Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Ruimte voor kwaliteit en ondernemerschap : Wageningen Universiteits & Researchcentrum, Instellingsplan Wageningen Universiteit, Ondernemingsplan Stichting DLO, 2003-2006
    Bartelink, H.H. ; Berlo, J.M. van; Bouma, J. ; Gooijer, C.D. de; Groen, A.F. ; Groot, R. ; Jongebreur, A.A. ; Klerk-Engels, B. de; Oorschot, R. ; Schlebaum, W. - \ 2003
    Wageningen : Wageningen UR - 69
    hogere agrarische scholen - universiteiten - hoger onderwijs - agrarisch onderwijs - onderwijshervorming - onderwijsvernieuwing - onderwijsplanning - personeel - landbouwkundig onderzoek - onderzoek - financieren - organisatieontwikkeling - planning - veluwe - gelderland - nederland - agricultural colleges - universities - higher education - agricultural education - educational reform - educational innovation - educational planning - personnel - agricultural research - research - financing - organizational development - planning - veluwe - gelderland - netherlands
    Influence of nonlinear sorption kinetics on the slow-desorbing organic contaminant fraction in soil
    Schlebaum, W. ; Schraa, G. ; Riemsdijk, W.H. van - \ 1999
    Environmental Science and Technology 33 (1999)9. - ISSN 0013-936X - p. 1413 - 1417.
    Release rates of hydrophobic organic compounds (HOCs) from the soil matrix influence the availability of HOCs in soils or sediments for microbial degradation or removal by physical means (e.g., soil washing or soil venting). In this study it was shown that the initial contaminant concentration influences the desorption rate. This was attributed to the presence of a limited number of high affinity sites that cause nonlinear sorption behavior. The experimental results could be described with a kinetic model composed of two separate compartments. One compartment was described with a Freundlich isotherm and corresponding kinetics and was assumed to represent sorption to high affinity sites. The second compartment was described with a linear sorption isotherm and first-order kinetics. The model was used to simulate the influence of purging strategies on removal of QCB. The simulations showed that after removal of a fast-desorbing fraction, the slow-desorbing fraction could be efficiently removed at very low purging rates. Intermittent purging reduced the total purging time but the simulations showed large fluctuations in the aqueous pentachlorobenzene concentration. For each subsequent purging interval, the purging efficiency decreased due to the nonlinear desorption kinetics of the slow-desorbing fraction of pentachlorobenzene. | Release rates of hydrophobic organic compounds (HOCs) from the soil matrix influence the availability of HOCs in soils or sediments for microbial degradation or removal by physical means (e.g., soil washing or soil venting). In this study it was shown that the initial contaminant concentration influences the desorption rate. This was attributed to the presence of a limited number of high affinity sites that cause nonlinear sorption behavior. The experimental results could be described with a kinetic model composed of two separate compartments. One compartment was described with a Freundlich isotherm and corresponding kinetics and was assumed to represent sorption to high affinity sites. The second compartment was described with a linear sorption isotherm and first-order kinetics. The model was used to simulate the influence of purging strategies on removal of QCB. The simulations showed that after removal of a fast-desorbing fraction, the slow-desorbing fraction could be efficiently removed at very low purging rates. Intermittent purging reduced the total purging time but the simulations showed large fluctuations in the aqueous pentachlorobenzene concentration. For each subsequent purging interval, the purging efficiency decreased due to the nonlinear desorption kinetics of the slow-desorbing fraction of pentachlorobenzene.
    Organic contaminants in soil : desorption kinetics and microbial degradation
    Schlebaum, W. - \ 1999
    Agricultural University. Promotor(en): W.H. van Riemsdijk; G. Schraa. - S.l. : Schlebaum - ISBN 9789058080219 - 89
    sorptie - biodegradatie - kinetica - organische verbindingen - besmetters - sorption - biodegradation - kinetics - organic compounds - contaminants

    The availability of organic contaminants in soils or sediments for microbial degradation or removal by physical means (e.g.) soil washing or soil venting) depends on the desorption kinetics of these contaminants from the soil matrix. When the organic contaminants desorb very slow from the soil matrix, remediation of polluted sites may be hampered. In this thesis, sorption kinetics of organic contaminants in soil was investigated with emphasis on the influence of natural organic matter on slow desorption rates, and the influence of sorption kinetics on the microbial degradation rates of these contaminants. Two organic matter fractions, humic acids and humin, were shown not only to differ in their affinity for an organic contaminant, but also in the kinetics of their interactions with the contaminant.

    The results showed that humin can play an important role in the sorption behaviour of a soil. Interaction between humic acids and an organic contaminant were shown to be non-linear. Non-linear sorption behaviour was also observed for soil. The effects of non-linear sorption behaviour were demonstrated in simulations. Non-linear sorption may be caused by a limited number of sites with a high sorption energy that are present in humin. Microbial degradation of an organic contaminant in soil was predicted using measured desorption kinetics and measured intrinsic microbial degradation kinetics. It was shown that only for the slow-desorbing contaminant fraction, the desorption rate was the rate-determining step for the degradation in soil.

    When microorganisms are able to degrade contaminants that become available by a slow desorption process, the natural degradation of organic contaminants in soil can be an efficient remediation method in the last stages of the in situ remediation of a contaminated soil. Continuous monitoring of such a contaminated soil however will be needed.

    Interactions between a hydrophobic chemical and natural organic matter: equilibrium and kinetic studies.
    Schlebaum, W. ; Badora, A. ; Schraa, G. ; Riemsdijk, W.H. van - \ 1998
    Environmental Science and Technology (1998). - ISSN 0013-936X - p. 2273 - 2277.
    Desorption kinetics of a hydrophobic organic compound from natural organic matter.
    Schlebaum, W. ; Schraa, G. ; Riemsdijk, W.H. van - \ 1996
    In: Abstract 8th IHSS Meeting on The role of humic substances in the ecosystem and in environmental protection, Wroclaw, Poland - p. 53 - 53.
    Desorptie van organische verbindingen uit de organische stoffractie van de bodem.
    Schlebaum, W. ; Schraa, G. ; Riemsdijk, W.H. van - \ 1995
    In: Bodem breed '95: Samenvattingen Nat. Symp. Bodemonderzoek, Lunteren - p. 138 - 138.
    Adsorption and desorption kinetics of a hydrophobic organic compound on natural organic matter.
    Schlebaum, W. ; Grotenbreg, E.W.A. ; Schraa, G. ; Riemsdijk, W.H. van - \ 1995
    In: Proc. 5th Int. FZK/TNO Conf. Contaminated soil, Maatricht / van den Brink, W.J., - p. 417 - 418.
    Desorptie van organische verontreinigingen uit de organische stoffractie van de bodem.
    Schlebaum, W. ; Grotenbreg, E.W.A. ; Smit, A. ; Schraa, G. ; Riemsdijk, W.H. van - \ 1994
    In: In: Bodem Breed, M.J. Lexmond (ed.). Verslag 6e Nationaal Symp. Bodemonderzoek, Lunteren. Programmabureau Bodemonderzoek, Wageningen - p. 57 - 57.
    Desorption of hydrophobic organic pollutants from soil organic matter.
    Schlebaum, W. ; Schraa, G. ; Riemsdijk, W.H. van - \ 1994
    In: IOP Milieubiotechnologie Symp. 4 jaar Vooruitgang & Verankering. Ede (1994)
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