LANDFILL BARRIER DESIGN: A CASE STUDY ON ACCELERATED NATURAL ATTENUATION

摘要

Oxygen Release Compound (ORC?) was injected into the shallow groundwater to accelerate natural attenuation and remediate low-level concentrations of volatile organic compounds (VOCs) at a landfill. A remediation system consisting of dual parallel treatment trenches was installed upgradient of the impacted wells. Each trench was keyed into a shallow hardpan for treatment of the entire vertical section along the groundwater flow path. The trench closest to the landfill received a one-time slurry application of ORC?. The second trench was equipped with a two-foot (0.61 m) diameter perforated drainage pipe surrounded by gravel. Multiple application wells were placed within the second trench for long term ORC? filter sock application. Concentrations of VOCs decreased 20-fold seven months after treatment and remain below drinking water standards in the downgradient monitor well. Monitoring of dissolved oxygen in downgradient wells did not indicate a significant increase after injection. The lack of apparent response may be due to oxygen being consumed upgradient of the monitor wells and/or the general anaerobic background conditions of the aquifer. In addition, specific conductance values have been reduced to site background levels and concentrations of 1,1-dichloroethane, a less aerobically degradable compound, have been reduced. Monitoring of site remediation performance is ongoing.