Towards efficient heterotrophic recovery of N 2 O via Fe(II)EDTA-NO: A modeling study.

Efficient recovery of nitrous oxide (N ₂ O) through heterotrophic denitrification with the help of Fe(II)EDTA-NO as a chelating agent has been regarded as an ideal technology to treat nitric oxide (NO)-rich flue gas. In this study, an integrated NO-based biological denitrification model was developed to describe the sequential reduction of the NO fixed in Fe(II)EDTA-NO with organic carbon as the electron donor. With the inclusion of only the key pathways contributing to nitrogen transformation, the model was firstly developed and then calibrated/validated and evaluated using the data of batch tests mediated by the identified functional heterotrophic bacteria at various substrates concentrations and then used to explore the possibility of enhancing N ₂ O recovery by altering the substrates condition and reactor setup. The results demonstrated that the optimal COD/N ratio decreased consistently from 1.5 g-COD/g-N at the initial NO concentration of 40 g-N/m ³ to 1.0 g-COD/g-N at the initial NO concentration of 420 g-N/m ³ . Furthermore, sufficiently increasing the headspace volume of the reactor was considered an ideal strategy to obtain ideal N ₂ O production of 86.6 % under the studied conditions. The production of high-purity N ₂ O (98 %) confirmed the practical application potential of this integrated treatment technology to recover a valuable energy resource from NO-rich flue gas.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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