VPE 511: Environment and Environmental Hygiene (2+1)

PETROLEUM INDUSTRY

• Most of this waste is disposed of in hazardous landfills, which results in a high costs to the producers, without relieving them of the liabilities associated with these wastes. Some wastes are treated by thermal methods, especially in cement kilns or thermal desorbers.
• Conventional land farming bioremediation processes for the treatment of these wastes are not environmentally acceptable. By optimizing fermentation process parameters and by paying particular attention to strategies for increasing hydrocarbon accession to the petroleum degrading mixed culture, a cost effective bioreactor-based process with a relatively short cycle-time has been developed.
• Process constancy has been proven over hundreds of full scale runs by the conversion of hazardous into non hazardous waste. Supporting studies have illustrated the contrasting physiological mechanism exhibited by different component organisms in the mixed culture, particularly with respect to their association with the hydrocarbon substrate.
• In addition, the beneficial effects of using surfactants to improve hydrocarbon accession and the effects of key surfactant properties on degradation have been shown. From a different perspective, the process for the degradation of refinery oil wastes could be viewed as a low cost (or negative cost) fermentation process for the production of biomass, capable of transforming other hydrophobic molecules.
• Environmental requirements provide scope of microbiologist to optimize culture dependent and independent techniques in which oily soil slurry and sludge may be treated, with volatile organic carbon containment, and where rates and extent of hydrocarbon degradation are maximized.
• Petroleum biodegradation research is advancing on many fronts i.e. anaerobic hydrocarbon degradation (lagging behind aerobic systems), hydrocarbon accession to microbes (role of biosurfactants and their production), microbial consortia approach for degradation, microbial de-emulsification, desulphurization and denitrogenation of crude oil.
• Bacteria with selected petroleum metabolishing enzymes, amenable to being linked to electronic interfaces, are being engineered and developed as biosensors. These systems have applications in monitoring environmental contaminant concentration and toxicities during implementation of remedial process and also have potential applications to control environmental processes.