Il ne s'agit pas de toilettes sèches (composting toilets), mais de toilettes sans chasse d'eau, installées sur fosse en béton le plus souvent, non septiques, non chimiques. La fosse est un simple réservoir qui doit être vidé périodiquement.


" Vault Toilets

The common solution for sites without running water or access to a sewer system is what is called a "vault toilet." Waste is held in an underground vault or tank, usually between 750 and 1000 gallons in size, which is pumped out periodically. Vaults are made of concrete or plastic material. The most popular type of vault is made of reinforced cross-linked polyethylene. This material will not crack or leak, so it meets all environmental standards.

A typical vault toilet installation has the vault buried in the ground with a concrete slab poured in place directly over it. The building is installed on the slab with connections to the vault for the toilet and vent pipe. This type of system provides a permanent, odor-free and accessible toilet at a fraction of the cost of site-built structures.

"Odor free?" Yes, they've even figured out to keep vault toilet buildings from smelling so bad. Thanks to research by the U.S. Forest Service, stinky privies are now a thing of the past. The trick is to design the building and vent system so fresh air naturally flows through the building and out of the vault and vent pipe. The Forest Service calls this design the "sweet smelling toilet," and it really works.

Pre-fabricated vault toilet choices range from buildings made of cross linked polyethylene (same material as the vault), to wood frame construction, to reinforced concrete structures. Both single, "unisex," and double vault toilet systems are available. The concrete designs are often chosen for their superior durability in vandal-prone areas."
http://findarticles.com/p/articles/mi_m1145/is_n7_v32/ai_196...

"celles de la toilette se déversent dans la fosse septique et elles s'évacuent ... L'installation d'une fosse de rétention</B> (vidange périodique ou totale) n'est autorisée que pour les camps de pêche et de chasse et les résidences existantes où les .... sans phosphate. Le phosphore ne se décompose pas et favorise la ..."
http://www.lacdelest.org/.../Guide de gestion des installati...