A critical review of fat, oil, and grease (FOG) in sewer collection systems: Challenges and control

ABSTRACT

Fat, oil, and grease (FOG) released into the sewer collection system have resulted in the production of insoluble solids, leading to FOG blockages in sanitary sewer pipes and consequently sanitary sewer overflows (SSOs). FOG-related SSOs continue to be a global challenge for municipalities responsible for maintaining the conveyance of wastewater in sanitary sewer systems. To provide a comprehensive understanding of FOG control in sewers, this paper critically reviews the scientific literature on the FOG deposit formation process, sources of components involved in FOG deposit formation, and solutions to the problems caused by FOG in sewer systems. The implications of these findings were also evaluated to provide support for pretreatment managers responsible for sewer collection system maintenance. Finally, the ongoing challenges in further understanding the FOG deposit formation process, the distribution of the sources of FOG/free fatty acids, the installation and maintenance of grease interceptors (GIs), and the recovery of energy from GI waste and FOG deposits, were also discussed to determine future research directions.

KEYWORDS:

• Fat
• oil
• grease (FOG)
• sewer blockage
• sanitary sewer overflows (SSOs)