title: The impact of aeration on the competition between polyphosphate accumulating organisms and glycogen accumulating organisms.
abstract: In wastewater treatment plants (WWTPs), aeration is the major energetic cost, thus its minimisation will improve the cost-effectiveness of the process. This study shows that both the dissolved oxygen (DO) concentration and aerobic hydraulic retention time (HRT) affect the competition between polyphosphate accumulating organisms (PAOs) and glycogen accumulating organisms (GAOs). At low DO levels, Accumulibacter PAOs were shown to have an advantage over Competibacter GAOs, as PAOs had a higher oxygen affinity and thus largely maintained their aerobic activity at low DO levels, while GAO activity decreased. Bioreactor operation at low DO levels was found to increase the PAO fraction of the sludge. Furthermore, an increase in aerobic HRT (at a DO level of 2 mg O2/L), promoted the proliferation of GAOs over PAOs, decreasing the EBPR efficiency. Overall, this study shows that low aeration can be beneficial for EBPR performance through selecting for PAOs over GAOs, which should be incorporated into WWTP models in order to minimise energetic costs and improve WWTP sustainability.
authors.affiliation: Requimte/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. Electronic address: mic16141@campus.fct.unl.pt.
authors.forename: Mónica
authors.initials: M
authors.lastname: Carvalheira
authors.affiliation: Requimte/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. Electronic address: a.oehmen@fct.unl.pt.
authors.forename: Adrian
authors.initials: A
authors.lastname: Oehmen
authors.affiliation: Requimte/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal; Instituto de Biologia Experimental e Tecnológica (IBET), Av. da República (EAN), 2784-505 Oeiras, Portugal. Electronic address: gs.carvalho@fct.unl.pt.
authors.forename: Gilda
authors.initials: G
authors.lastname: Carvalho
authors.affiliation: Requimte/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. Electronic address: eusebio@fct.unl.pt.
authors.forename: Mário
authors.initials: M
authors.lastname: Eusébio
authors.affiliation: Requimte/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Campus de Caparica, 2829-516 Caparica, Portugal. Electronic address: amr@fct.unl.pt.
authors.forename: Maria A M
authors.initials: MAM
authors.lastname: Reis
mesh_terms: D000332:Aerobiosis; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry; D006003:Glycogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D010758:Phosphorus; D011122:Polyphosphates / Q000737:chemistry*; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D002244:Carbon; D006003:Glycogen; D010100:Oxygen; D010758:Phosphorus; D011122:Polyphosphates; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Aeration energy; Dissolved oxygen (DO); Enhanced biological phosphorus removal (EBPR); Glycogen accumulating organisms (GAOs); Microbial competition; Polyphosphate accumulating organisms (PAOs)