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

Abstract

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 µg/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. 2017

Regenerating an Arsenic Removal Iron‐Based Adsorptive Media System, Part 2: Performance and Cost

“…The TPWD arsenic removal system consists of two 5 ft-diameter adsorption vessels in parallel (tanks A and B); detailed design information for the system can be found in the first article of this series (Sorg et al 2017). The TPWD arsenic removal system consists of two 5 ft-diameter adsorption vessels in parallel (tanks A and B); detailed design information for the system can be found in the first article of this series (Sorg et al 2017).…”

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In the first article (Sorg et al 2017) in this two-part series, results of three regeneration studies were presented. That study highlighted a three-step regeneration process of media backwash, caustic regeneration, and acid neutralization conditioning to strip arsenic and other contaminants from exhausted granular ferric oxide (GFO) media 1 in the arsenic removal treatment system at the Twentynine Palms Water District (TPWD) in California.

This article, the second of two, presents performance data on the treatment system to remove arsenic following the three regeneration studies (detailed in Sorg et al 2017) and the two subsequent studies conducted by TPWD.

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“…

In the first article (Sorg et al 2017) in this two-part series, results of three regeneration studies were presented. The TPWD arsenic removal system consists of two 5 ft-diameter adsorption vessels in parallel (tanks A and B); detailed design information for the system can be found in the first article of this series (Sorg et al 2017). The authors also look at the estimated cost savings of each regeneration over media replacement.

MATERIALS AND METHODS

Arsenic treatment system and operation.

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“…In the first article (Sorg et al 2017) in this two-part series, results of three regeneration studies were presented. That study highlighted a three-step regeneration process of media backwash, caustic regeneration, and acid neutralization conditioning to strip arsenic and other contaminants from exhausted granular ferric oxide (GFO) media 1 in the arsenic removal treatment system at the Twentynine Palms Water District (TPWD) in California.…”

“…This article, the second of two, presents performance data on the treatment system to remove arsenic following the three regeneration studies (detailed in Sorg et al 2017) and the two subsequent studies conducted by TPWD. The authors also look at the estimated cost savings of each regeneration over media replacement.…”