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No description available.

No description available.

No description available.

Millions of tons of ash and slag are produced each year as a result of energy production. This study looks at the mineralogy and textures in the ash resulting from the gasification of a 25% Passaic Valley sewage sludge, 75% Pittsburgh #8 coal slurry in a Texaco gasification facility and at ash resulting from the incineration of municipal solid waste at several facilities in Virginia and North Carolina. This information is then compared with similar studies done on ash and slag from coal-burning power plants and a study done on petroleum coke slag which was produced at a Texaco gasification facility. Lastly, a comparison of bulk chemistries of ashes to those of soil and crustal rocks is made. A general understanding of the stability of elements, especially metals, in terms of the phases in which they are contained as well as the textures, was hoped to be gained from this study. Samples for this study were polished sections which were 2.54 em in diameter that were set in cold-setting epoxy then ground and polished. Samples were then studied under a reflected light microscope before being carbon coated for study on a SEM and an electron microprobe. Photos of textures and analyses were made throughout. At least 50% of the ash from all sources was a Si-Al oxide rich glass which had varying amounts of Fe, Ca, K, P, Mg, and Ti and other trace elements. Fe oxides and spinels were common phases found. Pb and Zn were rarely encountered, but were found as both oxides and sulfides. Cr was found in the form of spinels, often covered by a protective AI enriched outer rim. The heavy metals found were successfully bound as mineral analogs or as a glass phase. The only phase found to be reactive was an AIC matrix containing subhedral SiC crystals. The AI phase effervesced when placed in contact with water, changing from tan to greenlblue/violet in color, releasing a gas (probably CO₂, C2H2, or CH4) in the process. / Master of Science

Raw water samples from nine utilities were received, and water-quality analyses, bench-scale water treatment, and chlorination were performed to determine the effectiveness of enhanced coagulation at removal of dissolved organic carbon (DOC) and organic halide precursors. Bench-scale treatment included: 1) baseline treatment, defined as the coagulant dose and pH at which the specific utility's water treatment plant was operating on the day the samples were collected, and 2) enhanced treatment, which was determined on the basis of bench-scale studies. Enhanced treatment is defined in the proposed Disinfectant/Disinfection By-Products (D/DBP) Rule as the coagulant dose at which a 10 mg/L increase in coagulant dose does not produce greater than a 0.3 mg/L decrease in dissolved organic carbon (DOC) or total organic carbon (TOC) concentration over the previous dose (Federal Register 1994). The treated samples were then chlorinated and analyzed for disinfection by-products (DBPs), including trihalomethanes (THMs) and non-purgeable dissolved organic halides (NPDOX). Specific objectives included: 1) an evaluation of the effectiveness of enhanced coagulation for TOC reduction, 2) determination of the effectiveness of surrogate parameters: such as raw water DOC and specific ultraviolet absorbance (SUVA); for predicting TOC removal by enhanced coagulation, and 3) determination of the relationship between DOC and NPDOX concentration in raw and treated waters. For all of the utilities, enhanced coagulation was effective at meeting the proposed TOC removal requirements contained in the D/DBP Rule, which range from 20 percent to 50 percent removal based on the alkalinity and TOC of the raw water. Raw water SUVA was the best indicator of the expected Toe removal by enhanced coagulation, with raw water SUVA values > 3.0 L/mg-m typically indicating greater TOC removal. Organic content was a good indicator of DBP formation. The average non-purgeable dissolved organic halogen formation potential (NPDOXFP) yields, based on DOC, were 155 μg as Cl⁻/mg DOC for raw water samples and ranged from 110- 138 μg as CI⁻/mg DOC for treated water samples. / Master of Science

The objectives of this research were to develop a broad spectrum method for the extraction, concentration, and analysis of drinking water disinfection by products using solid phase extraction (SPE), and to determine if this method had lower detection limits and less variability than the proposed liquid-liquid extraction method, EPA Method 551. The disinfection by products investigated were halogenated nitriles, ketones, and aldehydes. The SPE method extracted and concentrated samples using the C-18 Empore Extraction Disks, and desorbed the analytes with methyl-tert-butyl ether (MTBE) as a solvent. The results showed that with the SPE method the recoveries were low (0-50%) for most compounds, and the limit of detection (LOD) values were in the range of 0.2 to 50 ug/L, which were much higher than those for EPA Method 551. The variability was also higher than for EPA Method 551. The SPE method also appeared to be concentration dependent; the recoveries decreased as analyte concentration increased. Highly saline conditions (250 g/L NaCl) resulted in low recoveries and concentration dependencies for some compounds. Even though the SPE method was easier and faster, the lower method detection limit (MDL) values and lower variability made Method 551 more preferable. Further analysis of the SPE method using a new cyclohexyl disk was also recommended. / Master of Science

M.S.

