Evaluating and modeling biogas production from municipal fat, oil, and grease and synthetic kitchen waste in anaerobic co-digestions

► Biogas from anaerobic co-digestion of kitchen waste (KW) and FOG was evaluated. ► KW and FOG enhanced CH4 production at estimated ideal S/I ratios of 1.20 and 0.46. ► Linear and modified Gomertz non-linear regressions combined to describe co-digestion. ► Models indicated that co-substrate addition can shorten lag phase of co-digestion. ► Evaluated S/I ratios and estimated parameters can support large scale operations.