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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.
11

Decomposição de macrófitas aquáticas em dois reservatórios com diferentes estados tróficos

Rocha, Rinaldo José da Silva 23 May 2012 (has links)
Made available in DSpace on 2016-06-02T19:32:04Z (GMT). No. of bitstreams: 1 4733.pdf: 3640369 bytes, checksum: 241bde399e7bf5d34363759fa6ab1025 (MD5) Previous issue date: 2012-05-23 / Financiadora de Estudos e Projetos / The macrophytes are essential for the development and maintenance of food webs, to carbon dynamics and nutrient cycling in tropical aquatic systems. After senescence and plant death, decomposition of organic detritus depends heavily on their elemental compositions. Thus, the present study aimed to evaluate the effect of seasonality and trophic state of reservoirs and Vigário Lajes on the mass losses of detritus of Salvinia auriculata, Pistia stratiotes, Eichhornia crassipes, Sagittaria montevidensis and Brachiaria subquadripara, the influence of elemental composition of debris on the coefficients decay of carbon, nitrogen and phosphorus, and the stoichiometric ratios between these elements during the decomposition process. Over 120 days, the richest detritus in nutrients and less refractory (S. montevidensis and P. stratiotes) showed a biphasic pattern of decay and the greater decay of carbon (70-90%), phosphorus (90-96%) and nitrogen (68-94%). The poorest and refractories detritus (S. auriculata and E. crassipes) had lower rates of decay, with monophasic and biphasic patterns and lower mass loss in carbon-based (20-34%), phosphorus-based (26%), and nitrogen-based (10- 37%). As for the difference between the environments, the total mass loss of carbon was up to 70% higher during the rainy season (Sept/10 to Jan/11) and 27% higher in the dry season (may/11 to Sep/11) for detritus S. auriculata incubated in the reservoir Vigário; for the detritus of B. subquadripara total mass loss was also greater in this reservoir, reaching 58% in the rainy season and 36% during the dry season. The minor differences between the environments occurred in the mass loss of carbon detritus of S. montevidensis, (ca. 1.3% and 0.3% in rainfall in the dry season) and P. stratiotes (ca. 5.3% in the rainy season and 5.5% in the dry season). Yet these detritus showed the greatest losses of phosphorus (90-95%) and nitrogen (68-94%) in both experiments. The minor differences between the environments occurred in the mass loss of carbon detritus of S. montevidensis, (ca. 1.3% and 0.3% in the rainy season in the dry season) and P. stratiotes (ca. 5.3% and 5.5% in the rainy season in the dry season). Yet these detritus showed the greatest losses of phosphorus (90-95%) and nitrogen (68-94%) in both experiments. The ratio between carbon and nitrogen was higher in detritus of S. auriculata and E. crassipes in oligotrophic reservoir, and lower in detritus of S. montevidensis and P. stratiotes, whose mass loss coefficients (k) were higher. / As macrófitas são essenciais para o desenvolvimento e manutenção das cadeias tróficas, para a dinâmica do carbono e ciclagem de nutrientes de sistemas aquáticos tropicais. Após senescência e morte das plantas, a decomposição dos detritos orgânicos depende muito das suas composições elementares. A temperatura, a concentração de nutrientes inorgânicos no meio, as relações estequiométricas entre os organismos decompositores e os detritos podem afetar as taxas de decomposição, embora no caso da relação estequiométrica isso nem sempre ocorra. Nesse sentido, esse estudo teve como objetivo avaliar o efeito da sazonalidade e da condição de trofia dos reservatórios de Lajes e de Vigário sobre as perdas de massa dos detritos de Salvinia auriculata, Pistia stratiotes, Eichhornia crassipes, Sagittaria montevidensis e Brachiaria subquadripara; a influência da composição elementar dos detritos sobre os coeficientes de decaimento de carbono, nitrogênio e fósforo; e as relações estequiométricas entre esses elementos durante o processo de decomposição. Ao longo de 120 dias, os detritos mais ricos em nutrientes e menos refratários (S. montevidensis e P. stratiotes) apresentaram padrão bifásico de decaimento, além dos maiores decaimentos de carbono (70 a 90%), fósforo (90 a 96%) e nitrogênio (68 a 94%). Os detritos mais pobres e refratários (S. auriculata e E. crassipes) apresentaram menores coeficientes de decaimento, com padrões monofásico e bifásico e as menores perdas de massa em base de carbono (20 a 34%), de fósforo (26%) e de nitrogênio (10 a 37%). Quanto à diferença entre os ambientes, a perda de massa total de carbono foi até 70% maior no período das chuvas (set/10 a jan/11) e 27% maior no período seco (mai/11 a set/11) para detritos de S. auriculata incubados no reservatório de Vigário; para os detritos de B. subquadripara a perda de massa total também foi maior neste reservatório, chegando a 58% no período das chuvas e 36% no período seco. As menores diferenças entre os ambientes ocorreram na perda de massa de carbono dos detritos de S. montevidensis , (ca. 1,3% nas chuvas e 0,3% na seca) e de P. stratiotes (ca. 5,3% nas chuvas e 5,5% na seca) .Contudo, esses detritos apresentaram as maiores perdas de fósforo (90 a 95%) e de nitrogênio (68 a 94%) nos dois experimentos. A razão entre carbono e nitrogênio foi mais alta nos detritos de S. auriculata e E. crassipes, no ambiente oligotrófico, e mais baixa nos detritos de S. montevidensis e P. stratiotes, cujos coeficientes de perda de massa (k) foram maiores.
12

