System for startup of partial nitritation - ANAMMOX - denitrification (PNAD) reaction

Abstract

A partial nitritation-anaerobic ammonium oxidation (ANAMMOX)-denitrification (PNAD) process was activated to provide the basis and experience for engineering. A stirred up-flow reactor with surface continuous oxygen-limited aeration was used to realize partial nitritation by controlling the dissolved oxygen (DO) (0.4-0.5mg/l) of the reactor. In this study, an ASBR reactor was inoculated with ANAMMOX activated sludge with denitrification properties. After 98 days of activity recovery, the total nitrogen removal rate reached 90%. The reactor was run to the 194th day, with the total nitrogen removal efficiency reaching 95% after increasing influent nitrogen concentration on the 99th day, and the two reactors were combined in series. Up to the 212th day, the influent NH4+-N was 253.51mg / (l•d), and the effluent NH4+-N, NO2--N and NO3--N concentration were 1.67 mg / (l•d), 1.18 mg / (l•d) and 5.68mg / (l•d) respectively. In addition the activated sludge of two reactors was also identified by 16S rRNA.