Degradation of weathered diesel fuel by microorganisms from a contaminated aquifer in aerobic and anaerobic microcosms
- Swiss Federal Inst. of Tech., Schlieren (Switzerland). Inst. of Terrestrial Ecology
A diesel fuel-contaminated aquifer in Menziken, Canton of Aargau, Switzerland, was in situ bioremediated from 1989 to 1994 by adding O{sub 2}, NO{sub 3}{sup {minus}}, PO{sub 4}{sup 3{minus}}, and NH{sub 4}{sup +} through an infiltration well. After a remediation time of 3.5 years, aquifer material from the contaminated zone was excavated and found to contain > 10{sup 6} hydrocarbon-degrading microorganisms/g and 1.15 {+-} 0.15 mg/g weathered diesel fuel comprising mainly isoprenoid alkanes and an unresolved complex mixture (UCM) of unknown components. Samples of this material were incubated for up to 470 days in aerobic and anaerobic microcosms. The microbial activity was determined by measuring the production of inorganic carbon and the consumption of O{sub 2} and NO{sub 3}{sup {minus}}. The degradation of the weathered diesel fuel was quantified by infrared spectroscopy and by capillary gas chromatography. In aerobic microcosms, all isoprenoid alkanes and most of the UCM were biodegraded as long as a nitrogen source was present. The O{sub 2} consumption could be stimulated by adding KH{sub 2}PO{sub 4} and by elevating the temperature to 22 C. In anaerobic microcosms with KNO{sub 3}, NO{sub 3}{sup {minus}} was consumed, inorganic carbon was produced, and the isoprenoid alkanes and the UCM were partially metabolized. In some selected microcosms, the NO{sub 3}{sup {minus}} consumption rate was stimulated by adding external substrates such as toluene, o-xylene, m-xylene, p-xylene, n-alkanes, or fatty acids. Mineralization of toluene, naphthalene, and hexadecane to CO{sub 2} under denitrifying conditions was confirmed by using [{sup 14}C]-labelled substrates.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 215602
- Journal Information:
- Environmental Toxicology and Chemistry, Vol. 15, Issue 3; Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
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