Nitrification Rate in Biological Processes

At least four reaction rate equations have been proposed to describe the process of nitrification. A more precise understanding of this reaction rate is needed to optimize the design of the process. The proposed equations which include the Monod, zero-order, first-order, and autocatalytic growth are reviewed. An experimental study is described which was designed to better understand the process reaction rate. The study involved a thin film biological reactor fed with a synthetic medium developed for the study of nitrification. This simple model was used to provide flexibility and control over such parameters as hydraulics, slime layer thickness, contact time, and wall growth problems. The rate determination was developed by varying both initial concentration and contact time. Results indicate that the reaction rate is zero-order between an initial ammonia nitrogen concentration of 2.5 mg/l - 673 mg/l.