Abstract

Total nitrogen (TN) in tannery wastewater is difficult to remove completely, because the low C/N ratio of the wastewater leads to inadequate denitrification. Sodium acetate was used as an extra carbon source to improve the denitrification efficiency and the TN removal. The appropriate COD/TN ratio for denitrification using sodium acetate was 5.1, at which the TN concentration of tannery wastewater decreased by 95%. A much faster removal of TN was obtained by adding sodium acetate in denitrification than by adding common glucose. These results showed that sodium acetate was a high-quality carbon source for a complete and rapid denitrification of tannery wastewater. The denitrification efficiency decreased with decreasing temperature and increasing chloride concentration. However, when the carbon source was made sufficient by adding sodium acetate, complete denitrification was still obtained even at 15°C or 10000mg/L of chloride concentration.