Abstract
Anammox, anaerobic ammonium oxidation with nitrite, is recognized as a unique and novel nitrogen metabolic pathway for ammonia-rich wastewater treatment compared with conventional nitrification and denitrification system mainly due to cost saving. However, the enrichment culture of marine anammox bacteria (MAB) and its potential nitrogen removal capacity, so far, have not been well studied. The present study described the effects of shortening hydraulic retention time (HRT) and increasing nitrogen concentration in a medium on the nitrogen removal performance in the MAB culture using upflow column bioreactors in which non-woven fabric was installed as biomass carrier and the change of the nitrogen removal performance was continuously monitored. The results showed that in reactor-I, nitrogen removal rate (NRR) of 1.1 kg-N/m3/d was attained as a maximum value when the nitrogen loading rate (NLR) was 1.3 kg-N/m3/d at 740 mg-N/L total influent nitrogen concentration and 18 h HRT. As for reactor-II, a maximum NRR of 6.33 kg-N/m3/d was attained when the NLR was 10.08 kg-N/m3/d at 210 mg-N/L total influent nitrogen concentration and 0.5 h HRT. These results indicate that shortening HRT is an easy way to achieve high-rate nitrogen removal performance in the MAB culture.
