Effect of Biological and Mass Transfer Parameter Uncertainty on N₂O Emission Estimates from WRRFs

Abstract

This research used the detailed activated sludge model (ASM) to investigate the effect of parameter uncertainty on nitrous oxide (N2O) emissions from biological wastewater treatment systems. Monte Carlo simulations accounted for uncertainty in the values of the microbial growth parameters and in the volumetric mass transfer coefficient for dissolved oxygen (kLaDO), and the results show that the detailed ASM predicted N2O emission of less than 4% (typically 1%) of the total influent <inline-graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="00580-ilm01.gif"/> loading. Uncertainties in kLaDO were further investigated in experiments, which showed that lower values of kLaDO generated higher soluble N2O levels. The detailed ASM likely requires revision to account for abiotic reactions and other factors that cause higher levels of N2O emission.

Long-term Assessment of N₂O Emission Factor in Full-scale Oxidation Ditch Reactor Considering Spatiotemporal Distribution

“…In previous studies, several pathways for N 2 O production have been suggested, including denitrification by heterotrophic bacteria and AOB [15,43], biological and chemical reactions derived from hydroxylamine [45], the abiotic reaction of hydroxylamine with free nitrous acid [46,47] and a hybrid reaction between hydroxylamine and NO 2 − [26,48,49]. Particularly, N 2 O production from AOB denitrification has been reported to be the main pathway when DO concentration is approximately 1.0 mg L −1 [15,43,50], which is this study's condition.…”

Gaseous Emissions from Wastewater Facilities

“…Song et al (2017) investigated the parameter uncertainty on N2O emissions from biological treatment of wastewater using the activated sludge model. Results from the Monte Carlo simulations which accounted for the uncertainty in microbial growth parameters and DO mass transfer coefficient for (kLaDO) showed that the predicted N2O emission was < 4% (as compared to 1%) of the total influent ammonia load Zhou et al (2017).…”