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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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Pichel, A., Fra, A., Morales, N., Campos, J. L., Mendez, R., Mosquera-Corral, A., et al. (2021). Is the ammonia stripping pre-treatment suitable for the nitrogen removal via partial nitritation-anammox of OFMSW digestate? J. Hazard. Mater., 403, 123458.
Abstract: Treating the organic fraction of municipal solid waste (OFMSW) can be performed by coupling the anaerobic digestion (AD) and partial nitritation-anammox (PN-AMX) processes for organic matter and nitrogen removal, respectively. Besides, an ammonia stripping (AS) step before the AD benefit the removal of organic matter. In the present study, the operation of two PN-AMX sequencing batch reactors with and without AS pre-treated OFMSW digestate (AS-SBR and nAS-SBR, respectively) was assessed. The specific anammox activity decreased by 90 % for increasing proportions of fed OFMSW in both cases, indicating no differences over the anammox activity whether the AS pre-treatment is implemented or not. For 100 % OFMSW proportion, the AS-SBR achieved better effluent quality than the nAS-SBR (127 +/- 88 vs. 1050 +/- 23 mg N/L) but with lower nitrogen removal rates (58 +/- 8 vs. 687 +/- 32 g N/(L.d)). Still, the latter required successive re-inoculations to obtain higher removal rates. Changes in the microbial communities were mainly correlated to sCOD/N ratios in the OFMSW, being Candidatus Brocadia the dominant anamnmox species. The results proved the AS to be a suitable pre-treatment, despite the higher sCOD/N ratios in the OFMSW digestate, achieving good synergy between the PN-AMX and heterotrophic denitrification processes.
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