OIL BIOREMEDIATION USING INSOLUBLE NITROGEN-SOURCE

Oil bioremediation is limited by the availability of nitrogen and phos phorous. which are needed by the bacteria and not present in sufficien t amounts in hydrocarbons. The supply of these two essential elements as water-soluble sails presents several problems. These include the ra pid dilution of the salts in the large volumes of polluted land or wat er and their utilization by other bacteria that do not degrade oil. In addition, increasing the concentration of mobile nitrogen creates fur ther environmental problems. The use of hydrophobic sources of nitroge n and phosphorous that have a low water solubility can overcome these problems. We have studied one such compound, F-1, that is not used by most bacteria but serves as a good nitrogen and phosphorous source for those bacterial strains that are capable of utilizing it. We have sho wn that bacteria using F-1 do not cross-feed other bacterial strains. Moreover, when the concentration of the pollutant is sufficiently redu ced, the multiplication of the bacteria slows down until they become a negligible fraction of the bacterial population. Chemical analysis in dicated that following a 28-day treatment of Alaskan crude oil, most o f the hydrocarbons, including polycyclic aromatics, are degraded to un detectable levels. The C-34 and C-35 components were also degraded, al though their degradation was not completed within this time period. In treatment of a sandy beach that was accidentally polluted with crude heavy oil, about 90% degradation was obtained within about 4 months at an outside average temperature of 5-10 degrees C. Copyright (C) 1996 Elsevier Science B.V.