Innovative start-up strategies for single-stage deammonification with conventional activated sludge: Results of a...

This study investigated innovative start-up strategies of a pilot-scale sequencing batch reactor (SBR) for single-stage deammonification using activated sludge as the sole inoculum source. In 24 m³ aerobic oxidizing bacteria cultivation plant, nitrogen loss efficiency was suggested to be an indicator for determining duration of cultivation. In 12 m³ ANAMMOX (ANaerobic AMMonium OXidation) cultivation plant, combined strategy (sequential fed-batch and continuous modes) was adopted to promote ANAMMOX activity from activated sludge. Both the cultivated sludge were inoculated in 24 m³ pilot-plant for single-stage SBR with deammonification. The feed distribution strategy was used to cultivate ANAMMOX bacteria selectively resulting in nitrogen removal rate of 0.73 kg/m³/d and nitrogen removal efficiency of 86.5 ± 1.9% within 254 days. Candidatus Brocadia sp. 40 was enriched from undetectable to 22.7% relative abundance. These findings indicated that fast start-up of the deammonification process was possible without ANAMMOX seed sludge in pilot-scale reactor with various variables.