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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
611

Tratamento de ?gua residu?ria de bovinocultura de leite, utilizando leitos cultivados / Wastewater treatment of dairy cattle using constructed wetlands

Almeida, Gilda Vieira de 29 February 2016 (has links)
Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-11-07T16:36:09Z No. of bitstreams: 1 2016 - Gilda Vieira de Almeida.pdf: 1316919 bytes, checksum: c03bdccc4b150c7dd6900dacd899cb3d (MD5) / Made available in DSpace on 2017-11-07T16:36:09Z (GMT). No. of bitstreams: 1 2016 - Gilda Vieira de Almeida.pdf: 1316919 bytes, checksum: c03bdccc4b150c7dd6900dacd899cb3d (MD5) Previous issue date: 2016-02-29 / Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ - FAPERJ / The amount of waste produced daily by dairy cattle is one of the biggest problems in intensive management systems. The disposal of waste from animal facilities has constituted a challenge for breeders and experts as it involves technical, health and economics. In this context, the objective of this study was to evaluate the efficiency of use of a wetlands constructed cultivated with rice in the treatment of wastewater from dairy production. For that it was built a pilot treatment plant consists of: septic tank, anaerobic filter, inert filter and wetlands constructed. Efficiency is evaluated based on the following parameters: chemical oxygen demand (COD), phosphorus, ammonia, nitrate, nitrite, total nitrogen Kjeldahl (NTK), electrical conductivity, turbidity, color and pH. The septic tank had a color and turbidity removal in 45 and 59%, respectively. The anaerobic filter presented chemical demand for oxygen removal, color nitrate and turbidity, of 36%, 41%, 17% and 32%, respectively. In the inert filter material was the reduction of chemical oxygen demand parameters at 5%, 10% nitrate, color 19% Turbidity 9% increase in ammonia and 2%. The SAC recorded removals of 35% of chemical oxygen demand, 43% turbidity, 23% colored, 1.5% phosphorus, 18% of ammonia, nitrate and 7% 17% Total Kjeldahl nitrogen. The treatment plant showed a reduction of chemical oxygen demand by 67%, phosphorus by 27%, ammonia by 25%, nitrate 81% nitrite in 72%, the total Kjeldahl nitrogen by 41%, electrical conductivity by 18%, color 71% and 85% in turbidity. The analyzes conducted over five months of the experiment showed that the removal of organic matter and turbidity in the constructed wetland system planted with rice remained in accordance with the literature, however, the nitrogen removal was lower than that found in the literature. Low nitrogen removal can be attributed to high organic load associated with low hydraulic retention time / A quantidade de dejetos produzidos diariamente pela bovinocultura leiteira ? um dos maiores problemas em sistemas de manejo intensivo. A disposi??o dos res?duos das instala??es animais tem se constitu?do em um desafio para criadores e especialistas, pois envolve aspectos t?cnicos, sanit?rios e econ?micos. Nesse contexto, o objetivo deste trabalho foi avaliar a efici?ncia da utiliza??o de um sistema de alagado constru?do (SAC) cultivado com arroz no tratamento da ?gua residu?ria de bovinocultura de leite. Para isso, foi constru?da uma esta??o piloto de tratamento composta por: tanque s?ptico, filtro anaer?bio, filtro de material inerte e SAC. A efici?ncia foi avaliada a partir dos seguintes par?metros: demanda qu?mica de oxig?nio (DQO), f?sforo, am?nia, nitrato, nitrito, nitrog?nio total Kjeldahl (NTK), condutividade el?trica, turbidez, cor e pH. O tanque s?ptico apresentou uma remo??o de cor e turbidez, em 45 e 59%, respectivamente. O filtro anaer?bio apresentou remo??es de demanda qu?mica de oxig?nio, nitrato cor e turbidez, de 36%, 41%, 17% e 32%, respectivamente. No filtro de material inerte houve a redu??o dos par?metros demanda qu?mica de oxig?nio em 5%, nitrato em 10%, cor em 19%, turbidez em 9% e acr?scimo na am?nia de 2%. O SAC apresentou remo??es de 35% de demanda qu?mica de oxig?nio, 43% de turbidez, 23% de cor, 1,5% de f?sforo, 18% de am?nia, 7% nitrato e 17% nitrog?nio total Kjeldahl. A esta??o de tratamento apresentou uma redu??o de demanda qu?mica de oxig?nio em 67%, f?sforo em 27%, am?nia em 25%, nitrato em 81%, nitrito em 72%, nitrog?nio total Kjeldahl em 41%, condutividade el?trica em 18%, cor em 71% e de turbidez em 85%. As an?lises realizadas ao longo de cinco meses de experimento permitiram concluir que a remo??o de mat?ria org?nica e turbidez no sistema alagado constru?do cultivado com arroz mantiveram-se de acordo com a literatura, no entanto a remo??o de nitrog?nio foi abaixo da encontrada na literatura. A baixa remo??o do nitrog?nio pode ser atribu?da a elevada carga org?nica associada ao baixo tempo de deten??o hidr?ulica
612