Bioacumulação de íons de Pb+² na macrófita Salvinia auriculata / Of the lead ions bioaccumulation process by living aquatic macrophytes Salvinia auriculata

Thomé, Luciara Ciane Port 13 February 2008 (has links)
Made available in DSpace on 2017-07-10T18:08:07Z (GMT). No. of bitstreams: 1 Luciara Ciane Port Thome.pdf: 1696527 bytes, checksum: f809752851373066f0420949b0b14357 (MD5) Previous issue date: 2008-02-13 / In this work was carried out a study of the lead bioaccumulation process by living aquatic macrophytes Salvinia auriculata. Initially, they were performed toxicological and growing tests in order to determine the non-toxic lead concentration limits and the minimum amount of biomass for the lead uptake experiment duration. The bioaccumulation experiment was performed using young and healthy floating aquatic plants of species S. auriculata. Approximately 30 grams of S. auriculata were put in growing at several 8-L recipients containing 5 L hydroponics solution and a non-toxic lead concentration of 2 mg L-1, during 29 days in a greenhouse. For the lead uptake experiment, seven collection times were set up at intervals of 1, 2, 5, 8, 22 and 29 days, including the zero time and was measured the growing solution temperature and pH, and the solution volume was monitored and deionized water was added to compensate the losses by evaporation. In order to measure the total lead concentration accumulated in aqueous solution obtaining from roots and leaves and growing solution, a Synchrotron Radiation Total Reflection X-Ray Fluorescence technique was used. The lead removal factor by S. auriculata after 29 days, in experimental conditions, was around 87 %. Moreover, it was observed a strong reduction of 50 % of lead concentration in liquid phase and lead accumulation in roots after the first 24 hours of experiment, while there a constant lead concentration in roots after the second day, indicating the transport and accumulation of lead into the leaves. The lead adsorption experimental data by S. auriculata were modeling by the irreversible adsorption kinetic of Langmuir. In the model, the equation system was resolved by DASSL algorithm and the kinetic parameters were obtained and optimized by an objective function using a SIMPLEX algorithm. The adsorption rate constant (k) value was 0.12 L d mg-1 Pb+2 while the maximum lead contents (qmax) value in the biomass was 0.15 mg Pb+2 g-1. The aquatic plant S. auriculata can be a good alternative for effluent treatment through both bioadsorption and bioaccumulation mechanism. The process based on the Phytoremediation technique using aquatic plants have become a attractive economical process due to its easy applicability , low operational costs and high efficiency. / Neste trabalho foi realizado um estudo do processo de bioacumulação de Pb+2 pela macrófita aquática Salvinia auriculata. Realizaram-se inicialmente testes toxicológicos e de crescimento para determinar os níveis tóxicos de Íons de Pb+2, estipular a massa mínima adequada, duração da experiência e os intervalos de coleta para o experimento da bioacumulação. O experimento da bioacumulação foi conduzido utilizando plantas jovens e sadias da espécie aquática e flutuante S. auriculata. Foram cultivadas, durante 29 dias em estufa, aproximadamente 30 gramas em recipiente de 8 L, em várias réplicas, contendo 5 litros de uma solução hidropônica (de Clark) e uma concentração não tóxica de 2 mg Pb+2 L-1. Foram realizadas 7 coletas, incluindo a coleta 0, a intervalos de 1, 2, 5, 8, 22 e 29 dias, monitorando pH e temperatura e fazendo a reposição de água devido a perdas por evaporação. As concentrações totais de chumbo, tanto na fase fluida como na raiz e na folha, foram determinadas pela técnica SR-TXRF. O fator de remoção de chumbo pela salvinia após 29 dias de cultivo, nas condições estudadas, foi de 87 %. Além disso, foi observado que a adsorção de chumbo foi rápida nas primeiras 24 horas, reduzindo em aproximadamente 50 %. A partir do segundo dia, a concentração de chumbo é quase constante, indicando a ocorrência de transporte e acumulação de chumbo na folha. Os dados experimentais de adsorção de Íons de Pb+2 pela S. auriculata foram representados pelo modelo cinético irreversível de Langmuir. No ajuste dos dados experimentais pelo modelo proposto, utilizou-se de uma função objetivo para otimizar os parâmetros de adsorção: a constante da taxa de adsorção e a quantidade máxima de sítios disponíveis na biomassa, cujos valores obtidos foram k = 0,12 L d mg-1 Pb+2 e qmax = 0,15 mg Pb+2 g-1. A planta S. auriculata mostrou-se uma boa opção para tratamento de efluentes através dos mecanismos de adsorção e bioacumulação. O processo de remoção de metal por planta aquática comprovou ser economicamente atrativo, de fácil disponibilidade, baixos custos operacionais e alta eficiência.
13

