Is the ammonia stripping pre-treatment suitable for the nitrogen removal via partial nitritation-anammox of OFMSW digestate?

•One-stage PN-AMX process treated OFMSW digestate with previous ammonia stripping.•At long-term operation OFMSW provoked 90 % reduction of specific anammox activity.•A shift between anammox and denitrifying bacteria occurred over 1.7 g sCOD/g N.•N removal of 94 % with a rate of 58 mg N/(L·d) treating OFMSW with ammonia stripping.•Heterotrophic denitrification contributed to the N removal up to 39 %.