US Patent 7427355 Water treatment unit for bottle or pitcher

A water treatment unit for positioning in a sport bottle or container for treating water includes a prefilter section, a pretreatment section, a treatment section and a post treatment section. A first chamber in the pretreatment section contains a first treatment medium which comprises at least one loose particulate medium through which the water to be treated flows in a vertical upward direction during treatment to lift the medium. A second chamber in the treatment section contains a second treatment medium through which the treated water flows in a radial horizontal direction during treatment. And a third chamber in the post treatment section contains a third treatment medium through which the water to be treated flows during treatment.