Abstract
The Anammox system was started up with 2L of activated sludge and 3L of anaerobic digestion sludge in a UASB reactor. After 140 days enrichment, the Anammox system was successfully started up. The ammonium removal efficiency reached to near 99.5%. HRT was shortened from 24h to 3h step by step to increase the NLR to 1.68g/L/d. During the steady state, the NRR reached to 1.46g/L/d, and the consumption ratio of NH4+ to N02- was in the range of 1.0~1.1. Substrate concentration shock was also investigated in the experiment. In the continuous experiment, when the concentration of FA and FNA was higher than 20mg/L and 7μg/L, the Anammox system was 60% inhibited. In batch experiment, the inhibitory threshold concentration of FA and FNA was 78mg/L and 30μg/L which was higher than that observed in continuous experiment. The results indicated that the recovered Anammox sludge has stronger resistance for high substrate concentration.
