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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.
41

Conversão de compostos nitrogenados em reatores biológicos: operação, caracterização microbiológica e filogenética / Nitrogen compounds conversion in biological reactors: operation, microbiological and phylogenetic characterization

Tiago Henrique Martins 27 August 2010 (has links)
Esta pesquisa objetivou enriquecer biomassa capaz de realizar a oxidação anaeróbia do amônio (anammox) utilizando inóculo proveniente de reator nitrificante-desnitrificante, com a finalidade de estabelecer biofilme nitrificante-anammox em reator de leito fixo. O enriquecimento foi realizado em reator operado em bateladas sequenciais (RBS), com volume útil de 5 L e tempo de ciclo, inicialmente, de 56 h, e depois, sem tempo predeterminado (estratégias I e II). Após 89 dias de operação, 27,2 mg de \'N\'-\'N0 IND.2\'POT.-\'/L e 32,1 mg de \'N\'-\'NH IND.4\'POT.+\'/L foram consumidos concomitantemente. A estratégia III consistiu de batelada alimentada com ciclos de sete dias com afluente contendo 210 mg de cada composto nitrogenado. Na última estratégia (IV) a operação foi com ciclos de 24 h. Nessa etapa, a carga nitrogenada aplicada (CNA) foi aumentada de 155 g de \'N\' (\'N\'-\'N0 IND.2\'POT.-\' \'N\'-\'NH IND.4\'POT.+\')/\'M POT.3\' dia para 1.405,7 g de \'N\'/\'M POT.3\' dia com eficiências de conversão de nitrogênio de 91,7% e 98,0%, respectivamente. Essa biomassa foi inoculada em reator de leito fixo ascendente (RLF) visando estabelecimento da biomassa anammox em meio suporte (PEBD). Sob tais condições foi obtido eficiência de conversão de nitrogênio de 97,6% e carga nitrogenada removida média de 598,5 \'+ OU -\' 22,5 g \'N\'/\'M POT.3\' dia. Após estabelecimento de biomassa anammox, foi adicionado lodo ativado da indústria Volkswagen (São Carlos-SP) para formação de biofilme nitrificante-anammox. Nessa fase, a remoção de nitrogênio foi de 19,2% para CNA de 112,2 g \'N\'/\'M POT.3\' dia. A atividade anammox específica máxima foi 33,5 mg \'N\'-\'NH IND.4\'POT.+\'/g SSV h com a biomassa submetida à 50 rpm. Paralelamente ao processo de enriquecimento, foi verificada a influência de micronutrientes em condições nitrificantes em três quimiostatos, nas seguintes condições: Q1 alimentado com meio contendo solução de micronutrientes completa, Q2 alimentado sem solução de micronutrientes e Q3 alimentado com solução de micronutrientes sem o elemento Boro (quimiostato experimental). Nas três condições a estabilidade foi atingida com 11 dias de operação com conversão média de nitrogênio amoniacal de 99 \'+ OU -\' 1,5%, 94,6\'+ OU -\' 6,3% e 93,3\'+ OU -\' 7,3%, para Q1, Q2 e Q3, respectivamente, para 79 mg \'N\'-\'NH IND.4\'POT.+\'/L afluente. Após 450 dias de operação do RBS foi constatado semelhança do clones com Brocadia anammoxidans, Planctomycetes, Proteobacteria, Chlorobi, Nitrospira, filo Chloroflexi e ao filo candidato OP 11. A composição microbiana encontrada no RLF com 139 dias de operação (final da fase anammox) foi de 48% dos clones relacionados à B. anammoxidans, 4% relacionados à Planctomycetes não cultivados, 12% relacionados à Proteobacteria, 8% relacionados à Chlorobi, 24% relacionados à Nitrospira, 4% relacionados ao filo Chloroflexi. Pode-se concluir que a biomassa aderida em PEBD selecionou positivamente microrganismos anammox e Nitrospira e negativamente aos filamentos relacionados ao filo Chloroflexi. / This research aimed to enhance biomass capable of performing anaerobic ammonia oxidation (anammox) using inoculum from nitrifying-denitrifying reactor, with the goal of establishing nitrifying-anammox biofilm in fixed bed reactor. The enrichment was performed in sequencing batch reactor (SBR), with a volume of 5 L and cycle time, initially, 56 h, and then, without pre-set time (strategies I and II). After 89 operation days, 27.2 mg \'N\'-\'N0 IND.2\'POT.-\'/L and 32.1 mg \'N\'-\'NH IND.4\'POT.+\'/L were consumed concomitantly. The strategy consisted of fed batch III with seven days cycles with influent containing 210 mg of each nitrogen compound. The last strategy (IV) was with 24 h/cycle. At this strategy, the nitrogen applied load (NAL) was increased from 155 \'N\' (\'N\'-\'N0 IND.2\'POT.-\' + \'N\'-\'NH IND.4\'POT.+\')/\'M POT.3\' to 1405.7 g \'N\'/\'M POT.3\' day with conversion efficiencies of 91.7% nitrogen and 98.0%, respectively. This biomass was inoculated into fixed bed reactor up (FBR) in order to establish the anammox biomass in support medium (LDPE). Under such conditions was obtained nitrogen conversion efficiency of 97.6% and nitrogen load removed an average of 598.5 \'+ OU -\' 22.5 g \'N\'/\'M POT.3\' day. After establishment of anammox biomass it was added activated sludge - Volkswagen industry (São Carlos-SP) - for nitrifying-anammox biofilm. At that stage the removaI of nitrogen was 19.2% to 112.2 g CNA \'N\'/\'M POT.3\' day. Simultaneously to enrichment process, was verified the influence of micronutrients in nitrifying conditions in three chemostats, as follows: Q1 fed with medium containing micronutrients solution complete feeds without Q2 and Q3 micronutrients solution fed micronutrients solution without the element Boron (chemostat experiment). In the three conditions stability was achieved with 11 days of operation with average conversion of ammonia nitrogen of 99 \'+ OU -\' 1.5%, 94.6 \'+ OU -\' 6.3% and 93.3 \'+ OU -\' 7.3% for Q1, Q2 and Q3 respectively for 79 mg \'N\'-\'NH IND.4\'POT.+\'/L. After 450 days of operation of the RBS was found similarity of clones with Brocadia anammoxidans, Planctomycetes, Proteobacteria, Chlorobi, Nitrospira, Chloroflexi phyla and candidate phylum OP 11. The microbial composition found in the FBR with 139 days of operation (end of anammox phase) was 48% of clones related to B. anammoxidans, 4% related to uncultured Planctomycetes, Proteobacteria related to 12%, 8% related to Chlorobi, 24% related to Nitrospira, 4% related to the phylum Chloroflexi. It can be concluded that biomass adhered to LDPE selected anammox microorganisms and Nitrospira positively, and negatively to the filaments related to the Chloroflexi phylum.
42

