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Fatbergs! How Bad Are They and What Can We Do About Them?

October 7, 2013

In case you missed it, the word fatberg is officially part of the English language. A fatberg, so named by the water company that discovered the thing, is a sewer-clogging monster of fat, grease, and cleaning products. In August, Thames Water unclogged a 33,000-pound beast from the London sewer system. The discovery makes one wonder about the terrifying fatbergs that lurk beneath American cities, and what we can do about them.

from dailymail.co.uk

Where do fatbergs come from?

According to Thames Water, we are all responsible for their creation. Fats, oils, and grease (or FOG) – often mindlessly poured down drains – combines with cleaning products, especially non-degradable wet-wipes. “Fatberg creation is a vicious cycle,” Thames Water media relations manager Simon Evans said in  Atlantic Cities. “Fat clings to wipes, wipes cling to the fat.”

It’s tempting to take a perverse pride in uncovering a world record fatberg, but Thames Water representatives warn that they discovered the blockage just in time to avert city-wide disaster. “The sewer was almost completely clogged,” Gordon Hailwood, the waste contracts supervisor for Thames Water told The Guardian. “If we hadn’t discovered it in time, raw sewage could have started spurting out of manholes across the whole of Kingston. It was so big it damaged the sewer and repairs will take up to six weeks.”

Though London avoided a sewage explosion and a public health disaster, it doesn’t avoid the costs associated with cleaning fatty deposits from its sewer systems. The Guardian notes that Thames Water spends about $1.5 million monthly blasting out sewage blockages. This cost that gets passed on to taxpayers.

American cities and citizens experience similar costs. San Francisco utilities estimate that unclogging pipes costs the city $3.5 million per year. A 2011 SeattlePI article suggests that although Seattle’s blockages aren’t in the same ballpark, an estimated 544,000 gallons of grease slip down Seattle drains each month. To put this in perspective, that’s about seven swimming pools of grease, each month. Between 2003 and 2009, the city responded to 147 sewage blockages (not counting private sewage system blockages). Each response costs the city about $1,500, according Seattle Public Utilities, or about $220,000 total.

Frank Dick, Industrial Pretreatment Coordinator for the City of Vancouver, WA, has studied the cost that wet wipes alone levy on city services and rate-payers. He suggests that wrongly flushed wipes cost Vancouver residents a total of $225,000 per year. Dick factors in costs for sewer maintenance, increased electricity pumping, and replacing gummy wastewater treatment pumps.

Both businesses and citizens are to blame for clogged sewers. In the SeattlePI article, Ryean-Marie Tuomisto – coordinator of the city of Kirkland’s fats, oils and grease program – says the main culprit is us. “Most of the grease build-up that comes into our system is from your basic dishwashing,” Tuomisto said. “The slow discharge into the system accumulates and causes problems.” We dispose of too much food scraps, fats, and grease down our sink instead of in the garbage or compost. Grease gloms onto wipes, causing fatbergs.

Because grease is technically illegal to dump down drains, most restaurants dispose of used cooking oils in grease bins, or “grease traps,” which catch FOG before it washes down pipes with the dishwater. The grease can then be collected and sent to landfills or converted to biodiesel. Some restaurants are required to install grease traps. But many older restaurants, which opened before plumbing code required pre-treatment devices, may not use them. According to 2011 SPU estimates, of 2,600 “food service establishments” – which include bakeries, groceries and restaurants that seat more than 12 people – only 1,000 have pre-treatment devices.

What Can We as Consumers Do?

A big part of the FOG problem is an uninformed or misinformed public. Educational campaigns can partly address wrongful public disposal of grease and wipes. Public utilities are trying to gather momentum around campaigns that target schools and children. In many school districts, for example, students learn about “grease monsters” and how to prevent them. United Utilities, a British company, has a campy message for flushers of any age:

So what can we flush? To put it simply: “pee, poop, and toilet paper,” says Bobbi Wallace of Vancouver Public Utilities. “That’s all our sewer systems were designed to handle.”

