Centro de Ciências Exatas e Tecnológicas

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Water quality prediction using the QUAL2Kw model in a small karstic watershed in Brazil
(Acta Limnologica Brasiliensia, 2010-10) Camargo, Rodrigo de Arruda; Calijuri, Maria Lúcia; Santiago, Aníbal da Fonseca; Couto, Eduardo de Aguiar de; Silva, Marcos Dornelas Freitas Machado e
The Tancredo Neves International Airport (TNIA) complex is situated in Brazil's Fidalgo watershed. Since its construction, the TNIA complex has attracted urban development, leading to expansion of the complex and occupation of the surrounding area. However, this area lacks basic infrastructure such as wastewater treatment facilities. This paper had the objectives of calibrating and validating a water quality prediction model and of assessing the capacity of small karstic watersheds to assimilate non-point source pollutant loads. We used the QUAL2Kw model for modeling the water quality. We performed model calibration for the rainy period then validated the results for the dry period. The model adequately represented the physical, chemical, and hydraulic aspects of the Fidalgo watershed. The pH, EC, TDS, TP, alkalinity and E. coli presented the closest simulation values for the rainy period. For the dry period, the best simulations were obtained for pH, EC, TDS, TP, and alkalinity. We concluded that the calibration and validation periods had similar RMSE values for flow rate, TDS and DOC. The differences were greater for pH, EC, NO3, TP, and E. coli. The lowest dissolved oxygen contents obtained during the calibration and validation periods were 5.4 and 4.7 mg.L-1, respectively, both of which are higher than the minimum of 4.0 mg.L-1 established by the USEPA for the conservation of aquatic communities, but lower than the minimum of 5.0 mg.L-1established by the Brazilian CONAMA 357. The upper limits for biochemical oxygen demand and total N and P can be met as long as the respective loads increase by no more than 0.361 kg.d-1 O2, 0.022 kg.d-1 N, and 0.010 kg.d-1 P, according to USEPA and 0.361 kg.d-1 O2 and 0.012 kg.d-1 P according to CONAMA 357. The conservation of the water resources in this region should therefore consider the adoption of preventive measures such as protecting exposed soils and decreasing the nutrient influx from agricultural and livestock activities.
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 Silva
A 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.
Soil application of microalgae for nitrogen recovery: A life-cycle approach
(Journal of Cleaner Production, 2019-02-20) Souza, Mauro Henrique Batalha de; Calijuri, Maria Lúcia; Assemany, Paula Peixoto; Castro, Jackeline de Siqueira; Oliveira, Anna Carolina Martins de
The application of algal biomass in the soil represents an alternative of efficient use of fertilizers. In the present study, the environmental impacts generated by the application of 1 kg of nitrogen from the algal biomass (biofertilizer) were analyzed through life cycle analysis. Nitrogen was recovered from a meat processing industry effluent in a high-rate algal pond. Impacts related to the entire biofertilizer chain were mainly impacting on climate changes (115 kgCO2eq). Other categories (particle formation, terrestrial acidification, freshwater eutrophication and freshwater ecotoxicity) were not very representative. Biomass cultivation was the most critical step regarding energy and time consumption. On the other hand, the use of effluent as the culture medium for microalgae growth reduced impact categories, such as freshwater eutrophication. Results showed that microalgae cultivation and harvesting steps need to be technologically developed, especially when compared to a conventional fertilizer already established in the market. In order to make microalgae biofertilizer environmental advantageous, alternatives should be beforehand: i) the use of photovoltaic energy instead of hydropower energy; ii) the use of a nitrogen richer effluent; iii) and the consideration of an environmental compensation for the treatment of effluent can be accounted for, disregarding the biomass production stage.
Using atmospheric emissions as CO2 source in the cultivation of microalgae: Productivity and economic viability
(Journal of Cleaner Production, 2019-04) Assis, Tamires Condé de; Calijuri, Maria Lúcia; Assemany, Paula Peixoto; Pereira, Alexia Saleme Aona de Paula; Martins, Márcio Arêdes
This study approached the use of atmospheric emissions as a source of carbon for the cultivation of microalgae in high rate ponds (HRPs), continuously fed with domestic sewage pre-treated in a septic tank. To do so, two HRPs were used: one had CO2 at a concentration of 99.9% (HRP 1), and the other had gas from the combustion of gasoline (HRP 2). Biomass yield, sewage treatment efficiency and the economic viability of using these two sources were assessed. The results showed that the CO2 source did not influence the domestic sewage treatment or the yield and biochemical composition of biomass, since there was no statistical difference (p < 0.05) between the values measured for both ponds. The mean yield values were 6.00 and 6.12 g m−2 day−1, respectively for the HRPs 1 and 2. As for the mean concentrations of ammonia nitrogen and the percentages of removal of chemical oxygen demand (COD), they were in the average for both HRPs (26.4 mg L−1 and 31.2%). The negative Net Present Values (NPV) showed that in this study the investments for installing external CO2 sources are not economically viable for any of the two studied sources, when the biomass produced in the HRPs is used for the production of biofuels and as source of protein for animal feeding. The initial investments, allied to the prices of the biomass, were the factors that mostly influenced the economic analysis, contributing to the lack of attractiveness in this scale. Despite this, the use of atmospheric emissions along with domestic sewage as a cultivation medium means the biomass produced in this study has less environmental impact when compared to similar biomasses.
Evaluation of the influence of natural and antrhopogenic processes on water quality in karstic region
(Water, Air, & Soil Pollution, 2012-06) Calijuri, Maria Lúcia; Couto, Eduardo de Aguiar do; Santiago, Aníbal da Fonseca; Camargo, Rodrigo de Arruda; Silva, Marcos D. F. M. e
This paper presents a comprehensive study on the quality of surface and groundwater in an environmentally sensitive karstic watershed strongly pressed by urban growth. The objective of the study was to assess the integrated effects of human activities and natural characteristics of karstic environments on the quality of surface and groundwater using multivariate statistical techniques. Data from 18 physical, chemical, and microbiological water quality variables obtained throughout a hydrological year were analyzed using principal components analysis (PCA) and cluster analysis. The PCA was carried out individually for surface water and groundwater. Our goal was to study the behavior of the water quality variables at each of these systems, as well as to infer the importance of these variables on the dynamics of the water resources in the region. Our results for surface water showed that the 18 original variables could be reduced to five principal components which together accounted for 69% of the total variation in the data, whereas for groundwater, 70% of the total variation in the data was explained by five principal components. In order to evaluate the impacts of anthropic activities on the water quality at the monitoring locations, the cluster analysis was applied to the ten sampling points. The analysis identified five clusters, two of which are formed by points with low contamination levels and three where the anthropic interference is noticeable. The results suggest the existence of specific contamination sources in many points, including in the groundwater, and highlight the natural vulnerability of the karstic environments.
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 José
Microalgal 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.
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.
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 Siqueira
Using 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.
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 Pereira
The 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.
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 Peixoto
In 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.

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