• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 445
  • 324
  • 36
  • 31
  • 25
  • 16
  • 16
  • 9
  • 7
  • 7
  • 6
  • 4
  • 3
  • 3
  • 2
  • Tagged with
  • 1108
  • 327
  • 158
  • 138
  • 116
  • 99
  • 92
  • 82
  • 82
  • 76
  • 76
  • 73
  • 71
  • 60
  • 59
  • 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.
501

Monitoramento e avaliação de sistema de tratamento para águas negras composto por reator UASB, fotobiorreator, flotação e processos de desinfecção / Monitoring and evaluation of treatment system for wastewater composed of UASB reactor, photobioreactor, flotation and disinfection processes

Nathalie Dyane Miranda Slompo 02 July 2018 (has links)
O modelo econômico extrair, transformar, descartar da atualidade está atingindo seus limites físicos. Confrontando-se com questões de disponibilidade de recursos A economia circular é uma alternativa atraente que busca redefinir a noção de crescimento, com foco em benefícios para toda a sociedade. Dentro dessa nova visão, conceitos de tratamentos descentralizados e sustentáveis de saneamento que concentram-se no tratamento e na reciclagem dos recursos presentes nas águas residuais domésticas são considerados. Assim, a partir de uma água residuária é possível obter três recursos principais: a bioenergia, nutrientes e água. Esta pesquisa teve por objetivo principal avaliar a produção de um efluente propício ao reúso não potável, a partir de água negra. A água negra foi tratada anaerobiamente (reator UASB) para remoção de matéria orgânica, seguindo para um fotobiorreator para remoção de nutrientes, com consequente separação da biomassa algal por flotação por ar dissolvido. Neste ponto foi avaliada a absorção de nutrientes pelas microalgas e o crescimento de sua biomassa. Após a flotação, o efluente foi desinfetado, avaliada assim, a inativação de coliformes totais e Escherichia coli, bem como de Giardia spp. e Cryptosporidium spp. no sistema de tratamento. O reator UASB manteve níveis elevados de remoção de matéria orgânica (DQO), com remoções de 70%. Apresentando uma média de remoção de Escherichia coli e coliformes fecais entre 1 e 3 log. Para protozoários essa remoção foi entre 0,5 e 1,5 log. O fotobiorreator, obteve satisfatório crescimento da biomassa, sem controle de temperaturas ou suplementação de CO2, apresentou também remoção/inativação de Escherichia coli e coliformes totais, com valores entre 0,50 a quase 3,0 log, apresentando de modo geral maior remoção/inativação para Escherichia coli. Foi observado remoção de protozoários e coliformes pela flotação por ar dissolvido, acarretando uma maior concentração destes na biomassa removida. O melhor desinfetante individual foi o cloro, em razão da inativação. No entanto, o ozônio foi o que melhor obteve remoção (oxidação) de matéria orgânica. Em relação aos desinfetantes aplicados de modo sequencial ou simultâneos, foi observado que a melhor inativação foi promovida pelo ensaio sequencial com ozônio e cloro, com inativação de até 3,10 e 3,38 log para Escherichia coli e coliformes totais, respectivamente. Com efeito sinérgico em relação a aplicação individual destes desinfetantes. Recomenda-se o uso do sistema para o tratamento descentralizado, principalmente em pequenas comunidades e em áreas rurais. / The current economic \"extract, transform, discard\" model is reaching its physical limits. Confronting with issues of resource availability Circular economics is an attractive alternative that seeks to redefine the notion of growth, with a focus on benefits for the whole society. Within this new vision, concepts of decentralized and sustainable sanitation treatments that focus on the treatment and recycling of resources present in domestic wastewater are considered. Thus, from a wastewater it is possible to obtain three main resources: bioenergy, nutrients and water. The main objective of this research was to evaluate the production of an effluent conducive to non-potable reuse from black water. The black water was treated anaerobically (UASB reactor) to remove organic matter, followed by a photobioreactor to remove nutrients, with consequent separation of the algal biomass by dissolved air flotation. At this point, the nutrient uptake by microalgae and the growth of their biomass were evaluated. After flotation, the effluent was disinfected, thus evaluating the inactivation of total coliforms and Escherichia coli, as well as Giardia spp. and Cryptosporidium spp. in the treatment system. The UASB reactor maintained high levels of organic matter removal (COD), with removals of 70%. Presents an average removal of Escherichia coli and faecal coliforms between 1 and 3 log. For protozoa this removal was between 0.5 and 1.5 log. The photobioreactor, obtained satisfactory biomass growth, without temperature control or CO2 supplementation, also showed removal/inactivation of Escherichia coli and total coliforms, with values ranging from 0.50 to almost 3.0 log, generally presenting greater removal inactivation for Escherichia coli. Removal of protozoa and coliforms by flotation by dissolved air was observed, leading to a higher concentration of these in the biomass removed. The best individual disinfectant was chlorine, due to inactivation. However, ozone was the one that best obtained removal (oxidation) of organic matter. Regarding disinfectants applied sequentially or simultaneously, it was observed that the best inactivation was promoted by the sequential test with ozone and chlorine, with inactivation of up to 3.10 and 3.38 log for Escherichia coli and total coliforms, respectively. With synergistic effect in relation to the individual application of these disinfectants. It is recommended to use the system for decentralized treatment, especially in small communities and in rural areas.
502

