Independent Restaurants & the Cost of FOGs

What are FOGs?

FOGs – fats, oils, and grease – are a common byproduct of commercial kitchens and food-processing facilities nationwide. Many of these substances may seem harmless in small amounts; however, they tend to solidify and stick together in the sewer system, which means even small trickles of grease can create big problems for the community. Here are some common FOGs found in wastewater from kitchens and food-processing facilities:

What is a "fatberg," anyway?

Once FOGs enter the sewer, they float to the top of the stream and begin sticking to each other until large clumps of grease and fat are floating around underground. Along the way, these sticky, oily masses pick up other floating debris, such as leaves, sticks, paper trash, and sanitary napkins. The worst offenders are flushable wipes, which, despite what their misnomer implies, don't dissolve once they're flushed down the toilet and enter the waste stream.¹ The wipes' resilient materials act as strengthening and binding agents, enabling debris to collect in larger clumps as additional wastewater moves past. These masses of mixed fat, trash, and excrement are colloquially known as "fatbergs," and they can wreak havoc on a city's sewer system, as well as its wastewater treatment plants.²

According to an EPA report on combined sewer overflows, "grease from restaurants, homes, and industrial sources are the most common cause of reported blockages."³ It's not just that grease often solidifies at ambient temperatures or that it's sticky and tends to bind loose, floating debris together like glue. FOGs also undergo saponification, a chemical process triggered when the congealed fats are exposed to sources of calcium – the very concrete of which many sewers are made, for example.⁴

Through this process, the already intimidating clogs of fat are converted into a soap-like substance that, once hardened, can be as difficult to break up and remove as concrete.⁵ Over time, these hardened deposits build up, choking off the flow of material and causing sewage runoff to back up and potentially overflow. Removing these fatbergs once they've formed can cost a city millions.

In light of such serious consequences, it's no surprise that many cities are enacting or updating grease disposal regulations.

Back to top

FOG Separation & Disposal

Fatbergs aside, improper disposal and processing of FOGs can lead to hefty fines, expensive plumbing repairs, sewage overflows, and restaurant closures.

Knoxville Utilities Board (KUB), for example, enforces a ruling that restaurants using automatic commercial dishwashers can no longer plumb through a grease trap. Instead, they must install a minimum 1,000-gallon grease interceptor so big, it typically has to go outside, or even below the restaurant.

If the building a restaurant is in doesn't easily accommodate this addition – it may be too old, or too small, or lack a basement or a couple of manholes and a baffle wall – then business owners might have to dig out space underground for the interceptor. That can get pricey, sometimes exceeding $15,000⁶, and the whole tab goes to the dining establishment, even if they don't own the building in which they operate. If the cost doesn't fatally choke the business, making the structural improvement can seem like pouring tens of thousands of dollars down the drain.

On top of these hefty upfront costs, businesses also must have their grease tanks pumped out and cleaned regularly to ensure they're operating as intended.⁷ This means a restaurant must locate a reliable grease removal company that can be trusted to handle and process FOGs in a legal manner and then contract the company's services on an ongoing basis. Over time, these maintenance costs add up, leaving many restaurants resistant to making the change.

Restaurant owners and operators who don't want to eat the cost (or can't afford to) are stuck washing their dishes by hand – and that's not always the most efficient option for a dining hotspot.

Back to top

Grease Trap vs. Grease Interceptor: What's the Difference?

Both grease traps and grease interceptors serve a similar purpose, and many people use the two terms interchangeably, so understanding the difference can be confusing. When it comes to remaining compliant with local regulations and ensuring your establishment disposes of grease legally, there's no room for error. To shed some light on this somewhat slippery subject, we'll cover grease-separating units and their best uses below.

Although they're both types of FOG-removal units, the primary difference between a grease trap and a grease interceptor is its size.

Most grease traps are small enough to be installed inside a commercial kitchen, usually below the sink, and can hold 200 gallons of wastewater or less. Grease interceptors, on the other hand, may hold anywhere from 500 gallons to more than 1,500 of gallons of wastewater and must be installed underground, typically outside or below the venue.⁸

How does a grease trap work?

Grease traps and grease interceptors work the same way but at differences scales. FOG-filled wastewater can't be drained directly into municipal sewage lines. Instead, it first drains into a tank where liquid waste, solids, and FOGs separate.⁹ As FOGs harden, they solidify and float to the top of the tank, while other solids, such as food scraps and dirt, settle to the bottom. The tank is designed so that only separated wastewater flows out and into city sewage lines, while FOGs remain trapped in the tank. Like a septic tank, the grease trap/interceptor tank must be pumped out periodically to remove the collected FOGs for processing and disposal.

Who needs a grease interceptor?

Any facilities that dispose of wastewater containing fats, oils, or grease into the city sewage system need to install FOG-removal units. The unit's size, as well as where it's located and how it's installed, typically are determined by the amount of wastewater produced by the facility, as well as city, county, or state ordinances.¹⁰ Always check health department and EPA regulations pertaining to grease interceptors prior to purchasing or installing any FOG-removal unit.

What do Fatbergs Have to do with My Restaurant?

Grease in the sewage system has been a universal problem in urban areas for several years and has only been exacerbated since the proliferation of "flushable" wipes and cleaning products first began.

