Low temperature oxidation for the remediation of soil contaminated with motor oil

Petroleum hydrocarbons (PHCs) react with oxygen by low temperature oxidation (LTO) to produce a coke-like solid residue, carbon oxide gases, and vaporized hydrocarbons. The feasibility of using LTO to remediate sandy soil contaminated with motor oil has been investigated in a plug flow reactor operated at temperatures between 150 and 221 degreesC and with air injection fluxes ranging from 0.40 to 2.28 m((ST))(3.)m(-2.)h(-1). Low temperature oxidation occurred in three successive periods: the induction period during which the oxygen depletion in the reactor exit stream remained small, the middle period characterized by peaks in oxygen depletion and carbon oxide concentrations, and the tailing period corresponding to very gradual decreases in oxygen depletion and carbon oxide concentrations. The extents of oxidation measured in our tests ranged from 29 to 37 moles O-2/kg oil. Soil samples treated at temperatures between 167 and 176 degreesC met all the Tier 1 levels of the Canada Wide Standard for PHCs in coarse-grained surface soils, except those for soil contact and protection of ground water. Concentrations of individual polycyclic aromatic hydrocarbons (PAHs) in the soil samples treated at 167 and 176 degreesC complied with the Canadian Environmental Quality Guidelines for all soil types.