The impact and control of waterweeds in the Southern Mozambique Basin rivers

Langa, Sílvia da Fátima January 2013 (has links)
In Mozambique, establishment of aquatic weeds has been enhanced through the increased enrichment of water bodies by nutrient runoffs from human and agricultural wastes that lead to an increase in nitrate and phosphate in the water. The aquatic weeds, water hyacinth (Eichhornia crassipes), red water fern ( Azolla microphylla), water lettuce (Pistia stratiotes) and salvinia (Salvinia molesta) were found in most watercourses in Mozambique and are becoming aggressive in some watercourses, especially in the Umbeluzi and Incomati rivers. Farmers and people living along the rivers are aware of the negative impact of the water weeds because the large mats of weeds cause loss of shoreline and navigability along the rivers. Other commonly perceived effects of aquatic invasive plants in Mozambique rivers include: reduced navigable surface area; difficulties for fishermen, which reduces income; increased prevalence of insects and insect-borne disease, and decreased aesthetic value. The methods currently used for the control and management of the aquatic weeds are mechanical and manual control. Both methods are costly, time consuming, and only provide a short-term solution to the problem. The study found that the weevils Neochetina eichhorniae and N. bruchi were effective biological control agents in the study area but their impact is too gradual compared to the aggressive proliferation of water hyacinth. The one year lab-experiment clearly demonstrated that the water lettuce weed had a significant impact on the recruitment of macro-invertebrates to the artificial substrates, and water lettuce contributed to the reduction of oxygen in the water and consequent reduction of macro-invertebrate abundance and diversity. The biodiversity recovered at the same time in the pools containing water lettuce controlled by N. affinis and water lettuce controlled by herbicide, but richness and diversity of macro-invertebrates was higher in the water lettuce controlled by N affinis during the first sampling occasion compared to the water lettuce in pools controlled by herbicide, where macro-invertebrates increased only when DO levels recovered after water lettuce mat decay. The number of taxa recorded in this study is an indication of the significance of macro-invertebrates in an aquatic environment. This therefore emphasizes the need for more research efforts into macrophyte and macro-invertebrate associations in the aquatic system to better understand the implications of habitat modification arising from human activities. It will also enable us to be better equipped with a more appropriate ecological understanding for aquatic resources management.
14

