Abstract
Recently, nitrogen pollution is one of the biggest problems and novel nitrogen removal process, Anammox (anaerobic ammonium oxidation) is now regarded to be a promising alternative to the conventional nitrogen removal process. In Anammox reaction, ammonia is oxidized to nitrogen gas using nitrite as an electron donor. Recently, CANON process, in which nitrification to nitrite and anammox occur in one reactor, has been developed. Using anammox granules, new CANON reactor could be started up within 1 month and the anammox rate of the reactor was 56% of that of the seed granules. The reactor showed a stable nitrogen removal performance for 4 months. The average nitrogen removal rate of the reactor was observed to be 0.4 kgN/m3/d and the average nitrogen removal efficiency was 74%. There seems to be various factors affecting CANON process, in which nitrification in aerobic condition and anaerobic anammox reaction occur at the same time. Among them, DO concentration was proved to be the most important factor affecting nitrogen removal efficiency in CANON process.
