Vacuum waste: A tech whose time has finally come
Underground trash systems can eliminate curbside bins and improve recycling rates. Cities are catching on.
By Philip Preville
Wembley Stadium has hosted a long list of memorable cultural and sporting events throughout its history. Until recently, however, the grounds that surrounded the stadium have been distinctly unmemorable. “What we had, in the area surrounding Wembley, was an old area of industrial units and parking lots in desperate need of regeneration,” says Chris Whyte, the director of environment services for the London borough of Brent, which Wembley calls home.
Over the last 12 years, Whyte has helped Brent lead the transformation of the 85-acre site into a vibrant neighborhood of mid-rise residential and commercial buildings. Now known as Wembley Park, the area has become memorable in a new way, for something it lacks: there is no curbside waste pickup in the development. Instead, all the waste in Wembley Park travels via an underground vacuum collection system.
Whyte recalls that the developer of Wembley Park—the London-based company Quintain—came to Brent with the “unusual proposal” for what’s essentially a sewer system for garbage, powered by pressurized air instead of flowing water. The borough was intrigued by the idea of creating a neighborhood free of London’s ubiquitous “wheelie bins,” but it was also wary. Vacuum waste collection was well-established elsewhere, used in hundreds of developments in more than 30 countries. But in the U.K., as in most of the world’s 195 countries, it was virtually unknown.
“No development in the U.K. had ever installed this kind of system,” says Whyte.
That’s why, back in 2008, Whyte ended up as part of a Brent borough delegation to Stockholm to see the proposed system in action. Two key findings convinced them to approve it for Wembley. One, the system improved the overall appeal of the neighborhoods where it operated: cleaner streets, fewer odors, and no curbside collection bins or trucks. Two, it made a pronounced impact upon recycling rates, particularly in mid-rise and high-rise residential buildings. Indeed, Sweden’s wider adoption of vacuum waste is one reason why the country sends only 1 percent of its household waste to landfill.
Twelve years on, Wembley Park’s automated waste collection system serves a mixture of residential, retail, and hotel properties with more than two and a half miles of underground tubes. It has the capacity to handle nearly 6,000 metric tons of waste and recycling per year — and its recycling rate is double the U.K. average. This is no small contribution to the fight against climate change, since plastic production accounts for some 3.8 percent of global carbon emissions, and recycling is the best way to curb them. And recycling is just one of vacuum collection’s sustainability benefits: it also reduces the substantial methane gases generated from landfill, as well as the carbon emissions from garbage trucks, the worst climate offenders in any municipal fleet.
But beyond Wembley, vacuum waste “hasn’t really taken off here in the U.K.,” says Whyte. “It’s unfortunate, because it has worked really well here.” The U.K. is not alone in this regard; North America has also been averse to pneumatic waste collection. But as its advantages in sustainability and urban design have become clearer, vacuum waste seems to be a technology whose time may finally have come.
From trash cans to vacuum tubes
Throughout urban history, the main issue with waste has been how best to get rid of it. Cities of centuries past tried every scheme they could imagine: burying it, burning it, dumping it into waterways, piling it up outside city gates, feeding it to swine, the works. Nothing stuck until 1875, when the British Public Health Act mandated that every home had to put its waste into a “movable receptacle“ for civic authorities to collect — the invention of what Britons call the dust bin, and others the garbage can.
Nearly 150 years later, the basics of the collection system remain unchanged, save for the fact that waste collectors now drive heavy-duty trucks instead of horse-drawn carts. And as cities have densified, so has the trash. High-rises require ever-larger dumpster bins and collection areas. Recyclables and compostables are difficult to separate in high-rises as tenants often dump all their trash into a single chute, leading to cross-contamination of waste streams. Recycling rates in tall buildings are generally much lower than in single-family homes (one recent U.K. study found them to be 50 percent lower).
As a result of this overflow, sidewalks that could accommodate benches, patios, trees, and street life must instead make room for the endless flow of trash. “Rising densities mean more trash getting piled up on the same amount of curb space,” says Juliette Spertus, a New York City architect and researcher. “As a result, we have to prioritize waste on the curb, especially food waste, because restaurants have collection all the time.”
