adsorption unit comprises a member of a group consisting of: non-woven fiber, woven fiber, alumina, fiber in a matrix, silver, zinc, pseudoboehmite, carbon, zeolite, cellulose, polyester, cotton, nylon, and any combination thereof.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said adsorption unit is configured to remove a member of a group consisting of: endotoxins, toxins, viruses, bacteria, cysts, volatile organic compounds, polysaccharides, colloids, particulates, trace pharmaceuticals, heavy metals, bromate, chlorine, mud, sand and turbidity.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said mixing mechanism is selected from a group consisting of: a venturi injector, a flash reactor, a static mixer and any combination thereof.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said mixing mechanism is configured to output an equilibrium mixture of ozonated gas and water.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, additionally comprising a valve configured to control a fraction of said water passing through said at least one mixing mechanism.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said gas is selected from a group consisting of atmospheric air, oxygen and any combination thereof.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, additionally comprising at least one second sensor, said at least one second sensor configured to measure a member of a group consisting of: input flow rate, output flow rate, input water pressure, output water pressure, AC voltage, DC voltage and any combination thereof.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said at least one microprocessor is additionally configured to provide an alert under a condition selected from a group consisting of: input flow rate too low, input flow rate too high, output flow rate too low, output flow rate too high, input pressure too low, input pressure rate too high, output pressure too low, output pressure too high, difference between input pressure and output pressure too high, AC voltage too low, AC voltage too high, DC voltage too low, DC voltage too high, and any combination thereof. It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said water supply is selected from a group consisting of a municipal water supply, a regional water supply, a local water supply and any combination thereof.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said turbidity is removable from said water by said water supply.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said s compact inline water purification system is configured to purify all water entering a facility.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein all water entering said facility is from a single source, said source connected to said water supply.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said facility is selected from a group consisting of: a portion of an edifice, an edifice and a limited number of edifices.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said facility is selected from a group consisting of: a house, a business, a school, and an apartment building

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said at least one spacer is a single spacer.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein each said electrode is in communication with a PCB, said PCB configured to supply said high-voltage AC to said electrode.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said communication is by means of at least one spring- loaded contact.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said spring-loaded contact is configured to maintain good electrical contact between at least one electrode pad on said PCB and at least one member of a group consisting of said in-electrode and said out-electrode. It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said electrode is replaceable without need to replace said PCB.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said PCB is replaceable without need to replace said electrode.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein each said electrode comprises stainless steel.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein each said electrode comprises a ceramic dielectric coating.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said coating is a multilayer coating.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said coating has a thickness in a range from about 75 μιη to about 125 μιη.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said coating is applicable by means of deposition of a precursor on said stainless steel electrode by means of a screen printing process.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said precursor is curable by: (i) said electrode comprising said precursor being in a drying oven at 150 degrees C for a few minutes; (ii) said electrode comprising said precursor being heated to 900 degrees C at a predetermined rate; (iii) said electrode comprising said precursor being at said 900 degrees C for approximately 15 minutes; and (iv) said electrode comprising said precursor being cooled at a predetermined rate.

It is another object of the present invention to provide a method of purifying water for use in a facility comprising steps of: providing a compact inline water purification system comprising: a power source; a gas supply mechanism selected from a group consisting of: an air dryer configured to dry gas passing therethrough, an oxygen concentrator and any combination thereof; a cold plasma ozone generator to generate ozone, power for said cold plasma ozone generator providable by said power source; at least one mixing mechanism downstream of said cold plasma ozone generator, said mixing mechanism configured to input a member of a group consisting of: an output from said cold plasma ozone generator, water, and any combination thereof and to output a mixture of said output from said cold plasma ozone generator and said water; connecting an input of said compact inline water purification system to a water supply; connecting an output of said compact inline water purification system to an input of a facility's water supply; at such times as said water supply provides water under pressure, operating said compact inline water purification system; wherein said power source is selected from a group consisting of: an inline hydroelectric generator, a solar panel, a source of mains current, a battery, an external power generator and any combination thereof.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of providing said cold plasma ozone generator with: an inlet gas port in fluid communication with said gas supply mechanism; at least one in-electrode, said in-electrode having a plurality of perimeter holes substantially at a perimeter of the same, said plurality of perimeter holes in fluid communication with said inlet gas port, said plurality of perimeter holes configured to allow said dry gas to pass therethrough; at least one out-electrode, said out-electrode having at least one hole at the center of the same, said at least one hole configured to allow gas to pass therethrough, said in-electrode and said out-electrode configured to maintain said high voltage AC therebetween; at least one spacer between said in-electrode and said out-electrode, said spacer configured to maintain a constant-width gap between said in-electrode and said out-electrode, said constant- width gap configured to allow said gas to pass from said plurality of perimeter holes in said in-electrode to said at least one hole in said out-electrode; and an outlet port in fluid communication with said at least one hole in said out-electrode.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting a thickness of said gap to be in a range between about 0.1 mm and about 0.5 mm.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting a thickness of said gap to be about 0.3 mm.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing, by means of said radially inward passage of said gas from said plurality of perimeter holes to said at least one central hole, that said gas contacts substantially all of an area in said gap between said electrodes (1, 2), thereby maximizing an amount of ozone in said gas.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing at least one sensor in fluid communication with said outlet port of said at least one mixing mechanism, said at least one sensor configured to measure at least one parameter related to concentration of ozone in water;

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of measuring said concentration of ozone in said water output from said cold plasma ozone generator;

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing at least one microprocessor in communication with said at least one sensor, said microprocessor configured to determine, from said measured at least one parameter, concentration of ozone in water output from said cold plasma ozone generator and to compare said concentration of ozone with a predetermined minimum.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of providing at least one alert mechanism; and, at such times as said concentration of ozone is below said predetermined minimum, providing an alert.

