Lattergas som drivhusgas? Lattergas og den globale N kredsløb! Lattergas og biologisk spildevandsrensning: N fjærning!

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Mathilde Holst
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1 Udvidelser til AM processmodeller til at bestemme lattergas (N O) emission fra renseanlæg Barth F. mets Dansk Vand onference Nov. 1, 011 Contact info: oversigt Lattergas som drivhusgas? Lattergas og den globale N kredsløb! Lattergas og biologisk spildevandsrensning: N fjærning! Historisk perspektiv contra nyeste observationer! Hvordan beregnes IPCC spildevand s bidrag til N O dannelse Biologiske mekanismer af N O dannelse Ny modeller som kan beskrive N O dannelse alibrering af modeller onklusion 1

Lattergas og biologisk spildevandsrensning: N fjærning! Historisk perspektiv contra nyeste observationer!

2 N O emission increase due to anthropogenic activities Ca 10% of all GHG 75 ppb v (pre industrial) ppb v (005), often formed with N O, not a GHG, but tropospheric O 3 precursor N O, inert in troposphere, O 3 depletion in stratosphere N imbalances over the last 100 years: extra input of fixed N: 10 TgN/yr IPCC, 006 AA, 006 torste Globale Bidrag til N O udledinger: Biologiske ilder Agriculture (application of N fertilizer) Management of societal wastestreams (protein) Values: 16.4 TgN/yr total 11. TgN/yr derive from soils (60% natural-40% cultivated lands ) 6.9 TgN/yr anthropogenic (40%: agriculture, industry, combustion) 0. TgN/yr sewage treatment (1.3 to 3.%) But this accounts for upto 6% of total GHG emission of the water chain (CO, CH 4, N O) andsynligvis en ALVORLIG underestimering

Agriculture (application of N fertilizer) Management of societal wastestreams (protein) Values: 16.4 TgN/yr total 11. TgN/yr derive from soils (60% natural-40% cultivated lands ) 6.

3 Globale Biogeokemiske N redsløb 3-6. Heterotrophic Denitrification 8. Anaerobic Ammonium Oxidation 1. Nitrification tep 1. Ammonium Oxidation. Nitrification tep. Nitrite Oxidation Fuldskala rensningsanlæg Variabilitet af emissioner og fortrinsvis observeret i den aerobe zone (Ahn et al. 010) 3

1. Ammonium Oxidation. Nitrification tep.

4 Forhold som favoriserer N O udledningerne ummary by ampschreur et al. 009 Decreasing B competitiveness: Conditions that exacerbate N O emissions NH 4 + NH 3 Nitritation by Nitratation by B Denitration by DNB H s,o s,o 3 N ED Dinitritation by DNB Nitritation/anammox hortcut Nit/Denite Anammox NH + 4 N, 3 NH4 ph T 4

4 + NH 3 Nitritation by Nitratation by B Denitration by DNB H s,o s,o 3 N ED

5 Challenge! Generate a high NITRITE waste stream Move to partial nitritation will increase N O emission (Ahn et al, 011) Ca. 5%: ampschreur et al., 008, Desloover et al, 011 Message (Yang et al., 009) reduce nitrite buildup (step feed BR) In large part due to dynamic responses of, (Yu et al, 010) Message: dynamics-non steady state conditions exacerbate N O emissions Hvordan beregnes fra spildevand via IPCC reglerne? Uden spildevandsrensning - EF Med spildevandsrensning EF 3. g N O/population equivalent/year (derives from Czepiel et al., 1995, 11,000 pe A plant, 15 weekly grab samples) UA 7 g N O/population equivalent/year (for a BNR plant) % of the wastewater effluent N concentration 5

, 009) reduce nitrite buildup (step feed BR) In large part due to dynamic responses of, (Yu et al, 010) Message: dynamics-non steady state conditions exacerbate N O emissions

6 NH4 NHOH N X inetic rate expressions Mekanismer af N O dannelse Nitrifikation Nitrifikation Denitrifikation Ni et al. 011 Environ. cie. Technol. Udbred AM Process Model Process matrix pårorende N O dynamik i Process O N N N N N COD Y 1 1 Y Y Y 1 AMO HAO 1,, NH 4 NH 4 OH NH NH 4 X X HAO HAO I, O I, I, I, N N N OH NH NH OH X X Nye tilstandsvariabel :, NHOH, Nye processes Nye parameter Behov til parametervaerdier! Lignende process matrix parorende N O dynamik in HDNB 6

