Water treatment system
A system for the treatment of water to remove metals and undesirable substances from well and groundwater so as to render the water potable is disclosed. The system employs microbubbles of oxygen, which remain suspended in water at a concentration above 100% of the calculated saturated concentration at a particular temperature and pressure. These microbubbles oxidize undesirable substances in the water, which substances include iron manganese, arsenic, antimony, chrome, aluminum, reduced sulfur compounds, pesticide residues, drug metabolites and/or bacteria. Microbubbles are produced by electrolysis or by sparging through a microorifice. A control system for the electrolytic system is disclosed.
This application claims priority of U.S. Provisional Application Ser. No. 60/813,267, filed Jun. 13, 2006.
FIELD OF THE INVENTIONThe invention pertains to treatment of water to remove metals and undesirable substances from well and groundwater so as to render the water potable.
BACKGROUND OF THE INVENTIONWater for domestic, industrial and farm use frequently is contaminated with minerals, organic substances, and bacteria that render the water unpotable and even dangerous to health. Among these contaminants is ferrous iron, which forms a colloidal mass with water and fouls plumbing. Manganese and arsenic, both toxic metals, are frequently found in water. Another is hydrogen sulfide, which imparts a rotten egg smell to the water. Organic substances may include pesticide residues, drug metabolites and other contaminants that are released into the groundwater. Harmful bacteria such as Salmonella sp., E. coli, Shigella sp. and Clostridia sp. have been implicated in outbreaks of illness with significant mortality.
These contaminants generally have one thing in common: they are inactivated, killed or transformed to innocuous substances when oxidized. Municipalities have long treated their water supplies with oxidants such as chlorine to control contamination. Chlorine is not totally harmless. For those small municipalities or individual farms or homes, it is impractical to use chlorine to treat water.
A widely used treatment system employs the chemical oxidant potassium permanganate to oxidize contaminants. Basically, running water is passed through a bed of permanganate to convert the fouling ferrous iron to the soluble ferric iron and the odorous hydrogen sulfide to non-odorous sulfate. Other contaminants are likewise oxidized to harmless chemicals and bacteria are killed. This system, though effective, is difficult and expensive to maintain and requires periodic backflushing and replacement of the permanganate. Permanganate being a toxic and reactive chemical, service of the system can be hazardous.
Oxygen may be used. Oxygen content of water may be raised by several means: bubbling with air; spraying the water into the air; applying pressure to increase the dissolved oxygen, or by the electrolysis of water.
U.S. Pat. No. 6,171,469 described raising the oxygen content of water by passing the water through a set of electrolysis cells. In order to raise the oxygen content to the desired 13-17 ppm, it is necessary to recirculate the water past the cells 15 to 55 times.
None of these methods except the permanganate system deliver treated water on demand, but require the construction of a retention tank and thus are not convenient for home or farm use.
SUMMARY OF THE INVENTIONThe present invention provides one or a plurality of emitters contained in one or a plurality of electrolysis chambers through which water flows. When activated, the emitters cause the evolution of microbubbles of oxygen. The emitters are connected to a power source controlled by a controller containing a flow switch. When the flow switch senses water demand, that is, when a spigot is opened, the controller causes voltage to be applied to the electrolysis cells. The electrolysis cell or cells comprise electrodes separated from each other by a critical distance as more fully described in co-pending patent application Ser. No. 10/732,326 (the “'326” application), the teachings of which are incorporated by reference. Briefly, the anode and cathode are separated by 0.005 to 0.140 inches. The most preferred critical distance is 0.065 inches. Any cathode or electrode known in the art may be used. Any number of emitters may be arranged in the electrolysis chamber; the following examples show a typical array of three rectangular emitters, but it is understood that the invention is not limited to three, but may comprise one to several or hundreds of emitters, depending on the volume of running water to be treated. Likewise, it may be convenient to pass the water through a plurality of chambers, arranged in series or in parallel, in order to make a more compact unit or to treat large quantities of flowing water.
