Alternative stillage treatment scenarios. Either the liquid fraction of the stillage is anaerobically digested (A), or the whole stillage is fed directly to anaerobic digestion (B). The dotted parts are optional, see Table 1 for details. The wastewater streams, such as the condensed flash streams from pretreatment and drying, are also sent to anaerobic digestion but they are not shown here. BF: belt filter; FP: filter press.