Trash cans are a ubiquitous, and malodorous, fact of urban life, but a few dozen cities around the world are experimenting with eliminating them.
In their place, local governments are installing chutes which connect to an underground system of pneumatic tubes that use high-pressure air to whoosh garbage away to a handful of centralized collection points.
Envac, the Swedish company that controls most of the trash-tube market, says its infrastructure beautifies city streets, curbs carbon emissions and traffic snarls caused by garbage trucks, and keeps the rats away. The systems can even keep track of how much waste individual households and businesses generate, allowing local governments to tax them accordingly.
Envac’s pneumatic trash systems are now the default infrastructure for new developments in 44 cities, from Seoul to Doha to Barcelona. This alternative approach to collecting waste could lead those towns to a cleaner, greener future—but it remains to be seen whether budget constraints and logistical headaches will keep the technology from expanding beyond the wealthy cities of Europe and Asia.
The technology underlying vacuum waste systems isn’t new. As early as the 1890s, cities like Philadelphia and New York were using miles of underground pneumatic tubes to shunt mail around town. Envac installed the world’s first air-powered waste system in a hospital outside Stockholm in 1961, and began installing tubes for neighborhood trash pickup in parts of Stockholm in the 1970s.
But Jonas Dahllöf, who heads the planning and development department for Stockholm’s waste management authority, said the city recently reached a turning point. For decades, Envac installed its systems on an ad hoc basis, wherever private developers were willing to pay for them. But as of last year, the city has taken on responsibility for building and maintaining the pipe systems, and pledged to install them in new developments.
“Our vision is that underground waste collection will become a natural part of the city’s infrastructure—as natural as water, sewage, and electricity,” said Envac CEO Joakim Karlsson.
Already, there are over 100 Envac systems in Stockholm serving about 120,000 households—roughly 20% of the city. In the neighborhoods with vacuum tubes, residents walk their trash to a set of chutes, which may be built into their apartment buildings or on the street near their doors. Food waste goes down one chute, destined for a facility that turns it into biofuel. Recyclables go down another. And the third is for mixed waste that’ll wind up in an incinerator.
Every so often, a trap door at the bottom of the chute springs open, sending the trash bags tumbling into a system of pipes below ground. Powerful fans suck the garbage along the pipes at speeds up to 60 miles per hour until it reaches a collection facility no more than 1.2 miles away. The bags plop directly into the waiting bed of a garbage truck, which hauls them off to their final destination.
The truck takes just one trip from the collection point to the dump or recycling facility, instead of making the rounds and stopping at every home and business in the neighborhood. Envac claims this efficiency can curb truck emissions by as much as 90%.
Stockholm has plans to install vacuum waste systems in every new development that includes at least 1,000 homes in a 2 kilometer (1.2 mile) radius. Dahllöf said that density is about the break-even point for a project to make economic sense. The city is mulling over the idea of retrofitting existing neighborhoods with underground pipes, but that’s a much bigger undertaking which would involve tearing up streets and finding land for new collection facilities.
If Stockholm goes that route, the nearby Scandinavian town of Bergen, Norway, offers a vision of its future. No other city has embraced vacuum waste systems more enthusiastically: Authorities are in the middle of installing Envac pipes that will serve every home and business in town, including the medieval city center. The new infrastructure has allowed the city to implement a “pay as you throw” tax scheme, which charges residents based on the amount of waste they generate.
To open the vacuum chutes in Bergen, residents must swipe a key fob registered to their household, which allows local authorities to record data on how much garbage they’re tossing out. Residents can use the recycling and food waste chutes to their hearts’ content—but they can only open the chute for non-recyclables five times a month before an extra tax kicks in. After that, they pay about 85 cents every time they take out the trash.
The nominal fee is meant to nudge residents toward responsible behavior. “When you have to pay as you throw, that of course adds an incentive to sort your waste,” said Kolbjørn Akervold, who heads Bergen’s waste management department. The city also runs a website and app where users can track their own data and see how much money they’re saving by cutting back on waste. “They’re rather simple psychological tricks that we use, but they work,” he said.
In areas where the chutes are installed, Bergen reports that plastic recycling has risen 29% and non-recyclable waste volumes have fallen 8%. Akervold estimates the city is now saving about $2 million per year in garbage pickup costs, and it has seen a drop-off in accidental trash fires, which have long been a menace in older parts of town where wooden buildings are packed close together.
While Bergen’s results are encouraging, it’s unclear how many cities will be able to replicate them. The biggest limitations on vacuum waste systems’ spread are their high upfront costs and the logistical challenges of getting them into the ground. Bergen expects to shell out $140 million by the time the city is done installing pipes in 2023. To minimize disruptions, authorities carefully timed construction to coincide with repairs to other underground infrastructure—but their plans are now delayed because excavations for a new subway line in one part of town have stalled.
Even so, there are some converts. Singapore has mandated that all new developments with at least 500 apartments must install underground waste pipes. China is installing them in planned cities like Xixian, and Envac recently broke ground on a new project in a development on the outskirts of Nairobi.
But Gabriella Carolini, an associate professor of urban planning at MIT, says there’s probably a ceiling on adoption. Cities simply face too many challenges—and too many budget limitations—to realistically expect them to make citywide waste pipes a priority. Where they are installed, she worries they’ll be limited to business districts and new developments, creating a new layer of urban inequality.
“Do I see these systems being installed in wealthy cities seeking to position themselves as technologically advanced to attract more foreign direct investment? Yes—and yay for them,” she said. “But I don’t see this across every city in the world anytime soon.”
Boosters have been heralding the dawn of a new age of pneumatic trash collection for decades. Waste tubes were supposed to sweep across the US starting in 1969, after Disney World debuted the country’s first system. Half a century on, the only adopter has been New York City’s Roosevelt Island, which launched its system in 1975 with the construction of a new utopia-tinged residential development.
While the wave of waste tubes hasn’t materialized, Roosevelt Island’s experience gives us reason to believe that the concept is more than a pipe dream. After 45 years, the island’s waste system is still humming along. It breaks down only occasionally, when residents shove a toaster oven or a Christmas tree or some other oversized piece of trash down one of the cutes, according to chief engineer Al Digregorio. He says workers can usually clear those blockages out in a few hours.
After decades of high-speed trash abrasion, and flooding from Hurricane Sandy in 2012, the pipes are starting to wear out and rot. But every few months, Swedes from Envac fly over to wriggle into the pipes and solder shut any holes they find. Last year, they installed new fans and a modern computer system to control the whole apparatus. “As long as they keep going in and doing repairs, we’ll get another 40 years out of it,” Digregorio said. “I’d say we got more than our money’s worth out of it.”