The Study Of Denitrification In Hybrid Biological Reactor

During treating artifical wastewater in Hybrid Biological Reactor,various influencing factors for denitrification of biological nitrogen removal were studied.There existed a lot of suspended and adhesive microorganwasms of higher activity in Hybrid Biological Reactor through Inoculation, Biofilm culturing and domestication.By controlling the loading of organic carbon and nitrate nitrogen and adjusting temperature and DO concentration,we studied the influence of different C/N,DO and substrate concentration on nitrate nitrogen removal rate and COD removal rate,while analyzed the relation of pH and removal amount of nitrate nitrogen, and anti-shock loading capability of Hybrid Biological Reactor,ect.The main conclusions were as follows:1.Denitrification was performed in Hybrid Biological Reactor under the conditions of that pH was between 7.0 and 7.5,DO was less than 1.0mg/L,T was between 22℃and 30.When C/N was more than 6,the effluent concentration of nitrate nitrogen was very low,the removal rate of nitrate nitrogen kept over 95%;when C/N was between 5 and 6,the removal rate of nitrate nitrogen decreased significantly,about 60%;When C/N was between 4.0 and 4.9,the removal rate of nitrate nitrogen decreased to below 50%.Thus when C/N was more than 6,carbon source was sufficient for the denitrifying bacteria.In summary,when using glucose as organic carbon source the best C/N is 6 in this experimental condition.2.During denitrification in Hybrid Biological Reactor,pH value showed slowly incresed with increasing the removal amount of nitrate nitrogen.Its range was between 7.0 and 7.5, weak alkaline was in Hybrid Biological reactor.when the removal amount of nitrate nitrogen was less than 20 mg/L,pH value was 7.0 in Hybrid Biological Reactor;while it was between 20 and 30 mg/L,pH value was between 7.1 and 7.3;while it was between 40 and 50 mg/L,pH value was between 7.4 and 7.5.3.When DO was less than 1 mg/L in Hybrid Biological Reactor, the removal rate of COD was more than 85%,and the degradation ability of denitrifying bacteria for organic compounds wasn't inhibited in this range,and the organic carbon source was fully used by denitrifying bacteria.When DO was more than 1mg/L, the removal rate of COD decreased,which showed that the denitrifying bacteria using organic carbon source was inhibited in this range,the reason was Buster effect.4.When DO was between 0.05mg/L and 0.9mg/L in Hybrid Biological Reactor,the denitrification effect of nitrate nitrogen was well,the removal rate of nitrate nitrogen did almost not change and kept over 95%.When DO gradually increased from the beginning of 0.9mg/L,the removal rate of nitrate nitrogen decreased to below 90%,and it gradually decreased with increasing DO concentration.However,when DO was between 1.3mg/L and 1.5mg/L,it still had a certain degradation ability in Hybrid Biological Reactor,the removal rate of nitrate nitrogen was between 68.4% and 88.1%.5.When COD influent concentration was between 300mg/L and 550mg/L, the removal rate of COD was relatively stable.Hence it showed that the microorganwasms had a good activity in Hybrid Biological Reactor during this concentration range.Therefore the degradation of organic compounds was effective. 6.If organic carbon source was abundant and only loading of nitrate nitrogen was changed,the removal rate of nitrate nitrogen almost keep over 95% in this experimental condition.The rate of denitrification as well as the removal rate of nitrate nitrogen was not restrictive by influent nitrate nitrogen loading..The main reason why the removal rate of nitrate nitrogen decreased was that influent C/N was relatively low,it couldn't meet denitrification demands for the organic carbon sources.7.In high and low shock loading test of organic and nitrate nitrogen,the removal rate of nitrate nitrogen did almost not change and the removal rate of COD had declined to a certain extent.When the shock loading was recovered to the normal level, the removal rate of COD recovered to the level before the test.Hybrid Biological Reactor has strong anti-shock loading capability.