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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.
61

Tratamento de efluentes de piscicultura utilizando sistema tipo wetland povoado com espécies de macrófitas aquáticas de três tipos ecológicos diferentes

Assunção, Argos Willian de Almeida [UNESP] 10 February 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-10Bitstream added on 2014-06-13T19:48:42Z : No. of bitstreams: 1 assuncao_awa_me_jabo.pdf: 2995291 bytes, checksum: 74067a6b3a92853f7bca5284c13487ca (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A aquicultura é uma atividade impactante para o meio ambiente, podendo causar eutrofização de corpos hídricos, introdução de espécies exóticas, transmissão de doenças e competição pelo uso da água. Os efluentes de criações de organismos aquáticos são ricos em matéria orgânica e nutrientes, nitrogênio e fósforo, decorrente de adubação, restos de ração e excreção. A partir de um viveiro de criação de pacu “Piaractus mesopotamicus” foi avaliado o impacto ambiental causado pela criação, a presença de organismos indicadores de contaminação fecal (Escherichia coli), e avaliada a eficiência de um sistema de tratamento tipo wetland construída utilizando três espécies de macrófitas aquáticas de tipos ecológicos diferentes: Eichhornia crassipes (flutuante), Ceratophyllum demersum(submersa) e Typha dominigensis (emersa). As variáveis analisadas foram temperatura, oxigênio dissolvido, condutividade elétrica, alcalinidade, dureza total, demanda química e bioquímica de oxigênio (DQO e DBO), nitrogênio (total, amoniacal, nitrito e nitrato), fósforo (total e ortofosfato) e o NMP de Escherichia coli, como ferramenta de análise foi aplicada uma análise multivariada de fatores. Os resultados demonstraram que a criação de pacu apresentou impacto ambiental significativo na qualidade da água do efluente do viveiro, gerando elevação da concentração de fósforo total, nitrogênio total e material particulado suspenso, aumento nos níveis de turbidez e demanda bioquímica e química de oxigênio. O sistema de tratamento foi eficiente no tratamento do efluente e todas as etapas do tratamento foram significativas para a remoção das variáveis relacionadas com o impacto ambiental. Todas as amostras apresentaram número mais provável de Escherichia coli dentro dos limites estabelecidos pela legislação brasileira / Aquaculture is responsible for various types of environmental impacts, causing eutrophication of water bodies, introduction of exotic species, disease transmission and competition for water use. The effluents from aquatic organisms breeding are rich in organic matter and nutrients, nitrogen and phosphorus, due to fertilization, food leftovers and excretion. From a pacu Piaractus mesopotamicus breeding pond was evaluated the environmental impact in the water, the presence of fecal indicator organisms (Escherichia coli) and evaluated the effluent treatment by a constructed wetland using three species aquatic macrophytes of different ecological types: Eichhornia crassipes (floating), Ceratophyllum demersum (submerged) and Typha dominigensis (onshore). The analyzed variables were temperature, dissolved oxygen, conductivity, alkalinity, total hardness, chemical demand and biochemical oxygen demand (COD and BOD), nitrogen (total, ammonia, nitrite and nitrate) and phosphorus (total and orthophosphate), for data analysis was applied a multivariate factor analysis. The results demonstrated that the pacu breeding showed significant environmental impact on water quality of the effluent, causing elevation of total phosphorus, total nitrogen and suspended particulate material, an increase in turbidity and chemical and biochemical oxygen demand. The treatment system was effective in the treatment of effluent and all stages of treatment were significant for the removal of variables related to environmental impact. The most probable number of E. coli was in accordance with Brazilian law in all samples
62

Variabilidade da condutividade hidráulica e de formas do nitrogênio em sistemas alagados construídos de escoamento horizontal subsuperficial / Variability of hydraulic conductivity and forms of nitrogen in constructed wetland systems of horizontal subsurface flow

