BIOREMEDIATION ENHANCEMENT OF PHENANTHRENE CONTAMINATED SOILS BY CHEMICAL PREOXIDATION

A two-step oxidation process was investigated for the treatment of phe nanthrene contaminated soil fines (particle diameter <63 mu m) resulti ng from a soil washing process. Oxone(R) (2KHSO(5) . KHSO4 . K2SO(4)) and hydrogen peroxide (H2O2) were used as oxidants fbr the chemical pr e-oxidation step and unacclimatized municipal activated sludge was emp loyed in the subsequent biodegradation step. Oxone was found to have a n oxidation efficiency approximately ten-fold greater than hydrogen pe roxide on a stoichiometric basis. In comparison to chemical oxidation only, a 24 hour pre-oxidation step using 5 and 10 g/L Oxone followed b y a 5 day biological oxidation step enhanced the removal of phenanthre ne from the soil by 115% and 32%, respectively. Similarly, a 48 hour p re-oxidation step utilizing 5 and 10 gn Oxone followed by a 5 day biol ogical oxidation step enhanced the removal of phenanthrene from the so il by 113% and 43%, respectively. Based on this preliminary assessment , a treatment protocol that integrates a 24 hour chemical preoxidation step with 5 g/L Oxone followed by a 5 day biological oxidation step a ppears to be an effective combination for the remediation of this phen anthrene contaminated soil.