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Behavior of chemical contaminants under controlled Redox conditions in an artificial sequential soil column system and in batch cultures

Nay, Michael ; Snozzi, Mario ; Zehnder, Alexander

In: Biodegradation, 1999, vol. 10, no. 6, p. 405-414

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    Title
    • Behavior of chemical contaminants under controlled Redox conditions in an artificial sequential soil column system and in batch cultures
    Author
    • Nay, Michael. Department of Microbiology, Swiss Federal Institute for Environmental Science and Technology (EAWAG), Überlandstraße 133, 8600, Dübendorf, Switzerland
    • Snozzi, Mario. Department of Microbiology, Swiss Federal Institute for Environmental Science and Technology (EAWAG), Überlandstraße 133, 8600, Dübendorf, Switzerland
    • Zehnder, Alexander. Department of Microbiology, Swiss Federal Institute for Environmental Science and Technology (EAWAG), Überlandstraße 133, 8600, Dübendorf, Switzerland
    Document Type
    • Postprint
    OAI-PMH Identifier
    • oai:doc.rero.ch:310962
    Summary
    A leachate pollution plume was simulated in a sequential soil columnsystem (SSCS), defined by a longitudinal redox cascade from methanogenic,sulfate-, nitrate-reducing to aerobic conditions. A mixture of contaminants,including compounds such as perchloroethene (PER), 1,1-dichloroethene(DCE), 1,4-dichlorobenzene (DCB), 2-nitrophenol (NP), and benzene (BEN)was supplied to the methanogenic column; their conversion was followed during passage through the SSCS. After establishment of a steady state, parameters were changed to simulate changes in the environment and to follow the reactions of the system. Acetate, initially introduced as an anaerobically easy degradable carbon source, was first omitted and later added again to the system. Furthermore, the medium flow rate and by that the load of the test compounds was increased 4 fold. Changes transiently increased the residual concentrations of most of the xenobiotics. Within seven months after acetate omission, turnover ofcontaminants had almost returned to the original steady state. Flow andload increase resulted in increased transformation of compounds such asPER, NP, and BEN. After readdition of acetate, the turnover of most ofthe xenobiotics increased within the next five weeks.Microbial populations for the anaerobic batch cultures, obtained from thespecific columns, were used to investigate metabolites formed and conversion kinetics of the xenobiotics. Almost the sameconversion pattern was found in batches and columns, except no transformation of DCE and DCB was detected in the SSCS, though both compounds were converted in batch cultures