Thesis (MSc)--University of Stellenbosch, 2007. / Bibliography. Also available via the Internet.

Thesis (M.Eng.Sc.)--University of Western Australia, 2007.

In Östersund there are a few stormwater ponds and oil separation units   connected to the stormwater network, but mostly there is no systems for   filtration of stormwater before it is released into a nearby lake which acts   as Östersund’s source of drinking water. In the Industrial area in Lugnvik there   is an oil separation unit connected to the stormwater network but no other   means of filtration. This study will be conducted as a case study for the   industrial part of catchment area 6 of the municipality of Östersund’s   stormwater system, where this area acts as an example to apply the   dimensioning methods on. Aside from grease (O/G) residues that might be   removed by the oil separation unit, pollutants such as heavy metals,   nutrients and suspended solids (SS) are present in the area. Which will make   its way to the lake trough the existing stormwater system. One way to   filtrate stormwater is to construct an open vegetated stormwater system,   where the water is filtered as it passes through the vegetation and/or   infiltrates to the ground and/or trough sedimentation. The purpose of this study is to evaluate some commonly used for Sweden   relevant methods for dimensioning open stormwater systems. The evaluation is   to see if the methods result in a system size that would give a satisfactory   removal of heavy metals, or if the methods is not suitable to use for   dimensioning a vegetated stormwater system if the purpose is to remove heavy   metals. The study should give answers to if currently and commonly used   methods for dimensioning open stormwater systems is suitable to use for   dimensioning of open vegetated stormwater systems by relating the results to   real examples when the purpose of the open stormwater system is to reduce   heavy metal concentrations. Further, the study shall help to identify   important factors that regulates the removal rate of heavy metals as well as   determine what particle size that should be targeted to reach a satisfactory   removal rate of heavy metals. A conclusion if   the dimensioning methods is suitable to use or not is difficult to draw as   the size of the system depends on what values that are used to calculate the   stormwater flow. Therefore, there is a large variation in the resulting   system size. To add to this uncertainty, the projection that is based on   measurements on real systems is not accurate as this only use the size of the   system in relation to the size of the impervious catchment area as a factor   for heavy metal removal. In reality this is not the case, which is indicated   by the R2-values of these projections. Other factors that in this study is   confirmed to have an impact on the removal rate is particle size, surface   load/flow, and in the case of vegetated filter strips the slope of the   filter. The particle size that should be targeted is likely within the range   of 45-65 μm. / <p>20181116</p>

There are an estimated 2.6 million small water bodies in the contiguous United States. These features are mostly manmade representing a major source of land use change. Compared to larger reservoirs, the impacts of small water bodies on watershed hydrology are not well understood and were the main focus of this research. Using three sets of streamflow parameters, the hydrological impacts of small water bodies were evaluated in 29 watersheds of the Midwest. This relationship was evaluated with four other geophysical watershed traits, and variations in the relationships were examined across three regions of the study area. Of the six geophysical watershed traits examined, results indicate that a watershed's percent area of small water bodies was the strongest predictor of high flow coefficients. This relationship was positive and statistically significant with a distinct regional relationship in Eastern Iowa. Time of concentration and watershed area were significant predictors of low flow coefficients. Time of concentration was also a significant predictor of the rainfall-runoff ratios. The distinct positive relationship between small water bodies and high flow coefficients, and insignificant relationships with runoff ratios are unexpected and intriguing findings, representing possible opportunities for future investigations.

