Dealing with the fat of the land

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Fats, oils and grease disposal in commercial kitchens remains a contentious issue.

The catering industry as a whole is having to face up to the issue of fats, oils and grease (FOG) disposal, with regular headline-making stories about fatbergs entering and blocking sewers. But taking the process back up the equipment supply chain, what can suppliers and distributors do to solve FOG problems?

According to Kristian Roberts, marketing manager at Mechline Developments, which produces the GreasePak biological treatment solution and the new BioCeptor grease management system: “The industry as a whole is well aware of the issues caused by FOG (thanks in part by the surge in media attention, from the fatberg on display in the Museum of London, to the televised fatberg autopsy) and despite varying agendas, there is a general consensus that kitchen best practice and training is vital in preventing FOG entering the sewage network.

“However, operators cannot be held entirely responsible for the ‘fatberg’ problem plaguing the UK. As has been reported before, it is wet wipes that make up 93% of the material blocking the sewers, not FOG (Water UK).

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“FOG has been escaping into sewer systems for decades without the same large scale problem. Mechline urges the industry not to use commercial kitchens as a scapegoat for an issue that is exasperated by recent use of non-biodegradable wet wipes and a reduction in sewage maintenance schedules.”

At Environmental Products and Services (EPAS), manufacturer of the GreaseShield grease trap, sales director Gareth O’Neill believes: “Engagement in the industry has to begin with the correct advice on the performance and sizing of grease management systems. Engagement within the industry has to demonstrate effective performance to ensure that the end users’ costs and water companies’ FOG blockage costs are reduced.”

Elsewhere, Kingspan Environmental’s business development director, Europe (sensor and service), James Curran, said on the subject: “In my opinion, there has been wide enough engagement to solve FOG issues; the problem is that all it has been is engagement!

“It’s now time for next steps, and that is why Kingspan is encouraging the industry to come together and drive change for the better. We know and understand the consumer/foodservice equipment (FSE) challenges, and we are focusing our knowledge and expertise around sizing applications accordingly. This then leads to best practice implementation in areas such as design, install, measuring and monitoring, and service and maintenance, ensuring peace of mind for the FSE manufacturer, specifier, end user and water companies.”

While Erik Mul, technical product manager at Aco Building Drainage feels: “Although companies like ACO are in continuous contact with organisations such as British Water, especially though their ‘FOG Forum’ initiative, there needs to be much more engagement across all parts of the industry.

“The key issue is the largely ineffective legislation surrounding grease management. To help drive engagement, we need to agree minimum performance standards and best practice guidelines for the specification of grease management solutions. Organisations such as CESA are attempting to develop clear codes of practice but these will need to be discussed and endorsed by all parties.

“Water companies also need to have more powers to call end users to account. At the moment, water companies understandably prioritise the reduction of water leaks, for which they can be heavily fined, over FOG management.

“There are thankfully some responsible commercial kitchen operators who are actively looking for ways to deal with FOG, but less reputable operators are only subject to minimal fines if they fail to deal with the FOG generated by their premises. Furthermore, time-pressured Environmental Health Officers are understandably focused on issues other than on fats, oils and grease during commercial kitchen inspections.”

Mechline launched its BioCeptor grease management system at the end of last year.

Focusing on the current FOG management guidelines, Mechline’s Roberts underlined: “Through its code of practice, British Water has educated kitchen operators on the various methods of FOG treatment available. It specifies different types of equipment that will assist in reducing FOG entering the sewer and recognises that ‘using more than one equipment system or utilising multiple units of the same equipment will increase the potential to prevent FOG entering the kitchen drains and sewer through separation and treatment’. It is important to continue encouraging operators to make informed decisions on the right solution for their site, instead of indiscriminately applying a specific, potentially unsuitable, option.”

However, EPAS’s O’Neill thinks: “FOG management guidelines are currently generic and do not provide the detailed information on the performance of grease management equipment. Manufacturers’ claims of performance and flow rate are not tested and no demonstration of the performance in terms of the levels of FOG removal is provided. The evidence is demonstrated by the increasing costs incurred by UK water companies in maintaining and cleaning the drain lines and the numbers of reported fatbergs.”

ACO’s Mul underlined: “The current FOG guidelines are neither specific nor consistent. Building Code H does not require strict adherence to a specific standard of grease management solution and is loosely worded. It states that ‘Drainage serving kitchens in commercial hot food premises should be fitted with a grease separator complying with BS EN 1825-1:2004 …or other effective forms of grease removal’. Furthermore, BS EN 1825 is not an adopted standard in the UK.

“British Water has only generic FOG guidelines which give an overview of what grease management options are available but do not provide any real specification guidance to help end users and specifiers determine which grease management system to use. The UK also has no general performance standards for grease management systems and as a result, there is no way for end users and specifiers to evaluate the effectiveness of different systems and assess their pros and cons in different applications.

“This results in customers opting to leave a grease management system out altogether or choose the cheapest solution, which might not be necessarily best/most efficient way of dealing with the FOG issue.”

Kingspan’s Curran agreed with these sentiments, adding: “This is clearly evident with the lack of consumer/FSE awareness around the responsibility to ensure FOG is managed at source.

