When hazardous waste has been buried in the ground a layer of soil may need to be removed before the waste is excavated. This layer, called overburden, is set aside and is later replaced in its original location. Contaminated materials are then dug up and loaded onto trucks for hauling. After it is cleaned up, excavated soil may be returned to its original location for use as backfill. Soil in the walls and bottom of the excavated area is tested to ensure that all contamination has been removed.
Excavation proceeds until cleanup goals are met.
Excavation of hazardous waste or contaminated materials must be carefully planned to make sure contamination doesn t spread to clean areas of the site. For example, once excavation equipment is in a contaminated area, it must stay there until the work is completed, then thoroughly cleaned and decontaminated prior to leaving the site. In the event that contaminants have seeped into the groundwater, additional treatment may be necessary. Hazardous wastes can generally be excavated without exposing people near the site to contamination. Wastes can be removed for further treatment or disposal at an approved landfill.