As the population in water stressed areas increases, it is critical that wastewater treatment plants (WWTPs) continue to replenish depleted water supplies, and serve as an alternative water source. WWTPs depend on microorganisms in activated sludge to remove pollutants from wastewater and therefore an understanding of how these microorganisms are affected by various conditions and pollutants is needed. Also, as consumer products and industrial processes evolve, so do the pollutants they discharge to wastewater. In order to keep pace with these changes, understanding the effects of emerging contaminants to WWTP processes is essential. The research herein assesses microbial community dynamics of the response of nitrifying microorganisms in activated sludge to variation in ammonia concentration and evaluates the impact of engineered nanoparticles on activated sludge microbial communities and other emerging pollutants, such as antibiotic resistance genes and disinfection by-products. In order to assess microbial community dynamics of the response of nitrifying microorganisms to removal of ammonia in the feed, nitrifying activated sludge reactors were operated at various relevant temperatures and the nitrifying microbial community was characterized using activity assays and bio-molecular techniques. We found that Nitrospira spp. were the dominant nitrifying microorganisms, exhibiting stable relative abundance across multiple trials and over a range of temperatures. These results indicate the possibility of comammox bacteria in the system and highlight the complexity of nitrifying microbial communities in activated sludge relative to past understanding. Both microbial and chemical impacts of engineered nanoparticles on WWTP processes were also investigated. Metagenomic analysis of DNA extracted from activated sludge sequencing batch reactors dosed with gold nanoparticles with varied surface coating and morphology indicated that nanoparticle morphology impacted the microbial community and antibiotic resistance gene content more than surface coating. However, nanoparticle fate was controlled by surface coating more than morphology. Disinfection by-product formation in the presence of nanoparticles during WWTP disinfection was assessed using silver, titanium dioxide, ceria, and zero valent iron nanoparticles. Silver nanoparticles were found to enhance trihalomethane formation, which was attributed to the citrate coating of the nanoparticles. These studies both raise concern over the relationship between engineered nanoparticles and other emerging concerns in WWTPs, and take a step towards informing nanoparticle design in a manner that limits their associated environmental impact. / Ph. D.

Reclaimed surface mined soils in Appalachia are typically infertile and must be amended for optimum vegetative growth. Fluidized bed combustion residue (FBCR), a by-product of coal-fired power plants, has high levels of Ca, S, Zn, Fe, and Al, and 50% of the neutralizing capacity of limestone. Three treatments were applied to three replicated .81 ha reclaimed mine pastures: control (no amendment), 6760 kg FBCR/ha, and 3380 kg limestone/ha. Based on forage availability, six steers were rotationally grazed on pastures receiving each treatment. Steers were weighed and blood samples collected at 14-d intervals and all animals were sacrificed for tissue sampling at the end of the 114-d trial. Amendment with FBCR or limestone increased soil pH (P < .05) above control levels. Forage yield and steer gain were not significantly affected by treatment. Forage samples collected during the trial indicated that FBCR and limestone amendments elevated forage ash, Ca, Mg, S, Cu and Ca:P ratio (P < .05). Cellulose and NDF were depressed in forage grab samples collected from FBCR- and limestone-amended pastures. The forage sampled the following spring was lower in hemicellulose, Zn, un and Ni; and higher in ash, Ca, S, the Ca: P ratio in the FBCR- and limestone-amended pastures. Mean serum mineral levels of steers were not affected by pasture treatment. The blood packed cell volume was higher in cattle grazing FBCR-amended pastures. Liver levels of Fe, H, Hi and Na were lower in cattle on pastures amended with FBCR or limestone. Bile levels of Mn were depressed in cattle grazing FBCR~ and limestone-amended pastures. The level of Cu in the liver and serum was at deficiency levels and was not detectable in bile, regardless of treatment. Higher kidney levels of Ca, Hg and P were recorded for steers grazing FBCR- and limestone-amended pastures. Hair Zn was higher in cattle grazing the FBCR- and limestone- treated pastures. Rib Cr and long bone Cd levels were lower in animals grazing the limestone- and FBCR-treated pastures. This study suggests that FBCR amendment enhances nutrient quality of forage and mineral status of animals at least as well as limestone application to acidic reclaimed mine pastures. / Ph. D. / incomplete_metadata