Modeling activated sludge population dynamics

Seyidoğlu, Aylin
Population dynamics play an important role in the performance of biological treatment by activated sludge. Current models often do not take this into consideration with concomitant failure in prediction of the outcome. Therefore this study aims at incorporating kinetics of population dynamics into ASM1 Activated Sludge Model. The AEROFIL model was used in the study for modeling population dynamics. The literature data was used for verification and model supporting. The already existing AEROFIL model was developed by using the AQUASEM utility program. Basic requirement of treatment by activated sludge is the floe mformation. Any failure in activated sludge floe formation results in decrease in treatment efficiency. The AEROFIL model used in this study is capable of predicting the behavior facultative aerobic floc-forming and obligate aerobic filamentous bacteria as well as nitrifying microorganisms in the case of aerobic bulking. This way it is now possible to predict activated sludge biocenoses, hence sludge settleability. Effects of high loadings with readily biodegradable substrate, flow pattern in longish aeration basins, inoculation by facultative aerobic floc-former microorganisms, inoculation by obligate aerobic filamentous microorganisms on the activated sludge biocenoses is investigated. Besides, effects of aerobic, anaerobic and anoxic selectors and selector compartmentalization on the filamentous microorganism to total biomass ratio were analyzed by using the AEROFIL model in AQUASIM program. The predictions were compared with the literature. Moreover, population dynamics in some of the biological nutrient removing activated sludge modifications like A/O, A2/0 and Bardenpho were investigated and compared to a completely mixed activated sludge process.
Citation Formats
A. Seyidoğlu, “Modeling activated sludge population dynamics,” M.S. - Master of Science, Middle East Technical University, 2003.