With so many sizes and styles of grease traps it’s easy to get completely confused. Some are the size of rooms, ones that go in the ground, others that go under sinks, some have skimming devices and baskets other use chemicals and bacteria. How can all these solutions be accepted?
The answer is in most countries there are standards to follow and design criteria’s. The first place to start is to ask your local water authority what is permitted and what is not. This might narrow down the options but if you still don’t know what size is required then here is a quick guide.
Grease needs time and space to separate. The bigger the volume the more time inside it for grease to separate. The European Standard states that for a restaurant that does about 100 meals per day a grease trap of around 360 litres is required. This usually needs to go into the ground and must be emptied once a month or when the liquids volume is 25% full of grease. The installation outside can be costly as can the maintenance required and oftentimes there simply is no space to put them outside. If you have a basement it can go there but this may make empting the tank harder.
You may be directed to put a Model under the sink instead, especially when you have no space outside or a basement. This method is very appealing because it’s cheap and easy to get one installed compared to digging up the yard. The downside is they have to be emptied regularly which for a 100 litre grease trap could be every two weeks to ensure efficiencies are maintained. The cost of doing so is not long adding up and you may be tempted to ignore pump outs but leave it too long. Some companies will suggest dosing the grease with enzymes and chemicals which is an ongoing cost with varying degrees of success. Enzymes and bacteria are seen by most water authorities as a solution for the restaurant but not necessarily for the municipality.
This is where automatic grease removal (GRU) units come into the equation. A GRU is a grease trap with a method of removing the grease automatically. The idea is that rather than have pumpers in every month the GRU will remove the grease for you, leaving it in a container that can be easily handled and disposed of or recycled by staff. You save on pump out costs and the unit remains efficient. GRUs tend to be more expensive initially but cost less in the long run.
Always check what your local authority permits before ding on which trap to use.