Evaluating the Efficacy of Bioaugmentation for In-Situ Treatment of PCB Impacted Sediments

Abstract

The objective of the project was to demonstrate and validate a recently developed in-situ treatment for degrading polychlorinated biphenyls PCBs in contaminated sediments under field conditions. The innovative aspect of the technology is the application of activated carbon pellets as a solid substrate for 1 delivery of microorganisms into sediments and 2 sequestration and concentration of hydrophobic PCBs in close proximity to the PCB transforming bacteria. Both anaerobic halorespiring and aerobic PCB degrading bioamendments were mass cultured, transported to a site and delivered through a water column to sediments without loss of viability. Treatment with the bioamendment mixture reduced the mean total PCB concentration by an average of 52 percent and the aqueous PCB fraction by 95 percent after 13.5 months. Costs of the treatment were less than thick caps and dredging and the approach is uniquely suited to treat ecologically sensitive and difficult to reach areas.