In the preferred embodiment, the cathode and electrode are formed of the same material and the controller causes the polarity to be reversed at a set signal. Many cathodes and anodes are commercially available. U.S. Pat. No. 5,982,609 discloses cathodes comprising a metal or metallic oxide of at least one metal selected from the group consisting of ruthenium, iridium, nickel, iron, rhodium, rhenium, cobalt, tungsten, manganese, tantalum, molybdenum, lead, titanium, platinum, palladium and osmium or oxides thereof. Anodes are preferably formed from the same metallic oxides or metals as cathodes. Electrodes may also be formed from alloys of the above metals or metals and oxides co-deposited on a substrate. The cathode and anodes may be formed on any convenient support in any desired shape or size. The most preferred electrode is titanium coated with iridium oxide.
Polarity of the electrodes is reversed in order to clean the electrodes of deposited minerals. The time of reversal may be set for any convenient interval or be activated by any convenient means. The means for reversal include: reversal each time the well pump turns on; when the water flow is initiated; at timed intervals from 45 seconds to 24 hours or more; or manually. When the water flow is intermittent, it is convenient to program the controller to change polarity each time the flow switch detects a flow of water. The preferred embodiment is self-cleaning; mineral residue tends to build up on the cathode when current is flowing. When the current is reversed, the anode and the cathode change polarity. The mineral buildup on the former cathode is repelled and starts to form on the new cathode. This reversal of polarity limits the amount of buildup and the emitter is essentially self-cleaning.
The system is supplied with valves to direct the water flow. The water may be directed to bypass the electrolysis chamber, to pass through the chamber to be oxygenated, or a separate line is provided to backflush the electrolysis chamber to remove any minerals that may have accumulated in the vicinity of the electrodes.
Any embodiment is preferably supplied with fail-safe sensors, valves and the like, devices known to those in the art. When the flow switch senses that there is no water flow, the power is turned off. A temperature sensor in the electrolysis chamber shuts off current if the current is applied but no water is flowing. In that case, the temperature in the chamber rises and the temperature sensor will instruct the controller to cut the voltage. Likewise, relief valves to release fluid in case of liquid or gas pressure buildup may be located at any point in the system. A gas relief valve is best vented to the outside.
The system includes an electrical circuit to control the activation of the emitters, to reverse polarity and to inactivate the emitters when water is not flowing.
In an alternate embodiment, the oxygen is provided by bubbling it into a chamber. In this embodiment, the oxygen can be supplied by tank or generated on the site by PSA technology. The embodiment that comes closest to approximating the result of the present invention is sparging oxygen through a microorifice in order to produce microbubbles of oxygen.
Water may contain many undesirable substances, such as iron, manganese, arsenic, antimony, chrome and aluminum. The reduced salts are generally soluble, while oxidized metals, such as Fe2O3 or MnO2 are insoluble and form fine precipitates. Reduced sulfur compounds, such as H2S, have a noxious odor, while oxidized sulfur compounds are generally odorless. Other undesirable substances include pesticide residues, drug metabolites and bacteria. In all embodiments, it is recommended to pass the effluent of treated water through a final filter bed in order to remove fine precipitates and to improve the clarity of the water. Such filter beds are well known in the art and include: Birm filter, Greensand, Pyrolux. Filtersand, Filter-Ag, activated carbon, anthracite and garnet.
When the water is hard, that is, contains divalent metals such as calcium and magnesium, the portion of the effluent intended to be heated, may pass through a water softener.
In the following discussion, a water treatment system with three emitters in one chamber is used as an example. The voltages and flow rates below are suitable for this example, but it should be understood that more or fewer cells can be used, depending on the needs of the installation. It may be convenient to pass the water to be treated through a plurality of chambers to make a more compact system or to treat large volumes of water. The chambers may be arranged in series or in parallel. One of the pressing needs is the removal of ferrous hydroxide, which has an odor, stains and fouls plumbing. Oxidized iron is non-reactive and will not stain or foul plumbing, nor does it have an objectionable odor. The microbubbles evolved by the emitters are effective in rapid oxidation of contaminants both because of the high oxygen content achieved in the water and because of the large surface area for reaction. A final filter is preferred in order to remove fine precipitates of oxidized iron and other oxidized metals and to improve the clarity of the water. In the following examples, specific conditions of power supply, size and flow rates are provided for illustrative purposes only. Those skilled in the art can readily make adjustments in power supply, size and flow rates to provide the benefits of this invention.
