Lifting the Fog from FOG Receiving

Fats, oils, and grease (FOG) often causes problems within collection systems, but represents a potentially high-energy feedstock for anaerobic digestion that can increase onsite energy production. Numerous facilities have implemented FOG receiving systems to reduce collection system overflows and increase digester gas production. However, as the number of such facilities has grown, so have reports of operational difficulties. Ten facilities were surveyed to determine a number of parameters, including operational practices, system configuration and equipment used, operation and maintenance (O&M) requirements, and benefits realized after implementation of FOG receiving. Digestion of FOG did increase digester gas production at most facilities, allowing several to meet or exceed most of their energy demands. However, FOG handling and system maintenance can be cumbersome and the delivered product can be highly variable in quantity, quality, and characteristics. Harnessing the energy inherent in FOG can significantly offset energy demand, but careful consideration of the practical aspects of FOG receiving is necessary for sustainable and successful operations.