Browsing by Subject "Explosives"
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Item Aerobic biodegradation of HMX (Octahydro-1,3,5,7-Tetranitro-1,3,5,7-Tetrazocine) with a supplemental study of RDX (Hexahydro-1,3,5-Trinitro-1,3,5-Triazine)(Texas Tech University, 1998-05) Harkins, Victoria A. R.The Pantex facility near Amarillo, Texas, has soil and groundwater contaminated with differing combinations of high explosives (HEs), solvents, and metals. This study is concerned with the treatment of one HE, HMX in produced groundwater. Several physical and chemical treatment schemes for the treatment of HMX have been successful at other sites. These treatments include granular activated carbon adsorption, ultraviolet light radiation in combination with ozone, and alkaline hydrolysis. Successful biological treatment of HMX has been limited to anaerobic environments. Aerobic biodegradation is more desirable because of low capital and operation costs compared to those normally associated with anaerobic treatment. The objective of this work was to identify combinations of microbial consortia and amendments capable of aerobically biodegrading HMX. Once a treatment scheme was identified to breakdown HMX, a supplemental study was undertaken to determine the effects the same conditions would have on RDX, another HE contaminant of concem at Pantex.Item Bioremediation of explosives in vadose zone soil using vapor phase carbon source additions(Texas Tech University, 2005-05) Radtke, Corey W.; Cobb, George P.; Anderson, Todd; Dickerson, Richard L.; Roberto, Francisco F.Explosives contamination in vadose zone soil presents difficulties in remediation. Because vadose zone contamination can extend deep into the subsurface and underneath existing buildings and utilities, excavation is often infeasible. In response, this dissertation focuses on the development and testing of a practical system to enhance the remediation of vadose zone explosives contamination. Soil at the DOE Idaho National Engineering and Environmental Laboratory field area was characterized for explosives contamination. Of the soil tested, the particulate TNT retained on a 3 mm screen contributed approximately 2000 ppm (96.4%) of the overall soil contamination, compared to the soil that passed through the sieve, which averaged 75 ppm TNT. Contributing significantly to the contamination profile, heterogeneously dispersed, and likely point sources of contamination, the particulates thereby present difficulties in estimating the extent, risk, and treatability of explosives contamination in the soil. For monitoring soil gases, a method was developed and validated using solid phase microextraction coupled with gas chromatography and mass selective detection (SPME-GCMS). The within-run precision (repeatability) was 3.5X tighter than the between-run precision (reproducibility) in the 4 days. The esters gave the best repeatability from 50 to 80 ppmv while the corresponding alcohols gave the best results at 10 to 20 ppmv. The method was applied to monitor gases in laboratory and field studies testing explosives remediation in vadose zone soil. Anaerobic and microaerobic batch and column studies using soil from the DOE Pantex Facility contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 1,3,5-trinitrobenzene (TNB) were performed using gaseous carbon source additions. In the anaerobic batch study, over 99 days, flasks periodically receiving headspace pulses of 330 to 570 ppmv n-propyl acetate yielded 97.5±0.3% TNB and 66.7±43.2% RDX removal. Using ethanol in place of n-propyl acetate yielded similar results. Two column studies were performed using throughputs of oxygen, nitrogen gas, and organic carbon combinations. The columns supported less robust HE degradation than the batch systems. This difference in HE degradation between batch and column work may indicate that a key factor accumulated in the headspace of batch flasks, but was continually removed in the columns.Item In-situ degradation of high explosives(Texas Tech University, 1999-08) Brown, Justin HeathThe purpose of this research is to develop an in situ method to biodegrade high explosives in the vadose zone. The research project involves the construction of an experimental field site to force an anaerobic treatment zone and thus stimulate indigenous microorganisms to biodegrade the HE. The desired level of treatment is to reduce the HE concentrations to below the RRS2 values.Item Laboratory investigation of explosives degradation in vadose zone soil using carbon source additions(2005-05) Radtke, Corey William; Cobb, George P.; Anderson, Todd A.; Dickerson, Richard L.; Roberto, Francisco F.Explosives contamination in vadose zone soil presents difficulties in remediation. Because vadose zone contamination can extend deep into the subsurface and underneath existing buildings and utilities, excavation is often infeasible. In response, this dissertation focuses on the development and testing of a practical system to enhance the remediation of vadose zone explosives contamination. Soil at the DOE Idaho National Engineering and Environmental Laboratory field area was characterized for explosives contamination. Of the soil tested, the particulate TNT retained on a 3 mm screen contributed approximately 2000 ppm (96.4%) of the overall soil contamination, compared to the soil that passed through the sieve, which averaged 75 ppm TNT. Contributing significantly to the contamination profile, heterogeneously dispersed, and likely point sources of contamination, the particulates thereby present difficulties in estimating the extent, risk, and treatability of explosives contamination in the soil. For monitoring soil gases, a method was developed and validated using solid phase microextraction coupled with gas chromatography and mass selective detection (SPME-GCMS). The within-run precision (repeatability) was 3.5X tighter than the between-run precision (reproducibility) in the 4 days. The esters gave the best repeatability from 50 to 80 ppmv while the corresponding alcohols gave the best results at 10 to 20 ppmv. The method was applied to monitor gases in laboratory and field studies testing explosives remediation in vadose zone soil. Anaerobic and microaerobic batch and column studies using soil from the DOE Pantex Facility contaminated with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and 1,3,5-trinitrobenzene (TNB) were performed using gaseous carbon source additions. In the anaerobic batch study, over 99 days, flasks periodically receiving headspace pulses of 330 to 570 ppmv n-propyl acetate yielded 97.5±0.3% TNB and 66.7±43.2% RDX removal. Using ethanol in place of n-propyl acetate yielded similar results. Two column studies were performed using throughputs of oxygen, nitrogen gas, and organic carbon combinations. The columns supported less robust HE degradation than the batch systems. This difference in HE degradation between batch and column work may indicate that a key factor accumulated in the headspace of batch flasks, but was continually removed in the columns.Item Laboratory studies indicating the potential for bioremediation of high explosives in soil at the Pantex Plant(Texas Tech University, 1998-12) Medlock, Walter NThe main purpose of this thesis is to provide information in support ofthe field study. In May of 1998, eight, 30-ft wells were constmcted at the field study site to facilitate the gas injection and extraction procedure. The core samples from these wells were preserved and transported to Texas Tech University where they were analyzed with the following objectives in mind: (1) delineate the extent of HE contamination at the field study site, (2) determine if microbial (metabolic) activity is present in the soil, (3) enumerate the anaerobic microbial population, and (4) examine the relationships among HE concentration, metabolic activity, and microbial population.