Evaluation of matrices for the sorption and biodegradation of phenanthrene

Abstract

Permeable reactive barriers (PRBs), a new cost effective technology for the remediation of contaminated groundwater, have rarely been considered for PAH contamination. We evaluated three candidate matrices (activated carbon (AC), pouzzolana coated (PzF) or not (Pz) with heavy fuel oil) for phenanthrene (PHE) sorption capacity and the biodegradation of adsorbed PHE. Adsorption–desorption batch experiments showed higher sorption capacity of AC than PzF (60 fold) and Pz (1500 fold). Sorption isotherms were not linear for all matrices as described by a Freundlich model. Phenanthrene desorption from AC and PzF within 48 h was limited (1–3%). Mineralization of 14C-PHE by a PAH-degrading bacterial strain increased in the presence of AC and Pz (+16 and +12%). Among the three matrices, AC may be a good candidate for PRBs due to high adsorption, low desorption and increased PHE degradation.