Evaluating The Addition of Fine Particles To Enhance Oil Degradation

Abstract

ABSTRACT Natural biodegradation rates of oil within the marine environment are partly controlled by surface availability, as microbial attack primarily occurs at the oil-water interface. Therefore, increasing the surface area of residual oil by the addition of fine oleophilic particles may prove to be an effective bioremediation strategy. Considering commercial availability and cost, heat-treated peat was identified to be a promising particle source as it has high oil absorption properties and does not compete with oil as an alternative carbon source to oil-degrading bacteria. A preliminary laboratory experiment conducted with a respirometry system demonstrated the feasibility of nutrient and peat additions to enhance the metabolic activity of bacteria within oil-contaminated sand beach sediments. Field trials were conducted with similar peat and nutrient concentrations in a north-temperate beach environment with weathered Scotian Light crude oil over a 138-day period. The rates of microbial respiration and productivity were enhanced significantly above unoiled and oiled control sediments with the addition of inorganic nutrients with and without peat amendments. Treatment of sediments with inorganic nutrients and peat did not increase the toxicity of the residual oil. Gas chromatography/mass spectroscopy analysis was used to quantify bioremediation success by normalizing the loss of individual components to the conserved marker 17?(H), 21?H)-hopane. While there is evidence of a stimulatory effect with the addition of peat, results suggest that nutrient availability in the interstitial water limited optimal rates of oil bioremediation.