Hybrid Nitrous Oxide Production from a Partial Nitrifying Bioreactor: Hydroxylamine Interactions with Nitrite.

The goal of this study was to elucidate the mechanisms of nitrous oxide (NO) production from a bioreactor for partial nitrification (PN). Ammonia-oxidizing bacteria (AOB) enriched from a sequencing batch reactor (SBR) were subjected to NO production pathway tests. The NO pathway test was initiated by supplying an inorganic medium to ensure an initial NH-N concentration of 160 mg-N/L, followed by NO (20 mg-N/L) and dual NHOH (each 17 mg-N/L) spikings to quantify isotopologs of gaseous NO (NO, NO, and NO).