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Nanoscale zerovalent iron (NZVI) is used for groundwater remediation. Freshly synthesized bare, i.e. uncoated NZVI is bactericidal at low mg/L concentration, but the impact of surface modifiers and aging (partial oxidation) on its bactericidal properties have not been determined. Here we assess the effect that adsorbed synthetic polymers and natural organic(More)
It has been demonstrated previously that Geobacter species can transfer electrons directly to electrodes. In order to determine whether electrodes could serve as electron donors for microbial respiration, enrichment cultures were established from a sediment inoculum with a potentiostat-poised graphite electrode as the sole electron donor and nitrate as the(More)
RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), a nitramine explosive, is often found as a subsurface contaminant at military installations. Though biological transformations of RDX are often reported, abiotic studies in a defined medium are uncommon. The work reported here was initiated to investigate the transformation of RDX by ferrous iron (Fe(II))(More)
Shewanella oneidensis MR-1 grew for over 50 days in microbial fuel cells, incompletely oxidizing lactate to acetate with high recovery of the electrons derived from this reaction as electricity. Electricity was produced with lactate or hydrogen and current was comparable to that of electricigens which completely oxidize organic substrates. However, unlike(More)
Microbial communities associated with produced water from hydraulic fracturing are not well understood, and their deleterious activity can lead to significant increases in production costs and adverse environmental impacts. In this study, we compared the microbial ecology in prefracturing fluids (fracturing source water and fracturing fluid) and produced(More)
Hydraulic fracturing for natural gas extraction from shale produces waste brine known as flowback that is impounded at the surface prior to reuse and/or disposal. During impoundment, microbial activity can alter the fate of metals including radionuclides, give rise to odorous compounds, and result in biocorrosion that complicates water and waste management(More)
Microbial activity in produced water from hydraulic fracturing operations can lead to undesired environmental impacts and increase gas production costs. However, the metabolic profile of these microbial communities is not well understood. Here, for the first time, we present results from a shotgun metagenome of microbial communities in both hydraulic(More)
Nanoscale zerovalent iron (NZVI) particles are a promising technology for reducing trichloroethylene (TCE) contamination in the subsurface. Prior to injecting large quantities of nanoparticles into the groundwater it is important to understand what impact the particles will have on the geochemistry and indigenous microbial communities. Microbial populations(More)
Previous studies have demonstrated that Geobacter species can effectively remove uranium from contaminated groundwater by reducing soluble U(VI) to the relatively insoluble U(IV) with organic compounds serving as the electron donor. Studies were conducted to determine whether electrodes might serve as an alternative electron donor for U(VI) reduction by a(More)
Increasing use of engineered nanomaterials with novel properties relative to their bulk counterparts has generated a need to define their behaviors and impacts in the environment. The high surface area to volume ratio of nanoparticles results in highly reactive and physiochemically dynamic materials in environmental media. Many transformations, e.g.(More)