Orientador: Tsunao Matsumoto / Resumo: Este estudo mostra o funcionamento dos processos de oxidação de matéria orgânica junto com os processos simultâneos de nitrificação e desnitrificação (SND) dentro do reator aeróbio de leito fluidizado de tubos concêntricos com uma terceira câmara para gerar condições anóxicas (necessárias para garantir o processo de desnitrificação). O reator foi operado por um período de 140 dias, durante o qual a remoção de demanda química de oxigênio (DQO) e de nitrogênio total (NT), atingiu 80% e 44% respectivamente, para um tempo de detenção hidráulica (TDH) de 3 horas. A configuração dos diâmetros dos tubos concêntricos resultou em diferentes relações de áreas e, portanto em diferentes vazões para cada câmara. Na operação do reator foram aplicadas duas relações de vazões alterando o nível de esgoto dentro do reator. Os efeitos destas relações de vazões, alterou a concentração de oxigênio dissolvido (OD) entre os compartimentos aeróbio e anóxico do reator e a relação C:N, as quais foram estudadas durante o funcionamento deste sistema. Os resultados indicaram que a relação de vazões 2(4,8: 3,8: 1 para as câmaras 1, 2 e 3, respectivamente) beneficiou as remoções de DQO e NT. A concentração de OD no compartimento aeróbio apresentou valores médios de 3,57 ± 1,24 mg.L -1 , e no topo da câmara 3, a concentração de OD foi de 1,41 ± 0,78 mg.L -1 . As relações C:N que apresentaram maiores eficiências de remoção de NT foram as superiores a 10, sendo a máxima remoção de T na relação C:N de 17. O te... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study shows the operation of the organic matter oxidation processes together with the simultaneous processes of nitrification and denitrification (SND) inside the aerobic fluidized bed reactor of concentric tubes with a third chamber to generate anoxic conditions (necessary to guarantee the denitrification process). The reactor operated over a period of 140 days, during which chemical oxygen demand (COD) and total nitrogen (TN) removal reached 80% and 44% respectively, for a 3 hour hydraulic detention time (HDT). The configuration of the diameters of the concentric tubes resulted in different area ratios and therefore in different flow rates for each chamber. In the reactor operation were applied two flow ratios, altering the sewage level inside the reactor. The effects of these flow rates were changing the concentration of dissolved oxygen (DO) between the aerobic and anoxic compartments of the reactor and the C: N ratio, which was studied during the operation of this system. The results indicated that the ratio of flows 2 (4.8: 3.8: 1 for chambers 1, 2 e 3, respectively) benefited the COD and TN removal. The DO concentration in the aerobic compartment presented average values of 3.57 ± 1.24 mg.L-1 , and on top of chamber 3, the DO concentration was 1.41 ± 0.78 mg.L-1 . The C:N ratios that showed higher nitrogen removal efficiencies were higher than 10, with the maximum TN removal at the C:N ratio of 17. The cell retention time reached (CRT) in the reactor was 3.16 ± 3.... (Complete abstract click electronic access below) / Mestre

abstract: The global transport and deposition of anthropogenic nitrogen (N) to downwind ecosystems are significant and continue to increase. Indeed, atmospheric deposition can be a significant source of N to many watersheds, including those in remote, unpopulated areas. Bacterial denitrification in lake sediments may ameliorate the effects of N loading by converting nitrate (NO3-) to N2 gas. Denitrification also produces nitrous oxide (N2O), a potent greenhouse gas. The ecological effects of atmospheric N inputs in terrestrial ecosystems and the pelagic zone of lakes have been well documented; however, similar research in lake sediments is lacking. This project investigates the effects N of deposition on denitrification and N2O production in lakes. Atmospheric N inputs might alter the availability of NO3- and other key resources to denitrifiers. Such altered resources could influence denitrification, N2O production, and the abundance of denitrifying bacteria in sediments. The research contrasts these responses in lakes at the ends of gradients of N deposition in Colorado and Norway. Rates of denitrification and N2O production were elevated in the sediments of lakes subject to anthropogenic N inputs. There was no evidence, however, that N deposition has altered sediment resources or the abundance of denitrifiers. Further investigation into the dynamics of nitric oxide, N2O, and N2 during denitrification found no difference between deposition regions. Regardless of atmospheric N inputs, sediments from lakes in both Norway and Colorado possess considerable capacity to remove NO3- by denitrification. Catchment-specific properties may influence the denitrifying community more strongly than the rate of atmospheric N loading. In this regard, sediments appear to be insulated from the effects of N deposition compared to the water column. Lastly, surface water N2O concentrations were greater in high-deposition lakes compared to low-deposition lakes. To understand the potential magnitude of deposition-induced N2O production, the greenhouse gas inventory methodology of Intergovernmental Panel on Climate Change was applied to available datasets. Estimated emissions from lakes are 7-371 Gg N y-1, suggesting that lakes could be an important source of N2O. / Dissertation/Thesis / Ph.D. Biology 2010

