Potential for bioremediation of petroleum hydrocarbons in groundwater under cold climate conditions: A review

Globally, bioremediation is a common choice for remediation of petroleum hydrocarbon-contaminated sites. For application at cold climate sites, bioremediation approaches are appealing because they have potential to be more efficient and cost-effective than alternative, more energy intensive approaches. Several bioremediation approaches have been reported to be successful for petroleum hydrocarbon-contaminated soils at cold climate sites. In contrast, there are relatively few publications on applications of bioremediation for petroleum-contaminated groundwater at cold climate sites. Most of the existing relevant groundwater studies were conducted at sites with either no permafrost, or with sporadic to discontinuous permafrost. To date, the majority of cold climate groundwater investigations were at fuel spill sites; few studies on bioremediation of dissolved hydrocarbon plumes derived from crude oil or gas condensate have been published. Some studies reported that extents of hydrocarbon plumes in groundwater were limited by natural attenuation, including intrinsic bioremediation. At other sites, oxygenation of groundwater or amendments with nitrate were reported to be successful techniques for enhancing biodegradation of petroleum hydrocarbons. Both aerobic and anaerobic processes appear to be important at these sites. Based on three case studies, bioremediation (in situ or ex situ) may be feasible for sites with extensive permafrost. Further research and field demonstrations are required to establish or confirm the applicability of bioremediation technologies to clean up hydrocarbons in groundwater in various hydrogeological settings at cold climate sites.