Ferres, Gheila Corrêa 16 February 2012 (has links)
Made available in DSpace on 2015-03-26T13:23:42Z (GMT). No. of bitstreams: 1 texto completo.pdf: 2319739 bytes, checksum: 8d787f013c376eae45142c8b694720cf (MD5) Previous issue date: 2012-02-16 / Fundação de Amparo a Pesquisa do Estado de Minas Gerais / Constructed wetland systems of horizontal subsurface flow (CW-SSHF) are systems used in wastewater treatment. The objective of the present study was to assess possible changes in hydrodynamic conditions, through analysis of hydraulic conductivity and forms of nitrogen in CW-SSHF. In this study, six CW-SSHF were installed with dimensions of 0.6 m x 0.5 m x 2.0 m in height, width and length, respectively, with no bottom slope, filled with pea gravel and maintained in a greenhouse for the treatment of swine wastewater (ARS). CW-SSHF1 and CW-SSHF4 were not cultivated with any plant species (control), while CW-SSHF2 and CW-SSHF5 were planted with Tifton 85 (Cynodon spp.), and CW-SSHF3 and CW-SSHF6 were planted with Alligator weed (Alternanthera philoxeroides). During the experimental period six samples were collected of the influent (ARSA) and effluent (ARSE) of each CW-SSHF. Five hydraulic conductivity tests were also conducted along the length of the systems as a function of time, in order to evaluate the effects of vegetation, position and time on this variable. For comparison, hydraulic conductivity was determined in one CW-SSHF filled with pea gravel and submitted to flow of clean water. In all CW-SSHF an average organic loading rate of 411 kg ha-1 d-1 was applied with average flow of 0.069 m3 d-1, where the hydraulic retention time was equal to 3.6 d. The monitoring period was 63 days. At the end of the experiment, the plants were cut and the dry material yield was determined. The analysis of variance of hydraulic conductivity showed that only the interaction of position and vegetation effects was significant at the level of 10% probability. Hydraulic conductivity values in the thirds ranged from 1,392 m d-1 to 2,834 m d-1, where the differences between thirds of the CW-SSHF primarily occurred between the planted and non-planted systems by the Tukey test level 10% probability. All CW-SSHF presented average hydraulic conductivity values less than those obtained the system with clean water, which was 2680 m d-1. Dry matter yields in the different thirds of the bed ranged from 6.0 to 9.8 t ha-1 in the CW-SSHF planted with Tifton 85 and Alligator weed during the growth period of 60 days. The removal efficiency of total nitrogen (NT) and ammonium (N-NH4+) was considered low, ranging from 8 to 15% and 3 to 13%, respectively. Nitrate (N-NO3-) removal efficiency ranged from 45 to 53%. In all cases, the cultivated CW-SSHF showed higher efficiency for nitrogen removal. The CW-SSHF did not provide conditions which favored the occurrence of nitrification/denitrification. / Os sistemas alagados construídos de escoamento horizontal subsuperficial (SACs-EHSS) são sistemas utilizados no tratamento de águas residuárias. Com a realização deste estudo, objetivou-se avaliar possíveis alterações nas condições hidrodinâmicas, via análise da condutividade hidráulica, e nas formas do nitrogênio em SACs-EHSS. Para possibilitar este estudo, foram instalados seis SACs-EHSS, nas dimensões de 0,6 m x 0,5 m x 2,0 m de altura, largura e comprimento, respectivamente, sem declividade de fundo, preenchidos com brita zero e mantidos em casa de vegetação, para se efetuar o tratamento de água residuária de suinocultura (ARS). Os SAC-EHSS1 e SAC-EHSS4 não foram cultivados com qualquer espécie vegetal (controle), os SAC-EHSS2 e SAC-EHSS5 foram cultivados com capim tifton 85 (Cynodon spp.) e os SAC-EHSS-EHSS3 e SAC-EHSS6 cultivados com alternanthera (Alternanthera philoxeroides). Durante o período experimental foram coletadas seis amostras do afluente (ARSA) e do efluente (ARSE) de cada SAC-EHSS. Realizaram-se, também, cinco testes de condutividade hidráulica, ao longo do sistema e ao longo do tempo, a fim de se avaliar os efeitos da vegetação, posição e tempo sobre esta variável. A título de comparação, determinou-se a condutividade hidráulica em um SACs-EHSS preenchido com brita e submetido a escoamento de água limpa. Em todos os SACs-EHSS foi aplicada, em média, uma taxa de carregamento orgânico de 411 kg ha-1 d-1 e vazão média de 0,069 m3 d-1, sendo o tempo de detenção hidráulica igual a 3,6 d. O período de monitoramento foi de 63 dias. Ao final do experimento, foi feito um corte das plantas e determinada a produtividade de matéria seca. A análise de variância dos dados de condutividade hidráulica demonstrou que apenas a interação dos efeitos posição e vegetação foi significativa, em nível de 10 % de probabilidade. Os valores de condutividade hidráulica para os terços variaram de 1.392 m d-1 a 2.834 m d-1, sendo que as diferenças entre os terços dos SACs-EHSS ocorreram, basicamente, entre os vegetados e não vegetados, pelo teste Tukey, em nível de 10% de probabilidade. Todos os SACs-EHSS apresentaram condutividade hidráulica média inferior à obtida na brita limpa, que foi de 2.680 m d-1. A produtividade de matéria seca nos terços do leito variou de 6,0 a 9,8 t ha-1, nos SACs-EHSS cultivados com tifton 85 e alternanthera, em um período de 60 dias de cultivo. A eficiência na remoção de nitrogênio total (NT) e amônio (N-NH4+) foram consideradas baixas, variando de 8 a 15% e 3 a 13%, respectivamente. A eficiência de remoção de nitrato (N-NO3-) variou de 45 a 53%. Em todos os casos, os SACs-EHSS cultivados apresentaram maior eficiência na remoção de nitrogênio. Os SACs-EHSS não proporcionaram condições que favorecessem a ocorrência de nitrificação/desnitrificação.
63

