Indirect bioremediation: biodegradation of hydrocarbons on a commercial sorbent

Abstract

Urea-formaldehyde polymer is currently used as asorbent for containment and clean up of hydrocarbons. The aerobic biodegradability of this polymer andhydrocarbons sorbed to the polymer were tested. Soilmicroorganisms readily grew on the polymer, and twoorganisms, a bacterium and a fungus, capable of growthon the polymer were isolated. However, biodegradationof the polymer was very slow and possibly incomplete. Biodegradation of the polymer was evident as a changein appearance of the polymer, but disappearance of thepolymer was not detectable in liquid culturesincubated for six months or soil cultures incubatedfor one month. Destruction of the polymer by soilmicroorganisms at ambient temperature does not appearto be practical. Degradation of ¹⁴C-labeledhexadecane and phenanthrene mixed with crude oil inliquid cultures inoculated with soil microorganismswas used as an estimate of general hydrocarbondegradation. When nitrogen was not limiting, therates of hexadecane and phenanthrene degradation werethe same, whether those hydrocarbons were sorbed tothe polymer or not sorbed. When nitrogen waslimiting, the polymer stimulated the rate ofhexadecane degradation but not the rate ofphenanthrene degradation. The polymer may stimulatehexadecane degradation by serving as a source ofnitrogen. However, optimal degradation of sorbedhydrocarbons requires nitrogen addition. The resultssuggest that it may be feasible to decontaminate spentpolymer by biodegradation of sorbed hydrocarbons.