Spertus — who curated the 2010 exhibit Fast Trash about New York’s lone vacuum-waste system on Roosevelt Island, which was installed in the 1975 and is still in operation — says it’s not just the sidewalks that suffer. “Buildings in New York City, their staff and residents, spend outrageous amounts of time handling waste,” she says. “They are always sorting trash, managing compactors, and shuttling bags and bins. On Roosevelt Island, building supers spend no time on this stuff. It’s just not an issue.”
Both the Roosevelt Island and Wembley Park systems were built by the Swedish firm Envac, whose founder, Olof Hallström, is credited as the inventor of pneumatic waste collection. His firm was initially in the business of installing central dust vacuum systems. In the late 1950s, Sweden’s Solleftea hospital asked Hallström if it was possible to vacuum up all the trash as well as the dust. The idea wasn’t that far-fetched. Beginning in the 1850s, the major cities of Europe all installed networks of pneumatic tubes to shuttle mail and other messages between downtown buildings and offices. Berlin’s Rohrpost network featured nearly 250 miles of tubing at its peak; Paris’ poste pneumatique, the world’s most extensive, had over 290 miles.
By the 1950s, pneumatic post had been displaced by telephones and mail trucks. But Hallström believed the technology could still have a future in trash. He designed the system himself, and it was installed at Solleftea hospital in 1961. Four years later, the Stockholm-area municipality of Sundyberg installed Hallström’s system in a municipal housing development — its first use in a residential setting.
How it works
A typical vacuum waste network starts in the garbage-chute room of a residential high-rise. Typically, that chute leads to a dumpster bin in the building’s bowels. In pneumatic systems, the chute connects to an underground pipe that leads directly to a neighborhood waste collection center.
Early pneumatic systems featured a single chute. Today there are multiple inlets, one for each waste stream. Wembley Park’s pneumatic collection has separate inlets for three waste streams: non-recyclable waste, dry mixed recyclables, and organics. The ease of this system has doubled recycling rates and collected five times more organic material, compared to U.K. national averages.
As residents deposit waste down their respective chutes, it comes to rest atop a valve that opens into the main underground pipe, called the trunk line. The valves are opened one at a time, allowing each stream to flow separately through the trunk line to the collection center. Each stream’s valve is opened on a regular basis, whether daily or bi-weekly. In other words, vacuum waste systems still operate on a collection schedule, but residents never need to worry about missing the truck.
The system’s pneumatic tubes are powered by large vacuum pumps located in the collection center. The pumps are powerful enough to transport waste at speeds of up to 40 miles per hour. That requires a lot of electricity, but the pumps don’t operate continuously; rather, they run only as the system’s valves are opened. Wembley Park’s vacuum waste system consumes 300 kilowatt hours of electricity daily. That’s about one-tenth of a kilowatt-hour per day for each residence served by the system, roughly equivalent to the consumption of a 100-watt incandescent lightbulb for 70 minutes.
Once the waste arrives at the collection center, a final set of valves directs each waste stream into separate containers. Once full, they’re transported by trucks for final disposal. In Wembley Park’s case, recyclables go to a materials recovery facility, non-recyclables to a waste-to-energy plant, and organics to a digester. Nothing goes to a landfill.
As a final benefit, the system dramatically reduces truck traffic (and related diesel emissions), because trucks now pick up waste from the collection center instead of combing the entire neighborhood. In Wembley Park, truck movements for waste collection have been reduced by 90 percent, saving more than 400 tons per year in carbon dioxide emissions. That figure is expected to rise to nearly 700 tons per year once the redevelopment is complete.
Higher upfront costs, but many benefits
Given their advantages in both curbside cleanliness and sustainability, vacuum waste systems have been surprisingly slow to catch on. Pneumatic collection runs counter to the age-old norms of curbside collection in more ways than one, and old habits are hard to break.
