Abstract:
Water purification systems utilizing oxidation. By passing water through a chamber of air, the impurities within the water, such as iron, manganese, and/or hydrogen sulfide gas, may be oxidized. The oxidized constituents in the water may then precipitate out and be removed by filter media. Thus, by utilizing oxidation, the impurities most commonly found in a consumer&#39;s water are readily removed. Additionally, the water purification systems of the present invention may also elevate the pH, i.e., reduce the hydronium ion concentration, of the water when the water is acidic. By raising the pH of the water, the oxidation of impurities, such as iron and manganese, is more complete and also occurs at a faster rate. Additionally, the corrosivity of the water is also reduced when the pH is elevated.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 61/032,628, filed Feb. 29, 2008. 
    
    
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to water purification systems and, particularly, to water purification systems utilizing oxidation. 
     2. Description of the Related Art 
     Water purification systems are commonly used to purify water drawn for consumer use. The water may be obtained directly by the consumer from an individual well or may be provided to the consumer by a municipality or corporation. Irrespective of how the water is provided to the consumer, the water may include impurities that the consumer considers to be undesirable. For example, iron, manganese, hydrogen sulfide, and/or arsenic may be dissolved or otherwise contained within the water. These compounds may negatively effect the clarity, color, odor, and/or taste of the water. Hydrogen sulfide, for example, has an unpleasant odor, is highly corrosive, and is also highly toxic. 
     A variety of water processing systems are available, either for commercial or consumer use. For example, zeolite based water softener systems are widely used to control water hardness, i.e., remove iron from water, but do not remove other impurities, such as hydrogen sulfide. Additionally, as the impurities contained within an individual consumer&#39;s water vary geographically, a conventional system may not successfully remove some of an individual consumer&#39;s specific impurities. Moreover, depending on the conditions under which the water was obtained, the concentrations of the impurities may be widely varied, rendering consistent treatment difficult. 
     SUMMARY 
     The present invention provides water purification systems and, particularly, water purification systems utilizing oxidation. By passing water through air, the impurities within the water, such as iron, manganese, and/or hydrogen sulfide gas, are oxidized. The oxidized constituents in the water then precipitate out and are removed by filter media. Thus, by utilizing oxidation, the impurities most commonly found in a consumer&#39;s water are readily removed. Additionally, the water purification systems of the present invention may also elevate the pH, i.e., decrease the hydronium ion concentration, of the water when the water is acidic. By raising the pH of the water, the oxidation of impurities, such as iron and manganese, is more complete and also occurs at a faster rate. Additionally, the corrosivity of the water is reduced when the pH is elevated. 
     In one exemplary embodiment, the present invention provides a two-tank water purification system. The two-tank system utilizes a first, oxidation tank that includes a headspace of air. As water passes through the headspace, impurities in the water are oxidized. The water is then transferred to the second, filter tank where impurities precipitated in the water pass through filter media and are removed from the water. In another exemplary embodiment, the present invention provides a three-tank water purification system. The three-tank water purification system is similar to the two-tank system in that it utilizes a first, oxidation tank and a second, filter tank. However, the three-tank system also provides a third, ion resin tank. By passing the water through the ion resin tank, the hardness of the water is reduced. Advantageously, by utilizing an oxidation tank, the present invention coverts arsenic(V) into arsenic(III), which may be removed by filter media contained within the filter tank. Thus, the present systems allow for a substantial reduction in the arsenic level in a consumer&#39;s water supply. 
     In one form thereof, the present invention provides a system for removing impurities from water, the system including: a water inlet; an oxidation tank having a headspace of air contained therein, said oxidation tank in fluid communication with said water inlet through a first pathway; a venturi in fluid communication with said water inlet and said oxidation tank through a second pathway, wherein water received from said water inlet may enter said oxidation tank through both of said first pathway and said second pathway, said venturi having an air inlet in constant fluid communication with the ambient environment, wherein air drawn through said air inlet of said venturi is delivered to said oxidation tank to create said headspace of air; a filter tank in fluid communication with said oxidation tank, said filter tank having filter media contained therein, wherein water travels through said headspace of air in said oxidation tank to oxidize the impurities in the water and then passes through said filter media in said filter tank to remove the impurities from the water; and a water outlet in fluid communication with said filter tank. 
