Stimulated petroleum biodegradation.

Stimulated biodegradation has been considered as a method for removal of petroleum pollutants. Various methods have been proposed for increasing rates of petroleum biodegradation, including physical or chemical modification of petroleum polutants, modification of environmental parameters around polluting oil, and modification of microbial populations around petroleum pollutants. Physical or chemical means for stimulating petroleum biodegradation include removal of particular petroleum fractions by dissolution, burning, and emulsification. Modification of environmental parameters (such as concentrations of essential nutrients, especially nitrogen, phosphorus, and oxygen) has shown the greatest promise for stimulating petroleum biodegradation. Forced aeration and addition of commercial fertilizer combinations in contained systems, addition of fertilizer with tilling in soil, and addition of fertilizer that has been rendered oleophilic in open systems have all been shown to effectively stimulate petroleum biodegradation. Modification of microbial populations by seeding with oil-degrading microorganisms appears to be valuable in stimulating petroleum biodegradation only in limited situations where the naturally occuring numbers of hydrocarbon-degrading microorganisms are low.