Aerobic slurry reactor treatment of phenanthrene contaminated sediment

Studies were conducted to evaluate the bioremediation of 14C-phenanthrene contaminated sediments under simulated in-place slurry reactor conditions. This included experiments investigating the rate of oxygen demand exerted by the sediments, the rate and extent of phenanthrene release under slurry conditions, and the fate of phenanthrene in an aerated slurry bioreactor. Experiments were conducted with estuarine sediments collected from Dickinson Bayou (near Houston, Texas, U.S.A.). Procedures were employed to minimize exposure of sediments to oxygen during handling and aging with 14C-phenanthrene. The sediment oxygen demand (SOD) was determined to be 250 mg/kg O2—principally due to the presence of acid volatile sulfides. Under slurry conditions, rapid partitioning of phenanthrene was observed. In mixed bioreactors operated for 7 days, complete phenanthrene disappearance was observed, although volatilization losses were significant. Results of these studies provide useful information into the operation of slurry reactor systems and potential methods of enhancing system performance.