Effect of variations in flow rate and concentrations of influent on the nitrogen removal performance of the aerobic-anoxic-aerobic process

During a rain event municipal wastewater treatment plants experience a rapid change in the inflow conditions. The effect of the rapid change in a flow rate and/or concentrations on the nitrogen removal performance was studied by using results from the lab-scale experiment and simulation analysis. The mathematical model was developed for simulating the dynamic behavior of a biological nutrient removal system, and the validity of the model was confirmed with data from the experiment. Computed results and the experimental data showed that the net inflow of nitrogen compound through the reaction basin was controlled mainly by the flow rate and the reaction rate was subject to the loading rate in the transient state. The pulse-shaped perturbation with the low organic and nitrogen load resulted in the lesser performance of nitrogen removal than the perturbation with the increased load.