title: Effects of sulfide on the integration of denitrification with anaerobic digestion.
abstract: The effects of sulfide on the integration of denitrification with anaerobic digestion using anaerobic effluents of cassava stillage as carbon source were investigated. Batch tests indicated that nitrate reduction efficiencies decreased from 96.5% to 15.8% as sulfide/nitrate (S/NO3(-)-N) ratios increased from 0.27 to 1.60. At low S/NO3(-)-N ratios (0.27-1.08) anaerobic acidogenesis was accelerated. Nitrate was reduced to nitrite via sulfur-based autotrophic denitrification, after which the formed nitrite and residual nitrate were converted to N2 via heterotrophic denitrification. Increases in the S/NO3(-)-N ratio (1.60) caused a shift (76.3%) in the nitrate reduction pathway from denitrification to dissimilatory nitrate reduction to ammonia (DNRA). Sulfide concentrations (S/NO3(-)-N ratio of 1.60) suppressed not only heterotrophic denitrification but also acidogenesis. The potentially toxic effect of sulfide on acid production was mitigated by its rapid oxidation to sulfur, allowing the recovery of acidogenesis.
authors: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
authors: Zhixuan
authors: Z
authors: Yin
authors: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China. Electronic address: sally.xieli@tongji.edu.cn.
authors: Li
authors: L
authors: Xie
authors: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze River Water Environment, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
authors: Qi
authors: Q
authors: Zhou
mesh_terms: D000143:Acids / Q000378:metabolism; D000693:Anaerobiosis; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D058440:Denitrification; D052836:Heterotrophic Processes; D006863:Hydrogen-Ion Concentration; D002365:Manihot / Q000737:chemistry; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction; D013440:Sulfides / Q000378:metabolism*; D013455:Sulfur / Q000378:metabolism
chemical_list: D000143:Acids; D009566:Nitrates; D009573:Nitrites; D013440:Sulfides; D013455:Sulfur; D002244:Carbon
keywords: Anaerobic acidogenesis; Denitrification; Dissimilatory nitrate reduction to ammonia; Electron-flow; S/NO(3)(−)–N ratio