Simultaneous oxidation of ammonium and p-cresol linked to nitrite reduction by denitrifying sludge

► Simultaneous oxidation of ammonium and p-cresol by denitrifying sludge using nitrite. ► Denitrifying sludge had metabolic capability for oxidizing p-cresol and ammonium. ► Reactor start-up for removing ammonium might be faster by using denitrifying sludge.