L’imperméabilisation des surfaces et l’augmentation des débits de pointe sont liés au développement croissant des environnements urbains. Avec cette croissance urbaine, les processus de ruissellement sont largement affectés et représentent un secteur dans lequel des actions doivent être entreprises afin d’assurer à la fois le développement économique et la protection de l’environnement et des ressources en eau. Le ruissellement est fréquemment associé à des pollutions diffuses (Non Point Source) qui ne sont généralement pas prises en compte dans les dispositifs classiques de régulation hydraulique. L’objectif de cette recherche était d’évaluer les performance de dispositifs de filtration sur les micro particules polluantes diffuses issues des chaussées routières et des déversoirs d’orages des réseaux d’assainissement unitaires (Combined Sewer Overflows – CSOs). Le protocole expérimental implique de mesurer, dans un premier temps, la taille et les caractéristiques des particules polluantes diffuses et ensuite, de réaliser une procédure identique à la sortie des installations de filtration et de traitement. Les modifications dans la distribution de la taille des particules et de leurs caractéristiques sont alors analysées. Les quatre principaux dispositifs de filtration disponibles - Expanded Polypropylene (EPP), Expanded polystyrene (EPS), Perlite pour les particules flottantes et Zeolite pour les non flottantes – ont été implanté sur un équipement de test et les résultats comparés. Une modélisation 3D (CFD) a été réalisée afin d’optimiser la conception de la disposition de filtration. / The impermeable area and the peak discharge volume have been consistently increasing due to widening of city development and renewal. Thus, distortion of water cycle has been serious problem compared to the past. When it comes to NPS pollution, lack of information on the load and characteristics of pollutants led to the insufficient reduction measures. The purpose of this study is to investigate the effectiveness of filters to control micro particles from non-point sources, especially from road runoff and Combined Sewer Overflows (CSOs). The study first examined the particle size and characteristics of NPS pollutants, and then analyzed the head loss, treatment efficiency and changes in particle size distribution before and after the treatment using device type facilities. The four most commonly used filters - Expanded Polypropylene (EPP), Expanded polystyrene (EPS), and Perlite as floatability filtering materials, and Zeolite as non-floatability - were compared. The upward-type filtering equipment was manufactured for the lab experiment, and CFD modeling was conducted to identify optimized design parameters. The results showed that the ratio of micro particles(＜100 ㎛), to which the filtering process can be applied, was highest in samples from the road runoff, followed by one from the bridge, and from the parking lot. The results using road runoff displayed that EPP was most efficient with ratio of 89% to treat SS and COD.

An emission inventory tool for estimating SO2, NO2, and PM10 emissions from brick clamp kiln sites was developed from investigations performed on three representative South African clamp kiln sites in order to facilitate application for Atmospheric Emission Licenses (AELs) from these sources. The tool utilizes readily available site-specific parameters to generate emission factors for significant activities that emit the aforementioned pollutants. PM10 emission factors for significant processes were developed using empirical expressions from the Compilation of Air Pollutant Emission Factors (AP-42) documents. SO2 emission factor for clamp kiln firing was obtained from “reverse-modelling”, a technique that integrates ambient monitoring and dispersion modelling (using Atmospheric Dispersion Modelling System software) to “standardize” actual emission rate from an assumed rate of 1 g/s. The use of multiple point sources proved to improve the simulation of the buoyancy-induced plume rise; therefore, a “bi-point” source configuration was adopted for the kiln. The “reverse-modelling” technique and “bi-point” source configuration produced SO2 emission rates differing from -9 % to +22 % from mass balance results, indicating that the “reverse-modelling” calculations provide reliable emission estimates for SO2. An NO2 emission factor could not be obtained from the “reverse-modelling” technique due to experimental errors and the significant effect of NO2 emissions from other onsite air emission sources such as internal combustion engines. The NO2 emission factor was obtained from previous comprehensive study on a similar clamp kiln site. The emission factors obtained from this study were utilized in developing an “emission inventory tool” which is utilized by clay brick manufacturers in quantifying air emissions from their sites. Emissions quantification is a requirement for brick manufacturers to obtain an AEL which is regulated under South African environmental laws. It is suggested that the technique used here for SO2 emission confirmation could be used to estimate emissions from a volume or area source where combustion occurs and where knowledge of the source parameters is limited. / Dissertation (MSc)--University of Pretoria, 2013. / gm2014 / Chemical Engineering / unrestricted

Using benthic macroinvertebrates to measure stream health has been widely used and accepted around the world. Macroinvertebrates are resident monitors of chronic impairment in a stream since they are relatively sessile and most commonly respond to disturbance by drift but can recolonize a restored stream reach very quickly. This study tested the effectiveness of macroinvertebrate metrics developed through the Rapid Bioassessment Protocol (RBP) to detect changes in stream integrity as the result of placement of a best management practice (BMP), installed on a tributary of Roaring Branch, located in Columbus, Georgia. The BMP was designed to attenuate flow to reduce sediment suspension and downstream deposition. A sampling protocol derived from the Georgia Ecoregions Project was implemented to evaluate the macroinvertebrate community, located downstream of the BMP, and downstream of the confluence with Roaring Branch, both before and after the BMP installation. The resulting metrics were compared to a reference condition described for subecoregion 65c, sandhills-lower piedmont. A dramatic improvement or increase of macroinvertebrate populations suggests an improvement in water quality (via reduction in fine sediment deposition) due to improved physical habitat conditions for indicators (Trichoptera) of healthier streams. The results of this study suggests further restoration activities should continue and that re-evaluation of the sampling protocol should take into account a larger subsample size of benthic macroinvertebrates than currently recommended by the RBP.