Comparative removal of pharmaceuticals and antimicrobials in conventional and constructed wetland wastewater treatment in cold climate

Gorsalitz, Emily Kristine 01 July 2012 (has links)
In this study we compare the ability of nitrifying activated sludge (NAS) and nitrifying trickling filter (NTF) wastewater treatment to remove the following contaminants: acetaminophen, caffeine, 1,7-dimethylxanthine, cotinine, ibuprofen, sulfamethoxazole, triclosan, and trimethoprim. Removal of acetaminophen, cotinine and caffeine was greater than 99% and removal 1,7-dimethylxanthine, ibuprofen, and triclosan was greater than 90% using NAS and NTF treatment. Sulfamethoxazole and trimethoprim were inadequately removed in both NAS and NTF treatments. The horizontal, subsurface flow treatment wetland showed removals of 45-89% for sulfamethoxazole and greater than 96% for trimethoprim. There was no statistical difference (P>0.05) between aeration, temperature and vegetation in the treatment wetland for the removal of sulfamethoxazole and trimethoprim.
613

Middle Miocene to Holocene History of the Delacroix Island Fault System

Levesh, Jarrett Leigh 23 May 2019 (has links)
An in-depth field study of the Delacroix Island producing field illustrates the evolution of the east-trending Delacroix Island Fault during the last 13 My. Well log correlations and 3-D seismic interpretation of 22 subsurface bio-stratigraphic horizons across the fault reveal variable stratigraphic thicknesses and displacement. Wells, with well log curve data as shallow as 31 m (100 ft) below the surface, were used to calculate interval thicknesses, expansion indices, sediment accumulation rates, burial history and magnitudes of displacement. Through these analyses, a correlation was found between the positioning of ancient Miocene depocenters over Delacroix Island and a period of increased fault activity. Historic satellite imagery (last 34 yrs) of the field depicts a lineation on the modern marsh surface coincident with the upward projected fault plane. Continuous wetland loss on the downthrown side of the fault trace suggests that recent and continued fault movement may be contributing to marsh submergence.
614

DETERMINING TIDAL CHARACTERISTICS IN A RESTORED TIDAL WETLAND USING UNMANNED AERIAL VEHICLES AND DERIVED DATA

Thornton, Victor 01 January 2018 (has links)
Unmanned aerial vehicle (UAV) technology was used to determine tidal extent in Kimages Creek, a restored tidal wetland located in Charles City County, Virginia. A Sensefly eBee Real-Time Kinematic UAV equipped with the Sensor Optimized for Drone Applications (SODA) camera (20-megapixel RGB sensor) was flown during a single high and low tide event in Summer 2017. Collectively, over 1,300 images were captured and processed using Pix4D. Horizontal and vertical accuracy of models created using ground control points (GCP) ranged from 0.176 m to 0.363 m. The high tide elevation model was subtracted from the low tide using the ArcMap 10.5.1 raster calculator. The positive difference was displayed to show the portion of high tide that was above the low tide. These results show that UAVs offer numerous spatial and temporal advantages, but further research is needed to determine the best method of GCP placement in areas of similar forest structure.
615

