Centro de Ciências Exatas e Tecnológicas
URI permanente desta comunidadehttps://locus.ufv.br/handle/123456789/9791
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Resultados da Pesquisa
Item Identificação de áreas para implantação de usina de reciclagem de resíduos da construção e demolição com uso de análise multicritério(Ambiente Construído, 2018-01) Bohnenberger, José Carlos; Pimenta, João Francisco de Paula; Abreu, Marcos Vinicius Sanches; Comini, Ulisses Bifano; Calijuri, Maria Lúcia; Moraes, Ana Paula de; Pereira, Isaias da SilvaA construção civil é responsável por um elevado consumo de recursos naturais e também pela geração de uma grande quantidade de resíduos de construção e de demolição (RCD). Uma alternativa para o gerenciamento sustentável dos RCDs é a reciclagem para uso na própria construção civil, o que permite a redução da demanda de recursos naturais e dos custos, além de amenizar o impacto gerado pela disposição inadequada desses resíduos no meio ambiente. Diante desse cenário, o presente trabalho tem como objetivo analisar e selecionar áreas para a implantação de uma usina de reciclagem de RCD no Município de Viçosa, MG. Foram utilizadas técnicas de sistemas de informações geográficas (SIG) que permitiram avaliar áreas alternativas por meio da aplicação da análise multicritério, tendo sido selecionadas 23 áreas possíveis para implementação da unidade. A análise complementar com visitação in loco permitiu a seleção de 4 áreas consideradas mais adequadas por apresentarem acesso facilitado, baixos valores imobiliários, ausência de edificações ou uso futuro predefinido. A metodologia adotada se mostrou apropriada para auxiliar na tomada de decisão e na diminuição do tempo necessário para a escolha de áreas destinadas à reciclagem de RCD, podendo ser replicada em outros municípios.Item Microalgae biofilm in soil: Greenhouse gas emissions, ammonia volatilization and plant growth(Science of The Total Environment, 2017-01-01) Castro, Jackeline de Siqueira; Calijuri, Maria Lúcia; Assemany, Paula Peixoto; Cecon, Paulo Roberto; Assis, Igor Rodrigues de; Ribeiro, Vinícius JoséMicroalgal biofilm in soils represents an alternative fertilization method for agricultural sustainability. In the present study, greenhouse gas emission, soil ammonia volatilization, and the growth of Pennisetum glaucum were evaluated under the effect of a microalgal biofilm, commercial urea, and a control (without application of a nitrogen source). CH4 emissions were equal for the three treatments (p > 0.05). CO2 emissions significantly increased in microalgal biofilm treatment (p < 0.01), which was also responsible for the highest N2O emissions (p < 0.01). The ammonia (NNH3) volatilization losses were 4.63%, 18.98%, and 0.82% for the microalgal biofilm, urea, and control treatments, respectively. The main differences in soil characteristics were an increase in nitrogen and an increase in cation exchange capacity (p < 0.01) caused by the algal biomass application to the soil. The soil organic matter content significantly differed (p < 0.05) among the three treatments, with the microalgal biofilm treatment having the greatest increase in soil organic matter. Significant differences were observed for shoot dry matter mass and nitrogen content in the plants from both treatments where nitrogen sources were applied. All treatments differed from each other in leaf dry matter mass, with the urea treatment increasing the most. Chlorella vulgaris was the dominant microalgal specie in the soil.Item A model-based site selection approach associated with regional frequency analysis for modeling extreme rainfall depths in Minas Gerais state, southeast Brazil(Stochastic Environmental Research and Risk Assessment, 2018-02) Calijuri, Maria Lúcia; Assis, L. C.; Silva, D. D.; Rocha, E. O.; Fernandes, A. L. T.; Silva, F. F.Extreme rainfall data are usually scarce due to the low frequency of these events. However, prior knowledge of the precipitation depth and return period of a design event is crucial to water resource management and engineering. This study presents a model-based selection approach associated with regional frequency analysis to examine the lack of maximum daily rainfall data in Brazil. A generalized extreme values (GEV) distribution was hierarchically fitted using a Bayesian approach and data that were collected from rainfall gauge stations. The GEV model parameters were submitted to a model-based cluster