A FACT SHEET FOR
Restaurant Oil and
Grease Rendering
Grease Gebfin
Introduction
Improperly managed oil and grease from restaurants has
become a significant problem for wastewater collection and
treatment systems. Fats, oils, and greases (FOG) coat, con¬
geal, and accumulate in pipes, pumps, and equipment, lead¬
ing to the costly and hazardous flow of waste grease into
drain lines, sewer lines, lift stations, drain fields, and Pub¬
licly Owned Treatment Works (POTWs). Improper disposal
can result in high biological oxygen demand (BOD) and
chemical oxygen demand (COD) levels, increased operat¬
ing costs, and clogged collection systems. Approximately
30% of the 3,800 reported sewer system overflows in North
Carolina in 1998 were caused by FOG blockage of the sew¬
ers.
Where Does Grease Go
When It Leaves a Restaurant?
A grease trap is designed to prevent grease, oil, solids, and
other debris from entering the waste stream, where it be¬
comes a problem by clogging sewers and disrupting the water
flow in the system. The grease trap captures those wastes
and contains them until a rendering company can properly
dispose them.
A grease trap should be checked and maintained to ensure
it is working properly. Backups, odors, and drainage prob¬
lems are signs that the grease trap is not functioning as it
should.
Grease Recycling
While pretreating wastewater through the use of grease traps,
skimmers, separators, and process flow treatment systems
such as carbon filtration or coagulation units can greatly
reduce the problem, source reduction of oil and grease must
be the first course of action. Through dry cleanup, the de¬
velopment of an efficient collection system and rendering
program, wastewater problems can be avoided. Rendering
companies or “grease recyclers” will accept oil, grease, and
other animal byproducts, including deep fry fat and bones,
thereby turning a nuisance waste material into a beneficial
product such as animal feeds.
OCTOBER 1999
NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES
DIVISION OF POLLUTION PREVENTION AND ENVIRONMENTAL ASSISTANCE
NCDENR 1639 MAIL SERVICE CENTER ■ RALEIGH, NC 27699-1639