Anaerobic digestion from residue of industrial cassava industrialization with acidogenic and methanogenic physical separation phases.
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.
Paixão
M A
MA
Chemical Engineering Department, State University of Maringá, PR, Brazil.
Tavares
C R
CR
Bergamasco
R
R
Bonifácio
A L
AL
Costa
R T
RT
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*
D002264:Carboxylic Acids; D003486:Cyanides; D008697:Methane