Enhanced Nitrogen Removal of Low C/N Wastewater in a Subsequent Denitrifying Reactor Fed by Endogenous Carbon Source Generated from Primary Sludge Fermentation
A novel post-denitrification system fed by carbon source from primary sludge (PS) was used for enhancing biological nitrogen removal (BNR) of low C/N wastewater. This system included one anoxic/oxic (AO) reactor and a special reactor for simultaneous sludge fermentation and denitrification (Sifeden). Ammonia was nitrified to nitrate in AO and then the nitrate was reduced to dinitrogen in Sifeden , into which PS was added intermittently. Results showed that this system had high performance on nitrogen removal. Total nitrogen (TN) removal efficiency was higher than 85% and the effluent TN≤10mg/L in the condition of influent C/N≤2. In Sifeden, volatile fatty acid (VFA) produced from PS fermentation provided electron donor for nitrate reduction, and PS was preliminarily stabilized simultaneously. Oxidation-Reduction Potential (ORP) had a significant correlation with the denitrification performance. TN removal efficiency could be further improved if adopting proper PS addition strategy according to the ORP profiles.
Zhenyu Du and Chengbin Li
C. C. Wu et al., "Enhanced Nitrogen Removal of Low C/N Wastewater in a Subsequent Denitrifying Reactor Fed by Endogenous Carbon Source Generated from Primary Sludge Fermentation", Advanced Materials Research, Vol. 281, pp. 101-105, 2011