Avaliação de um sistema piloto para tratamento de efluentes de sala de ordenha de bovinocultura / Evaluation of a pilot system treating milking parlor effluent

Silva, Edu Max da, 1954- 30 July 2007 (has links)
Orientador: Denis Miguel Roston / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-09T13:06:32Z (GMT). No. of bitstreams: 1 Silva_EduMaxda_M.pdf: 12592705 bytes, checksum: fa560f6bfbe78ace9e89fc4061f0170c (MD5) Previous issue date: 2007 / Resumo: Uma das maiores dificuldades no gerenciamento do confinamento de gado leiteiro é a grande quantidade de dejetos produzidos diariamente numa área reduzida, que pode ser uma ótima opção de fertilizantes ou um enorme potencial poluente, dependendo de como é feita a disposição destes dejetos, um dos principais desafios para criadores e especialistas. No Brasil, o destino dos efluentes brutos dos confinamentos de vacas leiteiras, foi e continua sendo os cursos d¿água usando o ultrapassado método da diluição, como única forma para eliminar os resíduos das instalações e com isso podendo provocar a eutrofização de rios, riachos, lagos e lagoas. Foi implantado um projeto piloto, no Sítio Nossa Senhora da Conceição, com as condições tanto opográficas como climáticas idênticas, para tratar 10% de um efluente similar ao produzido na UEP de bovinocultura leite da EAFI/MG. A ETE piloto era composta por três unidades, sendo uma lagoa anaeróbia, uma lagoa facultativa e um pós-tratamento utilizando um leito cultivado (¿constructed wetland¿). A lagoa anaeróbia não suportou o lançamento do efluente bruto lançado na ETE piloto para tratamento de águas residuárias oriundas da sala de ordenha da bovinocultura leite. Para reduzir a quantidade de sólidos flutuantes na lagoa anaeróbia, a recomendação apresentada foi a construção de um tanque tipo séptico capaz de reter os sólidos flotantes. O leito cultivado foi a unidade da ETE piloto que não aparentou mudanças externas. A ETE piloto registrou uma remoção média dos parâmetros analisados em torno de: fósforo na forma de (P) e (PO4) 80%; amônia (NH3-N) e nitrato (NO3) 88%; DQO 89%, pH médio das amostras analisadas em 6,23; sólidos (ST) e (STV) 67%; turbidez 60%. Em se tratando de resíduos líquidos da produção animal, pode-se afirmar que o resultado é positivo, demonstrando que está opção de sistema de tratamento tem grande potencial de aplicação / Abstract: One of the major concerns in dairy cattle lodging management is the great amount of manureproduced daily in a reduced area, that can be an excellent fertilizer option or an enormous pollutant potential, depending on the disposal procedures. In Brazil, the destination of raw effluent of lodged dairy cattle was in the past and continues nowadays being the water courses using the conventional and condemned method of the dilution, as only form to eliminate the residues of the installations which is one of the reasons for eutrophication of rivers, streams, lakes and ponds. A pilot plant was installed to treat 10% of the effluent produced in the dairy parlor installations of the EAFI/MG. The pilot plant was designed with three units: an anaerobic lagoon followed by a facultative pond and a subsurface constructed wetland. The pilot plant presented the following average removal: phosphorus, 80%; nitrate, 88%; COD, 89%; total solids, 67%; and turbidity, 60%. The pH during the whole operation maintained around the value of 6,2. The study conclued that the system presented a great potential for treatment of dairy parlor effluent / Mestrado / Agua e Solo / Mestre em Engenharia Agrícola
64

