One of the byproducts of large-scale commercial food operations is liquid food waste. This waste includes animal and vegetable fats, oils, and grease (FOG). Left untreated, these FOG drain into the municipal sewer system, where they accumulate and eventually cause massive sewer backups. These backups damage public infrastructure and are both expensive and time consuming to repair. Untreated restaurant discharge, also known as effluent, can also cause problems in municipal wastewater treatment facilities.

Because of this, the Environmental Protection Agency (EPA) mandates the pretreatment of liquid waste released into municipal sewer systems. The goal is to remove FOG from the effluent. The removal of FOG is to keep the sewer lines unrestrained and flowing. Grease removal systems, including grease interceptors and grease traps, are intended for this purpose.

Installation
Grease interceptors installation comes after the various kitchen drains but ahead of the sewer lines. The contents of the drains collect in the grease interceptor. As long as the FOG does not emulsify, it does not mix well with water. Being heavier than water, the FOG will separate and float to the surface, where it accumulates to be removed by a skimmer. Afterward, the FOG-free wastewater moves into the sewer system. The grease collected can be recycled and used as biodiesel fuel.

Grease interceptors can be adapted for installation in a variety of situations. A high water table may precipitate the need for outdoor installation. On the other hand, limited outdoor space may require the interceptor to be installed below the sewer system, with the addition of a pump system to pump the water to the sewer.

Tanks Direct furnishes both fiberglass underground systems and aboveground stainless steel units. These systems are installed inside buildings.