page_title: Grease trap
section_title: Uses
hierarchical_section_title: Grease trap / Uses
caption_attribution_description: In-Ground Grease Trap outside of a Ramen Shop
context_page_description: A grease trap is a plumbing device designed to intercept most greases and solids before they enter a wastewater disposal system. Common wastewater contains small amounts of oils which enter into septic tanks and treatment facilities to form a floating scum layer. This scum layer is very slowly digested and broken down by microorganisms in the anaerobic digestion process. Large amounts of oil from food preparation in restaurants can overwhelm a septic tank or treatment facility, causing release of untreated sewage into the environment. High-viscosity fats and cooking grease such as lard solidify when cooled, and can combine with other disposed solids to block drain pipes.
  Grease traps have been used since Victorian days: Nathaniel Whiting obtained the first patent in the late 1800s. The traps reduce the amount of fats, oils and greases that enter sewers. They comprise boxes within the drain run that flows between the sinks in a kitchen and the sewer system. They only have kitchen waste water flowing through them, and do not serve any other drainage system, such as toilets. They can be made from many different materials, such as stainless steel, plastics, concrete & cast iron.
context_section_description: Restaurant and foodservice kitchens produce much waste grease which is present in the drain lines from various sinks, dishwashers and cooking equipment such as combi ovens and commercial woks. If not removed, the grease can clump and cause blockage and back-up in the sewer.
  In the US, sewers back up annually “an estimated 400,000 times, and municipal sewer overflows on 40,000 occasions”. The EPA has determined that sewer pipe blockages are the leading cause of sewer overflows, and grease is the primary cause of sewer blockages.  Even if accumulated FOG does not escalate into blockages and sanitary sewer overflows, it can disrupt wastewater utility operations and increase operations and maintenance requirements” 
  For these reasons, depending on the country, nearly all municipalities require commercial kitchen operations to use some type of interceptor device to collect grease before it enters sewers.  Where FOG is a concern in the local wastewater system, communities have established inspection programs to ensure that these grease traps and/or interceptors are being routinely maintained.
  It is estimated 50% of all sewer overflows are caused by grease blockages, with over 10 billion US gallons (3.8×10¹⁰ l; 8.3×10⁹ imp gal) of raw sewage spills annually.
caption: In-ground grease trap outside of a shop
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