Orientador: Liliane Lazzari Albertin / Resumo: A presença de fármacos e parabenos em esgoto doméstico é uma questão de grande preocupação devido seus efeitos negativos em ecossistemas e na saúde humana. Neste sentido a fitoremediação surge como sendo uma alternativa vantajosa de remoção dos micropoluentes, o baixo custo de implantação e manutenção é um fator atrativo. O presente estudo visa avaliar a capacidade de duas macrófitas aquáticas (Landoltia punctata e Lemna minor.), para remoção de fármacos (Diclofenaco e Naproxeno) e parabenos (Metil e Propil parabeno) do esgoto doméstico. Foram utilizados dois tanques de 3000 mil litros, sendo Tanque A composto por Landoltia punctata e Tanque B , Lemna minor, foram coletadas amostras a cada três dias durante 21 dias nos períodos diurno e vespertino. Os resultados de remoção para os fármacos do Tanque B, em média 0,63 g/L( remoção de 96.70% ) para diclofenaco e 30,60g/L para naproxeno (remoção de 49,29%) respectivamente, enquanto o Tanque A atingiu 3,42g/L para diclofenaco e (remoção de 80,4%) 34,47g/L para naproxeno (remoção de 36,85%). Os resultados para remoções de metilparabeno foi para tanque A (diurno e vespertino) foram de 14,36 e 14,78g/l, (remoção de 90,87% e 90,60%), enquanto o tanque B foi de 16,86 g/L para período diurno ( eficiência de 90,61%), 17,22g/L, e a sua (eficiência de 89,05%) durante o período vespertino. Para propil parabeno houve uma maior remoção para tanque B de 16,18 g/L para (PrPP), ( eficiência de 89,35%), enquanto que para o período ves... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Dentre as diversas etapas para a transformaÃÃo de microalgas em biodiesel, os processos de separaÃÃo e a ruptura celular dessa biomassa sÃo particularmente importantes, uma vez que as tecnologias disponÃveis para este fim apresentam elevados custos, comprometendo a viabilidade do aproveitamento energÃtico. Este trabalho teve como objetivo geral estudar os mecanismos envolvidos na separaÃÃo e ruptura simultÃneas de biomassa algal pelo uso da tecnologia de eletroflotaÃÃo por corrente alternada (EFCA), com objetivo principal de extrair o conteÃdo lipÃdico da biomassa algal, assim como verificar o potencial da tecnologia na remoÃÃo de nutrientes de efluentes de lagoas de estabilizaÃÃo. Foram realizados ensaios de coagulaÃÃo/floculaÃÃo em jar test com coagulantes sintÃticos (FeCl3 e Al2(SO4)3) e orgÃnicos (Tanfloc SG e SL) com o objetivo de avaliar a decantaÃÃo quimicamente assistida na separaÃÃo de biomassa algal. Foi desenvolvido um reator de EFCA para operar em batelada, utilizando-se eletrodos nÃo consumÃveis e baixa potÃncia elÃtrica. Foi avaliado o seu potencial de separaÃÃo com e sem o auxÃlio dos mesmos coagulantes utilizados nos testes de jarro e, em seguida, buscou-se variar as frequÃncias de operaÃÃo do conjunto de eletrodos com o objetivo de verificar a condiÃÃo Ãtima para separaÃÃo e rompimento celular das microalgas. Foi tambÃm avaliada a capacidade desta metodologia na remoÃÃo de nutrientes presentes nos efluentes e elucidar os mecanismos envolvidos. Foi possÃvel a remoÃÃo de biomassa algal tanto por meio da decantaÃÃo quimicamente assistida quanto pela EFCA, sendo que a segunda à mais atrativa nÃo somente pelas eficiÃncias de remoÃÃo de turbidez e clorofila-a encontradas, como tambÃm pela nÃo necessidade aparente de utilizaÃÃo de coagulantes, o que traz economia ao processo e facilita a reutilizaÃÃo da biomassa algal. A EFCA mostrou-se ainda capaz de promover com eficiÃncia o rompimento celular das microalgas e fazer com que os lipÃdeos liberados se aderissem à biomassa algal separada pelo processo. Foi possÃvel alcanÃar um rendimento lipÃdico de atà 14% em peso de massa seca, mesmo os estudos tendo sido realizados com uma matriz diversa de microalgas proveniente das lagoas de estabilizaÃÃo. O estudo dos mecanismos envolvidos revelou a boa capacidade do sistema em gerar gÃs hidrogÃnio, o qual alÃm de ajudar na separaÃÃo das microalgal pode tornar futuramente o processo energeticamente sustentÃvel. AlÃm disso, foi verificada a geraÃÃo de espÃcies oxidantes que ajudam tanto o processo de separaÃÃo quanto possivelmente de ruptura celular. O efeito de diferentes frequÃncias de vibraÃÃo nos rendimentos lipÃdicos encontrados nÃo foi aparente. Buscou-se ainda a elucidaÃÃo dos mecanismos de remoÃÃo de fÃsforo total, o que provavelmente se deu pela formaÃÃo de ferro durante o processo, cujos valores ficaram na ordem de 2,5 mg/L depois de 70 minutos de batelada. Jà para a remoÃÃo de amÃnia, possivelmente o mecanismo foi de oxidaÃÃo indireta da amÃnia atravÃs do excesso de Ãcido hipocloroso como a forma predominante de conversÃo da mesma em nitrogÃnio gasoso, o qual ajuda no processo de separaÃÃo. A utilizaÃÃo de microalgas diretamente de lagoas de estabilizaÃÃo mostrou-se uma potencial alternativa aos processos de obtenÃÃo de biomassa tradicionalmente utilizados (fotobiorreator e lagoas do tipo raceway), sendo que a tecnologia proposta se mostrou atrativa para todos processos que demandem