Browsing by Author "Lima, Diego Roberto de Sousa"

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    Evaluating arsenic and manganese removal from water by chlorine oxidation followed by clarification.
    (2015) Pires, Viviane das Graças Rodrigues; Lima, Diego Roberto de Sousa; Aquino, Sergio Francisco de; Libânio, Marcelo
    This paper investigates the simultaneous removal of arsenic [As(V) or As(III)] and manganese [Mn(II)] from natural waters of low and high turbidity by clarification (with polyaluminum chloride and aluminum sulfate as primary coagulants) associated or not with chlorine pre-oxidation. The results showed that the clarification process exhibited low Mn(II) removal, that varied from 6% to 18% and from 19% to 27% for natural waters of low and high turbidity, respectively. The use of chlorine as pre-oxidant increased Mn(II) removal up to 77% and was associated with the formation of birnessite. Regarding As(V) removal by clarification, particularly for high turbidity water, a concentration lower than that established by the National Drinking Water Quality Standards (10 μg.L-1) was achieved in almost all tests. Oxidation preceding the clarification led to AsIII removal efficiencies from 80% to 90% for both coagulants and types of water
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    Evaluation of soluble microbial products and aromatic amines accumulation during a combined anaerobic/aerobic treatment of a model azo dye.
    (2015) Baeta, Bruno Eduardo Lobo; Lima, Diego Roberto de Sousa; Silva, Silvana de Queiroz; Aquino, Sergio Francisco de
    The current work have investigated the accumulation of soluble microbial products (SMP) and aromatic amines in anaerobic reactors followed by aerobic reactors (Ar1 or Ar2) during the azo dye Remazol Golden Yellow RNL (RGYRNL) degradation. One anaerobic reactor (An2) contained powdered activated carbon (PAC) in its interior, while another one (An1) was used as control. The results have shown the efficiency of COD and color removal in the combined system An1/Ar1 was higher than 70%, while in the An2/ Ar2 system the COD and color removal was above 85% and 90%, respectively, in all three operational phases. The aerobic reactors were capable of removing most of the residual organic matter, volatile fatty acid (VFA) and aromatic amines, generated during the anaerobic step, and the presence of PAC inside reactor An2 ensured higher operational stability since it minimized the toxic effects caused by anaerobic degradation byproducts. The presence of PAC contributed to reduce SMP accumulation in phases 2 (CODSMP = 32.40 mg/L) and 3 (CODSMP = 21.61 mg/L) and enhanced the effluent quality.
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    Influence of different thermal pretreatments and inoculum selection on the biomethanation of sugarcane bagasse by solid-state anaerobic digestion : a kinetic analysis.
    (2018) Lima, Diego Roberto de Sousa; Herrera Adarme, Oscar Fernando; Baeta, Bruno Eduardo Lobo; Gurgel, Leandro Vinícius Alves; Aquino, Sergio Francisco de
    The present study investigated the potential of UASB inoculum, by itself or mixed to nitrogenous residue (fresh bovine manure – FBM) or to adapted microorganisms (bovine rumen – BR), for biomethanation of raw and pretreated sugarcane bagasse (SB) by solid-state anaerobic digestion. The influence of autohydrolysis and organosolv pretreatment conditions on the efficiency of biomethanation process was also evaluated by means of kinetic parameters. Akaike Information Criterion was used to statistically evaluate methane production, and the multi-stage model exhibited the highest fit among the models tested. FBM addition resulted in improvements in the C/N ratio, higher yield (143.3NLCH4 kgVS −1) and higher rate constant (3.05NLCH4 kgVS −1day−1) for CH4 production from raw SB without any lag phase when compared to UASB inoculum itself which exhibited 5.6 days of lag phase. The FBM also led to a better inoculum adaptation to substrates which contained inhibitors such as xylooligomers and lignin fragments, and had lower C5 sugar content.
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    Influence of the applied organic load (OLR) on textile wastewater treatment using submerged anaerobic membrane bioreactors (SAMBR) in the presence of redox mediator and powdered activated carbon (PAC).
    (2016) Baeta, Bruno Eduardo Lobo; Lima, Diego Roberto de Sousa; Silva, Silvana de Queiroz; Aquino, Sergio Francisco de
    This paper evaluated the treatment of textile wastewater in submerged anaerobic membrane bioreactors (SAMBR) operated on a bench scale. Particularly, the influence of operational conditions, such as the applied organic rate (OLR) and the dilution factor (for toxicity attenuation) of the textile wastewater, was evaluated on color and organic matter removal. In addition, the effect of powdered activated carbon (PAC) on SAMBR-1 and the addition of yeast extract (source of the redox mediator riboflavin) were also investigated. The results showed that reducing the textile wastewater dilution factor from 10× (phase 1) to 4× (phase 2) and 0× (no dilution) decreased the COD and color removal efficiencies in both SAMBRs, probably due to an increase in the toxic load. Nevertheless, PAC adsorbed toxic compounds found in the textile wastewater and helped biomass acclimatization, which led to higher COD and color removal efficiencies in SAMBR-1. The presence of yeast extract enhanced color removal efficiencies 3-fold in both SAMBRs when they were fed with undiluted textile wastewater.
