摘要:

Injection of bacteria with petroleum degrading capability into contaminated sites is one of the most cost-effective and environmental friendly strategies for the successful remediation of petroleum-contaminated groundwater. The successful in-situ bioremediation of petroleum contamination in subsurface is greatly impacted by the mobile/retention performance of petroleum-degrading bacteria in porous media, which yet is not well understood. The present study systematically investigated the mobile performance of petroleum-degrading strains in porous media with petroleum contamination under environmentally relevant solution and flow conditions. We found that although the mobile performance of petroleum-degrading bacteria was similar to petroleum non-degrading bacteria in uncontaminated porous media, bacteria containing different petroleum degrading function yet exhibited opposite transport behaviors in petroleum contaminated porous media. Enhanced mobility in porous media with petroleum contamination was achieved for petroleum non-degrading bacteria, while reduced mobility was obtained for petroleum-degrading bacteria. Combining the batch adsorption experiments, capillary chemotaxis assays, in-situ microfluidic chamber experiments together with theoretical calculation, we found that the opposite mobile performance observed for bacteria containing different petroleum degrading functions could be mainly attributed to their different chemotactic responses towards petroleum with negative and positive chemotaxis response respectively for non- and petroleum-degrading bacteria. Clearly, pollutant-degrading bacteria exhibited different mobile performance from non-degrading bacteria in contaminated porous media. The previous findings achieved from the model bacteria without pollutant-degrading capability could not be simply used to predict the mobile performance of pollutant-degrading bacteria. To ensure the successful implementation of in-situ bioremediation, the mobility of pollutant-degrading bacteria in contaminated porous media should be fully understood.

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