Iolanda Cristina Silveira Duarte | UFSCar - Federal University of São Carlos (original) (raw)
Papers by Iolanda Cristina Silveira Duarte
![Research paper thumbnail of Corrigendum to “Anaerobic degradation of linear alkylbenzene sulfonate (LAS) in fluidized bed reactor by microbial consortia in different support materials” [Bioresource Technology 101 (2010) 5112–5122]](https://attachments.academia-assets.com/45851592/thumbnails/1.jpg)
](Bioresource Technology, 2010
Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorb... more Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorbed (mg) Degradation (%) R1 Activated carbon 331 12 96 34 86 R2 Expanded clay 306 51 83 0 83 R3 Glass beads 385 5 99 0.81 98.5 R4 Sand 385 6 98 0.92 98.2 0960-8524/$ -see front matter Ó
Current Research Topics in Applied Microbiology and Microbial Biotechnology, 2009
Microbial characterization of Linear Alkylbenzene Sulfonate degradation in fixed bed anaerobic re... more Microbial characterization of Linear Alkylbenzene Sulfonate degradation in fixed bed anaerobic reactor Lorena Lima de Oliveira*, 1, Iolanda Cristina Silveira Duarte1, and Maria Bernadete A. Varesche1 1 Department of Hydraulics and Sanitation, School of Engineering of São ...
Engenharia Sanitaria e Ambiental, 2010
Journal of the Brazilian Chemical Society, 2006
Este trabalho descreve o desenvolvimento e a validação de um método que usa cromatografia líquida... more Este trabalho descreve o desenvolvimento e a validação de um método que usa cromatografia líquida de alta eficiência para determinação de Alquilbenzeno Linear Sulfonado (LAS) em amostras de águas provenientes de reatores anaeróbios. O padrão de LAS aplicado foi ácido dodecilbenzeno sulfônico-sal sódico, que apresentou 4 picos principais no cromatograma, relacionados aos diferentes homólogos da cadeia alquílica linear. Diferentes condições cromatográficas foram testadas, tais como, fases estacionárias C-18, C-12 e C-8; detectores de ultravioleta e de fluorescência, composição da fase móvel e tempo de programação do gradiente de eluição. A melhor condição cromatográfica obtida foi com a coluna C-8, fase móvel: metanol/ perclorato de sódio 0,075 mol L -1 e detector de fluorescência. A validação deste método foi feita através das curvas de calibração de LAS, usando água e substrato sintético como solventes. O método foi validado com o objetivo de demonstrar sua precisão, linearidade, limite de detecção para cada homólogo e a sua precisão instrumental.
Journal of Environmental Management, 2009
Two horizontal-flow anaerobic immobilized biomass reactors (HAIB) were used to study the degradat... more Two horizontal-flow anaerobic immobilized biomass reactors (HAIB) were used to study the degradation of the LAS surfactant: one filled with charcoal (HAIB1) and the other with a mixed bed of expanded clay and polyurethane foam (HAIB2). The reactors were fed with synthetic substrate supplemented with 14 mg l À1 of LAS, kept at 30 AE 2 C and operated with a hydraulic retention time (HRT) of 12 h. The surfactant was quantified by HPLC. Spatial variation analyses were done to quantify organic matter and LAS consumption along the reactor length. The presence of the surfactant in the load did not affect the removal of organic matter (COD), which was close to 90% in both reactors for an influent COD of 550 mg l À1 . The results of a mass balance indicated that 28% of all LAS added to HAIB1 was removed by degradation. HAIB2 presented 27% degradation. Molecular biology techniques revealed microorganisms belonging the uncultured Holophaga sp., uncultured delta Proteobacterium, uncultured Verrucomicrobium sp., Bacteroides sp. and uncultured gamma Proteobacterium sp. The reactor with biomass immobilized on charcoal presented lower adsorption and a higher kinetic degradation coefficient. So, it was the most suitable support for LAS anaerobic treatment.
