Bioremediation technologies for treatment of PAH-contaminated soil and strategies to enhance process efficiency

The complex and diverse structural configurations of polycyclic aromatic hydrocarbons (PAHs), combined with their low bioavailability, hydrophobic nature, strong sorption phenomena, and high persistence in soil makes the design of effective bioremediation methodologies a challenge. The multi-phasic nature of the bioremediation process, restricted mass transfer and non-availability of degrading soil microflora further compound the problem. In this direction, this communication presents a focused review of bioremediation technologies used recently for the treatment of PAH-contaminated soils. The specific roles of important factors affecting bioremediation process efficiency are discussed. Finally some of the recently used strategies to enhance bioremediation process efficiency, including bioaugmentation, biostimulation, rhizoremediation, the use of chemotaxins, the biomimetic catalytic system approach, and integrated techniques, are reviewed.