The Composting System for Black Water At Desert Rain

As an intensely sustainable custom home, Desert Rain is making waves again with it’s newly installed composter/evaporator. With a gray water system already in place, the black water treatment is an important piece of the work required to earn the Living Building Challenge Water Petal. The Water petal requires that all of the water on the Desert Rain property is collected as well as treated for use again and again.

The Phoenix Composting Toilet

The newly installed composter – a Phoenix – will treat all of the black water, making it safe to reuse for landscape irrigation.


How does the Composter work?

At first, the composting chamber is “charged” with wood shavings, peat moss, and water to provide an environment that will be conducive to biological decomposition. Waste, brought from the residences toilets to the composter via a vacuum system, will gradually build up in the tank and decomposes through the action of aerobic bacteria. The Desert Rain system will also include worms (the same worm used in backyard composters) to aid the process. Within in the composting unit, there is shaft with tines that is rotated to mix the decomposing waste and ensuring adequate oxygenation. An electric fan and vent pipe are located at the top of the tank to pull fresh air into the tank through specially designed air baffles in the sides and to remove gases and odors.

The Phoenix Composter