separaÃÃo algal. / Among the various steps for microalgae transformation in biodiesel, the harvesting and cell disruption processes are particularly important, since technologies available for this purpose have usually high costs, undermining the energy recovery viability. This work studied the mechanisms involved in the simultaneous harvesting and cell disruption of microalgae using electroflotation by alternating current (EFCA), as well as to investigate the system capacity on nutrients removal from waste stabilization ponds effluents. Coagulation/flocculation tests were performed using synthetic (FeCl3 e Al2(SO4)3) and organic (Tanfloc SG e SL) coagulants to evaluate the chemically assisted sedimentation of the algal biomass. The EFCA reactor was designed to operate in batch, using non-consumable electrodes and low electrical power, and evaluated the harvesting potential in the presence and absence of coagulants. After this, experiments were performed varying the electrode frequency to verify the optima condition for simultaneous harvesting and cell disruption of microalgae. The system capacity in terms of nutrients removal was also investigated as well as the mechanisms involved. It was possible to remove algae biomass both using chemically assisted sedimentation and EFCA. However, the electrolytic technology is more attractive, not only for the turbidity and chlorophyll-a efficiencies founded, but also because there is no apparent need of coagulants, which makes the process cheaper and facilitates the microalgae biomass reuse. The EFCA was even able to promote the cell disruption of microalgae and the liberated lipids were able to attach to the algal biomass separated by the process. A lipid yield of 14 % in terms of dry matter was found, even when a complex matrix from waste stabilization ponds was used. The study of the mechanisms involved in EFCA revealed the good system ability to generate hydrogen gas, which contributes to microalgae harvesting and can make the process even more sustainable under an energetic perspective. Furthermore, the generation of oxidant species was found which helps the harvesting and cell disruption process. The effect of different vibration frequencies in the lipid yield was not apparent. We sought to elucidate the mechanisms involved on total phosphorus removal, and probably the removal was due to iron formation in the process, in which the concentrations were close to 2.5 mg/L after 70 minutes batch time. In terms of ammonia removal, possibly the mechanism was an indirect oxidation by excess of hypochlorous acid to form nitrogen gas, which helps the separation process. The use of microalgae from stabilization ponds showed a potential alternative for the processes traditionally used nowadays for microalgae production (photobioreactor and raceway ponds), and showed to be attractive to all processes that demand microalgae harvesting.

Dissertação(mestrado)-Universidade Federal do Rio Grande, Programa de Pós–Graduação em Aqüicultura, Instituto de Oceanografia, 2008. / Submitted by Cristiane Silva (cristiane_gomides@hotmail.com) on 2012-08-08T22:52:24Z No. of bitstreams: 1 Graziele.pdf: 800609 bytes, checksum: a78917e56fee21a2cd42824b8e828291 (MD5) / Approved for entry into archive by Bruna Vieira(bruninha_vieira@ibest.com.br) on 2012-08-21T17:14:53Z (GMT) No. of bitstreams: 1 Graziele.pdf: 800609 bytes, checksum: a78917e56fee21a2cd42824b8e828291 (MD5) / Made available in DSpace on 2012-08-21T17:14:53Z (GMT). No. of bitstreams: 1 Graziele.pdf: 800609 bytes, checksum: a78917e56fee21a2cd42824b8e828291 (MD5) Previous issue date: 2008 / As fazendas de cultivo de camarões com altas densidades, liberam efluentes com altas cargas de nutrientes, provocando a degradação da qualidade da água. Isto gera preocupação a respeito do lançamento de efluentes dos cultivos. Em vista disto, este trabalho teve como objetivo avaliar a eficiência de um sistema integrado de bacia de sedimentação e biofilme na remoção de nutrientes. O estudo foi realizado em ambiente aberto, durante 45 dias. Foram utilizados três tratamentos: a) tratamento TC, sem substrato vertical; b) tratamento T50, superfície interna das caixas aumentada em 50% e c) tratamento T100, superfície interna das caixas aumentada em 100%. As caixas foram abastecidas com o efluente de um cultivo de camarão. Diariamente foram medidos o pH, a salinidade, o oxigênio dissolvido (OD) e a temperatura. Durante os primeiros 15 dias as coletas foram feitas a cada 5 dias, após esse período as coletas de água foram a cada 2 dias, e de biofilme diariamente. As análises de amônia foram feitas em todos os dias de amostragem. As análises de nitrito, nitrato e fosfato, foram feitas de todas as coletas até o 15º dia, e após esse período a cada 6 dias. Do biofilme, a matéria seca foi determinada de todos os dias coletados. A clorofila a analisada a cada 5 dias. E a estimativa de ciliados e flagelados nos dias 5, 10, 15 e 20. Os resultados mostraram que os tratamentos TC e T50 reduziram mais de 80% da