Tratamento e valorização de efluentes da bovinocultura por processos biológicos

Mendonça, Henrique Vieira de 08 March 2017 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-07-20T12:14:19Z No. of bitstreams: 1 henriquevieirademendonca.pdf: 2942439 bytes, checksum: adec0c99b1664979bc6b3d987df5ec32 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-09T12:29:52Z (GMT) No. of bitstreams: 1 henriquevieirademendonca.pdf: 2942439 bytes, checksum: adec0c99b1664979bc6b3d987df5ec32 (MD5) / Made available in DSpace on 2017-08-09T12:29:52Z (GMT). No. of bitstreams: 1 henriquevieirademendonca.pdf: 2942439 bytes, checksum: adec0c99b1664979bc6b3d987df5ec32 (MD5) Previous issue date: 2017-03-08 / Nesta pesquisa reatores e métodos biológicos foram testados para tratamento e valorização de águas residuais da bovinocultura. Um biodigestor plug flow seguido de lagoa de estabilização foram testados em escala real, temperatura ambiente e tempos de retenção hidráulica de 32 e 6 dias, respectivamente. Foram produzidos volumes de biogás entre 278,5 e 2186,1 m³ mês-1, com concentração média de CH4 de 65% que proporcionou geração mensal de energia entre 2.070 e 19.168 KWh, valores suficientes para suprir a demanda energética da fazenda. As remoções médias anuais de DBO5,20, DQO, NH4 e NTK foram de 86, 70, 88,5 e 85,5%, respectivamente. O efluente após lagoa foi utilizado como biofertilizante para cultivo de cana- de-açúcar (Saccharum officinarum). Foi verificado que a ureia pode ser substituída pelo biofertilizante como fonte de nitrogênio. Quando aplicado o biofertilizante foram atingidas produtividades acima de 147,5 Kg ha-1, valor superior à média Brasileira. Visando potencializar a produção de biogás, um reator anaeróbio híbrido foi testado em condições mesófilas (37°C ± 1ºC) e operado com tempos de retenção hidráulica de 6, 5, 3 e 2 dias. Concentrações de metano entre 69 e 75 % e volumes de biogás de até 1,4 m³ m-3 d-1 foram registrados, valor mais alto descrito pela literatura dos últimos 15 anos para este tipo de efluente. As remoções da matéria orgânica com valores de 60-81% (DQOt) e 51-75% (DQOs) proporcionaram a obtenção de rendimentos em metano de 0,155-0,183 m³ CH4 Kg-1 DQOt e 0,401-0,513 m³ CH4 Kg-1 DQOs. O efluente tratado pelo reator híbrido foi submetido a sedimentação em cone de Imhoff e encaminhado para tratamento secundário em fotobioreatores. Foram testados os métodos em bateladas e escoamento contínuo. Em regime de bateladas remoções de 65 a 70% de DQOs, 98 a 99% de NH4+ e 69 a 77,5% de PO4-3foram registradas em 12 dias. Em escoamento contínuo foram registradas remoções entre 57 e 61% de DQOs, 94 a 96% de NH4+ e 65 a 70% de PO4-3 com 12 dias de retenção hidráulica. Maiores produtividades volumétricas de biomassa da microalga Scenedesmus obliquus foram atingidas em regime de bateladas (213 - 358 mg L-1 d-1). A produtividade máxima de proteínas, carboidratos e lipídeos foram de 150, 110 e 64 mg L-1 d-1. O processo de biorremediação e valorização do efluente em fotobioreatores pode ser considerado promissor, podendo a biomassa ser utilizada não só como biofertilizante, mas também para suplementação na alimentação de ruminantes e ou para produção de biodiesel. / In this study, reactors and biological methods were tested for treatment and valorization of cattle wastewater. The waste was treated in real scale in a plug flow biodigestor followed by a stabilization pond, at ambient temperature and hydraulic retention times of 32 and 6 days, respectively. Biogas volumes between 278.5 and 2,186.1 m³ month-1 were produced, with average CH4 concentration of 65%, which enabled monthly electricity generation between 2,070 and 19,168 KWh, sufficient to supply the farm’s energy needs. The average annual removals of BOD5,20, COD, NH4 and TKN were 86, 70, 88.5 and 85.5%, respectively. The treated effluent from the pond was used as biofertilizer to grow sugarcane (Saccharum officinarum), and the results showed that this biofertilizer can replace urea as a source of nitrogen. With application of the biofertilizer, cane yields greater than 147.5 Kg ha-1 were attained, higher than the Brazilian average. Seeking to enhance the production of biogas, a hybrid anaerobic bioreactor was tested in mesophilic conditions (37 °C ± 1 ºC), operated with water retention times of 6, 5, 3 and 2 days. Methane concentrations between 69 and 75% and biogas volumes up to 1.4 m³ m-3 d-1 were obtained, the last value being higher than described in the literature over the past 15 years for this type of effluent. The removals of organic matter, with values of 60-81% (CODt) and 51-75% (CODs), allowed obtaining methane yields of 0.155-0.183 m³ CH4 Kg-1 CODt and 0.401-0.513 m³ CH4 Kg-1 CODs. The effluent treated in the hybrid reactor was submitted to sedimentation in an Imhoff cone and then sent for secondary treatment in photobioreactors, applying both batch and continuous flow methods. In the batch regime, removals of 65 to 70% of CODs, 98 to 99% of NH4+ and 69 to 77.5% of PO4-3 were recorded after 12 days. In continuous flow mode, the removals were 57 to 61% of CODs, 94 to 96% of NH4+ and 65 to 70% of PO4-3 with hydraulic retention time of 12 days. Higher volume yields of biomass of the microalga Scenedesmus obliquus were achieved in batch operation (213 - 358 mg L-1 d-1). The maximum productivity of proteins, carbohydrates and lipids were 150, 110 and 64 mg L-1 d-1. The process of bioremediation and valorization of cattle wastewater in photobioreactors can be considered promising, since besides energy generation, the biomass can be used as fertilizer, feed for ruminants and/or production of biodiesel.
503