     In another form thereof, the present invention provides a system for removing impurities from water, the system including: a water inlet; an oxidation tank having a headspace of air contained therein, said oxidation tank in fluid communication with said water inlet through a first pathway; a venturi in fluid communication with said water inlet and said oxidation tank through a second pathway, wherein water received from said water inlet may enter said oxidation tank through both of said first pathway and said second pathway; a filter tank in fluid communication with said oxidation tank, said filter tank having filter media contained therein, wherein water travels through said headspace of air in said oxidation tank to oxidize the impurities in the water and then passes through said filter media in said filter tank to remove the impurities from the water; an ion resin tank in fluid communication with said filter tank, said ion resin tank having a resin media position therein, wherein the water passes through said resin media to lower the hardness of the water; and a water outlet in fluid communication with said ion resin tank. 
     In yet another form thereof, the present invention provides a method of removing impurities from water, the method including: passing water through a powerhead and into an oxidation tank; passing the water through a headspace of air to oxidize impurities in the water; transferring the water to a filter tank; passing the water through filter media contained within the filter tank to filter oxidized impurities from the water; passing the water through the powerhead; and providing the water to a consumer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following descriptions of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is cross-sectional, schematic view of a water purification system of the present invention according to an exemplary embodiment depicting the system in a service cycle; 
         FIG. 2  is a cross-sectional, schematic view of the system of  FIG. 1  depicting the system in a backwash cycle; 
         FIG. 3  is a cross-sectional, schematic view of the system of  FIG. 1  depicting the system in a slow rinse cycle; 
         FIG. 4  is a cross-sectional, schematic view of the system of  FIG. 1  depicting the system in a fast rinse cycle; 
         FIG. 5  is a cross-sectional, schematic view of a water purification system of the present invention according to another exemplary embodiment depicting the system in a service cycle; 
         FIG. 6  is a cross-sectional, schematic view of the system of  FIG. 5  depicting the system in a backwash cycle; 
         FIG. 7  is a cross-sectional, schematic view of the system of  FIG. 5  depicting the system in a slow rinse cycle; 
         FIG. 8  is a cross-sectional, schematic view of the system of  FIG. 5  depicting the system in a fast rinse cycle; and 
         FIG. 9  is a cross-sectional, schematic view of the system of  FIG. 5  depicting the system in a refill cycle. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate preferred embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION 
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate preferred embodiments of the invention and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     Referring to  FIG. 1 , a two-tank water purification system manufactured in accordance with the present invention is shown in a service cycle. In this cycle, water enters the purification system through inlet  10 , travels through pipes  11 ,  12 , which at least partially define a first pathway, and enters tank  16 . Fluid communication between inlet  10  and pipe  12 , as well as outlet  32  and pipes  30 ,  34  described below, may be controlled by a standard water softener powerhead, such as powerhead  13 . In one exemplary embodiment, powerhead  13  is a Fleck®Model 2510 control valve drive assembly commercially available from Pentair, Inc. of Golden Valley, Minnesota. Fleck® is a registered trademark of Fleck Controls, Inc. of Brookfield, Wisconsin. 
     As water enters the system, if the flow of water through inlet  10  is high enough, a portion of the water traveling through pipe  11  will be diverted through pipe  18 , which at least partially defines a second pathway parallel to the first pathway, and venturi  20 . In one exemplary embodiment, the second pathway is discrete from the first pathway from inlet  10  to oxidation tank  16 , described below. While the flow rate required in any particular system will depend on the size of the purification system, the pressure of the inlet water, and the discharge pressure of the water, a residential system may draw air near its approximate peak flow rate of 10 gallons per minute, for example. As water passes through venturi  20 , air enters the water traveling therethrough via venturi air intake  22 . In order to control the amount of air entering the system, the opening defining air intake  22  may be restricted. 