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A road can be considered as a noise source based on its traffic density. Intuition says, a road, with closely spaced vehicles, can be classified as a line source and for sparsely spaced vehicles, a collection of point sources. This study deals with the classification of a stretch of highway into either a line source or a collection of point sources based on the sound pressure measured by 7 microphones placed at certain distances from the highway and on the law of attenuation applicable. The results indicate a strong dependence of source classification with the traffic density. / En väg kan betraktas som en bullerkälla baserat på dess trafikintensitet. Intuitivt bör en väg med hög trafikintensitet klassificeras som en linjekälla och för få fordon en samling punktkällor. Denna studie handlar om klassificeringen av en motorvägssträcka till antingen en linjekälla eller en samling punktkällor baserat på ljudtrycket uppmätt med sju mikrofoner placerade på varierande avstånd från motorvägen. Resultaten visar att källklassificeringen är beroende av trafiktätheten och av avståndet till vägen.

The simple accumulation-based network identification method (ANIM) in a raster Geographic Information System (GIS) posed by O'Callaghan and Mark (1984) has been criticized for producing a spatially uniform drainage density (Tarboton 2002) at the watershed scale. This criticism casts doubt on the use of ANIMs for deriving properties such as overland flow length for nonpoint source pollution models, without calibrating the accumulation threshold value. However, the basic assumption that underlies ANIMs is that convergent topography will yield a more rapid accumulation of cells, and thus, more extensive flow networks, with divergent, or planar terrain yielding sparser networks. Previous studies have focused on networks that are coarser than the hill-slope scale, and have relied upon visual inspection of drainage networks to suggest that ANIMs lack the ability to produce diverse networks. In this study overland flow lengths were calculated on a sub-watershed basis, with standard deviation, and range calculated for sub-watershed populations as a means of quantifying the diversity of overland flow lengths produced by ANIM at the hill slope scale. Linear regression and Spearman ranking analyses were used to determine if the methods represented trends in overland flow length as suggested by manual delineation of contour lines. Three ANIMs were analyzed: the flow accumulation method (O'Callaghan and Mark, 1984), the terrain curvature method (Tarboton, 2000) and the ridge accumulation method (introduced in this study). All three methods were shown to produce non-zero standard deviations and ranges using a single support area threshold, with the terrain curvature method producing the most diverse networks, followed by the ridge accumulation method, and then the flow accumulation method. At an analysis unit size of 20 ha, the terrain curvature method produced a standard deviation that was most similar to those suggested by the contour crenulations, -13.5%, followed by the ridge accumulation method, -21.5%, and the flow accumulation method, -61.6%. The ridge accumulation produced the most similar range, -19.1%, followed by terrain curvature, -24.9%, and flow accumulation, -65.4%. While the flow accumulation networks had a much narrower range of predicted flow lengths, it had the highest Spearman ranking coefficient, Rs=0.722, and linear regression coefficient, R2=0.602. The terrain curvature method was second, Rs=0.641, R2=0.469, and then ridge accumulation, Rs=0.602, R2=0.490. For all methods, as threshold values were varied, areas of dissimilar morphology (as evidenced by the common stream metric stream frequency) experienced changes in overland flow lengths at different rates. This results in an inconsistency in ranking of sub-watersheds at different thresholds. When thresholds were varied to produce average overland flow lengths from 75 m to 150 m, the terrain curvature method showed the lowest incidence of rank change, 16.05%, followed by the ridge accumulation method, 16.73%, then flow accumulation, 25.18%. The results of this investigation suggest that for all three methods, a causal relationship exists between threshold area, underlying morphology, and predicted overland flow length. This causal relationship enables ANIMs to represent contour network trends in overland flow length with a single threshold value, but