Carnivoria e suas consequências ecológicas em Philcoxia minensis V. C. Souza & Giulietti (Plantaginaceae) / Carnivory and its ecological consequences in Philcoxia minensis V. C. Souza & Giulietti (Plantaginaceae)

Guilherme Pereira, Caio, 1988- 23 August 2018 (has links)
Orientador: Rafael Silva Oliveira / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T00:25:50Z (GMT). No. of bitstreams: 1 GuilhermePereira_Caio_M.pdf: 4423463 bytes, checksum: b3d0cccfd6c5f84a9df0f479651580a0 (MD5) Previous issue date: 2013 / Resumo: Plantas carnívoras são aquelas que apresentam a capacidade de capturar e digerir pequenos animais, geralmente invertebrados. Os estudos com essas plantas começaram há mais de um século e, ainda hoje, não são conhecidos os mecanismos que determinaram a evolução e a distribuição geográfica dessas singularidades vegetais. Os modelos de custos--benefícios vêm, nesse sentido, atuando como guias para diversos estudos nas últimas décadas e parecem esclarecer diversos pontos obscuros quanto à ecologia e evolução dessas plantas. O gênero Philcoxia (Plantaginaceae), endêmico de campos rupestres -- ambientes associados a afloramentos rochosos e a formações de areia branca, propensos a eventuais queimadas e pobres em nutrientes --, apresenta características que acabaram por levar a questionamentos quanto à sua fisiologia. Com o acúmulo crescente de evidências, estudiosos começaram a sugerir que tais espécies pudessem apresentar mecanismos ativos de captura e digestão de presas. O estudo em questão teve como objetivo determinar se Philcoxia minensis exibe a síndrome da carnivoria e analisar os custos e benefícios desse hábito no contexto teórico sugerido por Thomas J. Givnish para a evolução da carnivoria. Para isso, fizemos uma detalhada descrição anatômica das folhas de P. minensis, na qual pudemos observar padrões evidentes de produção enzimática associada à digestão de invertebrados, em especial de fosfatases. Caracterizamos as estruturas glandulares responsáveis pela produção dessas enzimas, assim como os nematódeos que são considerados, até o momento, as únicas presas de P. minensis. Por fim, quanto à absorção de nutrientes derivados dos nematódeos, pudemos observar uma incorporação de 5% do nitrogênio das presas (Caenorhabditis elegans) em apenas 24h, e 15% em 48h em um experimento com isótopos estáveis. Para avaliar o balanço energético dessa espécie, analisamos de que forma características foliares associadas aos processos de fotossíntese e respiração se correlacionam. De maneira geral, encontramos forte correlação entre as capacidades fotossintéticas (Aarea e Amass) e os valores de LMA (quantidade de massa seca por unidade de área foliar) para as espécies não carnívoras, com um claro distanciamento dos indivíduos de P. minensis, que apresentaram taxas fotossintéticas extremamente baixas. Quanto às correlações entre os conteúdos de nitrogênio e de fósforo com as capacidades fotossintéticas, vimos que os indivíduos de P. minensis apresentaram taxas fotossintéticas extremamente baixas para os valores desses dois nutrientes e, embora uma tendência possa ser observada, não observamos correlações entre capacidades fotossintéticas e os conteúdos foliares de nitrogênio e fósforo. Por fim, conseguimos determinar conclusivamente a natureza carnívora de P. minensis, assim como pudemos posicionar essa espécie ao longo do espectro de economia foliar, tanto de forma local quanto em uma escala global. Nossos resultados ilustram o quanto ainda há para ser descoberto quanto à origem, à distribuição e à frequência da síndrome da carnivoria / Abstract: Carnivorous plants are plants that have the ability to capture and digest small animals, usually insects and other invertebrates. The studies with these plants began in the nineteenth century and until today it is unknown the underlying mechanisms that determine the evolution and the geographical distribution of these singularities. The cost--benefit models are, accordingly, acting as guidelines to various studies in recent decades and seem to be able to clarify many obscure points concerning the ecology and the evolution of these plants. The three species of the genus Philcoxia, endemic to campos rupestres -- fire prone and nutrient--poor environments usually associated with rocky outcrops and white sand formations -- have unique characteristics and adaptations that eventually led to several questions regarding the physiology of these plants. With growing accumulation of evidence, scholars started to consider the possibility that such plants could present active mechanisms for capturing and digesting prey. The present study aimed to determine if Philcoxia minensis exhibits the syndrome of carnivory and to analyze the costs and benefits of this habit in the theoretical context suggested by Thomas J. Givnish for the evolution of carnivory. In order to do so, we have made a detailed anatomical description of the leaves of P. minensis, in which we observed a clear pattern of enzyme production possibly associated with prey digestion, including phosphatases. We also characterized the glandular structures that are responsible for the production of the enzymes as well as the nematodes that are considered, until now, the only prey of P. minensis. Concerning the absorption of nutrients derived from prey, we observed an incorporation of 5% of the nitrogen of the nematodes (Caenorhabditis elegans) in 24h, and 15% in 48h in an experiment with stable isotopes. To evaluate the energy balance of this species, we analyzed correlations between leaf traits associated with the processes of photosynthesis and respiration. Generally speaking, we found a strong correlation between the photosynthetic capacity (Amass and Aarea) and the LMA (leaf mass per area) values for neighboring non--?carnivorous plants, with a distancing of P. minensis individuals, which showed very low photosynthetic rates. Regarding the correlations between the contents of nitrogen and phosphorus with photosynthetic capacities, we observed that the individuals of P. minensis showed extremely low photosynthetic rates for their nutrient concentrations and, although a tendency could be observed, there is no correlation between photosynthetic capacity and the foliar contents of nitrogen and phosphorus. Finally, we have conclusively determined the carnivorous nature of P. minensis and we placed this species along the leaf economics spectrum, both in local and global scale. Our results illustrate how much there is still to be discovered about the origin, distribution and frequency of the carnivorous syndrome / Mestrado / Ecologia / Mestre em Ecologia
504

