In the Swedish city of Borås, everyone knows they have to sort their combustibles from their biodegradables or else risk an angry call from Pär Carlsson — who’s part of an army of environmental crusaders working to make this city totally trash-free. Already, less than 4 percent of his town’s garbage is routed to a landfill, and the rest is reused, recycled or morphed into energy to run the local buses and cars. “No waste goes to waste,” says Carlsson, head of strategic development for the zero-waste project at the municipally owned company Borås Energi och Miljö.

Today, Borås is one of the only places in the world that produces almost no waste at all, yet its efforts are part of a broader movement that’s rethinking how to, well, trash our trash. Cities around the world are trying to revolutionize the way garbage gets handled through seemingly sci-fi technology that can convert all manner of household and municipal waste into energy. While some companies like Canada’s Enerkem and Boston’s Ze-gen use gasification techniques, which vaporizes waste into biofuels, others have patented geoplasma technology. The U.K.-based Advanced Plasma Power, for one, uses plasma gasification to turn trash into fuel without producing emissions by using high-voltage electric currents that can heat up to 8,000 degrees, or more, and are almost as hot as lightning.

Borås is so efficient with its waste disposal that it’s even started importing trash from elsewhere in Europe to use in its power plants.

Although the initial investment into these megaplants is huge, the technology can provide a better carbon footprint for a municipality at a lower disposal cost. “We’re more than half the cost of incineration and we can be competitive with landfill [prices],” says Tim Cesarek, senior vice president of Enerkem in Canada. The sales pitch has worked for Enerkem, which is ramping up production at its facility in Edmonton and has signed two deals for plants in China.

As cities get squeezed for space for landfills, more are rethinking their garbage disposal strategies. In Manhattan, another Swedish company called Envac is testing its special vacuum waste collection systems — effectively a subway for garbage that will make trash disappear like magic into pneumatic tubes. Last year, Envac signed a deal with Hudson Yards, a $20 billion megaproject, to provide the system for the development, and the company already has its equipment on Roosevelt Island, the thin strip of land near Manhattan. The project “will create ripples not just in North America, but all over the world,” Christer Öjdemark, Envac’s chief executive, said at the time.

Meanwhile, in Sweden, Borås Energi och Miljö turns everything from plastic bottles and leftover dinner to batteries and paint into energy for heating and cooling, including 3 million cubic meters of biogas — enough to run 50 local buses and 250 cars. Tap water gets recycled, hotels send garbage to state-of-the-art recycling centers, and a power plant and hydro stations power the town’s eco electricity. Signs around town also tell visitors to discard their rubbish into the right black and white optic bags.

Others have been inspired to take action. Recology, a private waste-management company that handles San Francisco’s garbage, is helping it become the country’s first zero-waste city in a mere seven years. The city has relied on local ordinances and regulations that require every resident to recycle and compost to divert 80 percent of its waste away from landfills — the highest rate in the country.

Yet skeptics say that zero-waste in one city won’t mean zero-waste in another. Robin Nagle, for one, isn’t convinced. The New York University anthropology prof studies garbage for a living and is the “anthropologist-in-residence” for the NYC Department of Sanitation, where she worked as a uniformed sanitation worker. “If we did achieve zero-waste,” she says, “it would sound good and it would have lots of good spin, but it wouldn’t actually make the planet a better place.”

That’s because household waste accounts for less than 3 percent of total waste, she notes, leaving thousands of tons more trash to decompose on a landfill site. And with the U.S. making about 250 million tons of trash a year, it would take much bigger and many more plants to handle the nation’s municipal trash output, even with recycling and composting facilities like the ones in San Francisco that tackle an estimated 85 millions tons of refuse per year.

Borås, however, sometimes called the “North of Venice” for the river that runs through it, is so efficient with its waste disposal that it’s even started importing trash from elsewhere in Europe. The city uses the garbage in its power plants because it needs more energy to convert, and it has struck agreements to launch plants in all corners of the world, including Savannah, Georgia, Vietnam and Ghana. It even managed to persuade the United Arab Emirates, which has one of the biggest carbon footprints in the world, to join a global clean energy network. “We are on the international map now,” says Carlsson.