It is another object of the present invention to provide the method as disclosed above, wherein substantially all pathogens are removed from said water by said ozone. It is another object of the present invention to provide the method as disclosed above, wherein, by means of pressure provided by said water supply, forcing water through said compact inline water purification system.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing at least one purifier unit.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing said purifier unit with at least one adsorption unit.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting a material of said at least one adsorption unit to be a member of a group consisting of: non-woven fiber, woven fiber, alumina, fiber in a matrix, silver, zinc, pseudoboehmite, carbon, zeolite, cellulose, polyester, cotton, nylon, and any combination thereof.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of removing, by means of said at least one adsorption unit, a member of a group consisting of: endotoxins, toxins, viruses, bacteria, cysts, volatile organic compounds, polysaccharides, colloids, particulates, trace pharmaceuticals, heavy metals, bromate, chlorine, mud, sand and turbidity.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting said mixing mechanism from a group consisting of: a venturi injector, a flash reactor, a static mixer and any combination thereof

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of outputting from said member of said mixer group an equilibrium mixture of ozonated gas and water.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of providing a valve and of controlling, by means of said valve, a fraction of said water passing through said at least one mixing mechanism.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting said gas from a group consisting of atmospheric air, oxygen and any combination thereof.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of providing at least one second sensor, and of measuring, by means of said at least one second sensor, a member of a group consisting of: input flow rate, output flow rate, input water pressure, output water pressure, AC voltage, DC voltage and any combination thereof.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing, by means of said at least one microprocessor, an alert under a condition selected from a group consisting of: input flow rate too low, input flow rate too high, output flow rate too low, output flow rate too high, input pressure too low, input pressure rate too high, output pressure too low, output pressure too high, difference between input pressure and output pressure too high, AC voltage too low, AC voltage too high, DC voltage too low, DC voltage too high, and any combination thereof.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting said water supply from a group consisting of a municipal water supply, a regional water supply, a local water supply and any combination thereof.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting, for said water supply, a water supply which has removed turbidity from said water.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of purifying, by means of said compact inline water purification system, all water entering a facility.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing all water entering said facility from a single source, said source connected to said water supply.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting said facility from a group consisting of: a portion of an edifice, an edifice and a limited number of edifices.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting said facility from a group consisting of: a house, a business, a school, and an apartment building. It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing said at least one spacer as a single spacer.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing each said electrode in mechanical communication with a PCB, said PCB configured to supply said high-voltage AC to said electrode.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of providing said mechanical communication by means of at least one spring-loaded contact, and of maintaining, by means of said spring-loaded contact, good electrical contact between at least one electrode pad on said PCB and at least one member of a group consisting of said in-electrode and said out-electrode.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of replacing said electrode without replacing said PCB.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of replacing said PCB without replacing said electrode.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting each said electrode to comprise stainless steel.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of providing each said electrode with a ceramic dielectric coating.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting said coating to be a multilayer coating.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of selecting said coating thickness to be in a range from about 75 μηι to about 125 μιη.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of applying said coating by screen printing a precursor onto said stainless steel electrode.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of curing said precursor by: (i) placing said electrode comprising said precursor in a drying oven at 150 degrees C for a few minutes; (ii) heating said electrode comprising said precursor to 900 degrees C at a predetermined rate; (iii) maintaining said electrode comprising said precursor at said 900 degrees C for approximately 15 minutes; and (iv) cooling said electrode comprising said precursor at a predetermined rate.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said power source powers said air dryer.

It is another object of the present invention to provide the compact inline water purification system as disclosed above, wherein said air dryer is powered by a second power source, said second power source selected from a group consisting of: an inline hydroelectric generator, a solar panel, a source of mains current, a battery, an external power generator and any combination thereof.

It is another object of the present invention to provide the method as disclosed above, additionally comprising a step of powering said air dryer by said power source.

It is another object of the present invention to provide the method as disclosed above, additionally comprising steps of powering said air dryer by a second power source and of selecting said second power source from a group consisting of: an inline hydroelectric generator, a solar panel, a source of mains current, a battery, an external power generator and any combination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. la-c illustrates typical locations for installation of the water purification system;

Fig. 2 schematically illustrates the structure of the water purification system in use;

Fig. 3 schematically illustrates water flow in an embodiment of the disinfector of the present invention;

Fig. 4a is a perspective view of an embodiment of the cold plasma ozone generator of the present invention;

Fig. 4b is a side elevation cross-sectional view of an embodiment of the cold plasma reactor cell;

Fig. 4c is a perspective view of another embodiment of the cold plasma ozone generator of the present invention;

Fig. 4d is a side elevation cross-sectional view of another embodiment of the cold plasma reactor cell; Fig. 4e shows an exploded view of the embodiment of the cold plasma ozone generator of the present invention;

Fig. 5a illustrates gas flow inside the cold plasma ozone generator cell;

Fig. 6 illustrates liquid flow in an embodiment, which combines a venturi injector and a decontaminator/static mixer;

Fig. 7 illustrates an embodiment of a purifier in which water is driven through an adsorption unit by water pressure;

Fig. 8a-c illustrates an embodiment of a screen-printing process for laying down the precursor layers to form a dielectric coating on a stainless steel electrode; and

Fig. 9a-b schematically illustrates water sampling points for an analysis of the effectiveness of the system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following description is provided, alongside all chapters of the present invention, so as to enable any person skilled in the art to make use of said invention and sets forth the best modes contemplated by the inventor of carrying out this invention. Various modifications, however, will remain apparent to those skilled in the art, since the generic principles of the present invention have been defined specifically to provide a means and method for providing pure water to all the taps in a building.