analysis, resulting in regions of homogeneous rainfall regimes. Time-series data of the individual rainfall gauges belonging to each identified region were joined into a new dataset, which was divided into calibration and validation sets to estimate new GEV parameters and to evaluate model performance, respectively. The results identified two distinct rainfall regimes in the region: more and less intense rainfall extremes in the southeast and northwest regions, respectively. According to the goodness of fit measures that were used to evaluate the models, the aggregation level of the parameters in clustering influenced their performance.Item Algae/bacteria consortium in high rate ponds: Influence of solar radiation on the phytoplankton community(Ecological Engineering, 2015-04) 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 of wastewater 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 Effects on runoff caused by changes in land cover in a brazilian southeast basin: evaluation by HEC-HMS and HEC-GEOHMS(Environmental Earth Sciences, 2018-03-23) Santos, Vitor Juste dos; Moraes, Thalita Costa de; Calijuri, Maria Lúcia; Torres, Fillipe Tamiozzo PereiraThe Southeast Region of Brazil has undergone major changes in land cover, especially after the eighteenth century. It is currently the most populous region of the country, highly urbanized, with a high degree of industrial and agricultural development. Extensive areas of native vegetation have been replaced by pastures, crops and urban areas, which have increased runoff, causing environmental, economic and social problems related to flooding. The objective of this study was to analyze effects of land cover changes in a basin with rural and urban characteristics on the flow of its main river. Hydrological data, orbital images, soils and topographical maps were used for this purpose. Based on the land cover maps for the years of 1989, 2001 and 2015, and on the hydrological modeling performed using the Hec-HMS 4.1 software, scenarios were simulated and showed that the land cover changes in this basin significantly affect the flow behavior of the main river. The simulated runoff was calibrated using the data observed in the field during 2001, and validation was performed using data from 1989. After the calibration and validation processes, a scenario was simulated where the rainiest month of the whole series measured by the rainfall station (during December 1989) acted on the land cover of 2015. There was an increase in pasture areas and impermeable spaces in the basin, which caused a decrease in infiltration and an increase in surface runoff, and also an increase in the flow peaks and a reduction in the time of concentration. The hydrological modeling was satisfactory, since the uncertainties related to the simulation were low.Item Microalgal biomass production and nutrients removal from domestic sewage in a hybrid high-rate pond with biofilm reacto(Ecological Engineering, 2017-09) Assis, Letícia Rodrigues de; Calijuri, Maria Lúcia; Couto, Eduardo de Aguiar do; Assemany, Paula PeixotoIn this study, biomass production and domestic sewage treatment in hybrid systems under bacterial-microalga consortia were assessed. Biomass was grown suspended in the growth media of high-rate ponds (HRPs) and attached in biofilm reactors (BRs). These hybrid systems were operated with and without the addition of CO2 (HS2 and HS1, respectively) in the HRP growth media. The performances of these systems were compared with that of a conventional HRP with CO2 supplementation. Regarding sewage treatment with microalgae and bacteria consortia, the three systems showed no significant differences in the removal of organisms associated with faecal contamination, organic matter and most nutrients. However, nitrate levels were increased in the hybrid systems due to the presence of BRs. There were no differences in algal biomass production among the three systems, which remained in the 0.6–0.7 g m−2 range. HS1 showed the highest total biomass production of 101.31 g m−2 at a production rate of 6.79 g m−2 day−1. The BR of HS1 was able to supply the necessary CO2 and therefore no additional gas supplementation was required. This result indicates that a conventional HRP with CO2 supplementation can be replaced by a hybrid system with biofilm reactor, with additional advantages of resources saving, operational simplicity and easier harvesting.Item Microalgal biomass production and