Journal of Environmental Management, 2013
Linear alkylbenzene sulfonate (LAS) is an anionic surfactant used in cleaning products, which is ... more Linear alkylbenzene sulfonate (LAS) is an anionic surfactant used in cleaning products, which is usually found in wastewaters. Despite the greater LAS removal rate related to a lower concentrations of volatile fatty acids (VFA), the influence of different ranges of VFA on LAS degradation is not known. LAS degradation was evaluated in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors at different ranges of VFA concentrations. The reactors were fed with a synthetic wastewater containing LAS (14 mg/L). A greater LAS removal rate (40e80%) was related to the lower and narrower range of acetic acid concentration (1e22 mg/L) in the EGSB reactor. In the UASB reactor, the acetic acid concentrations presented a wider range (2e45 mg/L), and some low LAS removal rates (around 20e25%) were observed even at low acetic acid concentrations (<10 mg/L). The high recirculation rate in the EGSB reactor improved substrate-biomass contact, which resulted in a narrower range of VFA and greater LAS removal rate.
International Journal of Hydrogen Energy, 2008
Clostridium sp a b s t r a c t Heat pre-treatment of the inoculum associated to the pH control wa... more Clostridium sp a b s t r a c t Heat pre-treatment of the inoculum associated to the pH control was applied to select hydrogen-producing bacteria and endospores-forming bacteria. The source of inoculum to the heat pre-treatment was from a UASB reactor used in the slaughterhouse waste treatment. The molecular biology analyses indicated that the microbial consortium presented microorganisms affiliated with Enterobacter cloacae (97% and 98%), Clostridium sp. and Clostridium acetobutyricum (96%), recognized as H 2 and volatile acids' producers. The following assays were carried out in batch reactors in order to verify the efficiencies of sucrose conversion to H 2 by the microbial consortium: 630.0 mg sucrose/L, (2) 1184.0 mg sucrose/L, (3) 1816.0 mg sucrose/L and (4) 4128.0 mg sucrose/L. The subsequent yields were obtained as follows: 15% (1.2 mol H 2 /mol sucrose), 20% (1.6 mol H 2 /mol sucrose), 15% (1.2 mol H 2 /mol sucrose) and 4% (0.3 mol H 2 /mol sucrose), respectively. The intermediary products were acetic acid, butyric acid, methanol and ethanol in all of the anaerobic reactors. ª (S.I. Maintinguer), varesche@sc.usp.br (M.B. Varesche). A v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / h e
International Journal of Hydrogen Energy, 2011
International Biodeterioration & Biodegradation, 2010
This study aimed to determine the efficiency of an anaerobic stirred sequencing-batch reactor con... more This study aimed to determine the efficiency of an anaerobic stirred sequencing-batch reactor containing granular biomass for the degradation of linear alkylbenzene sulfonate (LAS), a surfactant present in household detergent. The bioreactor was monitored for LAS concentrations in the influent, effluent and sludge, pH, chemical oxygen demand, bicarbonate alkalinity, total solids, and volatile solids. The degradation of LAS was found
Environmental Technology, 2013
The effect of a lipase-rich enzyme preparation produced by the fungus Penicillium sp. on solid-st... more The effect of a lipase-rich enzyme preparation produced by the fungus Penicillium sp. on solid-state fermentation was evaluated in two anaerobic bioreactors (up-flow anaerobic sludge blanket (UASB) and horizontal-flow anaerobic immobilized biomass (HAIB)) treating dairy wastewater with 1200 mg oil and grease/L. The oil and grease hydrolysis step was carried out with 0.1% (w/v) of the solid enzymatic preparation at 30 degrees C for 24 h. This resulted in a final concentration of free acids eight times higher than the initial value. The bioreactors operated at 30 degrees C with hydraulic retention times of 12 h (HAIB) and 20 h (UASB) for a period of 430 days, and had high chemical oxygen demand (COD) removal efficiencies (around 90%) when fed with pre-hydrolyzed wastewater. There was, however, an increase in the effluent oil and grease concentration (from values as low as 17 mg/L to values above 150 mg/L in the UASB bioreactor, and from 38-242 mg/L in the HAIB bioreactor), and oil and grease accumulation in the biomass throughout the operational period (the oil and grease content reached 1.7 times that found in the inoculum of the UASB bioreactor). The HAIB bioreactor gave better results because the support for biomass immobilization acted as a filter, retaining oil and grease at the entry of the bioreactor. The molecular analysis of the Bacteria and Archaea domains revealed significant differences in the microbial profiles in experiments conducted with and without the pre-hydrolysis step. The differences observed in the overall parameters could be related to the microbial diversity of the anaerobic sludge.
