PARENT SESSION

1B+C Abiotic Transformation + Biodegradation
Hall 9
1:45 PM - 3:30 PM, Monday, 28 April 2003
Chair: Peijnenburg, W.¹, ¹
Co-chair: Jafvert, C.T.², Gombar, V.K.³, ^{2 3}

(MO9/14) The Degradation of Polycyclic Aromatic Hydrocarbons in Sediments by a Chemical-Biological Process Employing Peroxy Acids.

Nyman, Marianne¹, N'Guessan, Lucie¹, Levitt, Jeffrey¹, Dutkus, Kerry¹, Carignan, Todd¹, ¹ Rensselaer Polytechnic Institute, Troy, New York, USA

ABSTRACT- The ubiquitous presence of polycyclic aromatic hydrocarbons (PAHs) in our environment is a concern due to their toxicity and carcinogenecity. A new and innovative hybrid method employing a chemical process followed by a biological process is being developed as an efficient and cost effective technique for degrading these persistent compounds found both in soil and sediment. The chemical process involved the use of hydrogen peroxide and acetic acid to generate reactive hydroxy radicals, which in turn oxidize the very stable PAHs compounds. Sediment collected from Suffield (CT, USA), Newington (CT, USA), and Southwick (MA, USA) varied in organic carbon (OC) content and particle size distribution. The OC content ranged from 0.3 % to 1.4 % and the sediment samples were characterized predominantly as silty-clay, sandy-clay and sandy. Laboratory experiments have been conducted to study the transformation and degradation of two representative PAHs (e.g., -methylnaphthalene and benzo(a)pyrene) spiked into the three different sediment types using a peroxyacetic acid treatment. Transformation was observed to be more complete for -methylnaphthalene than for benzo(a)pyrene over a period of 24 hours. Organic carbon content and sediment surface area were found to play an important role in the availability and transformation efficiency of the PAHs investigated. The subsequent degradation of the parent compounds and their chemical treatment byproducts by a culture of microbes seemed feasible but not without limitations due to the high concentration of acetic acid from the chemical process. This hybrid process was also tested on "real" contaminated soil. The results obtained in this case proved promising.

Key words: peroxy acid, pah, biodegradation, aop