nutrients removal from domestic sewage in a hybrid high-rate pond with biofilm reactor(Ecological Engineering, 2017-09) Assis, Letícia Rodrigues de; Calijuri, Maria Lúcia; Couto, Eduardo de Aguiar do; Assemany, Paula PeixotoIn this study, biomass production and domestic sewage treatment in hybrid systems under bacterial-microalga consortia were assessed. Biomass was grown suspended in the growth media of high-rate ponds (HRPs) and attached in biofilm reactors (BRs). These hybrid systems were operated with and without the addition of CO2 (HS2 and HS1, respectively) in the HRP growth media. The performances of these systems were compared with that of a conventional HRP with CO2 supplementation. Regarding sewage treatment with microalgae and bacteria consortia, the three systems showed no significant differences in the removal of organisms associated with faecal contamination, organic matter and most nutrients. However, nitrate levels were increased in the hybrid systems due to the presence of BRs. There were no differences in algal biomass production among the three systems, which remained in the 0.6–0.7 g m−2 range. HS1 showed the highest total biomass production of 101.31 g m−2 at a production rate of 6.79 g m−2 day−1. The BR of HS1 was able to supply the necessary CO2 and therefore no additional gas supplementation was required. This result indicates that a conventional HRP with CO2 supplementation can be replaced by a hybrid system with biofilm reactor, with additional advantages of resources saving, operational simplicity and easier harvesting.Item Influence of solar radiation on nitrogen recovery by the biomass grown in high rate ponds(Ecological Engineering, 2015-08) 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.Item Hydrothermal liquefaction of biomass produced from domestic sewage treatment in high-rate ponds(Renewable Energy, 2018-04) Couto, Eduardo Aguiar; Pinto, Filomena; Varela, Francisco; Reis, Alberto; Costa, Paula; Calijuri, Maria LúciaThis study evaluates the application of biomass produced from the treatment of domestic sewage in high-rate ponds (HRPs) as feedstock for the production of bio-oil via hydrothermal liquefaction (HTL). The effects of reaction time, temperature, and biomass/water ratio on the yield of bio-oil were assessed. In addition, a balance of carbon and nitrogen among the products (bio-oil, aqueous phase, solid residue, and gas) was carried out, in order to evaluate the quality of the bio-oil and possibilities for increasing value from the byproducts. In a 15-min operation at 300 °C with biomass/water ratio of 1/10 (w.w−1), the bio-oil yield was of 44.4% (Dry Ash Free - daf-basis). Under every condition tested, the solid residue was the most abundant byproduct, mostly due to the high ash content in the biomass. The minimum nitrogen recovery in the bio-oil was 57%, obtained in the operation at 275 °C, which is considered the main disadvantage of the process. The use of biomass directly after its production may result in an excessive consumption of energy due to the high water content. However, the need for drying is reduced when compared to other microalgal-based bioenergy production processes, potentially achieving a positive energy balance in the HTL.Item Energetic valorization of algal biomass in a hybrid anaerobic reactor(Journal of Environmental Management, 2018-01-04) Assemany, Paula; Marques, Isabel de Paula; Calijuri, Maria Lúcia; Silva, Teresa Lopes da; Reis, AlbertoThis study evaluated the operation of a hybrid anaerobic reactor fed with algal biomass cultivated in effluent from the brewery industry. Three stages of operation were distinguished during the 72 days of semi-continuous functioning of the reactor: Stage 1 (S1), in which algal biomass was used as substrate; Stage 2 (S2), in which 10% (v/v) of the algal biomass was substituted by olive mill wastewater (OMW); and Stage 3 (S3), in which algal biomass was heat pre-treated. During S1, a loss of solids was observed, with an increment of organic matter in the outlet. The substitution of 10% of the volume of algal biomass by OMW tripled the methane productivity obtained in the previous stage by digestion of pure algal biomass. Heat pre-treatment was not efficient in rupturing the cell wall, and consequently did not have any effect on the increase in biogas production. The complementarity of substrates in the assessed conditions led to better results than the pre-treatment of the algal biomass.