Brazilian Journal of Chemical Engineering, 2013
Brazilian Archives of Biology and Technology, 2011
In this work, the biological denitrification associated with anoxic oxidation of methane and the ... more In this work, the biological denitrification associated with anoxic oxidation of methane and the microbial diversity involved were studied. Kinetic tests for nitrate and nitrite (NO 2 -) removal and methane uptake were carried out in 100 mL batch reactors incubated in a shaker (40 rpm) at 30 o C. Denitrificant/methanotrophic biomass was taken from a laboratory scale reactor fed with synthetic nitrified substrates (40 mgN L -1 of NO 3 and subsequently NO 2 -) and methane as carbon source. Results obtained from nitrate removal followed a first order reaction, presenting a kinetic apparent constant (k NO3) ) of 0.0577±0.0057d -1 . Two notable points of the denitrification rate (0.12gNO 3 --N g -1 AVS d -1 and 0.07gNO 3 --N g -1 AVS d -1 ) were observed in the beginning and on the seventh day of operation. When nitrite was added as an electron acceptor, denitrification rates were improved, presenting an apparent kinetic constant (k NO2 ) of 0.0722±0.0044d -1 , a maximum denitrification rate of 0.6gNO 2 --N g -1 AVS d -1 , and minimum denitrification rate of 0.1gNO 2 --N g -1 AVS d -1 at the beginning and end of the test, respectively. Endogenous material supporting denitrification and methane concentration dissolved in the substrate was discarded from the control experiments in the absence of methane and seed, respectively. Methylomonas sp. was identified in the reactors fed with nitrate and nitrite as well as uncultured bacterium.
Bioresource Technology, 2013
Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the ... more Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the bioavailability of LAS based on the concentration of biomass in the system (1.3-16 g TS/L), the hydraulic retention time (HRT), which was operated at 6, 35 or 80 h, and the concentration of co-substrates as specific organic loading rates (SOLR) ranging from 0.03-0.18 g COD/g TVS.d. The highest degradation rate of LAS (76%) was related to the lowest SOLR (0.03 g COD/g TVS.d). Variation of the HRT between 6 and 80 h resulted in degradation rates of LAS ranging from 18% to 55%. Variation in the bioavailability of LAS resulted in discrete changes in the degradation rates (ranging from 37-53%). According to the DGGE profiles, the archaeal communities exhibited greater changes than the bacterial communities, especially in biomass samples that were obtained from the phase separator. The parameters that exhibited more influence on LAS degradation were the SOLR followed by the HRT.
![Research paper thumbnail of Corrigendum to “Anaerobic degradation of linear alkylbenzene sulfonate (LAS) in fluidized bed reactor by microbial consortia in different support materials” [Bioresource Technology 101 (2010) 5112–5122]](https://attachments.academia-assets.com/45851610/thumbnails/1.jpg)
](Bioresource Technology, 2010
Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorb... more Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorbed (mg) Degradation (%) R1 Activated carbon 331 12 96 34 86 R2 Expanded clay 306 51 83 0 83 R3 Glass beads 385 5 99 0.81 98.5 R4 Sand 385 6 98 0.92 98.2 0960-8524/$ -see front matter Ó
Bioresource Technology, 2009
The effect of a lipase-rich fungal enzymatic preparation, produced by a Penicillium sp. during so... more The effect of a lipase-rich fungal enzymatic preparation, produced by a Penicillium sp. during solid-state fermentation, was evaluated in an anaerobic digester treating dairy wastewater with 1200 mg of oil and grease/L. The oil and grease hydrolysis step was carried out with 0.1% (w/v) of solid enzymatic preparation at 30°C for 24 h, and resulted in a final free acid concentration eight times higher than the initial value. The digester operated in sequential batches of 48 h at 30°C for 245 days, and had high chemical oxygen demand (COD) removal efficiencies (around 90%) when fed with pre-hydrolyzed wastewater. However, when the pre-hydrolysis step was removed, the anaerobic digester performed poorly (with an average COD removal of 32%), as the oil and grease accumulated in the biomass and effluent oil and grease concentration increased throughout the operational period. PCR-DGGE analysis of the Bacteria and Archaea domains revealed remarkable differences in the microbial profiles in trials conducted with and without the pre-hydrolysis step, indicating that differences observed in overall parameters were intrinsically related to the microbial diversity of the anaerobic sludge.
