Abstract:
A water treatment apparatus includes a sand filter and a second stage purification step (e.g. ozonation). The sand filter is constructed as a plurality of individual components that are in fluid flow communication. At least that uppermost individual component of the sand filter is removable for cleaning.

Description:
FIELD OF THE INVENTION  
       [0001]     This application relates to water treatment apparatus that utilize sand or other packed material as a filtration mechanism.  
       BACKGROUND OF THE INVENTION  
       [0002]     Several different systems are known for treating water. Typically, these systems employ filtration to remove particulate material from the water, and a purification step to kill bacteria viruses and the like in the water, such as treatment with ozone, peroxide or ultraviolet radiation. As a result of these steps, potable water may be produced.  
         [0003]     One treatment system that is known in the art is the sand filtration system. The systems are used treating water that is used in a house. Pursuant to the system, water is passed through and extended bed of sand. For example, the bed of sand may be three to four feet deep. One disadvantage the system is that it is and must periodically be cleaned or replaced. The sand is typically housed in a sealed container to prevent odors from the accumulated material that has been filtered from the sand from penetrating into a house. When the container is open to clean or replace the sand, these odors are released into the house. Further, replacing or cleaning the sand is a time-consuming job.  
       SUMMARY OF THE INVENTION  
       [0004]     In accordance with the instant invention, an improved sand filtration system has been developed. In accordance with one aspect of the instant invention, the bed of sand is provided in at least two, and preferably a plurality, of individual containers.  
         [0005]     The total length of the bed of sand that is employed in accordance with the instant invention is preferably for about 30 to about 48 inches. Typically, only about the top 8 inches of sand captures a substantial portion (e.g. over 90 percent and, in some cases, about 99 percent) of the material removed by the filtration process. Therefore, if the upper layer of sand is periodically cleaned or replaced, the remainder of the sand need not be replaced. In accordance with this embodiment of the invention, the bed of sand is divided into at least two portions. The first portion of the bed of sand that the water encounters (e.g. the top layer) is provided in a container that is removable from the rest of the apparatus. For example, the bed of sand may be provided in at least two containers that are removable mounted in a housing. Accordingly, when it is necessary to clean or replace the first portion of the bed of sand, the first portion of the bed of sand may be removed from the housing as a discreet element. Thus, a user need only remove one portion of the bed of sand reducing the mess that may be created in this process.  
         [0006]     In accordance with the instant invention, the remaining portion of the bed of sand may be provided in a plurality of discrete containers that are removably mounted in the apparatus so as to permit each portion of the bed of sand to be replaced as desired.  
         [0007]     Preferably, each container is sealed when removed from the apparatus. In this way, individual portions of the bed of sand may be replaced without releasing any odors into a house. The containers may be sealed upon removal from the apparatus by, for example, a check valve, ball valve or other closeable aperture that is sealed automatically upon the withdrawal of the container from the apparatus, such as an iris.  
         [0008]     In accordance with another embodiment of the instant invention, the filtered water is subjected to a purification step, such as treatment by ultraviolet radiation, or an oxidizer such as ozone. Preferably, the filtered water is subjected to ozonation.  
         [0009]     The treated water may be fed directly to in water supply system, such as the clean water supply to a house. Preferably, the treated water is stored so that a quantity of water is available for use at any particular time. In accordance with another embodiment of the instant invention, the water is stored in an unpressurized tank.  
         [0010]     In accordance with another embodiment of the instant invention, a biological material is added to the first portion of the sand, when that portion is replaced. A layer of biological and organic material [known in the art as schmutzdecke] forms on top of the sand during use of a sand filter. This layer provides a very effective filtration layer that enhances the performance of a sand filter The addition of biological material so as to expedite the formation of this biological layer of material beneficially enhances the filtration provided by the apparatus.  
