Control of Carbon and Nitrogen Ratio for Nitrogen Removal of Aerobic Denitrifier in a Batch Reactor

An aerobic denitrifier (X31) derived from sewage sludge has been used for the biological denitrification under aerobic environment. 16S rDNA sequencing indicates X31 is a stain of Pseudomonas sp. Succinate was used as the carbon source for X31 aerobic denitrification. Results showed that over 97% denitrification rate was achieved when succinate was applied. When the initial COD/N ratio was adjusted to 6, almost 95% nitrate removal was achieved. No sign of nitrite accumulation was detected and the residue nitrite was below 1.5 mg/L and the residue nitrate was 4.33 mg/L under a C/N of 6. The nitrogen removal efficiency was little changed with increasing COD/N ratio. Medium pH increase was observed along with ORP decrease during the course of the aerobic denitrification process.