Suchergebnisse

This study aims at investigating the denitrification kinetics in two separate enriched cultures of denitrifying polyphosphate accumulating organisms (dPAO) and denitrifying glycogen accumulating organisms (dGAO) and compare their N2O accumulation potential under different conditions. Two sequencing batch reactors were inoculated to develop dPAO and dGAO enriched microbial communities separately. Seven batch tests with different combinations of electron acceptors (nitrate, nitrite and/or nitrous oxide) were carried out with the enriched biomass from both reactors. Results indicate that in almost all batch tests, N2O accumulated for both cultures, however dPAOs showed a higher denitrification capacity compared to dGAOs due to their higher nitrogen oxides reduction rates. Additionally, the effect of the simultaneous presence of several electron acceptors in the reduction rates of the different nitrogen oxides was also assessed in dPAOs and dGAOs ; This study was funded by the Spanish Government (MINECO) (CTM 2011-27163 and CTM 2015-66892-R), the European Commission (FP7-PEOPLE-2011-CIG 303946) and the Portuguese Fundação para a Ciência e Tecnologia (PTDC/AACAMB/12058/2010, UID/Multi/04378/2013 , PhD grant SFRH/BD/74515/2010). Spanish and Portuguese Governments are acknowledged for Acciones Integradas (PRIAIBPT- 2011-1232) and Luso-Espanhola action E-61/12. The European Commission is also acknowledged through COST action ES1202 (Water 2020). M. Pijuan and A. Ribera-Guardia acknowledge the Ramon y Cajal research fellowship (RYC-2009-04959) and the FPIPhD grant (BES-2012-052753) respectively provided by the Spanish Government

Denitrifying enhanced biological phosphorus removal (EBPR) systems can be an efficient means of removing phosphate (P) and nitrate (NO3−) with low carbon source and oxygen requirements. Tetrasphaera is one of the most abundant polyphosphate accumulating organisms present in EBPR systems, but their capacity to achieve denitrifying EBPR has not previously been determined. An enriched Tetrasphaera culture, comprising over 80% of the bacterial biovolume was obtained in this work. Despite the denitrification capacity of Tetrasphaera, this culture achieved only low levels of anoxic P-uptake. Batch tests with different combinations of NO3−, nitrite (NO2−) and nitrous oxide (N2O) revealed lower N2O accumulation by Tetrasphaera as compared to Accumulibacter and Competibacter when multiple electron acceptors were added. Electron competition was observed during the addition of multiple nitrogen electron acceptors species, where P uptake appeared to be slightly favoured over glycogen production in these situations. This study increases our understanding of the role of Tetrasphaera-related organisms in denitrifying EBPR systems ; The authors thank the Portuguese Fundação para a Ciência e Tecnologia (UID/Multi/04378/2013, AMB/120581/2010), UCIBIO (FCT/MEC UID/Multi/04378/2013, POCI-01-0145-FEDER-007728), the European Commission (Water JPI project 196 (WaterWorks2014 ERA-NET Co-funded Call): "Smart decentralized water management through a dynamic integration of technologies (Watintech)") and the Spanish Government through project CTM2015-66892-R for financing. Ricardo Marques acknowledges the PhD grant (SFRH/BD/74515/2010) provided by the Portuguese Fundação para a Ciência e Tecnologia. Spanish and Portuguese Governments are acknowledged for Acciones Integradas (PRI-AIBPT-2011-1232) and Luso-Espanhola action E-61/12. The European Commission is also acknowledged through COST action ES1202 (Water 2020). A. Ribera-Guardia acknowledge the FPIPhD grant (BES-2012-052753) provided by the Spanish Government