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The application of pig slurry (PS) in agricultural areas, mostly grown under no-till, can cause a substantial increase in N losses by nitrous oxide emissions (N2O) into the atmosphere, both for the characteristics of the PS and for the straw kept on the ground at SPD. However, little is known about the influence of the biochemical composition of the straw used in no till on emissions of N2O, after the application of PS as well as on how the collecting system of this gas can affect the quantification of N2O emissions. Thus, two field studies were conducted. In the study I , was evaluated the influence of the sampling system on the measurements of N2O following the application of PS on black oat straw. In the Study II was evaluated the influence of stages of decomposition of black oat straw at full flowering (experiment 1) and harvest stages (experiment 2) on emissions of N2O, after application of 50 m3 ha-1 of PS. In study I , two experiments were conducted between January and February 2011, (experiment 1) in the experimental area of Irrigation and Drainage Department, in the Federal University of Santa Maria (UFSM), and between September and October 2012 (experiment 2) in the experimental area of Zootecnic Department (UFSM). The N2O sampling were performed after the application of PS and irrigations at 2 h intervals for every 24 h. In the study II , two experiments were conducted between September and December 2012, in the experimental area of Zootecnic Department (UFSM). All treatments used in both experiments of the study II were arranged in a random block design with three replicates, as follows: T1- Soil (control); T2- PS surface (Soil + PS); T3- straw at time 0 + DLS surface (T0 + PS); T4- straw at time 1 + DLS surface (T1 + PS); T5- straw at time 2 + DLS surface (T2 + PS); T6- straw- at time 3 + DLS surface (T3 + PS); and T7- straw at time 4 + DLS surface (T4 + PS). In study I , the sampling system was influenced for the quantification of N2O emissions, indicating that the sampling during times when emissions are high, for example, in the first 6 hours there would be an overestimation of emissions, suggesting that a sampling 8 hours after the rain stopped would be the best time to estimate the cumulative N2O emission. In study II , in both experiments was observed that the application of PS over the straw increased N2O emissions to the atmosphere. However, in the conditions which this study was conducted, it was not possible to statistically distinguish N2O emissions in relation to different stages of decomposition of the oat straw. / A aplicação de dejetos líquidos de suínos (DLS) em áreas agrícolas, cultivadas principalmente sob o sistema de plantio direto (SPD), pode provocar um aumento substancial das perdas de N pelas emissões de óxido nitroso (N2O) para a atmosfera, tanto pelas características dos DLS quanto da palhada mantida sobre o solo no SPD. No entanto, pouco se sabe sobre a influência da composição bioquímica da palhada utilizada em SPD sobre as emissões de N2O, após a aplicação de DLS, assim como sobre o quanto o regime de coletas desse gás pode afetar a quantificação das emissões de N2O. Dessa forma, foram conduzidos dois estudos a campo. O estudo I objetivou avaliar a influência do regime de coletas sobre as quantificações de N2O após a aplicação de DLS sobre palha de aveia preta. Já o estudo II, objetivou avaliar a influência dos estágios de decomposição de aveia preta em pleno florescimento (experimento 1) e na colheita (experimento 2) sobre as emissões de N2O, após a aplicação de 50 m3 ha-1 de DLS. No estudo I, foram conduzidos dois experimentos, entre janeiro e fevereiro de 2011 (experimento 1) na área experimental do setor de Irrigação e Drenagem da Universidade Federal de Santa Maria (UFSM), e entre setembro e outubro de 2012 (experimento 2) na área experimental do Departamento de Zootecnia da Universidade Federal de Santa Maria UFSM. As coletas de N2O foram realizadas logo após a aplicação dos DLS e das irrigações, em intervalos de 2 h, durante 24 h. No estudo II, foram conduzidos 2 experimentos entre setembro e dezembro de 2012, na área experimental do Departamento de Zootecnia da Universidade Federal de Santa Maria UFSM. Todos os tratamentos utilizados nos dois experimentos do estudo II foram dispostos em um delineamento de blocos ao acaso com três repetições, sendo eles: T1- Solo (testemunha); T2- DLS em superfície (Solo + DLS); T3- Palha no tempo 0 + DLS em superfície (T0 + DLS); T4- Palha no tempo 1 + DLS em superfície (T1 + DLS); T5- Palha no tempo 2 + DLS em superfície (T2 + DLS); T6- Palha no tempo 3 + DLS em superfície (T3 + DLS); e T7- Palha no tempo 4 + DLS em superfície (T4 + DLS). No estudo I, o regime de coletas influenciou a quantificação das emissões de N2O, indicando que a realização de coletas em momentos em que as emissões são altas, ou seja, nas primeiras seis horas ocorreria uma superestimação das emissões, sugerindo então que uma única coleta após 8 horas do fim das chuvas seria o melhor período para estimar a emissão acumulada de N2O. No estudo II, foi observado em ambos experimentos que a aplicação de DLS sobre a palhada aumentou as emissões de N2O para atmosfera. Entretanto, nas condições em que este estudo foi conduzido, não foi possível distinguir estatisticamente as emissões de N2O em relação ao diferentes estágios de decomposição das palhas de aveia preta.

