ABSTRACT
As landfills have become more and more scarce and cost prohibitive, interest in biological methods to treat organic wastes, and in particular petroleum contamination, has increased and received more attention. Crude oil is an extremely complex and variable mixture of organic compounds which consist mainly of hydrocarbons in addition to heterocyclic compounds that contain sulphur, nitrogen and oxygen, and some heavy metals. The physical state of petroleum hydrocarbons has a marked effect on their biodegradation. Crude oil in aquatic systems, usually does not mix with seawater, and therefore, floats on the surface, allowing the volatilization of the 12 carbons or less components. In most petroleum-contaminated soils, sediments, and water, oxygen usually is the limiting requirement for hydrocarbon biodegradation because the bioremediation methods for reclamation of these contaminated sites is mainly based on aerobic processes.
