Effects of Different Intermittent Aeration Strategies on the Start-up of SNAD Process

Abstract

In this experiment, two reactors, R1 and R2, were inoculated with anaerobic ammonium oxide sludge at room temperature (20℃±3℃). R1 employed intermittent constant aeration while R2 employed intermittent gradient aeration to start up the SNAD granular sludge process, to study the effects of different intermittent aeration ways. The results showed that the time for R2 to stabilize the performance in each stage was shorter, and the actual start-up speed was faster; after successful startup, the eigenvalues of R1 and R2 were 6.46 and 10.34, respectively. The suppression effect for NOB is better in R2; the DO fluctuation in a typical cycle was stable in R2 while the DO in R1 gradually rose overall and reached over 0.5mg·L-1 by the end of the cycle. R2 can maintain low DO more stably and inhibit NOB proliferation; after successful startup, the PN/PS values in the R1 and R2 reached 2.745 and 2.823, respectively, and the particle size reached 365.8 μm and 402.1 μm, respectively. The stability and sedimentation of the particles in R2 were stronger and the particle size increased faster.