Bioresource Technology, 2010
Linear alkylbenzene sulfonate (LAS) is an anionic surfactant widely used to manufacture detergent... more Linear alkylbenzene sulfonate (LAS) is an anionic surfactant widely used to manufacture detergents and found in domestic and industrial wastewater. LAS removal was evaluated in a horizontal anaerobic immobilized biomass reactor. The system was filled with polyurethane foam and inoculated with sludge that was withdrawn from an up flow anaerobic sludge blanket reactor that is used to treat swine wastewater. The reactor was fed with easily degradable substrates and a solution of commercial LAS for 313 days. The hydraulic retention time applied was 12 h. The system was initially operated without detergent and resulted to 94% reduction of demand. The mass balance in the system indicated that the LAS removal efficiency was 45% after 180 days. From the 109th day to the 254th day, a removal efficiency of 32% was observed. The removal of LAS was approximately 40% when 1500 mg of LAS were applied in the absence of co-substrates suggesting that the LAS molecules were used selectively. Microscopic analyses of the biofilm revealed diverse microbial morphologies and denaturing gradient gel electrophoresis profiling showed variations in the total bacteria and sulfate-reducing bacteria populations. 16S rRNA sequencing and phylogenetic analyses demonstrated that members of the order Clostridiales were the major components of the bacterial community in the last step of the reactor operation.
Biodegradation, 2008
The purpose of this work was to assess the degradation of linear alkylbenzene sulfonate (LAS) in ... more The purpose of this work was to assess the degradation of linear alkylbenzene sulfonate (LAS) in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor. The reactor was filled with polyurethane foam where the sludge from a sanitary sewage treatment was immobilized. The hydraulic detention time (HDT) used in the experiments was of 12 h. The reactor was fed with synthetic substrate (410 mg l(-1) of meat extract, 115 mg l(-1) of starch, 80 mg l(-1) of saccharose, 320 mg l(-1) of sodium bicarbonate and 5 ml l(-1) of salt solution) in the following stages of operation: SI-synthetic substrate, SII-synthetic substrate with 7 mg l(-1) of LAS, SIII-synthetic substrate with 14 mg l(-1) of LAS and SIV-synthetic substrate containing yeast extract (substituting meat extract) and 14 mg l(-1) of LAS, without starch. At the end of the experiment (313 days) a degradation of approximately 35% of LAS was achieved. The higher the concentration of LAS, the greater the amount of foam for its adsorption. This is necessary because the isotherm of LAS adsorption in the foam is linear for the studied concentrations (2 to 50 mg l(-1)). Microscopic analyses of the biofilm revealed diverse microbial morphologies, while Denaturing Gradient Gel Eletrophoresis (DGGE) profiling showed variations in the population of total bacteria and sulphate-reducing bacteria (SRB). The 16S rRNA gene sequencing and phylogenetic analyses revealed that the members of the order Clostridiales were the major components of the bacterial community in the last reactor operation step.
Page 257. Evaluation of the microbial diversity in anaerobic reactors fed with sucrose applied to... more Page 257. Evaluation of the microbial diversity in anaerobic reactors fed with sucrose applied to hydrogen production Sandra I. Maintinguer*, Bruna S. Fernandes, Iolanda Duarte, Kátia Saavedra, M. Bernadete A. Varesche Department ...
