title: Unraveling the influence of the COD/sulfate ratio on organic matter removal and methane production from the biodigestion of sugarcane vinasse.
abstract: Throughout the sugarcane harvest, it is common for sulfate to accumulate in the vinasse of sugar and ethanol plants. However, little is known regarding the influence of sulfate on the anaerobic digestion (AD) of vinasse, which may lead to severe performance losses. This study assessed the influence of various COD/sulfate ratios (12.0, 10.0 and 7.5) on both COD removal and methane (CH4) production from sugarcane vinasse AD. Batch assays were conducted in thermophilic conditions. At a COD/sulfate ratio of 7.5, CH4production was 35% lower compared with a ratio of 12.0, considering a diversion of approximately 13.6% of the electron flow to sulfidogenesis. The diversion of electrons to sulfidogenesis was negligible at COD/sulfate ratios higher than 25, considering the exponential increase in CH4production. Organic matter degradation was not greatly affected by sulfidogenesis, with COD removal levels higher than 80%, regardless of the initial COD/sulfate ratio.
authors.affiliation: Biological Processes Laboratory, São Carlos School of Engineering, University of São Paulo, 1100 João Dagnone Avenue, 13563-120 São Carlos, SP, Brazil. Electronic address: luma.kiyuna@gmail.com.
authors.forename: Luma Sayuri Mazine
authors.initials: LSM
authors.lastname: Kiyuna
authors.affiliation: Biological Processes Laboratory, São Carlos School of Engineering, University of São Paulo, 1100 João Dagnone Avenue, 13563-120 São Carlos, SP, Brazil. Electronic address: ltfuess@sc.usp.br.
authors.forename: Lucas Tadeu
authors.initials: LT
authors.lastname: Fuess
authors.affiliation: Biological Processes Laboratory, São Carlos School of Engineering, University of São Paulo, 1100 João Dagnone Avenue, 13563-120 São Carlos, SP, Brazil; Brazilian Bioethanol Science and Technology Laboratory (CTBE), Brazilian Center for Research in Energy and Materials (CNPEM), 10000 Giuseppe Máximo Scolfaro Street, 13083-970 Campinas, SP, Brazil. Electronic address: zaiat@sc.usp.br.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Zaiat
mesh_terms: D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D005232:Fatty Acids, Volatile / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008697:Methane / Q000096:biosynthesis*; D009930:Organic Chemicals / Q000302:isolation & purification*; D031786:Saccharum / Q000737:chemistry*; D013431:Sulfates / Q000032:analysis* / Q000302:isolation & purification; D013440:Sulfides / Q000032:analysis; D013997:Time Factors; D014865:Waste Disposal, Fluid; D014866:Waste Products / Q000032:analysis*
chemical_list: D005232:Fatty Acids, Volatile; D009930:Organic Chemicals; D013431:Sulfates; D013440:Sulfides; D014866:Waste Products; D008697:Methane
keywords: Bioenergy recovery; Kinetic assessment; Sugarcane biorefinery; Sulfate reduction; Vinasse biodigestion