Potencial de poluição de aguas superficiais por fontes não pontuais de fosforo na Bacia hidrografica do Ribeirão do Pinhal, Limeira- SP

Mansor, Maria Teresa Castilho 03 November 2005 (has links)
Orientadores: Denis Miguel Roston, Jose Teixeira Filho / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-04T08:27:27Z (GMT). No. of bitstreams: 1 Mansor_MariaTeresaCastilho_D.pdf: 2529546 bytes, checksum: 5e7bcdd25d9104de1649f7fade2168ac (MD5) Previous issue date: 2005 / Resumo: Em áreas rurais onde há intensa atividade agrícola, a eutrofização de corpos de água pode ser acelerada pelo influxo de nutrientes, provenientes de fertilizantes, transportados por escoamento superficial. A eutrofização pode provocar mudanças indesejáveis na estrutura e funções do ecossistema, bem como na qualidade da água destinada ao abastecimento. O controle dos níveis de P nas águas superficiais é tido como a melhor maneira de minimizar a eutrofização, uma vez que o P é identificado como um nutriente limitante para o crescimento de algas. As águas da bacia do rio Piracicaba recebem grande aporte de efluentes domésticos e industriais pontuais, bem como grande aporte de efluentes agrícolas difusos, tendo sido documentado aí um elevado grau de eutrofização. Uma avaliação preliminar das contribuições difusas de nutrientes às águas superficiais da bacia hidrográfica do rio Jaguari - formador do rio Piracicaba - feita a partir de dados oficiais em uma área de estudo de 3394 Km2, mostrou que 68,2% da carga total anual de Ntotal e 77,3% da carga total anual de Ptotal foram transportados nos meses de chuva. Ao se estimar a razão entre a carga média anual de origem rural (difusa) e urbana (pontual), obteve-se o valor de 1,3 para o Ntotal e 2,6 para o Ptotal; os coeficientes de exportação a partir da área rural foram estimados em 2,3 Kg Ntotal.ha-I.ano-l e 0,4 Kg Ptotal.ha-l.ano-l. A área de drenagem da bacia do ribeirão do Pinhal - afluente do rio Jaguari e manancial de abastecimento de Limeira, SP - foi o foco principal deste estudo, ocorrido entre fevereiro de 2003 e fevereiro de 2004. Estimou-se, para uma área de 301,4 Km2 de ocupação majoritariamente agrícola, a quantidade de P aplicada ao solo como fertilizante, obtendo-se um total de 820 ton.anoo1, dos quais inferiu-se que 23% foram exportados pela biomassa. Monitorou-se, no mesmo período, as concentrações de Ptotal e SStotais em cinco pontos da bacia do ribeirão do Pinhal, objetivando a estimativa de fluxos. As cargas anuais de Ptotal e SStotais obtidas na entrada do reservatório do Tatu foram iguais a 5,7 e 2160 ton.ano-I, respectivamente, sendo que 67,5% do Ptotal e 84,5% dos SStotais foram transportados no período chuvoso. Os coeficientes de exportação obtidos na entrada do reservatório foram iguais a 0,2 KgPtotal.haol.anool e 7,4 tonSStotaiS.Km-2.ano-l. Ao se inferir sobre as cargas difusas de Ptotal transportadas por escoamento superficial pelo ribeirão do Pinhal, obteve-se uma razão de 0,6 entre a carga anual de origem difusa e aquela pontual, apontando a importância desta última na bacia. Por fim, fez-se um levantamento limnológico do reservatório do Tatu, e observou-se que o IET referente ao Ptotal e à clorofila a indicou estado eutrófico na cabeceira e barragem; entretanto, é provável que a alta taxa