The term 'facility' hereinafter refers to a portion of an edifice, an edifice or a limited number of edifices supplied with water from a single source. Typically, the source is a pipe connected to a municipal water supply system. Non-limiting examples of a facility include a house, a business, a school, and an apartment building.

The term 'about' hereinafter refers to a range of plus or minus 25% around the nominal value. If a range of values is given, the extreme limits of the range therefore become (75% of the minimum of the range) to (125% of the maximum of the range).

The present invention provides a compact inline water purification system connectable to a municipal water supply which can be directly connected to the inlet water pipe of a facility such as house, business, school, or apartment building at the point of entry (POE) of the water to the facility, either as part of a new facility or retrofitted to the water supply of an existing facility. The present invention can provide a true water "firewall" which inactivates over 99.9999% of microbiological and metal contaminations, and does not require an external power source and can provide an entire facility with purified water, substantially free of pathogens and with significantly reduced levels of heavy metals.

The water purification system of the present invention includes a hydroelectric generator that generates sufficient electric power to run the purifier. This hydroelectric generator forms part of the inlet gas port of the purifier, which is connected to the municipal authority's distribution water pipe. Therefore, the present invention does not require additional power and is independent of the electric grid.

The current invention uses the pressurized water supplied by the municipality to inject the ozone generated by the invention into the water, thus eliminating the need for an external pump, thus reducing the complexity of the system, which reduces both the cost of manufacture and the cost of operation.

Fig. la-c illustrates typical locations for installation of the water purification system.

Fig. la illustrates an embodiment of the water purification system installed in an apartment building. The disinfector (300) is installed in the roof of the building (200), upstream of the inlet to the main building storage tank(s). The purifier(s) (400) are installed downstream of the storage tank(s). The purifier(s) (400) can be at any position downstream of the main storage tank(s); preferably, a purifier (400) is installed at the point of entry of the water to each individual unit in the building. In the non-limiting example shown, the purifiers (400) are immediately upstream of the water meters for the units.

Fig. lb-c illustrate two embodiments of the water purification system as installed in a private house.

In the embodiment of Fig. lb, the disinfector (300) is installed in the roof of the house (200), upstream of the inlet to the main storage tank, and the purifier (400) is installed in the roof of the house, immediately downstream of the main storage tank.

In Fig. lc, the disinfector (300) and the purifier (400) are installed immediately downstream of the domestic water meter.

Fig. 2 schematically illustrates the structure of the water purification system in use. The water (black arrows) enters the building (200), passes through the disinfector (300), passes through the purifier (400) and, from there, is distributed to the household taps (dashed arrows).

Disinfector

The disinfector (200) includes a high-efficiency cold plasma ozone generator that does not require any electrode cooling.

In some embodiments, the cold plasma ozone generator of the present invention uses dry air or oxygen-enriched air as a feed gas so it includes an air dryer to dry the air supplied to the ozone generator. The air dryer can be any conventional air dryer known in the art, preferably one configured for supplying dry air to an ozone generator. Using dry air increases the yield of the ozone generator and eliminates unwanted arcing and production of nitric acid.

In some embodiments, the cold plasma ozone generator uses oxygen-enriched air from an oxygen concentrator. The oxygen concentrator can be used alone, or in conjunction with an air dryer. Power for the air dryer can be supplied by the same source as powers the ozone generator, or the air dryer can use a separate power source, which can be selected from a group consisting of: an inline hydroelectric generator, a solar panel, a source of mains current, a battery, an external power generator and any combination thereof.

The present invention provides improved ozone injection because the ozone is injected into the water through a mixing mechanism such as a venturi injector manifold, a flash reactor, a static mixer and any combination thereof. Transfer of ozone to the pressurized water can be significantly improved by use of a combined venturi injector manifold and a flash reactor, which can also provide a homogeneous mixture of water and ozone.

In order to ensure proper ozonation, preferred embodiments of the present invention include an inline ozone sensor, typically a dissolved ozone sensor or an oxidation -reduction potential (ORP) sensor. The first provides a direct method of measuring the amount of ozone dissolved in the water, while the second one uses an indirect method but is much less expensive. The sensor ensures that the water flowing from the outlet port of the disinfector contains enough dissolved ozone to disinfect the water and inactivate the pathogens therein, according to World Health organization (WHO) and US Environmental Protection Agency (EPA) guidelines. To control the disinfector, the present invention includes a microprocessor in communication with at least one sensor. The sensor(s) can measure, for non-limiting example, the input flow rate, the output flow rate, the pressure, and the ozone level in the water. The processor converts the sensor signal into measured parameter level and, from the measured parameter level(s), controls the cold plasma ozone generator and provides an alert when there is a fault in the disinfector. In this way, the consumer is informed when maintenance is, or soon will be, necessary, thus minimizing the amount of maintenance while ensuring that the water remains pure.

