In gravity injection, small volumes of reagents are gravity-fed into injection well(s) over a longer application period. The distribution and dissipation of the reagents in the saturated zone is largely controlled by the site hydrogeologic conditions. The gravity injection approach may reduce some of risks associated with chemical oxidation technologies. Additionally, given its prolonged application period, the oxidants may be able to penetrate into more of the lower permeability soils to address contaminants in these areas. In both cases, multiple injection events, separated by extended periods of groundwater monitoring, may be required in order to approach cleanup objectives. Establishing which injection or application approach.
