This section outlines the methodology for addressing aims (a) and (b). have been proposed to characterize the identified biowaste streams (aim (a)), along with key questions to answer which are outlined in Table . Based on the five criteria, the waste streams can be evaluated and assessed, to identify the most attractive source for further pretreatment, aim (b). In general, the selected waste stream is required to be available at large quantities (1) and with relatively stable supply from year to year (2). While upgrading a waste stream from use as an energy source to material recovery (upgrade within the waste hierarchy) is advisable, focusing on underutilized waste