Performance comparison of two anammox reactors: SBR and UBF

The performance of two selected high rate anammox reactors, i.e. sequencing batch reactor (SBR) and an upflow biofilter (UBF) were compared operating them simultaneously at 30 °C. The sludge from anaerobic digester of a municipal wastewater treatment plant was used for inoculation and synthetic wastewater was fed to both reactors during the experiment. During start-up, the nitrogen loading rate (NLR) was increased gradually from an initial 140 to 560 mg/l day. The comparison of the performance revealed that the NLRs of SBR (2.7 g/l day) and UBF (2.5 g/l day) were far higher than those of the traditional nitrification/denitrification process. The biomass production of SBR outcompeted that of UBF. SBR took a longer time for start-up, i.e. about 57 days compared with 31 days of UBF. Moreover, SBR tolerated smaller pulse of substrate concentration and hydraulic load, showing a weaker stability compared with UBF.