Commercially available drinking water filtration devices, such as pitchers or water dispensers from Pur and Brita, use containers which are arranged into two sections. A top section holds water before it is filtered, and a bottom section hold the filtered water. To use one of the devices, a replaceable carbon cartridge filter is placed in an approximately round hole in a barrier which separates the container into two approximately equal volumes. The two volumes are stacked vertically. Water is poured into the upper volume and gravity draws the water through the filter to the lower section. Drinking water is then drawn from the lower section.
Unfortunately, the devices are less than 50% volumetric efficient. That is, less than 50% of the total interior volume of the container is available for holding the filtered liquid. This is primarily because the holding volume for the unfiltered water is the same size as that of the holding volume for the filtered water, and the filter itself also takes up interior volume. Another shortfall of the commercially available filtration pitchers and water dispensers is that the design for their intended use, i.e. inside a refrigerator, makes them too fragile for many applications such as filtering drinking water at construction sites. Yet another shortfall is the limitation of the daily filtering capacity of the replaceable carbon filters. The commercially available carbon filters are often limited to filtering only a few gallons of water per day, and may take several minutes to filter even a single gallon of water.
Other water containers, such as the widely-used 10-gallon water cooler from Igloo, are well suited to rugged environments. Due to their size, these large water coolers are often filled from garden hoses or outdoor faucets, which may not produce the best-tasting or cleanest water. Filling a 10-gallon water cooler using filtered water from a Pur or Brita pitcher or dispenser is impractical in many situations, due to the filtration time and the need to cycle several full pitchers to fill a single 10-gallon cooler. Ironically then, the rugged environments in which carbon filter cartridges may be the most appreciated are the ones lacking a cost-effective system for using the filters in a ubiquitous container.