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    Optimization of sugarcane bagasse autohydrolysis for methane production from hemicellulose hydrolyzates in a biorefinery concept.
    (2016) Baeta, Bruno Eduardo Lobo; Lima, Diego Roberto de Sousa; Herrera Adarme, Oscar Fernando; Gurgel, Leandro Vinícius Alves; Aquino, Sergio Francisco de
    This study aimed to optimize through design of experiments, the process variables (temperature – T, time – t and solid-to-liquid ratio – SLR) for sugarcane bagasse (SB) autohydrolysis (AH) to obtain hemicellulose hydrolyzates (HH) prone to anaerobic digestion (AD) and biochemical methane production (BMP). The results indicated that severe AH conditions, which lead to maximum hemicelluloses dissolution and sugar content in the HH, were not the best for BMP, probably due to the accumulation of toxic/recalcitrant compounds (furans and lignin). Mild AH conditions (170 _C, 35 min and SLR = 0.33) led to the highest BMP (0.79 Nm3 kg TOC_1), which was confirmed by the desirability tool. HH produced by AH carried out at the desired condition DC2 (178.6 _C, 43.6 min and SLR = 0.24) showed the lowest accumulation of inhibitory compounds and volatile fatty acids (VFA) and highest BMP (1.56 Nm3 kg TOC_1). The modified Gompertz model best fit the experimental data and led to a maximum methane production rate (R) of 2.6 mmol CH4 d_1 in the best condition.
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    Remoção de fármacos e desreguladores endócrinos de águas naturais por clarificação associada à adsorção em carvão ativado em pó.
    (Programa de Pós-Graduação em Engenharia Ambiental. PROÁGUA, Pró-Reitoria de Pesquisa e Pós Graduação, Universidade Federal de Ouro Preto., 2013) Lima, Diego Roberto de Sousa; Aquino, Sergio Francisco de
    Microcontaminantes emergentes tais quais os fármacos e os desreguladores endócrinos encontram-se em águas superficiais em baixas concentrações (ng/L a μg/L), mas que ainda assim tem o potencial que afetar adversamente a biota aquática e a saúde humana. Neste trabalho foram avaliadas as eficiências do tratamento por clarificação (coagulação, floculação e sedimentação) em águas naturais de baixa e elevada turbidez empregando o cloreto de polialumínio (PAC) e sulfato de alumínio (SA) como coagulante na presença e ausência de carvão ativado em pó (CAP) na remoção dos microcontaminantes bezafibrato (BZF), diclofenaco (DCF), sulfametoxazol (SMX), trimetoprima (TMP), etinilestradiol (EE2), bisfenol-A (BPA) e nonilfenol (NP); e de hormônios naturais como a estradiol (E2), estrona (E1) e estriol (E3). Foi possível concluir que a aplicação do PAC foi mais significativa na remoção dos microcontaminantes E1, E2 e EE2 quando comparado ao SA, independente das características das águas estudadas. Contudo, a aplicação de ambos os coagulantes nas águas estudadas proporcionou baixas eficiência de remoção dos microcontaminantes, variando de 10% a 38% para os estrogênios, e atingindo os maiores valores 71% para o sulfametoxazol. A aplicação do CAP concomitantemente aos coagulantes no tratamento por clarificação piorou a remoção dos microcontaminantes nas distintas águas estudadas, demonstrando haver competição entre os microcontaminantes e as espécies hidrolisadas do coagulante pelos sítios ativos do adsorvente. A aplicação do CAP (dose = 10mg/L, tempo contato de 13,5 a 23,5min) juntamente ao SA tornou o tratamento mais eficiente para a remoção do E1 (40%), E2 (33%) e EE2 (40%) independente das características das águas. Quando o coagulante foi o PAC, a adição de 10mg/L de CAP (tempo de contato de 8,5 a 13,5min) mostrou-se mais efetiva apenas na remoção de EE2 (52%) para ambas as águas de baixa e alta turbidez. Quando o CAP foi adicionado como pré-tratamento a eficiência de remoção dos microcontaminantes aumentou muito e a dose de 10mg/L no tempo de contato de 120min foi suficiente para remover de 34% a 99,9% dos microcontaminantes estudados.
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    Removal of pharmaceuticals and endocrine disruptor compounds from natural waters by clarification associated with powdered activated carbono.
