N2O production in a single stage nitritation/anammox MBBR process

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350 091018 NH₄-N 35 091018NO₃-N 300 30 NH₄-N (mg/l) 250 200 150 100 50 NH₄-N in (mg/l) NH₄-N out (mg/l) NOx-N (mg/l) 25 20 15 10 5 NO₃-N in (mg/l) NO₃-N out (mg/l) 0 0 20 40 60 0 0 20 40 60 Time (min) Time (min) Figure D55. Figure D58. 70 091018 NOx-N 12 091018 NO₂-N NOx-N (mg/l) 60 50 40 30 20 10 NOx-N in (mg/l) NOx-N out (mg/l) NOx-N (mg/l) 10 8 6 4 2 NO₂-N in (mg/l) NO₂-N out (mg/l) 0 0 20 40 60 0 0 20 40 60 Time (min) Time (min) Figure D56. Figure D59. 091018 DO, NO₂-N biosensor (mg/l), DO, NO₂-N (mg/l) 12 10 8 6 4 2 0 0 20 40 60 NO₂-N biosensor (mg/l) DO (mg/l) NO₂-N out (mg/l) Time (min) Figure D57. 86
Appendix E Scientific Article N2O production in a single stage nitritation/anammox MBBR process. Sara Ekström Water and Environmental Engineering Department of Chemical Engineering, Lund University, Sweden. Abstract. The nitrous oxide (N 2O) production from a laboratory nitritation/anammox MBBR reactor was determined from N 2O measurements in the water phase with a Clark-type microsensor. The reactor was operated at intermittent and continuous aeration to evaluate which operation mode that gives the highest N 2O production. Different aeration rates were used during continuous operation to examine the influence of dissolve oxygen (DO) on N 2O emissions. Measurements of N 2O production during prolonged unaerated periods were performed to examine possible mechanisms of the N 2O production. The MBBR produces 6- 11% of removed inorganic nitrogen as N 2O during intermittent operation, whereas only 2-3% was produced during continuous operation at low oxygen concentrations. Higher inorganic nitrogen removal was achieved during continuous operation and better process performance is thought to be one explanation of lower N 2O emissions during continuous operations of the laboratory MBBR. Introduction Nitrous oxide, a greenhouse gas with a global warming potential 320 times stronger than that of CO2, is known to be produced during nitrification and denitrification processes used to remove nitrogen from wastewaters (Jacob, 1999). Variable temperature and loading rates of inorganic nitrogen compounds, low pH, alternating aerobic and anaerobic conditions together with growth rate and microbial composition are parameters that have great influence on N2O emissions from a wastewater treatment plant (Kampschreur et al., 2008). Wastewater treatment plants using biologic treatment processes for nutrient removal are producing excessive sludge giving rise to ammonium rich effluent from the anaerobic sludge digestion. This internal wastewater stream is recombined with the influent of the treatment plant and corresponds to 15-20% of the total nitrogen load of the wastewater treatment plant (Fux et al., 2003). In the early 1990s a new biological treatment process for nitrogen removal through anaerobic ammonium oxidation (anammox) with nitrite as electron acceptor was discovered by research teams in Holland, Germany and Switzerland (Mulder et al., 1995, Hippen et al., 1997, Siegrist et al., 1998). Total stoichiometry of the anammox process has been estimated by Strous et al., (1998): 1NH 1.32NO 0.066HCO 0.13H 1.02 N 0.26NO 0.066CH2O . N . 2.03 H O. Anammox has turned out to be suitable for treatment of reject waters and other problematic wastewaters with a low COD/N ratio and high ammonium concentrations. 87
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Water and Environmental Engineering
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Summary Wastewaters contain abundan
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Acknowledgements I would like to ex
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Table of content Chapter 1 ........
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Chapter 1 1. Introduction Nitrogen
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1.3 Objectives The aim with this ma
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Chapter 2 2. Background 2.1 Biologi
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are intermediates in the chemical r
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minimum concentration of 2 mg/l sho
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2.3 Biofilm reactors Biofilm reacto
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2.3.4 Moving bed reactor Another wa
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To enable efficient nutrient remova
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The Canon process is often implemen
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2.5.1 Nitrification as a source of
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Table 3. N 2O emission from differe
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The microsensor is connected to a p
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Chapter 3 3. Material and Methods 3
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3.3 Analytical methods Concentratio
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Figure 11. Calibration setup for mi
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Chapter 4 4. Results 4.1 Process pe
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10 8 DO concentration, pH & tempera
Page 47 and 48: concentration), while the maximum p
Page 49 and 50: of N2O during aeration was slightly
Page 51 and 52: Table 13. Average N 2O concentratio
Page 53 and 54: 12 NO₂-N (mg/l) 10 8 6 4 2 NO₂-
Page 55 and 56: Aeration 1.6 (l/min) with carriers
Page 57 and 58: % produced N₂O 12 10 8 6 4 2 Prod
Page 59 and 60: laboratory system might be underest
Page 63: 6. Conclusions The following conclu
Page 67 and 68: 8. References Abma W.R., Schultz C.
Page 69 and 70: Hippen A., Rosenwinkel K-H., Baumga
Page 71 and 72: Metcalf & Eddy I. (2003). Wastewate
Page 73: van Niftrik L.A., Fuerst J.A., Sinn
Page 79 and 80: Appendix B Calculations of N2O emis
Page 81 and 82: The rN value is calculated with the
Page 83 and 84: Appendix C Microsensor measurements
Page 85 and 86: 12 090927 Prolonged unaerated perio
Page 87: 12 091016 Continuously operation, D
Page 90 and 91: 350 090921 NH₄-N 350 090922 NH₄
Page 92 and 93: 300 090926 Prolonged unaerated peri
Page 94 and 95: 091010 NOx-N 091013 NOx-N NOx-N (mg
Page 96 and 97: 35 091015 NO₃-N 70 091016 NOx-N 3
Page 100 and 101: The bacteria performing the microbi
Page 102 and 103: Typical profiles of how N2O and DO
Page 104 and 105: 12 10 091014 Continously operation,
Page 106: Mulder A.V.A, Robertson L.A., Kuene
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N2O production in a single stage nitritation/anammox MBBR process

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