Composting Toilets: Split System vs Self-Contained

Composting toilets fall under two categories: split-system and self-contained.

Split Systems

  • The most extensive type of composting toilet
  • Perfect for large homes, outhouses, parks, and other elevated structures with ample space under the floor

A split-system composting toilet is literally split into two sections: the “pedestal” above the floor and the “tank” under the floor. The pedestal is the toilet seat where you take care of business. The tank is where the solid waste is stored to decompose. A chute separates the pedestal from the compost tank.

Split systems have a larger capacity for solid waste, so they are usually installed in places where multiple people are using the toilet.

A split-system composting toilet is relatively easy to install and set up. However, the composting process can be somewhat technical, requiring a cocktail mix of different elements, organisms, bacteria and fungi to produce humus (compost).

The first chamber is underneath the pedestal component, where the solid waste is collected. A drain extracts the liquid to keep the composting pile at a regulated temperature (moist, not wet). The vent and fan help to evaporate excess liquid. The second chamber is where the end product (compost) is stored.

Self-Contained Systems

  • Smaller capacity compared to split systems
  • Perfect for tiny homes, RVs, boats and other single-level structures that have limited space, or built on a concrete slab, or don’t have a downstairs area for a tank to be installed
  • No plumbing or water connection is required
  • Easy to install / “plug and play”

A self-contained composting toilet is an all-in-one system installed directly in the bathroom. The pedestal and tank are built into a single system, so there is no need for space below the pedestal. This type of toilet closely resembles a standard plumbed-in toilet, so people don’t even realize that it’s a composting toilet until they use it.

A self-contained toilet is nicely compact, with the treatment chamber already inside the toilet pedestal. But because its chambers are smaller, a self-contained toilet has significantly less capacity than that of split systems. A self-contained unit often has extra chambers, so you can swap them out each time you fill up a chamber. You can buy additional chambers if you’re expecting company for an extended period (for example, during holidays).

All self-contained toilets have a bowl liner under the seat, which can be removed for a thorough cleaning.

All composting toilets require composting bulk medium: wood shavings or sawdust, coconut fibre, straw, peat moss, or other organic material.

What to consider before you decide which composting toilet to buy and install:

Still not sure? Get in touch with our team for a free consultation.

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