     The water traveling through pipes  12 ,  18  then enters first, oxidation tank  16 . As the water enters tank  16  it falls through air defining head space  14  in tank  16 , causing impurities in the water to be oxidized. The water then exits tank  16  via pipe  24  and travels to second, filter tank  26 . The water within tank  26  is then filtered through filter media  28  and exits tank  26  via pipe  30 . Filter media  28  may be a calcium carbonate media, filter sand, Birm® filter media, greensand, dolomite, Filter-Age filter media, or an arsenic absorbent media, for example. Birm® and Filter-Age are registered trademarks of Clark Corporation of Windsor, Wisconsin. In one exemplary embodiment, a portion of the filter media will be dissolved in the water if the water is acidic, i.e., has a pH less than 7.0. As a result, the pH of the water will be increased, facilitating greater oxidation of the impurities and lessening the corrosivity of the water. When operating in the service cycle, pipe  30  is in fluid communication with outlet  32 . Outlet  32  then connects to the water service line of a consumer. 
     Advantageously, by passing the water through a headspace of air, the impurities in the water are oxidized and begin to precipitate out of the water. For example, iron, manganese, and hydrogen sulfide may all be oxidized. Additionally, arsenic(V) may be converted to arsenic(III) as a result of oxidation. While arsenic(V) is able to pass through filter media  28 , arsenic(III) is captured in filter media  28  and removed from the water. As a result, the present purification system provides a substantially higher arsenic removal rate than standard purification systems when an arsenic absorbent media is employed. 
     Referring to  FIG. 2 , in order to flush the purification system and remove any particulate matter from filter media  28  within tank  26 , the system enters a backwash cycle. In the backwash cycle, inlet  10  and pipe  11  are automatically placed in fluid communication with pipe  30  by powerhead  13 , causing intake water traveling through pipes  11 ,  30  to enter tank  26 . Specifically, powerhead  13  may place inlet  10  and pipe  11  in fluid communication with pipe  30  after the passage of a predetermined amount of time or after the passage of a predetermined amount of water through powerhead  13 , for example. As the water exits the bottom of pipe  30 , it travels through filter media  28  dislodging various particulate matter and, once tank  26  is filled, the water exits tank  26  via pipe  24 . Water traveling through pipe  24  then enters tank  16  and begins to fill tank  16 . As tank  16  fills, air trapped within head space  14  is forced through pipe  12 , which, as a result of the activation of powerhead  13  described above, is now in fluid communication with drain pipe  34 . Once the water level reaches pipe  12 , the water travels through pipe  12  and exits through drain pipe  34 . After running for a sufficient period of time to remove the particulate matter from the system via drain pipe  34 , the system enters a slow rinse cycle. 
     Referring to  FIG. 3 , the slow rinse cycle is shown. This cycle is utilized to replenish head space  14  with fresh, oxygenated air. Specifically, in this cycle, powerhead  13  is activated to prevent fluid communication between pipe  11  and pipe  12 . As a result, water traveling through pipe  11  is forced through pipe  18  and venturi  20 . As the water travels through venturi  20 , air enters air intake  22  and is combined therewith. The water is then delivered via pipe  18  into tank  16 . Once within tank  16 , the air and water separate and head space  14  begins to form. Water will continue to fill tank  16  and compress the air within head space  14  until head space  14  and the water contained within tank  16  are at substantially equal pressures. At this point, as additional water enters tank  16 , it will begin to travel up pipe  24  and into tank  26 . The water within tank  26  will then travel through filter media  28  and enter pipe  30 . Pipe  30 , as a result of the activation of powerhead  13  described above, is now in fluid communication with drain pipe  34  and water traveling through pipe  30  will exit the system via drain pipe  34 . 
