Building Regulations Part H states `Drainage serving kitchens in commercial hot food premises should be fitted with a grease separator`, this is usually directed at new build premises or at buildings that are to have a change of use however there is talk of this being enforced on a wider scale.
What Are Grease Traps
Grease traps are a chamber that allows the grease and fat to be separated from the waste water via a series of baffle walls or dip pipes, they come in several forms and can be above or below ground, and the size of the unit will depend on the volume of water passing through it and they will often have a stainless steel basket inside so that heavy debris and large deposits of grease and fat can be lifted out and disposed of.
The original units we find in schools and city centre restaurants are often brick built chambers but we do come across large vitrified clay units, modern below ground grease traps are constructed from plastics or fibre glass.
The Problem With Grease Traps
The main problem with grease trap is lethargy, it’s not a nice job emptying or cleaning these things out and you are unlikely to find a volunteer for the job in your average catering establishment, and of course it costs money to get a drainage contractor or waste disposal company in to do the job so they are often left well alone until they clog up and fail.
The positioning of a grease trap is also vital in its ongoing maintenance and emptying but when kitchens are situated in basements or there is little or no outside space many of these traps are located beneath the busy kitchen floor, we have worked on premises run by the larger fast food chains where we have a three hour window in the middle of the night between shift changes to do the works. This is understandable because you will always get a certain amount of odour lingering for a while once you lift the cover of an internal grease trap but with many of these restaurants now open for 24 hours a day it is possible that the essential maintenance works will be put on hold until the 11th hour.
Above Ground Grease Traps
Many modern day catering establishments will have stainless steel or plastic above ground grease traps sited around the kitchen, often used in conjunction with a biological dosing unit that use enzymes and bacteria to break down grease and fat within the grease trap before it is dispersed into the drainage system.