Browsing by Author "Bouwer, Edward J."

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Biofilms in porous media
(2000) Bouwer, Edward J.; Rijnaarts, Huub H. M.; Cunningham, Alfred B.; Gerlach, Robin
Degradation of xenobiotic compounds in situ: capabilities and limits
(1994-10) Bouwer, Edward J.; Durant, N.; Wilson, L.; Zhang, Weiyan; Cunningham, Alfred B.
Exploiting microorganisms for remediation of waste sites is a promising alternative to groundwater pumping and above ground treatment. The objective of in situ bioremediation is to stimulate the growth of indigenous or introduced microorganisms in regions of subsurface contamination, and thus to provide direct contact between microorganisms and the dissolved and sorbed contaminants for biotransformation. Subsurface microorganisms detected at a former manufactured gas plant site contaminated with coal tars mineralized significant amounts of naphthalene (8–43%) and phenanthrene (3–31%) in sediment-water microcosms incubated for 4 weeks under aerobic conditions. Evidence was obtained for naphthalene mineralization (8–13%) in the absence of oxygen in field samples. These data suggest that biodegradation of these compounds is occurring at the site, and the prospects are good for enhancing this biodegradation. Additional batch studies demonstrated that sorption of naphthalene onto aquifer materials reduced the extent and rate of biodegradation, indicating that desorption rate was controlling the biodegradation performance.
Engineering scale-up of in situ bioremediation processes: a review
(1995-09) Sturman, Paul J.; Stewart, Philip S.; Cunningham, Alfred B.; Bouwer, Edward J.; Wolfram, James H.
To be useful to field practitioners, advances in bioremediation research must be capable of being scaled up from the laboratory to the field. The phenomena which control the rate at which biodegradation proceeds are typically scale-dependent in nature. Failure to understand and account for scale-dependent variables, such as mass transport limitations, spatial heterogeneities and the presence of competing microorganisms, may inhibit the effectiveness of field-scale bioremediation designs. This paper reviews and evaluates the methods available for characterization of the processes effecting bioremediation at scales ranging from the laboratory to the field. Questions facing the field-scale practitioner of bioremediation are addressed in a manner which highlights the current state of research, the reliability of results and the extent to which laboratory-scale research accurately reflects common field conditions. Where gaps or inadequacies exist in our current knowledge or methods, research needs are identified. This review is intended to complement existing work by providing a framework from which to assess the importance of scale of observation to a particular result or conclusion, thereby providing an integrated approach to the scale-up process.