Distinctive denitrifying capabilities leads to different N 2 O - PowerPoint PPT Presentation

Distinctive denitrifying capabilities leads to different N 2 O production in dPAO and dGAO cultures Anna Ribera-Guardia 1 , R. Marques 2 , C. Arangio 1 , M. Carvalheira 2 , A. Oehmen 2 , M. Pijuan 1 aribera@icra.cat 16th September 2016

N2O during denitrification NaR NiR Nor Nos Biomass - NO 2 - N 2 O NO 3 NO N 2 growth - - rNO 3 rNO 2 rNO rN 2 O e- e- e- e- e- competition?? C-source ATP ATP PAO GAO Slower e- supply PHA EBPR ATP ATP - - NO 3 NO 3 3- PO 4 communities PO 4 - P PHA PHA N 2 ? N 2 ? Glycoge Poly- n P 16th September 2016

Objectives  Explore the denitrification kinetics of two different dPAO and dGAO cultures  Study the N 2 O accumulation potential of both cultures  Assess the occurrence of electron competition 16th September 2016

Materials and Methods: Bioreactors operation 2 different SBR for dPAO and dGAO  cultures, respectively Argon Cycle: 6 hours  O 2 pH Air  Anaerobic phase (1h 45 min) HCl 0.1 M  Anoxic phase (2h) Phosphate Nitrogen  Aerobic phase (1h 30 min) media media Carbon Waste  Settling /decant phase/Idle (45 min) media activated sludge Carbon source: Propionic and acetic  dPAO V = 2 L acids dGAO V = 6 L SRT: 10 days  pH : 7.5  0.1  16th September 2016

Materials and Methods: Batch tests  Sludge withdrawn from the end of the anaerobic phase of each reactor  330 mL sealed reactor  anoxic conditions  pH controlled at 7.5  Dissolved N2O online monitored by an N2O microsensor Temperature probe Batch test A B C D E F G N2O reservoir microsensor type pH probe NO 3 NO 2 N 2 O NO 3 NO 2 NO 3 NO 3 - - - - - - Electron acceptors N 2 O N 2 O NO 2 - NO 2 - used N 2 O

Results:SBRs operation Acetate Propionate NO2- NO3- PO43- Feed P and C Feed N dPAO Acetate, Propionate (mg COD/L); PO43- (mg P/L) Anaerobic Anoxic Aerobic 140 35 a 120 30 3- NO3-, NO2- (mg N/L) 100 25 80 20 60 15 40 10 20 5 0 0 0 100 200 300 Time (min) 16th September 2016

Results:SBRs operation Acetate Propionate NO2- NO3- PO43- Feed P Feed P and C Feed N and C dPAO dGAO Feed N Acetate, Propionate (mg COD/L); PO43- (mg P/L) Acetate, Propionate (mg COD/L); PO43- (mg P/L) Anaerobic Aerobic Anoxic Aerobic Anaerobic Anoxic 140 35 140 35 a b 120 30 120 30 NO3-, NO2- (mg N/L) NO3-, NO2- (mg N/L) 100 25 100 25 80 20 80 20 60 15 60 15 40 10 40 10 20 5 20 5 0 0 0 0 0 100 200 300 0 100 200 300 Time (min) Time (min) 16th September 2016

Results:Microbial community FISH PROBES Relative abundance dPAO-SBR 26.03 ± 4.75 % PAO I 15.42 ± 2.82 % PAO II 42.40 ± 8.32 % PAOMIX 22.93 ± 4.41 % GAOMIX DFImix, DFIImix and DFIII 4.17 ± 0.16 % dGAO-SBR 55.60 ± 1.86 % GAOMIX 6.33 ± 0.24 % DFImix, DFIII and DFIV 13.20 ± 0.88 % DFIImix 14.30 ± 1.52 % PAOMIX 16th September 2016

Results:single electron acceptor NO2- NO3- N2O 35 0.5 dPAOs A NO3- , NO2- (mg N/g VSS) 30 0.4 N2O (mg N/g VSS) 25 0.3 20 15 0.2 10 0.1 5 0 0.0 0 10 20 30 40 Time (min) 35 0.5 A dGAOs NO3-, NO2- (mg N/g VSS) 30 0.4 N2O (mg N/g VSS) 25 0.3 20 15 0.2 10 0.1 5 0 0.0 0 10 20 30 40 Time(min)  N2O accumulates for both cultures  Nitrite accumulates for dGAOs 16th September 2016

