Identification of Nitrification Kinetics for Activated Sludge Treating Leachate Using Combined Plant Start-up Data and Batch Kinetic Test

The study summarizes the necessary revisions for initiating the nitrification process in a full-scale leachate treatment plant that operates in a warm climate including dynamic simulation and kinetic characterization studies that were conducted to determine the nitrification kinetics. Following its commissioning, the process temperature in the plant reached high temperatures during the first six months of operation and failed to achieve complete nitrification. The process temperature was lowered from 40°C to 30°C with the aid of surface aerators installed in the anoxic volume of the bioreactor. With the selection of appropriate aerator capacity, besides reducing the temperature of the activated sludge, an 80% total nitrogen removal was achieved. Furthermore, as a result of dynamic simulation and kinetic studies, the maximum specific growth rates for ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) at a process temperature of 30°C were determined to be 0.85 day⁻¹ and 0.56 day⁻¹, respectively, around neutral pH.