This study evaluated the eff ectiveness of thymol and sodium fl uoride (NaF) as biodegradation inhibitors (BIs) in mitigating

ammonia emissions from swine manure and their implications on anaerobic digestion (AD) for energy recovery processes.

The core fi ndings revealed that both thymol and NaF markedly lowered ammonia levels in swine manure during the 10 days

of storage with NaF showing superior effi cacy. The application of 50 mg of thymol/g volatile solids (VS) and 50 mg of

NaF/g VS resulted in ammonia reductions of 62.1% and 46.7%, respectively, compared to that in the control (15.9 ± 0.6 mg

NH 4

+ -N). The exploration of methane production highlighted that at concentrations up to 200 mg/L, neither thymol nor NaF

negatively infl uenced AD, highlighting a dose-dependent relationship between BIs concentration and AD performance. By

applying kinetic analysis, the inhibitory concentrations (IC) for thymol and NaF were determined to be IC 30 at 462.4 mg

thymol/L and 335.8 mg NaF/L, respectively. BIs also signifi cantly altered microbial diversity and its abundance, crucially

aff ecting methane production potential. This research indicated the importance of carefully managing residual levels of BIs

in swine manure to optimize the energy recovery process through AD, balancing the need for ammonia emission control

without compromising methane output.