Biodegradation of petroleum wastes in soil: The microbial ecosystem and optimization of a treatment process
Treatment of hazardous waste can be accomplished by incorporation into the upper soil horizon. Indigenous complex communities of soil microorganisms enzymatically adapt to and degrade the added substrate. Waste streams from the petroleum industry are particularly suitable for land treatment, as many of the constituents are readily degradable. An intensively-used petroleum waste land treatment system was studied over a three-year period. Monitoring methods, including laboratory media, were developed or adapted for studying petroleum-degrading microorganisms. Activity was assessed as carbon dioxide evolution from the treatment soils. Residual waste concentrations and soil moisture content were measured over time. Microenvironments and soil aggregates were investigated for niche diversity, respiratory activity and effects of waterlogging. Biodegradation of petroleum waste in the treatment soils varies substantially in time and space. Degradation rates are maximized with moderate, frequent waste loadings, providing the stable microbial community with continuous usable substrate. Progressive development of large soil aggregates promotes the formation of anaerobic conditions, slowing degradation rates and shifting the microbial population structure. An aggressive program of tilling controls the formation of aggregates, enhances waste-to-microorganism contact and provides oxygen to diffusion-limited microenvironments. The optimal soil water content for this system is 14 to 15% by weight. Correct moisture levels are undoubtedly site-specific. Lower levels inhibit cellular processes while higher levels limit gaseous diffusion.
- Research Organization:
- University of Southern California, Los Angeles, CA (USA)
- OSTI ID:
- 7025644
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020800* -- Petroleum-- Waste Management
BACTERIA
BIODEGRADATION
BIOSYNTHESIS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CULTIVATION TECHNIQUES
DECOMPOSITION
GROUND DISPOSAL
HAZARDOUS MATERIALS
INDUSTRIAL WASTES
INDUSTRY
MANAGEMENT
MATERIALS
MICROORGANISMS
MOISTURE
MONITORING
OXIDES
OXYGEN COMPOUNDS
PETROLEUM INDUSTRY
POPULATION DYNAMICS
PROCESSING
SATURATION
SOILS
SYNTHESIS
WASTE DISPOSAL
WASTE MANAGEMENT
WASTE PROCESSING
WASTES
WATER SATURATION