How Does a Grease Trap Work in Commercial Kitchens?
If you’ve ever worked in or managed a commercial kitchen, you’ve likely heard of a grease trap. But what is it exactly? And how does it work? A grease trap might not seem like a big deal, but it’s one of the most important parts of keeping a kitchen clean, efficient, and compliant with health and safety rules.
In this blog post, we’ll break down everything you need to know about grease traps supply and installation—how they work, why they’re important, and how they help kitchens run smoothly without plumbing problems. We’ll keep it simple and easy to follow.
What Is a Grease Trap?
Understanding the Basics
A grease trap, also called a grease interceptor, is a plumbing device designed to stop fats, oils, and grease (FOG) from entering the main sewage system. These substances, when poured down the drain, can cool and harden, causing serious clogs in pipes.
Commercial kitchens, such as those in restaurants, hotels, and cafeterias, produce a large amount of FOG daily. That’s why a grease trap is essential in these places—it acts like a filter that catches the greasy waste before it creates problems.
Why Are Grease Traps So Important in Commercial Kitchens?
The Role They Play
If grease isn’t properly separated from wastewater, it can:
- Block kitchen pipes
- Create bad smells
- Cause backups and overflows
- Lead to expensive repairs
- Violate health and safety laws
In many cities, including Dubai and other areas around the UAE, grease traps are required by law in commercial kitchens. Regular inspections are often carried out by the local municipality.
How Does a Grease Trap Actually Work?
Let’s get into the step-by-step process of how a grease trap works once it’s installed in your kitchen.
1. Wastewater From the Sink Enters the Grease Trap
Starting Point – The Kitchen Sink
When you wash dishes, clean pans, or rinse food trays, the wastewater goes down the sink. This water carries all kinds of waste, including:
- Bits of food
- Soap
- Water
- Fats, oils, and grease (FOG)
This mixture flows into the inlet pipe of the grease trap.
2. Separation Happens Inside the Grease Trap
Natural Separation by Density
Inside the grease trap, something important happens—the separation process. Grease traps use a simple but smart method based on the weight of the different substances in the water.
Here’s How It Works:
- Grease and oil are lighter than water, so they float to the top.
- Solid food particles are heavier than water, so they sink to the bottom.
- Clean water stays in the middle layer.
The trap holds this water inside long enough for this natural separation to happen.
3. Clean Water Flows Out
Once the water has settled, it flows out through the outlet pipe, which is placed near the middle of the tank. This pipe only lets the cleaner water escape into the sewer system.
All the fats, oils, and solids stay inside the grease trap and are trapped there, just like the name says.
What Are the Main Parts of a Grease Trap?
Understanding the parts helps you know how the system works and what needs maintenance.
Main Components of a Grease Trap
1. Inlet Pipe
Where the wastewater from the kitchen enters the trap.
2. Interior Chamber
The main area where separation takes place. It may be one or more compartments depending on the trap size.
3. Baffles
Walls or dividers inside the trap that slow down the flow and help with the separation process.
4. Outlet Pipe
This pipe carries the filtered water out of the trap and into the drainage system.
5. Lid or Cover
A secure lid that allows for inspection and cleaning.
Types of Grease Traps in Commercial Kitchens
There are different kinds of grease traps used in businesses, and the choice depends on how big the kitchen is and how much grease is produced.
Common Types
1. Passive Grease Traps (Manual)
- Usually installed under the sink
- Good for small restaurants or cafes
- Need to be cleaned regularly by hand
2. Gravity Grease Interceptors (GGIs)
- Installed underground outside the building
- Handle larger volumes of waste
- Cleaned by professional pumping services
3. Automatic Grease Removal Units (AGRUs)
- Use mechanical parts to remove grease automatically
- More expensive but need less manual cleaning
- Great for kitchens with heavy daily use
Where Are Grease Traps Installed?
Placement Is Important
Grease traps are placed based on how your kitchen is set up.
Common Locations:
- Under the sink (for small grease traps)
- In the kitchen floor (for moderate setups)
- Outside, underground (for large systems)
A professional installer will help you choose the best location to make cleaning and maintenance easier.
How Often Should a Grease Trap Be Cleaned?
Cleaning Is Key to Performance
Even the best grease trap won’t work if it’s full. Over time, the grease builds up and blocks the flow of water. This leads to bad smells, backups, and potential health violations.
General Cleaning Guidelines:
- Small under-sink traps: Clean every 1–2 weeks
- Medium traps: Clean monthly
- Large interceptors: Clean every 3–6 months (by professionals)
Some kitchens may need more frequent cleanings, depending on usage.
Who Installs and Maintains Grease Traps?
Leave It to the Experts
Installing a grease trap the right way is not a DIY job. It needs:
- Correct sizing
- Proper plumbing connections
- Compliance with local laws
That’s why it’s important to hire licensed professionals who specialize in commercial kitchen grease trap installation and maintenance.
Benefits of Using a Grease Trap in Commercial Kitchens
More Than Just Compliance
Having a grease trap gives you more than just a clean kitchen.
1. Protects Your Pipes
Stops clogs and reduces the need for plumbing repairs.
2. Keeps the Environment Clean
Prevents grease from polluting water systems.
3. Avoids Fines
Meets health and safety laws and avoids legal trouble.
4. Improves Kitchen Smell
Reduces bad odors caused by grease buildup.
Signs Your Grease Trap Needs Attention
Know When It’s Time to Clean or Fix It
Watch for these warning signs:
- Water draining slowly
- Smell of rotten food or grease
- Grease on top of the water in sinks
- Overflow or backup from the drain
If you see any of these, it’s time to call a professional for cleaning or repair.
Conclusion: Grease Traps Keep Kitchens Running Smoothly
A grease trap might be hidden under the sink or buried underground, but it plays a huge role in keeping your commercial kitchen working the right way.
It prevents blockages, keeps your plumbing safe, and helps you follow the rules. Understanding how it works—and keeping it clean—will save you money, protect your business, and ensure smooth kitchen operations.
So if you’re opening a new restaurant or just want to upgrade your existing kitchen, don’t forget the importance of a quality grease trap installed and maintained by the pros.
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