Differential titrimeter for nitrification process control and energetic optimization in a large WRRF

Abstract

The objective of this study was to validate an innovative monitoring technique suitable for online control of nitrification rates for aeration control system and to use it to replace or integrate conventional batch tests for the estimation of nitrifying biomass kinetic parameters. For this purpose, a continuously-fed online differential titrimeter was designed and installed in a large industrial WRRF (Calice, Italy). The possibility to use the output of the titrimeter for the calibration of AOB (Ammonia Oxidation Bacteria) kinetic parameters was assessed by comparing the accuracy of the model using kinetic parameters calibrated on titrimeter output result and that of the model using kinetic parameters estimated on the results of conventional kinetic batch tests. The titrimeter is a robust tool to replace or integrate conventional batch tests for the estimation of nitrifying biomass kinetic parameters. Having validated the values obtained with the titrimeter, a new aeration control system was implemented full scale within Calice WRRF, which is no longer based on DO measurements and measurements of the effluent characteristics, but rather, on the values of the nitrification rate calculated continuously and in real time, thus allowing to adopt timely intervention measures in the case of malfunctioning of the process associated with changes in the plant operating conditions, eventual inhibition phenomena or other external factors.