Denitrification Technology And Biofilm System Kinetics For Denitrifying Bacteria

In order to investigate the denitration performances of denitrifying bacteria in hightemperature, a series of research were performed, including the domestication,formation of biofilm on the packings, process parameters and influence factors forbioremovel of NOx. The main content is as follows:Denitrifying bacteria coming from the sewage pool was selected as the best one forthe subsequent experiments. The composition of culture medium was controlled tomake the best growth environment for bacteria, meanwhile the temperature wasincreased step by step. It was shown that bacteria after long time temperaturedomestication could be much stronger than one without domestication. The former wasfaster to adapt to the environment of high temperature, and more quickly into thelogarithmic growth stage. In the culture ammonium salt was the indispensable nitrogensource, which was good for the growth of bacteria.The biofilm was formed with the bacteria selected from the domesticationexperiment, and the glucose was added into the culture for better biofilm. In thebeginning, NOx concentration was increased with the decreasing of nitrate content,which was in order to make the bacteria tolerate NOx. It was shown that after long timedomestication, the denitrifying bacteria could perform the denitrification, and at0.06m3/h gas flow rate and0.12m3/h liquid flow rate the NOx removal efficiency wasthe best. FeII-EDTA was added into the culure for promoting NO solubility in thecondition of simultaneous bioremoval of SO2and NOx, and it was showen that0.2g/LFeII-EDTA was good for denitrification but0.4g/L FeII-EDTA was not. In the biofilter,an irreversible decomposition reaction of FeII-EDTA was conducted and FeS wasformed. Biofilm surface was covered with FeS and which impeded the contact of NOand biiofilm surface. Meanwhile the NO concentration in the culture was decreasedbecause of the lost of FeII-EDTA.Based on the experiments, the dynamics model for denitrification was obtainedusing the Monod kinetic equation and Two-film Theory model. The simultation resultswere in good agreenment with experimental values of the gas flow rate and specialsurface area of packings.