Effects of C/N Ratio on Nitrate Removal from PU Synthetic Leather Wastewater Treated by Anoxic Moving Bed Bio-film Reactors

One sample of PU synthetic wastewater was analyzed, its Total Nitrogen (TN) was mainly composed of about 300 mg/L nitrate, and three pieces of anoxic Moving Bed Bio-film Reactors (MBBR) were applied to treat it, one MBBR was run with raw wastewater, the second and third were with synthetic wastewater, and the results were as followings: TN could be removed off completely under the condition of relative low C/N ratio; the C/N ratio of removed pollutants was liner correlation with C/N ratio of influent, but the C/N ratio of effluent was increase violently, the above results demonstrated that, the external carbon source, necessary to the heterotrophic bacteria, was consumed more rapidly than nitrate nitrogen in initial denitrifying stage, then the nitrogen was utilized much more rapidly at later stage, and the ratio of C/N denitrification behaved as a chamfer linear.