Modeling of an immobilized sludge reactor with polyethylene glycol (PEG)-pellet to remove NH₄-N from groundwater Available to Purchase

An immobilized sludge system model was developed to simulate nitrification (NH₄-N → NO₃-N) and denitrification (NO₃-N → N₂) processes in a PEG-pellet (microorganisms entrapped in polyethylene glycol (PEG)) reactor for removing NH₄-N from groundwater. The nitrification and denitrification processes were described by modifying the Michaelis-Menten kinetic incorporating the factors of dissolved oxygen, organic carbon and pH. The model consists of seven fixed parameters out of which the maximum velocity of nitrification (V_m,ni) was found to be the most sensitive. The model can be applied to predict the best operating condition (i.e., duration of intermittent aeration period and pellet ratio (PEG-pellet in reactor/reactor volume)) for different NH₄-N concentrations. The model predicts that the highest efficiency to remove 45 mg/L of NH₄-N can be achieved when the PEG-pellet reactor with 0.2 pellet ratio is operated under 6 h of intermittent aerations and the efficiency is strongly affected by the pellet ratio, especially when NH₄-N concentration in the influent is higher than 60 mg/L.