abstract: The dissimilatory reduction of nitrate, or denitrification, offers the potential of a sustainable, cost effective method for the non-disruptive mitigation of earthquake-induced soil liquefaction. Worldwide, trillions of dollars of infrastructure are at risk for liquefaction damage in earthquake prone regions. However, most techniques for remediating liquefiable soils are either not applicable to sites near existing infrastructure, or are prohibitively expensive. Recently, laboratory studies have shown the potential for biogeotechnical soil improvement techniques such as microbially induced carbonate precipitation (MICP) to mitigate liquefaction potential in a non-disruptive manner. Multiple microbial processes have been identified for MICP, but only two have been extensively studied. Ureolysis, the most commonly studied process for MICP, has been shown to quickly and efficiently induce carbonate precipitation on particle surfaces and at particle contacts to improve the stiffness, strength, and dilatant behavior of liquefiable soils. However, ureolysis also produces copious amounts of ammonium, a potentially toxic byproduct. The second process studied for MICP, denitrification, has been shown to precipitate carbonate, and hence improve soil properties, much more slowly than ureolysis. However, the byproducts of denitrification, nitrogen and carbon dioxide gas, are non-toxic, and present the added benefit of rapidly desaturating the treated soil. Small amounts of desaturation have been shown to increase the cyclic resistance, and hence the liquefaction resistance, of liquefiable soils. So, denitrification offers the potential to mitigate liquefaction as a two-stage process, with desaturation providing short term mitigation, and MICP providing long term liquefaction resistance. This study presents the results of soil testing, stoichiometric modeling, and microbial ecology characterization to better characterize the potential use of denitrification as a two-stage process for liquefaction mitigation. / Dissertation/Thesis / Doctoral Dissertation Civil and Environmental Engineering 2016

This study investigates the effect of ecosystem age on the nitrate removal efficiency, nitrate removal rate and first-order area-based removal rate coefficients (both with and without temperature adjustment) of created wetlands. Data was collected from the first to eleventh year after wetland creation in an experimental wetland facility in south-west Sweden. The 18 small (22-29 m2) free water surface wetlands were divided into three groups based on initial planting: EVW (emergent vegetation wetlands), SVW (submerged vegetation wetlands) and CW (unplanted control wetlands). Summer and winter values from the 11 studied years were analysed separately in the repeated measures ANOVA. Over these 11 years the mean nitrate removal efficiency was 12 % and the mean nitrate removal rate was 0.17 g m-2 d-1. Mean removal rate coefficient (K) was 0.020 g d-1 and mean temperature adjusted removal rate coefficient (Ka) was 0.042 g d-1. The best performing wetlands were those initially planted with, and after four years almost completely covered by, emergent vegetation (EVW). This study indicates a positive correlation between wetland age and nitrate removal potential. It further indicates aging may be hastened by initial planting of wetland vegetation.

Thesis (DTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017. / Industrial wastewater management pertaining to the mining industry has become increasingly stringent, with companies being required to develop environmentally benign wastewater management practices worldwide. The industries that utilise cyanide compounds for the recovery of precious and base metals in a process known as the cyanidation process, have contributed substantially to environmental deterioration and potable water reserve contamination due to the discharge of poorly treated, or untreated, cyanide containing wastewater. Hence, a biotechnological approach was undertaken in this study to remediate free cyanide (CN-) and thiocyanate (SCN-), which are the major chemical contaminants which are normally found in cyanidation wastewaters. Furthermore, this biotechnological approach was investigated to understand the fundamental aspects of using this approach such that the information gathered can be utilized in pilot plant studies. Therefore, bioprospecting of potential CN- and SCN--degrading organisms was undertaken using two approaches; (i) culture-dependent approach and (ii) culture-independent approach. Using the culture-dependent approach, Pseudomonas aeruginosa STK 03, Exiguobacterium acetylicum and Bacillus marisflavi were isolated from an oil spill site and river sediment samples, respectively. STK 03 was evaluated for the biodegradation of CN- and SCN- under alkaline conditions. The organism had a CN- degradation efficiency of 80% and 32% from an initial concentration of 250 and 450 mg CN-/L, respectively. Additionally, the organism was able to degrade SCN-, achieving a degradation efficiency of 78% and 98% from non- and CN- spiked cultures, respectively. Furthermore, the organism was capable of heterotrophic nitrification but was unable to denitrify aerobically, with the autotrophic degradation of CN- by STK 03 being abortive.

