Determination of the nitrification kinetic parameters of sludges using a new titration bioassay system: MARTINA

A new titration system named MARTINA (Multiple Analyte Reprogrammable TItratioN Analyser) developed by Politecnico di Milano, which combines a pH -stat titration unit with a DO-stat titration unit has been used to estimate kinetic parameters of sludge samples taken from two Italian wastewater treatment plants (municipal and industrial). The nitrification kinetic parameters were estimated on nitrogen profiles obtained experimentally by means of the minimum square error criteria. By comparing ammonium oxidisers kinetic parameters determined by the two set-point titrations, differences lower than https://www.w3.org/1998/Math/MathML" display="inline"> 12 % were obtained, indicating a good correspondence between the two methods. Kinetic parameters of nitrite oxidisers could be obtained only by DO-stat titration. Results showed a good repeatability as indicated by a coefficient of variation (CV) lower than https://www.w3.org/1998/Math/MathML" display="inline"> 30 % for maximum reaction rate estimation. MARTINA makes it possible to estimate kinetic parameters of ammonium and nitrite oxidisers bacteria, demonstrating that by combining the two set point titrations a complete characterisation of the nitrification biomass is easily achieved.