Conception et évaluation de deux systèmes de retrait de la charge azotée provenant de l’effluent d’un système de digestion anaérobie

Lemonde, Maxime January 2015 (has links)
Les systèmes de digestion anaérobie (DA) sont des systèmes biomécaniques complexes qui demandent une conception et une fabrication particulières pour chaque cas. Ces systèmes, à la base, utilisés sur les fermes pour transformer le fumier en biogaz et en engrais, sont maintenant utilisés pour transformer tout type de matières organiques allant des déchets de table aux rejets industriels. Ce mémoire porte sur deux post-traitements possibles de l’effluent de tels systèmes dans le but d’améliorer le bilan environnemental, de réduire l’impact sur les stations de traitement des eaux usées (STEU) et de poser les bases pour de futures recherches sur le recyclage de la portion liquide de cet effluent vers les systèmes de digestion anaérobie. Le post-traitement permet d’améliorer le bilan environnemental en évitant de relâcher certains contaminants dans la nature ou vers les STEU, ce qui pourrait gravement affecter leur efficacité de traitement. Les traitements retenus sont un traitement biologique (figure 2) par nitrification et dénitrification de l’effluent ainsi qu’un traitement chimique par stripage à l’air. Le traitement biologique a permis de retirer 50% de la charge azotée pour des conditions d’opération données comparativement à plus de 90% pour le traitement chimique. Le système qui s’avère le plus efficace en terme de temps de traitement (moins de 12 heures versus 5 jours), de flexibilité par rapport aux charges (jusqu’à 6000 ppm d’azote ammoniacal versus moins de 2000 ppm) et d’efficacité du retrait en général est le traitement par stripage à l’air. Comparativement au traitement biologique, ce traitement ne demande pas de temps de démarrage, ce qui permet aux usines de biométhanisation d’être conformes à leurs objectifs de rejet dès le premier jour.
43

Hur ska Kiruna avloppsreningsverk minska sin påverkan på recipienten Luossajokki? : En utredning av möjliga åtgärder inför en framtida omprövning av tillståndet

