Review: Modeling of nitrogen removal and control strategy in continuous-flow-intermittent-aeration process
The continuous-flow-intermittent-aeration process was introduced to achieve nitrogen removal in a wastewater treatment plant (WWTP). Without structural readjustment of completed mixed activated-sludge treatment unit, operation scheme of intermittent aeration would be upgraded to promote the WWTP performance. As an aid of the implementation, mathematical simulation models were developed as an invaluable tool. Due to some uncertainties associated with the mechanisms and quantification of the process, some simplification in a reliable model should be addressed progressively by using the relevant information drawn from the existing models, the literature and the works on the experiments. An unsteady-state model for the upgrade of WWTP process was developed. The model predictions are coincident with the practical trends of the effluents, which the error percentages are about 10%. Moreover, the model facilitates the insight into nitrogen removal with the process operational conditions. The study could provide some valuable reference and recommendation on the design and operation of the municipal WWTP.
Key words: Kinetic model, nitrification, denitrification, process control, continuous flow, intermittent aeration.