Tratamento de águas residuárias de suinocultura em reatores anaeróbios horizontais de alta taxa seguidos de filtro biológico percolador

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Process optimization of an aerobic upflow sludge blanket reactor system

Response of an aerobic upflow sludge blanket (AUSB) reactor system to the changes in operating conditions was investigated by varying two principle operating variables: the oxygenation pressure and the flow recirculation rate. The oxygenation pressure was varied between 0 and 25 psig (relative), while flow recirculation rates were between 1,300 and 600% correspondingly. The AUSB reactor system was able to handle a volumetric loading of as high as 3.8 kg total organic carbon (TOC)/m(3) day, with a removal efficiency of 92%. The rate of TOC removal by AUSB was highest at a pressure of 20 psig and it decreased when the pressure was increased to 25 psig and the flow recirculation rate was reduced to 600%. The TOC removal rate also decreased when the operating pressure was reduced to 0 and 15 psig, with corresponding increase in flow recirculation rates to 1,300 and 1,000%, respectively. Maintenance of a high dissolved oxygen level and a high flow recirculation rate was found to improve the substrate removal capacity of the AUSB system. The AUSB system was extremely effective in retaining the produced biomass despite a high upflow velocity and the overall sludge yield was only 0.24-0.32 g VSS/g TOC removed. However, the effluent TOC was relatively high due to the system's operation at a high organic loading.

Performance evaluation and phylogenetic characterization of anaerobic fluidized bed reactors using ground tire and pet as support materials for biohydrogen production

This study evaluated two different support materials (ground tire and polyethylene terephthalate [PET]) for biohydrogen production in an anaerobic fluidized bed reactor (AFBR) treating synthetic wastewater containing glucose (4000 mg L(-1)). The AFBR, which contained either ground tire (R1) or PET (R2) as support materials, were inoculated with thermally pretreated anaerobic sludge and operated at a temperature of 30 degrees C. The AFBR were operated with a range of hydraulic retention times (HRT) between 1 and 8 h. The reactor R1 operating with a HRT of 2 h showed better performance than reactor R2, reaching a maximum hydrogen yield of 2.25 mol H(2) mol(-1) glucose with 1.3 mg of biomass (as the total volatile solids) attached to each gram of ground tire. Subsequent 16S rRNA gene sequencing and phylogenetic analysis of particle samples revealed that reactor R1 favored the presence of hydrogen-producing bacteria such as Clostridium, Bacillus, and Enterobacter. (C) 2010 Elsevier Ltd. All rights reserved.

Dynamics of sulfidogenesis associated to methanogenesis in horizontal-flow anaerobic immobilized biomass reactor

Two bench-scale horizontal anaerobic fixed bed reactors were tested to remove both sulfate and organic matter from wastewater. First, the reactors (R1 and R2) were supplied with synthetic wastewater containing sulfate and a solution of ethanol and volatile fatty acids. Subsequently, RI and R2 were fed with only ethanol or acetate, respectively. The substitution to ethanol in R1 increased the sulfate reduction efficiency from 83% to nearly 100% for a chemical oxygen demand to sulfate (COD/sulfate) ratio of 3.0. In contrast, in R2, the switch in carbon source to acetate strongly decreased sulfidogenesis and the maximum sulfate reduction achieved was 47%. Process stability in long-term experiments and high removal efficiencies of both organic matter and sulfate were achieved with ethanol as the sole carbon source. The results allow concluding that syntrophism instead of competition between the sulfate reducing bacteria and acetoclastic methanogenic archaeal populations prevailed in the reactor. (C) 2009 Elsevier Ltd. All rights reserved.

