title: Minimizing N2O emissions and carbon footprint on a full-scale activated sludge sequencing batch reactor.
abstract: A continuous, on-line quantification of the nitrous oxide (N2O) emissions from a full-scale sequencing batch reactor (SBR) placed in a municipal wastewater treatment plant (WWTP) was performed in this study. In general, N2O emissions from the biological wastewater treatment system were 97.1 ± 6.9 g N2O-N/Kg [Formula: see text] consumed or 6.8% of the influent [Formula: see text] load. In the WWTP of this study, N2O emissions accounted for over 60% of the total carbon footprint of the facility, on average. Different cycle configurations were implemented in the SBR aiming at reaching acceptable effluent values. Each cycle configuration consisted of sequences of aerated and non-aerated phases of different time length being controlled by the ammonium set-point fixed. Cycles with long aerated phases showed the largest N2O emissions, with the consequent increase in carbon footprint. Cycle configurations with intermittent aeration (aerated phases up to 20-30 min followed by short anoxic phases) were proven to effectively reduce N2O emissions, without compromising nitrification performance or increasing electricity consumption. This is the first study in which a successful operational strategy for N2O mitigation is identified at full-scale.
authors.affiliation: Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Rodriguez-Caballero
authors.affiliation: Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Aymerich
authors.affiliation: Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain; REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Marques
authors.affiliation: Laboratory of Chemical and Environmental Engineering (LEQUIA-UdG), Institute of the Environment, University of Girona, Campus Montilivi s/n, E-17071 Girona, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Poch
authors.affiliation: Catalan Institute for Water Research (ICRA), Emili Grahit Street, 101, H(2)O Building, Scientific and Technological Park of the University of Girona, 17003 Girona, Spain. Electronic address: mpijuan@icra.cat.
authors.forename: M
authors.initials: M
authors.lastname: Pijuan
mesh_terms: D000393:Air Pollutants / Q000032:analysis; D000397:Air Pollution; D064751:Ammonium Compounds / Q000032:analysis; D019149:Bioreactors; D058572:Carbon Footprint; D009609:Nitrous Oxide / Q000032:analysis*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000191:economics / Q000379:methods*
chemical_list: D000393:Air Pollutants; D064751:Ammonium Compounds; D012722:Sewage; D009609:Nitrous Oxide
keywords: Carbon footprint; Domestic wastewater; Indirect CO(2) emissions; N(2)O emissions; Sequencing batch reactor