Project Summary
Polychlorinated biphenyls (PCBs) are one of the most problematic of legacy contaminants.
Persistent and mobile in the environment, PCBs are largely ubiquitous in depositional sediments of
aquatic systems in industrial regions of the United States. Their relatively high toxicity and
bioaccumulation potential cause elevated risk to both human and ecological receptors. As such,
PCBs are often the primary risk driver at impacted sediment sites. Common practices for
remediating PCB-impacted sediments are costly, often involving the physical removal of surficial
sediments, capping the sediments or dredge depression with a multi-layered engineered cap, and
disposal of the contaminated sediments in a confined landfill.
An emerging strategy for effectively removing PCBs from sediments in-situ is the use of bioamended
activated carbon (AC), which inoculates AC pellets with enriched cultures of PCB-degrading
microbes. The co-investigators of this proposed research have performed the fundamental research
behind the use of bioamended AC for remediation of PCBs from sediment and have developed and
patented commercially-viable methods for growing, inoculating, and delivering the inoculated AC
pellets to sediments. However, during the performance of pilot-scale studies using the bioamended
AC, two factors that would limit the ready use of this technology for large, multi-acre sites were
identified: 1) the large-scale growth, storage, and transport of anaerobic PCB degrading bacteria,
and; 2) large-scale methods for inoculating AC pellets during application. The proposed research
aims to address these limitations.
The proposed research will test methods of culturing these organisms using time-release growth
media, and develop and test storage vessels that maintain optimal environmental conditions for the
long-term viability of the anaerobic organisms. These advances will ultimately allow for the delivery
of large volumes of PCB degrading microorganisms for large-scale projects. The proposed research
will also develop and test methods for the continuous, uniform inoculation of high volumes of AC
pellets with the PCB-degrading microorganisms, which will allow for cost-effective application at
multi-acre PCB-impacted sites. Coupled together, the proposed research is anticipated to result in a
direct transfer of this technology from pilot-scale to full commercial viability.
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