As opposed to prior art ozone disinfection systems, the present invention do not need a built- in contact tank, since it uses existing infrastructure such as the distribution pipes or domestic water tanks as a contact tank. Thus, the needed contact time to achieve high quality water can be provided without the requirement for a system contact tank, which reduces the cost and complexity of the system.

Since the disinfector requires neither a pump nor a contact tank, it can be very compact and it can easily be connected inline to the city water pipe at the entry to a building.

A disinfector the above structure, in conjunction with a purifier to prevent recurrence of pathogens in the water and to remove mud, sand and turbidity, can provide potable drinking water free of pathogens for all taps in a building without the need for an external source of electricity, and without a need for regular maintenance.

Fig. 3 schematically illustrates water flow in an embodiment of the disinfector of the present invention.

Pressurized water, which may be contaminated, flows from the main city pipe through the inlet gas port of the disinfector and into a hydroelectric generator (1). The hydroelectric generator (1) provides power for the microprocessor that runs the system and activates the cold plasma ozone generator, so that the disinfector will only be activated and ozone will only be generated when there is water flow.

After exiting the hydroelectric generator, the water comes to T-junction, which separates the water into a lower loop and an upper loop. Water flows into the lower loop through a ball valve (6) and then reaches another T-junction. The fraction of the flow entering the lower loop depends on the ball valve (6) - the more the ball valve is opened, the greater the fraction of the incoming water in the lower loop. If the ball valve is closed, all the water flows into the upper loop and through the mixing mechanism which is, in this embodiment, a venturi injector (5), while if the ball valve is fully open, all the water flows into the lower loop, avoiding the venturi injector. Thus, the ball valve (6) controls the amount of water flowing into the venturi injector (5). Water flowing through the venturi injector (5) creates a vacuum that generates the suction that draws the air from the air dryer (2) or oxygen concentrator.

When pressurized water enters the venturi injector (5) inlet, it is constricted toward the injection chamber and changes into a high-velocity jet stream. This increase in velocity through the injection chamber results in a decrease in absolute pressure, creating a vacuum, thereby enabling ozone gas to be drawn through the suction port and entrained into the water stream. As the jet stream is diffused toward the injector outlet, its velocity is reduced and it is reconverted into a lower pressure flow.

When vacuum is generated by the flow of the water inside the venturi injector (5), it generates air flow from the air dryer (2) or oxygen concentrator to the cold plasma ozone generator (13). Since the more moisture in the air, the lower the ozone output, the air is dried in an air dryer (24) before it enters the cold plasma ozone generator. For ambient air with a maximum relative humidity of 90%, a preferred embodiment of an air dryer can produce air with a relative humidity less than 5% at an air flow rate of 0.5 - 4 1/min.

Since the air entering the cold plasma ozone generator is dry, the air that will be injected into the contaminated water will contain large quantities of ozone.

Figs. 4a and 4b show an embodiment of the cold plasma ozone generator of the present invention.

Fig. 4a is a perspective view of the embodiment. This view illustrates the enclosures (6) for the electrodes, the PCB electrode with its conductive pad (4), the two 90 degree ozone resistant fittings forming the inlet gas port (10) and the outlet gas plus ozone port (20), and the screws (9) that fasten an electrode enclosure (6), a PCB electrode (4) and a PCB spacer (11) to the main high voltage AC power supply PCB (3). The conductive electrodes with a non-porous dielectric coating and the sealing components are not visible in this view.

Fig. 4b is a side cross-sectional view of the embodiment of Fig. 4a

The electrodes (1, 2) are preferably plates of stainless steel coated with ceramic dielectric material, and are preferably of the same size and shape and have the same non-porous ceramic dielectric coating. They can be generally circular, oval or elliptical, it can form a rounded rectangle, and any combination thereof, as long as all conductive edges are rounded to reduce non-linear high voltage field effects which can lead to parasitic corona and arcing. The in-electrode (1) has a plurality of holes in the perimeter, so that gas from the inlet fitting (10) flows downward and outward to the perimeter of the in-electrode, through the perimeter holes, and then radially inward from the perimeter of the gap to its center.

The out-electrode (2) has at least one hole, and preferably a single hole, in the center, so that gas flows directly from the out-electrode to the outlet gas port (20).

The PCB spacer (11) design provides accurate spacing and accurate parallelism between the in- and out- electrodes (1, 2), resulting an accurate, and uniform plasma gap between the generally flat central portions of the faces of the in-electrode (1) and the out-electrode (2).

The thickness of the plasma gap is dependent on the thickness of the non-porous ceramic dielectric coating, thickness of the main PCB (3), PCB spacer (11), PCB electrode (4) and on the geometry of the in- and out- electrodes (1, 2). In a preferred embodiment, the gap is about 0.3 mm. It can range from about 0.1 mm to about 0.5 mm.

Since the cell is sealed, the gas cannot leak from the cell. The electrodes are sealed externally by enclosure O-ring (5), forming a perimeter seal with the main PCB (3) and the PCB electrode (4). Preferably, the O-ring (5) is made of non-conductive ozone-resistant material such as silicone, PVDF or PTFE, while the plasma gap is sealed by a Teflon O-ring (8) that seals the gaps and prevents ozone from leaking and damaging the PCB's. Another important seal is the electrode O-ring (7) which prevents ozone from escaping from the cell and damaging other components like electrode enclosure (6) and the PCB's.

This sealing technology provides secure hermetic sealing that prevents leaks of both feed gas and ozone. Therefore, this design enables use of less-expensive non ozone-resistant material for the electrode enclosures (6), PCB spacer (11), and the PCB electrode (4). This also allows the option of assembling the cold plasma reactor on the main high voltage AC power supply PCB (3).

