Principle and engineering application of four dimention bio-reactor at nitrogen removal

The Four dimension bio-reactor at nitrogen removal (4DBNR) is consisted of series of the airlift alternant loop complex bio-filters(AALCF), with baffled flow along the longitudinal direction. Four dimension means three dimension flow controlled by the time changing aerobic operating. The aerobic and anaerobic circumstances formed along the liquid flux for nitrification/denitrification with intermittent circulation and liquid fully mixing in diffluent segments. Six months experiments on 4DBNR 60m³ in the volume for 20 m³/h sewage treatment at a holiday village indicated that the organic and nitrogenous contaminants were removed simultaneously. The average COD and NH₃-N loading were 2.11 and 0.24 kgd^-1.m³, the concentration in effluent was 29.7 and 6.6 mgL^-1 while COD 252 mgL NH₃-N 29.73 mgL^-1 in the influent, the average removal of COD and NH₃-N was 88% and 80.6% respectively, the average ratio of gas to liquid flow rate was 0.95. As a nitrogen removal process, not combined of many aerobic or anaerobic units, and no extra settling pole and reflux required, the advantages of 4DBNR on the compact structure and low operating cost are very obvious.