FOG (Fat, Oil & Grease) FAQ

The FOG - FAQ for Business - Filta Commercial Kitchens UK


As one of the leading providers of fat traps and grease management services we know a thing or two about FOG management. In this post we will go through the most common questions with regards to FOG for businesses.

What is Grease/FOG?

Fat, Oil and Grease (known as FOG) are carried in wastewater from commercial kitchens. It is the contamination of the wastewater with fats, oil, greases or food debris from the production and washing up of food equipment, utensils and crockery that causes blockages and the now infamous Fatbergs.

What is Grease FOG - Commercial Kitchen - Filta Environmental

What is Grease Management?

Foodservice kitchens produce wastewater that contains fats, oils and grease (FOGs) as well as food debris. If this wastewater is not managed in some way then these FOGs can be detrimental to the drainage/sewer network. This is a contravention of Section 111 of the Water Industry Act 1991. Grease Management is a term given to products/services that trap and/or treat the wastewater to reduce the amount of FOG within it before discharging to sewer. This is important in the ongoing fight against fatbergs like this “monster” fatberg from Devon.

What are the Grease Management Options?

There are 3 types of grease management system which either trap and/or treat wastewater to reduce FOG contamination:

  1. Grease TrapsGrease/fat traps, also known as separators or interceptors, these products physically trap the FOG within them and allow the cleaned wastewater to pass through.
  2. Grease Removal Units (GRU) Grease removal units have the same initial function of a grease trap with additional processes which remove food debris and FOG into external containers for separate disposal
  3. Dosing Systems – These add a biological element to the drainage system that is designed to break down the FOG into less harmful products.

All of these options are only effective if they are properly maintained. A combination of all of these options can be implemented.

Grease Management Options for Commercial Kitchens - Filta Environmental - UK

What Can Your Business Do to Reduce the FOG Entering Your Drains?

It is recommended that you install Grease Traps, GRUs and or Dosing Systems in your kitchen to manage the grease generated. Some equipment will require maintenance by site staff and others by professional grease management specialists. The most important aspect of any grease management equipment install is maintenance. Equipment needs to be installed with maintenance in mind so things such as access to covers and lids is an important design consideration. To reduce the overall FOG loading into your drainage network it is also recommended that you follow the best practice guidelines developed by Water UK regarding Disposal of Fats, Oils, Grease and Food Waste Best Management Practice for Catering Outlets.

What Equipment Generates FOG in Wastewater?

The equipment listed in BS EN1825 (the British Standard for Grease Separators) and identified as grease contamination points includes:

  • Pre-Rinse Sinks
  • Pot Wash Sinks
  • Dishwashers
  • Tilting Roasting-tin
  • Fixed Roasting-tin
  • High Pressure Cleaners
  • Scrapers
  • Vegetable Washer

Other equipment that may generate FOG contaminated wastewater includes: Wok Ranges, Steam Ovens, Combi Ovens, Brat Pans.

What Power Does my Water Company have to Prosecute Me?

The Water Industry Act 1991 (Section 111) gives the water companies the power to bring a criminal proceeding against anyone who causes injury or inhibits the free flow of the sewer network. FOG are included in this; therefore it is within their power to prosecute for FOG contamination.

They also have the power to ‘recharge’; this is when they charge users of the sewer network with any costs involved in clearing blockages or resolving environmental issues due to floods as a result of blockages. These charges can be considerable.

Water Companies can also work with their local government offices, specifically Environmental Health, to bring about ‘improvement orders’ and ‘prohibition orders’ to force a site to improve their practices.

FOG Contamination - Water Industry Act 1991 UK - Commercial Kitchen - Filta

What Other Bodies Can Prosecute Me?

Landlords, Local Government (Environmental Health, Food Standards), Environment Agency can also prosecute for breaches of FOG legislation.

Where Can I Dispose of my Grease Trap Waste?

The waste that collects within a grease trap or GRU is classified as a ‘Controlled Waste’. Therefore it should only be managed by a registered waste contractor such as Filta. The FOG recovered by GRU can be mixed with ‘Used Cooking Oil’ and collected by an authorised carrier. Anaerobic Digestion is preferred option for final disposal.

Filta Grease Management Specialist UK

FOG Management Specialists

If you do not have a grease management system in-place please contact the Filta Group on 01788 550100 to arrange a survey. Filta’s staff have been providing grease traps, grease separators and grease removal units for over 20 years. We provide a wide range of products and take care of all aspects from design and Water Company Approval to Installation and Maintenance. We are ISO9001 and ISO14001 accredited and members of the SafeContractor Scheme. To find out more please get in touch via or book a video call via our contact page.