Effect of surface coatings, grain size, and ionic strength on the maximum attainable coverage of bacteria on sand surfaces.
J Contam Hydrol
; 50(3-4): 287-305, 2001 Aug.
Article
en En
| MEDLINE
| ID: mdl-11523329
The injection of bacteria in the subsurface has been identified as a potential method for in situ cleanup of contaminated aquifers. For high bacterial loadings, the presence of previously deposited bacteria can result in decreased deposition rates--a phenomenon known as blocking. Miscible displacement experiments were performed on short sand columns (approximately 5 cm) to determine how bacterial deposition on positively charged metal-oxyhydroxide-coated sands is affected by the presence of previously deposited bacteria. Approximately 8 pore volumes of a radiolabeled bacterial suspension at a concentration of approximately 1 x 10(9) cells ml-1 were introduced into the columns followed by a 2-pore-volume flush of cell-free buffer. It was found that the presence of Al- and Fe-coated sand increased both deposition rates and maximum fractional surface coverage of bacteria on the sediment surfaces. The effect of grain size on maximum bacterial retention capacity, however, was not significant. Decreasing ionic strength from 10(-1) to 10(-2) M KCl resulted in noticeable decreases in sticking efficiency (alpha) and maximum surface coverage (thetamax) for clean silica sand--results consistent with DLVO theory. In columns containing positively charged Al- and Fe-coated sands, however, changes in alpha and thetamax due to decreasing ionic strength were minimal. These findings demonstrate the importance of geochemical controls on the maximum bacterial retention capacity of sands.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Microbiología del Suelo
/
Contaminantes del Suelo
/
Contaminantes Químicos del Agua
/
Dióxido de Silicio
/
Aluminio
/
Hierro
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
J Contam Hydrol
Asunto de la revista:
TOXICOLOGIA
Año:
2001
Tipo del documento:
Article
País de afiliación:
Estados Unidos
Pais de publicación:
Países Bajos