Granular activated carbon (GAC) pressure filters from WesTech Engineering help remove low-molecular-weight contaminants from aqueous solutions. They help remove dissolved organic compounds responsible for poor taste and odor in drinking water and chlorine from industrial waters. When used as pretreatment equipment, they can prolong the life and efficiency of demineralizing ion-exchange resins and reverse osmosis membranes. They use a pressure vessel, typically with a conical underdrain for GAC media replacement. They are sized according to the contact time required for contaminant removal and desired media replacement frequency. Filter piping and valving for multiple units can be arranged to change flow paths between parallel, series (lead/lag or daisy chain) or single-unit flow patterns. Filters are typically backwashed upon new media installation, and the media usage front is then monitored via sample taps to allow for anticipation of media replacement. 801/265-1000; www.westech-inc.com.