Treebog

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A treebog is a simple, water-free compost toilet built on a raised platform above a compost pile and surrounded by a living wall of nutrient-hungry trees such as willows. It turns urine and faeces into biomass without handling waste and is a small example of permaculture design.

Waste goes into the pile, where solids decompose in air and liquids soak into the soil. The system is ventilated to limit odour. Carbon-rich materials like sawdust or straw cover the waste to balance nitrogen. A seat sits at least a metre high, and the space below is enclosed with two layers of mesh to keep children safe and allow air to move. Straw between the mesh acts as a wick to soak up urine and reduce smells. The surrounding willow rows form a harvestable living wall around the structure.

The term “treebog” was coined by Jay Abrahams. About 1,500 were built in Britain between 1995 and 2011. NGOs have shown interest in using treebogs for places with little water, such as shanty towns or refugee camps. In the UK, such systems may be legal if they are not in public places.