… Sanitaria e Ambiental, 2010
... a utilização de fungos, embora boa parte dos trabalhos encontrados seja com uso de biomassa m... more ... a utilização de fungos, embora boa parte dos trabalhos encontrados seja com uso de biomassa morta (FU; VIRARAGHAVAN, 2002; KUMARE; ABRAHAM, 2007 ... suporte foi removido com ajuda de pérolas de vidro e água destilada esterilizada a 121ºC a 1 atm, procedendo-se ...
Bioresource Technology, 2010
Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorb... more Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorbed (mg) Degradation (%) R1 Activated carbon 331 12 96 34 86 R2 Expanded clay 306 51 83 0 83 R3 Glass beads 385 5 99 0.81 98.5 R4 Sand 385 6 98 0.92 98.2 0960-8524/$ -see front matter Ó
Current Research Topics in Applied Microbiology and Microbial Biotechnology, 2009
Microbial characterization of Linear Alkylbenzene Sulfonate degradation in fixed bed anaerobic re... more Microbial characterization of Linear Alkylbenzene Sulfonate degradation in fixed bed anaerobic reactor Lorena Lima de Oliveira*, 1, Iolanda Cristina Silveira Duarte1, and Maria Bernadete A. Varesche1 1 Department of Hydraulics and Sanitation, School of Engineering of São ...
Engenharia Sanitaria e Ambiental, 2010
Journal of the Brazilian Chemical Society, 2006
Este trabalho descreve o desenvolvimento e a validação de um método que usa cromatografia líquida... more Este trabalho descreve o desenvolvimento e a validação de um método que usa cromatografia líquida de alta eficiência para determinação de Alquilbenzeno Linear Sulfonado (LAS) em amostras de águas provenientes de reatores anaeróbios. O padrão de LAS aplicado foi ácido dodecilbenzeno sulfônico-sal sódico, que apresentou 4 picos principais no cromatograma, relacionados aos diferentes homólogos da cadeia alquílica linear. Diferentes condições cromatográficas foram testadas, tais como, fases estacionárias C-18, C-12 e C-8; detectores de ultravioleta e de fluorescência, composição da fase móvel e tempo de programação do gradiente de eluição. A melhor condição cromatográfica obtida foi com a coluna C-8, fase móvel: metanol/ perclorato de sódio 0,075 mol L -1 e detector de fluorescência. A validação deste método foi feita através das curvas de calibração de LAS, usando água e substrato sintético como solventes. O método foi validado com o objetivo de demonstrar sua precisão, linearidade, limite de detecção para cada homólogo e a sua precisão instrumental.
Journal of Environmental Management, 2009
Two horizontal-flow anaerobic immobilized biomass reactors (HAIB) were used to study the degradat... more Two horizontal-flow anaerobic immobilized biomass reactors (HAIB) were used to study the degradation of the LAS surfactant: one filled with charcoal (HAIB1) and the other with a mixed bed of expanded clay and polyurethane foam (HAIB2). The reactors were fed with synthetic substrate supplemented with 14 mg l À1 of LAS, kept at 30 AE 2 C and operated with a hydraulic retention time (HRT) of 12 h. The surfactant was quantified by HPLC. Spatial variation analyses were done to quantify organic matter and LAS consumption along the reactor length. The presence of the surfactant in the load did not affect the removal of organic matter (COD), which was close to 90% in both reactors for an influent COD of 550 mg l À1 . The results of a mass balance indicated that 28% of all LAS added to HAIB1 was removed by degradation. HAIB2 presented 27% degradation. Molecular biology techniques revealed microorganisms belonging the uncultured Holophaga sp., uncultured delta Proteobacterium, uncultured Verrucomicrobium sp., Bacteroides sp. and uncultured gamma Proteobacterium sp. The reactor with biomass immobilized on charcoal presented lower adsorption and a higher kinetic degradation coefficient. So, it was the most suitable support for LAS anaerobic treatment.
