Environmental Projects

Successful Bioremediation of a Dilute 44-Acre Plume
(South Bend Indiana)

INNOVATIVE ENGINEERING SOLUTIONS, INC. has been conducting a large scale (19 acre) enhanced anaerobic dechlorination (EAD) pilot test since May 2006. The highly successful (99% decline in VOC concentrations and conversion to ethene) bioremediation of the (initial) 19 acres has lead the way to the design and installation (in 2009) of a final remedy to cover the entire 44-acre dilute VOC plume. The EAD pilot test used a groundwater recirculation system that includes 6 extraction wells and thirteen injection wells spanning an area that is approximately 300 feet wide. Groundwater (contaminated with 2 to 3 ppm of TCE and its breakdown products) is recirculated within this area at an approximate flow rate of 30 gallons per minute within the sandy aquifer. The amendment dose is approximately 15,000 pounds/month of total organic carbon (TOC) using a whey solution stabilized with molasses (molwhey). Molwhey is the lowest cost electron donor that is available and is an ideal substrate lasting up to one year in the aquifer. Coupled with the site's high groundwater velocity (1,500 feet per year), our enhancement system has fed 19 acres in roughly 1.5 years. Bioaugmentation was conducted using our NJ-14 culture and there is evidence that it has migrated to distances exceeding 700 feet.

The final remedy (RCRA corrective action site-fully installed in 2009 per the CMS) included a second bioremediation zone and expansion of the initial installation for eventual remediation of approximately 44 acres. There is evidence that at the downgradient plume fringe co-metabolic degradation is also taking place (methane as a co-metabolite).

To the best of our knowledge this project represents the first demonstrated full scale EAD application of such a large plume. Our work has received praise from the USEPA in how this project demonstrates the feasibility of large plume remediation.