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What is FOG?

What is FOG?

FOG is a widely used acronym for “fats, oil and grease,” the substances that most commercial kitchens produce as a byproduct of cooking and food preparation. Fats, oil and grease typically make their way into the wastewater when dishes are being washed or kitchen equipment is being cleaned.

Grease that collects in pipes and plumbing fixtures, in sewer lines and in sewage treatment plants creates numerous, expensive problems. As a result, most wastewater systems in North America and in many countries around the world require fats, oil and grease to be removed from wastewater before that effluent enters the sewer system.

When it’s not properly intercepted and trapped, grease creates significant problems. Metal and plastic, which are used in most sewer lines, are “oleophilic,” which means that grease adheres to those surfaces. That creates problems. Grease can:

  • Accumulate into large masses and clogs pipes, causing blockages and back-ups.
  • Collect on the floats used in sewage lift stations, with fist-sized floats growing to the size of basketballs. When this happens those lift stations malfunction, which can lead to back-ups.
  • Clog pumps at lift stations, treatment plants and the like. The pumps then must be repaired.
  • Lead to the creation of hydrogen sulfide (H2S), a poisonous gas. Certain kinds of bacteria that feed on fats, oil and grease release hydrogen sulfide, which smells like rotten eggs. This gas is potentially life threatening to people working in enclosed spaces, such as underground chambers built to access sewer lines. Mixed with water, these gases can also lead to increasing acidity levels, which causes metal and concrete infrastructure to corrode and eventually fail.

When grease accumulates and blocks sewer lines, expensive repairs are required. Thousands of such repairs are required to wastewater systems across the United States. In one widely publicized case in England, thousands of pounds of grease accumulated in a large sewer line, blocking it. It took workers weeks to clear the lines using high power hoses.

When restaurants or other food service establishments fail to install and properly maintain a grease interceptor to keep grease out of the sewer system, they will often end up paying for the shortsightedness.

If the grease causes a blockage and is traced back to its source, commercial kitchen operators can face substantial fines, plus bad publicity.