Kinetic models for nitrogen inhibition in ANAMMOX and nitrification process on deammonification system at room temperature

[Display omitted] •Andrews model describes NH3 inhibition for nitrification process.•Edwards model describes NH3 and NO2− inhibition for ANAMMOX process.•The inhibitory effect was more significant for NO2− than NH3 in the ANAMMOX process.•Monod model describes the absence inhibition for deammonification process.•Deammonification process was stronger for N-inhibition than nitrification and ANAMMOX. In this study were fitted the best kinetic model for nitrogen removal inhibition by ammonium and/or nitrite in three different nitrogen removal systems operated at 25°C: a nitrifying system (NF) containing only ammonia oxidizing bacteria (AOB), an ANAMMOX system (AMX) containing only ANAMMOX bacteria, and a deammonification system (DMX) containing both AOB and ANAMMOX bacteria. NF system showed inhibition by ammonium and was best described by Andrews model. The AMX system showed a strong inhibition by nitrite and Edwards model presented a best system representation. For DMX system, the increased substrate concentration (until 1060mgNH3-N/L) tested was not limiting for the ammonia consumption rate and the Monod model was the best model to describe this process. The AOB and ANAMMOX sludges combined in the DMX system displayed a better activity, substrate affinity and excellent substrate tolerance than in nitrifying and ANAMMOX process.