Avaliação da eficiência de sistemas alagados construídos em operação por bateladas no tratamento de efluentes da indústria de laticínios / Evaluating the effectiveness of wetland systems built in operation for batch in the treatment of the wastewater in the dairy industry

Mendonça, Henrique Vieira de 25 February 2011 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-07-19T13:23:26Z No. of bitstreams: 1 henriquevieirademendonca.pdf: 11929351 bytes, checksum: 9efab95f034b43d60bf37ea6393484be (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-22T15:14:40Z (GMT) No. of bitstreams: 1 henriquevieirademendonca.pdf: 11929351 bytes, checksum: 9efab95f034b43d60bf37ea6393484be (MD5) / Made available in DSpace on 2016-07-22T15:14:40Z (GMT). No. of bitstreams: 1 henriquevieirademendonca.pdf: 11929351 bytes, checksum: 9efab95f034b43d60bf37ea6393484be (MD5) Previous issue date: 2011-02-25 / Os sistemas alagados construídos (SACs) aplicados na depuração de águas residuárias de laticínios são muito pouco estudados no que diz respeito ao dimensionamento, métodos operacionais e eficiência destes sistemas. Sendo assim, neste trabalho procurou-se estudar a influência de substratos e espécies vegetais cultivadas, sobre a eficiência na remoção de DBO e nutrientes de seis unidades experimentais operando em bateladas em escala piloto. Os seis SACs foram construídos em tanques de PEAD com volume de 115 litros, com relação comprimento/largura na proporção de 2:1, obedecendo a dinâmica de escoamento em pistão. Os substratos utilizados foram a brita 0 em três dos SACs e brita 0 e areia em outros três, na proporção de 80% brita e 20% areia. Quatro das unidades experimentais foram cultivadas e duas mantidas como testemunhas. As espécies selecionadas foram as macrófitas Typha dominguensis (taboa) e o Hedychium coronarium (lírio-do-brejo). O sistema apresenta a vantagem de utilizar o sistema solo-planta-microrganismos e a radiação solar como reatores para depuração dos resíduos a um baixo custo. Trata-se de um sistema de fácil instalação, operação e manutenção e que, além de apresentar desempenho favorável nas condições climáticas do Brasil, ainda é esteticamente adequado ao ambiente. A eficiência média mínima encontrada no tratamento foi de 77,8 % e máxima de 95,2 % em termos de DBO5, 29,4 a 53,5% e 16,8 a 48.2% na remoção de Nitrogênio e Fósforo respectivamente. Os seis tratamentos apresentaram remoção de compostos carbonáceos biodegradáveis semelhantes. O mesmo não ocorreu com a eficiência de remoção de nutrientes, sendo que as unidades experimentais vegetadas superaram significativamente as não vegetadas. O tratamento mostrou-se eficiente, havendo a remoção prévia do alto índice de compostos orgânicos e redução considerável de nutrientes eutrofizantes, principalmente compostos nitrogenados. Embora preliminar, o estudo mostrou que os sistemas alagados construídos operando em bateladas podem ser utilizados no tratamento de águas brutas de laticínios. / The present study concerns the influence of substrates and cultivated plant species on the removal efficacy of BOD of six pilot-scale batch-working experimental units. The six SACs was mounted in 115 litters in volume HDPE tanks, in the length/width ratio of 2:1, in order to obey the dynamics of plug flow. In three of the SACs, gravel 0 was used as substrate, while gravel # 0 and sand was used in the others, in the percentage of 80% and 20%, respectively. Four of the experimental units were cultivated, and two sustained as witness. Selected species was the macrophytes, Typha domingensis (southern cattail) and Hedychium coronarium (ginger lily). The system offers the advantage of using the soil-plant-microorganisms and solar radiation as reactors for purification of waste at low cost. It is a system for easy installation, operation and maintenance, which, besides showing favorable performance in the climatic conditions of Brazil, yet is aesthetically suitable for the environment. According to the results, the maximum efficiency rate was 77.8% and the minimum efficiency rate was 95.2% in terms of DBO5. Besides a rate between 29.4 and 53.5% and a rate between 16.8 and 48.2% in removal of Nitrogen and Phosphorus respectively. The six treatments showed the removal of similar biodegradable carbonaceous compounds. Nevertheless, the same do not occurs with the removal efficacy of nutrients, since the vegetated experimental units considerably overcome the not-vegetated experimental units. The treatment has been shown efficient, having the earlier removal of the high index of organic compounds, and a considerable reduction of nutrients which are euthrophics, mainly the nitrogenated compounds. Although preliminary, this study showed that the batch-working constructed wetlands systems can be used in treatment of dairy crude water.
65

Removal efficiency of indicator organisms and tetM prevalence in enterococci in a constructed wetland for wastewater treatment

Olsson, Linnea January 2013 (has links)
Indicator organisms like coliforms, E. coli and enterococci are normally associated with the intestinal tract of warm-blooded animals, and can thus be used for indicating fecal contamination of water. This study investigated the removal efficiency of indicator organisms in a free water surface constructed wetland used for additional treatment of municipal wastewater. The species composition of enterococci and the prevalence of the tetracycline resistance gene tetM were also investigated. Samplings were done at five different sites: at the inlet, within and at the outlet of the wetland, as well as upstream and downstream of the wetland outlet into the adjoining river. A total of 86 enterococci isolates were characterized as E. faecalis, E. faecium or other Enterococcus spp., and the two former were also screened for the tetM gene. The investigated wetland showed a high removal rate of indicator organisms, with a removal of approximately 98%. E. faecium was identified as the predominant species in the wetland at a mean of 55.8%. In comparison, only 9.3% were E. faecalis, while other Enterococcus spp. were found to comprise 34.9%. Of the 56 isolates identified as E. feacalis or E. faecium 10.7% were positive for the tetM gene. The high removal of bacteria shown by this investigation provides further evidence of the benefits of constructed wetlands on wastewater treatment. It also offers a first indication of the Enterococcus spp. composition in Ekeby wetland, Eskilstuna, Sweden, and shows that the prevalence of the tetM gene is relatively low at this point in time.
66

Landscapes that facilitate learning : Outdoor spaces that improve learner performance in Atteridgeville schools