     Once the slow rinse cycle is complete, the system will enter a fast rinse cycle, shown in  FIG. 4 . In this cycle, powerhead  13  is activated to allow water entering inlet  10  to travel through pipes  11 ,  12  and enter head space  14  of tank  16 . Additionally, if the volume of water traveling through pipe  11  is sufficiently high, a portion of the water will be diverted through pipe  18  and travel through venturi  20  to draw air into the water, as described above. As the water enters tank  16  via pipes  12 ,  18 , the air will separate from the water and rise within tank  16  to maintain head space  14 . The water will then exit tank  16  via pipe  24  and enter tank  26 . After passing through filter media  28 , the water will enter pipe  30  and exit the system via drain pipe  34 . Once the fast rinse is complete, the system will reenter the service cycle. Specifically, powerhead  13  is again actuated and inlet  10  is placed in fluid communication with pipe  11 , as described above. The two-tank system will then, after the passage of a predetermine amount of time or the passage of a predetermined amount of water through powerhead  13 , repeat the process of performing each of the cycles described in detail above. 
     Referring to  FIGS. 5-9 , a three-tank water purification system manufactured in accordance with the present invention is shown. Similar to the two-tank water purification system described in detail above with reference to  FIGS. 1-4 , the three-tank system is a water purification system based, in part, on oxidation. However, in addition to the tanks described above with reference to the two-tank system, the three-tank system adds a third, water softener and/or ion resin tank to facilitate additional water treatment. Specifically, the third tank is used to lessen the hardness of the water. 
     Referring to  FIG. 5 , the three-tank water purification system is shown in a service position. Thus, water received through inlet  50  will travel through pipes  52 ,  54 , which at least partially define a first pathway, and through pipe  56 , which at least partially defines a second pathway parallel to the first pathway, to enter tank  58 . In one exemplary embodiment, the second pathway is discrete from the first pathway from inlet  50  to oxidation tank  64 , described below. Fluid communication between pipes  52 ,  54 , as well as outlet  76  and pipes  74 ,  78  described below, may be controlled by a standard water softener powerhead, such as powerhead  53 . In one exemplary embodiment, powerhead  53  is a Fleck® Model 2510 automatic backwash valve drive assembly commercially available from Pentair, Inc. of Golden Valley, Minnesota. 
     The water entering tank  58  travels through air within head space  60 , oxidizing impurities in the water and causing them to precipitate out of the water. The water then travels through pipe  62  and enters tank  64  where it passes through filter media  66 . Filter media  66  may be a calcium carbonate filter media, filter sand, Birm® filter media, greensand, dolomite, Filter-Ag® filter media, or an arsenic absorbent media, for example. Filter media  66  captures the precipitated impurities while allowing the water to pass therethrough. In one exemplary embodiment, a portion of the filter media will be dissolved in the water if the water passing therethrough is acidic, i.e., has a pH less than 7.0. As a result, the pH of the water will be increased. The water then enters pipe  68  and travels to tank  70 . Within tank  70 , the water travels through resin media  72  and exits via pipe  74 , which is in fluid communication with outlet pipe  76 . 
     In one exemplary embodiment, resin media  72  may be a high capacity ion exchange softener resin or a fine mesh ion exchange softener resin, for example. By passing the water through resin media  72 , the hardness of the water is substantially reduced. In one exemplary embodiment, the hardness of the water is reduced to less than 5 parts per million of calcium carbonate. Additionally, by passing the water through resin media  72 , arsenic, nitrates, and/or tannic acid may also be substantially removed from the water. In one exemplary embodiment, resin media  72  is selected so that it will remove any substance with a cationic or anionic valence from the water. 
     In order to backwash resin media  72  and filter media  66 , the three-tank purification system is placed into a backwash cycle, as shown in  FIG. 6 . Referring to  FIG. 6 , water traveling through inlet  50  passes through pipe  52 , which, as a result of activation of powerhead  53 , is now in fluid communication with pipe  74 . Specifically, powerhead  53  places pipes  52 ,  74  in fluid communication with one another after the passage of a predetermined amount of time or after the passage of a predetermined amount of water through powerhead  53 , for example. As a result, the water travels through pipes  52 ,  74  and enters tank  70  passing through resin media  72 . The water then travels through pipe  68  into tank  64  and passes through filter media  66 , removing particulate matter therefrom. The water then exits tank  64  via pipe  62  and enters tank  58 . 
