ONLINE NITRIFICATION MONITORING IN ACTIVATED-SLUDGE WITH A TITRIMETRIC SENSOR

Nitrification is an important part of activated sludge wastewater trea tment processes in view of the severe effluent discharge standards for nitrogen (N) that are nowadays imposed by legislation. Several on-lin e analyzers have been developed to achieve better monitoring and contr ol of biological N removal processes. In this paper, the results of on -line experiments on a pilot-scale activated sludge plant with a recen tly developed titrimetric sensor are described. Based on a titration o f an activated sludge sample, it was possible to estimate the ammonium N (NH4+-N) concentration in the activated sludge, without the need fo r any sample pretreatment. The NH4+-N concentrations obtained with the titration method were consistent with the NH4+-N concentrations measu red with an on-line analyzer, which was operated on the effluent of th e pilot plant. Contrary to chemical on-line NH4+-N analyzers, the titr ation method provides data about the nitrification rate of the activat ed sludge.