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Search Results: 1 - 10 of 1767 matches for " Eugenio Foresti "
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Arnaldo Sarti,Eugenio Foresti
Holos Environment , 2009,
Abstract: This paper presents and discusses the potential for use of pilot-scale anaerobic sequencing batch biofilm reactors (ASBBR) for the treatment of industrial wastewater containing high sulfate concentration. The pilot-scale ASBBR reactor (total volume=1.2 m3) containing biomass immobilized in inert support (mineral coal) was operated at sulfate loading rates varying from 0.15 to 1.90 kgSO4-2/cycle (cycle of 48h) corresponding to sulfate concentrations of 0.25 to 3.0 gSO4-2.L-1. Domestic sewage and ethanol were utilized as electron donors for sulfate reduction. The mean sulfate removal efficiencies remained in the range of 88 to 92% in the several sulfate concentrations obtained from 92 operational cycles. As post-treatment unit for the generated effluents by the sulfate reduction was used another reactor ASBBR in pilot-scale (total volume=385,0 L) with same inert support for biomass immobilization and different granulometry. The mean COD removal (mean influent=1450 mg.L-1) achieved 88% and total sulfide concentrations (H2S, HS , S2 ) remained in the range of 41 to 71 mg.L-1 during the 35 operational cycles of 48 h. The results demonstrated that the use of ASBBR reactors is an alternative potential for the sulfate removal and as post-treatment of generated effluent. = Este trabalho apresenta e discute o potencial de uso de reatores anaeróbios operados em bateladas seqüenciais com biomassa imobilizada (ASBBR), em escala piloto, no tratamento de água residuária industrial contendo elevadas concentra es de sulfato. No ASBBR, com volume total de 1,2 m3, preenchido com carv o mineral (meio suporte) foram aplicadas cargas de sulfato de 0,15 a 1,90 kg/ciclo com dura o de ciclo de 48 h, correspondendo, respectivamente, às concentra es de sulfato no afluente de 0,25 a 3,0 g.L-1. O esgoto sanitário e etanol foram usados como doadores de elétrons para a redu o do sulfato. As eficiências médias na redu o de sulfato ficaram entre 88 e 92% nos 92 ciclos operacionais. Como pós-tratamento dos efluentes gerados pela redu o de sulfato empregou-se outro reator ASBBR com volume total de 385,0 L e mesmo meio suporte para imobiliza o da biomassa, mas com diferente granulometria. A remo o média de DQO (valor médio afluente: 1450 mg.L-1) foi de 88%, enquanto as concentra es de sulfetos totais (H2S, HS , S2 ) mantiveram-se entre a faixa de 41 e 71 mg.L-1 nos 35 ciclos operacionais de 48h. Os resultados obtidos permitiram concluir que o uso de reatores ASBBR constitui-se em potencial alternativa tanto para a remo o de sulfatos, como no pós-tratamento dos efluentes gerados.
Efeito do bicarbonato de sódio no tratamento de vinha?a em AnSBBR operado a 55 e 35oC
D?ll, Maria Magdalena Ribas;Foresti, Eugenio;
Engenharia Sanitaria e Ambiental , 2010, DOI: 10.1590/S1413-41522010000300011
Abstract: the influence of the sodium bicarbonate (nahco3) on the performance of an anaerobic sequencing batch biofilm reactor treating vinasse at 55 and 35oc was evaluated. the reactor was filled with polyurethane foam and agitated at 300 rpm. the acclimatization period at 55oc lasted 50 days, and the reactor was fed with vinasse (cod from 0.3 to 1.0 g/l). a previous enrichment of methanogenic population was provided for the reactor operated at 35oc, feeding it with an ethanol based substrate (2.5 gcod/l) during 21 days. further on, organic loading rates (olr) ranging from 0.85 to 5.70 gcod/l.d were applied to the reactor at 55oc, supplemented with 1.2 to 0.4 ghco3-/gcod. at 35oc the reactor was subjected to olr ranging from 2.85 to 36.0 gcod/l.d with 0.4 to 0.2 ghco3-/gcod. cod removal ranged from 43 to 78% at 55oc and from 75 to 85% at 35oc. alkalinity supplementation was found to be essential for process stability, but the amount required was lower at 35oc.
