Grease Traps and Automated Grease Recovery units are one of the most common (Fats, Oils and Grease) FOG Control solutions. Manual or passive and automatic grease traps being the most widely accepted devices for commercial kitchen operators. Both devices are marketed as performing essentially the same job of separating fat, oil and grease from kitchen wastewater. At first look automatic grease traps seem very expensive compared to manual grease traps. There is more than meets the eye and additional factors should be consider than just the initial purchasing cost of the unit.
FOG (Fat, Oil & Grease)

Automatic Grease Traps vs Manual Grease Traps

Grease Traps and Automated Grease Recovery units are one of the most common (Fats, Oils and Grease) FOG Control solutions. Manual or passive and automatic grease traps being the most widely accepted devices for commercial kitchen operators. Both devices are marketed as performing essentially the same job of separating fat, oil and grease from kitchen wastewater. At first look automatic grease traps seem very expensive compared to manual grease traps. There is more than meets the eye and additional factors should be consider than just the initial purchasing cost of the unit.

Grease Traps and Automated Grease Recovery units are one of the most common (Fats, Oils and Grease) FOG Control solutions. Manual or passive and automatic grease traps being the most widely accepted devices for commercial kitchen operators.

Both devices are marketed as performing essentially the same job of separating fat, oil and grease from kitchen wastewater.  At first look automatic grease traps seem very expensive compared to manual grease traps. There is more than meets the eye and additional factors should be consider than just the initial purchasing cost of the unit.

The two system types will be explained in this article, highligitng the main differences as well as the pros and cons of each system.

Manual or Passive grease traps
Passive or Manual Grease Trap

Hydromechanical grease interceptors / separators (most often referred to as grease traps) often sit inside the kitchen underneath the sink or in the floor. They passively trap grease over time and need to be pumped frequently, sometimes as often as every week. They may be less expensive up front, but they cost more overtime due to frequency cleaning. If not cleaned out regularly, they may become inefficient start to smell and block the drains.

Automatic grease traps or Grease Recovery Units
Big Dipper Automated Grease Recovery Unit (GRU) 

Automatic grease recovery  devices or automated grease traps are offer an alternative to hydromechanical grease interceptors in kitchens. While their tanks passively intercept grease, they have an automatic, motorised mechanism for removing the grease from the tank and isolating it in a container. These interceptors must meet the same efficiency standards as a passive HGI, but must also meet an additional standard that proves they are capable of skimming the grease effectively.They are often designed to be installed unobtrusively in your commercial kitchen, in a corner or underneath a sink. The upfront cost of these units is higher, but maintenance can be handled by the kitchen staff. That eliminates regular pumping charges and reduces operating costs.

Furthermore the recovered Fat, Oil and Grease (FOG) is to a quality that can be recycled to use in Bio-Diesel or other applications. Keeping your kitchen free from blockages.

There is more information on What Grease traps are and how they work

Cost, Sustainability, Efficiency and Performance

The previous section explained each of the Grease trap system, the next section will look closer at sustainability, cost, efficiency and performance

Cost

Often the purchasing decision is based on upfront cost or purchasing price between a manual or automatic grease trap. Neglecting that there are other costs consideration when buying any type of grease trap. Costs to consider are:

- Purchase Costs‍
- Running Costs
- Daily Maintenance Costs
- Grease Removal or pumping cost

The automatic grease trap can be 4-5 times higher than the purchase cost of a 100l passive trap. Manual traps also have no moving parts require no electricity, unlike a Big-Dipper automatic grease trap which need around 5 minutes of maintenance a day and require an electricity supply to function.

Therefore it is easy to assume that passive or manual trap is the cheaper more cost effective solution. However this does not include pump out costs swing the comparison in the favour of automatic grease traps. Manual traps require pumping out every 2-4 weeks at a cost of between £100 and £200, whereas automatic traps only require a clean out every 3-6 months at the same cost.  Therefore over the course of 3 years, automatic traps will be much cheaper overall.

To compare to similar automatic and manual grease traps, the Big-Dipper W200 (automatic) and AGT100 (manual), so you can see which one will cost you less over a 3-year period.

