Comparison of bioaugmentation and biostimulation in ex situ treatment of diesel contaminated soil

Abstract

A bioremediation programme was designed to investigate several factors that may influence the rate of diesel removal in an ex situ treatment of a contaminated soil. These were bioaugmentation; biostimulation via inorganic fertiliser (NPK) or manure as an organic source of nutrients; and bulking agents added to improve aeration within the systems. From a high initial level of diesel, removal/degradation proceeded rapidly in all but the non-amended control. In non-augmented systems, diesel removal in windrows proceeded significantly more rapidly than in biopiles. However, the most rapid remediation occurred in bioaugmented systems, where the inoculum consisted of laboratory enrichments of diesel-degrading microorganisms, with soil from the contaminated site as initial inoculum. All such systems reached the remediation end-point within one week, and no difference in rate due to windrows, static biopiles, or source of nutrients could be discerned.