Grease traps and grease interceptors perform similar functions—i.e., preventing fats, oils, and grease (FOG) from leaving a kitchen facility and entering the sewer system. These compounds are byproducts of cooking that stem from food materials containing fats and oils, such as meat and dairy products. When disposed of down a drain, they can stick to the inside of sewer pipes, which, over time, causes buildups, blockages, and other serious problems.
The following article provides an overview of grease traps and interceptors, including what they are, how they work, key selection considerations, and who uses them.
Understanding Each Grease Device
What is a grease trap?
A grease trap is a small FOG removal unit designed for use in kitchen applications where the flow of water and amount of oil and grease produced is low. It is typically installed beneath the sink inside the kitchen facility.
How does a grease trap work?
Wastewater flows from the sink of the drain into a tank, where the FOG hardens and the solids settle. As FOG is lighter than water, it floats to the top of the trap, allowing only wastewater to flow out into the sanitary sewer or septic system.
What is a grease interceptor?
A grease interceptor is a large FOG removal unit. It is generally installed beneath large-scale kitchen facilities that produce a large amount of grease and have higher flow rates and pressures.
How does a grease interceptor work?
A grease interceptor works the same way as the grease trap but at a much larger scale.
Do I Need a Grease Trap or a Grease Interceptor?
A grease trap or grease interceptor is required for any facility that pushes wastewater with fats, oils, or grease into the sewage system.
When deciding between a grease trap or a grease interceptor for a commercial kitchen facility, there are a few factors to keep in mind, including:
- Unit size. Grease traps are much smaller (typically about the size of bread box to a small mini-fridge), while grease interceptors are much larger.
- Capacity/flow. Grease traps handle flow rates of 10–50 gallons per minute, while grease interceptors accommodate flow rates of more than 50 gallons per minute.
- Pressure. Grease traps work best in a low-pressure water environment, whereas grease interceptors are more appropriate for high-pressure environments.
- Installation. Grease traps typically are fitted beneath the sink inside of the kitchen, while grease interceptors are installed outside and beneath the concrete.
- Maintenance intervals. Grease traps require regular maintenance every day or month (depending on size), while grease interceptors need it every few weeks or months.
Manage Your Grease Traps & Interceptors With Help From the Experts
When using a grease trap or grease interceptor, it is important to perform regular cleaning and maintenance operations. Otherwise, they can cause blockages, backups, overflows, and/or foul odors that can affect the quality and profitability of the food establishment, nearby buildings, and surrounding environment.
During these operations, it is essential to take state and local plumbing codes into consideration. For example, Massachusetts’ 310 CMR 15.000 Regulation for grease trap maintenance is as follows:
- 310 CMR: DEPARTMENT OF ENVIRONMENTAL PROTECTION 15.351: Grease traps shall be inspected monthly by the owner/operator and cleaned by a licensed septage hauler whenever the level of grease is 25% of the effective depth of the trap, or at least every three months, whichever is sooner. The owner/operator shall keep all inspection and pumping records.
- Each city and town in MA requires individual licensing and permitting for septage hauling. Make sure your hauler is licensed in your city or town.
- Septage haulers are required to fill out a System Pumping Record and submit it to the local Board of Health or Regulatory Agency within 14 days of pumping.
For assistance cleaning a grease trap or grease interceptor, turn to the experts at Service Pumping & Drain. We offer grease trap maintenance services for units ranging in size from 20 liters to a few metric tons. Our other service offerings include water jetting, septic system maintenance, catch basin and storm drain cleaning, and 24-hour emergency maintenance.
As we serve the eastern Massachusetts area, we are careful to follow all applicable state codes to ensure our clients remain in compliance. We get it right the first time, so they don’t have to worry. For more information about grease traps or grease interceptors and how to maintain them, contact us today.