Bioremediation was selected as either the initial treatment or final polishing step for five dry cleaner sites in the Seattle area and has already been applied at three of the sites. PCE concentrations range from very low (100's of ug/l) to DNAPL levels (160,000 ug/l). Daughter products are present at all five sites. Three of the sites are now empty lots but all still involve implementation under roads, parking lots and/or buildings. When dual phase extraction ends at the high concentration site (3rd photo); bioremediation will be evaluated as a polishing step.
One bio implementation used both bioaugmentation and the injection of micro scale zero-valent-iron (ZVI) to both treat PCE and help generate and maintain anaerobic conditions in the source zone for the microbes. Simply lowering a magnet into monitoring wells was sufficient to confirm the micro scale ZVI distribution (see black particles in 2nd photo).
