Fate, Transport, and Bioremediation of Biodiesel and Blended Biodiesel in Subsurface Environment: A Review

As biofuels and blended biofuels are being globally used and expected to increase in the near future, their fate and transport in the soil-water system is an area of major concern. The biological origin and differences in physical-chemical characteristics of biodiesels from petro-diesels may alter its fate and transport behaviors in the subsurface. Introduction of biodiesel liquids into a partially saturated zone can modify the air-water system as a multiphase (i.e., biodiesel-air-water) system which controls its distribution in the subsurface. Competitive adsorption and high volatilization of lighter compounds from blended biodiesels can also alter the movement of the free phase. Similarly, the rapid-dissolving nature of biodiesels in pore water provides sufficient carbon sources to subsurface microbial communities which significantly enhance microbial cometabolisms and therefore biodegradation rate under an aerobic condition. This manuscript presents the review updates and current understanding of fate, transport, and bioremediation of biodiesel and blended biodiesel in the subsurface. The insights discussed in this manuscript may help groundwater scientists, environmentalists, and geochemists in predicting the behavior of biodiesel and blended biodiesel contaminants in a different landscape and in assessing risks of contaminations.