Feasibility of in situ NAPL-contaminated aquifer bioremediation by biodegradable nutrient-surfactant mix.

Entrapped non-aqueous liquid phase (NAPL) pollutants (e.g., fuels) constitute one of the biggest current problems in the bioremediation efforts of contaminated soil and aquifers worldwide. On site, in situ surfactant-enhanced bioremediation, in the presence of sufficient nutrients and dissolved oxygen, has the potential of becoming the remediation method of choice in terms of both technological and economical feasibility. This approach was applied in our lab-scale column-based flow system with the aid of which an optimized, below CMC, of biodegradable surfactant-nutrient surfactant mix has been established for the best solubilization/ mobilization of NAPL (hexane, toluene, kerosene and their mixtures as "representatives") in sandy matrix. For kerosene, the highest f values (the enhancement factors) were obtained for the systems containing either the amphoteric cocoamphodiacetate or the anionic linear dodecylbenzene sulfonate (0.1-0.3 g/L) with one or both the nutrient-surfactants L and B (0.05 g/L).