Expert Interview 

Michael Kovacich, CPG, CP

Michael Kovacich graduated from Eastern Michigan University in 1991 with a major in geology and a minor in biology. He received his Master of Science in Earth Science from Western Michigan University in 1999, specializing in contaminant hydrogeology and coastal processes.

Mr. Kovacich began working in the environmental consulting industry in 1994 and joined Tetra Tech in 1995. He has more than sixteen years of professional experience applying hydrogeological principles to municipal groundwater supply, landfills, environmental investigations, and remediation. He has extensive experience completing large-scale site investigations at sites with a wide range of contaminants including heavy metals, brines, chlorinated solvents, PCBs, and refined petroleum products. He has successfully applied remedies such as soil vapor extraction to recover fugitive landfill gas and chlorinated solvents, soil flushing to recover DNAPL, ex-situ thermal soil desorption, soil excavation and off-site disposal, in-situ aerobic and anaerobic bioremediation.

Q:   Your job title is Hydrogeologist – what do you do?
A:  As a hydrogeologist, my focus is groundwater. There are two primary sides to the business of groundwater: how to clean it up, and how to find sufficient quantity and quality for drinking water supply. I’ve worked in both the environmental restoration side and water supply side.

Q:  Speaking of environmental work, Tetra Tech recently worked on a biobarrier project in Connersville, Indiana, that successfully addressed trichlorethelyene (TCE) contamination in a groundwater plume. How big of a problem is TCE contamination in the United States?
A:  In the 1950s through the 1990s, TCE was considered by many to be a “miracle degreaser.” So whenever a manufacturing machine or a manufactured part was being cleaned or prepared for painting, TCE was often used. This compound, along with other solvents, was used at virtually every tool and dye shop across the country and every major manufacturing facility. And of course dry cleaners were using PCE to take care of that nasty ring-around-the-collar.

So how big of a problem is TCE contamination? Exposure to TCE can have significant adverse health effects and is considered a known carcinogen in the State of California. Almost every industrial property we’ve ever investigated we’ve found TCE. It’s not always in concentrations that require immediate action, but it is often there. And it can volatilize off of groundwater into the indoor air of an office or house if the soil conditions and building location are conducive.

Q:  Tell us about your unique approach at Connersville.
A:  Our client did not want to tackle this problem with the traditional pump-and-treat approach. Pump-and-treat has been the preferred approach for sites like Connersville for over 20 years. Extraction wells are installed to capture the impacted groundwater and bring it to the surface, then the groundwater is usually treated with an air stripper or activated carbon. TCE can be stripped from the water stream because it’s so volatile, and once it is in the vapor phase, you can use carbon or a catalytic oxidizer to either absorb it or combust it to get it out of the air stream. This more traditional approach to treating TCE contamination in groundwater is often labor and capital-intensive.

The client didn’t want to build a pump-and-treat system at the facility. They wanted us to look at an in-situ approach—something that was below-grade that they didn’t have to spend a lot for O&M costs. And that’s when we started looking at chemical oxidation or other passive barrier technologies like zero-valent iron or biologically enhanced approaches.

Q:  How did you choose a biobarrier then?
A:  We had been doing research at a site in Michigan in 2001, the Bachman Road Research Project, where the research team we were part of isolated bacteria that could completely convert the TCE to ethene.

The Connersville client was very excited about the possibility of an in-situ treatment similar to what we had done in Michigan. So we did a bench test with Georgia Tech that proved promising, and then we did a pilot test at the site.

The Connersville site was a former automobile parts manufacturing facility. Before the parts were painted, our client cleaned them to remove the cutting oil using degreasers including TCE. We’re not exactly sure how the TCE release occurred, but a pathway allowed for the contaminant to get into the soil and into the groundwater beneath it.

To conduct the pilot test, we identified a portion of the groundwater plume that exhibited the highest concentration known at that time and tried the technology there. When that proved successful, we went full-scale and installed the first biobarrier along the property boundary on the downgradient side of the source area, like a cutoff wall to prevent any more contamination from leaving the property.

Q:  How is a biobarrier built?
A:  We install injection wells to place food and substrate—something for the bacteria to eat and also to change the environment from somewhat aerobic to very anaerobic. We do this because the bacteria Dehalococcoides only lives in anaerobic environments. This bacteria is the genus that has been identified as capable of converting chlorinated solvents, particularly PCE and TCE, and to ethene.

We inject substrate and food (which is just vegetable oil and sodium lactate) for the bacteria into the aquifer. The bacteria actually respires the PCE and TCE and gets energy by stripping the chlorine off the compound. So they eat the food and substrate, they breathe the TCE and PCE, and they get energy from doing the work we need them to do.

Q:  What is the role of groundwater modeling in this type of project?
A:  We use modeling to collect data to assess the characteristics of the local geologic formation, and then determine how large the barrier or treatment area will have to be. You can also determine if the groundwater that would normally flow through an area could be slowed down by the biobarrier. We do simulations with these scenarios ahead of the game to get the right design. We also use modeling to decide how long the biobarrier will need to be maintained.

Q:  So what do the regulators think about this solution?
A:  When the land changed ownership from the existing client to the City of Connersville last year, the regulators liked our approach to this technology and our methods so much that they gave brownfields loan money to the City to keep the project going. So we have the full support of the client and the regulators.

Q: Why do you think Tetra Tech has been so successful at it?
A:  Well I think part if it is that we were involved with the research project in Michigan. Being involved with the academic community in the mid- to late-90s, we were able to leverage that experience and apply what we learned there to this site.

It’s a collaborative effort with our client – from the beginning we were vested in this project because we knew it was sort of new and cutting edge. We’ve kept everybody informed and I think that sort of team approach has helped build a lot of positive energy between the various parties including the regulators, the client, and now the City.