Study on the Influence of DO to Simultaneous Nitrification and Denitrification in Catching Bed Biofilm Reactor

Abstract- The nitrogen removal effect of catching bed biofilm reactor based on traditional biofilm process was investigate. The result indicates, steady removal effect with 87.81% of average COD removal rate was achieved in various dissolved oxygen(DO) concentrations.When DO was between 0.7~1.1 mg/L, removal rate for NH₄⁺-N and TN 94.7% ,53.8%,respectively.When DO was controlled in 1.2~2.0 mg/L, 94.7% of average NH₄⁺-N removal rate and 79.66% of average TN removal rate were obtained. When DO was between 2.0~3.5 mg/L, average removal rates for NH₄⁺-N and TN were 99.6% and 65.1% respectively. The optimal condition for nitrogen removal effect was with DO between 1.0~2.0 mg/L. pH was also a crucial factor for removal rates of NH₄⁺-N and TN. The preferable effect for simultaneous nitrification and denitrification was found between 7.05~7.37 of pH.