RESUMEN

Despite the importance of anaerobic sludge extracellular polymeric substances (EPSs), their characterization is limited to information regarding their chemical classes and molecular size. This work explores the possibility of using proteomic techniques to study the proteins present in this matrix. Thus, this paper compares eight EPS extraction methods regarding extraction yield, protein/carbohydrate ratio, size distribution profile and suitability to sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses. Despite the differences found in quantification and size exclusion chromatography assays, the band profile found for all methods was very similar. Considering the band pattern, extraction time and background level, heating method followed by ammonium sulfate precipitation proved to be the most appropriate method for gel-based analyses of anaerobic sludge EPS proteins.

Asunto(s)

Carbohidratos/análisis , Polímeros/análisis , Proteínas/análisis , Proteómica/métodos , Anaerobiosis , Cromatografía Liquida , Electroforesis en Gel de Poliacrilamida , Peso Molecular , Aguas del Alcantarillado/análisis , Espectrometría de Masas en Tándem

RESUMEN

The present work aimed to investigate the microbial dynamics during the anaerobic treatment of the azo dye blue HRFL in bench scale upflow anaerobic sludge bed (UASB) reactor operated at ambient temperature. Sludge samples were collected under distinct operational phases, when the reactor were stable (low variation of color removal), to assess the effect of glucose and yeast extract as source of carbon and redox mediators, respectively. Reactors performance was evaluated based on COD (chemical oxygen demand) and color removal. The microbial dynamics were investigated by PCR-DGGE (Polimerase Chain Reaction - Denaturing Gradient of Gel Electrophoresis) technique by comparing the 16S rDNA profiles among samples. The results suggest that the composition of microorganisms changed from the beginning to the end of the reactor operation, probably in response to the presence of azo dye and/or its degradation byproducts. Despite the highest efficiency of color removal was observed in the presence of 500 mg/L of yeast extract (up to 93%), there were no differences regarding the microbial profiles that could indicate a microbial selection by the yeast extract addition. On the other hand Methosarcina barkeri was detected only in the end of operation when the best efficiencies on color removal occurred. Nevertheless the biomass selection observed in the last stages of UASB operation is probably a result of the washout of the sludge in response of accumulation of aromatic amines which led to tolerant and very active biomass that contributed to high efficiencies on color removal.

Asunto(s)

Compuestos Azo/metabolismo , Biota , Análisis de la Demanda Biológica de Oxígeno , Biotransformación , Reactores Biológicos/microbiología , Análisis por Conglomerados , Color , Electroforesis en Gel de Gradiente Desnaturalizante , ADN Ribosómico/química , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa

RESUMEN

The present work aimed to investigate the microbial dynamics during the anaerobic treatment of the azo dye blue HRFL in bench scale upflow anaerobic sludge bed (UASB) reactor operated at ambient temperature. Sludge samples were collected under distinct operational phases, when the reactor were stable (low variation of color removal), to assess the effect of glucose and yeast extract as source of carbon and redox mediators, respectively. Reactors performance was evaluated based on COD (chemical oxygen demand) and color removal. The microbial dynamics were investigated by PCR-DGGE (Polimerase Chain Reaction - Denaturing Gradient of Gel Electrophoresis) technique by comparing the 16S rDNA profiles among samples. The results suggest that the composition of microorganisms changed from the beginning to the end of the reactor operation, probably in response to the presence of azo dye and/or its degradation byproducts. Despite the highest efficiency of color removal was observed in the presence of 500 mg/L of yeast extract (up to 93%), there were no differences regarding the microbial profiles that could indicate a microbial selection by the yeast extract addition. On the other hand Methosarcina barkeri was detected only in the end of operation when the best efficiencies on color removal occurred. Nevertheless the biomass selection observed in the last stages of UASB operation is probably a result of the washout of the sludge in response of accumulation of aromatic amines which led to tolerant and very active biomass that contributed to high efficiencies on color removal.

