Unicharm to develop water-saving ‘dry washing’ technology for nappy recycling in Kagawa

Unicharm Corporation has announced a new partnership with Fuji Clean Co., Ltd. to develop a “Dry Washing Method” for recycling used disposable nappies (diapers). Their goal is to reduce water consumption in the recycling process to approximately one-fiftieth of conventional methods. The companies has established this technology in Kagawa Prefecture, and intend to create a circular model that can be deployed in water-scarce regions and overseas markets where infrastructure may be limited.

Since 2010, Unicharm has actively pursued the recycling of disposable nappies, previously achieved a world-first in 2019 by generating recycled pulp of equivalent quality to virgin materials using an ozone treatment technology in Shibushi City, Kagoshima Prefecture. This allowed for horizontal recycling, where used nappies are processed back into new nappies.

However, a persistent challenge remained regarding the scalability of this system. The conventional cleaning process requires substantial amounts of water to ensure the sanitary breakdown of waste. This reliance on water resources and extensive wastewater treatment facilities meant that the system was difficult to implement in regions lacking abundant water or robust infrastructure. Unicharm recognised the need for a more efficient, resource-light technology.

The new “Dry Washing Method” addresses this limitation by applying principles similar to commercial dry cleaning. Instead of water, the process utilises a reusable solvent combined with proprietary sterilisation and bleaching technologies. This approach allows for the hygienic cleaning of used nappies while suppressing water usage to a fraction of what was previously required.

By drastically lowering the water footprint, nappy recycling becomes viable in a wider range of environments. This development marks Unicharm’s first recycling initiative in Kagawa Prefecture, while Fuji Clean will manage the collection of used nappies within the region.

The companies plan to commence technical development at a testing facility within Fuji Clean’s premises in 2026. Following this research phase, they intend to construct a full-scale resource recovery plant in 2028. Full operations, including the formal collection of used nappies in collaboration with neighbouring municipalities, are scheduled to begin in 2029.