No description available.

No description available.

No description available.

Floating macrophyte pond systems, with the ability to produce nutrient enriched plants simultaneously with wastewater treatment, are a sustainable solution to contribute to environmental protection and safe nutrient recovery from domestic wastewater. However, to meet the requirements for reuse with high strength wastewater containing high levels of metal pollution generated in developing countries, an adequate combination of water hyacinth and duckweed ponds is proposed in order to take advantage of the best characteristics of each of these macrophyte ponds. This research focused on the advancing of the understanding of the effectiveness of treatment and resource recovery under the effect of changing operational parameters such as pH, light intensity, influent metal content and fluctuating pollutants loading rate on pond performance and recycling ability in order to fill the noticed gap of knowledge. Experiments conducted in water hyacinth ponds (WHP), under batch and tropical natural weather conditions, revealed that pH between 6.4 and 7.1, full sunlight and seven days hydraulic retention time were optimum for plant biomass production and pollutant removal in WHP. WHP was able to regulate pH when the initial pH values moved outside this interval with a drop in biomass production as a side effect. These ponds showed a first order kinetic for the removal of iron, zinc and copper from aqueous solution and their accumulation in plants biomass with a preferential sequence Fe > Zn > Cu. However the presence of metals in water hyacinth biomass led to the reduction in ponds performances and a risk of re-pollution of the effluent through the release of metals into water. A comparative study carried out over sixty-two weeks in a pilot scale combined water hyacinth and duckweed ponds (DWP) channel and waste stabilization ponds channel working under fluctuating loading rates showed different environmental conditions occurred these ponds. The fluctuating loading rate was also found to have a reduced effect on the combined WHP/DWP channel performance and effluent quality stability with the effluents meeting the entire reuse requirement at high hydraulic flow rate (retention time greater than 20 days). Fish was able to grow in the WHP/DWP channel. Results suggested some guidelines on WHP/DWP system design, operation and maintenance. The overall outcome of this research is a significant contribution to the development of integrated combined WHP/DWP technology for treatment of wastewater and resource recovery on site.

No description available.

