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Biochemical ripening of dredged sediments. Part 1. Kinetics of biological organic matter mineralization and chemical sulfur oxidation

Authors

  • Johan Vermeulen,

    1. Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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  • Martine P. M. van Gool,

    1. Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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  • Arne S. Dorleijn,

    1. Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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  • Jan Joziasse,

    1. Business Unit Subsurface and Groundwater, TNO Built Environment and Geosciences, P.O. Box 80015, 3508 TA Utrecht, The Netherlands
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  • Harry Bruning,

    1. Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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  • Wim H. Rulkens,

    1. Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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  • J. T. C. (Tim) Grotenhuis

    Corresponding author
    1. Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
    Current affiliation:
    1. Published on the Web 7/11/2007
    • Sub-department of Environmental Technology, Wageningen University, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
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Abstract

After dredged sediments have settled in a temporary upland disposal site, ripening starts, which turns waterlogged sediment into aerated soil. Aerobic biological mineralization of organic matter (OM) and chemical oxidation of reduced sulfur compounds are the major biochemical ripening processes. Quantitative data describing these processes are scarce. Therefore, aerobic oxidation and mineralization of five previously anaerobic dredged sediments were studied during a 160-d laboratory incubation experiment at 30°C. A double exponential decay model could adequately describe sulfur oxidation and OM mineralization kinetics. During the first 7 d of incubation, 23 to 80% of the total sulfur was oxidized, after which no further sulfur oxidation was observed. Oxygen used for sulfur oxidation amounted up to 95% of the total oxygen uptake in the first 7 d and up to 45% of the oxygen uptake during the entire incubation period. Mineralization rates of the rapidly mineralizable OM fractions that degraded during the first 14 to 28 d of incubation were 102 to 103 times higher than the mineralization rates of the slowly mineralizable OM during the remaining period. First-order mineralization rates of the slowly mineralizable OM were 0.22 × 10−3 to 0.54 × 10−3 d−1 and can be compared with those of terrestrial soils. Yields of biomass on substrate ranged from 0.08 to 0.45 g Cbiomass/g COM and appeared to be higher for rapidly mineralizing OM than for slowly mineralizing OM. The results of this study can be used to optimize conditions during temporary disposal of sediments, to estimate the potential decrease in OM, and for future studies on the possible link between OM mineralization and degradation of hydrophobic organic contaminants.

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