as an effective child-proof barrier and allows air to circulate through the compost heap. Plastic mesh or chicken wire coated in plastic would prevent problems with rusting. Sawdust, straw, woodchip, ash or other high-carbon matter is used to cover the excrement and balance the high nitrogen content of the urine. One design uses bran to help mitigate the odours. The space between the two layers of mesh is stuffed with straw, which acts as a wick to help sop up excess urine, preventing the likelihood of odour problems due to incomplete biological absorption of the nitrogen from the urine. The straw-filled wire also enables the pile to be well-aerated whilst acting as a visual screen for the first year’s use. The structure is surrounded by two closely planted rows of Salix viminalis or other willow cuttings; this living wall of willow can then be woven into a hurdle-like structure and its annual growth can be harvested. See also Arborloo , a similar concept, in which excrement goes into a hole in the ground and, when the hole starts to fill, the outhouse is moved to another hole, and a tree is planted in the old hole. Ecological sanitation Reuse of excreta Urine-diverting Dry Toilet References External links Build your own Treebog Toilets Toilet types Phytoremediation plants Home composting Permaculture Sustainable building Sustainable technologies Bioremediation