    (2014) Lima, Diego Roberto de Sousa; Baeta, Bruno Eduardo Lobo; Libânio, Marcelo; Afonso, Robson José de Cássia Franco
    This work has evaluated the efficiency of two coagulants, aluminum sulfate (AS) and polyaluminum chloride (PACl), combined with the adsorption process using powdered activated carbon (PAC) on the removal of diclofenac (DCF), sulfamethoxazole (SMX), ethinylestradiol (EE2), estradiol (E2), estrone (E1), estriol (E3), and bisphenol-A (BPA) from low- and highturbidity waters. The results have shown that the concomitant application of PAC and either coagulant has worsened the removal efficiency for all pharmaceuticals and endocrine disruptors tested, which might have occurred due to the covering of adsorption sites by aluminum hydroxide particles. In this configuration (coagulation in the presence of PAC, 10 mg L−1), the best removal efficiency (∼40 %) was obtained for E1 and EE2 when AS was used as coagulant in contact times that varied from 13.5 to 23.5 min. When the coagulant was the PACl, contact times were lower (8.5 to 13.5 min) and the highest removal efficiency was observed for EE2 (∼52 %).When PAC was added as a pretreatment (before addition of coagulant), the removal e f f i c i e n cy was gr e a t l y i n c r eased f o r al l microcontaminants and the application of 2.5 mg L−1 of PAC with 120 min of contact led to removal efficiencies varying from 30 to 99.9 %.
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    Two-stage fractionation of sugarcane bagasse by autohydrolysis and glycerol organosolv delignification in a lignocellulosic biorefinery concept.
    (2017) Meighan, Brittany Nicole; Lima, Diego Roberto de Sousa; Cardoso, Wilson Junior; Baeta, Bruno Eduardo Lobo; Herrera Adarme, Oscar Fernando; Santucci, Beatriz Stangherlin; Pimenta, Maria Teresa Borges; Aquino, Sergio Francisco de; Gurgel, Leandro Vinícius Alves
    Bioethanol production from lignocellulose biomass offers a solution to current environmental challenges caused by fossil fuel energy resources, while satisfying the biorefinery concept. In this study, two-stage fractionation (autohydrolysis (AH) followed by glycerol organosolv delignification (GOD)) of sugarcane bagasse (SCB) was studied as a function of temperature, time, glycerol content and liquid-to-solid (LSR) ratio using experimental designs. The effect of three different AH pretreatment severities on delignification extents (DE) of the solid fractions were also evaluated. Scanning electron microscopy was used to examine the changes in the surface of SCB pretreated by AH. Energy balances of four fractionation conditions were estimated, and the use of pure and crude glycerol in GOD was evaluated based on DE and lignin contents. A DE of ∼64% was obtained at 210.3 °C, 40 min, LSR of 6.5 (v/w) and 80% (v/v) pure glycerol for GOD of SCB pretreated by AH at 175.8 °C, 49 min and LSR of 5.3 (v/w), which resulted in an energetic profitability (EP) of 141.48 MJ/kgSCB. The use of crude glycerol at 80% (v/v) under the same process conditions optimized for pure glycerol also proved to be feasible (DE of ∼64% and EP of 142.67 MJ/kgSCB), widening the possibilities for its direct use in GOD of SCB pretreated by AH in a 2G bioethanol integrated plant.
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    Use of multivariate experimental designs for optimizing the reductive degradation of an azo dye in the presence of redox mediators.
    (2014) Lima, Diego Roberto de Sousa; Baeta, Bruno Eduardo Lobo; Silva, Gilmare Antônia da; Silva, Silvana de Queiroz; Aquino, Sergio Francisco de
    The optimization of the anaerobic degradation of the azo dye Remazol golden yellow RNL was performed according to multivariate experimental designs: a 22 full-factorial design and a central composite design (CCD). The CCD revealed that the best incubation conditions (90% color removal) for the degradation of the azo dye (50 mg L–1) were achieved with 350 mg L–1 of yeast extract and 45 mL of anaerobic supernatant (free cell extract) produced from the incubation of 650 mg L–1 of anaerobic microorganisms and 250 mg L–1 of glucose. A first-order kinetics model best fit the experimental data (k = 0.0837 h–1, R2 = 0.9263).
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    Uso de fotorreatores UV para a remoção de diclofenaco, bezafibrato e etinilestradiol de esgoto tratado em sistema UASB - FBP.
    (2015) Faria, Eros de; Lima, Diego Roberto de Sousa; Xavier, Leandro Pablo dos Santos; Aquino, Sergio Francisco de; Afonso, Robson José de Cássia Franco; Chernicharo, Carlos Augusto de Lemos; Gomes, Rafaela de Paiva
    Este trabalho avaliou a remoção de diclofenaco (DCF), bezafibrato (BZF) e etinilestradiol (EE2) de efluentes de sistema UASB-FBP (reator anaeróbio de manta de lodo seguido de filtro biológico percolador) em fotorreatores UV de lâmpadas imersas (FRI) e emersas (FRE). Os resultados mostram que baixa eficiência de remoção de tais compostos foi obtida em ambos fotorreatores quando se utilizou baixo tempo de contato (~10 min) e baixa concentração inicial de fármacos (0,5 μg.L-1 para EE2, e 21 μg.L-1 para DCF e BZF). O aumento da concentração inicial de DCF (para 20 mg.L-1) e do tempo de contato (para 20 min) resultaram em aumento da eficiência de remoção (de 31 para 83% no FRI e de 36 para 86% no FRE), indicando que compostos dissolvidos presentes no efluente biológico afetaram adversamente a remoção de fármacos nos fotorreatores devido a competição pela radiação UV incidente.