Unlike prior art ozone generators, the cell is an integral part of the high voltage AC power supply PCB (3), rather than being separate from it. This allows the lines that provide high voltage to the electrodes to be internal connections within the main PCB (3), rather than being external wired connections. This increases the safety of the cold plasma ozone generator, makes approval for safety (such as UL or CE approval) less difficult, and reduces both assembly time and the cost of assembly. Figs. 4c-e show another embodiment of the cold plasma ozone generator of the present invention. Part numbers are different between the embodiment of Figs. 4a and 4b and the embodiment of Figs. 4c-e.

Fig. 4c is a perspective view of the embodiment. This view illustrates the enclosures (4, 5) for the electrodes (3, 2, not shown), the two 90 degree ozone resistant fittings forming the inlet gas port (8) and the outlet gas plus ozone port (18), and the screws (10) that fasten together the electrode enclosures (4, 5) and the electrode spacer (1). Also shown is the spring mechanism (25) which ensures good contact between the electrodes and the PCB

Fig. 4d is a side cross-sectional view of the embodiment of Fig. 4c

The electrodes (2, 3) are preferably plates of stainless steel coated with ceramic dielectric material, and are preferably of the same size and shape and have the same non-porous ceramic dielectric coating. They can be generally circular, oval or elliptical, it can form a rounded rectangle, and any combination thereof, as long as all conductive edges are rounded to reduce non-linear high voltage field effects which can lead to parasitic corona and arcing.

The electrode spacer (1) design provides accurate spacing and accurate parallelism between the in- and out- electrodes (2, 3), resulting an accurate, and uniform plasma gap between the generally flat central portions of the faces of the in-electrode (2) and the out-electrode (3).

The thickness of the plasma gap is dependent on the thickness of the non-porous ceramic dielectric coating, on the thickness of the electrode spacer (1), and on the geometry of the in- and out- electrodes (2, 3). In a preferred embodiment, the gap is about 0.3 mm. It can range from about 0.1 mm to about 0.5 mm.

Since the cell is sealed, the gas cannot leak from the cell. The electrodes are sealed externally by the enclosure O-rings (7), forming a perimeter seal with the enclosures (4, 5), the electrode spacer (1) and the in- (2) and out- (3) electrodes. Preferably, the O-rings (7) are made of non-conductive ozone-resistant material such as silicone, PVDF or PTFE, while the out-electrode O-ring (6) which prevents ozone from escaping from the cell and damaging other components can be made of non-conductive ozone -resistant material such as silicone, PVDF or PTFE, or can be made of Teflon.

This sealing technology provides secure hermetic sealing that prevents leaks of both feed gas and ozone. Therefore, this design enables use of less-expensive non ozone-resistant material for the electrode enclosures. In this embodiment, the PCB's and the electrodes are separately replaceable, thereby reducing the cost of repairs.

Fig. 4e shows an exploded view of the embodiment of a cold plasma ozone-generating cell of Fig. 4c.

The inlet gas port (8) is at the top, with the screws (10) below the inlet gas port (8) and the inlet enclosure (4) is between the screws (10) and the upper enclosure O-ring (7). Below the upper enclosure O-ring (7) is the in-electrode (2).

The in-electrode (2) has a plurality of holes (21) in the perimeter, so that gas from the inlet fitting (8) flows downward and outward to the perimeter of the in-electrode, through the perimeter holes, and then radially inward from the perimeter of the gap to its center.

Below the in-electrode (2) is the spacer (1), and below the spacer is the out-electrode (3). In this embodiment, the out-electrode (3) has a single hole (31) in the center, through which gas can leave the gap and enter the outlet gas port (18).

Below the out-electrode (3) is the out electrode O-ring (6), and below this, the lower enclosure O-ring (7), the outlet enclosure (5), which comprises voltage connectors to ensure that there is a good electrical connection between the voltage contacts on the PCB and the in- (2) and out- (3) electrodes, so that the high voltage is efficiently transferred from the PCB to the electrodes (2, 3).

Below the outlet enclosure (5) is the outlet gas port (18).

Fig. 5a shows the gas flow inside a cold plasma ozone generator cell. The gas feed, which is typically atmospheric air, but can be air enriched with oxygen or pure oxygen, enters through the inlet gas port (9) and passes to the center of the upper surface of the in-electrode (1). The flow then passes radially across the upper surface of the in-electrode (1) to the perimeter of in-electrode (1) (represented by black arrows) and enters the plasma gap through the holes in the perimeter of the in-electrode (1).

The gas then flows radially inward (white arrows) from the perimeter to the center of the in- (1) and out- (2) electrodes. The gas then exits from the plasma gap via the single hole in the center of the out-electrode (2) and exits the cold plasma ozone generator through the corresponding ozone outlet fitting (10).

The electrodes (1, 2) are kept at a high voltage supplied by an AC power supply (3). Since the voltage across the electrodes is uniform and the spacing between the electrodes is uniform, there will be a uniform plasma in the plasma gap. As the air flows through the plasma gap, it is subjected to repeated micro discharges, which convert some of the oxygen molecules in the air into ozone molecules. Therefore, the air flowing out of the cold plasma ozone generator will be ozone enriched.

The radial flow ensures that the air contacts substantially all of the area in the plasma gap between the electrodes (1, 2) and that the air spends sufficient time between the electrodes so as to maximize the amount of ozone in the exit gas.