Asunto(s)

Compuestos Azo/metabolismo , Biota , Análisis de la Demanda Biológica de Oxígeno , Biotransformación , Reactores Biológicos/microbiología , Análisis por Conglomerados , Color , Electroforesis en Gel de Gradiente Desnaturalizante , ADN Ribosómico/química , ADN Ribosómico/genética , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , /genética , Análisis de Secuencia de ADN , Aguas del Alcantarillado/microbiología

RESUMEN

The present work aimed to investigate the microbial dynamics during the anaerobic treatment of the azo dye blue HRFL in bench scale upflow anaerobic sludge bed (UASB) reactor operated at ambient temperature. Sludge samples were collected under distinct operational phases, when the reactor were stable (low variation of color removal), to assess the effect of glucose and yeast extract as source of carbon and redox mediators, respectively. Reactors performance was evaluated based on COD (chemical oxygen demand) and color removal. The microbial dynamics were investigated by PCR-DGGE (Polimerase Chain Reaction - Denaturing Gradient of Gel Electrophoresis) technique by comparing the 16S rDNA profiles among samples. The results suggest that the composition of microorganisms changed from the beginning to the end of the reactor operation, probably in response to the presence of azo dye and/or its degradation byproducts. Despite the highest efficiency of color removal was observed in the presence of 500 mg/L of yeast extract (up to 93%), there were no differences regarding the microbial profiles that could indicate a microbial selection by the yeast extract addition. On the other hand Methosarcina barkeri was detected only in the end of operation when the best efficiencies on color removal occurred. Nevertheless the biomass selection observed in the last stages of UASB operation is probably a result of the washout of the sludge in response of accumulation of aromatic amines which led to tolerant and very active biomass that contributed to high efficiencies on color removal.

Asunto(s)

Compuestos Azo/metabolismo , Biota , Análisis de la Demanda Biológica de Oxígeno , Reactores Biológicos/microbiología , Biotransformación , Análisis por Conglomerados , Color , ADN Ribosómico/química , ADN Ribosómico/genética , Electroforesis en Gel de Gradiente Desnaturalizante , Datos de Secuencia Molecular , Filogenia , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Aguas del Alcantarillado/microbiología

RESUMEN

This work investigated the anaerobic degradation of the model azo dye Remazol Yellow Gold RNL in an upflow anaerobic sludge blanket reactor (UASB) and two submerged anaerobic membrane (SAMBR) bioreactors, one of which (SAMBR-1) was operated with powdered activated carbon (PAC) in its interior. The reactors were operated at 35 °C with a hydraulic retention time of 24 h in three operational phases, aimed to assess the effect of external sources of carbon (glucose) or redox mediator (yeast extract) on the removal or color and organic matter. The results showed that removal efficiencies of COD (73-94%) and color (90-94%) were higher for SAMBR-1 when compared to SAMBR-2 (operated without PAC) and UASB reactors. In addition, the presence of PAC in SAMBR-1 increased reactor stability, thereby leading to a lower accumulation of volatile fatty acids (VFA). The microfiltration membrane was responsible for an additional removal of ~50% of soluble residual COD in the form of VFA, thus improving permeate quality. On its turn, PAC exhibited the ability to adsorb byproducts (aromatic amines) of azo dye degradation as well as to act as source of immobilized redox mediator (quinone groups on its surface), thereby enhancing color removal.

Asunto(s)

Compuestos Azo/metabolismo , Reactores Biológicos , Colorantes/metabolismo , Ácidos Sulfanílicos/metabolismo , Eliminación de Residuos Líquidos/instrumentación , Aminas/metabolismo , Anaerobiosis , Análisis de la Demanda Biológica de Oxígeno , Reactores Biológicos/microbiología , Carbono/metabolismo , Carbón Orgánico , Color , Diseño de Equipo , Ácidos Grasos Volátiles/metabolismo , Filtración/instrumentación , Riboflavina/metabolismo , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/metabolismo