Distribution and Drivers of a Widespread, Invasive Wetland Grass, Phragmites australis, in Great Salt Lake Wetlands

Long, Arin Lexine 01 May 2014 (has links)
Non-native invasive plant species can often have negative effects on native ecosystems, such as altered nutrient cycling, decreased habitat for wildlife, and outcompeting native plants. Around the Great Salt Lake (GSL), Utah, the invasive wetland grass Phragmites australis has become abundant in wetlands around the lake. Phragmites is replacing many native wetland plants provide important waterfowl habitat around the GSL. For successful management of Phragmites in GSL wetlands, it is important to know the current distribution of Phragmites, as well as areas that might be vulnerable to future invasion by Phragmites. To do this, we used multispectral aerial imagery to map the current distribution of Phragmites. We then created a model that statistically related the Phragmites distribution data to a suite of environmental predictor variables such as salinity, proximity to nutrient sources, or proximity to roads. Results from our model suggest that Phragmites is more likely to be found in wetland areas close to point sources of pollution, with lower elevations with prolonged inundation, and with moderate salinities. We used these results to identify areas around GSL that might be vulnerable to future invasion. Results from our study will assist wetlands managers in prioritizing areas for Phragmites monitoring and control by closely monitoring areas of prime Phragmites habitat.
616

Direct Effects of Warming Increase Woody Plant Abundance in a Subarctic Wetland

Carlson, Lindsay G. 01 December 2017 (has links)
Climate change is expected to continue to cause large increases in temperature in Arctic and sub-Arctic ecosystems which has already resulted in changes to plant communities; for example, increased shrub biomass and range. It is important to understand how warmer temperatures could affect the plant community in a wetland system because this region provides crucial high-quality forage for migratory herbivores during the breeding season. One mechanism by which warming could cause change is directly, where warming influences the vital rates of a species; these effects may be either positive or negative. Warmer temperatures may also affect a species indirectly, by impacting neighboring plants which compete with, or facilitate that species. Altering interspecific interactions may affect the abundances of the surrounding species. Recent research shows these ‘indirect’ effects which are mediated by biotic interactions may be important enough to reverse ‘direct’ effects of climate change in some plant communities. Furthermore, herbivores have been shown to mediate the effects of warming, in some systems, even preventing shrub expansion. However, the abundance of herbivores may change because of climate change so it is important to understand the role of herbivores in mitigating climate change effects to inform management strategy. Therefore, we aimed to determine the importance of direct and indirect effects of warming on this plant community while considering changing herbivore pressures. We conducted a two-year field experiment in the coastal wetlands of western Alaska to investigate how warming and herbivory will impact the abundances of two common species, a sedge and a dwarf shrub. We used the results from the experiment to predict the equilibrium abundances of the two species under different climate and herbivory scenarios and determine the contribution of direct and indirect effects to predicted community change. The sedge, Carex ramenskii, remained dominant in under ambient conditions, but the dwarf shrub, Salix ovalifolia, became dominant in warmed treatments. Herbivory mediated some of the effects of warming; where grazing was present community composition did not change as much as where it was not grazed. Results suggest that in the absence of goose herbivory, a 2°C increase could cause a shift from sedge to woody plant dominance on the coast of western Alaska. However, if grazing pressure by geese continues at the present rate, it may help retain the current community composition, though herbivory pressure was not sufficient to entirely reverse the effect of warming. Finally, we found that direct effects were more important than indirect effects in causing changes to this plant community.
617

Seasonal Transport of Suspended Solids and Nutrients Between Bear River and Bear Lake