According to New York City's 2013 State of the Sewers report, over 60 percent of its 15,000 sewer backups were caused by grease.¹¹ The City of London famously foundered on a massive grease blockage in 2013, and in May of 2021, an even bigger fatberg weighing 330 tons and stretching over half a mile in length was discovered in neighboring Birmingham.¹² According to Thames Water (which is responsible for operating the London sewer system), the company spends over $1 million each month on breaking up and removing these massive clogs.¹³

Other newsworthy fatbergs have appeared in Boston, Des Moines, Charleston, and Seattle, just to name a few.

Knoxville's FOG issues, then, are typical of growing cities, and KUB, like so many other utility companies, is simply following the federally mandated grease-control program set by the Environmental Protection Agency¹⁴ to reduce grease blockages and sewer overflows. Most restaurateurs have no quibble with that logic; who, after all, hates a grease backup more than the dishwashing staff?

Compliance with local regulations aside, it's in all restaurants' best interests to keep their grease moving and adequately disposed of in up-to-date equipment since spoiled-food odors and sewage overflows have the power to kill a business all by themselves.

Back to top

Grease Trap Safety & Your Business

The rise of grease interceptor regulation and need for ever-larger separating tanks has helped resolve one set of problems, but unsecured grease trap lids can be potentially dangerous. In nearly every incident of a grease trap causing injury or death, the grease trap's lid had not been bolted back down after the tank was cleaned and serviced. There were no barriers or warning signs of any kind, and restaurant owners hadn't installed any safety netting or other device to prevent children and small animals from falling down the hole.

Although such tragedies are rare, they can be prevented with a few simple safety measures. Some of the proposed safety measures that have been included in grease trap legislation so far include the following:

• Heavy-duty metal lids made of cast iron or other similar material capable of supporting as much as 250 pounds of weight
• Keyed locking mechanisms that can be opened only by authorized staff members
• Barriers placed around any opening that's flush with or less than 18 inches off the ground
• Warning signs posted near the grease tank access hatch
• Secondary safety screens designed to prevent children or small animals from falling down an open shaft if the lid is left unlocked, or is damaged or missing

Many of these safety features can be installed easily at a low cost to the operator, and while many areas don't mandate their use, they can benefit the business and community. Investing in a heavy locking lid can help prevent grease theft and vandalism. Ensuring the tank's lid remains secure and fastened at all times can prevent debris and waste from falling inside the tank, possibly causing clogs or damages that require expensive plumbing and grease trap repair.

When it comes to keeping down costs, fines and repair fees aren't all restaurant owners need to consider. Aside from the stigma of being associated with negative press coverage due to an incident, operators at locations where grease trap deaths have occurred – as well as the companies responsible for designing, assembling, and servicing the tanks – have been slapped with multimillion-dollar lawsuits. In Alabama and New York, new laws mandating locking lids and child safety features have since been enacted, but this type of requirement is still lacking in many states, leaving many restaurant owners in the dark about the dangers (and liabilities) of their grease traps.

Back to top

Grease Interceptors & Your Restaurant

The takeaway for restaurant owners? Grease trap and FOG-disposal laws aren't done changing yet. As an increasing number of municipalities begin to require large, underground grease interceptors, more restaurant owners will be tasked with paying for these units and ensuring they don't pose any danger to employees or the community.

Although they can be expensive, grease interceptors are a great way to prevent FOGs from ending up in your sewer system, ensure your venue remains compliant with local grease disposal laws, and prevent sewage overflows near your business. Fortunately, many simple and affordable safety precautions can be installed alongside your new grease interceptor, so you can also invest in guest and employee safety as you transition from an under-sink to an underground FOG separation tank.

References

1. America's Obsession With Wipes Is Tearing Up Sewer Systems. Bloomberg. Accessed November 2021.
2. What Is a Fatberg? The Gross Grease Giants Threatening Cities. Newsweek. Accessed November 2021.
3. Report to Congress on Impacts and Control of Combined Sewer Overflows and Sanitary Sewer Overflows. Environmental Protection Agency. Accessed November 2021.
4. Fat Turns into Soap in Sewers, Contributes to Overflows. Science Daily. Accessed November 2021.
5. Huge Blobs of Fat and Trash Are Filling the World's Sewers. National Geographic. Accessed November 2021.
6. Grease Trap & Interceptor Installation, Repair, & Maintenance. Grease Management Solutions. Accessed November 2021.
7. Five Must Knows for Kitchen Grease Trap Maintenance. Modern Restaurant Management. Accessed November 2021.
8. Grease Traps vs Grease Interceptors. Service Pumping & Drain Co., Inc. Accessed November 2021.
9. How Grease Traps/interceptors Work. Plumbing Supply. Accessed November 2021.
10. Food Service Establishment Laws on Grease Traps. Small Business Chronicle. Accessed November 2021.
11. Department of Environmental Protection Releases 2013 Sewer Performance Report. NYC Environmental Protection. Accessed November 2021.
12. Giant 300-tonne Fatberg Blocks Birmingham Sewer. BBC News. Accessed November 2021.
13. A 330-ton Fatberg is Clogging an English City's Sewer, and It Won't Move for Weeks. CNN World. Accessed November 2021.
14. Controlling Fats, Oils, and Grease Discharges from Food Service Establishments. U.S. Environmental Protection Agency. Accessed November 2021.