Grease Trap vs. Grease Interceptor: What’s the Difference?

Fats, oils and grease (FOG) are produced every day in settings with a commercial kitchen, and the only way to tackle the damage FOG can cause is with a grease trap or grease interceptor. Both systems effectively stop FOG from travelling to the sewer line, reducing the risk of blockages, overflows due to fatbergs and pollution and health hazards, which all lead to increased maintenance costs. 

There are many different types of grease traps and grease interceptors, with the way they work mostly unchanged since their inception way back in the 1880s. 
To say grease traps and interceptors are crucial is an understatement. But what is the difference between a grease trap vs interceptor?

What Is a Grease Trap?

What Is a Grease Interceptor?

7 Key Differences (Grease Trap vs Interceptor)

Benefits of Using a Grease Trap or Interceptor

Which System Does Your Business Need?

A grease trap is a system installed in commercial kitchens that separates fats, oils and grease (FOG) from wastewater.

Grease traps effectively prevent FOG from damaging a commercial kitchen’s plumbing system and the wider sewage system. As FOG solidifies in the captured wastewater, a series of baffles cause the FOG and heavier food particles to separate from the wastewater. This is to prevent blockages, protect the local and wider drainage systems and ensure commercial kitchens comply with wastewater regulations.

The size of a grease trap will range from the size of a small box to the size of a mini fridge. Above ground grease traps are small enough to fit below a kitchen sink.

Commonly known as above ground grease traps and ideal for small-to-medium sized commercial kitchens. 

Grease traps are typically installed underneath kitchen sinks or close enough to the source of grease production, like dishwashing stations.

Grease traps can be found in many premises that prepare and cook hot food, including cafes, restaurants, hotels, offices and schools.
For more details around the function of grease traps, read our detailed guide on exactly how grease traps work.

A grease interceptor is the name for a large-scale grease trap. A grease interceptor will most likely be installed underground, coining the name below ground grease interceptor. 

A grease interceptor functions the same as a grease trap, but on a much larger scale. Wastewater flow is slowed and enters the grease interceptor, where FOG floats and settles at the top for separation. 

A main difference between a grease trap and grease interceptor is the scale of each. Grease interceptors are suited for larger kitchens and premises to effectively capture high volumes of FOG.

A commercial kitchen will require a grease interceptor if the flow rate is above 50 gallons per minute. The required size typically depends on factors such as the number and type of sinks or kitchen fixtures, the flow rate of wastewater entering the system, the volume of food preparation and washing taking place, and local regulations. 

Grease interceptors are normally installed underground, outside of the building, between the kitchen drainage system and the main sewer line. Their external location allows them to handle larger wastewater volumes and makes them easier for maintenance teams to access for cleaning. 

Like grease traps, grease interceptors are used across commercial kitchens, retail, cafes, educational premises and hotels. However, grease interceptors are typically chosen when these premises deal with large volumes of wastewater, or when the premises don’t have access to the sewage system, and instead use large wastewater storage tanks. 

A grease trap will be installed underneath a commercial kitchen sink, where washing up and waste management takes place, with accessible integration into smaller plumbing systems. 

A grease interceptor will be installed outside of the commercial kitchen either above ground, or most likely buried below ground. This provides a non-invasive solution to handle large amounts of FOG waste for high-capacity kitchens.

Installed under each sink located inside commercial kitchens

Daily cleans are necessary for both grease traps and interceptors, with employees taking on this role. Proper maintenance and more substantial cleans can be completed weekly, bi-weekly or monthly. More comprehensive cleans and maintenance services for grease interceptors especially are best conducted by a specialist, like Aqua Mundus. 

In the battle of grease traps vs grease interceptors, one of the biggest differences is the capacity of each system. Grease traps are designed for lower volumes of FOG and wastewater, while grease interceptors have larger capacities to support large-scale premises. 

With the grease trap being installed underneath a commercial kitchen sink vs a grease interceptor which is installed outside the kitchen and typically below ground.

Ideal for small cafes, small fast food outlets, bakeries, small restaurants

Suited for large restaurants, hotels, hospitals, shopping centres, large-scale fast food outlets and high-volume commercial kitchens

With a grease trap dictating its location under sinks, the size generally ranges from 40-60 cm in length, 20-40 cm in width and 20-40 cm in height. Being much larger and located underground, a grease interceptor will generally measure 1.5-3 m in length, 1.5-5 m in width and 1-2 m in height.

Approximately 40 cm x 20 cm x 20 cm (L x W x H)

Approximately 1.5 m x 1.5 m x 2 m (L x W x H)

These are approximate measurements and of course they will vary. You can use our size calculator to establish the right sized system for your premises. 

Thanks to their smaller size and capacity, grease traps can be emptied by hand on a daily basis by employees, with best practice being at the start and end of each day. Grease interceptors will require appointed specialists to pump the stored FOG and then be safely and legally disposed of.

Require specialist pumping services to empty

Steel, plastic, PVC and fibreglass are common materials used for the design and construction of grease traps. However, without proper maintenance, these materials can rust and break, causing costly replacement. Grease interceptors are made of materials designed to withstand higher amounts of FOG and flow rates.

Steel, plastic, PVC and fibreglass to withstand lower volumes of FOG and flow rates

Whether you need a grease trap or a grease interceptor to best suit your establishment, each provides plenty of benefits, including:

Most commercial kitchen establishments will use a grease trap installed underneath each wash station or sink. Small kitchens that have flow rates below 50 gallons per minute, such as kitchens in cafes, small restaurants and takeaway shops, will require a grease trap. They will effortlessly fit into even the smallest of premises with limited space and separate lower grease amounts from wastewater.

Large kitchens with multiple wash stations and flow rates above 50 gallons per minute will require a grease interceptor. Premises include hotels, hospitals, large restaurants, universities and industrial kitchens. These settings with larger kitchens produce significantly more FOG and might not have access to the main sewer line, meaning grease interceptors will be installed underground and connected to a wastewater tank. 

If you run a commercial kitchen of any kind, big or small, you need a grease trap to effectively and legally manage FOG waste. The experts at Aqua Mundus can help you decide on the right choice as well as fully install and maintain your grease traps, keeping your business running, legally compliant and protecting the environment. Contact us today to discuss your needs.