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Silva R.C.,Instituto Maua Of Tecnologia Eem Imt | Rodrigues J.A.D.,Instituto Maua Of Tecnologia Eem Imt | Ratusznei S.M.,Instituto Maua Of Tecnologia Eem Imt | Zaiat M.,University of Sao Paulo
Applied Biochemistry and Biotechnology | Year: 2013

A mechanically stirred anaerobic sequencing batch reactor (5 L, 30 C) containing granular biomass was used to treat the effluent of an industrial biodiesel production process with the purpose to produce methane. Process stability and efficiency were analyzed as a function of applied volumetric organic load (AVOL of 1,000 to 3,000 mgCOD/L), reactor feed time, and cycle length (8-h cycles with 10-min or 4-h feeding and 4-h cycles with 10-min or 2-h feeding). Batch operations (B) with 1,000 to 3,000 mgCOD/L involved 10-min feeding/discharge: (1) 1.0-L influent with 4-h cycle and (2) 2.0-L influent with 8-h cycle. Fed-batch operations (FB) with 1,000 to 3,000 mgCOD/L involved 10-min discharge and the following feeding: (1) 1.0-L influent in 2 h with 4-h cycle and (2) 2.0-L influent in 4 h with 8-h cycle. At 1,000 mgCOD/L (AVOL of 18 to 1.29 gCOD/L day), kinetic parameter values were 1.03 and 0.92 h-1 at conditions B-1000-4 h and FB-1000-8/4 h, respectively. At both conditions, removal efficiency was 88 %, and cycle length could be reduced to 3 h (B-1000-4 h) and 5 h (FB-1000-8/4 h). At 2,000 mgCOD/L (AVOL of 2.38 to 2.52 gCOD/L day), kinetic parameter values were 1.08 and 0.99 h-1 at conditions B-2000-4/2 h and FB-2000-8/4 h, respectively, and removal efficiencies were 83 and 81 %. Cycle length could be reduced to 3 h (B-2000-4/2 h) and 6 h (FB-2000-8/4 h). At 3,000 mgCOD/L (AVOL of 3.71 to 3.89 gCOD/L day), conditions allowing stable operation were B-3000-4 h, FB-3000-8/4 h, and FB-3000-4/2 h. Stability could not be obtained at condition B-3000-8 h, and the best results were obtained at condition FB-3000-8/4 h. Specific methane production ranged from 41.1 to 93.7 NmLCH4/gCOD, demonstrating reactor application potential and operation flexibility. © 2013 Springer Science+Business Media New York. Source


Contrera R.C.,University of Sao Paulo | da Cruz Silva K.C.,University of Sao Paulo | Morita D.M.,University of Sao Paulo | Domingues Rodrigues J.A.,Instituto Maua Of Tecnologia Eem Imt | And 2 more authors.
Journal of Environmental Management | Year: 2014

This paper reports the kinetics evaluation of landfill leachate anaerobic treatment in a pilot-scale Anaerobic Sequence Batch Biofilm Reactor (AnSBBR). The experiment was carried out at room temperature (23.8±2.1°C) in the landfill area in São Carlos-SP, Brazil. Biomass from the bottom of a local landfill leachate stabilization pond was used as inoculum. After acclimated and utilizing leachate directly from the landfill, the AnSBBR presented efficiency over 70%, in terms of COD removal, with influent COD ranging from 4825mgL-1 to 12,330mgL-1. To evaluate the kinetics of landfill leachate treatment, temporal profiles of CODFilt. concentration were performed and a first-order kinetics model was adjusted for substrate consumption, obtaining an average k1=4.40×10-5LmgTVS-1d-1, corrected to 25°C. Considering the temperature variations, a temperature-activity coefficient θ=1.07 was obtained. Statistical "Randomness" and "F" tests were used to successfully validate the model considered. Thus, the results demonstrate that the first-order kinetic model is adequate to model the anaerobic treatment of the landfill leachate in the AnSBBR. © 2014 Elsevier Ltd. Source


Canto C.S.A.,Instituto Maua Of Tecnologia Eem Imt | Ratusznei S.M.,Instituto Maua Of Tecnologia Eem Imt | Rodrigues J.A.D.,Instituto Maua Of Tecnologia Eem Imt | Zaiat M.,University of Sao Paulo | Foresti E.,University of Sao Paulo
Afinidad | Year: 2010