Avaliação do potencial de utilização da macrófita aquática seca Salvinia sp. no tratamento de efluentes de fecularia / Evaluation of the potential use of dry aquatic macrophyte Salvinia sp. in an industrial cassava wastewater treatment

Limons, Rafaela da Silva 11 February 2008 (has links)
Made available in DSpace on 2017-07-10T18:08:09Z (GMT). No. of bitstreams: 1 Rafaela da Silva Limons.pdf: 1188810 bytes, checksum: 3222e9bb51995ce2bffdbb6505a56d20 (MD5) Previous issue date: 2008-02-11 / The industries of cassava processing are considered great polluting, therefore they generate highly pollutant a wastewater, the manipueira, with high concentration of organic substance. The method of treatment used in these industries is basically the system of stabilization. However, in function of the raised organic load, normally the effluent end if does not present in adequately favorable conditions for the ousting in hydrias resources, being essential a complementary treatment, so that the wastewater is adjusted to the current law. Thus, this work had for objective to study the removal of organic substance, nutrients and metals weighed, by means of a batelada system, for the dry biomass of the macrófita Salvinia sp. In this direction, with intention to investigate the factors that influence the capacity of removal of these contaminantes and to understand the mechanisms of this process, it was used as technique of factorial planning rotational central delineation composed - DCCR, verifying the influence of three independent 0 variable: pH initial, initial concentration of biomass - C and agitation -. The gotten results had shown that the best operational conditions had in accordance with varied the studied pollutant, thus best pH were: 5,8 for the match - P and zinc - Zn and 8,2 for the chemical demand of oxygen - DQO, nitrogen - N and have covered - Cu; the best concentration of biomass of 0,0013 g/mL for the DQO, the N, P and Zn and 0,0053 g/mL for the Cu and the 30 agitation of rpm for DQO and N and 120 rpm for the P, Zn and Cu. For the Compact disc removal of 100% in practically all was gotten the assays, in virtue of low the initial concentration of this metal. The gotten results had allowed to conclude respectively that in the best operational conditions the dry biomass of the Salvinia sp. influenced positively in process, reaching 97.91% of removal of DQO, 99.96% of P and 99.67% of N, with initial concentration of 20.480, 121,6 and 350 mg/L. Moreover, the results had shown to the promising character of the Salvinia sp. as biossorvente, being capable to adsorver up to 76,70% of íons of Zn, 99.79% of Cu and 100% of íons Compact disc, in industrias liquid residues contend small metal concentration heavy. The assays with the isotherms of adsorção of Zn and Cu had indicated that the capacity of biossorção of copper and 0,50 zinc had been approximately of 0,70 and meq/g in pH 5,0, being that the best adjustment occurred with the Isotherm of Sips. / As indústrias de processamento de mandioca são consideradas grandes poluidoras, pois geram um resíduo líquido altamente poluente, a manipueira, com alta concentração de matéria orgânica. O método de tratamento empregado nestas indústrias é basicamente o sistema de lagoas. Entretanto, em função da elevada carga orgânica, normalmente o efluente final não se apresenta em condições adequadamente favoráveis para o despejo em recursos hídricos, sendo essencial um tratamento complementar, para que o resíduo líquido esteja adequado à legislação vigente. Assim, este trabalho teve por objetivo estudar a remoção de matéria orgânica, nutrientes e metais pesados, por meio de um sistema batelada, pela biomassa seca da macrófita Salvinia sp. Neste sentido, com o intuito de investigar os fatores que influenciam a capacidade de remoção destes contaminantes e para se compreender os mecanismos deste processo, utilizou-se como técnica de planejamento fatorial o delineamento composto central rotacional - DCCR, verificando a influência de três variáveis independentes: pH inicial, concentração inicial de biomassa - C e agitação - A. Os resultados obtidos mostraram que as melhores condições operacionais variaram de acordo com o poluente estudado, assim o melhor pH foi: 5,8 para o fósforo - P e zinco - Zn e 8,2 para a demanda química de oxigênio - DQO, nitrogênio - N e cobre -Cu; a melhor concentração de biomassa de 0,0013 g/mL para a DQO, o N, P e Zn e 0,0053 g/mL para o Cu e a agitação de 30 rpm para a DQO e N e 120 rpm para o P, Zn e Cu. Para o Cd obteve-se remoção de 100% em praticamente todos os ensaios, em virtude da baixa concentração inicial deste metal. Os resultados obtidos permitiram concluir que nas melhores condições operacionais a biomassa seca da Salvinia sp. influenciou positivamente no processo, alcançando 97,91% de remoção de DQO, 99,96% de P e 99,67% de N, com concentração inicial de 20.480, 121,6 e 350 mg/L, respectivamente. Além disso, os resultados mostraram o caráter promissor da Salvinia sp. como biossorvente, sendo capaz de adsorver até 76,70% de íons de Zn, 99,79% de Cu e 100% de íons Cd, em resíduos líquidos industrias contendo pequena concentração de metais pesados. Os ensaios com as isotermas de adsorção de Zn e Cu indicaram que a capacidade de biossorção do cobre e zinco foram aproximadamente de 0,70 e 0,50 meq/g em pH 5,0, sendo que o melhor ajuste ocorreu com a Isoterma de Sips.
15

