Water Systems with Jay Abrahams

Jay Abrahams is a microbiologist and permaculture designer who specialises in creating WET water treatment systems for domestic sewage, farming and industry. He coined the term “Treebogs” and gives a talk on designing and building these willow-based composting toilets. Jay is a trustee of the Permaculture Association and runs Biologic Design Ltd. He designed the composting toilets for Crabapple Community.


A Treebog is a composting toilet surrounded by moisture or nutrient-hungry trees like Willow. They use no water, get rid of pathogens and contain the organic waste material. Sweet-smelling herbs such as mint will thrive around a Treebog.

Both faeces and urine are deposited onto the heap inside the bog, with plenty of coveing material like sawdust. The solids compost and the liquids soak through the soil and straw bales to the roots of the Willow. “The associated dense rootzone enables the nitrogen to be rapidly absorbed and metabolised by the mycorhyzal species.” The faeces are contained within the Treebog base, which is well ventilated to allow aerobic decomposition to occur, the composted material feeding the trees around it.

Biologic Design was established in 1993 with the aim of creating integrated, multi-species constructed wetlands for sustainable wastewater purification, biodiversity enhancement and resource production. www.biologicdesign.co.uk