de descarga esteja limitando a proliferação de algas no reservatório. De modo geral, verificou-se preliminarmente a importância da poluição difusa de Ptotab de origem rural, na degradação das águas superficiais da bacia do rio Jaguari. Por outro lado, focando na bacia do ribeirão do Pinhal, concluiu-se que as altas concentrações de Ptotal aí obtidas foram influenciadas pela atividade industrial e ocupação humana, influência esta que se sobrepôs àquela do arraste de partículas causado pelo escoamento superficial decorrente das precipitações / Abstract: Intensive agricultural activities are known to cause anthropogenic inputs ofnutrients to surface waters in rural areas. The nutrient enrichment of water bodies, or eutrophication, can lead to highly undesirable changes in ecosystem structure and function, as well as in water quality for human consumption. It is known that nutrient loading restriction - specially the limiting nutrient phosphorus - is the essential comerstone of aquatic eutrophication controI. In a preliminary study, official water quality and flow data from Jaguari River were used to assess the diffuse loads of nutrients from rural areas into surface waters. Results showed that, in average, 68.2% of the TN annualloads and 77.3% of the TP annualloads were transported through a 3394 Km2 area during the raining season. The annual diffuse loads obtained coming primarily from rural sources - were equivalent to 55.1% and 69.4% ofthe total annual loads of TN and TP transported through the sub-basin, respectively. The mean export coefficients from diffuse loads were equal to 2.3 Kg TN.ha-1.year-1 and 0.4 Kg TP.ha-'.year-1. The main part of this study was realized at the Ribeirão do Pinhal - a Jaguari River affluent from February 2003 to February 2004. The annual phosphorus load applied as fertilizer to an area of301.4 Km2 ofthe ribeirão do Pinhal watershed was estimated to be 820 ton.year-', and 23% of it was calculated to be exported by the biomass of the agricultural fields. These results were based on the soil use and occupation of the area, mainly rural, producing basically sugarcane and citrus. The field sampling of Ribeirão do Pinhal superficial waters was done twice a month, in five locations at the watershed. Samples were analyzed for TP and TSS; the totalloads obtained were equal to 5.7 e 2160 ton.year-', respectively, at the entrance ofTatu reservoir; 67.5% of TP and 84.5% of TSS were transported during the raining season (October-March). The export coefficients obtained were equal to 7.4 ton TSS.Km-2.year-1 and 0.2 Kg TP.ha-1.year"'. A limnological profile of the Tatu reservoir was determined through field sampling in three locations on both dry and wet periods; results showed a eutrophic state at the entrance of the reservoir as well as at the damo Yet, the flushing rate is the possible limiting factor for the occurrence of eutrophication at the reservoir. In general, the importance of diffuse pollution, originally from rural areas, was verified at the Jaguari River watershed. On the other hand, at the Ribeirão do Pinhal watershed, the high TP concentrations observed were most1y influenced by the industrial and human activities occurring in the area / Doutorado / Agua e Solo / Doutor em Engenharia Agrícola
505

