SITE REMEDIATION AND
EMERGENCY RESPONSE NEWSLETTER
October 2012
No. 169
Activated Carbon Amendments for In Situ Stabilization of Contaminated Sediments –Technology Now Ready for Use
Research sponsored by the Department of Defense (DoD) has advanced the use of activated carbon (AC) for contaminated sediment site management from the lab and demonstration/validation stages to full-scale remedial applications.
AC can be applied to contain contaminated sediments in place. It can replace or augment other approaches such as dredging and capping. The Strategic Environmental Research and Development Program (SERDP) and the Environmental Security Technology Certification Program (ESTCP) of DoD funded development of this technology and note that it “has moved into the mainstream ‘tool box’ for contaminated sediment remediation.”
Activated carbon has long been used to remove organic contaminants from water. It works by stripping and tightly binding organic contaminants such as polychlorinated biphenyls (PCBs) and pesticides from the water. The SERDP-funded work demonstrated that adding precise doses of AC into sediments has the same effect. Organic contaminants are bound up and are then not available for uptake into organisms. Additions of as little as 2 percent AC resulted in reductions of between 10-fold and 100-fold in PCB uptake into marine organisms.
AC floats, so one of the early ESTCP-funded approaches was to formulate the carbon into both a pelletized form that would sink and one that could be applied using conventional equipment to achieve an even distribution on the sea floor. The pellet dissolves and releases the AC into the contaminated sediments.
Completed or ongoing demonstrations of this AC technology at DoD sites have included the Army's Aberdeen Proving Ground, Hunters Point Naval Shipyard, Naval Air Station Dallas, and the Puget Sound Naval Shipyard.
Remediation of contaminated sediments using AC is now being used in many bodies of water, including rivers, lakes, wetlands, and deeper water in active channels and piers. DoD points out that sites that have used AC as part of a remedy or are considering doing so include the Grasse River in New York, the Lower Duwamish Waterway in Washington, the Willamette River in Oregon, and two sites in Norway.