RESUMEN

This work investigated the occurrence of pharmaceuticals and endocrine disrupting compounds (EDCs) in raw sewage (from Belo Horizonte city, Minas Gerais state, Brazil) and assessed their behavior in demo-scale upflow anaerobic sludge blanket reactors (UASB reactors) operated at different hydraulic retention times (HRT). The dissolved concentration of the studied micropollutants in the raw and treated sewage was obtained using solid phase extraction (SPE) followed by analysis in a liquid chromatography system coupled to a hybrid high resolution mass spectrometer consisting of an ion-trap and time of flight (LC-MS-IT-TOF). The natural (estradiol) and synthetic (ethinylestradiol) estrogens were hardly detected; when present, however, their concentrations were lower than the method quantification limits. The concentrations of bisphenol A and miconazole in raw sewage were similar to that reported in the literature (around 200 ng L⁻¹ and hardly detected, respectively). The antibiotics sulfamethoxazole (median 13.0 ng L⁻¹) and trimethoprim (median 61.5 ng L⁻¹), and the other pharmaceutical compounds (diclofenac and bezafibrate, with median 99.9 and 94.4 ng L⁻¹, respectively) were found in lower concentrations when compared with reports in the literature, which might indicate a lower consumption of such drugs in Brazil. The UASB reactors were inefficient in the removal of bisphenol A, and led to an increased concentration of nonylphenol in the effluent. The anaerobic reactors were also inefficient in the removal of diclofenac, and led to a partial removal of bezafibrate; whereas, for sulfamethoxazole there seemed to be a direct relationship between the HRT and removal efficiencies. For trimethoprim the sludge retention time (SRT) seemed to play an important role, although it was only partially removed in the UASB reactors.

Asunto(s)

Reactores Biológicos , Disruptores Endocrinos/análisis , Preparaciones Farmacéuticas/análisis , Reología , Aguas del Alcantarillado/química , Contaminantes Químicos del Agua/análisis , Anaerobiosis , Biodegradación Ambiental , Brasil , Cromatografía Liquida , Lluvia , Reproducibilidad de los Resultados , Factores de Tiempo , Eliminación de Residuos Líquidos

RESUMEN

This work investigated the use of submerged anaerobic membrane bioreactors (SAMBRs) in the presence and absence of powdered activated carbon (PAC) for the treatment of genuine textile wastewater. The reactors were operated at 35 °C with an HRT of 24 h and the textile effluent was diluted (1:10) with nutrient solution containing yeast extract as the source of the redox mediation riboflavin. The results showed that although both SAMBRs exhibited an excellent performance, the presence of PAC inside SAMBR-1 enhanced reactor stability and removal efficiency of chemical oxygen demand (COD), volatile fatty acids (VFA), turbidity and color. The median removal efficiencies of COD and color in SAMBR-1 were, 90 and 94% respectively; whereas for SAMBR-2 (without PAC) these values were 79 and 86%, In addition, the median values of turbidity and VFA were 8 NTU and 8 mg/L for SAMBR-1 and 14 NTU and 26 mg/L for SAMBR-2, indicating that the presence of PAC inside SAMBR-1 led to the production of an anaerobic effluent of high quality regarding such parameters.

Asunto(s)

Reactores Biológicos , Carbono/química , Polvos , Industria Textil , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/metabolismo , Anaerobiosis , Contaminantes Químicos del Agua/química , Purificación del Agua

RESUMEN

This paper presents results on anaerobic degradation of the azo dye blue HFRL in a bench scale Upflow anaerobic sludge blanket (UASB) reactor operated at ambient temperature. The results show that the addition of yeast extract (500 mg/L) increased color removal (P < 0.05) from 62 to 93% despite the low chemical oxygen demand (COD) removal (~35%) which happened due to volatile fatty acids (VFA) accumulation. There were no differences in color removal (~91%) when yeast extract (500 mg/L) was used in the presence or absence of glucose, suggesting that yeast extract acted as source of redox mediator (riboflavin) and carbon. The specific rate of dye removal increased along the operational phases and depended on the presence of yeast extract, suggesting progressive biomass acclimatization. Analysis of bacterial diversity by Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) method showed there was biomass selection along the bioreactor operation and no evidence of azo dye degrading bacteria predominance. This strengthens the hypothesis that color removal happens extracellularly by the reduction of azo bond by reduced redox mediators, such as riboflavin, which is present in high amount in the yeast extract.

