Sugarcane Bagasse as Carbon Source and Filler to Enhance the Treatment of Low C/N Wastewater by Aerobic Denitrification Flora

Abstract

Sugarcane bagasse as a biomass solid waste has good prospects as a carbon source for biological wastewater treatment. However, it has rarely been investigated for aerobic denitrification (AD). Herein, we investigated its carbon release performance and constructed a bagasse-loaded sequencing batch biofilm reactor (SBBR) to investigate the feasibility of sugarcane bagasse as a carbon source and filler for AD bacteria to treat wastewater with low carbon–nitrogen ratios (C/N). Results showed that chemical oxygen demand (COD) leaching from sugarcane bagasse was 418.07 ± 17.05 mg/g; high-temperature and high-pressure operation had no significant effect on the carbon release performance of the bagasse. A shake-flask experiment revealed that adding sugarcane bagasse significantly enhanced the AD flora denitrification effect in low C/N wastewater; the removal process of NO3−–N by AD flora followed first-order kinetics. In the SBBR inoculated with AD flora, biofilm formation on the bagasse surface was evident; the NO3−–N removal rate reached 20.20 ± 4.27% after 28 operation cycles, which was significantly higher than that of the control sequencing batch reactor during the same period, and the effluent COD stabilized below 50 mg/L. The results provide a reference for AD application in the practical wastewater treatment and biomass resource utilization of sugarcane bagasse.