Abstract: The present invention is a composite filter for use with recycling gray water. The filter is comprised of a housing containing a series of filters, a first depth filter, preferably made of cellulose fibers for removing particles and turbidity causing materials, a second depth filter, preferably made of cellulose and diatomaceous earth for removing additional particles and turbidity causing materials, an organics filter, preferably a carbon filter to remove organic material and an ion exchange material to remove dissolved ionic species such as salts, acids and the like.

Abstract: Ultrapure water containing less than 10 ppt total ions, other than hydrogen ion and hydroxide ion is produced by passing deionized water through a system comprising an ultrafiltration step, an oxidizing step where water is exposed to ultraviolet light and ion exchange step. The treated water is recirculated through the oxidizing step and the ion exchange step. Product water from the system can be recovered on a continuous basis so long as the ratio of volume of water circulated within the system to volume of water drawn from the system is at least 10 and preferably at least 20.

Abstract: An electrodeionization apparatus is provided for removing ions from liquids. Liquid to be purified is passed through depleting compartments containing mixed anion and cation exchange resin beads while a second liquid is passed through concentrating compartments free of ion exchange resin beads. Ions, under influence of an electrical potential, pass from the depleting compartments into the concentrating compartments through ion permeable membranes. A spacer for each depleting compartment is provided which retains the beads within the compartment, promotes even flow through the compartment and prevents plugging of the compartment inlet by the beads and external foulants.