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Icebergs of Fat, Oil, and Grease Are Growing in the Sewers Beneath Our Feet. Here's Why.

Thanks to wasteful sanitation habits, so-called "fatbergs" have increased in recent years—costing taxpayers in cities around the world a small fortune.
Vince Minney works in the sewers in London on December 11th, 2014, fighting against the fatbergs clogging the system.

Vince Minney works in the sewers in London on December 11th, 2014, fighting against the fatbergs clogging the system. Massive fatbergs have recently emerged in locales such as London, New York City, Baltimore, South Carolina, Michigan, and New Jersey.

A specter is haunting Europe—and the United States, and the rest of the developed world. It lurks beneath our streets, slinking along with oily modesty as it searches out hospitable corners of our cities. When it gains a foothold, it grows rapidly and calcifies to formidable strength, disrupting civic flows and belching furiously. And this monster, it comes from us. The fatberg.

Fatbergs are giant lumps of fat, oil, and grease that congeal around a lattice of wet wipes, condoms, and other plasticky sanitary products into unholy blockages that clog, and sometimes burst, sewer pipes around the world. At least one is forming in your city right now: Massive fatbergs have recently emerged in locales such as London, New York City, Baltimore, South Carolina, Michigan, New Jersey. Most of them don't even make the news. Last week, a fatberg was discovered in the sewers of a tiny, coastal town in Southwestern England that stretched for 210 feet. Picture two NBA-length basketball courts end to end covered in a writhing, gray mass of candle-like material fit to light Hell. It was longer than that, and more horrible.

Which is really nothing on the fatberg scale: 2017's Whitechapel Fatberg was 130 tons, a football field long, the size of 11 double-decker buses. When the Museum of London displayed a chunk of it as an exhibit (Fatberg!), a caption read: "The size and foulness of fatbergs makes them impossible to ignore and remind us of our failings."

Despite their plentiful bounty of fatty sewage, fatbergs also eat up huge portions of public funds. They devoured $5 million of New York City's public coffers in 2013 and $18 million over five years preceding 2016. London spends about £12 million (or $15.5 million) annually on them, Thames Water, the city's utility company, told the Guardian. According to the Environmental Protection Agency, 65 percent of sewage spills are fatberg-inflicted.

The term fatberg—An iceberg of fat!—added to the Oxford English Dictionary in 2015, was coined by London's "flushers," workers employed by the city's privatized water company in what Curran called the "cold-faced sludgery of trying to clean up the mess." Though the term appeared once in a Birmingham, United Kingdom, newspaper in 2008, it mostly remained flusher slang until a 15-ton fatberg (then Britain's largest fatberg, a record that has since been annihilated several times over) was discovered and removed from a London sewer in 2013, under much media scrutiny.

How do they get so supersized? The fat, oil, and grease (FOG, in waste treatment industry parlance) comes primarily from kitchens—poured down the drain after cooking—as well as from undigested remnants of food that have already traveled through the pipes of the human body. The baby wipes, tampons, condoms, and make-up removers come inadvisably flushed down toilets: the detritus of contemporary hygiene and beautification jettisoned to watery depths without consideration. A fatberg's strength ultimately comes from its structure. Fatbergs are composed primarily of long-chain fatty acids, which—like wet wipes—repel water, and are too complex for most microorganisms to decompose, Asha Srinivasan, a fatberg researcher at the University of British Columbia told me.

"It's a bit like bricks and mortar combining," says Tom Curran, a fatberg expert and professor of biosystems and food engineering at University College Dublin. "You have the solid matrix of the wet wipes, which binds to the fats, solids, and grease, a mortar-like combination. So it makes it very difficult to break down."

Though fatberg occurrences and awareness have increased in recent years, flushers have been cleaning up the clogged arteries of major cities for generations. In London, the Guardian reports, many flushers come from families of flushers, the work tradition passed down from father to son to grandson, as is common with stonemasons and undertakers. Many of the current flushers are third generation, and 30 years into their work. But recent trends have toughened the workload. Previously, according to the Guardian, "there was a good deal of job satisfaction in the work; it had a nice psychological trajectory: they started a shift with a blockage, and ended it with the sewer flowing freely." Now the fatbergs are constant. (They occur pretty much everywhere with dense populations and modernized sewers, but they are especially prolific in the United Kingdom, which Curran called "ground zero for fatbergs.")

Why has it gotten so bad? Increasing urbanization is a major cause, according to Curran. Larger numbers of people living close together at higher rates means city sewers are flowing with ever-more waste—including more fats and flushed sanitary products. "The United Nations predicts that, by 2050, two-thirds of the world's population is going to be living in cities," Curran says. "So, the problem's going to get worse unless you have programs where you're preemptively dealing with the blockages in terms of fats, solids, and grease." Restaurants in city centers tend to be the most significant culprits of improper grease drainage, especially during economic booms when eating out is popular. In Dublin, Curran helped implement strict restaurant grease regulations that reduced fatbergs from 1,000 per year to 50.

The wet-wipe industry has also expanded in recent decades, leading to a spike in flushed plastics and fatberg fodder. Curran says that the wipe industry has expanded by marketing hyper-niche wipes to every category of consumer. "You have wipes for all segments of the market," Curran said, pointing to Dude Wipes, a product with endorsements from UFC fighters and NFL players, whose website describes it as "dingleberry destroying ... to keep you stank free." Many of these wipes misleadingly market themselves as "flushable," which almost never means that the sewers can handle them, according to Curran—who believes himself to have personally caused a local sewage back-up of purportedly flushable baby wipes when his first child was born. (This was before he began studying fatbergs; he'd never make the mistake now.)

The best defense against fatbergs is grease traps: apparatuses installed under restaurant sinks that capture oils and fats before they go down the drain. Countries and cities with the strongest grease trap regulations tend to fare best—the U.K.'s loose regulations are a primary exacerbant of their outsize fatberg problem, according to Curran. Other cities have seen fatberg reduction following education campaigns to encourage composting and convince people not to pour grease down their drains.

Currently, fatbergs are demolished with blunt force, using drills, chains, pressured hoses, and other tools to break them up. "We have lots of weapons at our disposal," a flusher named Alex Saunders told the Guardian, "but sometimes, as with the Whitechapel one, it is so impacted that a lot of it is the teams going down and chiselling away by hand." The fatberg pieces are them removed by hand, or, if they have been liquified, sucked up to the surface by a vacuum.

At least one company, Argent Energy, converts removed fatbergs into biodiesel fuel, a process that is highly energy-intensive. Srinivasan's team at the University of British Columbia has been developing a process that may allow biofuels to be created from these fats at a much lower energy cost, but Curran says the best approach is always prevention. Removing and treating FOG that doesn't turn into fatbergs accounts for a quarter of the costs incurred by sewage treatment plants. "The first rule of waste management is to prevent the problem, rather than trying to eat up all the fats, solids, and grease afterward," he says. "You're better off trapping the used cooking oil and grease and making bioenergy out of it, rather than letting it go down the sewer and having to deal with blocks of fatbergs."

But if prevention fails, fatbergs, dirty as they are, can also clean—or at least produce soap. Saponification, the soap-making process, occurs when an oil is mixed with an alkaline material—usually lye in commercial soap. "Sewage is very complex and heterogeneous in nature, so it might have alkaline parts in it that can cause saponification," Srinivasan says.

So, in theory, could a fatberg clean itself up, I wondered? "It is possible," she said, kindly humoring me.