amônia e fosfato em 10 dias. O tratamento T100 nos primeiros dias apresentou os menores valores de OD, pH e clorofila a, provocando um pico nas concentrações de amônia e fosfato, retardando a remoção destes nutrientes. Para todos os tratamentos após o 15º dia a concentração de fosfato sofreu uma elevação que se manteve até o final do experimento. Concluindo que ao dobrar a área disponível para fixação de biofilme há uma dificuldade de circulação nos tanques, e um aumento da respiração microbiana, tornando o sistema menos eficiente. Já a bacia de sedimentação sem biofilme, ou com 50% de acréscimo de substrato, ambos são eficientes. Portanto, o efluente deve permanecer na bacia de sedimentação por um tempo mínimo de 10 dias, mas não ultrapassando 15 dias, para não haver elevação nos níveis de fosfato. / The shrimp farms with high densities, release effluents with high loads of nutrients, causing water quality degradation. This creates concern about the release of effluents of cultures. In this work, we aimed to assess the efficiency of an integrated system of settling ponds and biofilm in the nutrients removal. The study was conducted in an open environment, for 45 days. We used three treatments: a) treatment TC, without vertical substrate b) treatment T50, inner surface of the tanks increased by 50% and c) treatment T100, inner surface of the tanks increased by 100%. The tanks were supplied with the effluent of a shrimp culture. Daily were measured pH, salinity, dissolved oxygen (OD) and temperature. During the first 15 days the collections were made every 5 days, after that period the collection of water were every 2 days, and biofilm daily. Analyzes of ammonium were performed on all days of sampling. Analyzes of nitrite, nitrate and phosphate, were made of all collections until the 15 th day, and after this period every 6 days. Of the biofilm, the dry matter was determined in every day collected. The chlorophyll-a reviewed every 5 days. And the estimate of ciliates and flagellates on days 5, 10, 15 and 20. The results showed that the treatments TC and T50 reduced more than 80% of ammonium and phosphate in 10 days. The treatment T100 in the first few days showed the lowest values of OD, pH and chlorophyll-a, causing a peak in the concentrations of ammonium and phosphate, delaying the removal of these nutrients. For all treatments after the 15 th day the concentration of phosphate has an elevation which remained until the end of the experiment. Concluding that to double the area available for setting biofilm there is a difficulty in circulation in tanks, and an increase in microbial respiration, making the system less efficient. Already the settlement ponds without biofilm, or with 50% increase in substrate, both are effective. Therefore, the effluent must remain in the basin settling ponds for a minimum time of 10 days but not exceeding 15 days, for no elevation in the levels of phosphate.

As lagoas de estabilização representam um dos métodos mais simples utilizados para tratamento de esgoto sanitário. Grande parte da matéria orgânica presente no esgoto sanitário é constituída por proteínas, a qual torna-se fator limitante aos processos biológicos de tratamento de águas residuárias em que se encontram presentes. O objetivo deste trabalho foi avaliar e comparar métodos colorimétricos para determinação de proteínas, definindo qual é o mais apropriado para esse tipo de ambiente. Os métodos colorimétricos utilizados foram o de Lowry, de Bradford, do Biureto e do Ácido Bicinconínico. As proteínas padrões utilizadas foram soroalbumina, caseína e ovoalbumina. O método de Bradford apresentou várias desvantagens. Biureto I e III e proteína bruta medida a partir do Nitrogênio Total Kjeldah (NTK) apresentaram valores altos devido não medir somente proteínas. A quantidade de proteínas na amostra não foi suficiente para que ocorresse reação no método Biureto II. O método do Ácido Bicinconínico não reagiu com caseína e o custo do reagente é alto. Portanto, o método apropriado para esse tipo de amostra foi o Lowry que apresentou maior reprodutividade e sensitividade. Para comprovar esse resultado, uma análise de adição de padrão à amostra foi realizada para verificar se haviam substâncias interferentes, cujo resultado foi negativo / Stabilization ponds represent a simple method to treat sanitary sewage. A large part of the organic matter present in sanitary sewage consists of proteins, which become a limiting factor for the wastewater treatment in biological processes. The goal of this work was to evaluate and to compare colorimetric methods for protein determination, defining which is the more appropriate for this environment. The colorimetric methods used were the Folin-phenol, Bradford, Biuret and Bicinconinic Acid methods. The protein standards used were serum albumin bovin, casein and ovalbumin. The Bradford method introduced several disadvantages. Biuret I and III and brute protein introduced high values due don't measure only proteins. The proteins quantity in the sample wasn't enough so that it had occurred reaction in the Biuret II method. The method of Bicinconinic Acid didn't react with casein and the reagent cost is high. Therefore, the method appropriated for this sample was the Lowry that introduced larger reprodutivity and sensitivity. To prove this result, a standard addition analysis was performed to verify if there were interfering substances, whose result was negative

