Preliminary Research On The Ammonia-oxidization And The Phenomenon Of Aerobic Denitrification Of Chemoautotrophic Biofilm

Chemoautotrophic ammonia-oxidizing bacteria isolated from oil field formed a biofilm after enriched culture. The effects of six kinds of environmental factors such as pH, alkalinity, salinity, initial ammonium nitrogen concentration, temperature and partial pressure of oxygen on the chemoautotrophic biofilm's ability of ammonia-oxidization were studied. The data indicated that the ammonia-oxidization chemoautotrophic biofilm was notablely influenced by pH, alkalinity, ammonium nitrogen concentration, temperature and partial pressure of oxygen, and barely influenced by salinity. The analysis of ammonia-oxidization activity of the chemoautotrophic biofilm indicated that the optimum pH range was 7.5-7.7. In the environment containing NaCl of O%-3.5% concentration, the ammonia-oxidization chemoautotrophic biofilm showed certain salt-resist ability. In the environment containing initial ammonium nitrogen of 160-170mg/L and salinity of 1600-1700mg/L (the ratio of salinity and ammonium nitrogen was approximately 10:1), the ammonia-oxidization ratio was over 70%, and there was barely nitrite, the oxidized NH4+-N was partially transformed into nitrate. The chemoautotrophic biofilm had obvious turning points during the ammonia-oxidization. The ammonia oxidization was approximately 50% after 24h biotreatment and the products of ammonia-oxidization were mainly nitrite and nitrate below 36℃, while above 38℃, the rate was up to 95%, and the product was mainly nitrate, the concentration of...