Journal of Environmental Management, 2013
Linear alkylbenzene sulfonate (LAS) is an anionic surfactant used in cleaning products, which is ... more Linear alkylbenzene sulfonate (LAS) is an anionic surfactant used in cleaning products, which is usually found in wastewaters. Despite the greater LAS removal rate related to a lower concentrations of volatile fatty acids (VFA), the influence of different ranges of VFA on LAS degradation is not known. LAS degradation was evaluated in upflow anaerobic sludge blanket (UASB) and expanded granular sludge bed (EGSB) reactors at different ranges of VFA concentrations. The reactors were fed with a synthetic wastewater containing LAS (14 mg/L). A greater LAS removal rate (40e80%) was related to the lower and narrower range of acetic acid concentration (1e22 mg/L) in the EGSB reactor. In the UASB reactor, the acetic acid concentrations presented a wider range (2e45 mg/L), and some low LAS removal rates (around 20e25%) were observed even at low acetic acid concentrations (<10 mg/L). The high recirculation rate in the EGSB reactor improved substrate-biomass contact, which resulted in a narrower range of VFA and greater LAS removal rate.
International Journal of Hydrogen Energy, 2008
Clostridium sp a b s t r a c t Heat pre-treatment of the inoculum associated to the pH control wa... more Clostridium sp a b s t r a c t Heat pre-treatment of the inoculum associated to the pH control was applied to select hydrogen-producing bacteria and endospores-forming bacteria. The source of inoculum to the heat pre-treatment was from a UASB reactor used in the slaughterhouse waste treatment. The molecular biology analyses indicated that the microbial consortium presented microorganisms affiliated with Enterobacter cloacae (97% and 98%), Clostridium sp. and Clostridium acetobutyricum (96%), recognized as H 2 and volatile acids' producers. The following assays were carried out in batch reactors in order to verify the efficiencies of sucrose conversion to H 2 by the microbial consortium: 630.0 mg sucrose/L, (2) 1184.0 mg sucrose/L, (3) 1816.0 mg sucrose/L and (4) 4128.0 mg sucrose/L. The subsequent yields were obtained as follows: 15% (1.2 mol H 2 /mol sucrose), 20% (1.6 mol H 2 /mol sucrose), 15% (1.2 mol H 2 /mol sucrose) and 4% (0.3 mol H 2 /mol sucrose), respectively. The intermediary products were acetic acid, butyric acid, methanol and ethanol in all of the anaerobic reactors. ª (S.I. Maintinguer), varesche@sc.usp.br (M.B. Varesche). A v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / h e
International Journal of Hydrogen Energy, 2011
International Biodeterioration & Biodegradation, 2010
This study aimed to determine the efficiency of an anaerobic stirred sequencing-batch reactor con... more This study aimed to determine the efficiency of an anaerobic stirred sequencing-batch reactor containing granular biomass for the degradation of linear alkylbenzene sulfonate (LAS), a surfactant present in household detergent. The bioreactor was monitored for LAS concentrations in the influent, effluent and sludge, pH, chemical oxygen demand, bicarbonate alkalinity, total solids, and volatile solids. The degradation of LAS was found
Environmental Technology, 2013
The effect of a lipase-rich enzyme preparation produced by the fungus Penicillium sp. on solid-st... more The effect of a lipase-rich enzyme preparation produced by the fungus Penicillium sp. on solid-state fermentation was evaluated in two anaerobic bioreactors (up-flow anaerobic sludge blanket (UASB) and horizontal-flow anaerobic immobilized biomass (HAIB)) treating dairy wastewater with 1200 mg oil and grease/L. The oil and grease hydrolysis step was carried out with 0.1% (w/v) of the solid enzymatic preparation at 30 degrees C for 24 h. This resulted in a final concentration of free acids eight times higher than the initial value. The bioreactors operated at 30 degrees C with hydraulic retention times of 12 h (HAIB) and 20 h (UASB) for a period of 430 days, and had high chemical oxygen demand (COD) removal efficiencies (around 90%) when fed with pre-hydrolyzed wastewater. There was, however, an increase in the effluent oil and grease concentration (from values as low as 17 mg/L to values above 150 mg/L in the UASB bioreactor, and from 38-242 mg/L in the HAIB bioreactor), and oil and grease accumulation in the biomass throughout the operational period (the oil and grease content reached 1.7 times that found in the inoculum of the UASB bioreactor). The HAIB bioreactor gave better results because the support for biomass immobilization acted as a filter, retaining oil and grease at the entry of the bioreactor. The molecular analysis of the Bacteria and Archaea domains revealed significant differences in the microbial profiles in experiments conducted with and without the pre-hydrolysis step. The differences observed in the overall parameters could be related to the microbial diversity of the anaerobic sludge.
