Submitted in fulfillment of the degree of Master of Applied Science: Biotechnology, Durban University of Technology, Durban, South Africa, 2017. / Domestic wastewater contains a high nutrient load, primarily in the form of Carbon (C), Nitrogen (N), and Phosphorous (P) compounds. If left untreated, these nutrients can cause eutrophication in receiving environments. Biological wastewater treatment utilizes a suspension of microorganisms that metabolize this excess nutrient load. Nitrogen removal in these systems are due to the synergistic processes of nitrification and denitrification, each of which requires its own set of operating parameters and controlling microbial groups. An alternative N-removal pathway termed the anammox process allows for total N-removal in a single step under anoxic conditions. This process, mediated by the anammox bacterial group, requires no organic carbon, produces negligible greenhouse gases and requires almost 50 % less energy than the conventional process, making it a promising new technology for efficient and cost-effective N-removal. In this study, a sequencing batch reactor (SBR) was established for the autotrophic removal of N-rich wastewater through an anammox-centric bacterial consortia. The key microbial members of this consortia were characterized and quantified over time using molecular methods and next generation sequencing to determine if the operational conditions had any effect on the seed inoculum population composition. Additionally, local South African wastewater treatment plants were screened for the presence of anammox bacteria through 16S rRNA amplification and enrichment in different reactor types. A 3 L bench scale SBR was inoculated with active biomass (~ 5 % (v/v)) sourced from a parent anammox enrichment reactor, and maintained at a temperature of 35 °C ± 1 °C. The reactor was fed with a synthetic wastewater medium containing no organic C, minimal dissolved oxygen (< 0.5 mg/L), and N in the form of ammonium and nitrite in the ratio of 1:1.3. The reactor was operated for a period of 366 days and the effluent ammonium, nitrite and nitrate were measured during this period. The hydraulic retention time was controlled at 4.55 days from Day 1 to Day 250, and thereafter shortened to 1.52 days from Day 251 to Day 360 due to an increased nitrogen removal rate (NRR). During Phase I of operation (Day 1 to Day 150), the reactor performance gradually increased up to an NRR of ~160 mg N/day. During Phase II (Day 151 to Day 250), the overall reactor performance decreased with the NRR decreasing to ~90 mg N/day, while Phase III (Day 251 to Day 366) displayed a gradual recovery of NRR back to the reactor optimum of ~160 mg N/day. The accumulation of nitrate in the effluent during the latter parts of Phase II and Phase III, coupled with oxygen ingress (~2.1 mg/L) in the same period, indicated that it was not the anammox pathway that was dominating N-removal within the reactor, but more likely the second half of the nitrification pathway mediated by the nitrite oxidizing bacteria (NOB). This was further confirmed through molecular analysis, which indicated that the bacterial population had shifted significantly over the course of reactor operation. Quantitative PCR methods displayed a decrease in all the key N-removing population groups from Day 1 to Day 140, and a marginal increase in anammox and aerobic ammonia oxidizing bacteria from Day 140 – Day 260. From Day 300 onwards, NOB had started dominating the system, simultaneously suppressing the growth of other N-removing bacterial groups. Despite this, the NRR peaked during this period, indicating an alternative mechanism for ammonia removal within the reactor system. A total population analysis using NGS was also performed, which corroborated the QPCR results and displayed a population shift away from anammox bacteria towards predominantly NOB and members of the phylum Chloroflexi. The proliferation of aerobic NOB and Chloroflexi, and the suppression of anammox bacteria, indicated that DO ingress was indeed the primary cause of the population shift within the reactor. Despite this population shift, N-removal within the reactor remained high. New pathways have recently emerged which implicate these two groups as potential N oxidizers, with specific NOB groups showing the ability for oxidation of ammonia through the comammox process, and members of the Phylum Chloroflexi being capable of nitrite reduction. This could imply that an alternate pathway was responsible for the majority of N-removal within the system, in addition to the anammox and conventional nitrification pathways. Additionally, in an attempt to detect a local anammox reservoir, eleven