Selective nitrification and denitrification in fixed bed biofilm reactors

A fixed bed biofilm reactor filled with ceramic media were used to remove nitrogen by selective nitrification (ammonium to nitrite). The effects of experimental conditions (nitrogen load, dissolved oxygen, nitrite ratio, C/N ratio) on denitrification were investigated. The reactor showed more than 80% average T-N removal efficiencies at T-N loading in the range of $1.1{\sim}3.3$ kg $T-N/m^3{\cdot}d$ C/N at the C/N ratio of 1. T-N removal efficiencies increased as nitrite ratio.