Evaluation of bioenergy recovery processes treating organic residues from ethanol fermentation process.
This study evaluates a two-stage bioprocess for recovering bioenergy in the forms of hydrogen and methane while treating organic residues of ethanol fermentation from tapioca starch. A maximum hydrogen production rate of 0.77 mmol H(2)/g VSS/h can be achieved at volumetric loading rate (VLR) of 56 kg COD/m(3)/day. Batch results indicate that controlling conditions at S(0)/X(0)=12 with X(0)=4000 mg VSS/L and pH 5.5-6 are important for efficient hydrogen production from fermentation residues. Hydrogen-producing bacteria enriched in the hydrogen bioreactor are likely utilizing lactate and acetate for biohydrogen production from ethanol-fermentation residues. Organic residues remained in the effluent of hydrogen bioreactor can be effectively converted to methane with a rate of 0.37 mmol CH(4)/g VSS/h at VLR of 8 kg COD/m(3)/day. Approximately 90% of COD in ethanol-fermentation residues can be removed and among that 2% and 85.1% of COD can be recovered in the forms of hydrogen and methane, respectively.
Department of Environmental Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan.
Chun-Po
CP
Juang
Liang-Ming
LM
Whang
Hai-Hsuan
HH
Cheng
D000085:Acetates / Q000378:metabolism; D056804:Biofuels / Q000032:analysis*; D019149:Bioreactors; D002087:Butyrates / Q000378:metabolism; D002264:Carboxylic Acids / Q000032:analysis; D003246:Conservation of Energy Resources / Q000379:methods*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007773:Lactates / Q000378:metabolism; D008320:Maltose / Q000032:analysis; D008697:Methane / Q000378:metabolism; D009930:Organic Chemicals / Q000737:chemistry*; D014865:Waste Disposal, Fluid
D000085:Acetates; D056804:Biofuels; D002087:Butyrates; D002264:Carboxylic Acids; D007773:Lactates; D009930:Organic Chemicals; D000431:Ethanol; D008320:Maltose; D006859:Hydrogen; D008697:Methane