Example 1 Experimental ModelTurning to
Turning to
Either the embodiment in
- 1. Bypassing the system: Valve 2 is open; valves 3 and 9 are closed. Water flows from intake 1 to outlet 10, bypassing the emitters.
- 2. Through the system: Valves 3 and 9 are open; valves 2, 14 and 15 (
FIG. 2 only) are closed. Water flows from intake 1 through electrolysis chamber 4. The flow switch 5 senses flow and controller 6 activates power source 7 to supply current to the emitters. - 3. Through the system with self-cleaning feature activated. Valves 3 and 9 are open; valves 2, 14 and 15 (
FIG. 2 only) are shut. The flow switch 5 senses flow and controller 6 activates power source 7. Controller 6 switches polarity as programmed. For intermittent use, it may be convenient to program the controller to switch polarity each time water flow is started. - 4. Backflush cycle, the model of
FIG. 2 only: Valves 14 and 15 are open, valves 3 and 9 are closed. Water is introduced to the electrolysis chamber through intake 18, flows in a retro direction through the chamber and out the outlet 19. The electric circuitry is bypassed and adjustments are not programmed, but are made manually.
This description is based on a example system with three emitters and the self cleaning polarity reversal on each initiation of water flow. Adjustments can be made for bigger or smaller systems. Circuit operation starts with applying line voltage, 120 V AC, to the power supply 26, which transforms the line voltage to 12 V DC. The controller circuit is in electrical communication with flow switch 23, temperature sensor 22 and push button switch 21 which activates the circuit, if the temperature sensor 22 indicates cool, thereby allowing 12 volts to be applied to the push button switch 21. When this push button switch is pushed, it energizes relay 24 K1A. The connections on this relay are such that it remains energized after the push button is released. The other contacts on this relay look at the flow switch to see if water is flowing. If so, the next relay 25 K1B is energized, applying 120 V AC to the second power supply 20 and relay 27 K2. K2 is a sequencing relay, the contacts of which will change state when energized and remain in an energized state when power is removed. The next time the relay is energized, the contacts change state and then stay in that position.
When 120 V AC power is supplied to the power supply 20, it sends DC voltage onto its output connections. Relays 28K3, 29K4, and 30K5 send the current through terminal boards 31, 32 and 33 to the emitters. If K2 is in one position, the voltage applied to the emitters is “forward” biased. The next water flow detection will change the state of K2 and the relays will change state, resulting in a reversal of polarity on the emitters. Oxygen will be produced during either state.
The action will continue indefinitely if the temperature sensor detects no increase in temperature. If the sensor sees an increase in temperature above its set point, it will open the circuit and remove the 12 V DC power to the relays, thereby shutting down the circuit. The circuit can be restarted only by activating the button switch again. When the spigot is turned off, there is a slight temperature rise until the flow switch turns off the controller. This rise is not enough to trigger the much higher set point on the temperature switch. Hence the system will turn on again once the flow switch detects flow. The temperature switch is a safety device and preferably, once the temperature switch inactivates the power system, manual intervention is required to reactivate the system.
Example 3 Emitter ConfigurationsDepending on the volume of fluid to be oxygenated, the emitter of this invention may be shaped as a circle, rectangle, cone or other model. One or more may be set in a substrate that may be metal, glass, plastic or other material. The substrate is not critical as long as the current is isolated to the electrodes by the nonconductor spacer material of a thickness from 0.005 to 0.140 inches, preferably 0.030 to 0.075 inches, most preferably 0.065 inches. Within this distance, micro- and nanobubbles of oxygen are evolved. These bubbles are so small that they cannot escape and build up into what may be termed a colloidal suspension of oxygen in an aqueous medium. Oxygen concentrations of 260% of calculated saturation at a particular temperature and pressure have been achieved in a stationary container. The oxygen suspension in a flow-through unit can be so concentrated with oxygen that the water appears milky. In addition to the high oxygen content achieved, the microbubbles have a larger surface area for reaction than ordinary-sized bubbles. While any configuration may be used in the water treatment system, a funnel or pyramidal shaped cell was constructed to treat larger volumes of fluid.
