How Does a Grease Trap Work, and Does Your Restaurant Need One?

When a local sewer issue arises, restaurants often find themselves under scrutiny as potential contributors to the problem. Fats, oils, and grease (FOG) that enter the drainage system can lead to costly blockages, environmental damage, and legal penalties. Authorities and water companies are increasingly vigilant, assessing how much FOG your establishment is releasing and ensuring compliance with UK regulations.

With substantial fines and reputational damage at stake, implementing an effective FOG management system is not just a compliance measure—it’s essential for maintaining a professional, sustainable, and efficient kitchen operation.

In this guide, we’ll cover:

How grease traps work
The differences between manual and automatic grease traps
Advanced FOG management solutions
Regulatory compliance in the UK
How to choose the right system for your kitchen

How Does a Grease Trap Work?

To understand how a grease trap functions, let’s start with basic science: oil and water don’t mix. Fats and oils are less dense than water, causing them to float to the top. Grease traps use this natural principle to separate and capture FOG before wastewater enters the drainage system.

The Process of FOG Separation:

Wastewater enters the grease trap from sinks, dishwashers, and cooking stations.
Flow slows down within the trap, allowing natural separation to occur.
Solids sink to the bottom of the trap.
Water continues to flow through the middle and exits to the drainage system.
FOG floats to the top and is trapped, preventing it from reaching the sewer system.

Without a grease trap, FOG would accumulate in the drainage system, leading to:

Drain blockages: Causing backups and costly repairs.
Foul odours: Due to decomposing fats and food debris.
Vermin attraction: Grease buildup can invite pests such as rodents and insects.
Environmental harm: FOG can contribute to water pollution and ecosystem damage.

Regular maintenance is crucial to ensure optimal performance and prevent operational downtime.

Manual vs. Automatic Grease Traps

Restaurants have two main options when it comes to grease trap solutions:

1. Manual Grease Traps

Pros:

Cost-effective initial investment
Simple installation
Suitable for small to medium-sized kitchens

Cons:

Require regular manual cleaning, typically every 2–4 weeks
Can become inefficient if not maintained properly
Risk of unpleasant odours if not emptied frequently

Material Options:

Stainless steel: Durable and long-lasting
Plastic: Lightweight and cost-effective

Manual grease traps have been in use for over a century and remain a reliable choice for smaller food service operations.

2. Automatic Grease Removal Units (AGRUs)

Pros:

Automatically removes grease at scheduled intervals
Reduces maintenance workload for staff
Improves kitchen hygiene by preventing FOG buildup

Cons:

Higher initial cost compared to manual traps
Still requires occasional professional cleaning

With an AGRU, FOG is collected daily into a removable container, making disposal easier and ensuring compliance with regulations. This solution is ideal for high-volume kitchens that generate significant amounts of grease.

Common industries using AGRUs:

Large restaurants
Hotels
Catering facilities
Food production units

Advanced Solutions for FOG Management

In addition to traditional grease traps, modern systems incorporate advanced technologies to enhance efficiency and sustainability. One such solution is BioCeptor, which combines mechanical grease trapping with bioremediation.

BioCeptor System: The Future of FOG Control

How it works: BioCeptor uses biological agents (biofluids) that digest FOG naturally, breaking it down into harmless byproducts.
Key benefits:

✔️ Extends the time between required cleanings (from 28 days to 12 weeks)

✔️ Reduces odours by breaking down grease at the source

✔️ Minimizes environmental impact and improves sustainability

Another effective strategy is using bio-dosing systems, which introduce friendly bacteria into the drainage system downstream of sinks and appliances to further break down FOG.

A layered approach, combining grease traps with bio-dosing solutions, ensures a comprehensive and proactive FOG management plan.

Who Needs a Grease Trap?

In the UK, regulations mandate that commercial food establishments have an appropriate grease management solution in place.

UK Building Regulations (Document H, Section 2.21):All commercial kitchens that serve hot food and are connected to mains drainage must install a grease separator or other effective grease removal system.

Businesses that require grease traps include:

Restaurants and cafes
Takeaways and fast-food outlets
Hotels and catering businesses
Schools and hospitals with canteens

Failure to comply can result in hefty fines, operational disruptions, and damage to your business’s reputation.

Why FOG Management Matters

Investing in proper FOG management solutions offers several benefits beyond compliance:

Prevents costly plumbing issues: Regular maintenance extends the lifespan of your drainage system.
Minimizes downtime: No unexpected disruptions due to clogs or repairs.
Protects the environment: Prevent harmful waste from entering local water sources.
Enhances your reputation: Show your customers and regulators that you care about sustainability.

With an increasing focus on environmental responsibility, having an effective grease management system also aligns with modern sustainability goals and corporate social responsibility initiatives.

Choosing the Right Grease Trap for Your Kitchen

Selecting the right grease trap depends on several factors, including:

Kitchen size and volume of food production
Type of food being prepared (greasy vs. low-fat)
Available space for installation
Budget for installation and maintenance
Compliance with local authority guidelines

At Via Equip, we specialize in helping businesses select the right grease management system that meets their specific needs and ensures full compliance with UK regulations.

Conclusion: Stay Compliant, Stay Efficient

Whether you opt for a manual grease trap, an AGRU, or an advanced bio-dosing solution, managing FOG effectively is crucial for the smooth operation of your kitchen. Taking proactive steps now can prevent costly issues down the line.

💬 Want to discuss your FOG management needs? Contact Via Equip today for expert advice and tailored solutions for your commercial kitchen.

📞 Get in touch with us now and keep your kitchen running smoothly and sustainably!