Adaptation of biomass in a batch reactor Granular sludge from a stabilized anaerobic process for thetreatment of vinasse was used as inoculum; an Erlenmeyerflask glass of 2 L with constant stirring was used for theadaptation and growth of biomass before to be feedingto the UAF reactor. The reactor operated in batch modeat 37 ± 2◦C, and pH from 6.8 to 7, adjusted with NaOH,with a volume of wastewater of 1.6 L. A sludge volume of20% (v/v) with respect to the reactor volume reaction wasused with a volatile suspended solids (VSS) concentrationof 8500 mg VSS L−1. The reactor was initially fed with a CODconcentration of 350 mg L−1, corresponding to 10% of thewastewater COD concentration; then COD concentration wasgradually increased in 10%, until reaching the COD concentra-tion of the effluent (3500 mg L−1); by replacing the equivalentvolume of wastewater with the required COD concentration.Each load lasted 48 h; this time assures the organic mat-ter degradation greater than 50% and in consequence biogasproduction.