Janse van Rensburg, Jako Stegmann 09 December 2013 (has links)
Low learner performance is one of the greatest challenges that confront South Africans in this post-apartheid era. Despite valiant efforts on the government’s part to improve the education system every year, successful learners are not coming through the ranks in sufficient numbers. In the case of Atteridgeville, an old township near the Pretoria Central Business District, the phenomenon of low learner performance is reflected in the quality of schoolyards and the behavior of learners. Schoolyards are degraded, learners lack confidence, they are not enthusiastic about their schools, they do not interact with the communities around their schools, and they do not venture into the physical landscape outside their schools. The question arises whether the landscape outside the classroom is not, in fact, contributing to the problem. If this is so then a way must be found to manipulate the landscape so that obstacles to learner performance are removed and learning is facilitated. This thesis explores the notion that the outdoor landscape in Atteridgeville can play a role in helping learners reach their potential. Therefore Atteridgeville will be the departure point for the investigation. The investigation will result in a project location which will be further investigated to identify its inherent opportunities and constraints. The design response to these opportunities and constraints, coupled with both theoretical and conceptual backing, will inform the project at master plan and detail design level. Methods must be found to unlock the didactic and experiential potential of the schoolyard and surrounding landscape in a township where open green spaces are under threat and physical and social obstacles to learner performance exist. / Dissertation ML(Prof)--University of Pretoria, 2014 / Architecture / ML(Prof) / Unrestricted
67

Efficacité de zones tampons humides à réduire les teneurs en pesticides des eaux de drainage / Effectiveness of constructed wetlands to reduce the pesticide concentrations in drain water