“There are too many conflicting opinions on best practice solutions which promote one specific manufacturer or design/solution, often leading to undersized equipment for applications.”

In terms of specific standards and accreditations for FOG management equipment, Roberts commented: “There is no ‘standard’ as such in the UK for grease management. The only referenced standard is the BS EN 1825, which is spawned out of an old DIN (German) standard and directed at large in-ground grease separators. Often operators think that standalone grease traps are the only answer, and further still that bigger is better, but this is not the case. Size does not determine efficiency or effectiveness.

“The most authoritative and accredited standards in the testing and qualification of internal interceptors are ASME and PDI. Both are internationally recognised and cited by many government agencies and in plumbing codes.

ACO’s Eric Mul believes the key issue is ‘ineffective’ legislation surrounding grease management.

“In 2018, at the FOG conference organised by British Water and held at Cranfield University, several water companies agreed that there was no recognised UK standard for internal grease traps, and the starting point for accredited traps was ASME [from the USA] as a minimum.”

Also acknowledging that the UK has no standard for grease management, O’Neill pointed out: “Grease interceptor manufacturers claim their equipment are designed in accordance with EN1825 and do not have the certifications to demonstrate the claims. In addition the testing media for EN1825 is marine diesel oil which is designed to float on water and is therefore not a suitable test for FOG removal.

“There are a limited number of grease recovery units in the UK that are certified and accredited to the North American standards of PDI-G101, ASME 3 for grease traps and ASME 4 for grease recovery units who can demonstrate the grease retention rates and performance based on correctly sized flow rates. All UK grease management equipment should be flow rate and performance tested.”

Curran also underlined: “We are meant to adhere to EN1825 guidelines but I often see manufacturers refer to PD11, which is the American standard for best practice. Again, more education is required to understand what would be the best solution for the application, and how we size this accordingly.

“More has also to be done to guide the consumer around pollution prevention, and a British Standard specification document has to be implemented with clear and transparent sizing criteria guidelines.”

Mul, too, believes: “There are some significant issues with the way testing is conducted and the current standards are not rigorous enough. They simply don’t correspond with the reality of a commercial kitchen environment.

“The biggest issue is the use of influent medium. Waste water content is unique to every kitchen but mostly comprises a mixture of animal fat, vegetable oil and food particles with a range of densities. However US standard PDI-G101, for example, tests products using lard (at test temperatures of 70°C) even though waste water in most commercial kitchens is typically 35-40°C – a temperature at which lard solidifies.

Kingspan’s SmartServe Grease Management System incorporates Trapzilla Grease Trap which is claimed to capture 95% of grease waste.

“In contrast, BS EN 1825 uses diesel oil in tests. Diesel has a density of 0.85 whereas vegetable oil, for example, has a density of up to 0.97, making it much harder to separate out. A better option would be to test products using a mix of vegetable oil and animal fat so their performance can be properly evaluated in conditions which are more similar to those which commercial kitchen operators are likely to encounter.”

He concluded: “Tests for all three standards are also weighted to maximum flow rates when in reality this would only occur in a grease management system three or four times in one day and for a short period of time. While inlet testing temperatures do not relate to the waste water inlet temperatures typically experienced in a commercial kitchen.

“Not only are we learning about waste water flow patterns, but also which elements within the waste water that are harmful to either health or to the sewer system.”

Associated solutions

Supplier association CESA has been at the forefront of solving FOG issues in the catering industry, with chair Glenn Roberts reporting: “Currently, FOG management guidelines are confusing because different water companies and manufacturers give differing advice.

“It was because of this that CESA prepared the British Water FOG Guidance document. It highlights the responsibility for foodservice sites not to block the sewer with FOG outputs. The guide features the roles and operating principles of grease traps, grease removal units and enzyme treatment systems. Each has a critical part to play in managing treatment.”

In terms of current accreditation systems for FOG management equipment, he detailed: “There are North American standards but these have no validity in the UK. Rather, they are used as a reference for products. There is EN1825 which relates primarily to grease traps, but the test methodology uses diesel oil and water as the test medium. CESA is working on a project to develop a test methodology for grease removal units that relates to our industry.”

With the Grease Contractors’ Association in its infancy, Roberts feels that if it is able to deliver consistent, clear advice then it will help solve FOG issues. But for industry engagement overall, he revealed that CESA is trying to improve the situation.

“The CESA FOG group is developing a document that would help operators, designers, consultants and installers to better understand the operational characteristics of fats and grease management and removal technologies. It will include an evaluation of the standards that exist around the world, in order to try to recognise any shortcomings and to propose a document that is fit for purpose. The document would also effectively validate the performance of products, so that informed decisions can be made by buyers and specifiers.”

Tags : acoCESAepasFOGkingspan environmentalMechline
Clare Nicholls

The author Clare Nicholls


  1. Good points here, but if dealers/specifiers chose the modern grease free grills with no fat tray like Synergy, that in itself would help alleviate fatbergs. The equipment is there – just needs action not words, and promotes British technology across the world in this key environmental field.

  2. Fatbergs are definitely hard to remove from your Grease Traps. Using good chemicals like rtb 740 would help you with maintaining your Grease Traps.


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