Thesis (M.S.)--University of Wyoming, 2008. / Title from PDF title page (viewed on August 4, 2009). Includes bibliographical references (p. 70-75).

Thesis (M.S.)--University of Tennessee, Knoxville, 2008. / Title from title page screen (viewed on Sept. 24, 2009). Thesis advisor: Liem Tran. Vita. Includes bibliographical references.

Thesis (M.Sc. Biological Sciences)--University of Waikato, 2008. / Title from PDF cover (viewed March 10, 2009) Includes bibliographical references (p. 62-72)

Thesis (Ph. D.)--University of Wisconsin--Madison, 1974. / Typescript. Vita. Description based on print version record. Includes bibliographical references (leaves 229-237).

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: William J. Ullman, Dept. of Marine and Earth Studies. Includes bibliographical references.

A critical review of the mechanisms of present water treatment systems including, chlorination, coagulation, filtration, granular and powdered activated carbon adsorption, ozonation and ultraviolet radiation for the removal of herbicides is presented. Rapid selective and sensitive HPLC methods were developed and rigorously validated for the analysis of the selected herbicides. Analysis of atrazine was made using Cl8 cartridges. For raw water containing interferences, extraction of the compound was made on SCX cartridges, followed by solvent exchange on C18 cartridges. A quantitative recovery of virtually 100% of the compound was achieved using C18. While the double cartridge extraction of the compound gave a recovery of about 89%. Previously developed methods for 2,4-D and MCPA were rigorously validated for the extraction and analysis of 2,4-D and MCPA. A quantitative recovery of usually greater than 90% was achieved for both compounds using Cl8 cartridges. For the extraction of paraquat different extraction systems including, reversed phase on C8 and C18, ion-paired reversed phase on C18, and cation exchange on SCX, CBA, and CN were investigated. A quantitative recovery, usually greater than 90%, of the compound was obtained using CN and CBA cartridges. The methods were then successfully used for the evaluation of the removal efficiency and establishment of mechanisms of removal of herbicides by biological filters at bench and pilot scale. Four herbicides belonging to three broad chemical categories were studied. The data presented in this study demonstrated that biological filters are very efficient in removing certain classes of herbicides. 2,4-D and MCPA were consistently removed to below a detection limit of 0.1 mug/1 for an influent concentration of 3-11 mug/1. Process variables such as flow rate, bed depth and contact time were investigated for the efficient removal of these herbicides. Seasonal variations in performance were observed and possible explanations proposed. A series of experiments was undertaken to establish .mechanisms of removal. Quantitative recovery of the herbicides from the river water proved that the processes in the filter bed as opposed to the processes in the water were responsible for removal of the herbicides. It was clear from the investigation of the adsorption of the herbicides both on the sand and organic and inorganic dirt that adsorption on these surfaces was not the main reason for removal. Filter maturation experiment showed that the presence of microorganisms in the bed is a precondition for the removal of herbicides. A depth experiment for the removal of 2,4-D showed that superficial efficient zone of removal imitates the distribution of microbial density. This evidence confirms the significance of microorganisms for the removal of herbicides by the filter bed. The ultimate proof of the biodegradation of 2,4-D by microorganisms in the filter bed was the identification of the biodegradation product 2-chlorophenol as predicted by the metabolic pathways of the compound. Filter design modifications using activated carbon were made to accommodate the removal of 'non-biodegradable' herbicides. A sandwich sand / GAC / sand filter was investigated. Filter efficiency for this arrangement was determined and short-comings were identified and a possible solution in the form of a double GAC sandwich is suggested.

Thesis (M.E.S.)--The Evergreen State College, 2007. / Title from title screen (viewed 3/27/2008). Includes bibliographical references (leaves 51-52).

Thesis (M.Sc. Earth and Ocean Sciences)--University of Waikato, 2007. / Includes bibliographical references (leaves 139-148) Also available via the World Wide Web.

