Regenerating an Arsenic Removal Iron-Based Adsorptive Media System, Part 1: The Regeneration Process

Adsorptive media technology is frequently used by small water systems to remove arsenic because of its simplicity and efficiency. Current practice is to replace the media when it no longer reduces arsenic below the maximum contaminant level of 10 mu g/L that the US Environmental Protection Agency has set for drinking water. Media replacement typically accounts for approximately 80% of the total operational and maintenance costs. One potential option to reduce the cost is onsite regeneration and reuse of the media. To evaluate the regeneration option, three consecutive regeneration studies were conducted on a full-scale adsorptive media system. This article, the first of a twopart series, describes the regeneration process and its efficacy in stripping arsenic and other contaminants from exhausted media. Study results found that a threestep regeneration process of media backwash, caustic regeneration, and acid neutralization conditioning proved effective for stripping arsenic and other contaminants from the exhausted media.