A numerical method to simulate and assess the formation of Fats, Oils & Grease (FOG) deposits in a sewer collection system

Many urban centers are faced with a growing number of food service establishments (FSEs) and multifamily communities that may lead to an increase in the amount of fats, oil, and grease (FOG) discharge into the wastewater stream. This FOG, when exposed to calcium in wastewater, develops solids through a saponification reaction that may lead to line blockages and sanitary sewer overflows (SSOs). Sewer line blockage from FOG deposit formation is one of the most frequently cited concerns and maintenance headaches by pretreatment coordinators. 48% of SSOs in the United States are due to FOG deposits, which lead to exposure of untreated sewage to the public. This research is focused on a computer model (CITY DRAIN) to simulate sewer collection system and FOG related blockages that predict probable new blockages caused by the ever changing urban landscape. The results of this research could be used as a tool by pretreatment coordinators to improve sewer line maintenance and reduce the potential for future SSOs.