Fluidized bed biomethanation of acetic acid

An anaerobic attached film fluidized bed reactor was used to study the biomethanation of acetic acid at temperatures between 13 and 35C, feed substrate concentrations between 500 and 1500 mg COD per litre and hydraulic retention times between 1 and 8 h. At 35C, the experimental data were in good agreement with the predictions of Rittman's model, which reinforced the hypothesis that, at least at that temperature, the chemical reaction was governed by Monod kinetics. A reduction in hydraulic retention time was accompanied by a sharp increase in biomass loss. The attached biomass concentration was largely determined by the surface velocity across the bed. The diffusional resistances were negligible.