Biosurfactant-enhanced removal of petroleum hydrocarbons in a soil bioremediation system

This study aims at the characterization of an advanced biosurfactant- enhanced soil bioremediation system within a context of Canada, where the low atmospheric temperature in the winter season leads to low viability of microbial activities. Samples with aged naphtha contaminants were collected from boreholes of a Canadian site, the Coleville site, and loaded into an experimental cell. Both the vadose zone and the saturated zone conditions were simulated in the cell under a low temperature (10°C). Two sources of biosurfactant solutions were applied. One came from the bulk production in lab by the biosurfactant-producing bacteria isolated from the Coleville site, and another one (rhamnolipid RECO-10, 10% solution) was purchased from Jeneil Biosurfactant Co. (WI, USA). Effects of two sources of biosurfactants with different concentrations on hydrocarbon removal rate in both vadose and saturated zones were investigated. Analytical results showed that biosurfactant concentration had the most significant effect (Bi = 49.4) on benzene (the target contaminant) removal compared with those of soil zone (Bi = 10.7) and biosurfactant source (Bi = 3.57). Moreover, the lab-produced crude biosurfactant solution showed a higher capacity to enhance bioremediation than the purchased one. The research outputs made it possible to better control the experimental system and refine the remediation techniques, and indicated the strong potential of biosurfactants to improve efficiencies of site remediation in Canada.