Vallée, Romain 24 April 2015 (has links)
En Lorraine, le drainage fréquent des sols argileux favorise les transferts des intrants agricoles (pesticides et engrais) vers les eaux de surface. Dans ce cas, les bandes enherbées réglementaires (BCAE de la PAC) installées en bordure de cours d’eau sont court-circuitées et ne jouent plus leur rôle épurateur vis-à-vis des eaux de surface. Ainsi, des zones tampons humides artificielles (ZTHA) sont préconisées pour prendre le relais des bandes enherbées. Généralement, ces ZTHA sont installées à l’échelle du bassin versant ou du groupe de parcelles et sont donc de taille conséquente, les rendant concurrentielles de la surface agricole utile (SAU). L’objectif de ce projet de recherche est donc d’évaluer l’efficacité de deux ZTHA de taille réduite, installées dans la bande enherbée entre la parcelle drainée et le ruisseau. Pour cela, une approche multi-échelles intégrant des expériences de laboratoire en batch, des suivis dynamiques en bacs pilotes et un monitoring à la parcelle a été mise en place. Afin d’évaluer l’efficacité des ZTHA au cours des saisons de drainage 2012/13 et 2013/14, le suivi des teneurs en nitrate et de 79 pesticides a été réalisé dans les eaux en entrée et en sortie des ZTHA, ainsi que dans diverses matrices environnementales (sols, sédiment, paille, végétaux). Pour les deux dispositifs, la réduction du flux de nitrate s’est montrée stable, comprise entre 5,4 et 10,9 %, alors que la réduction du flux de pesticides s’est montrée très variable, comprise entre -618,5 et 100 %. Cette variabilité a été expliquée par quatre comportements distincts des molécules. Les fortes valeurs négatives d’efficacité ont été expliquées par une contamination des dispositifs à la suite d’épisodes de ruissellement connexes pour des molécules solubles telles que le 2,4-MCPA ou l’isoproturon. Pour ces deux molécules, l’étude de sorption a montré leur faible affinité avec les matrices environnementales, facilitant leur transport par les eaux de ruissellement et de drainage. D’autres molécules, telles que le boscalide ou l’OH-atrazine, ont présenté des abattements proches de 0. Pour le boscalide, ce comportement a été montré au laboratoire, en accord avec ses fortes capacités d’adsorption et de désorption observées lors des études de sorption et en bacs pilotes. Enfin, certaines molécules ont montré des abattements, allant de 9,9 à 100 %, en lien avec leur faible persistance (2,4-MCPA, clopyralid, mésosulfuron-méthyl,…) ou leur forte affinité pour les matrices environnementales (diflufenicanil, propiconazole, propyzamide,…). Ces ZTHA de taille réduite, installées dans les bandes enherbées, sont donc efficaces pour limiter la contamination des eaux de surface par les eaux de drainage agricole. Ainsi, la multiplication de ces dispositifs à l’échelle de la parcelle dans le paysage agricole permettrait de réduire la contamination des eaux de surface par les pesticides et les nitrates tout en préservant la SAU. Toutefois, l’efficacité de ces ZTHA restant limitée vis-à-vis de certains pesticides présentant un Koc faible et une DT50 élevée, leur installation ne doit pas remettre en cause la réduction en amont des apports phytosanitaires sur les parcelles / In Lorraine, the drainage of clay soils contributes to transfer of agricultural inputs (pesticides and fertilizers) towards surface waters. In this case, the regulatory grass strips (CAP regulation) installed along rivers are bypassed and no longer effective in purifying surface water. Thus, constructed wetlands (CWs) are recommended to take over grass cover bands. Generally, these CWs are installed at watershed scale or at that of several plots and they are therefore quite huge, making them competitive in the cultivated land. The objective of this project is