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

Entrapped non-aqueous liquid phase (NAPL) pollutants (e.g., fuels) constitu te one of the biggest current problems in the bioremediation efforts of con taminated soil and aquifers worldwide. On site, in situ surfactant-enhanced bioremediation, in the presence of sufficient nutrients and dissolved oxyg en, has the potential of becoming the remediation method of choice in terms of both technological and economical feasibility. This approach was applie d in our lab-scale column-based flow system with the aid of which an optimi zed, below CMC, of biodegradable surfactant-nutrient surfactant mix has bee n established for the best solubilization/ mobilization of NAPL (hexane, to luene, kerosene and their mixtures as "representatives") in sandy matrix. F or kerosene, the highest f values (the enhancement factors) were obtained f or the systems containing either the amphoteric cocoamphodiacetate or the a nionic linear dodecylbenzene sulfonate (0.1-0.3 g/L) with one or both the n utrient-surfactants L and B (0.05 g/L).