Restaurants and institutions such as hospitals and nursing homes need to dispose of grease in large quantities. In fact, there are specific regulations that ensure that grease is not released into the sewer system which could cause a backup of untreated sewage into the environment. Grease, lard and oil solidify when cooled and this can cause blockages or drain clogs.
Grease traps go all the way back to the 1800’s and they are basically boxes within the drain that catch grease and solids before they enter the sewage disposal system. Common wastewater at your home will contain a small amount of oils that is slowly broken down in the septic system. When large amounts of grease and oil are used, a grease trap is needed.
Restaurants and institutions may use an interceptor, which is a larger capacity in ground tank. The brown grease is pumped out and taken to the landfill. Today there is also the option to use a GRD (Grease Recovery Device) which will automatically remove recovered grease and yellow grease can be recycled.