Nutrients and runoff in a small catchment during spring 2010

Skoog, Peter, Bodin-Sköld, Henrik January 2010 (has links)
Eutrophication is an increasing problem in the Baltic Sea and is caused by an excess of nutrients in the water which are primarily transported with the runoff from cultivated land. The peninsula Vikbolandet in Östergötland is dominated by arable land and has stream outflows to the bays of Bråviken and Slätbaken. In this study five streams of Vikbolandet have been sampled during the spring flood period with the aim of connecting concentrations of nutrients in the streams with turbidity and runoff in the catchment. This analysis has then been related to the land use in the small catchment of Vadsbäcken in order to investigate the impact of land uses with areal losses of phosphorus. The results indicate that there are increasing concentrations of phosphorus downstream in the sites of Vadsbäcken and that the transported amounts of phosphorus increases with the spring flood and at a rainstorm event. It is shown that the distribution of agricultural blocks in the catchment of Vadsbäcken has a major impact on the nutrient leakage. There is a co-variation between turbidity and runoff during a rainstorm event and between particulate-bound phosphorus and runoff over time. A further aim has been to investigate possibilities for use of an easily managed, cost-effective environmental monitoring method for nutrient measurements in watercourses. Within four out of five streams at Vikbolandet there is a significant co-variation between turbidity and total phosphorus. Using field measurements of turbidity for environmental monitoring could provide a viable alternative for environmental monitoring of watercourses but will need further investigations of co-variation before being brought into use. Further, this study shows that the transport of phosphorus is underestimated in environmental monitoring
506

Comparing C, N and P concentrations in soils in agricultural verus natural land, and across climates

Classon, Agnes January 2016 (has links)
How do concentrations of C, N and P vary between agricultural and natural land?How do C, N and P concentrations vary between climate zones? Soil organic carbon (SOC),total nitrogen (TN) and phosphorus (TP) as well as microbial C, N and P (MBC, MBN andMBP respectively) concentrations in soils were collected through a literature review, andstudied to analyze the differences between agricultural land-use and natural land, and betweendifferent climate zones. The minimum concentrations of SOC, TN, MBC, MBN and MBP werefound in the agricultural soils and the maximum concentrations in natural soils. The minimumTP concentration was the same for the two land types but the maximum concentration wasfound in agricultural soils. The mean concentrations of MBC, MBN, MBP, SOC and TN weresignificantly lower in the agricultural land than in the natural land.The highest concentrations of soil and microbial C, N and P were found in the tropical wetclimate, in the highlands, in the midlatitude climate with high temperature variations, and in themarine west coast climate. The results show that: 1. rainfall and mild to warm temperaturescould increase nutrient concentrations; 2. northern latitudes and highlands have high stocks ofnutrients, and 3: Humid subtropical climates are probably more exploited to humans due toagricultural productivity which decreases nutrient concentrations.The results clearly show the loss of nutrients following cultivation, and the importance ofresearch of nutrient status in soils; for global soil and water quality issues, for a sustainableagricultural production and for ecosystems.
507

ESTUDO DA DISTRIBUIÇÃO DE POLUENTES EM SUPERFÍCIES URBANAS / STUDY OF POLLUTANT DISTRIBUTION IN URBAN SURFACE

Silva, Ana Roberta Victoria 27 February 2009 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / This paper aimed to quantify pollutants connected to sediments of different sizes in impermeable surfaces in three sampling campaigns. Dry sediments collections were dane on Marquês do Herval ad Rigoberto Duarte streets, both located on the Cancela Creek basin in Santa Maria county, RS, as well as hidrosedimental monitoring at the drainage system escape on Marquês do Herval St. Dry sediments samples prior to rainfall, as well as surface runoff sediment samples during rainfall, were separated into 4 granulometric bands (≤63μm, 63-250μm, 250-500μm e ≥500μm). Organic pollution, nutrient and heavy metal contents were evaluated for each granulometric band by determining the concentration of the following parameters: oxygen chemical demand, ammonia, nitrite, nitrate, phosphate, sulphate, chloride, fluoride, copper, nickel, zinc and lead. Granulometry lower than 63μm represented on average 2,6% of the total sediment content for Marquês do Herval St. and 3,5% for Rigoberto Duarte St. Granulometry above 250μm represented on average 70% of the sediment content for both streets. Heavy metal samples showed higher concentrations in granulometry below 63μm. In dry sediment samples, the highest sulphate, phosphate and chloride contents were found in granulometry above 500μm. Ammmonia, nitrate, lead and zinc are associated with the 63-250μm granulometric band. / Este trabalho teve como objetivo quantificar os poluentes ligados aos diversos tamanhos de sedimentos em superfícies impermeáveis em três campanhas de amostragem. Foram realizadas coletas de sedimento seco nas ruas Marquês do Herval e Rigoberto Duarte, ambas localizadas na bacia do arroio Cancela no município de Santa Maria-RS; e monitoramento hidrossedimentológico na saída da canalização da rua Marquês do Herval. As amostras de sedimento seco dos dias anteriores a precipitação, bem como as de sedimento ligado ao escoamento superficial, durante a precipitação, foram separadas em 4 faixas granulométricas (≤63μm, 63-250μm, 250-500μm e ≥500μm). Para cada faixa granulométrica foi avaliada a carga de poluição orgânica, de nutrientes e de metais pesados, através da determinação das concentrações dos seguintes parâmetros: demanda química de oxigênio, amônia, nitrito, nitrato, fosfato, sulfato, cloreto, fluoreto, cobre, níquel, zinco e chumbo. A granulometria menor que 63μm representa em média 2,6% da carga total de sedimentos para a rua Marquês do Herval e 3,5% para a rua Rigoberto Duarte. A granulometria maior que 250μm representa em média 70% da carga de sedimentos em ambas as ruas. As amostras de metais pesados apresentaram maiores concentrações na granulometria menor que 63Sm. Nas amostras de sedimento seco, as maiores cargas de DQO, sulfato, fosfato e cloreto foram encontradas na granulometria maior que 500μm. A amônia e o nitrato, chumbo e zinco estão associados a faixa granulométrica de 63-250μm.
508

