Enrichment of Anammox Bacteria by a Sequencing Fed Biofilm Batch Reactor (SFBFBR)

A sequencing fed biofilm batch reactor (SFBFBR) seeded with returning activated sludge of a WWTP was started up to enrich Anammox (Anaerobic Ammonium Oxidation) bacteria and to investigate the nitrogen removal characterization of the Anammox biofilm system. Initially, the operation period was controlled at 3 days and the mineral medium (30 mg/l ammonium, 30 mg/l nitrite, about 2 L) was supplied continuously to SFBFBR in the first 68 hours. After 44 days’ cultivation, ammonium and nitrite concentration were decreased simultaneously without COD and DO, which means the anammox activity presented in the reactor. From t=55 days, in order to further enrich anammox bacteria, the substrate load began to increase by reducing the operation period from 3 days to 1 day and increasing the ammonium and nitrite concentrations. At the end of the experiment, the reactor was able to treat nitrogen loading rates up to 200±10 mg N/(L.d). The ammonium and nitrite reacted in the stoichiometrical of 1:1.135.