Hydrologic and hydraulic modeling are used to assess watershed function at different spatial and temporal scales. Many tools have been developed to make these types of models more accessible to use and model results easier to interpret. One tool that makes hydrologic models more accessible in a geographic information system (GIS) is the Automated Geospatial Watershed Assessment tool (AGWA); the GIS enables the development of spatially variable model inputs and model results for a variety of applications. Two major applications of AGWA are for rangeland watershed assessments and post-wildfire rapid watershed assessments. Each of these applications have primarily utilized the Kinematic Runoff and Erosion model (KINEROS2) which is accessible in AGWA. Two new tools were developed which work within the existing AGWA/KINEROS2 framework in ArcGIS to enhance rangeland and post-wildfire watershed assessments. The Storage Characterization Tool, was developed to work with high-resolution topographic data to characterize existing stock ponds so these features can easily be incorporated into AGWA/KINEROS2 for rangeland hydrologic analysis. The second tool simulates reach scale flood inundation (the Inundation Tool) utilizing AGWA/KINEROS2 outputs and local channel properties for Hydrologic Engineering Center (HEC-2) hydraulic calculations to compute flood inundation in post-wildfire environments. Both tools have been validated using multiple datasets and desired applications were outlined so that the tools are properly used.

Stormwater ponds (SWPs) are becoming increasingly important due to the negative impacts on flood mitigation and water quality control that results from rapid urbanization. These ponds are not only designed to control the discharge of large precipitation and snow melt events, but also to mitigate the water quality of the retained stormwater. Consequently, improper design and maintenance may lead to hypoxic conditions in SWPs, which result in poor water quality and generation of noxious gases. Riverside South Stormwater Pond II (RSPII) in Ottawa periodically experiences low dissolved oxygen (DO) concentrations and subsequently hypoxic conditions at depth in the pond, especially during summer days with less precipitation and winter ice covered periods. Hydrogen sulfide gas (H2S) has been generated and released into the ambient atmosphere during these periods of lesser water quality. Hence, there is a need to understand how DO spatial distribution and seasonal change trigger and affect H2S production. The conventional shallow design criteria of SWPs likely cause these systems to be susceptible to wind conditions. Very few research has demonstrated the correlation between wind-driven hydraulic performance and detained stormwater quality. Hence an understanding of pond-scale mixing generated by wind-induced flow and the subsequent correlation to DO concentrations and stratification in SWPs are important to understanding the water quality and performance of these systems, especially in a wind-induced flow dominated SWPs. The overall research objective is to develop a comprehensive understanding of hypoxic conditions of SWPs and to investigate the impact of wind induced hydraulics on DO seasonal characteristics and the subsequent production of H2S. RSPII was shown to experience lower DO and longer hypoxic conditions than an adjacent reference pond (RSPI) at both non-ice covered and ice covered months. In addition, hypoxia was shown to be initiated at the outlet of RSPII where the depth of the pond was a maximum. Interestingly, chlorophyll-α blooms were observed during ice covered conditions in the study, with synurids, tabellaria, and asterionella being identified as the dominant species. A bottom-mount acoustic Doppler current profiler (aDcp) was used to collect small wind-generated currents in RSPII. The three-dimensional current and DO model produced by MIKE 3 (DHI software) suggests a conclusive result of pond scale mixing produced by wind-driven flow as well as countercurrents near the bed opposite to wind direction. A wind dominated circulation was shown to be generated even with moderate wind speed, and with a higher wind condition pond-scale complete DO mixing was created. The MIKE 3 simulation further provided a comprehensive understanding of the correlation between wind-induced hydraulics and DO concentrations distribution in a shallow stormwater pond. Therefore, this research demonstrates that wind is an essential hydraulic driver in shallow ponds, which also likely affects water quality by initiating pond mixing.