David Major Principal Geosyntec Consultants Inc.

Dr. David Major, Ph.D., is a Principal of Geosyntec Consultants Inc., Associate Editor of Ground Water Monitoring and Remediation, and an Adjunct Professor at the Department of Chemical Engineering and Applied Chemistry, University of Toronto and Department of Earth Sciences, University of Waterloo (UW). He has worked for Geosyntec Consultants Inc. in Guelph, Ontario, Canada since 1998. David has over 20 years experience working with clients, researchers, and regulators to develop practical biological and chemical solutions to remediate contaminated sites. He has helped various researchers to develop and commercialize new environmental technologies such as zero-valent iron (ZVI) permeable reactive barriers, molecular biomarkers, and bioaugmentation cultures. David was recently inducted into the Space Hall of Fame® in 2007 in recognition for his role in commercializing NASA’s Emulsified ZVI to treat DNAPLs. He received one of 50 Science’s Alumni of Honor Awards from the University of Waterloo, in celebration of 50 years of success and accomplishments of UW alumni and the university. David also serves on various national scientific and regulatory advisory boards. He served a member of the U.S. EPA Remediation Technologies Development Forum, served on a U.S. EPA Expert Panel to address the benefits of partial source treatment of DNAPLs, and on the U.S. National Research Council Committee on Geological and Geotechnical Engineering in the New Millennium. He has been an active member of the Interstate Technology and Regulatory Council (ITRC) since 1996. He co-developed and taught two ITRC courses (monitored natural attenuation [MNA] and accelerated anaerobic bioremediation of chlorinated solvents) and is currently an instructor on ITRC's BioDNAPL training course. He is also on the Steering Committee of the Sustainable Remediation Forum (SuRF) David earned his bachelor's and master’s of science, and doctoral degrees in biology from the University of Waterloo, Waterloo Ontario in 1981,1984, 1987 respectively.

Presentation Description
The Costs and Benefits of Combining Remedies - When to Combine or Not to Combine - That is the Question!
Unfortunately, single technology cleanups of chlorinated solvent contaminated sites to typical regulatory criteria are rare, while the benefits of partial source depletion remain uncertain and will depend on site specific conditions. Combining technologies has occurred out of frustration or desperation, or from a true interest that mixed remedies may be the solution to this dilemma. Is it? When should you stop one action and switch to another, and how will you know? How will you assess source treatment progress, or should you just change your remedial goals and expectations?

I will briefly summarize the performance of innovative and existing source treatment technologies, and the potential synergistic/antagonistic effects between them. Given that "biological polishing" is often considered the follow on treatment after aggressive source treatment, I will focus on a case study where we investigated the combination of a more aggressive ISCO treatment followed by biological polishing to illuminate how different metrics could be used to assess the remediation sequence, and when to switch from one technology to another.