Systematic calibration of N2O emissions from a full-scale WWTP including a tracer test and a global sensitivity approach

Nitrous oxide (N2O) is a greenhouse gas (GHG) emitted during biological nitrogen removal from wastewater treatment plants (WWTPs). Some modelling tools have been proposed to predict N2O emissions the design and operation of WWTPs. In this study, novel ASM2d-N2O model, which accounts for production in nutrient WWTPs, was used study associated full-scale WWTP with two independent lines. Firstly, hydraulics characterized by residence time distribution test, showing flow equally divided into lines (49.3 vs. 50.7%), that each reactor worked as an ideal continuous stirred tank secondary settler model flux similar plug-flow reactor. The then calibrated using experimental data obtained under dynamic conditions. A global sensitivity analysis select, among 59 parameters, five candidates resulted be related nitrifying organisms. Different parameter subsets up four parameters were evaluated, being subset [µNOB, qAOB_AMO, KO2_NOB, KNO2_NOB] best, achieving 53.3% reduction calibration cost function. fit provided reasonably description nutrients emission trends, considering inherent operational variability suffered Finally, simulation-based showed that, given conditions, unbalanced flow-rate between did not result significant increase on emissions. results show can suitable tool predicting therefore find conditions help minimise these