Japanese architectural studio Tono Mirai Architects designed a structure made of rammed earth and wood that encloses public toilets in a park in Miyoshi, Japan.

Called Toiletowa, the structure has a rammed earth wall made of recycled soil. Called NS-10, the material consists of soil from demolition sites, mixed with pulverised gypsum board. Until now, the material had only been used as roadbed material for pavement.

The rammed earth does, however, lack compressive strength. Therefore, it was applied to a wooden structure. The same material mixed with lime was used for partitions and the hard-packed earthen floors.

The foundation is made of crushed stone instead of concrete, to reduce environmental impact. Inside, the wash basins and toilet bowls are made of recycled wood chips.

In addition to the toilet building, there is also a semi-circular tank building located at the site. This building is made from cedar boards of different widths. The toilet uses a biotechnology called combined fermentation (EMBC) to treat the wastewater, which is used in a closed-loop system.

Photos: Takeshi Noguchi