Innovative Remediation Methods
Duncklee & Dunham believes the use of innovative assessment technologies that generate large data sets is a key to achieving cost-effective groundwater-remediation objectives. Large data sets are valuable in overcoming site complexity or heterogeneity. Supplementing site data collected with traditional methods allows for better mapping of the contaminant plume and soil matrixes, which is essential for the use of targeted remediation methods such as in-situ chemical oxidation. The data allows for better targeting of injection patterns into areas where the plume actually is present rather than the wasteful use of geometric injection patterns that could miss, to a significant extent, the actual location of the contaminant plume.
Duncklee & Dunham utilizes innovative methods such as membrane interface probe (MIP) techniques, laser-induced fluorescence (LIF), hydraulic profiling testing (HPT), field test kits, and mobile-laboratory services to map soil or groundwater plumes more quickly and accurately. Most of these methods provide real-time and high density data that allows our personnel to adjust and optimize the site-sampling plan while in the field. Duncklee & Dunham has also developed Corrective Action Plans that use underground injection of chemicals to oxidize Volatile Organic Compounds (VOCs) or carbon sources that enhance the biological breakdown of the VOCs. Chemicals such as steam or base-catalyzed sodium persulfate, hydrogen peroxide, Fenton’s Reagent, potassium and sodium permanganate, and slow-release oxygen compounds are used to oxidize and/or biodegrade organic compounds. The biological process of anaerobic reductive dechlorination can be enhanced by the addition of carbon sources such as lactate or emulsified vegetable oils.
MIP methods allow us to map contaminant plumes in real time with much greater accuracy, including the location of zones of dense non-aqueous phase liquids (DNAPL). MIP methods produce data that enable more accurate placement of monitoring wells to delineate both the horizontal and vertical extent of the groundwater plumes. Just as important on many projects, MIP methods show the best zones to target for the placement of in-situ chemical oxidants. For these sites, MIP methods provide real-time data in three dimensions that allows for quicker and more cost-effective remediation. The MIP data enables the delivery of remediation chemicals to specific contaminated zones, which generates a more effective cleanup and reduces the likelihood of aquifer recontamination (“rebound”) due to desorption of contaminants from zones that would have been missed by more conventional and less precise methods.
Mr. Dunham completed the remediation of a methyl tertiary butyl ether (MTBE) and other oxygenates groundwater plume in Delaware by performing targeted injection of steam-catalyzed persulfate. Mr. Dunham has designed and permitted an injection program that includes Fenton’s Reagent and biological augmentation at a major petroleum bulk plant on the Ohio River in Kentucky.
An example of our expertise with in-situ chemical oxidation is the closure by NCDENR of the regulatory file for a petroleum site after we applied base-catalyzed persulfate for a site in Raleigh, North Carolina. We believe this is one of very few sites closed by NCDENR thus far by the use of this technology. Duncklee & Dunham is successfully remediating groundwater plumes using dissolved solution or slurries of sodium permanganate, peroxide, steam-catalyzed persulfate, ORC®, and Regenox® products.