Starting characteristics of a reactor for simultaneous reduction of sulfate and oxidation of ammonium

Sulfate-dependent anaerobic ammonium oxidation is a novel biological reaction,in which ammonium is oxidized under anoxic conditions with sulfate as electron acceptors.The possibility and characteristics of simultaneous removal of ammonium and sulfate were investigated in a reactor for the sulfate-dependent anaerobic ammonium oxidation.The reactor was started up with the ANAMMOX sludge,which had high nitrogen removal by nitrite as electron acceptors.The results show that nitrite replaced by sulfate as the electron acceptors was practicable under ANAMMOX conditions.Simultaneous removal of ammonium and sulfate was observed and then the highest removal rate of ammonium and sulfate were up to 55.54 mg·L-1 and 53.15 mg·L-1(calculated by nitrogen and sulphur)at 300 day,respectively.The molar ratio of transformation between nitrogen and sulphur could be stabilized around 2.34.Moreover,pH was important for the reaction due to consumption of alkalinity.This may be a new way for the transformation of sulphur.