Operation of a SHARON nitritation reactor: practical implications from a theoretical study

This contribution deals with the behaviour of a SHARON reactor for nitrogen removal from wastewater streams with high ammonium concentrations. A system analysis is performed on a two-step nitrification model, describing the behaviour of such a reactor. Steady states are identified through direct calculation using a canonical state space model representation. Practical operation of a SHARON reactor aims at reaching ammonium conversion to nitrite only (nitritation), while suppressing further conversion to nitrate. It is shown how this desired behaviour can be obtained by setting the dilution rate dependent on the influent ammonium concentration. The impact of microbial growth characteristics on the suitable operating region is examined, as well as the effect of reactor temperature and pH. Advice is given for robust reactor design and operation.