wastewater systems from around South Africa were screened for the presence of anammox bacteria. Through direct and nested PCR-based screening, anammox bacteria was not detectable in any of the activated sludge samples tested. Based on the operating conditions of the source wastewater systems, a subset of three sludge samples were selected for further enrichment. After 60-110 days of enrichment in multiple reactor configurations, only one reactor sample tested positive for the presence of anammox bacteria. Although this result indicates that anammox bacteria might not be ubiquitous within every biological wastewater system, it is more likely that anammox bacteria might only be present at undetectable levels, and that an extended enrichment prior to screening is necessary for a true representation of anammox bacterial prevalence in an environmental sample. / M

De nombreuses substances chimiques sont susceptibles de mener à des phénomènes d'incompatibilité, lors de leur mise en contact avec d'autres produits ou matériaux. Pour maîtriser ces risques, une identification rapide et précise de ces incompatibilités est nécessaire. Elle est réalisée, jusqu’à présent, par des outils expérimentaux qui malgré leur incontestable importance, ne fournissent que des informations limitées. Pour les compléter et améliorer la compréhension des processus d'incompatibilité, ce travail de thèse, vise à étudier la réactivité du nitrate d'ammonium, produit très utilisé dans l'industrie, connu pour sa longue liste d'incompatibilités et impliqué dans des nombreux accidents majeurs (Toulouse 2001), à l'aide de la modélisation moléculaire. Une étude théorique approfondie, basée sur des calculs DFT, destinée à identifier les chemins réactionnels, les produits formés ainsi que la chaleur dégagée par les réactions a été menée.Après avoir caractérisé le mécanisme radicalaire de décomposition du nitrate d’ammonium pur en phase gaz, une étude détaillée de la réactivité du mélange du nitrate d’ammonium et du dichloroisocyanurate de sodium (DCCNa), a été réalisée. Un chemin réactionnel a été caractérisé, il s'agit de la réaction directe entre le nitrate d'ammonium et le DCCNa, en présence d'une molécule d'eau. Ensuite, ces méthodes théoriques ont été appliquées à d'autres systèmes d'incompatibilités chimiques avec le nitrate d'ammonium (NaNO2, substances chlorées) en focalisant sur les étapes limitantes des mécanismes afin de tester leur pertinence et potentiel en tant qu'outil de prédiction a priori du phénomène d'incompatibilité. Ce travail, pionnier dans l'étude microscopique des incompatibilités chimiques du nitrate d'ammonium, a permis de clarifier les mécanismes réactionnels lors de la décomposition du produit pur et en contact avec des contaminants. / Numerous chemical reactants tend to lead to undesired phenomena of incompatibility. In order to prevent the happening of those phenomena, a rapid and accurate identification of the incompatibilities is needed. Until now, experimental studies, which provide insightful, but limited information, were the only possible approach used for the study of incompatibilities. In this work a molecular modeling approach was used in order to complete and improve experimental results of incompatibility processes for the reactivity of ammonium nitrate. Ammonium nitrate is a widely used compound in the chemical industry, known for its long list of incompatibilities and often involved in major accidents (Toulouse, 2001).This theoretical work, based on Density Functional Theory (DFT) calculations, is intended to provide insights into the possible reaction pathways, enthalpies and products formed by incompatibility reaction between ammonium nitrate and other compounds. In this thesis the mechanism of the decomposition of pure ammonium nitrate in the gas phase was firstly characterized and then the reactivity of the mixture of ammonium nitrate – sodium dichloroisocyanurate (DCCNa) was considered. The results obtained suggest the existence of a reaction path, involving a direct reaction between the ammonium nitrate and DCCNa in the presence of a molecule of water.Furthermore, the theoretical approach was employed focusing on the study of the limiting steps of other chemical incompatibilities for ammonium nitrate systems (NaNO2, chlorinated substances). Those results were employed to understand the potentiality of the theoretical approach as a priori predicting tool for the incompatibility processes.In summary this work, pioneer in the microscopic study of chemical incompatibilities of ammonium nitrate, has clarified the reaction mechanisms involved in the decomposition of pure compounds, as well as in contact with other contaminants.