Thesis (M.S.)--University of Nevada, Reno, 2008. / "December, 2008." Includes bibliographical references (leaves 79-81). Online version available on the World Wide Web.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / This study consisted of two experiments. The first objective was to demonstrate the technical feasibility of separate BFT tank technology in juvenile cultivation of Nile tilapia, for monitoring quality variables of water and productive performance. The fish were fed different combinations of artificial food (balanced diet) and natural food (bioflocs biomass). As the supply of food decreased the tanks increased the biomass supply bioflocs. Bioflocs biomass was produced in an external tank 500 L, separately from the cultivation system (separate tank BFT). You can reduce the regular feeding rates of juvenile Nile tilapia, with artificial diets, 25 %, without losses, if bioflocs to provide wet grown animals, as a food supplement, in equal proportion. The second objective was determine the effects of the provision of dried bioflocs biomass to Nile tilapia juveniles, stocked in experimental rearing tanks for 8 weeks, upon selected variables of water quality, growth performance and effluents quality. Fish was fed with different combinations of artificial diets and bioflocs biomass, in the wet form (in natura) or dried. As the supply of artificial diet was decreased, the provision of bioflocs biomass was increased in the same proportion. The bioflocs biomass was produced in two extra 500-L tanks. The growth performance of fish that were partially fed with dried bioflocs biomass has remained below what was observed in the tanks supplied with the wet bioflocs biomass. Due to the lacking of positive results, there is not any rationale to dry the bacterial bioflocs aiming at the delivery of it as a dried biomass to the cultured fish. / O presente estudo foi constituÃdo por dois experimentos completos e consecutivos. No primeiro, objetivou-se demonstrar a viabilidade tÃcnica da tecnologia do tanque BFT (c/bioflocos) avulso no cultivo de juvenis de tilÃpia do Nilo, pelo monitoramento de variÃveis de qualidade de Ãgua e de desempenho produtivo. Os peixes foram alimentados com diferentes combinaÃÃes de alimento artificial (raÃÃo balanceada) e de alimento natural (biomassa de bioflocos). à medida que diminuÃa o aporte de raÃÃo aos tanques, aumentava o fornecimento de biomassa de bioflocos. A biomassa de bioflocos foi produzida em um tanque externo de 500 L, em separado do sistema de cultivo (tanque BFT avulso). Os tanques de cultivo que receberam aplicaÃÃes diÃrias de bioflocos apresentaram concentraÃÃes de nitrito na Ãgua significativamente menores do que as observadas nos tanques nos quais a Ãnica fonte de alimentaÃÃo dos peixes foi a raÃÃo comercial. Concluiu-se que à possÃvel reduzir as taxas regulares de arraÃoamento de juvenis de tilÃpia do Nilo, com raÃÃes artificiais, em 25%, sem prejuÃzo zootÃcnico, caso se forneÃa bioflocos Ãmidos aos animais cultivados, como suplemento alimentar, em igual proporÃÃo. O segundo experimento teve como objetivo determinar os efeitos do fornecimento de biomassa seca de bioflocos a juvenis de tilÃpia do Nilo, mantidos em tanques experimentais de cultivo por oito semanas, sobre variÃveis selecionadas de qualidade de Ãgua, desempenho zootÃcnico e qualidade de efluentes. Os peixes foram alimentados com diferentes combinaÃÃes de raÃÃo balanceada e biomassa de bioflocos, na forma Ãmida (in natura) ou seca. à medida o aporte de raÃÃo aos tanques foi menor, o fornecimento de biomassa de bioflocos foi proporcionalmente maior. A biomassa de bioflocos foi produzida em dois tanques avulsos de 500 L. O desempenho zootÃcnico dos peixes nos tanques que receberam a suplementaÃÃo de biomassa seca de bioflocos ficou abaixo do observado nos tanques com biomassa Ãmida. Pela ausÃncia de resultados positivos, concluiu-se que nÃo hà justificativa tÃcnica para a secagem dos bioflocos bacterianos com o objetivo de fornecer a biomassa seca aos peixes cultivados