Bioremediation of Petroleum Sludge

Bioremediation, or the use of micro-organisms to decontaminate soil or groundwater, is being increasingly seen as an effective, environmentfriendly treatment for oilcontaminated sites. Many reports indicated that, large quantities of organic and inorganic compounds are released into the environments every year as results of human activities causing serious environmental problems. Among those problems are oil contamination of soil and water from industrial sources and other activity, which create a great environmental hazard [1]. Petroleum hydrocarbon continues to be used as principle source of energy and hence a large global environmental pollutant. Petroleum is a complex mixture of non-aqueous and hydrophobic components. Many of these components are toxic, mutagenic and carcinogenic [2]. Therefore, the release to the environment is strictly controlled and they classified as priority environmental pollutant by US Environmental Protection Agency, due to their adverse impaction human health and environment [3]. Various physiochemical treatments techniques have been developed to clean up contaminated soil such as incineration, thermal desorption, chemical oxidation, immobilization and solvent extraction [4]. In general such treatments are more expensive, energy intensive and not sustainable with respect to their environmental impact which includes damage to the soil structure and toxicity issue associated with chemical additives [5]. Many of these techniques simply dilute or sequester the contaminants and do not eliminate the problem [6]. In general such treatments are more expensive, energy intensive and not sustainable with respect to their environmental impact which includes damage to the soil structure and toxicity issue associated with chemical additives. Traditionally, petroleum hydrocarbon contaminated soils have been dealt with by excavation and disposal to landfill. However, as landfills have become scarcer and more cost prohibition, this method has become less feasible [7]. These limitations have been the basis of search for more economical and environmentally sound approaches to remediate contaminated soil. Biological treatment of organic pollutants is a promising field of research, which gives reliable, simple and cheap technologies over chemical and physical process [8]. Bioremediation has become a major method employed in the restoration of oil polluted environments, and attempts to accelerate the natural hydrocarbon degradation rates by overcoming factors that limit bacterial hydrocarbon degradation activities [8,9]. Microorganisms, namely heterotrophic bacteria and fungi have evolved a tremendous ability to metabolize simple and complex hydrocarbon contaminants [10]. By harnessing their metabolic ability, it is possible to remediate contaminated environments, a technique referred to as bioremediation [11].