         [0011]     It will be appreciated that each of these embodiments may be used individually in a water treatment apparatus according to the instant invention, or they may be combined in any particular combination. All such uses are within the scope of this invention. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0012]     For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made by way of example to the accompanying drawings, of the preferred embodiments of the present invention, in which:  
         [0013]      FIG. 1  is a is a schematic drawing of a first embodiment of a water treatment apparatus according to the instant invention;  
         [0014]      FIG. 2  is a schematic drawing of a second embodiment of a water treatment apparatus according to the instant invention;  
         [0015]      FIG. 3  is schematic drawing of a third embodiment of a water treatment apparatus according to the instant invention; and,  
         [0016]      FIG. 4  is an alternate embodiment of the treated water storage tank. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     The water treatment apparatus of the instant invention may be used to treat a portion, and preferably all, of the water that is provided to a house, apartment, cottage or other dwelling. Accordingly, the apparatus may be used to treat municipally treated water that is provided to a house, or well or lake water that is provided to a dwelling.  
         [0018]     Referring to  FIG. 1 , a water treatment apparatus  10  comprises a sand filter  12 , a purification chamber  14  and a storage tank  16 . The embodiment disclosed in  FIG. 1  utilizes municipally treated water. As such, the water is provided to sand filter  12  under pressure. Preferably, the water is depressurized to, for example, less than 20 psi and, preferably, less than 5 psi. By reducing the pressure of the system, the construction of the apparatus is simplified. In particular, the seals that required for the different elements, such as the individual containers of sand filter  12 , are simplified. In addition, the components of the system may be made from thinner materials. The pressure of the incoming water may be reduced by any means known in the art. Optionally, a pressure meter, such as metering valve and solenoid  18 , may be provided at any point in the system so as to monitor the internal pressure of the water supply.  
         [0019]     In accordance with the instant invention, sand filter  12  is divided into at least two containers  20  and, preferably, into a plurality of containers  20 . The water flows sequentially through each container  20  so that, after the water has passed through each container  20 , it has passed through the sufficient depth of sand to achieve the desired degree of filtration. As shown in  FIG. 1 , water inlet  22  is provided at the bottom of sand filter  12 . Accordingly, the water flows upwardly through sand filter  12 . However, as shown in  FIG. 2 , water inlet  22  may be provided at the top of the sand filter  12 . In the embodiment of  FIG. 1 , sand filter  12  comprises 3 containers  20 . In this embodiment, lower containers  21  are provided merely as a platform for containers  20  so as to raise first container  20  (which is positioned immediately above containers  21 ) to a level above the ground to facilitate the removal of first container  20 .  
         [0020]     By constructing sand filter  12  from a plurality of individual containers  20 , the sand may be replaced one portion at a time. Preferably, each container  20  holds an amount of sand that may be easily moved by a single person. Thus, to clean or removal the sand, each container  20  may be removed from apparatus  10  one at a time, or all at the same time, so as to clean or replace all of the sand. However, it will be appreciated that only one more of the upstream containers where the bulk of the filtration occurs may be replaced on a regular basis.  
         [0021]     Container  20  may be of any shape known in the art and typically has a bottom  24 , a top  26  and sidewalls  28  extending between bottom  24  and top  26 . Container  20  has a water inlet  28  and an outlet  30  so as to permit water to flow through sand  34  that is positioned in container  20 . A passageway  38  may be optionally provided to connect outlet  32  of one container  20  with inlet  30  of the container  20  that is immediately downstream. Alternately, the downstream end of the outlet  32  of one container  20  may matingly engage the upstream end of an inlet  30  of the adjacent downstream container  20 . Sand  34  may be retained in containers  20  by any means known in the art so as to prevent sand  34  from exiting container  20  with the flow of water therethrough. For example, in a preferred embodiment, a substrate  36  is provided in the bottom of each container  20 . The substrate may be a woven material such as woven polyethylene. The substrate has openings that are sufficiently large to permit water to flow upwardly, or downwardly, therethrough but sufficiently small to retain sand  34  in container  20 .  
