Mass reduction by DPE and SVE at a hydrocarbon- and MTBE-impacted site had become uneconomical.
Site managers asked: “Can we transition to MNA?” The answer, for the most part, was yes. Post SVE, hydrocarbon and MTBE concentrations showed decreasing trends in most monitoring wells. Additional strong lines of evidence for in situ biodegradation of benzene and MTBE under MNA conditions were provided by QuantArray®-Petro analysis of catabolic functional genes and stable isotope probing (SIP) using 13C-benzene and 13C-MTBE. One area of weak activity was also identified necessitating enhanced biodegradation in that zone.
QuantArray®-Petro and SIP analyses clearly supported an MNA management strategy across most of the site. Although a zone with lesser biodegradation activity was identified this observation allowed enhanced biodegradation at the site to be targeted saving money and supporting earlier site closure.
