Start-up And Operation Of Anaerobic Ammonium Oxidation Reactors In ASBR

The nitrogen released by wastewater will break up the ecology balance in the water body,and severely threaten human health.Conventional biological nitrification/denitrfication process has some disadvantages,such as high oxygen use,need for external C,high cost for running.More researchers pay attention to novel biological N removal processes,which have lower cost and higher efficiency.Anaerobic ammonium oxidation(ANAMMOX)is a new process in which ammonium is oxidized with nitrite serving as the electron acceptor under anaerobic conditions,producing nitrogen gas.The process targets wastewater that contains much ammonium and little organic material, such as sludge digestor effluents and landfill leachate.In this study,3 similar anaerobic sequential batch reactors(ASBR)were operated inoculated with different sludge,and other 3 similar ASBR were operated under different pH conditions to optimize operation conditions.Inoculated with aerobic nitrification sludge,denitrification sludge and anaerobic digested sludge,anaerobic ammonia oxidation reactors were started-up in three sets of ASBR.After 176d,170d and 137d's operation respectively,anaerobic ammonia oxidation processes were obtained successfully in these three reactors.At the steady phase of operations,the volumetric TN loadings were 0.15 kgN·m^-3·d^-1,0.11 kgN·m^-3·d^-1and 0.075 kgN·m^-3·d^-1,and the average removal efficiencies of TN were 84.81%,82.91% and 77.94%,respectively.ANAMMOX reactor inoculated with aerobic nitrification sludge set up more rapidly than that for other kinds of sludge,and TN removal efficiency were better.Inoculated with aerobic nitrification sludge,three sets of ASBR were start-up under different pH.After 176d,168d and 148d's operation respectively,anaerobic ammonia oxidation process were obtained successfully in these three reactors.ANAMMOX reactor operated under 7.9-8.2,higher pH consideration,set up more rapidly and TN removal efficiency were better. ANAMMOX reactor operated under 7.2-7.5,lower pH consideration,also have good efficiency of NH₄⁺-N and NO₂^--N removal,but the concentration of NO₃^--N increased is too high.