t. Development of environmentally benign approaches to remediation of metal-contaminated soils and sewage
sludges are needed to replace currently used techniques of either landfilling or metal extraction using caustic or toxic
agents. We report results from four application technologies that use a metal-chelating biosurfactant, rhamnolipid, for
removal of metals or metal-associated toxicity from metal-contaminated waste. The four applications include: 1) removal
of metals from sewage sludge; 2) removal of metals from historically contaminated soils; 3) combined biosurfactant/phytoremediation
of metal-contaminated soil; and 4) use of biosurfactant to facilitate biodegradation of the organic component
of a metal-organic co-contaminated soil (in this case the biosurfactant reduces metal toxicity). These four technologies
are nondestructive options for situations where the final goal is the removal of bioavailable and leachable metal contamination
while maintaining a healthy ecosystem. Some of the approaches outlined may require multiple treatments or
long treatment times which must be acceptable to site land-use plans and to the stakeholders involved. However, the endproduct
is a soil, sediment, or sludge available for a broad range of land use applications.