Brazilian Journal of Chemical Engineering, 2013
Brazilian Archives of Biology and Technology, 2011
In this work, the biological denitrification associated with anoxic oxidation of methane and the ... more In this work, the biological denitrification associated with anoxic oxidation of methane and the microbial diversity involved were studied. Kinetic tests for nitrate and nitrite (NO 2 -) removal and methane uptake were carried out in 100 mL batch reactors incubated in a shaker (40 rpm) at 30 o C. Denitrificant/methanotrophic biomass was taken from a laboratory scale reactor fed with synthetic nitrified substrates (40 mgN L -1 of NO 3 and subsequently NO 2 -) and methane as carbon source. Results obtained from nitrate removal followed a first order reaction, presenting a kinetic apparent constant (k NO3) ) of 0.0577±0.0057d -1 . Two notable points of the denitrification rate (0.12gNO 3 --N g -1 AVS d -1 and 0.07gNO 3 --N g -1 AVS d -1 ) were observed in the beginning and on the seventh day of operation. When nitrite was added as an electron acceptor, denitrification rates were improved, presenting an apparent kinetic constant (k NO2 ) of 0.0722±0.0044d -1 , a maximum denitrification rate of 0.6gNO 2 --N g -1 AVS d -1 , and minimum denitrification rate of 0.1gNO 2 --N g -1 AVS d -1 at the beginning and end of the test, respectively. Endogenous material supporting denitrification and methane concentration dissolved in the substrate was discarded from the control experiments in the absence of methane and seed, respectively. Methylomonas sp. was identified in the reactors fed with nitrate and nitrite as well as uncultured bacterium.
Bioresource Technology, 2013
Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the ... more Degradation of linear alkylbenzene sulfonate (LAS) in UASB reactors was optimized by varying the bioavailability of LAS based on the concentration of biomass in the system (1.3-16 g TS/L), the hydraulic retention time (HRT), which was operated at 6, 35 or 80 h, and the concentration of co-substrates as specific organic loading rates (SOLR) ranging from 0.03-0.18 g COD/g TVS.d. The highest degradation rate of LAS (76%) was related to the lowest SOLR (0.03 g COD/g TVS.d). Variation of the HRT between 6 and 80 h resulted in degradation rates of LAS ranging from 18% to 55%. Variation in the bioavailability of LAS resulted in discrete changes in the degradation rates (ranging from 37-53%). According to the DGGE profiles, the archaeal communities exhibited greater changes than the bacterial communities, especially in biomass samples that were obtained from the phase separator. The parameters that exhibited more influence on LAS degradation were the SOLR followed by the HRT.
Bioresource Technology, 2010
Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorb... more Table 4 LAS mass balance. Reactor Support material Influent (mg) Effluent (mg) Removal (%) Adsorbed (mg) Degradation (%) R1 Activated carbon 331 12 96 34 86 R2 Expanded clay 306 51 83 0 83 R3 Glass beads 385 5 99 0.81 98.5 R4 Sand 385 6 98 0.92 98.2 0960-8524/$ -see front matter Ó
Bioresource Technology, 2009
The effect of a lipase-rich fungal enzymatic preparation, produced by a Penicillium sp. during so... more The effect of a lipase-rich fungal enzymatic preparation, produced by a Penicillium sp. during solid-state fermentation, was evaluated in an anaerobic digester treating dairy wastewater with 1200 mg of oil and grease/L. The oil and grease hydrolysis step was carried out with 0.1% (w/v) of solid enzymatic preparation at 30°C for 24 h, and resulted in a final free acid concentration eight times higher than the initial value. The digester operated in sequential batches of 48 h at 30°C for 245 days, and had high chemical oxygen demand (COD) removal efficiencies (around 90%) when fed with pre-hydrolyzed wastewater. However, when the pre-hydrolysis step was removed, the anaerobic digester performed poorly (with an average COD removal of 32%), as the oil and grease accumulated in the biomass and effluent oil and grease concentration increased throughout the operational period. PCR-DGGE analysis of the Bacteria and Archaea domains revealed remarkable differences in the microbial profiles in trials conducted with and without the pre-hydrolysis step, indicating that differences observed in overall parameters were intrinsically related to the microbial diversity of the anaerobic sludge.
