Enhanced Nitrogen Removal using Immobilized Cell Augmented Activated Sludge Process

The immobilized cell augmented activated sludge (ICAAS) system combines a cell immobilization technique and an off-line enricher-reactor for the bioaugmentation of activated sludge system to improve treatment performances. In this study, enhanced nitrogen removal using ICAAS was investigated. Laboratory-scale, off-line, batch enricher-reactors were used to maintain nitrification and denitrification activities of coimmobilized nitrifiers and denitrifiers used to augment a laboratory-scale completely mixed activated sludge system (CMAS) treating synthetic wastewater. Cellulose triacetate was the media used to entrap nitrifiers and denitrifiers at a 2:1 mass ratio. ICAAS augmented with the coimmobilized cells between 5% and 20% by volume gained 24±5% higher nitrogen removal than a control CMAS, which provided nitrogen removal of 28±7%. The ICAAS scheme is a viable alternative for upgrading existing activated sludge systems to gain better nitrogen removal.