Lindgren, Sandra January 2020 (has links)
En alltför stor tillförsel av näringsämnen till sjöar och vattendrag orsakar miljöeffekter i form av ökad tillväxt av planktoniska alger i vattenmassan (algblomning) och igenväxning av stränder, syrebrist i bottensedimenten och ändrad artsammansättning för djurplankton och fisk. Utsläpp av kväve i from av ammonium (NH4+) kan omvandlas till ammoniak (NH3) som är toxiskt för de flesta vattenlevande organismer redan vid mycket låga koncentrationer.  För många svenska avloppsreningsverk väntas en skärpning av befintliga reningskrav avseende kväve och fosfor i samband med nya tillståndsprövningar i enlighet med vattendirektivet. Samtidigt kan nya typer av krav komma att baseras på de prioriterade ämnen som identifierats utifrån ramdirektivet. Kiruna avloppsreningsverk väntas vid en framtida omprövning av tillståndet behöva investera i en kvävereningsanläggning för att minska utgående halt av ammonium i det renade avloppsvattnet och bidra till att recipientens status uppnår ”God status”. Genom att jämföra för- och nackdelar med olika reningstekniker med hänsyn till inkommande halter kväve, kvävets väg genom processen, anläggningens lokalisering och tillgängliga ytor, investeringskostnader samt det kalla klimatet har denna studie undersökt olika möjligheter för att reducera mängden ammoniumjoner genom oxidation vid Kiruna avloppsreningsverk. Studien visade att det vid en framtida investering finns ett flertal fördelar med att välja en reaktor med biofilmsbärare (MBBR) som kompletterande steg för kväverening. / An excess of nutrients in lakes and watercourses can cause environmental effects such as increased growth of planktonic algae (algal bloom) in the water and reed vegetation at the beaches, lack of oxygen in the bottom sediment and altered species composition. Emission of nitrogen in the form of ammonium (NH4+) can be converted to ammonia (NH3) which is toxic to most aquatic organisms already at very low concentrations. For many Swedish waste water treatment plants, stricter emission standards is expected for nitrogen and phosphorus in accordance with the EU Water Framework Directive (WFD). Simultaneously, new types of emission requirements may be based on the priority substances identified on the basis of the WDF. In the future, the Kiruna waste water treatment plant is expected to need to invest in a nitrogen treatment plant to reduce the emissions of ammonium in the purified wastewater, to help the recipient’s status achieve “Good status”. By comparing the advantages and disadvantages of various purification techniques with regard to incoming nitrogen levels, the levels of nitrogen through the process, the plant’s location and available areas, investment costs and the cold climate, this study has investigated various possibilities for reducing the amount of ammonium by oxidation at the Kiruna waste water treatment plant. The study showed that in a future investment, there are several benefits of choosing a moving bed biofilm reactor (MBBR) as a complementary step for nitrogen removal.
44

Nitrous oxide emissions from deammonification process under different operation conditions.

Mazurek, Agnieszka January 2015 (has links)
Wastewater treatment plays significant role in the environmental protection. The process has direct impact on quality of air and water. All treated sewage reaches fresh water reservoirs as well as gasses escaping from the process are emitted to the atmosphere. Main aim of the thesis is to determine N2O emissions from partial nitritation/Anammox (deammonification process) in one-stage system applied in MBBR technology. Whole project was operated successfully on two pilot-scale reactors parallel, fed by the same reject water. Both reactors were filled to capacity of 200 L each, where 40% of the working volume was fulfilled by Kaldnes carriers suspended in liquid by mechanical stirrer. First reactor (R1) presented strategy of intermittent aeration with ratio (R=1/3) and stable DO concentration at amount of 1.5 mg O2/L, whereas second one (R2) operated in constant aeration with variable values of dissolved oxygen which differ in range of 1.0-2.5 mg O2/L. Every week analyses of ammonium and nitrogen forms were carried out in influent and effluent by Hach-Lange cuvettes. Results of measurements showed high NH4+-N removal efficiency of approximately 95% for R1 reactor and 86% for R2. During the process, the continuous measurement of nitrous oxide in gaseous and liquid phase was performed by Teledyne data logger and Unisense microsensor. Measurements during 4 months resulted in assessment of nitrous oxide emission tendency dependent on aeration system. The result from reactor R1 showed that 1.0-2.4% of N-load was emitted as N2O to the atmosphere, and 0.05-0.28% was released as dissolved N2O in outgoing water. Regarding reactor R2 tendency of nitrous oxide production is similar. Estimated emission of N2O in gaseous phase in reactor R2 is 1.4-2.0% of nitrogen load and 0.02-0.39% in liquid phase. All gathered results are shown in the appendix of the paper.
45

Application of Partial Nitritation/Anammox Process for Treatment of Wastewater with High Salinity.