A. An experimental system, such as that in
Calculations of power expended and cost thereof were made. The current varied between 3.3 and 3.8 amps. At 12 volts, the power used was about 48 Watts for each emitter or about 144 watts. The system was activated for about two hours each day, at a daily cost (current electric company rates) of about 3.4 cents per day.
This experimental system did not feature the self-cleaning reverse polarity feature. The system was run for six days, during which time 1400 gallons of water was drawn. At this time, the electrodes began to show some mineral deposits.
B. The first polarity-reversing experimental system, with three emitters, was installed in a home provided with well water, containing 2 to 3 ppm iron. The flow rate in the system was 6 gallons/minute. Polarity of the emitters was reversed every time the flow was started, that is, when a faucet was opened, about 70 times per day. This unit was equipped with a Birm filter. Tests showed complete removal of iron, down to 0 detectable ppm.
C. The second polarity-reversing experimental system was installed at a site where the effluent was also used for irrigation. The water contained 12.75 ppm iron and operated at a 15 gallon/minute rate. Polarity was reversed every time the well pump was started, which varied between 14 and 18 times a day.
As for the prototype in Example B, the iron in the effluent was undetectable and the effluent was passed through a Birm filter and the results showed that iron levels were undetectable. These results were verified by an independent testing laboratory.
D. The third polarity-reversing experimental system was installed at a site where the water contained both 10 ppm iron and 2.25 ppm hydrogen sulfide. Flow rate was 7 gallons per minute, and the polarity was reversed each time the well pump was started, about 14 times per day. The effluent was passed through a greens and filter. Iron and hydrogen sulfide levels in the effluent were undetectable.
Example 5 Laboratory Testing of 4.0-5.0 ppm IronA. Seventy gallons of well water testing 4 to 5 ppm were passed through conduit equipped with a three plate, twelve-inch emitter at 12 Volts. The flow rates were varied and the iron content was measured after the effluent passed through a 9 by 48 inch Birm filter. The first flow rate tested was two gallons per minute. Iron content was below 0.5 ppm (the practical lower limit of measuring). When the flow rate was increased to 2.7 gallons per minute, the iron content was less than 0.5 ppm. The flow was increased to 4.87 gallons per minute and then to six gallons per minute. The iron content of the effluent was 0.5 ppm or below.
B. Trailer testing. A special 5 ft. by 8 ft. trailer was outfitted in order to conduct water testing at various sites and to verify results before units were installed. The trailer was equipped with two polarity-reversing oxygenator chambers, a power supply, and two Birm filters. A 14 inch by 65 inch Birm filter for lower flow rates and a 21 inch by 54 inch Birm filter for higher rates were used. The trailer had its own power generator and large flow pump so iron, hydrogen sulfide and manganese removal can be tested immediately on site.
With this trailer, the ability of the system to remove manganese was tested. At the City of Brooklyn Park, Minn., various wells tested between 1.3 ppm to 2.7 ppm manganese. With the two chambers, powered on the trailer, and at flow rates up to 10 gallons/minute, the manganese was oxidized and 100% removed by the 21 by 54 inch Birm filter.
Example 6 Compact Unit with Self-Cleaning FeatureNew embodiments have been developed that are suitable for factory assembly into a compact unit within a case for convenient installation. The improved features include a self-cleaning feature.
It should be noted that the details of the elements of the water treatment system are more fully described in examples 1 to 4. The embodiments described in this example 6 are equipped with a polarity reversing control. The process continues as long as the water flow exceeds the preset flow.