Allen, Cody M. 01 December 2011 (has links)
Dingle Marsh is a wetland complex separating the Bear River from Bear Lake. Flow direction through the marsh is controlled at four major inflow and outflow sites. These sites were chosen as monitoring sites to assess the suspended solid and nutrient transport through the marsh. High frequency turbidity measurements were collected at each site and used as a surrogate for total phosphorus (TP) and total suspended solid (TSS) concentrations. Loads of TP and TSS were calculated using flow data from the 2008 water year. Load calculations for TP and TSS were compiled at 30-minute intervals and annual mass balances were calculated for Dingle Marsh and Bear Lake. These calculations were used to identify the seasonal loading patterns within this system. This study found the majority of TSS and TP loading entered the marsh from the Bear River. As flows moved across the marsh, the loading of TSS and TP was greatly reduced. Seasonal flow patterns were analyzed to determine the loading patterns to Dingle Marsh, Bear Lake, and the Bear River. This study also identified water management strategies aimed at setting a target endpoint for TSS and TP loads.
618

An assessment of the nutrient stripping function of two constructed wetlands in the Swan-Canning Estuary

Majimbi, Abbey Aggrey January 2007 (has links)
The use of constructed wetlands and wet detention basins has proven to be highly effective in removing pollutants from industrial discharges and stormwater runoff throughout the world. This is attributed to design of the key treatment components in a constructed wetland, catchment source characteristics and climatic conditions. A disproportionate amount of research and monitoring effort has gone into constructed wetlands due to their cost effectiveness and ability to optimize multiple benefits. In Western Australia, several wetland monitoring studies on the role of constructed wetlands especially in Swan-Canning estuary have been done, but often do not address their design efficiencies in stormwater treatment. Two wetlands (Liege St and Tom Bateman wetland) constructed for nutrient stripping proximal to the Swan-Canning estuary have been monitored for two years. Liege St wetland was constructed to reduce the nutrients reaching the Canning River directly and improve the amenity value of the area. Similarly, Tom Bateman wetland was constructed to reduce nutrients of the Banister Creek catchment draining into the Canning River as well as for stormwater management and habitat use. Physicochemical and biological indicators were used to assess the nutrient stripping efficiency of the wetlands. In some cases, data from previous studies were used to determine the health and viability of the selected wetland sites. The limnological indicators used included; dissolved oxygen, pH, water temperature, electrical conductivity and nutrient levels. The biological included; bacteria, nutrients and chlorophyll in periphyton, macroinvertebrates and diatoms. Differences in the community structure of periphyton, macroinvertebrates and water quality were found from the inlet to the outlet in both Liege St and Tom Bateman wetlands. / Despite the poor water quality, Liege St wetland exhibited significant nutrient removal efficiencies for TP while Tom Bateman wetland had very high removal efficiency for TN. The TP removal in Liege St wetland was attributed to the design of key treatment components which included a gross pollutant trap, concrete lined sedimentation pond, vegetated sumplands, weirs and clay lining for the wetland bed. In contrast, Tom Bateman wetland lacked the above key treatment components. Additionally, the wetland experienced short-circuiting especially during high flow periods. The high TN removal in Tom Bateman wetland was attributed to assimilation by plants and micro-organisms especially by the dense growth of Potamogeton crispus observed on the wetland floor and the non- biological transformation processes such as volatilisation, sorption and sedimentation. The poor water quality of the inflow in both wetlands was attributed to catchment characteristics which were not fully investigated in this study. In an attempt to improve the nutrient stripping function of Liege St and Tom Bateman wetland, changes to the wetland design and routine maintenance were suggested for Tom Bateman and Liege St wetland respectively. Also the use of the Swan-Canning Cleanup Programe (SCCP) water quality targets as opposed to the ANZECC trigger values in water quality assessments in constructed wetlands in the Swan-Canning estuary is suggested among others.
619