Esta pesquisa foi desenvolvida na Estação de Tratamento de Esgoto de Cajati, onde o tratamento é realizado por lagoas de estabilização com sistema australiano. Em amostragens de variação nictemeral e sazonal, observou-se estratificação térmica nas duas lagoas, sendo que esta foi mais acentuada em abril. Em todos os períodos, a coluna de água esteve homogênea às 2h e 8h e estratificada às 14h e 20h. A estratificação térmica resultou na estratificação química (pH e oxigênio dissolvido), sendo que ambas as lagoas foram divididas em dois compartimentos: superior, com maiores temperaturas, pH e oxigênio dissolvido, e outro inferior, com comportamento contrário. A lagoa anaeróbia apresentou concentrações de oxigênio dissolvido de aproximadamente 10,0 mg/L, o que resulta em funcionamento inadequado também foi confirmado pelos resultados de clorofila nesta lagoa, que foram semelhantes aos da facultativa e atingiram até 3,5x\'10 POT.3\' \'mü\'g/L em abril e julho. Além disso, as concentrações de nutrientes e coliformes foram baixas no afluente bruto em relação às obtidas na literatura. Os valores de pH estiveram altos para lagoas de estabilização, com máxima de 12,17 em janeiro. Apenas em abril, o pH esteve menor (6,84-9,86), condizente com a literatura e adequado para fermentação anaeróbia. O menor pH e maiores temperaturas obtidos em abril resultaram em melhores eficiências de redução que nos outros períodos. As estimativas de vazão e carga orgânica revelaram que a ETE vem operando abaixo da carga prevista, o que pode influenciar na eficiência do sistema, pois este não terá tempo suficiente para formar comunidade microbiana estável. Não foi possível observar variabilidade vertical padrão das biomoléculas proteínas, carboidratos e lipídeos, nem ao longo do sistema. Observou-se heterogeneidade espacial e vertical entre as concentrações de nitrogênio e fósforo em todo sistema, onde alguns processos puderam ser identificados e estes foram influenciados por temperatura, pH e oxigênio dissolvido. Houve predomínio de cianobactéria (Synechocystis sp) na ETE Cajati, seguido de clorofícea (Chlorella kessleri). Em ambas as lagoas, o predomínio foi de Eubactéria com baixas concentrações de Arquéias. O efluente final esteve de acordo com os padrões de lançamento de efluentes estabelecidos na Resolução CONAMA 357/2005. / This research was developed in the Cajati wastewater treatment plant, where the treatment is carried through by stabilization ponds with australian system. In samplings of nictemeral and seasonal variation, thermal stratification in the two ponds was observed, and this was more accented in April. In all the periods, the water column was homogeneous at 2 a.m. and 8 a.m. and stratified at 2 p.m. and 8 p.m. Thermal stratification resulted in chemical stratification (pH and dissolved oxygen) and both the ponds had been divided into two compartments: superior, with higher temperatures, pH and dissolved oxygen, and another inferior, to the contrary behavior. The anaerobic pond presented concentrations of dissolved oxygen of approximately 10,0 mg/L that results in functioning inadequate confirmed by the results of chlorophyll in this pond. The anaerobic pond had been similar to the facultative one, which had reached 3,5 x \'10 POT.3\' \'mü\'g/L in April and July. Moreover, the concentrations of nutrients and coliforms had been low in the raw affluent in relation to those described in literature. The pH values had been high for stabilization ponds, with maximum of 12,17 in January. In April, pH was minor (6,84-9,86), according to literature and for anaerobic fermentation. The minor pH and greater temperature taken in April had resulted in better efficiencies of reduction that in the other periods. The estimates of outflow and organic load had disclosed that the plant is operating below the design load, which can influence the efficiency of the system, therefore it will not have enough time to form steady microbial community. Vertical and spatial variability was not observed for proteins, carbohydrates and lipids. Vertical and spatial heterogeneity was observed in nitrogen and phosphorus concentrations, where some processes could have been identified and these had been influenced by temperature, pH and dissolved oxygen. There were predominance of Cyanobacteria (Synechocystis sp) followed by Chlorophycea (Chlorella kessleri). In both ponds, there was predominance of Eubacteria with low concentrations of Archeae. The final effluent was in accordance with the established standards of discharge of effluent - Resolution CONAMA 357/2005.

Thesis--Auburn University, 2009. / Abstract. Includes bibliographic references (p.27-29).

Insights gained from metapopulation and metacommunity biology indicate that the connectivity of subpopulations and communities by species dispersal can profoundly impact population dynamics, community structure, and ecosystem attributes. Recent advancements in metacommunity theory further suggest that the rate of species dispersal among local communities can be important in altering local and regional species richness and ecosystem functioning. The role of species dispersal rates relative to patch-type heterogeneity and associated intrinsic community structuring mechanisms (competition, predation) in affecting diversity of multi-trophic communities, however, remains unknown. Here, I address the relative influence of regional and local processes in altering species richness and ecosystem functioning at multiple spatial scales in freshwater pond metacommunities. In a series of experiments, I employed pond mesocosm metacommunities to manipulate planktonic species dispersal rates and the incidence of top predators which differed in prey selectivity. The consequences of dispersal and predation to zooplankton species richness, trophic structure, ecosystem stability, and prey traits were evaluated. Generally, my findings support predictions from metacommunity models, and demonstrate that dispersal strongly affects community and ecosystem-level properties. In accord with dispersal-diversity theory, dispersal rate affected species richness and ecosystem stability at multiple spatial scales. The presence, but not the rate, of dispersal had strong effects on the partitioning of biomass amongst producers, grazers, and top predators. The relative influence of predation on local and metacommunity structure varied across experiments and largely depended upon predator identity and the degree of feeding specialization. The research presented herein is some of the first work to evaluate how species dispersal rates can affect dispersal-diversity relationships, diversity-stability relationships, trophic structure, and the distribution of prey traits in metacommunities. In addition to advancing ecological theory, the results have important implications for conservation as fragmented landscapes become increasingly prevalent, and local and regional biotas modified. Ultimately, it proves critical to identify drivers of local and regional species richness in order to maintain biotic integrity at the global scale. / text

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

Thesis (Ph. D.)--Lehigh University, 2004. / Includes bibliographical references and vita.