Model-based evaluation of N2O recovery as an energy source in sulfur-driven NO-based autotrophic denitrification.

[Display omitted] • A SNAD model aimed to recover N 2 O from Fe(II)EDTA-NO was developed and evaluated. • Impacts of key operational conditions on N 2 O recovery were studied. • S/N mass ratio of ∼ 1.0 and high gas/liquid volumetric ratios favoured N 2 O recovery. • N 2 O recovery efficiency of up to 80.2%−84.9% was reached within 3.1 h–3.5 h. Instead of the conventional perception of nitrous oxide (N 2 O) as a potent greenhouse gas whose production should be minimized, this work aimed to assess N 2 O recovery as a potential energy source from nitric oxide (NO) in the form of Fe(II)EDTA-NO through element sulfur (S0) or thiosulfate (S 2 O 3 2−)-driven NO-based autotrophic denitrification (SNAD S0 or SNAD S2O3). A mathematical model was proposed to describe substrate dynamics related to N 2 O production and reduction and was successfully calibrated and validated using batch experimental data from lab-scale SNAD S0 and SNAD S2O3 systems under different substrates conditions. The model was subsequently employed to assess the potential of N 2 O accumulation and recovery by altering the S/N mass ratio and the ratio of gas volume to liquid volume of the system. The simulation results suggested that with a S/N mass ratio of nearly 1.0, high-purity N 2 O could be more rapidly and efficiently recovered from Fe(II)EDTA-NO in the SNAD S0 and SNAD S2O3 systems with a higher ratio of gas volume to liquid volume (i.e., a N 2 O recovery efficiency of up to 80.2%−84.9% reached within 3.1 h−3.5 h under the studied conditions). Comparatively, the SNAD S0 process showed an economic and viable advantage for practical applications to the efficient treatment and resource utilization of NO-containing flue gas. [ABSTRACT FROM AUTHOR]