One of the most common criticisms of vacuum collection has always been that, as fixed infrastructure, pneumatic collection is inflexible to changing waste management needs, such as the adoption of recycling programs. But the higher recycling rates in Wembley Park (and in Sweden) suggest that pneumatic collection has adapted better to recycling than traditional collection and its proliferation of color-coded bins.
In addition to vacuum waste’s undeserved reputation for inflexibility, it is also frequently criticized for being expensive. According to Benjamin Miller, New York City’s former director of policy planning for waste management, this is partially true. “Vacuum waste systems require an extra layer of planning, and they require significant upfront capital investment,” he explains. The infrastructure typically needs to be installed, and the collection center built, before a single resident moves in. “That raises new questions about who pays for what.”
In Wembley Park, the numbers crunched favorably for everyone. According to a 2011 report prepared by Brent Council, the up-front capital costs for the Envac system amounted to more than $16 million. Once built, however, its operation has come at substantial savings: that same Brent Council study pegged the operational cost of the Envac system at under $275,000 per year, compared to the nearly $900,000 annual cost of curbside collection. To make the finances work, the borough and the developer arrived at a unique arrangement: the developer would pay for the system’s construction and operation, while the borough would pay for part of the collection service.
“The borough is responsible for residential waste, but businesses arrange their own disposal at their own cost,” explains Whyte. “The challenge of the vacuum system is that it collects waste from residents, hotels, restaurants, and other businesses all at once. We had to agree on a formula for determining what fraction of waste was residential.”
The borough reaps some savings from the system’s higher recycling rates. “For Brent, there are financial and sustainability benefits to the arrangement,” says Whyte. The developer, meanwhile, reaps substantial economies of space from the system, because it eliminates the need for bins, dumpsters, and sorting and storage areas in the bowels of Wembley Park’s buildings. At one site, the 295-unit Landsby development, the vacuum collection system resulted in an additional 2,000 square feet of retail space.
Estimates suggest that, once Wembley Park is complete, the pneumatic waste system will have saved a total of approximately 30,000 square feet — areas that can instead be repurposed as retail, office, residential, or common space.
The world’s waste awaits
While vacuum waste collection is still rare compared to curbside pickup, its adoption may be on the rise. Norway’s second-largest city, Bergen, is installing one of the world’s largest vacuum waste systems, with nearly 5 miles of underground pipe. In 2018, Singapore changed its development requirements so any project of 500 apartments or more must collect waste and recycling via vacuum tubes, and gave itself the authority to designate whole districts as pneumatic waste collection zones.
North America remains a laggard, but some promising projects are underway. In New York, Benjamin Miller and Juliette Spertus have teamed up to create Closed Loops, an organization whose objective is to bring pneumatic waste collection to the city. The two met while working together on a pneumatic waste collection research project at the City University of New York. “We’ve been working together ever since, trying to catalyze these kinds of projects,” says Spertus.
Their first target is not a large-scale redevelopment but the city’s famed High Line Park and its adjacent buildings. Their proposal for the High Line district involves a clever maneuver: suspending the pneumatic trunk line above ground, in the rafters beneath the High Line’s raised platform.
Typically, installing pneumatic systems in older urban districts can be a more expensive proposition than a new, large-scale redevelopment, since it requires retrofitting existing underground infrastructure to accommodate the vacuum tubes — a challenge that the Closed Loops proposal elegantly skirts. Their proposed High Line system would also include a separate stream composed exclusively of organic kitchen waste from nearby restaurants, which would be transported to a nearby anaerobic digester, where it would be turned into biogas and fertilizer.
The proposal has widespread support from all levels of government, as well as building owners and major corporations along the High Line corridor. “It’s not shovel ready, but it’s close,” says Miller. If all goes well, the project could get the green light in 2021 — potentially paving the way for other pneumatic projects to follow, in New York and beyond. Pneumatic trunk lines could run beneath any city’s elevated expressways or rail corridors, or even in its subway tunnels, not to mention any neighborhood-scale developments.
“The High Line is a very visible and well-known location that would make a great pilot,” says Miller, “but there’s lots more low-hanging fruit we could pick.”
Philip Preville is a writer based in the Toronto area.
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