Modern mining explosives employ solutions of ammonium nitrate, where the solution is the oxidising component of a fuel/oxidiser mixture. This thesis is primarily concerned with the shock response of water and of aqueous solutions of ammonium nitrate. Of particular interest are the temperatures induced through shock compression. An experimental facility, using a single stage gas gun in the 'plate impact' configuration, is described, along with associated experimental diagnostics. Measurements of, and improvements to, the tilt at impact are reported. The problem of shock temperature is discussed, including a brief review of the relevant literature. It is demonstrated that direct measurement of shock temperature is a complex issue that is not yet fully understood, whereas determination of temperature from an equation of state is an established technique. In a series of experiments, plate impact techniques were utilised to determine the Hugoniot and, through shock/reload experiments, the equation of state of water and aqueous solutions of ammonium nitrate. In-situ manganin gauges were used to measure stresses in the liquids and, from the arrival times of the shock wave, determine the shock velocity. Linear shock velocity-particle velocity Hugoniots for the liquids were determined, up to particle velocities of 1km/s, with uncertainties on the intercept and slope of these Hugoniots of 5%. A Mie-Grûneisen equation of state was used to describe the shock/reload experiments. Approximate calculations of shock temperature are reported. Increasing ammonium nitrate concentrations resulted in greater calculated temperatures. It was demonstrated that the liquids investigated in this thesis show a temperature dependence of the Grûneisen parameter, ?, which cannot be accommodated in the model. The present work is believed to be the first demonstration of this effect in shock compressed liquids. The data presented provide constraints on future theoretical development of equations of state.

No description available.

Atmospheric aerosols are the major component in the shorter-term variability governing the radiative balance of the climate system, particularly on regional scales. However, knowledge of the myriad of properties and processes associated with aerosols is often limited, which results in major uncertainties when assessing their climate effects. One such aspect is the chemical make-up of the atmospheric aerosol burden.Airborne measurements of aerosol properties across Northern Europe are presented here in order to facilitate constraint of the properties, processes and effects of aerosols in this highly populated and industrialised region. An Aerodyne Aerosol Mass Spectrometer (AMS) delivered highly time-resolved measurements of aerosol chemical components, which included organic matter, sulphate, nitrate and ammonium.The chemical composition of the aerosol burden was strongly determined by the dominant meteorological conditions in Northern Europe. Pollution loadings in North- Western Europe were strongly enhanced when air masses originated from Continental Europe. Conversely, much cleaner conditions were associated with air masses from the Atlantic Ocean.Organic matter was found to be ubiquitous across Northern Europe and predominantly secondary in nature, which is consistent with other analyses in polluted regions of the Northern Hemisphere. Furthermore, its concentration was generally comparable to, or exceeded that of, sulphate. Significant chemical processing of the organic aerosol component was observed. Highly oxidised secondary organic aerosol dominated, as the distance from source and photochemical processing increased.Ammonium nitrate was found to be a major component of the aerosol burden in Northern Europe, with peak contributions occurring in North-Western Europe, due to the co-location of its emission precursors (NH3 and NOx) in the region. Ammonium nitrate was found to be the dominant sub-micron chemical constituent during periods associated with enhanced pollution episodes. Its concentration was shown to be modulated by the thermodynamic structure of the lower troposphere, with enhanced concentrations prevalent at the top of the boundary layer. This phenomenon greatly enhanced the radiative impact of the aerosol burden; the increased mass and water uptake by the aerosol significantly amplified the aerosol optical depth in the region.The results presented in this thesis highlight a highly dynamic region, where major changes in emissions have played a significant role in determining the chemical composition of the aerosol burden. As substantial reductions in sulphur dioxide emissions have occurred over the past two decades in Northern Europe, the relative contribution of sulphate aerosols to the regional aerosol burden has decreased. Consequently, it is more pertinent to consider the roles of organic matter and ammonium nitrate, as their influence becomes more pronounced than sulphate on regional and global climate.

