Oil-contaminated soil can be turned into a fertile soil using pyrolysis technique (heat to 350C without oxygen) in this article. This is very similar to the standard biochar technique except the feed stock is the oil-contamination. This is promising but the “other” harmful chemicals may be detrimental to human health. More studies are needed.
Intense heating has been used in the past as a means of rapid response to oil spills, but typically even higher heats are employed and oxygen is introduced to incinerate ALL the hydrocarbons, including those that lead to char. This method is much more energy intensive thanks to the higher temperatures required and leaves the soil completely depleted in regards to future plant growth. Conveniently, however, the new technique requires the same equipment and expertise as the older more energy-demanding strategy making it easy to deploy in the field. – See more at: http://inventorspot.com/articles/oil-contaminated-soil-finds-new-fertility#sthash.U1ihorD6.dpuf
Photo credit: Julia Vidonish/Rice University.