Studies On Bacteria And Removal In Nitrification Process Of Nitric Oxide

Nitric oxide (NO) is a major source of atmospheric pollutant. Biofilter has become more concerned nowadays for NO removal.Lava and a new kind of material named Carbon Foam were applied as packing material in this experiment. The microbe from active sludge was cultured by sodium nitrite which is supplied as the only nitric source. After that the microbe were inoculated on the surface of packing material to develop the biofilm. The microbe was identified and separated. The potential and difference of the nitrification of the autotrophic biofilm on the three packing material were examined by the study in cone-shaped bottle and continuous and intermittent test in the biofilter. The main effects such as the character of packing material, temperature humidity, dissolved oxygen and organic carbon source were investigated respectively.The results show that (1) the bacteria in the biofilm were coccus and bacillus, which cooperated in nitrification process and restrain the denitrification in the removal process; (2) strain N-20 show the highest nitrification activity at the 25~30℃ pH 7.0-8.5. The removal efficiency get to 75.10% at 180 rpm in cradle within 1 week. Investigated the physiology, biochemical process and the growth of N-20, refered the Bergeys manual of Determiuntue Bacteriology (8th), it was inferred that it belongs to Nitrobacter sp.; (3) the upper segment of the packing material removed 38.7% of NO at EBRT 5 min. (4)A steady removal efficiency of 48%~74% was attained for the 24PPC carbon foam-based biofilter at specified NO inlet concentration of 61.5~123.0mg/m3 and EBRT of 4 minutes. (5) The perfect humidity of the biofilter is 31.5~32.9%(w/w). (6)Supplied with organic carbon source in the liquid phase with sufficient dissolved oxygen (DO≥2mg/L), the autotrophic microbe cooperate with heterotrophic microbe. But if the DO≤2mg/L , the growth of nitrobacteria were limited because the DO was exhausted by the heterotrophic microbe. Analyzed the balance of the nitrogen, it was suggest that denitrification was existed.