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| Characterization of biofilm in denitrification biofilter based on microelectrode technique |
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Abstract In order to study the impact of dissolved oxygen (DO) on denitrification process in denitrification biofilter, microelectrodes with tip diameters of 30μm were fabricated to determine the microprofiles of O2 and NO3- in biofilms. Based on the profiles, a diffusion-reaction model was established to evaluate the microbial activities in terms of utilization rates of oxygen and nitrate. The results showed that the concentration of DO decreased rapidly along the depth of biofilm, which decreased from 1 mg/L in the bulk solution to almost 0 mg/L at 300μm depth of biofilm. Denitrification occurred in the depth zone of 300~600μm in the biofilm, and the ratio of oxygen uptake rate constant to denitrification rate constant was 1.46, which indicated the remarkable impact of DO on the denitrification process in biofilms.
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Received: 20 September 2011
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