Patent ID: 7455774

Claim:
An agent for decontaminating soil, groundwater or sediment contaminated with hexavalent chromium, said decontaminating agent comprising: ferrous iron in a hexavalent chromium decontaminating effective amount; and a microbial biostimulant of at least one member selected from the group consisting of yeast extract, inactive yeast, active yeast and peptone in an amount effective for propagation and activation of indigenous hexavalent chromium reducing microorganisms and indigenous iron reducing microorganisms, said agent acting in cooperation with indigenous hexavalent chromium reducing microorganisms present in said contaminated soil, groundwater or sediment to chemically and biologically reduce hexavalent chromium to trivalent chromium, and said agent acting in cooperation with indigenous iron reducing microorganisms present in said contaminated soil, groundwater or sediment to regenerate ferrous iron oxidized by chemical reduction of said hexavalent chromium.