A new source of fuel in Japan
As use of adult diapers grows, one town’s recycling efforts don’t let waste go to waste
HOUKI, Japan — The restorative waters that flow into the public baths in this town near the coast of western Japan originate from hot springs more than two-thirds of a mile below ground. At the surface, before the water bubbles out of the spouts, it is further heated to 107 degrees — an ideal temperature for cleansing and soaking weary muscles.
But unbeknown to most bathers, the boiler heating the water runs on a fuel with the uncleanliest of origins: pellets recycled from soiled adult diapers.
In rapidly aging Japan, more diapers are used by older, incontinent people than by babies. As the country groans under the weight of ever-rising mountains of this waste, the town of Houki has become a pioneer in trying to reduce it. By recycling the diapers, which represent about one-tenth of the town’s trash, it has diverted garbage that would otherwise be dumped in incinerators and add emissions to the atmosphere.
With many other nations facing a similar demographic implosion, adult diaper waste is a stealthy challenge that looms alongside labor shortages in nursing homes and insufficiently funded pension systems.
“It is a difficult and big problem,” said Kosuke Kawai, a senior researcher at the National Institute for Environmental Studies. “Japan and other developed countries will face similar problems in the future.”
In Houki, a town of just over 10,500 people, officials were worried about the fast-growing diaper waste and looking at the costs to upgrade an outdated incinerator. They decided to convert one of the town’s two incinerators into the diaper recycling plant and produce fuel that would help reduce natural gas heating costs at the public bathhouse as well.
At the baths, there is nothing advertising the provenance of the boiler fuel. Satomi Shirahase, 45, who was visiting with her husband from Kyoto, was unperturbed when she learned of the source of the heat.
“I am not creeped out. It was good water,” she said in the dressing room after hiking on nearby Mount Daisen
The diaper challenge is especially great in Japan, where more than 80% of the country’s waste goes to incinerators — higher than in any other wealthy nation — despite a near obsession with sorting trash.
The amount of adult diapers entering the waste stream in Japan has increased by nearly 13%, to almost 1.5 million tons annually, in the past five years, according to data from the environment ministry. It is projected to grow a further 23% by 2030, when those 65 and older will represent close to one-third of the population.
Because diapers contain so much cotton pulp and plastic, and swell to four times their original weight after soiling, they require much more fuel to burn than other sources of waste. That leads to costly waste management bills for local municipalities and high volumes of damaging carbon emissions.
Acknowledging the growing problem, Japan’s Environment Ministry convened a working group last year to discuss alternatives to incineration for diapers. A handful of other municipalities are following Houki and turning the diapers into fuel pellets, while some are experimenting with converting them into material that can be mixed with cement for construction or road paving.