Publications

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Microbial biomass can clog porous media and ultimately affect both structural and mineral trapping of CO2 in geological carbon storage reservoirs. Whether biomass can remain intact following a sudden decrease in groundwater pH, a geochemical change associated with CO2 injection, is unclear. We examined this question using twelve biologically-active and three control column-reactor experiments. Cell abundance and distribution was monitored using confocal microscopy, plating, and direct counting. Hydraulic conductivity (K) was monitored using pressure sensors. Growth occurred for four days at neutral pH. During that time, K within the clogged portion of the reactors decreased from 0.013 to 0.0006cm s-1 on average, a 1.47log reduction. Next, the pH of the inflowing aqueous medium was lowered to pH 4 in six experiments and pH 5.7 in six experiments. As a result, K increased in five of the pH 4 experiments and two of the pH 5.7 experiments. Despite this increase, however, the columns remained largely clogged. Compared to pre-inoculation K values, log reductions averaged 1.13 and 1.44 in pH 4 and pH 5.7 experiments, respectively. Our findings show that biomass can largely remain intact following acidification and continue to reduce K, even when considerable cell stress and death occurs. © 2012 Elsevier Ltd.

Ceragenins were used to create biofouling resistant water-treatment membranes. Ceragenins are synthetically produced antimicrobial peptide mimics that display broad-spectrum bactericidal activity. While ceragenins have been used on bio-medical devices, use of ceragenins on water-treatment membranes is novel. Biofouling impacts membrane separation processes for many industrial applications such as desalination, waste-water treatment, oil and gas extraction, and power generation. Biofouling results in a loss of permeate flux and increase in energy use. Creation of biofouling resistant membranes will assist in creation of clean water with lower energy usage and energy with lower water usage. Five methods of attaching three different ceragenin molecules were conducted and tested. Biofouling reduction was observed in the majority of the tests, indicating the ceragenins are a viable solution to biofouling on water treatment membranes. Silane direct attachment appears to be the most promising attachment method if a high concentration of CSA-121a is used. Additional refinement of the attachment methods are needed in order to achieve our goal of several log-reduction in biofilm cell density without impacting the membrane flux. Concurrently, biofilm forming bacteria were isolated from source waters relevant for water treatment: wastewater, agricultural drainage, river water, seawater, and brackish groundwater. These isolates can be used for future testing of methods to control biofouling. Once isolated, the ability of the isolates to grow biofilms was tested with high-throughput multiwell methods. Based on these tests, the following species were selected for further testing in tube reactors and CDC reactors: Pseudomonas ssp. (wastewater, agricultural drainage, and Colorado River water), Nocardia coeliaca or Rhodococcus spp. (wastewater), Pseudomonas fluorescens and Hydrogenophaga palleronii (agricultural drainage), Sulfitobacter donghicola, Rhodococcus fascians, Rhodobacter katedanii, and Paracoccus marcusii (seawater), and Sphingopyxis spp. (groundwater). The testing demonstrated the ability of these isolates to be used for biofouling control testing under laboratory conditions. Biofilm forming bacteria were obtained from all the source water samples.

Marine Hydrokinetic energy is the production of renewable electricity converted from the kinetic energy of ocean waves, current, tides, or by thermal gradients. Currently an emerging global industry is focused on developing novel technology to harness this sustainable power. These alternative energy devices require advances in anticorrosion and antibiofouling coatings to enhance lifetime and performance. In order to understand the microbial-nanomaterial interaction as well as nanomaterial corrosion process, we have elected to examine a variety of metallic, oxide and phosphate based nanomaterials. The synthesis of these materials using solution precipitation and solovothermal routes along with their full characterization will be presented.

Abstract not provided.

Abstract not provided.

Abstract not provided.

Injection of CO{sub 2}-laden flue gas can decrease the potential for silica and calcite scale formation in cooling tower blowdown by lowering solution pH to decrease equilibrium calcite solubility and kinetic rates of silica polymerization. Flue gas injection might best inhibit scale formation in power plant cooling towers that use impaired makeup waters - for example, groundwaters that contain relatively high levels of calcium, alkalinity, and silica. Groundwaters brought to the surface for cooling will degas CO{sub 2} and increase their pH by 1-2 units, possibly precipitating calcite in the process. Recarbonation with flue gas can lower the pHs of these fluids back to roughly their initial pH. Flue gas carbonation probably cannot lower pHs to much below pH 6 because the pHs of impaired waters, once outgassed at the surface, are likely to be relatively alkaline. Silica polymerization to form scale occurs most rapidly at pH {approx} 8.3 at 25 C; polymerization is slower at higher and lower pH. pH 7 fluids containing {approx}220 ppm SiO{sub 2} require > 180 hours equilibration to begin forming scale whereas at pH 8.3 scale formation is complete within 36 hours. Flue gas injection that lowers pHs to {approx} 7 should allow substantially higher concentration factors. Periodic cycling to lower recoveries - hence lower silica concentrations - might be required though. Higher concentration factors enabled by flue gas injection should decrease concentrate volumes and disposal costs by roughly half.

Abstract not provided.

Abstract not provided.