The figures below are based on the following:

Daily maintenance costs = 5 minutes of labour @ £12 per hour
Running costs = £0.25 per day
Clean out costs = £150
Cleaning intervals for Big Dipper W200 Automatic Grease Trap = Every 3 months
Emptying intervals for AGT100 Manual Grease Trap = Every 4 weeks

Cost Comparison Big Dipper W200 vs Passive Trap

Clearly the Big Dipper W200 automatic grease recovery units are more expensive than the manual grease trap in the first year, mainly due to the high equipment price. However, by the end of year 2, the much higher clean out costs of the manual unit mean the overall cost is higher its automatic counterpart. After 3 years, the cost difference between the 2 units is nearly £600 in favour of the automatic Big Dipper. If you also add potential income from selling recovered oil from the automatic unit, the cost difference increases even more. Not to mention reduction in odour, ease of maintenance, longevity and staff satisfaction.

Although automatic grease traps require a higher initial investment, the additional features gained by the extra investment offer increased performance, potential for additional revenue and reduced long term costs, making automatic grease removal units the best choice for grease management in commercial kitchens.

Sustainability

Capturing grease in commercial kitchens helps prevent FOG entering the sewerage system, therefore any kind of grease trap is beneficial. However, what happens to the recovered grease?

With passive grease traps, the grease contractor will empty and dispose of all substances removed from the trap. The grease will often not be recycled as it is of poor quality and full of impurities such as food waste.

GRUs such as Big Dipper remove grease automatically and deposit it into a crease collector without impurities . The recovered grease can be collected with used cooking by your relevant service provider. Potentially, if enough grease is collected, the removed grease from automatic grease traps can be sold.

Therefore the automatic grease recovery units have the upper hand on sustainability. Due to both extra revenue generated and better raw material (grease) recovered.

Efficiency & Performance

There are two key elements to efficiency and performance. First this needs to be measured to an accredited standard such as BS EN 1825, PDI 101 or ASME. Secondly the unit needs to be sized correctly for it to work and flows to the grease trap have too correspond to flows during the performance test to get to similar separation efficiencies.

Contact us if you like to know more about the best Grease Trap for your project

Latest Articles

View All
We use the term “Those two mix like oil and water,” when describing two people who don’t like each other. Maybe you’ve also noticed shimmering oil floating on the surface of water on the road after it rains. In both cases you understand that water and oil don’t mix well —but have you ever wondered why? So many other things can dissolve in water—why not oil? In this activity we’ll explore what makes oil so special.

What does the phrase "Those two mix like oil and water" really mean?

We use the term “Those two mix like oil and water,” when describing two people who don’t like each other. Maybe you’ve also noticed shimmering oil floating on the surface of water on the road after it rains. In both cases you understand that water and oil don’t mix well —but have you ever wondered why? So many other things can dissolve in water—why not oil? In this activity we’ll explore what makes oil so special.

May 20, 2022
While the first part of the article established that any treatment claims made for dosing systems are dubious at best, it now turns out that even cost effectiveness is questionable and only works if biological dosing systems are operated in a low or standard setting. Increasing the dosing intensity immediately effects the running cost of an enzyme dosing system and very quickly tips the overall cost in favour of an automated grease retention unit.

Cheap enzyme dosing grease management, busting the cheap grease trap myth. Dosing vs grease trap

While the first part of the article established that any treatment claims made for dosing systems are dubious at best, it now turns out that even cost effectiveness is questionable and only works if biological dosing systems are operated in a low or standard setting. Increasing the dosing intensity immediately effects the running cost of an enzyme dosing system and very quickly tips the overall cost in favour of an automated grease retention unit.

May 12, 2022
There might be as many opinions on this question as there are people in the room. However, fact is that a block drain has a knock on effect. Block drains often result in the kitchen shutting down until experts have resolved the blockage and in some extreme cases there is water damage in lower level sections of the building. While every blockage has different effects here is an idea on the cost

What is the true cost of inefficient FOG (Fat, Oil & Grease) Control

There might be as many opinions on this question as there are people in the room. However, fact is that a block drain has a knock on effect. Block drains often result in the kitchen shutting down until experts have resolved the blockage and in some extreme cases there is water damage in lower level sections of the building. While every blockage has different effects here is an idea on the cost

May 1, 2022