HR: 0800h
AN: H21C-1036    [Abstracts]
TI: Determining the Influence of Groundwater Composition on the Performance of Arsenic Adsorption Columns Using Rapid Small-Scale Column Tests
AU: * Aragon, A R
EM: ararag@sandia.gov
AF: Sandia National Laboratories, PO Box 5800 MS 0750, Albuquerque, NM 87185 United States
AU: Siegel, M
EM: msiegel@sandia.gov
AF: Sandia National Laboratories, PO Box 5800 MS 0750, Albuquerque, NM 87185 United States
AB: The USEPA has established a more stringent drinking water standard for arsenic, reducing the maximum contaminant level (MCL) from 50 $\mu$g/L to 10 $\mu$g/L. This will affect many small communities in the US that lack the appropriate treatment infrastructure and funding to reduce arsenic to such levels. For such communities, adsorption systems are the preferred technology based on ease of operation and relatively lower costs. The performance of adsorption media for the removal of arsenic from drinking water is dependent on site-specific water quality. At certain concentrations, co-occurring solutes will compete effectively with arsenic for sorption sites, potentially reducing the sorption capacity of the media. Due to the site-specific nature of water quality and variations in media properties, pilot scale studies are typically carried out to ensure that a proposed treatment technique is cost effective before installation of a full-scale system. Sandia National Laboratories is currently developing an approach to utilize rapid small-scale columns in lieu of pilot columns to test innovative technologies that could significantly reduce the cost of treatment in small communities. Rapid small-scale column tests (RSSCTs) were developed to predict full-scale treatment of organic contaminants by adsorption onto granular activated carbon (GAC). This process greatly reduced the time and costs required to verify performance of GAC adsorption columns. In this study, the RSSCT methodology is used to predict the removal of inorganic arsenic using mixed metal oxyhydroxide adsorption media. The media are engineered and synthesized from materials that control arsenic behavior in natural and disturbed systems. We describe the underlying theory and application of RSSCTs for the performance evaluation of novel media in several groundwater compositions. Results of small-scale laboratory columns are being used to predict the performance of pilot-scale systems and ultimately to design full-scale systems. RSSCTs will be performed on a suite of water compositions representing the variety of water supplies in the United States that are affected by the new drinking water standard. Ultimately, this approach will be used to carry out inexpensive short-term pilot studies at a large number of sites where large-scale pilots are not economically feasible.  Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.
DE: 1806 Chemistry of fresh water
DE: 1831 Groundwater quality
DE: 1030 Geochemical cycles (0330)
DE: 1065 Trace elements (3670)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting