Phil Dennis to Present on Bioaugmentation at the AEHS Foundation International Conference

Phil Dennis will speak at the Association for Environmental Health and Sciences (AEHS) Foundation International Conference on Soil, Water, Energy, and Air in San Diego, California, on March 19 and 20, 2024. He will lead the workshop, “Application of Molecular Biological Tools to Assess Biological Processes at Contaminated Sites,” at 6:30 p.m. PDT on March 19. Phil will lead the workshop with Stephanie Fiorenza, Ph.D. (Arcadis) and Sam Rosolina (Microbial Insights).

He will also present “Unlocking the Potential of Anaerobic Bioaugmentation Cultures for Complete BTX Remediation: Field Applications and Regulatory Approvals” at 4:00 p.m. PDT on March 20. Phil’s coauthors for the presentation are Sandra Dworatzek and Jennifer Webb (SiREM) and Elizabeth Edwards, Nancy Bawa, Shen Guo, and Courtney Toth (University of Toronto).

Phil has more than 30 years of experience researching and managing molecular biology, microbiology, and environmental remediation laboratories. He is a founding member of SiREM and, as a Principal Scientist, manages research and development and directs molecular genetic testing services. Phil focuses on analyzing and characterizing environmental microbial communities using molecular genetic methods.

For more than three decades, the AEHS Foundation International Conference has united environmental professionals, fostering a sense of community, igniting groundbreaking collaborations, and addressing the evolving needs of the environmental field. The event offers platform and poster sessions, focused workshops, exhibit booths, and social and networking events.

AEHS is a nonprofit professional organization that fosters communication and cooperation among professionals concerned with assessing, cleaning up, and protecting soil, sediment, and water.

As remediation sites increase in complexity, the need for accurate characterization of a site’s conditions as to its physical, chemical, and biological nature also increases. The monitoring and evaluation of remediation also requires a complete understanding of attenuation processes. The application of physical and chemical testing procedures is widely understood and performed. In contrast, evaluations targeting biological processes via molecular biological tools (MBTs) are much less commonly performed, and as result, most conceptual site models are incomplete. The purpose of the newly published ASTM Standard Guide for Application of Molecular Biological Tools to Assess Biological Processes at Contaminated Sites (ASTM E3354-22) is to provide an overview of MBTs and present a framework through which project managers and other remediation professionals can select and apply MBTs at their sites. This is the first comprehensive guidance document on MBTs produced specifically for site stakeholders. The instructors are industry veterans and members of the team that developed the standard guide; they will lead participants through the key findings and recommendations of the standard guide. Real-world scenarios and case studies presented will be used to guide participants through selection, planning, deployment, sampling, quality control, and interpretation of MBT data to inform practitioners in the best use of these powerful technologies.

Anaerobic bioaugmentation cultures for benzene, toluene, and xylene (BTX) have been identified, investigated, and demonstrated to completely degrade BTX into carbon dioxide and methane. This occurs in the absence of oxygen and is what makes these cultures unique and useful for anoxic field applications where alternative (aerobic) remediation approaches may be impracticable or impossible to implement. The cultures, collectively referred to as DGG-PlusTM include a methanogenic benzene culture (DGG-BTM), toluene-degrading culture (DGG-TTM), and an o-xylene degrading culture (DGG-XTM) originally developed at the University of Toronto. The microorganisms responsible for BTX transformation have been identified. These cultures have been assessed through Environment Canada’s New Substance Notification program, applied at both pilot and full scales in the US and Canada and can be used at sites across Canada and globally.

Results from laboratory studies demonstrated enhanced benzene, toluene, and o-xylene biodegradation rates with DGG-PlusTM bioaugmentation and provided information to aid in field pilot-test design. One field pilot-test performed in November 2019 at a site in Saskatchewan initially included three injection points, with four additional points added in September 2021. Benzene degradation rates were accelerated in situ through bioaugmentation as observed in corresponding treatability studies. Additional field applications (in Canada and the US) where bioaugmentation with the DGG-Plus culture occurred are also being monitored.

These first-to-field projects provide a better understanding of dosing requirements, time frames for obtaining results, and ranges of conditions over which the cultures are effective. As with chlorinated solvents, bioaugmentation for BTX compounds has the potential to decrease remediation time frames and increase the range of sites to which bioremediation is applicable, providing a much-needed, cost-effective alternative for BTX remediation in groundwater.

This presentation will summarize data from regulatory approvals and highlight several field applications (both pilot and full-scale) where these anaerobic cultures were used.