This results in a very reliable and efficient ozone generator with a high and stable yield ozone. Typically, the yield is about 90 gram 0 ₃ /kWh when dry air used as the feed gas and 267 gram 0 ₃ /kWh when oxygen is used as the feed gas.

Ozonated gas from the cold plasma ozone generator (3) flows through a one-way valve that prevents back flow of water from the venturi injector (5) or other mixing mechanism to the cold plasma ozone generator (3), since water in an ozone generator can lead to destruction of the ozone generator (3).

The ozonated gas that enters a venturi injector produces thousands of bubbles, which greatly increases the surface area of ozone in contact with the water. This results in a very high mass transfer rate of ozone into the water.

From here, the ozonated water flows to a second T-junction, mixes with the water from the lower loop and flows to a flash reactor/static mixer (7) in order to achieve a homogeneous mixture of ozone and water.

In some embodiments, the flash reactor/static mixer (7) is placed in line after the ozone injector to aid in transfer of ozone into the water.

The flash reactor/static mixer (7) is a mixing chamber that incorporates a design that redirects and shears the gas/liquid water mixture in order to ensure rapid dissolution of the bubbles in the water and attainment of gas/liquid equilibrium. The result is high mass transfer efficiency with minimal time required.

The water exits the flash reactor, the static mixer or the latter of the two (7) with a predetermined minimum of concentration of ozone. For flow rates typical of household use, a concentration of ozone in the water of at least 0.5 PPM is typically sufficient to inactivate all pathogens, such as bacteria, viruses and cysts. Fig. 6 shows an embodiment which combines a venturi injector and a decontaminator. In this embodiment, the contaminated water (710) flows into a venturi injector (750) or other mixing mechanism where it is mixed with ozonated gas (790) from the cold plasma ozone generator. The ozonated, partly decontaminated water (720) then flows to a tank (760), which can be a contact tank, a static mixer and any combination thereof. The tank need not be large; a tank larger than about 2 1 is adequate, although a 4 liter tank is preferred. In some embodiments, the disinfector also functions as a purifier; in other embodiments, the fully decontaminated water (730) can then flow downstream to a purifier before being distributed.

In the embodiment of Fig. 6, the water flows through both a contact tank and a purifier. Any combination of contact tank and water purifier can be used with the ozone generator. For non-limiting example, in some embodiments, the ozonated water flows directly to the point(s) of use, without passing through either a contact tank or a purifier. In other non-limiting examples, some embodiments have a contact tank but no purifier, while other embodiments have a purifier but no contact tank.

In order to ensure that there is enough ozone in the water, preferably, there is an inline ozone sensor (8), such as, but not limited to, a dissolved oxygen sensor or an oxidation -reduction potential (ORP) sensor at the outlet port of the present purifier. The sensor signal is sent to a microprocessor (9). Since, typically, a low ORP measurement indicates a fault in the ozonation process, if the ORP level is too low, the microprocessor (9) will send an alert that there is a problem in the purifier. The alert can be sent via a "universe of things" or via any method of communicating with an operator that is known in the art.

The microprocessor is configured to perform a communication function selected from a group consisting of: display the ozone level, store the ozone level in a database, display the ozone level as a function of time, provide an alert if the ozone level is outside predetermined limits, and any combination thereof. The communication function can be performed via a wiredly connected display, via a wirelessly connected display, and any combination thereof, but is preferably a wireless connection. The wireless connection can be a cellular modem, a Bluetooth™ connection or any other wireless connector known in the art. In some embodiments, the communication function additionally comprises a member of a group consisting of: display the water flow rate, store the water flow rate in a database, display the water flow rate as a function of time, provide an alert if the water flow rate is outside predetermined limits, display the air flow rate, store the air flow rate in a database, display the air flow rate as a function of time, provide an alert if the air flow rate is outside predetermined limits, display the voltage, store the voltage in a database, display the voltage as a function of time, provide an alert if the voltage is outside predetermined limits, display a difference between input and output pressure, store the difference between input and output pressure in a database, display the difference between input and output pressure as a function of time, provide an alert if the difference between input and output pressure is outside predetermined limits, and any combination thereof.

The disadvantage of a dissolved ozone sensor that it is usually very expensive. Although the ORP sensor provides an indirect measurement of dissolved ozone rather than a direct one, since it is significantly less expensive than a dissolved ozone sensor, the ORP is used in preferred embodiments of the system of the present invention.

An ORP sensor measures the cleanliness of water and its ability to break down contaminants. It has a range of -2,000 mV to +2,000 mV. Since ozone is an oxidizer, the ORP will measure only positive ORP levels (above 0 mV).

ORP sensors work by measuring dissolved oxygen. More contaminants in the water result in less dissolved oxygen because the organics consume the oxygen and, therefore, lower the ORP level. The higher the ORP level, the more ability the water has to destroy foreign contaminants such as microbes, or carbon-based contaminants.

The ORP level can also be viewed as the level of bacterial activity in the water because a direct link occurs between ORP level and Coliform count in water.

In a clean water system, using ORP to measure dissolved ozone works well. However, even moderately turbid (cloudy) water can result in an ORP value far below that which would be expected in the absence of turbidity. If the water is sufficiently turbid, even negative (reducing) values can occur. In general, monitoring ozone with an ORP works well unless the water is dirty enough to be turbid. However, in the system of the present invention, the ORP sensor will be a reliable method of verifying that the water exiting the system will contain sufficient dissolved ozone to inactivate all microbiologically contamination since the system is intended for applications where the water that enters the purifier has low turbidity because it was treated in a municipal water treatment plant, but is contaminated microbiologically because of bad infrastructure that mixed clean water with sewage.

