title: Anaerobic digestion from residue of industrial cassava industrialization with acidogenic and methanogenic physical separation phases.
abstract: A trial was carried out in a continuous regimen, using a completely stirred tank reactor, at acidogenic phase, and a hybrid reactor (upflow anaerobic sludge blanket + fixed bed) at methanogenic phase at room temperature. The residue to be treated came from a flour and cassava meal industry, and the reactors operated for 300 d with affluent chemical oxygen demand (COD) concentrations of 7500, 9000, 11,000, and 14,000 mg/L. The final results showed a biogas production with a content of 80% methane and an average reduction of COD and free cyanide of nearly 96 and 98%, respectively. The separation of phases selected bacterial groups. At acidogenic phase, a predominance of propionic, n-butyric, and n-valeric acids, as well as a biomass composed of 95% fermentative bacilli, which were responsible for a 90% reduction in free cyanide concentration, was observed. At methanogenic phase, a predominance of methanogenic bacteria that came only from the Methanothrix genus was observed. The bacteria were responsible for high levels of organic matter removal and methane production.
authors.affiliation: Chemical Engineering Department, State University of Maringá, PR, Brazil.
authors.forename: M A
authors.initials: MA
authors.lastname: Paixão
authors.forename: C R
authors.initials: CR
authors.lastname: Tavares
authors.forename: R
authors.initials: R
authors.lastname: Bergamasco
authors.forename: A L
authors.initials: AL
authors.lastname: Bonifácio
authors.forename: R T
authors.initials: RT
authors.lastname: Costa
mesh_terms: D000693:Anaerobiosis; D018533:Biomass; D002264:Carboxylic Acids / Q000032:analysis; D003486:Cyanides / Q000032:analysis*; D019605:Euryarchaeota / Q000502:physiology*; D005285:Fermentation; D005433:Flour; D005511:Food Handling; D002365:Manihot; D008697:Methane / Q000032:analysis*
chemical_list: D002264:Carboxylic Acids; D003486:Cyanides; D008697:Methane