Performance of a horizontal-flow anaerobic immobilized biomass (HAIB) reactor and dynamics of the microbial community during degradation of pentachlorophenol (PCP)

The anaerobic biological treatment of pentachlorophenol (PCP) and methanol as the main carbon source was investigated in a horizontal-flow anaerobic immobilized biomass (HAIB) reactor at 30 +/- 1 degrees C, during a 220-day trial period. The reactor biomass was developed as an attached biofilm on polyurethane foam particles, with 24 h of hydraulic retention time. The PCP concentrations, which ranged from 2.0 to 13.0 mg/L, were controlled by adding synthetic substrate. The HAIB reactor reduced 97% of COD and removed 99% of PCP. The microbial biofilm communities of the HAIB reactor amended with PCP, without previous acclimatization, were characterized by polymerase chain reaction (PCR) and amplified ribosomal DNA restriction analysis (ARDRA) with specific Archaea oligonucleotide primers. The ARDRA technique provided an adequate analysis of the community, revealing the profile of the selected population along the reactor. The biomass activities in the HAIB reactor at the end of the experiments indicated the development of PCP degraders and the maintenance of the population of methanogenic Archaea, ensuring the high efficiency of the system treating PCP with added methanol as the cosubstrate. The use of the simplified ARDRA method enabled us to monitor the microbial population with the addition of high concentrations of toxic compounds and highlighting a selection of microorganisms in the biofilm. (C) 2008 Published by Elsevier Ltd.

Evaluation of the microbial diversity in a horizontal-flow anaerobic immobilized biomass reactor treating linear alkylbenzene sulfonate

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 similar to 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.

Biohydrogen production in anaerobic fluidized bed reactors: Effect of support material and hydraulic retention time

This study evaluated two different support materials (polystyrene and expanded clay) for biohydrogen production in an anaerobic fluidized bed reactor (AFBR) treating synthetic wastewater containing glucose (4000 mg L(-1)). The AFBRs contained either polystyrene (R1) or expanded clay (R2) as support materials were inoculated with thermally pre-treated anaerobic sludge and operated at a temperature of 30 degrees C and a pH of approximately 5.5. The AFBRs were operated with a range of hydraulic retention times (HRTs) between 1 and 8 h. For R1 with an HRT of 2 h, the maximum hydrogen yield (HY) was 1.90 mol H(2) mol(-1) glucose, with 0.805 mg of biomass (as total volatile solids, or TVS) attached to each g of polystyrene. For R2 operated at an HRT of 2 h, the maximum HY was 2.59 mol H(2) moll glucose, with 1.100 mg of attached biomass (as TVS) g(-1) expanded clay. The highest hydrogen production rates (HPR) were 0.95 and 1.21 L h(-1) L(-1) for R1 and R2, respectively, using an HRT of 1 h. The H(2) content increased from 16-47% for R1 and from 22-51% for R2. No methane was detected in the biogas produced throughout the period of AFBR operation. These results show that the values of HY, HPR, H(2) content, and g of attached biomass g(-1) support material were all higher for AFBRs containing expanded clay than for reactors containing polystyrene. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

The influence of calcium on granular sludge in a full-scale UASB treating paper mill wastewater

Calcium precipitation can have a number of effects on the performance of high-rate anaerobic performance including cementing of the sludge bed, limiting diffusion, and diluting the active biomass. The aim of this study was to observe the influence of precipitation in a stable full-scale system fed with high-calcium paper factory wastewater. Granules were examined from an upflow anaerobic sludge blanket reactor (volume 1,805 m(3)) at a recycled paper mill with a loading rate of 5.7-6.6 kgCOD.m(-3).d(-1) and influent calcium concentration of 400-700 gCa(.)m(-3). The granules were relatively small (1 mm), with a 200-400 mum core of calcium precipitate as observed with energy dispersive X-ray spectroscopy. Compared to other granules, Methanomicrobiales not Methanobacteriales were the dominant hydrogen or formate utilisers, and putative acidogens were filamentous. The strength of the paper mill fed granules was very high when compared to granules from other full-scale reactors, and a partial linear correlation between granule strength and calcium concentration was identified.

