ALTERNATING AEROBIC-ANOXIC PROCESS FOR NITROGEN REMOVAL - DYNAMIC MODELING

A dynamic mathematical model was developed for the alternating aerobic -anoxic (AAA) completely mixed activated sludge process for the remova l of carbonaceous substrate, nitrification, and denitrification. The m odel is constructed on the Activated Sludge Model No. 1 (ASM 1) of the International Association on Water Pollution Research Control with so me revisions including pH and alkalinity. Experimental data obtained f rom a bench-scale AAA reactor under different operational conditions w ere used for parameter estimation and model validation. Model paramete rs were found to agree well with those used by the ASM1. Process perfo rmance at steady-state and dynamic conditions can be well predicted by the AAA model. Because nitrite is not treated as a state variable in the ASM 1, a modified model incorporating nitrite as a state variable has been developed to account for nitrite accumulation.