A novel aerobic-anoxic biological filter for nitrogen removal from UASB effluent using biogas compounds as electron donors for denitrification
Rodríguez Victoria,Jenny; Foresti,Eugenio;
Revista Facultad de Ingeniería Universidad de Antioquia , 2011,
Abstract: the performance of a new trickling filter (tf) configuration composed of an upper compartment for nitrification and a lower compartment for denitrification of effluent from a uasb reactor treating domestic sewage was evaluated. the tf was packed with new plastic material characterized by its durability and high percentage of void spaces. the feasibility of using the reduced compounds present in the biogas produced by a uasb reactor as electron donor for denitrification was also evaluated. efficient nitrification and denitrification was achieved for the mean hydraulic (5.6 m3 m-2 d-1), organic (0.26 kg cod m-3 d-1) and ammonia-n (0.08 kg m-3 d-1) loading rates applied, resulting in ammonia-n removal ranging from 60 to 74%. the final effluent presented ammonia-n lower than 13 mg l-1. despite the presence of dissolved oxygen (do) in the denitrification compartment, its performance was considered quite satisfactory and final nitrate concentrations were lower than 10 mg l-1. the results indicate that methane was the main electron donor used for denitrification. additionally, denitrification can probably be improved by avoiding high do concentration in the denitrification compartment and by enhancing biogas transfer in the anoxic zone.
Influence of the COD to sulphate ratio on the anaerobic organic matter degradation kinetics
Francisco José Vela, Marcelo Zaiat, Eugenio Foresti
Water SA , 2002,
Abstract: The influence of the COD to sulphate ratio on the substrate consumption kinetic parameters was evaluated using a differential reactor filled with polyurethane foam matrices, taken from a horizontal-flow anaerobic immobilised biomass (HAIB) reactor. Experiments were carried out with synthetic substrate containing glucose, ammonium acetate and methanol, besides sodium bicarbonate. Micronutrients were provided by adding salts and trace metals from a stock solution. The influent chemical oxygen demand (COD) was maintained as constant as possible around 2 000 mg·l-1 in all the experiments. The reactors were subjected to increasing sulphate concentrations from 100 to 2 800 mg·l-1. First-order apparent kinetic parameters (K1 a pp ) decreased from 1.96 x 10-4 to 1.55 x 10-4l·mg VSS-1·h-1 as the COD to sulphate ratio decreased from 22.6 to 0.8. The progressive but moderate inhibition of the organic matter conversion observed indicates that high sulphate concentrations can be accommodated in HAIB reactors even at very low COD to sulphate ratios. WaterSA Vol.28(2) 2002: 213-216
Performance of anaerobic sequencing batch reactors (pilot-scale) in domestic sewage treatment
Arnaldo Sarti,Marcelo Zaiat,Eugenio Foresti
Semina : Ciências Exatas e Tecnológicas , 2005,
Abstract: This study shows the results obtained during 70 days using four pilot scale anaerobic sequencing batch reactors, for sewage system treatment of the campus of the University of S o Paulo in S o Carlos – SP. Each reactor system with 1.2 m3 of total volume, was designed for the treatment of 1.95 m3d3 of domestic sewage, with geometrical conceptions (ratio H-height/D-diameter), mechanical conceptions (mechanical mixing or liquid re-circulation) and different biomass retention type. Three of them were ASBR (AnaerobicSequencing Batch Reactor) with granular biomass and another one was an ASBBR (Anaerobic Sequencing Batch Biofilm Reactor) with biomass consisting of cubic matrices of polyurethane foam. The reactors were inoculated and operated within an 8-hour batch cycle. The reactors monitoring included the oxygen chemical demand (OCD), pH, total suspended solids (TSS) and volatile suspended solids, volatile fatty acids, alkalinity to bicarbonate and methane concentration. Both ASBR reactors with liquid re-circulation did not show a satisfactory performance. The average values of OCD and TSS removal were close to 40% and 60% respectively. In the ASBR reactors with mechanical mixing and ASBBR with immobilized biomass, showed better results. The ASBBR reactor reached average efficiency of 61% and 75% in OCD and TSS removal, while in the ASBR with mechanical mixing, it reached 60% and 79%, respectively.
Avalia??o da acurácia de diversos métodos para determina??o de ácidos graxos voláteis e alcalinidade a bicarbonato para monitoramento de reatores anaeróbios
Ribas, Maria Magdalena Ferreira;Moraes, Elizabeth de Mattos;Foresti, Eugenio;
Engenharia Sanitaria e Ambiental , 2007, DOI: 10.1590/S1413-41522007000300002
Abstract: anaerobic treatment systems are sensitive to the environmental condition changes. such changes may have influence on the metabolism of the microorganisms responsible for the process stability. the aims of this work were (i) to evaluate the accuracy of methods to determine control parameters volatile fatty acids (vfa) and bicarbonate alkalinity (ba) in samples prepared with concentrations from 50 to 1000 mg/l and, (ii) to verify different procedures of the co2 removal formed during the acid titration of the samples. from the tukey statistical test applied to the obtained results it was observed that the kapp and dilallo & albertson methods using sonic equipment to remove co2 from the liquid presented better results for vfa. the conductivity, kapp and jenkins methods were considered the most reliable for ba determination.
