Biodegradation of petroleum-based oil wastes through composting

Composting of horse manure was used as a means of degradation of two oil wastes, oil sludge from petrol stations and petroleum residues from a refinery. Paraffin oil was chosen as a reference. Oil wastes decomposed to 78-93% during 4.5 months of composting. The degradation of the waste oils was higher than that of the reference paraffin oil and no difference was found between the two types of oil wastes concerning their decomposition. At the end of the experiment, most of the polyaromatic hydrocarbons had been degraded except pyrene, chrysene and dibenz(ah)anthracene. Gaseous losses of oil compounds through volatilisation from composts were found not to be significant.