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TREATMENT OF ARSENIC AND METALS IN GROUND WATER USING A COMPOST/ZVI PRB
Citation:
LUDWIG, R. D., D. G. JEWETT, ANN AZADPOUR-KEELEY, AND F. P. BECK. TREATMENT OF ARSENIC AND METALS IN GROUND WATER USING A COMPOST/ZVI PRB. Presented at Remediation Technologies Development Forum (RTDF) PRB Action Team Meeting, Albuquerque, NM, October 26 - 27, 2004.
Impact/Purpose:
To inform the public.
Description:
A pilot permeable reactive barrier (PRB) consisting of a mixture of 30% yard waste compost, 20% zero-valent iron (ZVI), 5% limestone and 45% pea gravel by volume was installed at a former phosphate fertilizer manufacturing facility in Charleston, S.C. in September 2002. The pilot PRB, measuring 27 ft in length, 6 ft in width, and 12 ft in depth, is designed to treat arsenic, heavy metals, and acidity in ground water entering a tidal marsh by promoting microbially mediated sulfate reduction and subsequent sulfide precipitation. Five rounds of performance monitoring spanning a period of 18 months have been conducted at the site since installation of the pilot PRB. The PRB is thus far effectively treating arsenic and heavy metals in the ground water. Arsenic is being treated from concentrations of up to 126 mg/L in up gradient monitoring points to average concentrations of less than 0.04 mg/L within the PRB. Lead and cadmium are being treated from concentrations of up to 3.23 mg/L and 2.10 mg/L, respectively in up gradient monitoring points to average concentrations of less than 0.009 mg/L and 0.003 mg/L, respectively within the PRB. Alkalinity in the ground water increases from less than 0 mg/L in the up gradient ground water to up to 630 mg/L as CaCO3 within the PRB and in the process converts ground water from a net acid producing potential to a net acid consuming potential.