title: Enhanced ammonia removal at room temperature by pH controlled partial nitrification and subsequent anaerobic ammonium oxidation.
abstract: The Anammox-based processes are suitable for the treatment of wastewaters characterized by a low carbon to nitrogen (C/N) ratio. The application of the Anammox process requires the availability of an effluent with a NO2- -N/NH4+ -N ratio composition around 1 g g-1, which involves the necessity of a previous step where the partial nitrification is performed. In this step, the inhibition of the nitrite-oxidizing bacteria (NOB) is crucial. In the present work, a combined partial nitrification-ANaerobic AMmonia OXidation (Anammox) two-units system operated at room temperature (20 degreeC) has been tested for the nitrogen removal of pre-treated pig slurry. To achieve the successful partial nitrification and inhibit the NOB activity, different ammonium/inorganic carbon (NH4+/IC) ratios were assayed from 1.19 to 0.82g NH4+-Ng-1 HCO3-C. This procedure provoked a decrease of the pH value to 6.0 to regulate the inhibitory effect over ammonia-oxidizing bacteria caused by free ammonia. Simultaneously, the NOB experienced the inhibitory effect of free nitrous acid which avoided the presence of nitrate in the effluent. The NH4+/IC ratio which allowed the obtaining of the desired effluent composition (50% of both ammonium and nitrite) was 0.82 +/- 0.02 g NH4+-N g-1 HCO3- -C. The Anammox reactor was fed with the effluent of the partial nitrification unit containing a NO2 -N/NH4+ -N ratio of 1 g g-1' where a nitrogen loading rate of 0.1 g N L-1 d-1 was efficiently removed.
authors.affiliation: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Rua Lope Gomez de Marzoa s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: U
authors.initials: U
authors.lastname: Durán
authors.affiliation: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Rua Lope Gomez de Marzoa s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: A
authors.initials: A
authors.lastname: del Val Río
authors.affiliation: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Rua Lope Gomez de Marzoa s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: J L
authors.initials: JL
authors.lastname: Campos
authors.affiliation: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Rua Lope Gomez de Marzoa s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Mosquera-Corral
authors.affiliation: Department of Chemical Engineering, School of Engineering, University of Santiago de Compostela, Rua Lope Gomez de Marzoa s/n, E-15782 Santiago de Compostela, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Méndez
mesh_terms: D000641:Ammonia / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D064751:Ammonium Compounds / Q000737:chemistry / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000502:physiology*; D001673:Biodegradation, Environmental; D006863:Hydrogen-Ion Concentration; D058465:Nitrification / Q000502:physiology; D010084:Oxidation-Reduction; D013696:Temperature; D062065:Wastewater / Q000032:analysis / Q000737:chemistry; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
chemical_list: D000641:Ammonia; D064751:Ammonium Compounds; D062065:Wastewater; D014867:Water; D014874:Water Pollutants, Chemical