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 Fahrenheit — 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.