933 resultados para sequencing batch reactors


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Petasis and Ugi reactions are used successively without intermediate purification, effectively accomplishing a six-component reaction. The examined reactions are transferred from traditional batch reactors to an automated continuous flow microreactor setup, where optimization and kinetic analyses are performed, proposed mechanisms evaluated, and rate-limiting steps determined.

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Among the waste generated in the petrochemical industry water associated with oil production is the most important. It is considered one of the great challenges due to the presence of considered toxic chemicals present in this composition. The presence of these substances difficult to reuse the water associated with the enhanced recovery processes, so that prior to their reuse or disposal, treatment is necessary. This paper aimed to study the removal efficiency of chemical species: Ba2+, Ni2+, Cd2+, Cu2+, Cr3+, Sr2+ and Zn2+, present in the composition of the water associated with oil production by electrocoagulation. The evaluation of removal of these chemical species was performed by laboratory tests using electrochemical batch reactors and continuous flow. Initial tests were performed with electrocoagulation of synthetic wastewater in batch reactor using iron electrode. Results of removal of Zn2+ and Ni2+ were 78 % and 59 % respectively. While the percentage of removed Ba2+ was 19 % by 30 minutes of treatment and by applying current of 1.10 A. The tests were performed on effluent batch reactor applying the electrochemical technique with stainless steel electrodes 304, the objective was to remove part of the dispersed oil and also of organic compounds in the effluent. Under the experimental conditions used, the maximum result was obtained TOG was 60 % and TOC was approximately 50 % compared to the initial concentration. In the experiments carried out in continuous reactor, with effluent semisynthetic, have been used electrodes of iron and aluminum and the results were 100 % removal of Cd2+, Cu2+, Cr3+ and Zn2+ and 77 % of Sr2+. These percentages were only attainable through the use of the iron electrode. However, when the electrode was replaced by aluminum, there was a reduction in the percentage of removal to 65 %, using the same flow rate and current. Therefore according to the results obtained using the iron electrode was more effective in removing these metals and the conditions of lower current and lower flow rate was satisfactory, as observed in the experimental design adopted

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This study investigated the influence of the molar ratio, the phosphorus initial concentration, the mixture gradient, mixing time, pH and the secondary nucleation on struvite s crystallization in synthetic water in batch reactors. The study was divided into two stages. The first investigated struvite s crystallization at different Mg:N:P molar ratios and at different initial concentrations of magnesium, nitrogen and phosphorus. It was also evaluated the importance of secondary nucleation on the struvite s crystallization. In the second, five parameters were tested to evaluate their influence on the struvite s crystallization, which were: Mg:N:P molar ratio, initial concentration of phosphate, mixing time, mixture gradient and pH. The best conditions for struvite s crystallization were: Mg:N:P = 1,3:1:1 molar ratio; mixture gradient = 60 rpm, pH = 10.0, mixing time = 5 minutes and high initial concentrations of the constituent ions of struvite. Furthermore, the use of struvite crystals as seed influenced positively on the struvite s crystallization

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

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The biological nitritation/denitritation process in the removal of organic matter and nitrogen in a landfill leachate was studied, using an activated sludge sequencing batch reactor. Treatment cycles were formed by an anoxic and an aerobic phases, in which the conditions for oxidation of the influent N load and the prevalence of nitrite concentration at the end of aerobic treatment cycles were determined, as well as the use of organic matter present in the leachate as a carbon source for denitrifying organisms in the anoxic stage. The removal efficiencies of N-NO 2-at the end of the anoxic process (48h) ranged between 14 and 30%, indicating low availability of biodegradable organic matter in the leachate. As for the accumulation of N-NO 2-at the end of the aerobic phase (48h) of treatment cycles, imbalances were not observed, while 100% removal efficiencies of N and specific nitritation rates from 0.095 to 0.158kgN-NH 3/kgSSV per day were recorded, demonstrating the applicability of simplified nitrification in the treatment of effluents with low C/N ratios.

