Fat, Oil and Grease (FOG) is not restricted to particular types of menu or cooking styles. Fats and oil are derived from oils, meat, fish and dairy products, and almost all types of preparation and cooking generate waste FOG.
FOG (Fat, Oil & Grease)

What are Grease Traps and How Do They Work?

Fat, Oil and Grease (FOG) is not restricted to particular types of menu or cooking styles. Fats and oil are derived from oils, meat, fish and dairy products, and almost all types of preparation and cooking generate waste FOG.

Recently, the way foodservice operators dispose off FOG has come under increased scrutiny because of the potential volume of FOG that can be produced as a result of the activity and the concentrations of foodservice operations in the same area sharing the same sewer network. [source BW COP2]

An estimated four to five hundred tonnes of grease is discharged into the sewers every year resulting in hundreds of thousands preventable blockages. The right equipment will prevent the fat, oil and grease entering the sewer network, reducing the risk of flooding, blockages and bad smells.As a result, legislation ensuring that adequate fat, oil and grease management is used is now being heavily enforced. Polluters can expect large fines or even closure if fat, oil and grease is not managed well.

Fat, oil and grease (FOG) also causes problems for staff / operators in commercial kitchens, with fat, oil and grease (FOG) from wastewater causing blockages in internal pipes leading to expensive repairs, bad smell and possible downtime.​

What are Grease Traps and How do they Work?

Grease traps have been around since the 19th century and have many different names FOG trap, grease separators, grease interceptors, grease catchers, grease management devices or Grease Recovery Units (GRU)

- Cafes
- Takeaways
- Restaurants
- Pubs, bars and inns
- Hotels
- Bakeries
- Schools and colleges
- Hospitals & more

The principle behind grease traps is simple: grease floats on water.
- So why are there so many types of grease interceptors?
- And how are you supposed to know which is best for your commercial kitchen?

Let’s start with the basics: A grease trap is something kitchen wastewater flows through before entering the sewer waste system. This receptacle — technically a grease interceptor — intercepts, captures, or "traps" grease. How?

How do grease traps work?

Grease is 10 to 15 percent less dense than water and doesn’t mix with water. This results in grease (FOG - fats, oils grease) floating on top of water.

When wastewater enters a grease trap, the flow rate is reduced often using baffles. This allows for the lighter less dens oil particles to raise to the top inside the interceptor. Solids settle at the bottom and the separated clear water is allowed to escape.

See how a grease interceptor like Trapzilla works!

Read more on grease traps

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Q: Why is venting a grease trap so important? A: Water isn’t the only thing flowing into your grease trap. Air gets in, too. As water levels rise inside your grease trap, this air compresses. This isn’t just any air, either. It’s some of the funkiest air you’ll ever smell. Without proper grease trap venting, it will affect you in one of two ways:

Q&A on venting Grease Traps

Q: Why is venting a grease trap so important? A: Water isn’t the only thing flowing into your grease trap. Air gets in, too. As water levels rise inside your grease trap, this air compresses. This isn’t just any air, either. It’s some of the funkiest air you’ll ever smell. Without proper grease trap venting, it will affect you in one of two ways:

July 1, 2022
Written by Andrew Crook published in FFR For many years I have had issues with the drains at my shop, not regularly, but every so often there will be a blockage. My shop is on a parade of shops which are mostly occupied by food premises. In the past, previous owners of some of the takeaways have been caught pouring used cooking oil down the drain so when we have had a blockage, I always put it down to the other operators as the drains run my way. With the Government’s Environment Bill currently ‘ping ponging’ between the House of Lords and the Commons, and Cop26 taking place as I write this, it’s a good time to explore this issue.

Fat, Oil & Grease - It can't be me blocking the drains... can it?

Written by Andrew Crook published in FFR For many years I have had issues with the drains at my shop, not regularly, but every so often there will be a blockage. My shop is on a parade of shops which are mostly occupied by food premises. In the past, previous owners of some of the takeaways have been caught pouring used cooking oil down the drain so when we have had a blockage, I always put it down to the other operators as the drains run my way. With the Government’s Environment Bill currently ‘ping ponging’ between the House of Lords and the Commons, and Cop26 taking place as I write this, it’s a good time to explore this issue.

July 1, 2022
It's Monday and it feels this could be the best week ever. Well-rested from the weekend, time off all the work issues as well as a much-needed break and quality time. Thriving from Monday energy, to-do list are crossed of at super sonic speeds, coffee a pleasure not a necessity and tasks are getting done quicker than expected. Would it not be nice to carry this momentum through the week?

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It's Monday and it feels this could be the best week ever. Well-rested from the weekend, time off all the work issues as well as a much-needed break and quality time. Thriving from Monday energy, to-do list are crossed of at super sonic speeds, coffee a pleasure not a necessity and tasks are getting done quicker than expected. Would it not be nice to carry this momentum through the week?

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