         [0022]     Each container  20  may be provided in a housing that holds each container  20  in position. To remove a particular container  20 , the housing may be disassembled or may have access port so as to allow access to container  20 . Alternately, no exterior housing may be provided. Instead, may be containers  20  are mechanically linked to each other so as to define a structural unit.  
         [0023]     Preferably, each containing  20  is provided in apparatus  10  so as to be sealed upon removal from apparatus  10 . Accordingly, a closure member, such as valve  40 , may be associated with at least the inlet  30  or outlet  32  which is provided in bottom  24  of each container  20  so as to prevent any water in container  20  from flowing out to through the opening in the bottom  24  of container  20  when container  20  is removed from apparatus  10 . More preferably, a valve  40  is provided for each of inlet  30  and outlet  32  so that all of container  20  may be sealed upon its removal from apparatus  10 . The closure member may be a valve, iris or the like and may be either manually operated or automatically operated. Preferably, valve  40  is automatically operated upon the removal of container  20  from apparatus  10 , such as a check valve or the ball valve. Accordingly, when container  20  is removed from apparatus  10 , valve  40  will automatically operate prevent any water in container  20  from flowing out to through bottom  24 .  
         [0024]     After the water has passed through of sufficient amount of sand  34 , the water is next preferably subjected to a purification process. The purification process may be any known in the art to kill viruses and bacteria. The purification process may be oxidation or irradiation, such as with ultraviolet radiation. Preferably, the water is subjected to ozonation. Accordingly, in the embodiment of  FIG. 1 , a purification chamber  14  comprises an ozonation chamber. As shown in the embodiment of  FIG. 1 , an electronics module  42  is provided immediately above ozonation chamber  14 . It will be appreciated by those skilled in the art that the individual components included an electronics chamber  42  may be provided at any convenient location which is desired. In the embodiment of  FIG. 1 , electronics until  42  includes a container  44  containing a desiccant  46 . Container  44  has an inlet and outlet [not shown]. The outlet is in airflow communication with air pump  48 . Air pump  48  has an outlet that is an airflow communication with ozone generator  50 . Ozone generator  50  produces ozone, as air is passed there through. Ozone containing air exits generator  50  and passes to sparger  54  by means of passage  52 . The ozone containing gas bubbles through the water in chamber  14  and results in an off gas that may accumulate in a headspace at the top of chamber  14 . The off gas may exit container  14  by means of outlet  58 . The off gas then travels through passage  62  to ozone destructor  56 . Thereafter, and the air, from which the ozone has been removed, may be vented to that atmosphere.  
         [0025]     Subsequent to ozonation, the water may be fed directly into a household water supply system. In such a case, treated water outlet  66  may be connected to a water supply line for a house or a portion of a house or the like (such as via line  72 ). Alternately, as shown in  FIG. 1 , the treated water may be stored in a storage tank  16 . Storage tank  16  may be any storage tank known in the art. The dimensions and volume of storage tank  16  may be determined based on the design specifications of the apparatus.  
         [0026]     If apparatus  10  is operated under pressure, such as the pressure of a municipal water supply, then storage tank  16  may store the water under elevated pressure. In such an embodiment, the pressure in tank  16  may be sufficient to deliver the water to household supply line  72 . A pump  70  may optionally be provided to increase the pressure of the water to the desired level.  
         [0027]     In an alternate embodiment, storage tank  16  stores the treated water at a reduced pressure and, preferably, at about atmospheric pressure. The use of an atmospheric storage tank is beneficial since it simplifies the construction and maintenance of storage tank  16 . For example, storage tank  16  may be designed to hold a capacity of 40 or more gallons of water. At such dimensions, the cost of a storage tank that operates at an elevated pressure is substantial. In addition, additional design constraints are required to ensure that tank  16  maintains its dimensional integrity throughout the life of apparatus  10 . In this embodiment, as shown in  FIG. 1 , pump  70  is provided downstream from storage tank  16  so as to deliver water to domestic feed line up  72 .  