The Fate of Fecal Indicator Bacteria in Passive Nitrogen Reduction Systems

Henderson, Michelle B. 14 July 2017 (has links)
The sustainability of water resources is an international and national concern. With increased human activity, water distribution on a global, regional, and local scale has been negatively impacted. Managing water resources also includes managing wastewater. A promising solution to the issues of water scarcity and distribution in the environment is the reuse of wastewater. Wastewater is produced from various sources (domestic, industrial, and commercial); however, if this water is able to be reused closer to the source of generation it could positively impact water distribution. In the United States, approximately 25% of domestic wastewater is treated in onsite wastewater treatment systems OWTS (mainly septic tanks and drainfields). However, septic systems are not efficient at removing nitrogen and pathogens, making them a risk to public health and the environment. In recent years, advanced onsite wastewater treatment systems have been developed to reduce contaminants into the environment. These systems are effective at removing contaminants but often require many mechanical parts and have high energy requirements. These additional components require homeowners to perform more maintenance on advanced OWTS than conventional systems or pay for maintenance to be performed. Passive Nitrogen Reduction Systems (PNRS) are being developed that provide high levels of nutrient removal while keeping maintenance requirements and costs low for the homeowner. (PNRS) use two-stage packed bed bioreactors to remove nitrogen from wastewater via nitrification (Stage I) and denitrification (Stage II). Our laboratory has developed a two-stage bench scale PNRS that uses ion exchange (IX) materials, clinoptilolite and scrap tire chips, to enhance the removal of nitrogen from wastewater by buffering transient loads to the biological processes. Pathogens can be present in domestic wastewater and if untreated can be released to groundwater and open water bodies endangering the health of the public. PNRS have the potential to reduce pathogenic microorganism released into the environment, however; the reduction of pathogens in PNRS that include IX media had not previously been studied. In this research, E. coli was used as a fecal indicator bacteria (FIB) because of its simplicity and national and worldwide acceptance. In our study, the performance of a PNRS with and without IX media was evaluated. Hourly studies were performed to determine the removal efficiency of E. coli from the system under varying hydraulic loading rates. Biofilm detachment experiments were conducted to measure E. coli adsorption and growth patterns within the column reactors. Batch adsorption experiments were completed to determine the effect of different types of media with and without IX material on E. coli growth over extended time periods. E. coli enumeration data from the hourly experiments demonstrated that there was a 0.84 log reduction of E. coli throughout the PNRS from the septic tank effluent to the final effluent released from the system. The evening and afternoon periods showed a higher reduction of E. coli compared with the morning period. Removal efficiencies were greater in the first stage of treatment (nitrification) as compared to the second stage treatment (denitrification). However, these variances did not result in significant differences in overall E. coli removal efficiency. Adsorbed E. coli were evenly distributed in the column containing IX media, while a decrease in adsorbed E. coli with depth was observed in the column without IX media. Batch adsorption studies revealed that when E. coli are present in wastewater solution with media, E. coli are initially adsorbed but can grow in the system after 6-12 hours. This growth indicates that other FIB should also be used to determine the fate of pathogens in PNRS. Based on all E. coli enumeration experiments, the PNRS developed reduce E. coli by almost 85%; however, this reduction is not adequate to meet onsite water reclamation regulations. Further studies are needed to develop tertiary treatment for pathogen reduction and wastewater reuse.
509

Managing erosion, sediment transport and water quality in drained peatland catchments

