Grease traps — including both manual grease traps and automated grease traps (also known as Automatic Grease Recovery Units or GRUs) — are essential tools for managing Fats, Oils, and Grease (FOG) in commercial kitchens. While both systems are designed to capture grease from kitchen wastewater, they differ significantly in how they operate, the costs involved, and long-term performance.
On the surface, an automated grease trap may appear more expensive than a manual alternative. However, there’s more to the story than just upfront cost. This guide explores the key differences between traditional grease traps and automated grease recovery units, helping you determine which solution is best for your commercial kitchen.
What is a Grease Trap?
A manual grease trap (also called a passive or hydromechanical grease interceptor) is commonly installed under sinks or in-floor within a commercial kitchen. These systems passively separate grease from wastewater using gravity. However, they require frequent pumping — often every 1–4 weeks — and can become inefficient if not cleaned properly, leading to blockages and unpleasant odors.
What is an Automated Grease Trap?
An automated grease trap, such as the Big Dipper Grease Recovery Unit, combines passive grease separation with an automatic mechanism that regularly removes grease and stores it in a sealed container. This motorized process eliminates the need for frequent pump-outs and allows kitchen staff to handle basic daily maintenance in just a few minutes.
These systems are designed to meet the same performance standards as manual grease traps (e.g. BS EN 1825 or PDI G101), with added requirements for effective grease skimming. They are compact, easy to install under sinks or counters, and contribute to long-term operational savings.
Cost Comparison: Manual vs Automated Grease Trap
While manual grease traps are cheaper upfront and have no electrical components, they require regular professional cleaning — a hidden cost that adds up quickly. In contrast, automated grease traps have higher initial purchase prices but dramatically lower maintenance and cleaning costs over time.
Example: Big Dipper W200 (Automated) vs AGT100 (Manual)
FactorManual Grease Trap (AGT100)Automated Grease Trap (Big Dipper W200)Purchase CostLowHigherDaily MaintenanceNone5 minutes of staff timeClean Out FrequencyEvery 4 weeksEvery 3 monthsPump-Out Cost£100–£200 per visit£150 per cleanRunning CostNone~£0.25/day
Over a 3-year period, the automated grease trap becomes the more economical option, with savings of nearly £600 — not including the potential for revenue from recycled grease.
Sustainability Advantage of Automated Grease Traps
Both manual and automated grease traps help prevent harmful FOG from entering the sewer system. However, automated grease traps offer a key sustainability benefit: the grease they recover is cleaner and more easily recycled into products like bio-diesel.
Manual grease traps often contain contaminated grease that cannot be reused, leading to more waste. In contrast, the automated grease recovery process isolates clean grease that can be collected and repurposed — adding an environmental and financial edge to automated systems.
Efficiency & Performance
Efficiency and performance depend on two critical factors:
- Certified Standards: Ensure your grease trap is tested to standards like BS EN 1825, PDI G101, or ASME A112.14.3.
- Correct Sizing: Grease traps must be sized according to flow rates and kitchen usage patterns. Undersized or incorrectly installed units — whether manual or automated — will not perform optimally.
You can use this grease trap sizing tool to find the right fit for your kitchen.
Final Thoughts
Choosing between a manual grease trap and an automated grease trap depends on your kitchen’s needs, budget, and long-term goals. While manual systems may seem more affordable at first, the total cost of ownership — including pump-outs, downtime, and inefficiency — often makes automated grease traps a smarter investment.
With advantages in cost savings, sustainability, and day-to-day convenience, automated grease recovery units like the Big Dipper W200 are quickly becoming the preferred choice for forward-thinking commercial kitchens.
Learn more: What Grease Traps Are and How They Work
