The potential of using composting technology to remediate clayey soils with high levels of crude oil contamination was evaluated. An open air windrow comprised of flare pit soil, manure and wood chips was constructed at Olds College, Composting Technology Centre. Aeration and mixing were carried out by a skid steer loader and composting parameters were monitored for ten months. Temperature profile of this windrow gave cyclic patterns of high and low temperature recordings corresponded to the turning events. Most of the microbial metabolic activity occurred within the mesophilic temperature range and the hydrocarbon degrading microorganism populations remained high throughout the trial. Complete removal of BTEX compounds was achieved within six months and extractable carbons from C-5 to C-10 were reduced by 98.7% compared to the initial contaminated soil. Vegetative growth on the composted soil was also evaluated. Barley and timothy plants grown in the composted soil were compared to the control off-lease soil, contaminated soil, and other treatments of varying salinity and organic matter levels. Plant germination, survival, and biomass production was significantly better in the composted soil than in the contaminated soil. Furthermore, barley plants grown in the composted soil were more resilient than those grown in the control off-lease soil.