also results in the introduction of rank change error as threshold values are varied. Calibration of threshold value (varying threshold in order to better match observed overland flow lengths) is an effective means of increasing the accuracy of ANIM predictions, and may be necessary when comparing areas with different stream frequencies. It was shown that the flow accumulation method produces less diverse networks than the terrain curvature and ridge accumulation methods. However, the results of rank and regression analyses suggest that further investigation is required to determine if these more diverse ANIM are in fact more accurate than the flow accumulation method. / Master of Science

Die Kerne aktiver Galaxien (AGNs) und einige galaktische Objekte wie z.B. Supernovaüberreste gelten als vielversprechende Kandidaten für die Quellen der hochenergetischen kosmischen Strahlung. Der Nachweis der Emission von hochenergetischen Neutrinos von diesen Objekten wäre ein starker Hinweis für die Beschleunigung von Protonen oder schwereren Kernen. Bisher wurde jedoch keine Punktquelle hochenergetischer Neutrinos identifiziert. Durch die Beobachtung aktiver galaktischer Kerne mit gamma-Strahlung im TeV-Bereich ist bekannt, dass die Emission von AGNs zeitlich extrem variabel ist. Modelle sagen vorher, dass auch die Neutrinoemission diese Variabilität aufweist. Um im Falle der Detektion zeitabhängiger Neutrinoemission von AGNs möglichst viel über den Emissionsmechanismus zu lernen, ist es entscheidend, Daten verschiedener Energiebereiche und Botenteilchen (Neutrinos und Photonen) zur Verfügung zu haben. Durch das beschränkte Gesichtsfeld und den geringen Duty-Cycle der TeV-gamma Instrumente, können diese jedoch nicht alle potentiell interessanten Quellen lückenlos überwachen. Diese Arbeit beschreibt die Entwicklung und die ersten Resultate eines Systems, dass Daten des Neutrinoteleskops IceCube direkt am Südpol analysiert, um Alarme an die TeV-Teleskope MAGIC und VERITAS zu senden, falls eine erhöhte Neutrinoemission eines überwachten Objekts detektiert wird. Der Katalog überwachter Objekte, der im ersten Jahr dieses Programms aktiv war, umfasste 109 Objekte in der nördlichen Himmelshemisphäre (delta>0). Das System befindet sich seit März 2012 kontinuierlich Betrieb und hat von Mai 2012 bis Mai 2013 fünf Alarme generiert. Ein Alarm am 9.November 2012 resultierte in einer Folgebeobachtung durch die VERITAS-Teleskope. Es wurde kein signifikanter gamma-Fluss im TeV-Bereich detektiert. Weiterhin werden Verbesserungen der IceCube Online-Analysemethode beschrieben, die die Sensitivität des vorgestellten Programms in naher Zukunft weiter verbessern werden. / Active Galactiv Nuclei (AGN) and galactic objects like e.g. supernova remnants are promising candidates for the sources of the high-energy cosmic rays. The detection of high-energy neutrinos from these objects would be a strong hint for the acceleration of protons or heavier nuclei. No source of high-energy astrophysical neutrinos has been identified up to now. From the observation of AGN with TeV gamma-rays it is known that their emission is highly variable. Models predict that also the neutrino emission should show that variability. If time-dependent neutrino emission would be detected it would be desirable to have simultaneous data for different messengers (neutrinos and photons) and energy ranges, to learn as much as possible about the emission mechanism. However, due to the small field of view and the low duty cycle of the TeV gamma instruments, not all interesting sources can be continuously monitored. This work describes the development and the first results of a system, that analyses data of the IceCube neutrino telescope online at the South Pole, in order to send alerts to the TeV telescopes MAGIC and VERITAS in case a statistically interesting cluster of neutrinos is detected from an monitored source. This program is termed the Neutrino Triggered Target of Opportunity program (NToO). The catalog of sources monitored during the first year of operation contained 109 objects in the northern sky (delta>0). The system has been continuously operated since March 2012 and has sent five alerts between May 2012 and May 2013. One alarm issued on 9 November 2012 resulted in a follow-up observation by the VERITAS telescopes. No significant TeV-gamma flux has been detected. Improvements to the IceCube online analysis are described that will further improve the sensitivity of the NToO in the near future.