Bioresource Technology, 2010
Linear alkylbenzene sulfonate (LAS) is an anionic surfactant widely used to manufacture detergent... more Linear alkylbenzene sulfonate (LAS) is an anionic surfactant widely used to manufacture detergents and found in domestic and industrial wastewater. LAS removal was evaluated in a horizontal anaerobic immobilized biomass reactor. The system was filled with polyurethane foam and inoculated with sludge that was withdrawn from an up flow anaerobic sludge blanket reactor that is used to treat swine wastewater. The reactor was fed with easily degradable substrates and a solution of commercial LAS for 313 days. The hydraulic retention time applied was 12 h. The system was initially operated without detergent and resulted to 94% reduction of demand. The mass balance in the system indicated that the LAS removal efficiency was 45% after 180 days. From the 109th day to the 254th day, a removal efficiency of 32% was observed. The removal of LAS was approximately 40% when 1500 mg of LAS were applied in the absence of co-substrates suggesting that the LAS molecules were used selectively. Microscopic analyses of the biofilm revealed diverse microbial morphologies and denaturing gradient gel electrophoresis profiling showed variations in the total bacteria and sulfate-reducing bacteria populations. 16S rRNA sequencing and phylogenetic analyses demonstrated that members of the order Clostridiales were the major components of the bacterial community in the last step of the reactor operation.
Biodegradation, 2008
The purpose of this work was to assess the degradation of linear alkylbenzene sulfonate (LAS) in ... more The purpose of this work was to assess the degradation of linear alkylbenzene sulfonate (LAS) in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor. The reactor was filled with polyurethane foam where the sludge from a sanitary sewage treatment was immobilized. The hydraulic detention time (HDT) used in the experiments was of 12 h. The reactor was fed with synthetic substrate (410 mg l(-1) of meat extract, 115 mg l(-1) of starch, 80 mg l(-1) of saccharose, 320 mg l(-1) of sodium bicarbonate and 5 ml l(-1) of salt solution) in the following stages of operation: SI-synthetic substrate, SII-synthetic substrate with 7 mg l(-1) of LAS, SIII-synthetic substrate with 14 mg l(-1) of LAS and SIV-synthetic substrate containing yeast extract (substituting meat extract) and 14 mg l(-1) of LAS, without starch. At the end of the experiment (313 days) a degradation of approximately 35% of LAS was achieved. The higher the concentration of LAS, the greater the amount of foam for its adsorption. This is necessary because the isotherm of LAS adsorption in the foam is linear for the studied concentrations (2 to 50 mg l(-1)). Microscopic analyses of the biofilm revealed diverse microbial morphologies, while Denaturing Gradient Gel Eletrophoresis (DGGE) profiling showed variations in the population of total bacteria and sulphate-reducing bacteria (SRB). The 16S rRNA gene sequencing and phylogenetic analyses revealed that the members of the order Clostridiales were the major components of the bacterial community in the last reactor operation step.
Page 257. Evaluation of the microbial diversity in anaerobic reactors fed with sucrose applied to... more Page 257. Evaluation of the microbial diversity in anaerobic reactors fed with sucrose applied to hydrogen production Sandra I. Maintinguer*, Bruna S. Fernandes, Iolanda Duarte, Kátia Saavedra, M. Bernadete A. Varesche Department ...
… Sanitaria e Ambiental, 2010
... a utilização de fungos, embora boa parte dos trabalhos encontrados seja com uso de biomassa m... more ... a utilização de fungos, embora boa parte dos trabalhos encontrados seja com uso de biomassa morta (FU; VIRARAGHAVAN, 2002; KUMARE; ABRAHAM, 2007 ... suporte foi removido com ajuda de pérolas de vidro e água destilada esterilizada a 121ºC a 1 atm, procedendo-se ...