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Pós-graduação em Zootecnia - FCAV

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This study aims to analyze the feasibility of using predictive techniques like thermography, vibration analysis, eddy current, liquid penetrant, visual examination and ultrasound in equipment as batch reactors of the type used in a biodiesel production company. This study is based on: analysis of the practices of corrective and preventive maintenance commonly adopted in the company in question, the cost and time spent for such activities and the potential savings and revenue generation that can be after implementation of these techniques on the analysis of maintenance current

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The volume of liquid effluent generated in cattle slaughterhouses is quite high and cannot be released untreated in water bodies due to its high pollution load of predominantly organic origin. To minimize the environmental impacts of its industrial wastewater and meet the local environmental legislation, abattoirs shall make the treatment of these effluents. The present work aims to develop the study of a reactor by sequential batch pilot scale, in order to optimize their performance in treating wastewater from a cattle slaughterhouse. The treatment system used was developed and installed in the Laboratory of Wastewater Treatment, in Faculty of Science and Technology UNESP, Presidente Prudente campus. The procedure used followed the operation of sequential batch reactors, in which all processes and treatment operations occurring sequentially in a single unit, by establishing specific operating cycles, which comprise the following separated phases: aerobic reaction, anoxic reaction, sedimentation and emptying. Aiming to improve the quality of treatment was planned the addition of coagulant Poly Aluminum Chloride (PAC) in the reactor, by determining their optimal dosage by Jar-test trials. Were prepared four steps with specific operating cycles: step one or acclimatization (10 hour of aeration, one hour and 30 minutes of sedimentation and 30 minutes for exchanging the effluent); step 2 (6 hours of aeration or aerobic phase, 4 hours and 45 minutes of stirring or anoxic phase and 1 hour and 15 minutes for sedimentation and exchange effluent); step 3 (2 hours and 30 minutes of aeration, 8 hours and 15 minutes of stirring and 1 hour and 15 minutes for sedimentation and exchange) and step 4 (2 hours of aeration, 8 hours and 45 minutes of stirring and 1 hour and 15 minutes for sedimentation and exchange)... (Complete abstract click electronic access below)

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This research aims at the study of treatment of clothes washing water through biological treatment, for the purpose of evaluating the reduction of phosphorus to make it suitable for a posterior treatment of physical-chemical. For this purpose it was employed a sequencing batch reactor, consisting of aerobic and anaerobic phases. During the project it was verified not only the reduction of phosphorus (removal of 30 to 50%) but also the reduction of BOD, COD, Turbidity and Nitrate (removal of 38 to 36%, 34 to 41%, 72,3 to 75% and 57,8 to 60% respectively), which demonstrates that the proposed treatment can assist advanced treatments of water for its non potable reuse

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The aim of this work was to identify groups of microorganisms that are capable of degrading organic matter utilizing sulfate as an electron acceptor. The assay applied for this purpose consisted of running batch reactors and monitoring lactate consumption, sulfate reduction and sulfide production. A portion of the lactate added to the batch reactors was consumed, and the remainder was converted into acetic, propionic and butyric acid after 111 hours of operation These results indicate the presence of sulfate-reducing bacteria (SRB) catalyzing both complete and incomplete oxidation of organic substrates. The sulfate removal efficiency was 49.5% after 1335 hours of operation under an initial sulfate concentration of 1123 mg/L. The SRB concentrations determined by the most probable number (MPN) method were 9.0x10(7) cells/mL at the beginning of the assay and 8.0x10(5) cells/mL after 738 hours of operation.

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The aim of this work was to investigate the effect of different feeding times (2, 4 and 6 h) and applied volumetric organic loads (4.5, 6.0 and 7.5 gCOD L-1 day(-1)) on the performance of an anaerobic sequencing batch biofilm reactor (AnSBBR) treating effluent from biodiesel production. Polyurethane foam cubes were used as inert support in the reactor, and mixing was accomplished by recirculating the liquid phase. The effect of feeding time on reactor performance showed to be more pronounced at higher values of applied volumetric organic loads (AVOLs). Highest organic material removal efficiencies achieved at AVOL of 4.5 gCOD L-1 day(-1) were 87 % at 4-h feeding against 84 % at 2-h and 6-h feeding. At AVOL of 6.0 gCOD L-1 day(-1), highest organic material removal efficiencies achieved with 4-h and 6-h feeding were 84 %, against 71 % at 2-h feeding. At AVOL of 7.5 gCOD L-1 day(-1), organic material removal efficiency achieved with 4-h feeding was 77 %. Hence, longer feeding times favored minimization of total volatile acids concentration during the cycle as well as in the effluent, guaranteeing process stability and safety.