9 Y 1 1 Y Y Y 1 AMO HAO 1,, NH 4 NH 4 OH NH NH 4 X X 3-1 -3 4 4-1 - 3 HAO HAO I, O I, I, I, N N N OH NH NH OH X X Nye

7 Model alibrering: Blandet ultur (Aktiv lam) af - B-HDNB Case number Data source Yang et al. (009) Butler et al. (009) Itokawa et al. (001) im et al. (010) Reactor BR Batch Continuous Continuous Batch Process NITE and DENITE NITE DENITE NITE DENITE NITE Wastewat er domestic wastewater domestic wastewater domestic wastewater settled sewage Acetate and ammonium NH 4+ or NH OH Operation N O emission (% input N) Aerobic 7-13 % Aerobic 18 % Anoxic % Aerobic % Anoxic 0 % Aerobic 11-5 % ontrolleret input/forhold vedr. N, DO, COD Pilot eller lab forsøg Model evaluation applied to case study 1 (Yang et al, 009): (A) N O concentrations during nitritation; (B) NH 4+ -N, - -N and 3- -N profiles during nitritation; (C-D) nitrogen removal via nitrate in BR1; and (E-F) nitrogen removal via nitrite in BR. 7

and ammonium NH 4+ or NH OH Operation N O emission (% input N) Aerobic 7-13 % Aerobic 18 % Anoxic 0.1-0.5 % Aerobic 0.6-0.7 % Anoxic 0 % Aerobic 11-5 % ontrolleret input/forhold vedr.

8 Model evaluation applied to case study, 3, and 4 : (A-B) ammonium shock experiments with.8 (A) and.61 (B) mg NH 4+ -N (g ML) -1 ) by Butler et al. (009); (C-D) Low COD/N ratio condition by Itokawa et al. (001); and (E-F) NH 4+ (E) or NH OH (F) as substrate by im et al. (010). Best-fit værdier Best-fit parameters with 95% confidence intervals describing N O production in in four nitrification/denitrification case studies Parameter Definition Case 1 Case Case 3 Case 4 Ammonium oxidizing bacteria () AMO HAO 1, O IO, Maximum AMO-mediated reaction rate, h ± ± Maximum HAO-mediated reaction rate, h ± ± affinity constant for NH4 oxidation, g DO m ± ± ± substrate inhibition parameter, g DO m ± ± ± η Anoxic reduction factor for ± ± ± Heterotrophic bacteria (HB) H 3 BH H 3 O H 3 Maximum NoR-mediated reaction rate, h ± ± 0.07 inhibiting coefficient for NoR, g DO m ± ± affinity constant for NoR, g COD m -3.4 ± ±

Best-fit værdier Best-fit parameters with 95% confidence intervals describing N O production in in four nitrification/denitrification case studies Parameter Definition Case 1 Case Case 3 Case 4

9 Forudsige N O produktion under forskellige driftsforhold Predicted N O production in continuous reactors performing nitritation or heterotrophic denitrification. For nitritation, the initial conditions were: Reactor volume = L, volumetric flux = 0.5 L/h, and influent NH4 = 00 mg/l, with changing DO set points. For denitrification, the initial conditions for simulation were: Reactor volume = L, volumetric flux = 0.5 L/h, and influent 3 = 100 mg/l, with changing COD/N ratios. ammenfatning og perspektiver om N O N O-emissioner fra bioreaktorer, der behandler kvælstofrige affaldsstrømme, kan være betydelige Påvirke drivhusgassers fodaftryk af anlægget Forværres, hvis N fjernelse er et centralt mål Nitrifikation, ikke denitrifikation, er ofte årsagen Den udvidede AM-model er i stand til at beskrive de observerede tendenser Mere validering er påkrævet med forskellige typer af renseanlæg Undersøgelse på renseanlægniveau: graden, forekomst og reduktionsmuligheder for N O-udledninger Påvise hvordan rent autotrofe kvælstoffjernelsesprocesser påvirker N O udledninger Ni, B.-J., M. Ruscalleda, et al. (011). "Modeling Nitrous Oxide Production during Nitrogen Removal via Nitrification and Denitrification: Extensions to the General AM Models." Environmental cience & Technology 45:

For denitrification, the initial conditions for simulation were: Reactor volume = L, volumetric flux = 0.5 L/h, and influent 3 = 100 mg/l, with changing COD/N ratios.

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