Regulating factors of denitrification and their effect on emissions of N2O from pasture soils in a cattle overwintering area were investigated. The study was based on field experiments performed at three locations along the gradient of animal impact and on laboratory experiments focused on effect of nutrients addition on N2O emissions.

The linkage between denitrification activity, N gas emissions, and the size of the denitrifier community in soils of an upland pasture was investigated. Special emphasis was placed on soil pH as a regulating factor, the spatial distribution of denitrification, and the degree of cattle impact. The thesis has been based on field and laboratory measurements using both conventional and modern methods of soil ecology.

abstract: One of the most economical and viable methods of soil improvement is dynamic compaction. It is a simple process that uses the potential energy of a weight (8 tonne to 36 tonne) dropped from a height of about 1 m to 30 m, depending on the project requirement, on to the soil to be compacted hence densifying it. However, dynamic compaction can only be applied on soil deposits where the degree of saturation is low and the permeability of the soil mass is high to allow for good drainage. Using dynamic compaction on saturated soil is unsuitable because upon application of the energy, a part of the energy is transferred to the pore water. The technique also does not work very well on soils having a large content of fines because of the absence of good drainage. The current research aims to develop a new technology using biogenic gas production to desaturate saturated soils and extend the use of dynamic compaction as a ground improvement technique to saturated soils with higher fines content. To evaluate the feasibility of this technology an experimental program has been performed. Soil columns with varying soil types have been saturated with substrate solution, resulting in the formation of nitrogen gas and the change in soils volume and saturation have been recorded. Cyclic triaxial tests have been performed to evaluate the change in volume and saturation under elevated pressure conditions and evaluate the response of the desaturated soil specimens to dynamic loading. The experimental results showed that soil specimens treated with MIDP under low confinement conditions undergo substantial volume expansion. The amount of expansion is seen to be a factor of their pore size, which is directly related to their grain size. The smaller the grain size, smaller is the pore size and hence greater the volume expansion. Under higher confining pressure conditions, the expansion during gas formation is suppressed. However, no conclusive result about the effect of the desaturation of the soil using biogenic gas on its compactibility could be obtained from the cyclic triaxial tests. / Dissertation/Thesis / Data sheets / Masters Thesis Civil, Environmental and Sustainable Engineering 2018

abstract: Microbially induced calcium carbonate precipitation (MICP) is attracting increasing attention as a sustainable means of soil improvement. While there are several possible MICP mechanisms, microbial denitrification has the potential to become one of the preferred methods for MICP because complete denitrification does not produce toxic byproducts, readily occurs under anoxic conditions, and potentially has a greater carbonate yield per mole of organic electron donor than other MICP processes. Denitrification may be preferable to ureolytic hydrolysis, the MICP process explored most extensively to date, as the byproduct of denitrification is benign nitrogen gas, while the chemical pathways involved in hydrolytic ureolysis processes produce undesirable and potentially toxic byproducts such as ammonium (NH4+). This thesis focuses on bacterial denitrification and presents preliminary results of bench-scale laboratory experiments on denitrification as a candidate calcium carbonate precipitation mechanism. The bench-scale bioreactor and column tests, conducted using the facultative anaerobic bacterium Pseudomonas denitrificans, show that calcite can be precipitated from calcium-rich pore water using denitrification. Experiments also explore the potential for reducing environmental impacts and lowering costs associated with denitrification by reducing the total dissolved solids in the reactors and columns, optimizing the chemical matrix, and addressing the loss of free calcium in the form of calcium phosphate precipitate from the pore fluid. The potential for using MICP to sequester radionuclides and metal contaminants that are migrating in groundwater is also investigated. In the sequestration process, divalent cations and radionuclides are incorporated into the calcite structure via substitution, forming low-strontium calcium carbonate minerals that resist dissolution at a level similar to that of calcite. Work by others using the bacterium Sporosarcina pasteurii has suggested that in-situ sequestration of radionuclides and metal contaminants can be achieved through MICP via hydrolytic ureolysis. MICP through bacterial denitrification seems particularly promising as a means for sequestering radionuclides and metal contaminants in anoxic environments due to the anaerobic nature of the process and the ubiquity of denitrifying bacteria in the subsurface. / Dissertation/Thesis / M.S. Engineering 2013