Modelos hidrológicos e de qualidade de água vêm sendo desenvolvidos para avaliar a poluição causada por fontes de origem difusa, em bacias hidrográficas agrícolas. Com esse objetivo, o modelo SWAT (Soil and Water Assessment Tool) foi aplicado para simular o escoamento e a produção de sedimentos produzidos pela microbacia hidrográfica do Ribeirão dos Marins, afluente do rio Piracicaba, SP, no biênio 1999/2000. A aplicação do modelo requer a entrada dos dados na forma espacializada. A manipulação desses dados foi feita com o auxílio de um Sistema de Informações Geográficas (SIG) e uma interface entre o modelo e o SIG que, automaticamente, subdivide a bacia em sub-bacias a partir do Modelo Numérico do Terreno (MNT) e, então, extrai os dados de entrada relacionados para cada sub-bacia dos outros Planos de Informação (PI’s), uso da terra e solos, associados a um extenso banco de dados. Posteriormente, os resultados finais da simulação são apresentados no formato de mapas, gráficos e tabelas. Os resultados obtidos da simulação, médias mensais do escoamento e a produção de sedimentos, foramcomparados aos dados observados em um posto hidrossedimentométrico localizado no terço superior da microbacia, utilizando o Coeficiente de Eficiência de Nash e Sutcliffe (COE) e o desvio dos dados simulados em relação aos observados (Dv). Foi feita uma calibração de alguns parâmetros físico-hídricos do solo e físico das sub-bacias, para as duas variáveis simuladas. Dois cenários alternativos de uso da terra foram simulados. No primeiro, o uso atual foi mantido, mas considerou-se uma faixa de mata ciliar de 30m em toda a extensão dos cursos d’água e de 50m ao redor das nascentes, de acordo com o Código Florestal. No segundo cenário, como as pastagens ocupam as encostas mais íngremes, com alto potencial erosivo, as áreas ocupadas por pastagem foram substituídas por vegetação florestal. As simulações dos dois cenários foram comparadas com as condições do cenário atual em termos de redução da produção de sedimentos. Os resultados obtidos para o escoamento simulado foram de 0,92 e -0,7% para o COE e o Dv, respectivamente, após a calibração. Na simulação da produção de sedimentos pelo modelo, após a calibração, o COE obtido foi de 0,83 e o Dv de -3,2%. Os cenários produziram diferentes padrões espaciais da produção de sedimentos. Uma redução de 84,4% na produção de sedimentos foi obtida com a substituição da pastagem por vegetação nativa (cenário 2). No cenário 1, a redução foi de 10,8%. Esses resultados evidenciam a necessidade de se tratar a paisagem em bacias hidrográficas de uma forma global, identificando as "áreas ambientalmente sensíveis", onde são necessárias práticas de controle dos processos erosivos e não somente com a proteção dispensada aos cursos d’água por meio da mata ciliar. / Hydrological and water quality models have been developed to evaluate the nonpoint source pollution in agricultural watershed. With this objective, SWAT (Soil and Water Assessment Tool) model was applied to simulate the streamflow and sediment yield in Ribeirão dos Marins watershed, on the Piracicaba river basin, Brazil, for the period 1999/2000. The application of the model requires the input data in spatial format. The manipulation of these data was made with an interface between the model and the Geographic Information System (GIS) that, automatically, subdivides the basin in subbasins, from the Digital Terrain Model (DTM) and extracts the input data for each subbasin from the land use and soil layers. Later, the results of the simulation are presented in the format of maps, graphs and tables. The results of the simulation, monthly averages of the streamflow and the sediment yield, were compared to the observed data in a gauge station located in Ribeirão dos Marins watershed, using the Nash Sutcliffe Coefficient (COE) and the deviation of the simulated data in relation to the observed data (Dv). A calibration of some physical-hydrological parameters of soil and physical of the subbasins was made for the two variables simulated. Two alternative scenarios of land use have been simulated. In the first, the current land use was kept, with a riparian buffer of 30m along of the drainage network and of 50m around the springs, in accordance with the Forest Code. In the second scenario, as the pastures occupy the steepest hillsides, with high erosive potential, pastures were changed by native forest. The simulations of the two scenarios were compared to the current scenario, regarding the reduction of sediment yield. The results of the simulated streamflow were of 0,92 and -0,7% for the COE and the Dv, respectively, after the calibration. In the simulation of the sediment yield, after the calibration, the COE was 0,83 and Dv was -3,2%. The scenarios produced different spatial patterns of the sediment yield. The reduction in sediment yield of 84,4% was obtained with the substitution of the pasture by native vegetation (scenario 2). In scenario 1, the reduction was of 10,8%. These results show that is necessity to manage watershed considering the whole landscape aspects, identifying environmentally sensitive areas, mainly in relation to erosion, instead of protecting only riparian areas.