Example 7 Bubbling or Sparging with OxygenAs mentioned above, it is well-known to attempt to improve the quality of water by aeration. Previous techniques of bubbling air or oxygen were not effective in reducing metals and sulfur compounds. While the embodiments described above produce the most improvement in quality of water, other means may produce an approximation of those results. Technology exists to bring pure oxygen to a site and inject it into the water in the form of microbubbles, which raises the oxygen content of the water and also presents a greater surface area for reaction with undesirable substances. A tank of oxygen may be used. The PSA methods passes air through a filter that removes the dinitrogen, leaving pure oxygen.
Various embodiments of emitter were tested. Round, flat or pyramid configuration emitters were tested in the laboratory for over 30 days. The emitters chosen were of titanium. The current was switched at varying intervals from five seconds to three hours. No buildup of mineral deposits was observed. Depending on the site and the user's preference, in the functioning water treatment system, the polarity can be set to reverse:
each time the well pump turns on and the water pressure increases;
when the water flow is initiated;
at timed intervals from 45 seconds to 24 hours or more;
or manually.
Each choice has its advantages with the purpose of minimizing the frequency of reversing polarity in order to prolong the useful life of the electrodes while maintaining the efficacy of water treatment. In general, if the water use is constant, the timing mode can be selective. When water use is intermittent, as is generally the case with home use, a mode based on pump or water flow is preferred.
Those skilled in the art may readily make insubstantial changes or additions. Such changes or additions are within the scope of the appended claims.
Claims
1. A water treatment system comprising one or a plurality of emitters in one or a plurality of electrolysis chambers through which water flows, operably connected to a power source controlled by a controller comprising a flow switch which senses water flow and directs the controller to apply voltage to the emitters whereupon microbubbles of oxygen are evolved.
2. The emitters of claim 1 wherein the emitters comprise cathodes and anodes in aqueous communication with each other and separated by a critical distance of 0.005 to 0.75 inches.
3. The emitters of claim 2 wherein the cathodes and anodes are separated by a critical distance of 0.65 inches.
4. The emitters of claim 1 wherein the cathodes and anodes are formed from the same material, the material being titanium, ruthenium, iridium, nickel, iron, rhodium, rhenium, cobalt, tungsten; manganese, tantalum, molybdenum, lead, platinum, palladium, osmium or oxides thereof.
5. The water treatment system of claim 3 wherein the cathode and anode are formed from titanium coated with iridium oxide.
6. A control system for the water treatment system of claim 1 comprising a flow switch capable of sensing water flow above a set point, with electrical communication to a power source causing alternating current to be transformed to direct current, the direct current thereafter passing through relays to activate the emitters to cause the evolution of microbubbles, which activation continues as long as water is flowing.
7. The control system of claim 6 further comprising a pressure switch and/or a temperature switch operably connected to a control valve so that when the pressure and/or temperature rises above a set point, a control switch terminates the application of current to the emitters.
8. The control system of claim 6 further comprising a means to reverse polarity of the direct current at a predetermined set signal.
9. The set signal of claim 8 which is an increase of pressure from a well pump, initiation of water flow, a timed interval or manual.
10. A water treatment system comprising a chamber with static mixer through which water flows, a source of oxygen, and a microorifice through which oxygen is sparged into the bottom of the chamber thereby forming microbubbles of oxygen.
11. The source of oxygen which is a tank of oxygen or PSA technology.
12. The water treatment systems of claims 1, 6 and 10 further comprising a final filter, through which the water treated in the chamber flows.
13. The filter of claim 11 comprising Birm filter, Greensand, Pyrolux, Filtersand, Filter-Ag, activated carbon, anthracite and/or garnet.
14. A water treatment system comprising a source of microbubbles of oxygen for oxidizing undesirable substances in water.
15. The undesirable substances of claim 14 which are iron manganese, arsenic, antimony, chrome, aluminum, reduced sulfur compounds, pesticide residues, drug metabolites and/or bacteria.
16. The undesirable substances of claim 14 which are iron, manganese and/or hydrogen sulfide.
Type: Application
Filed: Jun 6, 2007
Publication Date: Dec 13, 2007
Inventors: Rudolph R. Hegel (Richfield, MN), Robert K. Sorensen (Champlin, MN)
Application Number: 11/810,540