TY - JOUR
T1 - Comparison of methods for nitrous oxide emission estimation in full-scale activated sludge
AU - Myers, Shanna
AU - Mikola, Anna
AU - Blomberg, Kati
AU - Kuokkanen, Anna
AU - Rosso, Diego
N1 - Funding Information:
This research was financially supported by Helsinki Region Environmental Services Authority (HSY), Aalto University, and the Finnish Water Utilities Association (FIWA) development fund.
Publisher Copyright:
© 2021 The Authors Water Science & Technology |
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
PY - 2021/2/1
Y1 - 2021/2/1
N2 - Nitrous oxide (N2O) gas transfer was studied in a full-scale process to correlate liquid phase N2O concentrations with gas phase N2O emissions and compare methods of determining the volumetric mass transfer coefficient, K(L)a. Off-gas and liquid phase monitoring were conducted at the Viikinmaki wastewater treatment plant (WWTP) over a two-week period using a novel method for simultaneous measurement of dissolved and off-gas N2O and O-2 from the same location. K(L)a was calculated with three methods: empirically, based on aeration superficial velocity, from experimentally determined O-2 K(L)a, and using a static value of best fit. The findings of this study indicated trends in local emitted N2O consistently matched trends in local dissolved N2O, but the magnitude of N2O emissions could not be accurately estimated without correction. After applying a static correction factor, the O-2 method, using experimentally determined O-2 K(L)a, provided the best N2O emission estimation over the data collection period. N2O emissions estimated using the O-2 method had a root mean square error (RMSE) of 70.5 compared against measured concentrations ranging from 3 to 1,913 ppm and a maximum 28% error. The K(L)a value, and therefore the method of K(L)a determination, had a significant impact on estimated emissions.
AB - Nitrous oxide (N2O) gas transfer was studied in a full-scale process to correlate liquid phase N2O concentrations with gas phase N2O emissions and compare methods of determining the volumetric mass transfer coefficient, K(L)a. Off-gas and liquid phase monitoring were conducted at the Viikinmaki wastewater treatment plant (WWTP) over a two-week period using a novel method for simultaneous measurement of dissolved and off-gas N2O and O-2 from the same location. K(L)a was calculated with three methods: empirically, based on aeration superficial velocity, from experimentally determined O-2 K(L)a, and using a static value of best fit. The findings of this study indicated trends in local emitted N2O consistently matched trends in local dissolved N2O, but the magnitude of N2O emissions could not be accurately estimated without correction. After applying a static correction factor, the O-2 method, using experimentally determined O-2 K(L)a, provided the best N2O emission estimation over the data collection period. N2O emissions estimated using the O-2 method had a root mean square error (RMSE) of 70.5 compared against measured concentrations ranging from 3 to 1,913 ppm and a maximum 28% error. The K(L)a value, and therefore the method of K(L)a determination, had a significant impact on estimated emissions.
KW - Full-scale
KW - Gas transfer
KW - Greenhouse gases
KW - Nitrous oxide
KW - Off-gas
KW - Wastewater treatment
UR - http://www.scopus.com/inward/record.url?scp=85101585383&partnerID=8YFLogxK
U2 - 10.2166/wst.2021.033
DO - 10.2166/wst.2021.033
M3 - Article
C2 - 33600368
AN - SCOPUS:85101585383
VL - 83
SP - 641
EP - 651
JO - Water Science and Technology
JF - Water Science and Technology
SN - 0273-1223
IS - 3
ER -