Biodegradation of NSO-compounds under different redox-conditions

S. Dyreborg, E. Arvin, K. Broholm

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    Laboratory experiments were carried out to investigate the potential of groundwater microorganisms to degrade selected heterocyclic aromatic compounds containing nitrogen, sulphur, or oxygen (NSO-compounds) under four redox-conditions over a period of 846 days. Eight compounds (pyrrole, 1-methylpyrrole, quinoline, indole, carbazole, dibenzothiophene, benzofuran, and dibenzofuran) were degraded under aerobic conditions, whereas thiophene and benzothiophene were degraded only when other compounds were degraded concomitantly. Quinoline and indole were the only two NSO-compounds degraded under anaerobic conditions, even though the microorganisms present in the anaerobic microcosms were active throughout the incubation period. A high variability in the lag period among the NSO-compounds was observed under aerobic conditions. While quinoline, indole, and carbazole were degraded with a lag period of 3-25 days, the lag periods for pyrrole, dibenzothiophene, benzofuran, and dibenzofuran were significantly longer (29-278 days). Under anaerobic conditions, lag periods of 100-300 days were observed. Differences in the degradation rate among the compounds were also observed. Indole, quinoline, carbazole, and benzofuran were quickly degraded in the aerobic microcosms, whereas a slow degradation of dibenzothiophene and dibenzofuran was observed. Pyrrole and 1-methylpyrrole were slowly degraded and 1-methylpyrrole was not completely removed within the 846 days. The anaerobic degradation rate was significantly slower than the aerobic degradation rate. The degradation rate under sulphate-reducing conditions was higher than under denitrifying and methanogenic conditions, though after re-addition of a compound a quick removal was observed.

    The persistence of many NSO-compounds under anaerobic conditions together with the long lag periods and the low degradation rates under aerobic conditions suggest that NSO-compounds might persist in groundwater at creosote-contaminated sites. (C) 1997 Elsevier Science B.V.
    Original languageEnglish
    JournalJournal of Contaminant Hydrology
    Volume25
    Issue number3-4
    Pages (from-to)177 - 197
    Number of pages21
    DOIs
    Publication statusPublished - Mar 1997

    Keywords

    • biodegradation
    • creosote
    • groundwater microorganisms
    • heterocyclic aromatic compounds
    • redox-conditions

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