Do You Know the Nitrification Capacity of Your Plant? – A Simplified Testing Approach Can Help

For a wastewater activated sludge treatment plant with nutrient removal requirements, knowing and understanding its nitrification capacity is very important not only for facility designers to design or upgrade the facility, but also for facility operators to optimize the processes and achieve the maximum potential capacity of the plant. Maximum specific nitrifier growth rates are the key parameter for estimating plant nitrification capacity. A wide range of growth rates have been reported in various studies. Each facility has its own specific wastewater characteristics which makes it hard to pick one growth rate value to fit a plant's particular situation. In this paper, a simplified method was proposed for facilities to indirectly estimate the maximum specific nitrifier growth rate by measuring the overall nitrification rates through a series of simple tests using common laboratory equipment. The method has been used at two large wastewater treatment facilities in Indianapolis, IN. The testing results were reasonable and conservative compared to the data from the literature review. The obtained results using this proposed method were used to estimate required operating sludge retention time (SRT) and biomass inventory at various temperatures at the testing facilities, which greatly contributed to optimizing the plant operation and process performance.