Estudio de un biosistema integrado para el postratamiento de las aguas residuales del café utilizando macrófitas acuáticas

RODRÍGUEZ VALENCIA, NELSON 02 April 2009 (has links)
El objetivo principal de la presente investigación es la generación de la información necesaria para el diseño de un biosistema integrado que utilice macrófitas para el postratamiento de las aguas mieles del café, buscando que sus efluentes generen el menor impacto negativo posible sobre el ecosistema acuático cafetero, presentando alternativas viables, desde el punto de vista técnico, económico, ambiental y social, para la adecuada disposición de la biomasa generada durante el proceso de depuración. En un primer ensayo, que constó de 18 tratamientos, se determinó el efecto de la concentración, en términos de DQO, de las aguas mieles del café tratadas mediante digestión anaerobia sobre el desempeño de sistemas acuáticos de tratamiento, a escala de mesocosmos, sembrados con las especies flotantes Eichhornia crassipes, Pistia stratiotes, Salvinia auriculata y la especie emergente Typha angustifolia, evaluando la remoción de los parámetros físico-químicos DQO, DBO5, ST, SST, NT, PT, K, S y del grupo de bacterias Coliformes. En un segundo ensayo, que constó de 24 tratamientos, se determinó el efecto de la carga orgánica de los efluentes de los sistemas anaerobios de tratamiento de las aguas mieles del café sobre el desempeño de sistemas acuáticos de tratamiento, sembrados con las mismas especies de plantas y determinando los mismos parámetros de remoción evaluados en el ensayo 1. Considerando el desempeño de las 4 especies acuáticas en la remoción de los parámetros DBO5, SST, NT, PT y K (medida como mg/m2-d) en los 2 ensayos evaluados, se determinó que la mejor especie para el postratamiento de las aguas mieles del café fue E. crassipes, seguida de P. stratiotes, T. angustifolia y S. auriculata. En un tercer ensayo, se evaluó el efecto del monocultivo vs la combinación de especies, en sistemas acuáticos para el postratamiento de las aguas mieles del café. / Rodríguez Valencia, N. (2009). Estudio de un biosistema integrado para el postratamiento de las aguas residuales del café utilizando macrófitas acuáticas [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/4342 / Palancia

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