A model for the simulation of the SHARON process:: pH as a key factor

The SHARON process allows partial nitrification of wastewaters with high ammonium content and, when coupled with the Anammox process, represents a more sustainable alternative for N-removal than a conventional nitrification-denitrification. In this work, a mathematical model describing a continuously aerated SHARON reactor is presented. Special attention was given to the pH, because it affects substrates availability and inhibition phenomena, implementing an algorithm for its calculation. Since ammonium-oxidizing and nitrite-oxidizing organisms are inhibited by their own substrates, ammonia and nitrous acid respectively, Haldane kinetics was used in both nitrification steps. A preliminary evaluation of the model using historical experimental data generated in a lab-scale SHARON reactor, fed with synthetic substrate, is also presented, corroborating that the quality of the obtained effluent is highly dependent on pH.