15 research outputs found
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Microbiological Analysis of an Active Pilot-Scale Mobile Bioreactor Treating Organic Contaminants
Samples were obtained for microbiological analysis from a granular activated carbon fluidized bed bioreactor (GAC-FBR). This GAC-FBR was in operation at a former manufactured gas plant (MGP) Site in Augusta Georgia for in situ groundwater bioremediation of organics. The samples included contaminated site groundwater, GAC-FBR effluent, and biofilm coated granular activated carbon at 5, 9, and 13 feet within the GAC-FBR column. The objective of this analysis was to correlate contaminant removal with microbiological activity within the GAC-FBR
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Biodegradation of trichlorofluoromethane by sediment associated anaerobic bacteria from an aquifer contaminated by landfill leachate
The halogenated aliphatic hydrocarbon trichlorofluoromethane has been widely used as a refrigerant and aerosol propellant
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Fluorescent antibody application in bioremediation procedures at the Savannah River Site
Direct Fluorescent Antibodies (DFA) and Most Probable Number (MPN) techniques are currently being employed at the Savannah River Site to monitor methanotrophic bacteria for the bioremediation of trichloroethylene (TCE) in field studies. Direct Fluorescent Antibodies were developed against various methanotrophic bacteria isolated from SRS as well as methanotrophic bacteria acquired from the American Type Culture Collection (ATCC). DFA`s are anticipated to be more efficient for monitoring methanotroph activity than MPN`s because of shorter processing time, lower cost, and the direct nature of the assay. The DFA method is a direct technique, in that samples are processed immediately and can be enumerated within an hour. The MPN method is indirect, since samples must be cultured for 6-8 weeks before measuring methane consumption and carbon dioxide production. Indirect methods are not highly selective and have limited application. The greatest advantage of a faster assay, is that bioremediation procedures utilizing methanotrophic bacteria could be amended. These amendments would be based on environmental monitoring with results in real time (1 hour). The elimination of the MPN technique and the use of DFA`s will save significantly on both materials and labor. The data obtained from the DFA`s and MPN`s were statistically compared to each other and to total bacterial counts (AODC). The statistical analysis used was Analysis of Variants (ANOVA). Using this analysis, groundwater samples were found to be not significantly different; whereas soil were significantly different. These methods were employed on soil samples from the Southern Sector and ground water samples from the TCE-contaminated Sanitary Landfill at SRS. Acridine Orange Direct Counts were compared to show relative differences between total bacterial and methanotroph population
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Preliminary technology report for Southern Sector bioremediation
This project was designed to demonstrate the potential of intrinsic bioremediation and phytoremediation in the Southern Sector of the A/M-Area at the Savannah River Site. A subsurface plume of trichloroethylene (TCE) and perchloroethylene (PCE) is present in the Lost Lake aquifer upgradient of the study site and is predicted to impact the area at some point in the future. The surface area along the Lost lake aquifer seep line where the plume is estimated to emerge was identified. Ten sites along the seep line were selected for biological, chemical, and contaminant treatability analyses. A survey was undertaken in this area to to quantify the microbial and plant population known to be capable of remediating TCE and PCE. The current groundwater quality upgradient and downgradient of the zone of influence was determined. No TCE or PCE was found in the soils or surface water from the area tested at this time. A TCE biodegradation treatability test was done on soil from the 10 selected locations. From an initial exposure of 25 ppm of TCE, eight of the samples biodegraded up to 99.9 percent of all the compound within 6 weeks. This biodegradation of TCE appears to be combination of aerobic and anaerobic microbial activity as intermediates that were detected in the treatability test include vinyl chloride (VC) and the dichloroethenes (DCE) 1,2-cis-dichloroethylene and 1,1-dichloroethylene. The TCE biological treatability studies were combines with microbiological and chemical analyses. The soils were found through immunological analysis with direct fluorescent antibodies (DFA) and microbiological analysis with direct fluorescent antibodies (DFA) and microbiological analysis to have a microbial population of methanotrophic bacteria that utilize the enzyme methane monooxygenase (MMO) and cometabolize TCE
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Direct immunofluorescence and enzyme-linked immunosorbent assays for evaluating chlorinated hydrocarbon degrading bacteria
