Seeing Through The FOG (Fats, Oils, And Grease)

By Douglas D. Sunday, water and wastewater Class A operator and Dr. J.H. Wakefield, consulting analytic chemist and environmental/materials engineer

A review of different methods and devices for FOG removal, with emphasis on cost control, lowered power profiles, and efficacy.

FOG deposits are the bane of the wastewater industry, affecting both the collection and treatment functions. Over the years, there have been many attempts to “get a handle” on this problem, and there have been many different ways proposed in these efforts. Let us examine one of the latest that is proving to be successful.

To begin with, we should understand both the chemical and physical identity of what actually comprises FOG deposits. They are an unholy “gemisch” of various lipids of widely different chemical and physical behaviors. They vary from oils (which are in liquid form) to greases (which may be solid or semisolid, depending on their chemical identities), to fats (which are usually solids, though they too may exhibit liquid or semisolid form), as well as waxes (which are almost always solids). They also can contain compounds that are lipid-soluble, such as steroids, various pharmaceutical agents, and even organic solvents.