HR: 0800h
AN: H11C-0637    [Abstracts]
TI: pH Control for Effective Anaerobic Bioremediation of Chlorinated Solvents
AU: * Robinson, C
EM: clare.robinson@epfl.ch
AF: Ecological Engineering Laboratory, Ecole Polytechnique Federale de Lausanne, Lausanne, CH-1015, Switzerland
AU: Barry, D
EM: andrew.barry@epfl.ch
AF: Ecological Engineering Laboratory, Ecole Polytechnique Federale de Lausanne, Lausanne, CH-1015, Switzerland
AU: Gerhard, J I
EM: j.gerhard@ed.ac.uk
AF: Institute for Infrastructure and Environment, School of Engineering and Electronics, University of Edinburgh, Edinburgh, EH9 3JL, United Kingdom
AU: Kouznetsova, I
EM: Irina.Kouznetsova@ed.ac.uk
AF: Institute for Infrastructure and Environment, School of Engineering and Electronics, University of Edinburgh, Edinburgh, EH9 3JL, United Kingdom
AB: SABRE (Source Area BioREmediation) is a 4-year collaborative project that aims to evaluate the performance of enhanced anaerobic bioremediation for the treatment of chlorinated solvent DNAPL source areas. The project focuses on a pilot scale demonstration at a trichloroethene (TCE) DNAPL field site, and includes complementary laboratory and modelling studies. Organic acids and hydrogen ions (HCl) typically build up in the treatment zone during anaerobic bioremediation. In aquifer systems with relatively low buffering capacity the generation of these products can cause significant groundwater acidification thereby inhibiting dehalogenating activity. Where the soil buffering capacity is exceeded, addition of buffer may be needed for the effective continuation of TCE degradation. As an aid to the design of remediation schemes, a geochemical model was designed to predict the amount of buffer required to maintain the source zone pH at a suitable level for dechlorinating bacteria (i.e. > 6.5). The model accounts for the amount of TCE to be degraded, site water chemistry, type of organic amendment and soil mineralogy. It assumes complete dechlorination of TCE, and further considers mineral dissolution and precipitation kinetics. The model is applicable to a wide range of sites. For illustration we present results pertinent to the SABRE field site. Model results indicate that, for the extensive dechlorination expected in proximity to the SABRE DNAPL source zone, significant buffer addition may be necessary. Additional simulations are performed to identify buffer requirements over a wider range of field conditions.
DE: 1831 Groundwater quality
DE: 3610 Geochemical modeling (1009, 8410)
SC: Hydrology [H]
MN: 2007 Fall Meeting