Treatment of Arsenic, Heavy Metals, and Acidity Using a Mixed ZVI-Compost PRB

• Published in: Environmental science & technology Vol. 43; no. 6; pp. 1970 - 1976
• Main Authors: Ludwig, Ralph D, Smyth, David J. A, Blowes, David W, Spink, Laura E, Wilkin, Richard T, Jewett, David G, Weisener, Christopher J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.03.2009
• Subjects: Acidity; Analytical chemistry; Applied sciences; Arsenic; Arsenic - chemistry; Environmental Monitoring; Exact sciences and technology; Groundwater; Heavy metals; Hydrogen-Ion Concentration; Industrial Waste; Iron; Metals, Heavy - chemistry; Pilot Projects; Pollution; Remediation and Control Technologies; Soil - analysis; Soil Pollutants - chemistry; Sorption; Sulfur; USA, South Carolina, Charleston; Compost; XANES spectrometry; Arsenic; Arsenates; Zerovalent metal; Acidity; Plant leaf; Permeable reactive barrier; Phosphate fertilizer; Sulfates; Arsenites; Bound form; Heavy metal; Sorption; Decontamination; Surveillance; Lead; Water pollution; Ground water
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es802394p

A 30-month performance evaluation of a pilot permeable reactive barrier (PRB) consisting of a mixture of leaf compost, zero-valent iron (ZVI), limestone, and pea gravel was conducted at a former phosphate fertilizer manufacturing facility in Charleston, SC. The PRB is designed to remove heavy metals and arsenic from groundwater by promoting microbially mediated sulfate reduction and sulfide-mineral precipitation and arsenic and heavy metal sorption. Performance monitoring showed effective treatment of As, Pb, Cd, Zn, and Ni from concentrations as high as 206 mg L−1, 2.02 mg L−1, 0.324 mg L−1, 1060 mg L−1, and 2.12 mg L−1, respectively, entering the PRB, to average concentrations of <0.03 mg L−1, < 0.003 mg L−1, < 0.001 mg L−1, < 0.23 mg L−1, and <0.003 mg L−1, respectively, within the PRB. Both As(III) and As(V) were effectively removed from solution with X-ray absorption near edge structure (XANES) analysis of core samples indicating the presence of As(V) in oxygen-bound form and As(III) in both oxygen- and sulfur-bound forms. XANES solid phase sulfur analysis indicated decreases in the peak amplitude of intermediate oxidized sulfur species and sulfate components with increasing distance and depth within the PRB.