Soils contaminated with creosote and diesel fuels at the Benfield Industries Site in Waynesville, North Carolina were remediated using a modified biopile treatment technology. Soil was excavated, amended with straw and manure, and formed into windrow configurations in a land treatment unit (LTU). An excavator was used to lift, mix, aerate, and redistribute the soil in the windrows. Confirmatory sampling was performed for baseline conditions and then monthly to document the progress of biological treatment. Similarly, the LTU was sampled initially for baseline biological monitoring concentrations conditions, and then either weekly or monthly until treatment was complete. Soil was classified as successfully treated when analytical results demonstrated that remediation goals had been met or that biodegradation had ceased to reduce polycyclic aromatic hydrocarbon (PAH) levels. If PAHs were above the remediation goals, soils were sampled for Toxicity Characteristic Leaching Procedure (TCLP) analysis. Such soils were considered successfully treated if TCLP extract results contained contaminant concentrations that were at or below their respective groundwater remediation levels and North Carolina groundwater quality standards. The remediation goal for benzo(a)pyrene was not changed. Soil that failed to meet the benzo(a)pyrene target was buried by at least one foot of clean fill.
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