Design and Operation Optimization to Minimize the Production of Nitrous Oxide in Nitrification-Denitrification Activated Sludge Systems

Fundamental process simulation and empirical analysis methods are combined to optimize denitrification system design and operational controls to minimize emissions of nitrous oxide (N2O), an important greenhouse gas. These N2O emissions can be highly variable, particularly under the dynamic loading conditions found at many municipal and industrial facilities. ASMN is a fundamental model which incorporates nitric oxide (NO) and N2O as denitrification intermediate products and is able to reproduce laboratory and field measurements that link N2O emissions to specific process conditions including COD/N ratios.Full factorial design-of-experiment (DOE) simulations were used to evaluate a specific MLE process configuration and influent dataset. Under the conditions evaluated, the substrate half saturation coefficient for N2O reduction to nitrogen gas is the most important parameter. The internal recirculation rate (IRC) is the most important process variable contributing to N2O emissions.