     As water enters tank  58 , the water level within tank  58  rises and forces the air in head space  60  out of tank  58  through pipe  54 , which, as a result of the activation of powerhead  53  described above, is now in fluid communication with drain pipe  78 . Once the water level within tank  58  reaches pipe  54 , the water travels through pipe  54  to drain pipe  78  and exits the system. Additionally, to prevent water exiting tank  58  from entering inlet  50  through pipe  56 , a check valve is provided along the length of pipe  56 . After running for a sufficient period of time to remove the particulate matter from the system and discharge the same through drain pipe  78 , the system enters a slow rinse cycle. 
     Referring to  FIG. 7 , during the slow rinse cycle, the three-tank purification system operates in several ways like a conventional water softener. Specifically, during the slow rinse cycle, valve  80  is opened allowing for brine to be drawn from salt tank  84  through pipe  86 . In one exemplary embodiment, valve  80  is electronically actuated by operation of powerhead  53 . As water enters inlet  50  and travels through pipe  52 , a portion of the water will be diverted through pipe  56  where the water travels through venturi  82 . As the water travels through venturi  82 , it draws brine from salt tank  84  through pipe  86  and into pipe  56 . The brine traveling through pipe  56  then enters tank  58 . The water and brine then travel from tank  58  through pipe  62  and into tank  64 . Once within tank  64 , the water and brine travel through filter media  66  and pipe  68  to enter tank  70 . The water and brine are then drawn through resin media  72  to regenerate resin media  72 . The water and remaining brine then exit tank  70  through pipe  74 , which, due to activation of powerhead  53 , is in fluid communication with drain pipe  78 . 
     However, unlike a conventional water softener, when salt tank  84  is emptied to a level below the inlet of pipe  86 , a check valve does not stop the flow of fluid into pipe  86 . As a result, air from the ambient environment begins to enter pipe  86  and is pulled into pipe  56 , ultimately entering tank  58  through venturi  82 . In this matter, the air within tank  58  is refilled in a manner similar to that described in detail above with reference to the two-tank purification system. Once a sufficient level of air has accumulated in tank  58  to form head space  60 , valve  80  is closed, such as by activation of powerhead  53 , and water flowing from inlet  50  is allowed to flow through pipes  52 ,  56  and into tank  58 . Water will continue to enter tank  58  and will pressurize head space  60  until the pressure of the air within head space  60  is substantially equal to the pressure of the water. Once the pressures are equilibrated, water begins to rise in pipe  62  and travel to tank  64 . The water then travels through filter media  66  and pipe  68  to enter tank  70 . Once within tank  70 , the water will travel through resin media  72  and pipe  74 , which is in fluid communication with drain pipe  78 , allowing the water to exit the system. Once head space  60  is filled and pressurized, the system enters a fast rinse cycle. 
     Referring to  FIG. 8 , once in the fast rinse cycle, valve  80  is closed preventing additional brine and/or air from entering pipe  56 . As water enters inlet  50  and travels through pipes  52 ,  56  it enters tank  58 . The water then travels from tank  58  through pipe  62  and into tank  64 . Once within tank  64 , the water travels through filter media  66  and pipe  68  to enter tank  70 . The water then passes through resin media  72  and exits tank  70  through pipe  74 , which, due to activation of powerhead  53 , is in fluid communication with drain pipe  78 . Once the fast rinse cycle is completed, the system enters a refill cycle. 
     Referring to  FIG. 9 , once in the refill cycle, powerhead  53  is activated and valve  80  is again opened. In one exemplary embodiment, valve  80  is electronically actuated by operation of powerhead  53 . Additionally, water is diverted through pipe  56  and pipe  86  to enter salt tank  84 . Once salt tank  84  is sufficiently filled with water, valve  80  is closed and the three-tank purification system reenters the service position. The three-tank system will then repeat the process of performing each of the cycles described in detail above after the passage of a predetermined amount of time or the passage of a predetermined amount of water through powerhead  53 . 
     While this invention has been described as having preferred designs, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.