Optimization of biohydrogen and methane recovery within a cassava ethanol wastewater/waste integrated management system.
Thermophilic co-fermentation of cassava stillage (CS) and cassava excess sludge (CES) were investigated for hydrogen and methane production. The highest hydrogen yield (37.1 ml/g-total-VS added) was obtained at VS(CS)/VS(CES) of 7:1, 17% higher than that with CS digestion alone. The CES recycle enhanced the substrate utilization and improved the buffer capacity. Further increase the CES fraction led to changed VFA distribution and more hydrogen consumption. FISH analysis revealed that both hydrogen producing bacteria and hydrogen consuming bacteria were enriched after CES recycled, and the acetobacteria percentage increased to 12.4% at VS(CS)/VS(CES) of 6:2. Relatively high efficient and stable hydrogen production was observed at VS(CS)/VS(CES) of 5:3 without pH adjusted and any pretreatment. The highest total energy yield, the highest COD and VS degradation were obtained at VS(CS)/VS(CES) of 7:1. GFC analysis indicated that the hydrolysis behavior was significantly improved by CES recycle at both hydrogen and methane production phase.
State Key Laboratory of Pollution Control and Resources Reuse, Tongji University, 1239 Siping Road, Shanghai 200092, PR China.
Wen
W
Wang
Li
L
Xie
Gang
G
Luo
Qi
Q
Zhou
Qin
Q
Lu
D001673:Biodegradation, Environmental; D056804:Biofuels / Q000032:analysis*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D000431:Ethanol / Q000737:chemistry*; D005232:Fatty Acids, Volatile / Q000032:analysis; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D017404:In Situ Hybridization, Fluorescence; D002365:Manihot / Q000737:chemistry*; D008697:Methane / Q000378:metabolism*; D008970:Molecular Weight; D013816:Thermodynamics; D018505:Waste Management / Q000295:instrumentation / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000295:instrumentation
D056804:Biofuels; D000431:Ethanol; D005232:Fatty Acids, Volatile; D006859:Hydrogen; D008697:Methane; D062065:Wastewater