Belmonte, MarisolHsieh, Chia-FangCampos Gómez, José LuisGuerrero, LornaMéndez Pampín, Ramón JoséMosquera Corral, AnuskaVidal, Gladys2020-05-282020-05-282017Belmonte, M., Hsieh, C. F., Campos, J. L., Guerrero, L., Méndez, R., Mosquera-Corral, A., and Vidal, G. (2017). Effect of Free Ammonia, Free Nitrous Acid, and Alkalinity on the Partial Nitrification of Pretreated Pig Slurry, Using an Alternating Oxic/Anoxic SBR. BioMed research international, 2017. https://dx.doi.org/10.1155/2017/65716712314-6133http://hdl.handle.net/10347/22647The effect of free ammonia (NH3 or FA), free nitrous acid (HNO2 or FNA), and total alkalinity (TA) on the performance of a partial nitrification (PN) sequencing batch reactor (SBR) treating anaerobically pretreated pig slurry was studied. The SBR was operated under alternating oxic/anoxic (O/A) conditions and was fed during anoxic phases.This strategy allowed using organic matter to partially remove nitrite (NO2−) and nitrate (NO3−) generated during oxic phases.The desired NH4+ to NO2− ratio of 1.3 g N/g N was obtained when an Ammonium Loading Rate (ALR) of 0.09 g NH4+-N/L⋅d was applied. The system was operated at a solid retention time (SRT) of 15–20 d and dissolved oxygen (DO) levels higher than 3 mg O2/L during the whole operational period. PN mainly occurred caused by the inhibitory effect of FNA on nitrite oxidizing bacteria (NOB). Once HNO2 concentration was negligible,NH4+ was fully oxidized to NO3− in spite of the presence of FA. The use of biomass acclimated to ammonium as inoculum avoided a possible effect of FA on NOB activity.engCopyright © 2017 Marisol Belmonte et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly citedhttp://creativecommons.org/licenses/by/4.0/Free AmmoniaFree Nitrous AcidAlkalinityPartial NitrificationPretreated Pig SlurrySBRjournal article10.1155/2017/65716712314-6141open access