to assess the effectiveness of two small CW, installed in the grass cover band between the drained plot and the river. For this, a multi-scale approach was set up integrating laboratory experiments in batch, pilot study taking into account the water dynamics and monitoring at field scale. The effectiveness of CW was assessed during the 2012/13 and 2013/14 drainage seasons. The nitrate and 79 pesticides concentrations were monitored at inlet and outlet of CWs and in various substrates (soils, sediment, straw and plants). For both devices, the removal efficiencies measured for nitrate were stable and ranged from 5.4 to 10.9 % of inlet amounts while the reduction of pesticide flows was very variable, ranging from -618.5 to 100 %. This variability was explained by four distinct behaviors. The high negative efficiency values were attributed to neighboured runoff events after heavy rains, for soluble molecules such as 2,4-MCPA or isoproturon. For both molecules, the sorption study showed low affinity for environmental substrates, facilitating their transport by runoff and drainage water. Other molecules such as boscalid or OH-atrazine showed effectiveness close to 0 %. For boscalid, this behavior has been observed in laboratory sorption and pilots studies, in agreement with its strong adsorption and desorption capacities. Finally, some molecules have shown reductions ranging from 9.9 to 100 %, in agreement with their low persistence (2,4-MCPA, clopyralid, mesosulfuron-methyl, ...) or their high affinity for environmental substrates (diflufenican, propiconazole or propyzamide). These small CWs, located in the grass cover bands, are effective in minimizing the contamination of surface waters by agricultural drainage water. Thus, multiplying the number of these devices at the plot scale in the agricultural landscape would reduce the contamination of surface waters by pesticides and nitrates while preserving the cultivated land. However, the effectiveness of these CWs are limited for pesticides with a low Koc and a long DT50; thus their installation in plot must not call into question the reduction in the use of pesticides
68

Srovnání účinnosti malých balených ČOV a kořenových ČOV / The comparison of two waste water treatment systems - constructed wetlands and mechanical.

Dudíková, Kristýna January 2010 (has links)
This thesis is focused to the comparison of two wastewater treatment systems - constructed wetlands and mechanical-biological wastewater treatment plant. The main goal of the theses is to compare two types of wastewater treatment systems and to evaluate hypothesis that constructed wetlands are cheaper and more efficient than mechanical-biological wastewater treatment plant. To be able to compare two various wastewater treatment systems 18 (9 constructed wetlands and 9 mechanical-biological plants, three size groups of both types of plants) wastewater treatment plant were chosen and compared. The treatment effectiveness, investment and operating costs, advantages and disadvantages of both the systems were compared. The information about all individual systems was obtained from the local municipalities, operators and partially from the Ministry of Environment of CR. Obtained data involved treatment technology, amount of annual treated water, building data and capital and operating costs. In some waste water treatment plant (WWTP) the water samples were taken and the analyses of chosen parameters (not measured in WWTP) were done. Once in 2010 year the samples of water, sediments and sludges were taken and the analyses of heavy metals was done. For assessment of operational problems in constructed...
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Modelling phosphorus dynamics in constructed wetlands upgraded with reactive filter media

