Fatburg Ahead! - the UK wakes up to the problem of fat, oil and grease

Fatburg in London Sewer system


With news this week of a 15 tonne grease blockage reported to be as large as a ‘London Bus’ in the sewer system of South West London Watling Hope look at the options to restaurateurs and private customers to prevent a ‘cataclysmic’ drain failure.

The ‘Fatburg’ was widely reported in the UK media, from BBC's Today programme to the UK's printed media - and even as far away as the Canadian website Metro News

So what is a Fatburg?
A ‘Fatburg’ is a large lump of grease which collects in the sewer system, this builds up over time from fat, oil and grease discharged into the drains from private houses and restaurants. Whilst its title may sound amusing the consequences are not. By restricting the flow through the sewer system this can directly lead to pollution of rivers and coastal areas as waste is diverted through overflows (CSOs) instead of being allowed to flood pupulated areas.

It is also very difficult to clear presenting a major health and safety challenge to water utility engineers as they work to clear it in a running sewer system.

Where is the fat coming from?
Fat, oil and grease (known in the water treatment industry as FOG) enters the drainage systems of commercial premises from washing of pots, pans, plates and utensils. In warm water FOG is in suspension and can be easily washed into the drain-line, however once the effluent cools the FOG comes out of suspension and forms a sticky coating on the walls of the pipe-work. Left untreated this fatty-coating will build-up and in so doing will reduce the throughput of the pipe. Once the bore has been significantly reduced it is a matter of time before there is a complete and catastrophic blockage.

How can we stop Fatburgs occurring?
The fat in Fatburgs comes from washing of pots, pans and plates. This is from private users and commercial customers. Residential users of the sewer system can prevent fat, oil and grease entering the drain-line by adopting good kitchen practices – very simply by not washing fat down the sink but wiping pans with kitchen towel and placing in the refuse bin. For commercial customers its essential to manage grease using a grease management system; this can be either by installing a grease trap or by treating the drain line with fat-degrading bacteria.

'But we don't cook Fatty-Food?'
A common misconception is that fat, oil and grease is only a problem for kitchens where food is grilled or fried. On the contrary - fat and oil in kitchen drainage is derived from oils, meat, fish and dairy preparation and increasingly the use of combination steaming ovens.

Do I need a grease trap or grease treatment system?
If you  produce food and as a result wash-up pots, pans and utensils onsite you will be producing FOG. Even a B&B producing 10 meals per day will be generating significant build-up of fat, oil and grease in the drainage system which will in time lead to bad odours and ultimately a blockage.

What is the legislation surrounding grease traps and grease management?
 For existing premises the reasons for fitting a FOG management system tend to be as a result of drain problems, pressure from the local authority, landlord or environmental health. It is however a requirement under the Water Industry Act 1991 to ensure that your premises does not discharge any product into the drain which may interfere with its operation.

  • Water Industry Act 1991 - Provisions protecting sewerage system
    111 Restrictions on use of public sewers
    (1) Subject to the provisions of Chapter III of this Part, no person shall throw, empty or turn, or suffer or permit to be thrown or emptied or to pass, into any public sewer, or into any drain or sewer communicating with a public sewer-
    (a) any matter likely to injure the sewer or drain, to interfere with the free flow of its contents or to affect prejudicially the treatment and disposal of its contents
  • Utility enforcement - Thames Water reported that in 2007/2008 over 60,500 sewer blockages reported were caused in part by FOG.
    With the cost running into Millions of Pounds Water Authorities are more and more adopting a 'polluter pays' principle where they will trace the problem back to the offender. The Thames Water website states "During 2007/08, we saw the continued success of the fat, oil and grease pollution prevention programme of targeting blockage hotspots, with a further 1,501 visits undertaken at food service establishments across our catchment."
  • Bitish Building Regulations - For new-builds fitting a grease trap or grease removal system is a statutory requirement in the UK under Part H of the British building Regulations. Part H states under item 2.21 - "Drainage serving kitchens in commercial hot food premises should be fitted with a grease separator complying with prEN 1825-1and designed in accordance with prEN 1825-2 or other effective means of grease removal." PrEN 1825-1 (now BSEN 1825) is the European standard for gravity grease interceptors. The standard provides guidance purely for separators sizes where FOG is to be removed by gravity alone. Gravity separators are very large and not often practical for retro-fit. The British

Watling Hope provide a wide-range of grease traps, grease removal units and drain treatment systems.

We work with many of the UK’s leading restaurants and some large private houses.

We are a member of British Water and provide free surveys in London and across the UK.

If would like to find out how you can stop the Fatburg - call us we are here to help.



Safe Contractor British Water

Request a call back in

Enter your name and number and a consultant will call you back.