Q. Your expertise includes everything from hazardous waste remediation to drinking water treatment. What is your background?
A. My undergraduate and doctoral degrees are in chemical engineering, and my master’s is in biochemical engineering. I also did postdoctoral research in environmental microbiology. When oil prices went up in the 1980s, I worked for a company that researched nuclear fusion for energy production and researched microbial biofuel production. Then I focused on treatment of hazardous waste and drinking water. The interdisciplinary approach of studying microbiology, chemistry, and engineering gave me the foundation to work in many different fields.
In recent years, I have been researching innovative ways to address emerging contaminants, such as perchlorate—an oxidant found in rocket fuel, munitions, fireworks, and road flares. Perchlorate is an endocrine disrupting compound that can potentially cause serious health issues, and it is found in soil, groundwater, and drinking water.
Q. What new discoveries have you made for hazardous waste remediation?
A. Since 2003, I have been working to invent and develop gaseous electron donor injection technology (GEDIT), a novel bioremediation process to destroy contaminants in soil. This approach promotes remediation in situ since gases contact contaminants more effectively than liquids, causing bacteria to metabolize and destroy perchlorate and nitrate in soil, and preventing it from leaching into groundwater sources.
CDM Smith partnered with the U.S. Department of Defense Environmental Security Technology Certification Program and Aerojet-General Corporation to successfully demonstrate GEDIT, beating our 90-percent reduction goals for perchlorate and nitrate. Also, GEDIT is useful for treating multiple contaminants. It’s very exciting to identify a completely new technology to solve a serious problem.
Q. How does your work on hazardous waste remediation relate to drinking water treatment?
A. Many things we learn in one field can be applied to another field, but typically you have different groups of people working separately—and they don’t talk to each other. Even though biological treatment processes are well-established for hazardous waste and wastewater treatment, they have not been optimized for drinking water treatment. There are many tools that are virtually unknown in the drinking water industry that could be very beneficial.
The good news is that we are making big strides in biological drinking water treatment. I am currently working with the Water Research Foundation to produce a monitoring and control toolbox and guidance manual to help utilities with biological filtration. We know that the combination of biological, chemical, and physical treatment processes creates a powerful synergy that enhances filter performance, reduces energy demands, and produces high-quality water—and now utilities will have the tools they need to take advantage of these effects.
Q. What drives your research?
A. Every day we are using innovation and creativity to meet challenges. We’re using applied science to solve complicated problems that formerly had no solutions…and, it’s fun. I have had the opportunity to conduct workshops nationally and internationally about perchlorate treatment—a concern all over the world. I’ve also had the honor of collaborating with global agencies and experts. This collaboration gives me new perspectives and insights that drive innovation, which can result in more sustainable processes and solutions—whether it be for cities, industry, or governmental agencies. Biological filtration of drinking water and GEDIT are just two examples.
Pat Evans, Ph.D., has 22 years of experience in environmental process engineering, chemistry, and microbiology. He leads projects in environmental remediation, drinking water and wastewater treatment, and energy recovery. Dr. Evans also directs CDM Smith’s Bellevue Environmental Treatability Laboratory, and has three patents and one patent pending.