Immunological procedures were developed to enumerate chlorinated hydrocarbon degrading bacteria. Polyclonal antibodies (Pabs) were produced by immunizing New Zealand white rabbits against 18 contaminant-degrading bacteria. These included methanotrophic and chlorobenzene (CB) degrading species. An enzyme-linked immunosorbent assay (ELISA) was used to test for specificity and sensitivity of the Pabs. Direct fluorescent antibodies (DFAs) were developed with these Pabs against select methanotrophic bacteria isolated from a trichloroethylene (TCE) contaminated landfill at the Savannah River Site (SRS) and cultures from the American Type Culture Collection (ATCC). Analysis of cross reactivity testing data showed some of the Pabs to be group specific while others were species specific. The threshold of sensitivity for the ELISA is 105 bacteria cells/ml. The DFA can detect as few as one bacterium per ml after concentration. Results from the DFA and ELISA techniques for enumeration of methanotrophic bacteria in groundwater were higher but not significantly different (P < 0.05) compared to indirect microbiological techniques such as MPN. These methods provide useful information on in situ community structure and function for bioremediation applications within 1--4 hours of sampling
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Identification of Thiothrix unzii in Two Distinct Ecosystems
Molecular procedures were used to identify Thiothrix spp. in biofilms from sulfide-rich waters in two distinct Florida ecosystems. These Thiothrix spp.-containing biofilms at these sites have been consistently observed for over 10 years. Clonal libraries of biofilm 16S rDNA from each site contained rDNA sequences that were 99 to 99.5 percent similar to Thiothrix unzii
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Fiscal Year 2001
This treatability study is now in the second year of deployment for the Southern Sector Phytoremediation Project. Phytoremediation is the use of vegetation and associated media to treat contaminated soils, sediments, and groundwater. Phytoremediation is a rapidly developing technology that promises effective and safe cleanup of certain hazardous wastes. This ongoing work addresses the fate of volatile organic contaminants (VOCs) in an experiment that simulates a vegetated seepline supplied with trichloroethylene- (TCE-) and perchloroethylene- (PCE-) contaminated groundwater. The primary objective is to determine how the trees and sediments uptake groundwater TCE and PCE, biodegrade it, and/or transform it. The experimental focus of this project is the biological removal of VOCs from seepline groundwater and sediments
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Characterization of Microbial Communities from Pristine and Chlorinated-Ethene-Contaminated Landfill Groundwater
Molecular, phospholipid fatty acid analysis (PLFA), and substrate utilization (BIOLOG) techniques were used to assess structural and functional differences between microbial communities from a chlorinated-ethene (CE)-contaminated groundwater at a sanitary landfill. The information will be used to evaluate natural attenuation of the associated CE plume. Two groundwater-monitoring wells were tested
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Characterization of Groundwater Microbial Communities from a Chlorinated-Ethene-Contaminated Landfill
Molecular (rDNA), phospholipid fatty acid analysis (PLFA), and substrate utilization (BIOLOG) techniques were used to assess structural and functional differences between groundwater microbial communities from a chlorinated-ethene (CE)-contaminated landfill. Prokaryotic cells were collected from pristine (LFW 43B) and CE-contaminated (LFW 62D) groundwater monitoring wells on 0.2 micron filters, DNA was extracted from the filters, and libraries were prepared. For well LFW 43B, 26 clones were examined by sequencing and restriction endonuclease patterns, and all were found to be closely related to Pseudomonas gessardii and P. libaniensis. For well LFW 62D, 40 bacterial clones were examined, and 17 ribotypes were found including representatives of type I and II methylotrophs, Pseudomonas spp., Zoogloea spp., and other proteobacteria. In an archaeal library from well LFW 62D, all 15 of the clones examined were nearly identical and possessed about 89 percent sequence similarity to Cenarchaeum symbiosum. PLFA analysis revealed that the communities from contaminated groundwater contained primarily gram-negative bacteria, as indicated by the predominance of the biomarker 16:1w7c. The bacteria were in the stationary growth phase as indicated by the abundance of cyclopropyl fatty acids cy17:0 and cy19:0 and their respective precursors 16:1w7c and 18:1w7c. Further, PLFA ratios for 16:1w7t/16:1w7c and 18:1w7t/18:1w7c were greater than 0.1, indicative of increased cellular membrane permeability. Using BIOLOG GN plates, a similar number of substrates were utilized in LFW43B (72) and LFW 62D (63) communities, even though inoculum densities were 2-orders of magnitude greater in LFW 62D. The combination of non-selective characterization techniques was useful to further our understanding of CE-contamination on groundwater microbial communities
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Biofouling of groundwater distribution systems by Thiothrix spp.
Thiothrix spp., sulfide oxidizing filamentous bacteria, were found to be the main bacterial component of aquatic biofilms causing biofouling in selected municipal water storage tanks, private wells, and drip irrigation systems in Florida. The water originated from the upper Floridan aquifer and associated aquifers in Central and North Florida. Samples were examined where visible biofilms had a white, slimy, filamentous appearance indicative of Thiothrix spp. The detection of Thiothrix spp. was confirmed by enzyme-liked immunosorbent assay (ELISA). These observations confirm that these bacteria and associated extracellular material play an important role in formation of biofilms, which in turn may induce physical changes leading to significant biofouling. These studies suggest that Thiothrix spp.-associated biofouling occurs at an interface where reduced sulfide-containing water contacts aerated water and a surface or substrate is available for attachment