Campos, J. L., del Rio, A. V., Pedrouso, A., Raux, P., Giustinianovich, E. A., & Mosquera-Corral, A. (2017). Granular biomass floatation: A simple kinetic/stoichiometric explanation. Chem. Eng. J., 311, 63–71.
Abstract: Floatation events are commonly observed in anammox, denitrifying and anaerobic granular systems mostly subjected to overloading conditions. Although several operational strategies have been proposed to avoid floatation of granular biomass, until now, there is no consensus about the conditions responsible for this phenomenon. In the present study, a simple explanation based on kinetic and stoichiometric principles defining the aforementioned processes is provided. The operational zones corresponding to evaluated parameters where risk of floatation exists are defined as a function of substrate concentration in the bulk liquid and the radius of the granule. Moreover, the possible control of biomass floatation by changing the operating temperature was analyzed. Defined operational zones and profiles fit data reported in literature for granular biomass floatation events. From the study the most influencing parameter on floatation occurrence has been identified as the substrate concentration in the bulk media. (C) 2016 Elsevier B.V. All rights reserved.
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Giustinianovich, E. A., Campos, J. L., & Roeckel, M. D. (2016). The presence of organic matter during autotrophic nitrogen removal: Problem or opportunity? Sep. Purif. Technol., 166, 102–108.
Abstract: The simultaneous nitrification, Anammox and denitrification (SNAD) process discovered six years ago is an adaptation of the autotrophic denitrification process that allows for treating nitrogen-rich wastewater streams with moderate amounts of organic carbon. Several authors have noted that it is possible to utilize organic carbon to promote nitrogen removal via the action of denitrifying microorganisms, which can remove the remnant nitrate produced by Anammox bacteria. Thus, SNAD systems can achieve nitrogen removal efficiencies higher than 89%, which is what is expected under autotrophic conditions. Three bacterial groups are responsible for SNAD reactions: ammonium-oxidizing bacteria (AOB), anaerobic ammonium-oxidizing bacteria (AnAOB) and heterotrophic bacteria (HB). Because HB will compete with AOB and AnAOB for oxygen and nitrite, respectively, the system should be operated in such way that a balance among the different bacterial populations is achieved. Here, the results reported in the literature are analyzed to define suitable characteristics of effluents for treatment and operational conditions to allow the SNAD process to be carried out with different types of technologies. (C) 2016 Elsevier B.V. All rights reserved.
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Giustinianovich, E. A., Campos, J. L., Roeckel, M. D., Estrada, A. J., Mosquera-Corral, A., & del Rio, A. V. (2018). Influence of biomass acclimation on the performance of a partial nitritation-anammox reactor treating industrial saline effluents. Chemosphere, 194, 131–138.
Abstract: The performance of the partial nitritation/anammox processes was evaluated for the treatment of fish canning effluents. A sequencing batch reactor (SBR) was fed with industrial wastewater, with variable salt and total ammonium nitrogen (TAN) concentrations in the range of 1.75-18.00 g-NaCl L-1 and 112 – 267 mg-TAN L-1. The SBR operation was divided into two experiments: (A) progressive increase of salt concentrations from 1.75 to 1833 g-NaCl L-1; (B) direct application of high salt concentration (18 g-NaCl L-1). The progressive increase of NaCl concentration provoked the inhibition of the anammox biomass by up to 94% when 18 g-NaCl L-1 were added. The stable operation of the processes was achieved after 154 days when the nitrogen removal rate was 0.021 +/- 0.007 g N/L.d (corresponding to 30% of removal efficiency). To avoid the development of NOB activity at low salt concentrations and to stabilize the performance of the processes dissolved oxygen was supplied by intermittent aeration. A greater removal rate of 0.029 +/- 0.017 g-N L-1 d(-1) was obtained with direct exposure of the inoculum to 18 g-NaCl L-1 in less than 40 days. Also, higher specific activities than those from the inoculum were achieved for salt concentrations of 15 and 20 g-NaCl L-1 after 39 days of operation. This first study of the performance of the partial nitritation/anammox processes, to treat saline wastewaters, indicates that the acclimation period can be avoided to shorten the start-up period for industrial application purposes. Nevertheless, further experiments are needed in order to improve the efficiency of the processes. (C) 2017 Elsevier Ltd. All rights reserved.
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