Design and development of a soft-sensor for ammonia degradation and nitrite accumulation in an activated sludge reactor

A soft-sensor for on-line estimation of ammonia degradation (alpha) and nitrite accumulation (beta) is proposed in this paper. The soft-sensor has showed a good behavior in the following of trends and has got final values very close to the experimental analysis. Thought this soft-sensor was not conceived for replacing the laboratory analysis, gives alpha and beta estimations for all the instants in between the laboratory sample taking. The data resulting from the laboratory analysis is used to update the model parameters on which the soft-sensor is based on. Furthermore, the model is used to feed an on-line optimization system to look for the pH and O₂ set-points whose gives maximum ammonia degradation (alpha) and nitrite accumulation (beta). This optimization system is executed every time that the model parameters are updated