Changing marketing practices might also help change the public’s behavior. The American Public Works Association, along with other associations of public utilities, is fighting the false labeling of wipes. In stores throughout the country, wet-wipes are marketed as more convenient, durable, and clean than toilet paper. Many of these products proclaim “flushable” on their labels. But “flushable” is a grave misnomer.

from walmart.com

“Wipes are labeled as ‘flushable’ simply because it’s possible for them to be flushed down the hole of the toilet,” Wallace of Vancouver Public said. “But they’re not flushable. Once they’re in sewage pipes they don’t break down. They cause all types of problems.” According to Wallace, wipes both clog sewage pipes and jam wastewater treatment pumps. The Federal Trade Commission is currently reviewing the appropriate definition and marketing of wipes labeled as “flushable.” Costco recently became the first U.S. store to put non-flush logos on its non-dispersible (meaning non-coming-apart) wipes. The superstore, however, requires this logo on only the back side of wipe packages. The fronts of its packages – the side most consumers bother to read – often say “Flushable” in fat letters. Such mislabeling means that the American superstores most conscious of the wipes problem are not doing much to address it.


What Can Businesses Do?

Opportunities increasingly exist for FOG producers and haulers to benefit from preventing grease pollution. In 2011, Portland, Oregon started a Preferred Pumper Plan to promote removing FOG at its source, in the grease traps beneath restaurants, before the stuff causes “municipal heart attacks” by entering sewers. The plan standardizes the collection of FOG to ensure grease traps are cleaned correctly and frequently. Pumpers registered with the program agree to follow criteria that allows for their performance to be monitored. FOG generators that join the program benefit because they don’t face the responsibility of cleaning their own traps. This responsibility falls on pumping companies. The city of Seattle is developing a similar plan to incentivize grease collection.

In areas with established biodiesel markets, grease collection companies can get paid for more than performing disposal services. These companies can sell grease to biodiesel plants. Most biodiesel plants currently accept yellow grease, or used liquid frying oils. In the Northwest, the market for grease is growing. A few Washington companies, such as Standard Biodiesel in Arlington, WA, currently pay restaurants for their yellow grease. A Salem, Oregon plant, Sequential Pacific Biodiesel, which specializes in biodiesel production from cooking oils, recently expanded to produce 5 million gallons of fuel per year.

The next frontier of biodiesel technology involves transforming brown grease, the gunkiest grease found in grease traps, into usable fuel. Most brown grease is deposited in landfills. But better options are cropping up. A few wastewater treatment plants in Northwest cities inject brown grease into anaerobic bio-digestors to produce biogas, or methane. The City of Gresham, OR, uses digestors fed with brown grease to produce enough electricity to cover half the plant’s energy needs. This re-use of waste significantly reduces the city’s energy costs considering the hefty energy load required to run a wastewater treatment plant. Gresham’s plant, for example, requires about the same energy it takes to power 600 homes per year. (Gresham is aiming for the complete energy independence of its plant by 2014, an achievement that would save half a million dollars in energy costs per year.) Clean Water Services is working to install systems like Gresham’s at other wastewater treatment plants throughout the state.

Another re-use option involves transforming brown grease to biodiesel. Unlike its light-bodied cousin yellow grease (primarily vegetable oil), brown grease requires more pre-treatment before yielding usable biodiesel. A few companies, however, have demonstrated the feasibility of re-using brown grease as fuel. Pacific Biodiesel Technologies, for example, runs a successful brown grease to biodiesel program in Hawaii. It processes brown grease into a few different valuable commodities, among them compostable solids and boiler fuel, which is used as a replacement for bunker oil (often fairly filthy stuff) used in power plants, canneries, and mills.

Whether created from yellow or brown grease, biodiesel benefits more than just those businesses involved in buying and selling it. The fuel benefits environmental and public health. Burning biodiesel is much cleaner than burning fossil fuels. According to the EPA, biodiesel decreases greenhouse gas emissions by 57 to 86% when compared to petroleum diesel. Also, burned biodiesel produces far less harmful air pollutants, like sulfur dioxide, than fossil fuels. And, as a non-toxic or biodegradable substance, biodiesel poses less threat in stormwater than the toxins that enter our water bodies from petroleum.


Solutions to FOG issues, like fatbergs, exist. But they need public and political willpower to take effect. Business-motivated solutions require collaborative partnerships between private business (restaurants, biodiesel plants) and public utilities. Restaurants and FOG haulers can be motivated to re-use grease if re-use is viable and profitable. So the question is: how can we make re-using grease easier, more effective, and more profitable?


* The newly-formed Western States Alliance is a program of PPRC’s that looks for opportunities to improve service to our communities as they deal with aging infrastructure and the burdens that FOG and other contaminants place on their water treatment system. In addition to working to standardize reporting efforts for western states, PPRC is working to enhance the opportunities for education, training, and networking between different stakeholders in FOG. We believe that such collaboration can both prevent grease related sewer blockages while opening innovative business opportunities.


Additional Resources


– Cyrus Philbrick

Communications Manager

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