Asunto(s)

Antraquinonas/metabolismo , Compuestos Azo/metabolismo , Reactores Biológicos/microbiología , Carbono/farmacología , Colorantes/metabolismo , Aguas del Alcantarillado/microbiología , Compuestos de Vinilo/metabolismo , Levaduras/metabolismo , Anaerobiosis/efectos de los fármacos , Bacterias/efectos de los fármacos , Bacterias/genética , Secuencia de Bases , Biodegradación Ambiental/efectos de los fármacos , Análisis de la Demanda Biológica de Oxígeno , Color , ADN Ribosómico/genética , Electroforesis en Gel de Gradiente Desnaturalizante , Ácidos Grasos Volátiles/análisis , Concentración de Iones de Hidrógeno/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Reología/efectos de los fármacos , Solubilidad/efectos de los fármacos , Temperatura , Eliminación de Residuos Líquidos

RESUMEN

This paper aimed at measuring the concentration of methane dissolved in effluents from different UASB reactors (pilot-, demo- and full-scale) treating domestic wastewater, in order to calculate the degree of saturation of such greenhouse gas and evaluate the losses of energetic potential in such systems. The results showed that methane saturation degrees, calculated according to Henry's law, varied from ∼1.4 to 1.7 in the different reactors, indicating that methane was oversaturated in the liquid phase. The overall results indicated that the losses of dissolved methane in the anaerobic effluents were considerably high, varying from 36 to 41% of total methane generated in the reactor. These results show that there is considerable uncontrolled loss of methane in anaerobic wastewater treatment plants, implying the need of research on technologies aimed at recovering such energetic greenhouse gas.

Asunto(s)

Reactores Biológicos , Metano/química , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/química , Anaerobiosis , Biocombustibles

RESUMEN

A conceptual and integrated analysis of the UASB/Polishing Pond system is presented in relation to the removal of specific constituents not normally covered in the pond's literature, namely surfactants (linear alkylbenzene sulphonate, LAS), micropollutants (phthalates and bisphenol A) and sulfide. Experimental studies carried out on a small full-scale UASB/PP system have shown limited overall removal efficiencies for some constituents (53% to 70% for phthalates and 50% for LAS), but excellent removal levels for bisphenol A (around 99%) and sulfide (no trace concentrations were detected in the second and third ponds of the series). Further research is needed to investigate possible limitations and to identify means to improve the performance of the UASB/PP system.

Asunto(s)

Reactores Biológicos , Gases , Tensoactivos/aislamiento & purificación , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/métodos , Ácidos Alcanesulfónicos/aislamiento & purificación , Anaerobiosis , Compuestos de Bencidrilo , Biodegradación Ambiental , Diseño de Equipo , Agua Dulce , Sulfuro de Hidrógeno/química , Fenoles/aislamiento & purificación , Ácidos Ftálicos/química , Sulfuros/química , Sulfuros/aislamiento & purificación , Tensoactivos/química , Eliminación de Residuos Líquidos/instrumentación

RESUMEN

The measurement of sludge bioavailability and biodegradability is important to assess the sludge potential as a source of carbon and energy during its biological stabilization. As the majority of biological sludge (secondary sludge) consists of biomass, an increase in sludge bioavailability can be achieved by using different techniques for cell lysis, which is aimed at releasing intracellular organics into the bulk solution and enhancing hydrolysis of particulate organic matter. This paper reviews the main methodologies currently used for cell lysis, which include thermal, ultrasonic and chemical techniques and a combination of these, as well as the analytical procedures that can be employed to assess the degree of lysis and sludge solubilization. In addition, this paper also discusses common techniques that can be used for measuring the biodegradability of sludge under aerobic and anaerobic conditions.

Asunto(s)

Biodegradación Ambiental , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Solubilidad

RESUMEN

ABSTRACT A serologic survey was conducted among 131 swine slaughtered in the public slaughterhouse of Patos city, Northeast region of Brazil, to determine the prevalence of anti-Leptospira spp. agglutinins. For serologic diagnosis of leptospirosis, the microscopic agglutination test (MAT) was carried out using live cultures of 22 pathogenic and two saprophytic Leptospira spp. serovars. The most frequent serovar was found crossing the results of frequency and titer of agglutinins, and sera presenting equal titers for two or more serovars were not considered for this analysis. Of the 131 swine analyzed, 44 were seropositive for at least one Leptospira spp. serovar, resulting in a seroprevalence of 33.6% (95% CI = 25.5% 42.4%). The most frequent serovar was Pomona, with 38 (29.0%; 95% CI = 21.4% 37.6%) reactant sera. Other reactant serovars and respective prevalence were: Pyrogenes (2.3%; 95% CI = 0.5% 6.5%), Canicola (1.5%; 95% CI = 0.2% 5.4%) and Shermani (0.8%; 95% CI = 0.02% 4.2%). There was statistical difference in seroprevalence to serovar Pomona compared with others reactant serovars (P 0.0001).