Marttila, H. (Hannu) 04 January 2011 (has links)
Abstract Peatland drainage changes catchment conditions and increases the transport of suspended solids (SS) and nutrients. New knowledge and management methods are needed to reduce SS loading from these areas. This thesis examines sediment delivery and erosion processes in a number of peatland drainage areas and catchments in order to determine the effects of drainage on sediment and erosion dynamics and mechanics. Results from studies performed in peat mining, peatland forestry and disturbed headwater catchments in Finland are presented and potential sediment load management methods are discussed for drainage areas and headwater brooks. Particular attention is devoted to erosion of organic peat, sediment transport and methods to reduce the impacts of peatland drainage in boreal headwaters. This thesis consists of six articles. The first and second papers focus on the erosion and sediment transport processes at peat harvesting and peatland forestry drainage networks. The results indicate that in-channel processes are important in drained peatland, since the drainage network often constitutes temporary inter-storm storage for eroding and transporting material. Sediment properties determine the bed sediment erosion sensitivity, as fluffy organic peat sediment consolidates over time. As flashiness and peak runoff control sediment entrainment and transport from drained peatland areas, water quality management should include peak runoff management. The third, fourth and fifth papers studies use and application of peak runoff control (PRC) method to the peat harvesting and peatland forestry conditions for water protection. Results indicate that effective water quality management in drained peatland areas can be achieved using this method. Installation of the PRC structures is a useful and cost-effective way of storing storm runoff waters temporarily in the ditch system and providing a retention time for eroded sediment to settle to the ditch bed and drainage network. The main effect of the PRC is on SS and SS-bound nutrients. The sixth paper is concentrated to test new restoration structure to be used in degraded headwater brooks. The results show that addition of woody restoration structures to the channel is effective and simple sediment management methods in headwater areas. New information provided in this thesis on sediment erosion and transport processes in drained peatland areas can help to improve water quality control in these areas. In-channel processes are important for both peatland uses, since the drainage network often constitutes temporary inter-storm storage for eroding and transporting material. Therefore, controlling these processes is a key to effective water quality management, which can be achieved using the PRC method in drainage areas or by utilisation of natural fluvial processes in natural channels downstream.
510

Phytoplankton drivers in a marine system influenced by allochthonous organic matter – the Baltic Sea

Paczkowska, Joanna January 2016 (has links)
Climate change scenarios predict that seawater temperature and precipitation will increase in the Baltic Sea region during the next century. In the northern part of the Baltic Sea, increasing inflows of the terrestrial allochthonous dissolved organic matter (ADOM) are expected to be a major consequence of elevated rainfall, which can alter light and nutrient availability for phytoplankton. The aim of my thesis was to elucidate effects of ADOM on phytoplankton production, community, size-structure and nutritional strategy along offshore south-north gradients in the Baltic Sea, as well as in estuarine systems exposed to seasonal variation in river discharge. Field studies, a mesocosm experiment and a modeling study were used to explore these issues. Results from the field studies and mesocosm experiment illustrated that the nutritional strategy, size-structure and cellular pigment content of the phytoplankton were governed by changes in ADOM, and thus in light and nutrient availability. A summer study along an offshore south-north gradient showed that the proportion of mixotrophic phytoplankton increased towards the north. In this area the concentrations humic substances (proxy for ADOM) were high, while the light availability and phosphorus concentrations were relatively low. The phytoplankton cells responded to reduced light availability by increasing their chlorophyll a: carbon ratio. Additionally, the levels of photoprotective pigments decreased from south to north, as a result of acclimation to a low-light environment and reduced exposure to ultraviolet radiation. According to ecological assumptions picophytoplankton should be favored in light- and nutrient-limited environments. However, the results did not follow that pattern, the proportion of picophytoplankton being highest in the relatively nutrient rich Baltic Proper. The study was performed during the decline of an extensive bloom of filamentous cyanobacteria, a successional phase in which picophytoplankton often dominate the phytoplankton community. The estuarine studies performed in the Bothnian Bay (Råne estuary) and in the Bothnian Sea (Öre estuary) showed different successions. In the Råne estuary no spring phytoplankton bloom occurred and highest primary production was observed during the summer. This absence of a spring bloom was explained by low phosphorus and high ADOM concentrations, while the summer maximum could be explained by higher temperature and nutrient concentrations. In the Öre estuary a marked phytoplankton spring bloom was observed as well as an ADOM sustained bacterial production phase. The later secondary peak of bacterial production observed in summer, concomitant with an extended secondary primary production peak, suggests that autochthonous dissolved organic matter supported the bacterial growth Furthermore, the photosynthetic efficiency (i.e. phytoplankton growth rates) was lower during spring, indicating that high ADOM, and thus lower light and phosphorus availability, disfavored phytoplankton growth. Our modeling study showed that climate change can impact the food web; however effects will be different between basins. In the southern Baltic Sea elevated temperature and nutrient discharge may promote nutrient recycling and oxygen consumption, potentially extending anoxic areas, sediment nutrient release and cyanobacteria blooms. In the north, increased inflow of ADOM may promote heterotrophic bacterial production and decrease primary production due to light attenuation and lower phosphorus availability. This will favor the heterotrophic microbial food web and consequently lead to lower food web efficiency of the ecosystem.

Page generated in 0.0973 seconds