Dissolved organic matter (DOM) is one of the largest carbon reservoirs on this planet and is present in aquatic environments as a highly complex mixture of organic compounds. The Florida coastal Everglades (FCE) is one of the largest wetlands in the world. DOM in this system is an important biogeochemical component as most of the nitrogen (N) and phosphorous (P) are in organic forms. Achieving a better understanding of DOM dynamics in large coastal wetlands is critical, and a particularly important issue in the context of Everglades restoration. In this work, the environmental dynamics of surface water DOM on spatial and temporal scales was investigated. In addition, photo- and bio-reactivity of this DOM was determined, surface-to-groundwater exchange of DOM was investigated, and the size distribution of freshwater DOM in Everglades was assessed. The data show that DOM dynamics in this ecosystem are controlled by both hydrological and ecological drivers and are clearly different on spatial scales and variable seasonally. The DOM reactivity data, modeled with a multi-pool first order degradation kinetics model, found that fluorescent DOM in FCE is generally photo-reactive and bio-refractory. Yet the sequential degradation proved a “priming effect” of sunlight on the bacterial uptake and reworking of this subtropical wetland DOM. Interestingly, specific PARAFAC components were found to have different photo- and bio-degradation rates, suggesting a highly heterogeneous nature of fluorophores associated with the DOM. Surface-to-groundwater exchange of DOM was observed in different regions of the system, and compositional differences were associated with source and photo-reactivity. Lastly, the high degree of heterogeneity of DOM associated fluorophores suggested based on the degradation studies was confirmed through the EEM-PARAFAC analysis of DOM along a molecular size continuum, suggesting that the fluorescence characteristics of DOM are highly controlled by different size fractions and as such can exhibit significant differences in reactivity.

Made available in DSpace on 2015-09-25T12:23:37Z (GMT). No. of bitstreams: 1 Silvia Peres de Castro.pdf: 565210 bytes, checksum: bc1094dba26205895b29d51dc104b086 (MD5) Previous issue date: 2009-08-21 / The increasing global demand for energy and the diversity of manufactured products generates diverse residues that are frequently difficult to treat or degrade. The utilization of petroleum and its derivatives cause environmental damage via oil spillages and effluents generated by diverse processes such as car washes, petrol stations, public transport companies and even industrial kitchens. In this study a biological treatment was used as an alternative to treat these pollutants, which included two basic treatments to remove organic material: an aerobic process namely activated sludge and an anaerobic process, comprising a UASB reactor. The objective of this work was to treat by biological processes, a synthetic effluent derived from petroleum which characterized physico-chemically, as having oily characteristics, to evaluate comparatively the efficiency of organic matter removal via two different processes of biodegradation. The results obtained were submitted to statistical analysis by Box Plots and ANOVA at a significance level of 5%. The experimental work with bench scale activated sludge and UASB reactors was performed at The Experimental Station for the Biological Treatment of Sewage EXTRABES in Campina Grande - PB, using effluents synthesized in the laboratory to feed the reactors at elevated loads of organic matter containing lubricating oil and surfactants. The adopted treatments had significant organic carbon removal efficiencies; with values of 23.7 to 32% for aerobic treatment and 42 to 51% with anaerobic treatment thus demonstrating that UASB treatment was the more efficient process and could be adopted for the treatment of oily and surfactant-containing effluents. / A crescente demanda de energia necessária no mundo e a diversidade de produtos obtidos geram diversos resíduos difíceis de serem tratados. A utilização do petróleo e seus derivados causam danos ambientais, estes vêm desde os derramamentos de petróleo e seus componentes até mesmo de efluentes gerados nos mais diversos processos, como em lava-jatos, postos de combustíveis, empresas de transportes públicos e até mesmo em cozinhas industriais. Neste estudo utilizar-se-á tratamento biológico, como uma alternativa para o tratamento desses poluentes, dentre estes tratamentos tem se dois processos básicos para a remoção de material orgânico que foi estudado: os sistemas de lodos ativados e os reatores UASB. O objetivo desse trabalho foi tratar através de processos biológicos, efluentes sintéticos derivados do petróleo, bem como realizar a caracterização físico-química deste efluente oleoso, e determinar comparativamente a eficiência de remoção da matéria orgânica através de processos de biodegradação biológica. Os resultados obtidos foram submetidos a métodos estatísticos: estatística descritiva de distribuição (Box Plot) e análise de variância (ANOVA) fator único, com nível de significância de 5%. O trabalho experimental foi realizado na Estação Experimental de Tratamentos Biológicos de Esgotos Sanitários EXTRABES, localizado no bairro do Tambor na cidade de Campina Grande PB. Para a realização da pesquisa foram construídos, instalados e monitorados reatores de lodo ativado e UASB em escala de bancada. Os reatores foram alimentados com efluentes sintetizados no laboratório. Com esse procedimento buscou-se tratar biologicamente efluentes com elevada carga orgânica, contendo óleo lubrificante e substâncias surfactantes. Nos tratamentos adotados foi conseguido uma eficiência de remoção significativa, o tratamento aeróbio teve remoções de 23,7 a 32,1%, no tratamento anaeróbio a remoção da matéria orgânica foi de 51 e 42%, o que mostra que o tratamento anaeróbio utilizando o reator UASB teve uma melhor remoção da matéria orgânica, podendo esses tratamentos serem adotados para o tratamento de efluentes oleosos e surfactantes.