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.