EVALUATION OF NUTRIENT REMOVAL PERFORMANCE FOR AN ORBAL PLANT USING THE ASM2d MODEL

Abstract

An Orbal plant achieving biological nutrient removal was modeled using nitrate, oxygen, ammoniumnitrogen and phosphate measurements for calibration. It was found that the oxygen and nitrate concentration in outer and middle ring is the bottleneck for modeling enhanced biological phosphorus removal (EBPR) whilst the system is under diurnal variation in the influent load. The simulation results showed that the overall system performances for total Kjeldahl-nitrogen and phosphate removal are around 77% and 94%, respectively. Also, the system is highly influenced by the operational changes rather than model kinetics. On the basis of this modeling exercise by using the ASM2d model, the necessary information for a trustable calibrated model that can be applied to upgrade the plant is discussed.