Sludge Digester Liquors Treatment by Enhancing Denitrification with Internal Carbon Source

摘要

Separate treatment of reject water of digested sludge could reduce the nitrogen load of the wastewater treatment plant and improve the final effluent quality. In the biological treatment process, however, external organic carbon was always required for stable denitrification. In this study, a novel system using primary sludge as the electron donor was developed for nitrogen removal of reject water. In particular, post denitrification was accomplished by simultaneous primary sludge fermentation and nitrite reduction in a specific reactor. Effluent recycling to the nitrification reactor significantly improved nitrogen removal. TN removal efficiency was 88.1% and effluent TN was 48.0 mg/L at steady conditions. Decrease of TN removal was observed was observed at a low temperature due to the incomplete nitrification process. The results indicated post denitrification process with addition of primary sludge can be a suitable biotechnology for nitrogen removal of reject water.