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Grease traps: a legal requirement full of opportunity

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Reasons to integrate your grease trap with a food waste management system.

Rules requiring more work and higher costs are rarely welcomed with enthusiasm in the food service industry – and grease traps are no exception. So it is all the more important to familiarise yourself with the options in order to get the most out of your investment. Jürgen von Borzestowski knows his way around grease traps like the back of his hand. He has been on the Committee for Standardisation of grease traps for 20 years and is a registered expert as per DIN 4040-100, giving him a firm connection to on-the-ground industry. He is also Head of Engineering and Development at specialist food waste management company Meiko Green, so he recognises the opportunities in combining grease traps and food waste management.

Mr von Borzestowski, grease traps are an expensive requirement in food service. Why are they needed?

Well, you may remember news reports of the fatbergs in London's sewers. One of them weighed 130 tonnes and was 200 m long. The newspapers christened it ‘Fat the Ripper’ and it took months to remove it. It sounds like a funny curiosity but it is actually a very serious problem. Waste water from kitchens contains a percentage of animal and plant fats that build up in pipe work, causing blockages. It also sets in motion biochemical reactions that produce biogenic sulphuric acid leading to severe corrosion damage to the sewers themselves. Sewers are public infrastructure, so there is a remit for legislators to act. Local government bodies who deal with municipal drainage therefore require the use of grease traps in commercial enterprises. This applies to the food service, food processing and communal catering industries.

That is a diverse group of businesses. Are the types of system available equally diverse?

The right size and setup of system are the key factors here. There are several factors to consider, like the number of pieces of equipment producing waste water in a given kitchen – cauldrons, combi-steamers, dishwashing machines, etc. – as well as things like waste water temperature. Grease traps separate solids, plant and animal fats, and oils from the waste water using the differences in density. The separated substances are caught in a grease collector and stored in the sludge trap until the required emptying date.

Grease traps must generally be emptied every two to four weeks by a specialist service provider, who will take the contents to a processing facility. These full waste disposal companies who deal with grease traps dilute the fat and solid sludge with the waste water, a much larger volume, before emptying the collector and then separating it again at their destination. This is the industry-standard process but it entails significant costs and is not especially sustainable.

We're talking about waste disposal costs?

Exactly. You can't avoid spending money on a grease trap but you can choose which one, and that will determine the level of future costs over several years. Having your grease trap emptied at least once a month means extra journeys and unnecessary CO2 emissions, not to mention the required refilling of the grease trap using fresh water. Being able to empty the grease trap less frequently also reduces exposure to the smell of the tanker during draining. The smell of a grease trap will put diners off their food – anyone who knows the odour will know how awful it is for customers and employees alike. Any meal is suddenly over when the tanker arrives.

Aside from the smell, if these systems generally work the same, how can business owners reduce their costs?

The process I have described is how it works in around nine out of ten businesses, where full waste disposal companies are used. But there is an alternative: partial waste disposal. Instead of a company coming every two to four weeks to empty the full contents combined, these system simply remove the fats, oil and sludge as needed. Depending on the size of the business, this may be every day or a few times a week. That is why Meiko Green has integrated a partial waste disposal module called ‘Connect’ into their closed waste management system. This makes the grease trap a cornerstone of food waste management, as part of a system that already reduces operating costs.

What is the advantage of integrating the grease trap requirement into a food waste management system?

Leftovers and organic kitchen waste are discarded into an infeed station in the kitchen and fed through a pipe system into a tank where the waste can be stored for months with no need for chilling. The ‘Connect’ grease trap is part of this system and oil, fat and organic sludge – energy-rich resources – are fed into the same tank. This creates a resource cycle, allowing the operator to exploit every advantage available without paying a penny more than necessary. This works equally well with pump- or vacuum-driven food waste treatment systems. Several successful projects around the world are great examples of this, from Traube Tonbach hotel and Düsseldorf student union in Germany to the Jeju Dream Tower Grand Hyatt in South Korea. Of course, existing partial waste disposal systems can be integrated into the waste system as a retrofit.

Can you put numbers to the savings you have mentioned?

You have to take the full picture into account to do that. You see, the savings come through a combination of several individual costs across the year. Combining grease trap and waste system results in a whole range of advantages: no rent or energy bills for chilled waste storage space, fewer waste collections, no cross contamination between waste bins, large savings on worker hours, streamlined and ergonomic work processes and more. Meiko Green customers report saving enough money to pay for the system in three to seven years, going on to make pure savings after that point. Integrating the Connect grease trap maximises these savings. Plus, the full system then comes from one supplier, ensuring the best possible compatibility and minimising response times. The cost drivers mentioned here are completely unnecessary today and come with other disadvantages, too. So whilst we can't do away with the cost of a grease trap, we can do away with additional costs over many years to come.