Biotechnology Advancements in Anaerobic Benzene Bioremediation


Benzene is a known carcinogen and a widespread pollutant arising from releases of petroleum products into the environment. Anaerobic bioremediation presents a cost-effective solution for plume control and cleanup of benzene at anoxic sites, but the liklihood of bioremediation success has generally been challenging to predict. Recent research advances suggest that in situ anaerobic benzene biodegradation is largely controlled by the abundance of anaerobic benzene degrading microbes, which are often in concentrations too low for rapid and effective bioremediation. To overcome these microbial limitations, a novel bioaugmentation culture, called DGG-BTM, has been developed for anaerobic treatment of benzene. This mixed microbial consortium contains a chief benzene degrader (Deltaproteobacteria ORM2) as well as other bacteria and methanogenic Archaea. The ORM2 benzene degrader has been observed in-situ at some benzene-contaminated sites, and can can be tracked using quantitative molecular genetic tests. In laboratory treatability studies, ORM2 bioaugmentation with DGG-BTM increased benzene bioremediation success by 70%, relative to natural attenuation and biostimulation alone. Based on successful laboratory studies, bioaugmentation field pilot testing is planned for later this year. Current investigations now aim to uncover whether anaerobic bioremediation of other hydrocarbon contaminants, such as toluene, ethylbenzene, and xylene, are also correlated to the abundance of requisite microorganisms. Overall, bioaugmentation has significant potential to make anaerobic BTEX bioremediation more efficient and cost-effective resulting in more petroleum hydrocarbon contamianted sites being cleaned up.

The Presenters:

Courtney Toth

Dr. Courtney Toth is a Postdoctoral Fellow in the Department of Chemical Engineering and Applied Chemistry at the University of Toronto. She holds a Ph.D. in Environmental Microbiology from the University of Calgary and specializes in hydrocarbon bioremediation. Her research has contributed to the understanding of how anaerobic microorganisms metabolize different hydrocarbon classes, including BTEX, PAHs, and alkanes. Today, Dr. Toth is applying this knowledge to develop novel treatments for hydrocarbon contaminants in anoxic environments. Courtney has received several awards, including a Mitacs Fellowship as part of a nearly $3-million public-private collaboration with SiREM (led by Dr. Elizabeth Edwards and Sandra Dworatzek).

Sandra Dworatzek

Ms. Dworatzek is a Principal scientist at SiREM and an environmental microbiologist with advanced technical experience in laboratory treatability studies. Over the past 24 years she has conducted and overseen numerous bench-scale studies examining enhanced in situ remediation in groundwater. She has specific technical experience in the design of laboratory treatability studies, the scale up of growth of anaerobic microbial cultures for bioaugmentation laboratory and field pilot tests, and evaluation of aerobic and anaerobic bioremediation, zero valent iron and chemical oxidation technologies in the laboratory.