The client’s consultant performed a pilot test that appeared to be successful and developed a work plan for full-scale enhanced bio for a TCE source area at a Superfund site. An Explanation of Significant Difference (ESD) to the ROD included enhanced bio as one alternative and a bio work plan was completed.
I provided a 3rd party review of the pilot results and full-scale work plan. The resulting tech memo showed the pilot results were not representative of a full-scale application, and enhanced bio would not meet the client’s goals of reducing concentrations sufficiently (due to the presence of DNAPL) prior to capping the site within a year. This prevented full-scale implementation at a cost-savings to the client in excess of $1,500,000. NOTE: This evaluation occurred in 1996 when it was believed DNAPL could not be treated with bioremediation. Our knowledge has changed in the past 15 years, however, this was still the correct decision given the client’s time schedule for the site.