Containment measures are often performed to prevent, or significantly reduce, the migration of contaminants in soils or ground water. Containment is necessary whenever contaminated materials are to be buried or left in place at a site. In general, containment is performed when extensive subsurface contamination at a site precludes excavation and removal of wastes because of potential hazards and/or unrealistic cost.

The main advantage of containment methods is that they can prevent further migration of contaminant plumes, and allow for contaminant reduction at sites where the source is undetermined, inaccessible, or where long term remedial actions are being developed. Unlike ex situ treatment groups, containment does not require excavation of contaminated soils, which leads to increased costs from engineering design of equipment, possible permitting, and material handling. However, these treatments require periodical inspections for leaks, ponding of liquids, and corrosion. Additionally, ground water monitoring wells, associated with the treatments, need to be periodically sampled and monitored.

Available containment technologies include physical/biological barriers and deep well injection. These processes are discussed in Section4. Completed containment for ground water, surface water, and leachate projects are shown in Table 3-16.