- Grease traps, also known as grease interceptors, separate fats, cooking oil, and grease from wastewater before it enters the sewer system. Collectively referred to as FOG, fats, oil and greases can clog systems, causing them to back up. Laws regulating grease traps primarily pertain to commercial establishments. Facilities such as laundries, restaurants and nursing homes must use grease interceptors and maintain them properly. While regulations vary among jurisdictions, a few are common everywhere.
- Wastewater processed through a grease trap--commonly called effluent--must also flow through a septic tank. The grease trap removes the FOG from the water, but residual oils and greases remain in suspension. Further processing of the effluent through a septic tank removes the remaining FOG before the wastewater is discharged into the sewer.
- The distance between the trap's inlet and outlet must be sufficient to allow the FOG to settle and separate from the wastewater. In addition, the inlet and outlet connections are set low in the tank to prevent grease from escaping through the outlet.
- Adequate ventilation must be present in the grease trap to eliminate air locks. Vents are routinely incorporated into the cover. Without the ability to breathe, flow within the tank is restricted.
- A sealed cover must be installed on the tank to prevent odor from escaping and insects from entering the grease trap. The cover also must provide access to the tank for maintenance and cleanout purposes.
- Ground-up garbage from a disposal must not pass through a grease trap before entering the septic tank. Food particles will disrupt the separation process of FOG in the grease trap, backing up the system.
- A certified engineer must size the grease trap for each facility or building for which one is installed. Proper sizing depends on the local governing regulations and the daily calculated flow of wastewater anticipated to flow through the system.
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