Fat, Oil and Grease Frequently Asked Questions

Who are Aqua Mundus?
To find our more visit our ‘About Us’ page or phone 01386 832205 to discuss further.


What’s the legislation for fat, oil 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.
Taken from the 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
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."
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 Building Regulations therefore takes a practical view and allows the use of "other effective means of grease removal" which can refer to biological dosing equipment or automatic grease separators.

Water UK - Best Management practice:
"Grease traps/grease interceptors Grease traps are specially designed units which are placed in drain pipes to separate the fat, oil and grease from the rest of the wastewater. The wastewater then continues to flow to the sewage works for treatment while the grease is retained in the trap to be collected by a licensed waste oil collector at regular intervals. These units can be highly effective if they are correctly installed, serviced and maintained.
A written record of maintenance must be kept. Your local environmental health officer may be able to assist on the location and size of the unit to suit your premises to ensure it is efficient at preventing the grease causing problems in the drains."


Water UK - Water UK
Building Regulations – Part H 2.21 Building Regulations Part H section 2.21Download Building Regulations Part H


About Grease Management Systems

What are Grease Traps and Grease Interceptors?
Grease traps have been used since the Victorian days. They are used to reduce the amount of fats, oils and greases (FOG’s) that enter the main sewers. Effectively they are boxes within the drain run that flows between the sinks in a kitchen to the foul sewer system. They only have waste water flowing through them and are not served by any other drainage system such as toilets. They can be made from a number of different materials; e.g. Stainless Steel, Plastics, Concrete & Cast Iron. They range from 5 litre capacity to 30,000 litres and above capacity. They can be located above ground, below ground, inside the kitchen or outside the building.

What happens to the grease?
The trapped grease is stored in the trap until it is cleaned out.

Do I need a Grease Trap?
Most Local Authorities require a system to prevent grease and fat from flowing into the main sewerage system. Even if it is not required, you may want a Grease Trap to help prevent clogged drains from stopping work.

How does a Grease Trap or Grease interceptor work?
By slowing down the flow of hot greasy water and allowing the grease to cool. As it cools, the fat, oil and grease separate and float to the top of the Grease Trap. The clean water continues to flow down the waste pipe.

What happens if I don't have a Grease Trap or Grease Interceptor?
Drains block and waste water backs up. Even partial drain blockages can cause floor drains to back-up, causing pollution. Also, this stops work and may require expensive maintenance.

What else can I do to prevent blocked drains?
Fat, oils and grease cling to other solids in your waste water. Minimising the solids and food particles going down the drain will decrease the risk of blockage.

How do I choose the right Grease Trap for my application?
The size you need is determined by the amount of water going down your drain. If you have a choice, it is usually best to choose the largest size, giving the most efficient operation and longest cleaning cycle. If you would like help choosing, just let us know and we will be glad to help with your selection.

Can anyone fit it - or do I need a specialist?
We recommend that it is fitted by a qualified plumber or building contractor and should have no problems if your current pipe work is of adequate size, in good condition and is accessible.

How long does it take to get one?
For most of Great Britain, delivery is 1-2 working days, For some of Scotland and the Islands, delivery may take longer. If your order is urgent, let us know and we will do our utmost to satisfy your requirements.


About Fats, Oils & Grease also referred to as FOG

FOG Facts:
Fats, oils, and grease (FOG) clog the sewer lines. Sewage backups and overflows can be the result of grease buildup that can cause property damage, environmental problems, and other health hazards.
FOG gets into the sewers mainly from commercial food preparation establishments that do not have adequate grease control measures in place, such as grease interceptors.
All too often, fats, oils, and grease are washed into the plumbing system, usually through kitchen sinks and floor drains found in food preparation areas. They stick to the inside of sewer pipes both on your property and in the sewer pipes. Over time, FOG builds up and eventually blocks the entire pipe, causing sewage backups and overflows.


To your business: As your sewer pipes back up, the sewage and food particles that accumulate can attract insects and other vermin, cause unpleasant odors, and could create health hazards. Property damage can also result from sewage backups and lead to expensive cleanup and plumbing repairs. Health code violations or closures can greatly impact your business.
To the Environment: Clogged sewers can lead to overflows. As sewage overflows onto streets, it enters the storm drain system and is carried to our local creeks and beaches, creating health risks for swimmers, fish and plant life.
To the County: Increased sewer blockages and overflows lead to costly maintenance and can result in severe fines from county regulatory agencies or water boards. This can increase your sewer fees.

What is FOG and what is the FOG control program?
FOG stands for Fats, Oils and Grease. FOG is animal and vegetable fats, oils and greases as extracted from a wastewater sample by select solvents in a laboratory. Fats, oils and greases are natural by-products of the cooking and food preparation process.

Why shouldn't FOG go down the drain?
When FOG is released into the sewer lines in any amounts, it poses a serious threat to the County's sanitary sewer collection system's ability to remove waste from our community. FOG sticks to the sides of pipes decreasing the pipe's capacity and eventually blocking the pipe entirely. This requires our sewer piping to be cleaned more often and equipment replacement due to grease related damages.

What are the sources of FOG? Who produces FOG?
Common sources of FOG include meat fats, dairy products, food scraps, cooking oils, baked goods, sauces, dressings, sandwich spreads, gravies, marinades, dairy products, shortening, lard, butter and margarine. FOG is produced by restaurants, cafeterias, delis, bakeries, day cares, assisted living, social halls and residential homeowners – basically, anyone who deals with food, especially while cooking.

Why is the issue of SSOs (Sanitary Sewer Overflows) important?
Overflowing sewers release bacteria, viruses and other pathogens that may be hazardous to human health. The sewage may be released into your business or home, or into our waterways, streets and parks. SSOs are unpleasant and expensive to clean up, and if they occur on your property, it is you, the property owner, who is responsible for the clean-up. Having an SSO occur in your establishment may also lower the number of customers.
If the County is responsible for a clean-up, manpower and money are wasted on something that could have been avoided. The costs associated with SSOs are not limited to the Public Utilities clean up costs of containment, removal, and disposal of contaminated materials, emergency line cleaning, disinfectants, sampling and testing, record keeping and documentation, public notification, and EPA & MCWS enforcement actions. The non-direct costs may include media related costs, property damages, public relations, insurance, worker and public exposure to untreated wastewater (pathogens and viruses) and decreased tourism. These costs will, most likely, trickle down into customers' sewer bills.

What do I do with the oil used in deep fryers?
If you are using deep fryers in your establishment, contact a rendering company to provide a bin or barrel for regular pick up.

What is the difference between yellow grease and brown grease?
Brown grease means floatable fats, oils, greases and settled solids that are recovered from grease control devices. Brown Grease is composed of floatable FOG and settled solids recovered from grease traps and interceptors. Brown grease is difficult to reuse. The greasy content of the interceptor is known as "brown" grease and is generally disposed at a wastewater treatment facility but may become part of renewable energy sources in the future.
Yellow grease means fats, oils, and greases that have not been in contact or contaminated with other sources (water, wastewater, solid waste, etc). An example of yellow grease is fryer oil, which can be recycled into products such as animal feed, cosmetics and alternative fuel. Yellow grease is also referred to as renderable FOG.

Should I use large quantities of detergent to wash grease down the drain?
Products such as detergents that claim to dissolve grease may pass the grease down the pipeline and cause problems elsewhere. In short, you remove it from your immediate vicinity only to help create a larger problem downstream.

Should I use additives to wash grease down the drain?
Additives are generally prohibited, as many tend to pass grease down the pipeline and cause problems elsewhere.

Still got a question? Please phone us on 01386 832205 and we will be happy to assist further.