Remediation of btex contaminated areas: A microbial approach

Abstract

The hydrocarbon contamination resulting from petrochemical industries is regarded as a major environmental problem. Environmental impacts from such contaminants are particularly worrying, as continuous and prolonged pollution causes a high environmental persistence. Among the aromatic hydrocarbons, the BTEX mixture (benzene, toluene, ethylbenzene and xylene), which is abundant in petrol and diesel oil, deserves special attention because of its high toxicity and high volatility. Their elevated water solubility also leads to increased dissemination in surface waters, groundwater and the soil. Among the promising bioremediation rises as a very effective technique, due to its simplicity and low costs. They can also be potentially applied as a supplemental technique to conventional methods. The biodegradation of BTEX hydrocarbons depends on the activity of aerobic and anaerobic microorganisms capable of metabolizing them. Microbial effectiveness can be reduced, however, because hydrophobic compounds are immiscible in aqueous solutions and are adsorbed by sediment particles, limiting their bioavailability to the microbiota. The use of biosurfactants may therefore be a potential tool to improve the access of these molecules to the microbial metabolism. Some of these biological detergents are produced by Pseudomonas aeruginosa strains. Due to their surface-active properties, biosurfactants promote the increase of interfacial interaction of water/oil systems in the desorption of organic compounds into the soil matrix, hence accelerating biodegradation of hydrocarbons. As such, this chapter introduces ecologically feasible ways of treating environments contaminated by BTEX based on efficient microbial metabolism.