Ammonium nitrogen removal from a synthetic wastewater by nitrification and denitrification processes were performed in a sequencing batch biofilm reactor containing immobilized biomass on polyurethane foam with circulation of the liquid-phase. It was analyzed the effect of four external carbon sources (ethanol, acetate, carbon synthetic medium and methanol) acting as electron donors in the denitrifying process. The experiments were conducted with intermittent aeration and operated at 30±1°C in 8-h cycles. The synthetic wastewater (100 mgCOD/L and 50 mgNH 4 +-N/L) was added batch-wise, while the external carbon sources were added fed-batch-wise during the periods where aeration was suspended. Ammonium nitrogen removal efficiencies obtained were 95.7, 94.3 and 97.5% for ethanol, acetate and carbon synthetic medium, respectively. As to nitrite, nitrate and ammonium nitrogen effluent concentrations, the results obtained were, respectively: 0.1, 5.7 and 1.4 mg/L for ethanol; 0.2, 4.1 and 1.8 mg/L for acetate and 0.2, 6.7 and 0.8 for carbon synthetic medium. On the other hand using methanol, even at low concentrations (50% of the stoichiometric value calculated for complete denitrification), resulted in increasing accumulation of nitrate and ammonium nitrogen in the effluent over time. Source


Archilha N.C.,Instituto Maua Of Tecnologia Eem Imt | Canto C.S.A.,Instituto Maua Of Tecnologia Eem Imt | Ratusznei S.M.,Instituto Maua Of Tecnologia Eem Imt | Rodrigues J.A.D.,Instituto Maua Of Tecnologia Eem Imt | And 2 more authors.
Journal of Environmental Management | Year: 2010

The objective of this work was to analyze the effect of the interaction between feeding strategy and COD/sulfate ratio on the removal efficiency of sulfate and organic matter from a synthetic wastewater. An anaerobic sequencing batch reactor with recirculation of the liquid phase and containing immobilized biomass on polyurethane foam (AnSBBR) was used. The AnSBBR with a total volume of 3.7L, treated 2.0L synthetic wastewater in 8-h cycles at 30±1°C and was inoculated with anaerobic biomass from a UASB. Two feeding strategies were assessed: (a) batch and (b) batch followed by fed-batch. In strategy (a) the reactor was fed in 10min with 2L wastewater containing sulfate and carbon sources. In strategy (b) 1.2L wastewater (containing only the sulfate source) was fed during the first 10min of the cycle and the remaining 0.8L (containing only the carbon source) in 240min. The COD/sulfate ratios assessed were 1 and 3. Based on these values and on the concentrations of organic matter (0.5-11.25gCOD/L) and sulfate (0.5 and 2.5gSO42-/L), the sulfate and organic matter loading rates applied equaled 1.5 and 4.5gSO42-/Ld for sulfate and 1.5, 4.5 and 13.5gCOD/Ld for organic matter. After stabilization of the system time profiles were run of monitored parameters (COD, sulfate, sulfide and sulfite). In general, the reactor showed to be robust for use in the anaerobic treatment of wastewaters containing sulfate. Gradual feeding (strategy b) of the carbon source favored sulfate reduction, resulting in sulfate removal efficiencies of 84-98% and organic matter removal efficiencies of 48-95%. The best results were observed under COD/sulfate ratio equal to 1 (loading rates of 1.5 and 4.5gSO42-/Ld for sulfate, and 1.5 and 4.5gCOD/Ld for organic matter). When COD/sulfate ratio was 3 (loading rates of 1.5and 4.5gSO42-/Ld for sulfate, and 4.5 and 13.5gCOD/Ld for organic matter) the effect of feed mode became less significant. These results show that the strategy batch followed by fed-batch is more advantageous for COD/sulfate ratios near the stoichiometric value (0.67) and higher organic matter and sulfate concentrations. © 2010 Elsevier Ltd. Source


De Novaes L.F.,University of Sao Paulo | Borges L.O.,University of Sao Paulo | Rodrigues J.A.D.,Instituto Maua Of Tecnologia Eem Imt | Ratusznei S.M.,Instituto Maua Of Tecnologia Eem Imt | And 2 more authors.
Applied Biochemistry and Biotechnology | Year: 2010

Many lab-scale studies have been carried out regarding the effect of feed strategy on the performance of anaerobic sequencing batch reactors (ASBR); however, more detailed pilot-scale studies should be performed to assess the real applicability of this type of operation. Therefore, the objective of this work was to assess the effect of feed strategy or fill time in a 1-m3 mechanically stirred pilot-scale sequencing batch reactor, treating 0.65 m 3 sanitary wastewater in 8-h cycles at ambient temperature. Two reactor configurations were used: one containing granular biomass (denominated ASBR) and the other immobilized biomass on polyurethane foam as inert support (denominated anaerobic sequencing batch biofilm reactor (AnSBBR)). The reactors were operated under five distinct feed strategies, namely: typical batch and fed-batch for 25%, 50%, 75%, and 100% of the cycle length. Stirring frequency in the ASBR was 40 rpm with two flat-blade turbine impellers and 80 rpm in the AnSBBR with two helix impellers. The results showed that both the ASBR and AnSBBR when operated under typical batch, fed-batch for 50% and 75% of the cycle length, presented improved organic matter removal efficiencies, without significant differences in performance, thus showing important operational flexibility. In addition, the reactors presented operation stability under all conditions. © Humana Press 2009. Source

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