Orientador: Enes Furlani Junior / Resumo: O N é um dos elementos mais dinâmicos no solo, conforme sua transformação no meio. A lixiviação de nitrato e do amônio no solo é considerada a principal perda do N disponível às plantas, quanto maior for à aplicação deste elemento no solo, maior será o potencial de poluição do solo e da água. Objetivou-se, neste trabalho, avaliar a lixiviação de amônio e nitrato em um Latossolo Vermelho em diferentes profundidas do solo, em função de doses e fontes de N distintas, em sistemas irrigado e não irrigado nas condições de campo. O experimento foi conduzido no ano agrícola 2014/15, na área experimental da fazenda de ensino, pesquisa e extensão, localizada no município de Selvíria-MS. Utilizou-se o delineamento em blocos casualizados, com 20 tratamentos dispostos em fatorial 5x2x2, com 4 repetições. Aplicou-se 5 doses de nitrogênio (0 (testemunha); 25; 50; 100 e 150 kg de N ha-1), as fontes de N utilizadas foram: nitrato de amônio e a ureia, aplicados em uma única adubação de cobertura via solo aos 45 após a emergência. As amostras de solo colhidas foram analisadas em laboratório, para a determinação da concentração da lixiviação do NO3- e do NH4+ no solo. Avaliou – se os parâmetros de crescimento, estado nutricional e da produtividade do algodoeiro durante seu ciclo. Os resultados permitiram concluir que o sistema irrigado foi o que propiciou maior lixiviação dos teores de nitrato e amônio nas profundidades de 0 a 0,8 m do solo e o sistema não irrigado foi o que apresentou maior con... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The N is one of the most dynamic elements in the soil, according to its transformation in the environment. The leaching of nitrate and ammonium in the soil is considered the main loss of the N available to the plants, the greater the application of this element in the soil, the greater the pollution potential of soil and water. The objective of this work was to evaluate the leaching of ammonium and nitrate in a Red Latosol in different depths of the soil, as a function of different N sources and sources, in irrigated and non-irrigated systems under field conditions. The experiment was conducted in the agricultural year 2014/15, in the experimental area of the teaching, research and extension farm, located in the municipality of Selvíria, Brasil state of mato grosso do sul. A randomized complete block design was used, with 20 treatments arranged in 5x2x2 factorial, with 4 replications. Five nitrogen doses (0 (control), 25, 50, 100 and 150 kg of N ha-1) were applied, the N sources used were: ammonium nitrate and urea, applied in a single cover fertilization only at 45 after the emergency. The soil samples collected were analyzed in the laboratory for the determination of the leaching concentration of NO3- and NH4+ in the soil. The parameters of growth, nutritional status and yield of cotton during its cycle were evaluated. The results allowed to conclude that the irrigated system provided the highest leaching of the nitrate and ammonium contents in the 0 to 0,8 m depths of the ... (Complete abstract click electronic access below) / Mestre

Poly(vinyl acetate) (PVAc) has a major application as an indoor wood adhesive. Low water stability is however, one of the greatest drawbacks of PVAc. By grafting PVAc from a chitosan (CS) backbone (CS-graft- PVAc) water stability of adhesive is increased while good mechanical and adhesive properties are retained. Simultaneously the percentage of bio-based content is increased. This work investigates the proposed re- action mechanisms between chitosan and cerium(IV) ammonium nitrate (CAN) which is used as an initiator for the grafting reaction. Litera- ture studies showed one dominating reaction mechanism and some not as common. The reaction mechanisms and their shortcomings are pre- sented and discussed in the report. / Poly(vinyl acetat)(PVAc) har ett stort användningsområde som ett trälim för möbler som ska användas inomhus. Den dåliga vatten stabiliteten är ett av de största problemen för användning av PVAc. Genom att ympa PVAc med chitosan(CS) (CS-graft-PVAc) kan vatten stabiliteten ökas samtidigt som en god limfunktion finns kvar och delen fossilbaserad monomer blir mindre och byts ut mot en biobaserad polymer. I detta arbete undersöks de föreslagna reaktionsmekanismerna mellan CS och cerium(IV) ammonium nitrat(CAN) som används som en katalysator för att grafta PVAc med CS. Litteraturstudier visade en dominerade reaktionsmekanism och några mindre förekommande. Reaktionsmekanis- merna och eventuella tillkortakommanden som finns gällande hur de fortlöper presenteras och diskuteras i detta arbete.