Influência do tempo de deten??o e da taxa de aplica??o de lodo na hidrólise e acidogênese de lodo primário
Coelho, André Luiz da S. S;Foresti, Eugenio;
Engenharia Sanitaria e Ambiental , 2005, DOI: 10.1590/S1413-41522005000200012
Abstract: the main aim of the research was to evaluate the influence of the sludge retention time (srt) and application rate (ar) on hydrolysis and acidogenesis of primary sludge from a sewage treatment plant. the study was carry out using a lab-scale hydrolytic sludge digestor (hsd) of 1.3 l useful volume, operated in sequencing batch mode, subjected to different sludge application rates (ar), expressed as the ratio between total cod and vss concentration applied to each batch, along different sludge retention time (srt). the values of applied ar expressed as kg cod/kg ssv.d were 1.7, 2.1, and 2.7. the reactor performance was evaluated in terms of filtered cod (and hydrolysis rate) and vfa (and acidogenesis rate) production, for each srt tested. vfa composition was also determined. the results allowed concluding that the hydrolysis rate was only satisfactory for the ar of 2.1 and 2.7 gcodt/gvss.d. the optimum acidogenesis rate was obtained at the srt of two days for all the essays applied. vfa production was directly proportional to the applied ar only for the optimum acidogenesis rate period, at srt of two days approximately, tending to decrease for the higher values of srt. acetic and propionic acids were the main vfa produced by the hsd reactor.
Tratamento de esgoto sanitário utilizando reatores anaeróbios operados em bateladas sequenciais (escala piloto)
Sarti, Arnaldo;Sakamoto, Isabel Kimiko;Varesche, Maria Bernadete Amancio;Zaiat, Marcelo;Foresti, Eugenio;
Engenharia Sanitaria e Ambiental , 2006, DOI: 10.1590/S1413-41522006000100010
Abstract: the performances of two anaerobic sequencing batch reactors (1.2 m3) containing biomass immobilized in inert support and as granular sludge in the treatment of domestic sewage from the campus of s?o carlos-university of s?o paulo were evaluated. the experimental phase lasted seventy days. during this period, the reactors presented quite similar performances in respect to cod and total suspended solids removal, achieving average efficiencies of approximately 60% and 75%, respectively. the analysis using molecular biology techniques on biomass samples taken at 35th and 70th showed differences in the bacterial community in the reactors indicating that the type of biomass immobilization selected the populations differently. a higher similarity was found for the archaea domain probably because these microorganisms utilize specific substrates formed at the end of the anaerobic process.
Remo??o de sulfato de águas residuárias industriais em reator anaeróbio de leito fixo operado em bateladas sequenciais
Sarti, Arnaldo;Silva, Ariovaldo José da;C?rtes, Roberto Sarti;Foresti, Eugenio;
Engenharia Sanitaria e Ambiental , 2008, DOI: 10.1590/S1413-41522008000100003
Abstract: the potential use of an anaerobic sequencing batch biofilm reactor (asbbr) in pilot-scale for the treatment of a sulfate-rich industrial wastewater was evaluated. the pilot 1.2 m3 asbbr reactor was filled with mineral coal for biomass immobilization (fixed film). the sulfate loading rates applied were 0.15; 0.30; 0.65; 1.30 and 1.90 kg so4-2/cycle (or batch). each cycle lasted 48 h. the influent concentrations were, respectively, 0.25; 0.50; 1.0; 2.0 and 3.0 gso4-2.l-1. ethanol was used as electron donor for sulfate reduction. the reactor operated at ambient temperature (29±8oc), and the mean efficiencies of sulfate removal were in the range 88 to 92% in the 92 run cycles. the total operating period comprised 275 days. based on the results obtained in this research, it could be concluded that the asbbr can be an efficient alternative for the removal of sulfate from other industrial wastewaters with similar characteristics.
Morphological study of biomass during the start-up period of a fixed-bed anaerobic reactor treating domestic sewage
Lima, Cláudio Antonio Andrade;Ribeiro, Rogers;Foresti, Eugenio;Zaiat, Marcelo;
Brazilian Archives of Biology and Technology , 2005, DOI: 10.1590/S1516-89132005000600020
Abstract: this work focused on a morphological study of the microorganisms attached to polyurethane foam matrices in a horizontal-flow anaerobic immobilized biomass (haib) reactor treating domestic sewage. the experiments consisted of monitoring the biomass colonization process of foam matrices in terms of the amount of retained biomass and the morphological characteristics of the cells attached to the support during the start-up period. non-fluorescent rods and cocci were found to predominate in the process of attachment to the polyurethane foam surface. from the 10th week of operation onwards, an increase was observed in the morphological diversity, mainly due to rods, cocci, and methanosaeta-like archaeal cells. hydrodynamic problems, such as bed clogging and channeling occurred in the fixed-bed reactor, mainly due to the production of extracellular polymeric substances and their accumulation in the interstices of the bed causing a gradual deterioration of its performance, which eventually led to the system's collapse. these results demonstrated the importance and usefulness of monitoring the dynamics of the formation of biofilm during the start-up period of haib reactors, since it allowed the identification of operational problems.
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