EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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Resultados da Pesquisa
Item Optimization and scale-up of an LED-illuminated microalgal photobioreactor for wastewater treatment.(2020) Silva, Ludymyla Marcelle Lima; Santiago, Aníbal da Fonseca; Castro, Ana Leticia Pilz de; Bastos, Leonardo de Souza; Periard, Lucas; Vassoler, FábioThe use of light-emitting diode (LED)-illuminated photobioreactors with microalgae has been extensively studied for wastewater treatment. Most studies have used isolated microalgae species; however, this practice does not match the reality of conditions in wastewater treatment plants. Operational conditions that promote greater growth of algal biomass and that remove pollutants most effectively are disputed in the literature. In this context, LED-illuminated photobioreactors with microalgae were evaluated using multivariate analysis in order to optimize removal of pollutants (nitrogen, phosphorus, and carbonaceous organic matter). Three variables were evaluated: operating time, LED wavelength, and luminous flux intensity. A microalgae consortium was used in the photobioreactor. In addition to the LED-illuminated photobioreactors, control photobioreactors illuminated by sunlight were also operated. Using the results obtained in the optimization, a scaled-up reactor approximately 8.5 times larger in volume was operated to evaluate if the behavior would be maintained. The best operational conditions for the removal of pollutants were observed in LED-illuminated photobioreactors operated under a light intensity of 700 μmol·m 2 s 1 for 15 days. Under these conditions, it was possible to remove 89.97% of carbonaceous organic matter, 86.50% of nitrogen, and 30.64% of phosphorus. The scaled-up photobioreactor operated with similar performance.Item Desempenho energético e tratamento de água residuária em fotobiorreator contínuo iluminado artificialmente.(2020) Oliveira, Raquel Gomes de; Vassoler, Fábio; Santiago, Aníbal da FonsecaThe use of Light Emitting Diodes (LEDs) as a light source has several advantages: high efficiency, long lifetime and low energy consumption. LEDs can be obtained in the lighting of photobioreactors for the treatment of wastewater. Cleaning removing organic matter, nutrients and pathogens. Most of the researches found in the literature make use of laboratory scale photobioreactors (1L) generally and operated in batch. Despite the low energy consumption of LEDs, its use for continuous photobioreactors is questioned, since the energy performance for these systems has not yet been evaluated. Microalgae are cultivated in photobioreactors and, in addition to promoting wastewater treatment, their biomass can be reused to generate different bioproducts. This research evaluated the efficiency of an open LED-illuminated photobioreactor, simulating the operation of a High Rate Lagoon (LAT) in the treatment of synthetic wastewater and also evaluated the energy aspect as a function of artificial lighting. The system was operated in continuous regime under hydraulic detention time (TDH) of 7 days and luminous intensity of 815 μE.m-2.s-1. The microalgae biomass productivity was 6.80 ± 1.9 g.d-1.m-2 and the net oxygen production was 0.83 g.L-1. The stability and efficiency system in the removal of organic matter, represented by the Chemical Oxygen Demand (COD), with 90.3 ± 1.7% of removal. However, high values of energy consumption indicators for wastewater treatment were obtained, with 368.8 kWh / kg COD removed, 287 kWh.m-3 and 51.66 kWh (hab.d) -1.Item Algae/bacteria consortium in high rate ponds : influence of solar radiation on the phytoplankton community.(2015) Assemany, Paula Peixoto; Calijuri, Maria Lúcia; Couto, Eduardo de Aguiar do; Souza, Mauro Henrique Batalha de; Silva, Nirlane Cristiane; Santiago, Aníbal da Fonseca; Castro, Jackeline de SiqueiraUsing multivariate statistical tools, the composition of the phytoplankton community was related to the characteristics of the domestic sewage used as culture medium in three high rate ponds (HRPs) submitted to different solar radiation levels. A total of 32 genera of phytoplankton were identified in the ponds; the class Chlorophyceae was the most abundant during the entire sampling period, with a larger number of individuals of the genus Desmodesmus in the summer and fall, and of the genus Chlorella in the winter and spring. The lowest occurrence of phytoplankton was observed in the fall, with behavior similar to the evolution of solar radiation throughout the year. Blocking over 30% of the solar radiation allowed for less variability of the phytoplankton community and favored the growth of biomass with higher density of individuals, as well as higher concentrations of chlorophyll-a and dissolved oxygen. On the other hand, the pond with 80% of shading presented the lowest mean density of organisms; from the perspective ofwastewater treatment, however, it can be considered the most efficient in terms of organic matter and nutrient removal. According to the regression analysis, the algal biomass in HRPs can be maximized mostly if we consider the positive effect of carbon and phosphorus and the limiting effect of nitrogen and non-biodegradable organic load. For the conditions evaluated in this study, the photoinhibition phenomenon was not observed. Other aspects such as competition with other microorganisms for space and nutrients, or predation by zooplankton, seemed to be more significant for the growth and development of algal biomass.Item Influence of solar radiation on nitrogen recovery by the biomass grown in high rate ponds.(2015) Couto, Eduardo de Aguiar do; Calijuri, Maria Lúcia; Assemany, Paula Peixoto; Tango, Mariana Daniel; Santiago, Aníbal da FonsecaThe objective of this study was to assess the effect of different solar radiation intensities on nitrogen assimilation by a consortium of bacteria and microalgae grown in pilot scale high rate ponds (HRP) treating domestic wastewater. The HRPs received effluent from an anaerobic reactor. The experiment was carried out under tropical climate conditions. A total of five HRPs were used; four of them were covered with shading screens that blocked 9%, 18%, 30% and 60% of the incident solar radiation. Nitrification was the main process for nitrogen removal/transformation in all HRPs and the volatilization of ammonia nitrogen occurred in levels below the expected range due to low pH values. The organic nitrogen concentration followed the same trend of the biomass production, but no statistical difference was found between the 60% screen HRP and the uncovered one, which led to the conclusion that the intensity of the photosynthetically active radiation does not compromise nitrogen assimilation, since the bacterial biomass may develop in conditions that are unfavorable to the growth of microalgae. Moreover, other aspects, such as CO2 addition, may reduce nitrogen losses by volatilization and denitrification, as well as contribute to recover this nutrient through biomass assimilation.