Zhang, Xin January 2012 (has links)
The combination of partial nitritation and anaerobic ammonium oxidation (Anammox) is a composting way to remove the nitrogen in the wastewater. In this article the analysis was made to investigate how the salinity in the wastewater affects the process. Two strategies of salt concentration increase were tested in two reactors. The physical, chemical parameters and the activity of the bacteria in the reactors were monitored. The results of two strategies were compared and the reactor with less salt in each period showed higher bacteria activities and efficiency. Finally the outlook for the future research was made.
46

Application of on-line measurements and activity tests for the controlling and monitoring of the Nitritation/Anammox process.

Małoszewski, Kamil January 2013 (has links)
Anammox process is continuously tested in order to obtain knowledge about its application in the main stream of sewage. The aim of this study is to improve the controlling and monitoring of the Nitritation/Anammox process by applying on-line measurement of physical parameters and activity tests of different groups of bacteria. Additionally, the concentration of ammonia in inflow was reduced to test the reaction of bacteria to a sudden change in the conditions which may occur in wastewater treatment plants. After five months of tests, favourable results were obtained. Achieved removal of NH4-N was good. On-line measurements proved to be an effective tool to monitor the process. This may show the way for further research and ultimately leading to an effective implementation of the process for the treatment of the main stream of wastewater.
47

Evaluation of Deammonification process operated at low temperatures.

Rajkowski, Mariusz January 2012 (has links)
Anammox process is happening to be in the center of interest for several years. Implementing partial nitrification/Anammox process into main stream of wastewater would result in a great improvement of sustainable technologies for reducing nitrogen in environment. However, Great chalange fo Anammox bacteria in main stream is the low temperature which is a strong inhibiting factor for them. In this study pilot-scale MBBR reactor was operated to investigate the influence of low temperatures in Anammox process. Two different phases operated at 13 and 16°C were investigated during five months. SAA, OUR and online measurements were used to observe process capacity in low temperatures. Deammonification process was found to be stable in 13°C. Moreover, Anammox bacteria capacity to convert nitrogen to nitrogen gas was found in even 5°C. Satisfactory results for Deammonification process in low temperatures may result in future application of Anammox process in full-scale plant for main stream of wastewater.
48

Biocathodes in Bioelectrochemical Systems

Kokabian, Bahareh 11 December 2015 (has links)
Microbial desalination cells (MDCs), a recent technological discovery, allow for simultaneous wastewater treatment and desalination of saline water with concurrent electricity production. The premise for MDC performance is based on the principles that bioelectrochemical (BES) systems convert wastewaters into treated effluents accompanied by electricity production and the ionic species migration (i.e. protons) within the system facilitates desalination. One major drawback with microbial desalination cells (MDCs) technology is its unsustainable cathode chamber where expensive catalysts and toxic chemicals are employed for electricity generation. Introducing biological cathodes may enhance the system performance in an environmentally-sustainable manner. This study describes the use of autothrophic microorganism such as algae and Anammox bacteria as sustainable biocatalyst/biocathode in MDCs. Their great potential for high valuable biomass production combined with wastewater treatment presents these systems as a viable option to replace expensive/unsustainable catalysts for oxygen production in MDCs. Since alga is a photosynthetic microorganism, the availability of light as well as the electron-donating anodic process may have significant effects on the biocathode performance. A series of experiments evaluating these effects proved that algae perform better under natural light/dark cycles and that higher COD concentrations do not necessarily improve the power density. Furthermore, three different process configurations of photosynthetic MDCs (using Chlorella vulgaris) were evaluated for their performance and energy generation potentials. Static (fed-batch, SPMDC), continuous flow (CFPMDC) and a photobioreactor MDC (PBMDC, resembling lagoon type PMDCs) were developed to study the impact of process design on wastewater treatment, electricity generation, nutrient removal, and biomass production and the results indicate that PMDCs can be configured with the aim of maximizing the energy recovery through either biomass production or bioelectricity production. In addition, the microbial community analysis of seven different samples from different parts of the anode chamber, disclosed considerable spatial diversity in microbial communities which is a critical factor in sustaining the operation of MDCs. This study provides the first proof of concept that anammox mechanism can be beneficial in enhancing the sustainability of microbial desalination cells to provide simultaneous removal of ammonium from wastewater and contribute in energy generation.
49

Partial Nitration/anammox process in the moving bed biofilm reactor operated at low temperatures

Sultana, Razia January 2014 (has links)
<p>QC 20140527</p>
50

An Integrated Field-Scale Assessment of Chloramine Dynamics, By-Product Formation, and Nitrification Modeling

Alexander, Matthew T. 30 September 2010 (has links)
No description available.

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