Grease interceptors (also known as grease traps, grease recovery devices and grease converters) are plumbing devices designed to intercept mostgreases and solids before they enter a wastewater disposal system. Common wastewater contains small amounts of oils which enter into septic tanksand treatment facilities to form a floating scum layer. This scum layer is very slowly digested and broken down by microorganisms in the anaerobic digestion process. However, very large amounts of oil from food production in kitchens and restaurants can overwhelm the septic tank or treatment facility, causing a release of untreated sewage into the environment. Also, high viscosity fats and cooking greases such as lard solidify when cooled, and can combine with other disposed solids to form blockages in drain pipes.