Carbon materials as new generation of new electron shuttles for the anaerobic degradation of environmental xenobiotics

Tese de Doutoramento em Engenharia Química e Biológica

A biochemical predictor of performance during mesophilic anaerobic fermentation of starch wastewater

The aim of this study was to determine the potential of biochemical parameters, such as enzyme activity and adenosine triphosphate (ATP) levels, as monitors of process performance in the Upflow Anaerobic Sludge Blanket (UASB) reactor utilizing a starch wastewater. The acid and alkaline phosphatase activity and the ATP content of the UASB sludge were measured in response to changes in flow rate and nutrient loading. Conventional parameters of process performance, such as gas production, acetic acid production, COD, phosphorus, nitrogen and suspended solids loadings and % COD removal were also monitored. The response of both biochemical and conventional parameters to changing process conditions was then compared. Alkaline phosphatase activity exhibited the highest activity over the entire study perioda A high suspended solids loading was observed to upset the system in terms of gas production, acetic acid production and % COD removala The initial rate of increase in alkaline phosphatase activity following an increase in loading was four times as great during process upset than under conditions of good performance. The change in enzyme actiVity was also more sensitive to process upset than changes in acetic acid production. The change in ATP content of the sludge with time suggested that enzyme actiVity was changing independently of the actual viable biomass present. The bacterial composition of the anaerobic sludge granules was similar to that of other sludge bed systems, at the light and scanning electron microscope level. Isolated serum bottle cultures produced several acids involved in anaerobic carbohydrate metabolism. The overall performance of the UASB system indicated that higher loadings of soluble nutrients could have been tolerated by the system.

A comparison of two bench-scale anaerobic systems used for the treatment of dairy effluents

The objective of this work was to compare two anaerobic reactor conflgurations, a hybrid upflow anaerobic sludge blanket (UASBh) reactor and an anaerobic sequencing batch reactor with immobilised biomass (ASBBR) treating dairy effluents. The reactors were fed with effluent from the milk pasteurisation process (effluent 1-E1) and later with effluent from the same process combined with the one from the cheese manufacturing (effluent 2-E2). The ASBBR reactor showed average organic matter removal efficiency of 95.2% for E1 and 93.5% for E2, while the hybrid UASB reactor showed removal efficiencies of 90.3% and 80.1% respectively.

Fermentação metanogênica mesofílica de melaço e termofílica de vinhaça em reatores UASB

Pós-graduação em Microbiologia Agropecuária - FCAV

Performance evaluation and phylogenetic characterization of anaerobic fluidized bed reactors using ground tire and pet as support materials for biohydrogen production

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Constructed Wetland for Treating Effluent from Subtropical Aquaculture Farm

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Sulfamethoxazole and ciprofloxacin removal using a horizontal-flow anaerobic immobilized biomass reactor

The antibiotics sulfamethoxazole (SMTX) and ciprofloxacin (CIP) are commonly used in human and veterinary medicine, which explains their occurrence in wastewater. Anaerobic reactors are low-cost, simple and suitable technology to wastewater treatment, but there is a lack of studies related to the removal efficiency of antibiotics. To overcome this knowledge gap, the objective of this study was to evaluate the removal kinetics of SMTX and CIP using a horizontal-flow anaerobic immobilized biomass reactor. Two different concentrations were evaluated, for SMTX 20 and 40 μg L(-1); for CIP 2.0 and 5.0 μg L(-1). The affluent and effluent analysis was carried out in liquid chromatography/tandem mass spectrometry (LC-MS/MS) with the sample preparation procedure using an off-line solid-phase extraction. This method was developed, validated and successfully applied for monitoring the affluent and effluent samples. The removal efficiency found for both antibiotics at the two concentrations studied was 97%. Chemical oxygen demand (COD) exhibited kinetic constants that were different from that observed for the antibiotics, indicating the absence of co-metabolism. Also, though the antibiotic concentration was increased, there was no inhibitory effect in the removal of COD and antibiotics.