You are here:
Biological Oxidation of Ammonia and Arsenic in Pilot-scale Rapid Sand Filters
Citation:
White, C., J. Popovici, AND D. A. LYTLE. Biological Oxidation of Ammonia and Arsenic in Pilot-scale Rapid Sand Filters. Presented at EPA Workshop on Small Drinking Water Systems: Compliance Strategies, Cincinnati, OH, August 10 - 12, 2010.
Impact/Purpose:
To inform the public.
Description:
The removal of ammonia from source water entering a drinking water distribution system is desirable, as excess levels have been correlated with nitrification, chlorine demand, corrosion, and biological re-growth. Several technologies exist to remove ammonia with recent interest in biological processes. The objective of this study was to design, operate, and evaluate the oxidation of ammonia and arsenic in pilot-scale, biologically active, rapid sand filters. Two pilot filters were seeded with backwash from a full-scale biologically active filter and ammonia oxidation observed approximately 40 days later. The filters were loaded with, and fully oxidized, approximately 1.3 mg/L ammonia-nitrogen and 95 g/L arsenic at 3.5 gpm/sqft (EBCT 7.6 min). Backwash water had a direct effect on nitrification recovery. This technology proved to mitigate excessive source water ammonia both reliably and efficiently as well as serve as a chemical-free method of arsenic oxidation for subsequent arsenic removal via sorption.