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RESUMO Com o objetivo de determinar a prevalência de aglutininas anti-Leptospira spp., foi realizado um inquérito sorológico em 131 suínos abatidos no matadouro público de Patos, Estado da Paraíba, Brasil. Para o diagnóstico sorológico de leptospirose, foi utilizada a técnica de soroaglutinação microscópica (SAM), utilizando-se culturas vivas de 22 sorovares patogênicos e dois sorovares saprófitos de Leptospira spp. Para a determinação do sorovar mais provável, foram considerados o título de aglutininas e a freqüência de soros reagentes. Soros que apresentaram títulos iguais para dois ou mais sorovares foram excluídos desta análise. Dos 131 suínos, 44 foram soropositivos para pelo menos um dos sorovares empregados, resultando em uma soroprevalência de 33,6% (IC 95% = 25,5% 42,4%). O sorovar mais provável foi o Pomona, com 38 (29,0%; IC 95% = 21,4% 37,6%) soros reagentes. Também foram constatadas reações sorológicas para os seguintes sorovares: Pyrogenes (2,3%; IC 95% = 0,5% 6,5%), Canicola (1,5%; IC 95% = 0,2% 5,4%) e Shermani (0,8%; IC 95% = 0,02% 4,2%). Houve diferença significativa na soroprevalência para o sorovar Pomona em relação aos demais sorovares (P 0,0001).

RESUMEN

There are few studies in the literature that have aimed at characterizing the physical, chemical, and microbial aspects of scum produced in UASB reactors. In addition, there is little information on the influence of operational conditions of UASB reactors on scum formation, and the present work addresses these issues. Three demo-scale UASB reactors, fed on domestic wastewater, were employed to monitor the formation and its characteristics. Scum production was periodically assessed during different operational phases, and its characterization involved analyses of BOD, COD, solids, sulfide, sulfate, microscopic observations, as well as biodegradability tests. The results show that the scum formed was physically, chemically, and microscopically similar in both geminated reactors, being comprised mainly of organic material of low biodegradability. Several bacterial morphotypes, mainly filaments and rods, with internal sulfur granules, were observed, and the aerobic microorganisms that developed at the scum layer as a result of photosynthetic activity of cyanobacteria, seemed to play an important role in sulfide removal and odour control. Scum production rates were similar in both reactors, but the imposed higher upflow velocities resulted in a higher production rate and in a reduced biodegradability of the scum.

Asunto(s)

Reactores Biológicos , Cianobacterias/metabolismo , Odorantes/prevención & control , Aguas del Alcantarillado , Eliminación de Residuos Líquidos/métodos , Biodegradación Ambiental , Cianobacterias/crecimiento & desarrollo , Vivienda , Microscopía , Compuestos Orgánicos/metabolismo , Oxígeno/metabolismo , Fotosíntesis , Aguas del Alcantarillado/microbiología , Sulfatos/metabolismo , Sulfuros/metabolismo

RESUMEN

This paper presents results on the quantification and chromatographic characterization of soluble microbial products (SMP) accumulated in two laboratory-scale reactors: a submerged anaerobic membrane reactor (SAMBR or MBR), and an anaerobic CSTR. The results obtained under steady-state conditions show that 2.1% of the substrate was channelled into the production of SMP in the CSTR, whilst in the SAMBR this was estimated to be 25%. Chromatographic characterization showed that more hydrophobic and high MW organics that absorb at 254 nm were detected in the SAMBR supernatant than in the CSTR. A comparison of chromatograms suggest that the release of extracellular polymers (ECP) and cell lysis may be important sources of SMP in the SAMBR. Electrophoresis results confirmed that there was more soluble protein inside the SAMBR, and showed that the release of ECP by shear or hydrolysis seemed to have contributed to the production of protein-like SMP in both systems.

Asunto(s)

Restauración y Remediación Ambiental/instrumentación , Compuestos Orgánicos/química , Anaerobiosis , Cromatografía Líquida de Alta Presión , Electroforesis en Gel de Poliacrilamida , Solubilidad , Espectrofotometría Ultravioleta