Innovative Enhanced Reductive Dechlorination Design Cleans Up Large, Fast Moving Plume
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Narrator: Crawfordsville, Indiana, is a small city located in Montgomery County, Indiana, home to Wabash College, one of only three remaining all-male liberal arts colleges in the country. Historic Crawfordsville has a number of landmarks on the National Register of Historic Places, established in 1823 by Major Ambrose Whitlock. The city was named Crawfordsville in honor of Colonel William H. Crawford.
WSP, a leading global environmental firm, was chosen by the client to address a large plume standing from historic dry cleaning operations using chlorinated solvents known as tetrachloroethylene or PCE. The plume was fast moving at a rate of 1,000 feet annually and had spread throughout the small historic downtown area, and into a residential section of town.
Over the years, WSP had placed 65 wells throughout a 7-block area to monitor levels and determine an appropriate course of action. Since the plume ran below the municipal roads and a main busy highway, treating the plume had proved challenging over the years. Protecting a nearby residential neighborhood and local business added to the complexity of the site’s treatment. Teaming with Regenesis, WSP chose a combined approach using 3-D Microemulsion or 3DMe, BDI Plus, and CRS as an effective amendment solution to address the PCE levels present in the ground water and silty sand geology.
Adam: Regenesis is well-known nationally. And for this particular site, we looked at several different options, different companies, that provided similar-type products. And this is one that seemed to provide good value. There was minimal additional documentation that we had to provide in order to get the regulatory buy off on doing this particular type of remediation.
Ryan: Our work with WSP has been great. They’re very in tune with the site problems and challenges specifically related to access of the plume. 3-D Microemulsion is a very predictable product when applied correctly. So we’ll know exactly what to expect as we do performance monitoring.
Narrator: 3DMe is an injectable liquid material specifically designed for in-situ remediation projects, where the anaerobic biodegradation of chlorinated compounds through the enhanced reductive dechlorination or ERD process is possible.
ERD is the primary anaerobic biologic process by which problematic chlorinated solvents such as tetrachloroethylene, PCE, and trichloroethylene, TCE, dichloroethylene, DCE, and vinyl chloride, VC, in ground water are biologically transformed into less harmful end products such as ethene. 3DMe exhibits unique subsurface distribution characteristics which allow it to distribute widely within the subsurface. As a result, 3DMe can treat wide areas around an individual injection point, saving both time and money as it relates to the number of application points required. Unlike most ERD solutions, 3DMe provides three unique electron donor materials in a single product. The staged release of its three individual electron donor compounds results in immediate mid-range and long-term controlled release supply of organic acids to fuel the ERD process.
WSP site plan included direct push injection applications of 3DMe to treat the 1,800-foot-long plume that reached an area of 7 city blocks. The application events were designed to promote the degradation of chlorinated solvents in the designated treatment area through anaerobic bioremediation. The first injection event in 2013 incorporated three barriers using 3DMe and BDI Plus. The RRS team used direct push technology to inject the combined amendments into points to create the three barriers.
Scott: It’s been a great collaboration with Adam Heft at WSP. We design remediation strategies that fit his client’s budget, as well as the timeline that they need to achieve.
Narrator: The next scheduled event in 2014 included three additional barriers installed at three separate locations. Another planned application was scheduled in 2016. This injection application consisted of 6,000 pounds of 3DMe and 28 liters of BDI Plus also placed via direct push technology. Following the three applications of 3DMe and BDI Plus and subsequent monitoring events, WSP and Regenesis were pleased with the results and scheduled a final application for this site.
Adam: I like working with Regenesis quite a bit. Most probably the fact that were able to take the investigation right from the beginning, see it through the end and do it well, do it right, and do it as cost-effectively as possible for our clients.