         [0028]     In another embodiment, the treated water may be fed through a post ozonation filter  62  prior to entering storage tank  16 . For example, as shown in  FIG. 1 , the treated water may be fed to post filter  62  via passageway  66 . Post filter  62  may be of any construction known in the art. If apparatus  10  operates under reduced pressure [i.e. below the pressure supplied by the municipal water supply system], then post filter  62  preferably comprises granular activated carbon  64 . In such an embodiment, post filter  62  is preferably positioned above storage tank  16  so as to permit the water to flow into storage tank  16  from post filter  62  by gravity feed, such as by passageway  68 .  
         [0029]     It will be appreciated that if the water in passageway  66  is at a sufficient pressure, then post filter  62  may be an extruded carbon filter. For example, apparatus  10  may operate an elevated pressure without a pressure reduction valve, such as metering valve  18 . Alternately, pump  70  may be provided at upstream of storage tank  16  so that water is delivered to apparatus  10  via pressurized supply line  74 . In such a case, post filter  62  may be positioned at any location which is desired, such as in storage tank  16 , as shown in  FIG. 2 , or exterior to, but adjacent the bottom of, storage tank  16 .  
         [0030]     In a further alternate embodiment, water may be delivered to apparatus  10  such as by a pump  76  [see  FIG. 3 ]. For example, the source of water to be treated it may be a well, in which case 0.76 would deliver water from the well to apparatus  10 . Alternately, a hand pump could be utilized to deliver water to the apparatus.  
         [0031]     During the operation of a sand filter, a layer of biological material tends to form of on top of the sand. This there typically contains bacteria that prey on harmful bacteria, such as those which comprise human pathogens. This layer is known in the art as the schmutzdecke. This layer enhances the filtration characteristics of a sand filter. One disadvantage of current sand filters is that it takes about three to four weeks for the schmutzdecke to form when a new filter is put into service, or when a sand filter is cleaned. In accordance with another embodiment of the instant invention, a cartridge of biological material may be provided. The biological material in the cartridge may be added to one are more containers  20  of sand when the container is placed into service. The biological material helps the formation, or accelerates the formation of the schmutzdecke. The cartridge may be provided as part of container  20 , such as in the lid thereof, so as to be positioned above the sand  34 . The cartridge may be pierced, or opened, by a handle provided exterior to container  20 . Thus, when container  20  is mounted in apparatus  10 , the cartridge may be opened to release the biological material without the user coming into contact with the biological material.  
         [0032]     In the alternate embodiment of  FIG. 4 , purification chamber  14  is positioned in storage tank  16 . Purification chamber  14  is positioned upstream of sand filter  12  and in fluid flow communication therewith via passage  78 . Post filter  62  is optionally provided downstream from purification chamber  14 . In this embodiment, purification chamber  14  is positioned in the upper portion of storage tank  16  so that water level  84  of storage tank  16  controls float valve  82  that is provided in passage  78 . In operation, as water is removed from storage tank  16 , the water level in storage tank  16  drops causing float  80  to drop thereby opening float valve  82  and causing water to enter purification chamber  14  for treatment. When the water level in storage tank  16  has been raised to the preset level, then float  80  causes float valve  82  to close passage  78  and stop the flow of water into purification chamber  14 . Post filter  62  and purification chamber  14  may be held in position by any means know in the art such as by being suspended from the lid of storage tank  16  via brackets  86 . Alternately, or in addition, a second float switch  88  may be provided on a bracket  90  and operatively connected to air pump  48  and ozone generator  50  to de-energize air pump  48  and ozone generator  50  when the water level rises to its preset level and the flow of water to purification chamber  14  is terminated.  
         [0033]     It will be appreciated that a water treatment apparatus in accordance with the instant invention may use one or more of the embodiments disclosed herein. It will be appreciated by a person skilled in the art that the various embodiment maybe combined to produce a number of different water treatment apparatus, each of which is within the scope of this disclosure.