In less-preferred embodiments of the system, each electrode is in direct contact with a PCB. This has the disadvantage that replacement of a worn electrode requires replacement of an entire PCB, increasing the cost and difficulty of repair of the system. In more preferred embodiments, each electrodes is removably mounted to the PCB, so that an electrode can be removed and replaced without need to replace the PCB, or a PCB can be removed and replaced without replacing the electrode.

In some embodiments, fixed contact are used. In such embodiments, contact between the contacts and the electrode can be poor, leading to overheating and scorching of the PCB which would necessitate replacement of the PCB.

In preferred embodiments, the contacts are spring-loaded, so that, even if an electrode and a PCB are not perfectly parallel, the springs ensure that there is full contact between the contacts and the electrode, independent of the height of the contact, thereby preventing "hot spots" and In less preferred embodiments, multiple spacers are used to separate the electrodes. This can lead to leakage of ozone between the spacers.

In preferred embodiments, a single spacer is used, thereby allowing for high-pressure functioning without leaks.

After the water has been purified by the purifier, it passes through the disinfector and is distributed via the building's pipe network, either directly to the consumer or to the water tank on the roof of the building and after that to the consumer. The time that it takes the water to reach the disinfector, either flowing through the pipes or in the water tank, is typically sufficient to provide sufficient contact time between the water and the ozone to inactivate all the pathogens in the water. This ensures that the water that enters the disinfector is virtually pathogen-free.

Purifier

The purifier comprises an adsorption unit, preferably a carbon-based adsorption unit, with a very low pressure drop allowing high flow rates therethrough, which removes chemical compounds such as Arsenic V (oxidized by the ozone from Arsenic III), iron, lead, bromate and pesticides.

Another major function of the purifier is to remove turbidity, mud, sand and any remaining dissolved ozone from the water.

One major problem with adsorption units is the regrowth of bacteria on the surface of the adsorption unit after disinfection. Therefore, the current purifier comprises an anti-regrowth compound that prevents bacteria from settling on the adsorption unit and contaminating the disinfected water.

Fig. 7 shows water flow through an example of an embodiment of a purifier comprising a static mixer where water is driven through an adsorption unit by water pressure. This exemplary embodiment of a purifier is most suitable for a direct installation, that is, an embodiment of the water purification system in which no tank is used. Water flow outside the purifier is shown by black arrows; water flow inside the purifier by white arrows. Water (left black arrow) flows into the purifier inlet (410). It is diverted downward into a central channel in the purifier (420). Ozone (490) enters the purifier from the top and flows downward through the central channel, mixing with the water. At the bottom of the purifier, the water/ozone mixture is diverted sideways along the bottom (430) of the purifier. It is then diverted upward into a blind-ended channel (440). Pressure then drives the water through the adsorption unit (450). After passage through the adsorption unit (450), it enters a side channel (460), from which it passes into an outlet (470) and out of the purifier (right black arrow).

In other embodiments of the system, the ozone is mixed with the water before it enters the purifier. Such purifiers will not have an ozone entry point and may also have other water flow paths within the purifier unit.

Adsorption units can be of any type known in the art that have a suitably small absolute pore size. They can comprise non-woven fiber, woven fiber, alumina, fiber in a matrix, silver, zinc, pseudoboehmite, carbon, zeolite, cellulose, polyester, cotton, nylon, and any combination thereof. The absolute pore size is preferably less than about a micron and is more preferably less than about 0.1 μιη and still more preferably less than about 0.01 μιη. Preferred adsorption unit characteristics include: highly efficient removal of particles above the absolute pore size (preferably greater than 99%), low pressure drop across the adsorption unit, high flow rate through the adsorption unit, a biocidal capability, and any combination thereof.

Non-porous Ceramic Dielectric Coating on Electrodes

In some embodiments of the system of the present invention, the non-porous ceramic dielectric coating on the electrodes is a multilayer thick-film coating. The non-porous ceramic dielectric coating can be produced using a screen-printing technique, as shown in Fig. 8a-c. Fig. 8a shows the beginning of the process of laying down one layer; Fig. 8b shows an intermediate stage in the process of laying down the layer, and Fig. 8c shows the end of the process of laying down the layer. In this embodiment, the electrode (120) is firmly held by a substrate (110) so it does not slip during processing. A mesh screen (160) is held by a frame (130) at a distance above the electrode (110), the distance small enough that pressure from a squeegee (140) can cause the mesh screen (160) to come into contact with the electrode (120). On the upper side of the screen is a precursor for a dielectric, in the form of a paste (150). On the lower side of the screen (160) and adhering to the screen (160) is a layer of emulsion (170); the holes (175) in the emulsion (170) allow the paste (150) to pass through the emulsion (170) and come into contact with the electrode (120).

At the beginning of the process, the paste dielectric precursor (150) forms a layer on top of the mesh screen (160).

In order to form the image on the electrode (120), the squeegee (140) is pressed down onto the mesh screen (160), bringing the portion of the emulsion (170) directly under the squeegee (140) into contact with the electrode (120). As shown in Fig. 8b, the squeegee (140) is them moved across the upper surface of the electrode (120), pressing paste (150) through the holes (175) in the emulsion (170) and onto the electrode (120). The squeegee also presses the paste (150) ahead of itself.