Avalia a alteração da qualidade da água da região de lançamento dos efluentes domésticos no reservatório de Três Irmãos, em virtude da aplicação de nitrato de amônio, para controle de odor, na rede coletora de esgotos do município de Pereira Barreto desde 1996. Foram realizadas 6 campanhas, com freqüência bimestral, no período de Outubro de 2004 a Agosto de 2005. As amostras foram coletadas em seis pontos, sendo cinco no reservatório, e um na ETE-Pereira Barreto. Em cada estação no reservatório, as amostras foram tomadas à superfície, à meia profundidade e fundo. Obtiveram-se amostras de água e esgoto para análise de parâmetros físicos, químicos e hidrobiológicos. Para melhor avaliar a qualidade da água, como também do efluente final da ETE, foram efetuados o Teste de Postos com Sinais de Wilcoxon para Pares Combinados (Método Não-Paramétrico), Análise de Componentes Principais (ACP) e Análise de Agrupamento (Cluster). Os resultados mostraram que os níveis de nitrogênio nitrato na água e no efluente final situaram-se bem abaixo do limite máximo estabelecido pelo CONAMA 357/05 para águas da Classe 2 (10 mg/L). Concluiu-se que a prática da adição de nitrato de amônio para reduzir os odores em rede coletoras de esgotos sanitários, sob o ponto de vista ambiental, não apresentou potencial para acarretar impacto negativo no corpo receptor, e que a região de estudo no reservatório é um ambiente bem oxigenado, inclusive nas camadas mais profundas, com baixos teores de turbidez e pH levemente alcalino,entretanto, com alta condutividade elétrica e elevadas concentrações de nutrientes (fósforo e amônia), principalmente no período de verão. Este fato é devido à influência principalmente do esgoto doméstico que é lançado nesta área. / It evaluates the alteration of the quality of the water in the region of discharges of domestic effluents into the Três Irmãos reservoir, due to the application, since 1996, of ammonium nitrate into the sewer system of the city of Pereira Barreto. Six trips to collect samples were performed bimonthly between October 2004 and August 2005.The samples were collected at six different points: five in the reservoir and one in the Sewage Treatment Plant in Pereira Barreto. In each station of the reservoir, the samples were collected on the surface, at half depth and at the bottom. Water and sewage samples were obtained for analysis of physical, chemical and hydrobiological parameters. In order to better evaluate the quality of water, as well as the quality of the final effluent from the sewage of the Sewage Treatment Plant, the Wilcoxon Signed-rank Test for Paired Data (Nonparametric Test), the Principal Component Analysis and the Hierarchical Cluster Analysis Methods were performed. The results showed that the levels of nitrate-nitrogen in the water and in the final effluent were way below the maximum limit established by CONAMA 357/05 for Class 2 waters (10 mg/L). It was concluded that, environmentally speaking, the addition of ammonium nitrate to reduce the odors in sanitary sewer systems was not potentially significant to cause a negative impact on the reservoir. It was also concluded that the region under study in the reservoir is well oxygenated, even in deeper layers, with low turbidity levels and slightly alkaline pH; however, high electrical conductivity and high concentrations of nutrients (phosphorus and ammonia) were observed, mainly in summer. This is mainly due to the influence of the domestic sewage which is discharged in that area.