Hamisi, Rajabu January 2017 (has links)
Developing low-cost and effective technologies to upgrade phosphorus (P) removal from the catchment runoffs and rural wastewater treatment facilities is one of the main research agendas to save the Baltic Sea from eutrophication. In Sweden, the construction of the constructed wetlands has been one of the environmental objectives for wastewater quality improvement in the small communities. However, the insufficiently understanding of the mechanisms underlying the process of phosphorus mobility and sorption in the constructed wetlands has limited design of the effective constructed wetlands. To provide the better understanding of sorption process in the catchment and constructed wetland system, this thesis used the GIS-based Soil and Water Assessment Tool (SWAT) to predict phosphorus mobility and identify the critical diffusing sources of phosphorus loss in the Oxunda catchment (Paper I). Then, the study developed the three-dimensional numerical Reactive TRAnsPort Model (RETRAP - 3D) in the COMSOL Multiphysics® for evaluating the long - term sorption processes and removal efficiencies of the porous reactive media for upgrading the performance of constructed wetlands (Paper II and III). The latter model coupled many physics equations to solve process of water flow, reaction kinetics and solute transport in the porous reactive adsorbent media for application in the constructed wetlands. The data from the field measurements and column experiments have been used to demonstrate the model simulation accuracy to capture the process of phosphorus sorption in the real environment. Modeling results ranked the phosphorus removal efficiency of the adsorbent media as follows: Polonite® (88 %), Filtralite P® (85%), BFS (62%), Wollastonite (57 %). The satisfactory agreement which obtained between the simulated outputs and measured data confirmed that the SWAT and RETRAP-3D are useful tools for describing various processes in the complicated system. However, further study is required to generate and validate more experimental data to evaluate the sensitivity of local parameters. / <p>This reserch project was finacially supported by Lars Erik Lundberg scholarship foundation for projectnumber (2015/34 and 2016/12), ÅkeochGreta Lissheds Stiftelsen for project number (2015-00026), J.Gust. Richert Stiftelsen and Ecopool researchproject for smart and sustainable environment. QC 20170523</p>
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Long-Term Nutrient Removal and Nutrient Mass Balance of a Free Water Surface Constructed Wetland Polishing Municipal Lagoon Effluent

Patel, Meetkumar 11 January 2023 (has links)
A large pilot-scale free water surface (FWS) constructed wetland polishing effluent from an annual (spring) discharge municipal lagoon was operated for ten years followed by eleven years of dormancy and then restarted with an increase in operating depth. No significant effect of system aging was observed on Biological Oxygen Demand (BOD), total phosphorus (TP), and soluble reactive phosphorus (SRP) removal efficiencies, although internal TP water column concentrations in the first wetland and pond cells increased with time due to resuspension of accumulated sediments. Nitrate and ammonium removal efficiencies were higher during the start-up period due to plant establishment, while organic nitrogen and nitrate removal efficiencies increased during the restart period, likely due to a combination of the increased operating depth and accumulated sediments. No seasonal temperature effect was observed for nitrate or BOD removal efficiency, however, TP removal efficiencies increased with increasing influent concentrations due to seasonal algae growth. TSS removal efficiency increased significantly during the restart period, most likely due to an increase in the operating depth. Phosphorus was found to be mostly stored in the soil, followed by sediment and plants, while nitrogen was found to be stored more in plants, followed by soil and sediment. The wetland system was shown to be effective at the long-term removal of organic matter (BOD5 < 10 mg/L) and TP (87% average removal efficiency), while TSS removal efficiency increased to 97% with an increase in operating depth from 25 to 50 cm.

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