This established an attached spherical biofilter about 1 m in radius, though media heterogeneities result in significant departure from a spherical shape. Wells NW and SE, located about 80 cm away, enabled monitoring of the injection process. Groundwater samples were taken at all three wells to monitor TCE concentrations. Extraction and monitoring will occur atthis rate until the biofilter's TCE-degrading capacity is exceeded. We estimate this will occur afterabout one month.
Baseline values are from samples collected prior to cell injection.
A quasi-spherical attached biofilter about 1 m in radius was formed. Results conclusively show virtually complete biodegradation of the ppb TCE stream, from 425 ppb to less than 10 ppb. These results are compelling proof that an in situ biofilter was established and that virtually complete biodegradation of TCE occurred for the first 60h of the test. Biofilter performance gradually decreased for the remaining 37 days of the test until background TCE concentrations were recovered in the main well.