The nature of interaction between immobilized nitrification and denitrification bacteria

Abstract

In this work, we pursue the investigation of a nitrogen removal system, which utilizes coupled reaction of nitrification and denitrification in a mixed immobilized cell culture. A systematic comparison of the coupled nitrification-denitrification system with the nitrification process is performed and the interaction between the populations is discussed. The experiments have been performed in sequencing batch reactors loaded with alginate- or agarose-immobilized cells. Measurements of ammonium, nitrate, and nitrite concentrations have demonstrated that the nitrification rates are higher in the mixed-culture system than in the nitrification process. No build-up of nitrates or nitrites in the mixed-culture system have been observed.