Spatial distribution of phosphorus in the sediments of a constructed wetland receiving treated sewage effluent

Rowley, Maxine Joy, University of Western Sydney, Hawkesbury, Faculty of Science and Technology January 1998 (has links)
The Byron Bay Sewage Treatment work consists of a conventional treatment system discharging into an 8 ha wetland. The wetland was constructed around the dune and swale remnants of a coastal beach ridge formation. The wetland design incorporated stands of broad leaf paperback, Melaleuca quinquenervia , in two distinct Sections, separated by, and each preceded by, open water Sections fringed by predominantly emergent macrophytes. Spatial and temporal patterns in sediment phosphorus concentrations were examined using sediment cores. Core consisted of three main sediment types - surface organic accumulation, pre-existing organic layers and sand. Results suggest that the design and management of wetland systems should be aimed at maximising the deposition of sediment (and associated phosphorus) and minimising subsequent phosphorus release from the sediment. This might be achieved through the removal of accumulated organic sediments to retain the phosphorus adsorption capacity of the system, consideration of wind direction during periods of high (floating) plant growth (as detritus may accumulate along the up-wind edges of the wetland), incorporation of deep zones to minimise sediment phosphorus release and the inclusion of stands of M. quinquenervia. Results highlight pitfalls in the prevailing approach to wetland design, which ignore the complex functions which occur in natural wetland systems. A more holistic approach incorporating a high diversity of ecozones in wetland design is proposed, in effect mimicking natural systems. / Master of Science (Hons)
620

Testing aquatic macroinvertebrate and plant techniques for the biological assessment of wetlands : a consideration of the effects of errors and implications for sampling design

Ling, Joanne Elizabeth, University of Western Sydney, College of Health and Science, School of Natural Sciences January 2006 (has links)
Rapid bioassessment techniques used for aquatic macroinvertebrate and plants in wetlands were tested in New South Wales, Australia. Wetlands surveyed ranged from coastal wetlands in the North and Central parts of the State, to tableland wetlands west of Sydney. Wetlands varied in dominant vegetation, hydrology, substrate and level of human impairment. Different options for sampling (mesh size, live-picking times, quadrat size, number of samples or quadrats) and analysis (taxonomic resolution, transformations, biotic indices, multivariate and univariate analyses) are compared to determine optimal sampling effort and evaluate the effects of errors or variability. Results show that, for wetlands of New South Wales, sampling procedures developed and tested in streams and other regions of Australia may not be the most efficient. Using the data from 21 wetlands in New South Wales, a number of analytical techniques were evaluated for the effects of errors. Results show that species-level multivariate analysis is more sensitive in detecting less obvious differences between wetlands (i.e., small effect sizes), while family-level analyses are more appropriate for large effect sizes. A modified waterplant index was developed that is simpler and has a wider application than the other Australian options available. Inherent problems in each index tested were addressed. The results show that the process of summarising a large amount of information into a single value will result in the loss of both information and variability between samples and this cumulative effect of error may effect the assessment of wetland condition. The practical outcome of this thesis is a set of standardised steps to assess wetland quality using biological assemblages. The results show that protocols and indices for rivers are not directly transferable to palustrine, vegetation dominated wetlands. I present protocols that are more appropriate to wetlands and recognise that each protocol would need to be adapted for each wetland type. Despite the need for flexible protocols, I promote the need for a standard approach to wetland sampling and the need for consideration of the effects of errors in sampling designs. This study highlights the need for more research on the response of specific stressors to wetlands flora and fauna. The results from this study also show that wetland macroinvertebrates and plant communities can be used as surrogates in multivariate analyses for detecting large differences between wetlands (wetland types) but that impact assessment requires more detailed investigations including species identification and careful consideration of the choice of reference and control sites. In conclusion I emphasise the need for scientific rigour in the use of biological indicators and consideration of the effects of errors and implications to sampling designs. / Doctor of Philosophy (PhD)

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