A grease trap is a plumbing device designed to intercept and retain fats, oils, and grease (FOG) from wastewater before it enters the main sewage system. Galvanized steel traps are especially favored in commercial kitchens due to their durability, corrosion resistance, and ease of installation. They are coated with a layer of zinc to prevent rusting, making them an ideal choice for high-moisture environments like kitchens.