Results:single electron acceptor NO2- NO3- N2O 35 0.5 35 6 dPAOs B dPAOs A NO3- , NO2- (mg N/g VSS) 30 30 5 0.4 N2O (mg N/g VSS) NO2- (mg N/g VSS) N2O (mg N/g VSS) 25 25 4 0.3 20 20 3 15 15 0.2 2 10 10 0.1 5 5 1 0 0 0.0 0 0 10 20 30 40 0 10 20 30 40 Time (min) Time (min) 35 0.5 35 6 A dGAOs B dGAOs NO3-, NO2- (mg N/g VSS) 30 30 5 0.4 NO2- (mg N/g VSS) N2O (mg N/g VSS) N2O (mg N/g VSS) 25 25 4 0.3 20 20 3 15 15 0.2 2 10 10 0.1 5 5 1 0 0 0.0 0 0 10 20 30 40 0 10 20 30 40 Time(min) Time(min)  dPAOs prefer nitrite over nitrate  dGAOs prefer to consume nitrate  NO2- inhibits N 2 O reduction in dGAOs 16th September 2016

Results:single electron acceptor NO2- NO3- N2O 35 0.5 35 6 35 dPAOs B dPAOs dPAOs A C NO3- , NO2- (mg N/g VSS) 30 30 30 N20 (mg N/g VSS) 5 0.4 N2O (mg N/g VSS) NO2- (mg N/g VSS) N2O (mg N/g VSS) 25 25 25 4 0.3 20 20 20 3 15 15 15 0.2 2 10 10 10 0.1 5 5 5 1 0 0 0 0.0 0 0 10 20 30 40 0 10 20 30 40 0 10 20 30 40 Time (min) Time (min) Time (min) 35 0.5 35 6 35 A dGAOs B dGAOs dGAOs C NO3-, NO2- (mg N/g VSS) 30 30 30 5 0.4 NO2- (mg N/g VSS) N2O (mg N/g VSS) N2O (mg N/g VSS) N2O (mg N/g VSS) 25 25 25 4 0.3 20 20 20 3 15 15 15 0.2 2 10 10 10 0.1 5 5 5 1 0 0 0 0.0 0 0 10 20 30 40 0 10 20 30 40 0 10 20 30 40 Time(min) Time(min) Time (min)  dPAOs consume N 2 O faster than dGAOs 16th September 2016

Results: multiple e- acceptors dPAOs dGAOs 35 35 NO3- NO3- 30 30 NOx red rates (mg N/gVSS·h) NOx red rates (mg N/gVSS·h) NO2- NO2- 25 25 N2O N2O 20 20 15 15 10 10 5 5 0 0 A B C D E F G A B C D E F G Tests Tests 16th September 2016

Results: multiple e- acceptors dPAOs dGAOs 35 35 NO3- NO3- 30 30 NOx red rates (mg N/gVSS·h) NOx red rates (mg N/gVSS·h) NO2- NO2- 25 25 N2O N2O 20 20 15 15 10 10 5 5 0 0 A B C D E F G A B C D E F G Tests Tests  dPAOs have higher denitrifying capacity  Nitrate reduction rates in dPAOs are constant in all tests  dGAOs presented higher N 2 O accumulated/N-reduced 16th September 2016

Results: electron competition dPAOs Electron consumption rate (mmole/gVSSh dGAO Electron consumption rate (mmole/gVSSh 9 9 Nar Nar 8 Nir 8 Nir Nor Nor 7 7 Nos Nos 6 6 5 5 4 4 3 3 2 2 1 1 0 0 A B C D E F G A B C D E F G Tests Tests No electron competition   Higher e- consumption rates in dPAOS  higher reduction rates 16th September 2016

Conclusions  N 2 O accumulation was higher in dGAOs than in dPAOs and intensified when nitrite was present  No electron competition was detected  dPAOs have higher denitrifying capacity than dGAOs 16th September 2016

Acknowledgements Project CTM 2011-27163 and CTM 2015-66892-R Ramon y Cajal RYC-2009-04959 PhD grant BES-2012-052753 Acciones IntegradasPRI-AIBPT-2011-1232) Luso-Espanhola action E-61/12 PTDC/AAC-AMB/12058/2010, UID/Multi/04378/2013 , PhD grant SFRH/BD/74515/2010 COST action ES1202 (Water 2020)

16th September 2016

Distinctive denitrifying capabilities leads to different N 2 O production in dPAO and dGAO cultures Anna Ribera-Guardia 1 , R. Marques 2 , C. Arangio 1 , M. Carvalheira 2 , A. Oehmen 2 , M. Pijuan 1 aribera@icra.cat Thank you very much for your attention 16th September 2016