Avalia a alteração da qualidade da água da região de lançamento dos efluentes domésticos no reservatório de Três Irmãos, em virtude da aplicação de nitrato de amônio, para controle de odor, na rede coletora de esgotos do município de Pereira Barreto desde 1996. Foram realizadas 6 campanhas, com freqüência bimestral, no período de Outubro de 2004 a Agosto de 2005. As amostras foram coletadas em seis pontos, sendo cinco no reservatório, e um na ETE-Pereira Barreto. Em cada estação no reservatório, as amostras foram tomadas à superfície, à meia profundidade e fundo. Obtiveram-se amostras de água e esgoto para análise de parâmetros físicos, químicos e hidrobiológicos. Para melhor avaliar a qualidade da água, como também do efluente final da ETE, foram efetuados o Teste de Postos com Sinais de Wilcoxon para Pares Combinados (Método Não-Paramétrico), Análise de Componentes Principais (ACP) e Análise de Agrupamento (Cluster). Os resultados mostraram que os níveis de nitrogênio nitrato na água e no efluente final situaram-se bem abaixo do limite máximo estabelecido pelo CONAMA 357/05 para águas da Classe 2 (10 mg/L). Concluiu-se que a prática da adição de nitrato de amônio para reduzir os odores em rede coletoras de esgotos sanitários, sob o ponto de vista ambiental, não apresentou potencial para acarretar impacto negativo no corpo receptor, e que a região de estudo no reservatório é um ambiente bem oxigenado, inclusive nas camadas mais profundas, com baixos teores de turbidez e pH levemente alcalino,entretanto, com alta condutividade elétrica e elevadas concentrações de nutrientes (fósforo e amônia), principalmente no período de verão. Este fato é devido à influência principalmente do esgoto doméstico que é lançado nesta área. / It evaluates the alteration of the quality of the water in the region of discharges of domestic effluents into the Três Irmãos reservoir, due to the application, since 1996, of ammonium nitrate into the sewer system of the city of Pereira Barreto. Six trips to collect samples were performed bimonthly between October 2004 and August 2005.The samples were collected at six different points: five in the reservoir and one in the Sewage Treatment Plant in Pereira Barreto. In each station of the reservoir, the samples were collected on the surface, at half depth and at the bottom. Water and sewage samples were obtained for analysis of physical, chemical and hydrobiological parameters. In order to better evaluate the quality of water, as well as the quality of the final effluent from the sewage of the Sewage Treatment Plant, the Wilcoxon Signed-rank Test for Paired Data (Nonparametric Test), the Principal Component Analysis and the Hierarchical Cluster Analysis Methods were performed. The results showed that the levels of nitrate-nitrogen in the water and in the final effluent were way below the maximum limit established by CONAMA 357/05 for Class 2 waters (10 mg/L). It was concluded that, environmentally speaking, the addition of ammonium nitrate to reduce the odors in sanitary sewer systems was not potentially significant to cause a negative impact on the reservoir. It was also concluded that the region under study in the reservoir is well oxygenated, even in deeper layers, with low turbidity levels and slightly alkaline pH; however, high electrical conductivity and high concentrations of nutrients (phosphorus and ammonia) were observed, mainly in summer. This is mainly due to the influence of the domestic sewage which is discharged in that area.

Research on health effects of particulate matter (PM) has been a very active area in the last two decades. One plausible mechanism by which exposure to PM affects human health includes modification of autonomic endothelium function. Decreased endothelium activity causes heightened risks of cardiovascular disease. A human exposure chamber designed to conduct experiments to quantify diminished function of endothelium from short term exposure to PM is described. The chamber consists of two stages for containment and pre-treatment of PM and exposure of human subjects. Concentrations of CO, CO2, NO, NO2, O3, and PM2.5, are monitored and controlled in the exposure room. The PM used in the human exposure experiments was characterized chemically and morphologically. During January and February of 2009, chemical analysis of PM2.5 was done during inversion periods in Salt Lake City, UT. An Ambient Ion Monitor (AIM) was deployed to measure the concentrations of anions in both particulate and gas phases. The chemical data provided by AIM was complemented by measurements by the Department of Air Quality that included PM10, PM2.5, O3, NO, NO2, NH3 and CO. The goal of the study was to determine whether ammonia or nitric acid is the limiting reagent in formation of PM during inversions. Nitric acid is the limiting reagent. Concentrations of ammonia are an order of magnitude higher than nitric acid.