Remediation of hydrocarbon contaminated soils in the Canadian Arctic by landfarming: Fid-Bau Portal

Remediation of hydrocarbon contaminated soils in the Canadian Arctic by landfarming

Paudyn, Krysta / Rutter, Allison / Kerry Rowe, R. / Poland, John S.

AbstractOne of the preferred methods for the remediation of fuel contaminated soil today is landfarming. This is particularly true for remote sites because the method requires minimal equipment and is therefore by far the lowest cost option. The term landfarming generally refers to the process whereby hydrocarbon contaminated soils are spread out in a layer about half a meter thick, nutrients are added, and periodically the soils may be mixed. During landfarming, hydrocarbons can be lost through volatilization or bioremediation and thus landfarming refers to the combination of the two processes.In the challenging Arctic climate, the performance of landfarming studies has been variable and the relative contribution of the two processes has not been studied. This paper describes the successful remediation of diesel-contaminated soils at the former military base at Resolution Island, Nunavut. The site is 130 km from the nearest community and this isolation together with very inclement weather and average summer temperatures of 3 °C presents significant challenges for remediation. Trial landfarm plots were established in 2003 to compare four sets of conditions; daily aeration, aeration every 4 days, addition of fertilizer with aeration every 4 days and a control plot. The field trial has clearly demonstrated enhanced bioremediation when fertilizer was added and also significant hydrocarbon losses due to aeration by rototilling. The rate of bioremediation was similar to the rate of volatilization in the field trial. In addition to the landfarms established on site, extensive complementary laboratory experiments have been carried out. Bioremediation was demonstrated at 5 °C in the laboratory reactors and isoprenoid markers indicated increased bioremediation with increased temperatures. In the reactor experiments, rate constants for volatilization and bioremediation increased with temperature.