At the end of the process of laying down the layer (Fig. 8c), the squeegee (140) has crossed entirely over the electrode (120), and has forced paste (150) through all the holes (175) in the emulsion (170). A stop (180) prevents unnecessary loss of paste, which can be reused for another electrode or another layer. The mesh screen (160) can now be removed and the paste precursor (150) processed into a non-porous ceramic dielectric coating.

The dielectric precursor layer is then cured, transforming it into a non-porous ceramic dielectric coating. In the curing process, the paste-coated electrode is placed in a drying oven at about 150 degrees C for a few minutes (<10 minutes) to dry the paste and vaporize elements such as solvents and adhesion promoters. The electrode is then placed in an oven and heated, at a predetermined rate, to about 900 degrees C. The oven temperature is held at about 900 degrees C for about 15 minutes, after which the electrode is cooled at a predetermined rate.

In a typical embodiment of the coated electrodes of the present invention, the above process, of screen printing a precursor layer, drying in a drying oven and then heating to about 900 degrees C is repeated 3-5 times, each time producing a ceramic dielectric layer about 20 μιη to about 25 μιη thick so that the total thickness of the non-porous ceramic dielectric coating is about 75 μηι to about 125 μιη. In this manner, the non-porous ceramic dielectric coating can be produced without cracks.

In this process, the high temperature combustion process causes the first layer of the coating to migrate a few μιη into the surface of the stainless steel electrode, thereby improving the adhesion of the coating to the electrode.

In preferred embodiments, the ceramic dielectric coating material has about the same coefficient of expansion as the stainless steel of the electrode, so that the dielectric coating will not crack or spall during heating or cooling of the electrode during use.

In general, the above-described process will not produce a completely homogenous coating nor a coating of uniform thickness. However, the uniformity will be sufficient to prevent formation of air pockets, and the coating will be flat enough and homogeneous enough to prevent arcing or breakdown that can reduce the reliability and lifetime of the electrodes.

EXAMPLE 1 - Disinfector Efficacy

The efficiency of the adsorption unit was tested by an independent laboratory. Two samples were provided to the laboratory, a first sample of water to be input to the system of the present invention, and a second sample of water collected at the output from the system of the present invention. The input water had been deliberately contaminated. For example, it contained a colorant so that it was magenta-colored. As shown in Table 1, all of the contaminants were removed by the system of the present invention - all of the contaminants were below the limits of detection in both tested samples (1 and 2) of the output water.

Table I: Contaminants in water before and after passage through a disinfector of the present invention

19 Arsenic as 158 Below Limit of Below Limit of APHA, 22nd

Quantification Quantification Edition

(LQ: 0.005 mg/L) (LQ: 0.005 mg/L)

20 Bromate (as 26 Below Limit of Below Limit of Lab_P_SOP_228 BrO) Quantification Quantification

(LQ: 0.01 mg/L) (LQ: 0.01 mg/L)

LQ: Limit of QuantiJ ^' ication

DL: Detection Limit

EXAMPLE 2 - System Efficiency

The efficiency of the system of the present invention was tested by an independent laboratory. Water containing a significant load of bacteria was sampled at various points in two embodiments of the system, an embodiment of the type shown in Fig. lb, and an embodiment of the type shown in Fig. lc. Fig. 9a-b shows the sampling points; Fig. 9a shows sampling points (A, D and E) for an embodiment like that of Fig. lb, while Fig. 9b shows sampling points (A, B and C) for an embodiment like that of Fig. lc. Sampling point A is upstream of the disinfector, sampling points B and E are upstream of the purifier (and therefore downstream of the disinfector) and sampling points C and D are downstream of the purifier. Sampling point E is also downstream of the household main water tank.

Table II: Pathogens in water at various points in embodiments of the system of the present invention

5 <1 <1 <1 <1

9 <1 <1 <1 <1

12 <1 <1 <1 <1

The input water contained on the order of 5 million of each type of bacterium. After passage through the disinfector, the bacterial load was very significantly reduced. In the worst case, sampling point B, there were on the order of 150 fetal enterococcus per 100 ml because, since there was only a short distance between the exit from the disinfector and the sampling point, the ozone did not have sufficient time to fully disinfect the water. However, for sampling point E, which is also between the disinfector and the purifier but is downstream of the holding tank so that there is sufficient contact time between the water and the ozone, no bacteria were detectable in the water. In both cases, no bacteria were detectable in the water, except at point D when 12 m of water were sampled, 1 coliform bacterium per 100 ml was found, thus demonstrating the efficiency of the system in removing bacteria from the water.

EXAMPLE 3 - Arsenic Reduction

The efficiency of the system of the present invention was tested by an independent laboratory. Two samples were tested, one containing 230 ppb of Arsenic III and one containing 250 ppb of arsenic III. For each sample, a reference aliquot was collected and two aliquots (A, B) were collected after passage through the system. All the aliquots were sent to the laboratory, where tests were made with the Arsenator Analyzer from Palin Test Ltd, which has a LQ of 2 μg/L. The results are shown in Table III.

Table III Arsenic in water before and after passage through an embodiment of the system of the present invention

No arsenic was found in any of the aliquots after passage through the system; the EPA guidelines recommend that, for drinking water, the level of Arsenic should be less than 10 ppb (10 g/L). In the foregoing description, embodiments of the invention, including preferred embodiments, have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments were chosen and described to provide the best illustration of the principals of the invention and its practical application, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly, legally, and equitably entitled.