Investigation On Identification And Denitrification Characteration Of Aerobic Denitrifier In Lawn Soil

According to the Report on the State of Environment in China over the years, increasingly severe nitrogen pollution of water bodies does great harm to the natural environment and human health, in which nitrogen was present in the organic and inorganic forms.One of economic and effective approachs among numerous nitrogen removal processes was biodenitrification, yet which was confined in practice due to the complex process, the various nutriment and dissolved oxygen (DO) taken by corresponding bacterias in the diverse traditional nitrogen removal steps. The existence of aerobic denitrifier, proved by the domestic and international research in recent decades, made a breakthrough at the tradition denitrification theory, provided a new perspective to view the biodenitrification technology and application. Compared with the tradition anoxic denitrification, aerobic denitrification had became a hotspot of nitrogen removal from wastewater owing to its unique superiority.The aerobic denitrifier strain LD3with potassium nitrate as nitrogen source was isolated and screened from the campus lawn soil via limiting concentration, adding Chris reagents and diphenylamine and combined with plate streaking, and then expertized species identification, investigated denitrification ability and the effect of environment factors including carbon source, nitrogen source, DO, carbon nitrogen ratio (C/N), pH,temperature, etc. It was concluded that strain LD3was preliminarily identified to be pimelobacter, The removal rate of nitratenitrogen reached97.67%, the best denitrification time was5days, the optimum bacterium fluid does ratio was5%.Strain LD3lacked advantage of rich carbon and nitrogen sources except that high concentration nitrite was a disincentive. Strain LD3wasn’t strict with DO, which could meet the demands at1.8mg/L. The optimum initial C/N, pH and temperature was8,7.5and30℃respectively for aerobic denitrification. the best environmental factors determined by orthogonal test was as follows:rotate speed, initial C/N, initial pH, temperature was160r/min,10,7.5and30℃respectively. Experiemntal investigation on identification and denitrification characteration of strain LD3provided the theoretical reference for achieving nitrogen removal by aerobic denitrifier.