Looking For a Simple Sanitation Solution that will W.A.S.H.

Updated: Jul 6

Could Assisted Self-build Latrines, such as The Treebog, improve toilet provision in Refugee and IDP camps?


Image: A Treebog is Self-Built in Senegal by the Jiwnit Community


An interesting exchange arose between Re-Alliance members Jay Abrahams, microbiologist and founder of Biologic Design Ltd, a UK permaculture design consultancy which creates regenerative, natural wastewater and water systems, and Richard Luff, an experienced WASH engineer who has worked in refugee camps.


When Jay wanted to introduce the Treebog into the humanitarian sector, both he and Richard discovered they had ideas for improving toilets for refugee and IDP camps.


Here we use extracts from their exchanges to look at their practice and ideas in more detail.



The Problem with the Status Quo


Ask anyone with an interest in toilet provision in emergency situations and almost all will agree that the current norm of communal latrines, emptying into underground concrete-lined pits, is problematic. Environmentally, the latrines require large inputs of financial and material resources, as well as labour and energy, to install and maintain. They require ongoing regular pumping with suction tankers, and the removal of ‘wastes’ before eventual treatment and disposal.


Although rapid provision of toilets is needed to meet basic human needs and prevent the spread of diseases, the legacy of rapidly installed latrines can create harm for both people and planet for many years. In situations where resources are often scarce, conventional latrines are also extremely wasteful.


From a humanitarian perspective, community latrines which are installed without the participation of those using them can create an environment where the abuse of vulnerable groups, including women and girls, is exacerbated.


As Richard Luff puts it:


“Despite increasing attempts to provide latrines in acute emergencies that meet most girls’, women’s and other vulnerable groups’ needs, the WASH sector modality of building communal latrines consistently fails to do this.” because they cant be built fast enough in the early stages of a rapid onset refugee/IDP crisis“

A Self-Build Solution


Both Richard and Jay have innovative ideas to address the problem of communal latrines, through the rapid building of latrines for each household or family group. Richard proposes that humanitarian agencies:

“Develop Assisted Self-build Latrine approaches for all emergency response situations in order to phase out communal latrine building and instead focus on latrines for family use”

Here the structures would be built primarily by users rather than agencies which could provide more dignity and safety earlier on. Moving to a notion of self-building shelter/housing is becoming more established in disaster response situations:

“The shelter sector has for the past few years been focussing on supporting self-recovery, with the aim of enabling households after disaster and refugees to build their own shelter and homes.”

Although the benefits of self-building are acknowledged, enabling households in both disaster and refugee situations to be active participants in building back better and safer, not much, if anything, has been done on agency assisted latrine self-build in refugee camps. Richard suggests this is because:


“There is one major difference between a shelter and a latrine; an unsafe shelter may harm the family using it, but an unsafe latrine that leaks faecal matter into the environment could contaminate and harm many others.”

However, this potential harm should be weighed against the actual danger posed daily to women and girls using communal latrines, and mitigated against through agency supported safe and durable design and implementation. Wider ecological impacts should also be taken into consideration.


Treebogs - A regenerative design


Treebog at Jiwnit Community Senegal over time

Trees planted Oct 2019 May 2020 - rapid growth April 2021 the Papaya is fruiting



One such design could be the Treebog. Jay Abrahams developed Treebogs for his own off-grid living situation in the UK over 30 years ago. Today hundreds of Treebogs have been built and function well in the varied climates of Portugal, Greece, Spain, Nepal, Israel, Palestine and Senegal. The Treebog has become a successful ‘technology’ in both rural and peri-urban settings within Europe, often self-built using hand tools, local natural materials and planted with indigenous tree species.


Treebogs are a compost toilet with a platform mounted toilet seat or squat, in a cubicle, surrounded by closely planted, economically valuable and useful, trees and shrubs. This arrangement enables the faeces and urine to be deposited on the soil surface, underneath the platform, where the solids are composted into soil, while the liquid soaks into the earth below, feeding the root zone of the planted species surrounding the Treebog.


Jay suggests that with self-built Treebogs the maintenance of the structures and their management is the responsibility of the family using the latrines, and so they are more likely to look after the latrine and keep it clean and functional - as well as harvest the yield from the trees. Treebogs are comparable to standard compost toilets in that they compost waste and do not use water for flushing, but are unique in design. They hold wastes on the soil surface (above-ground), within an aerobic chamber beneath the seating/squatting platform, this enables rapid aerobic decomposition so the wastes are composted in-situ and no secondary handling is needed. Fast-growing, useful and economically valuable trees are planted around the structure to enhance liquid take-up and composting of the solids. The plant nutrients within so-called ‘waste materials’ are broken down by soil microbiota (bacteria, archaea, fungi, protists, beetles and earthworms) and then absorbed through the roots into the growing biomass of the trees.


When full, Treebogs are closed and the contents are left to compost or rot, if required they can be safely emptied by hand after about a year to 18 months, once the wastes have been fully composted to soil.


Richard suggests the use of a twin Treebog system in refugee camps where loading rates i.e. number of users, are typically much higher, would help where there are space constraints.


Jay explains:

“A Treebog empowers local people to take control of their own ‘wastes’. It gives them the ability to create soil, begin a home garden, and create resources locally, with very little input from outside actors. Once a Treebog is established and planted with trees which can be coppiced for polewood, it is possible to literally ‘grow' the materials to construct more Treebogs!
A Treebog is a tree-growing, soil-creating mechanism and the soil life which inhabits the compost pile - the earthworms and dung beetles in temperate regions and the termites and ants in the tropics - all benefit the web of life that the Treebog creates, so local biodiversity is enhanced.”

The Treebog design is simple to implement and has benefits beyond toilet provision:


“There is no need to dig deep pits, which actually bring the septic wastes into closer proximity to the groundwater and so can increase the possibility of pollution of this resource. Dozens of trees are grown around the structure when the Treebog is created. Trees provide us with many of the ‘ecosystem services’ we need for life and not to include trees in the overall design of refugee camps – indeed settlements in general – is to miss a trick.”
“In places where resources are scarce, a low-tech solution may be more appropriate than high-tech or energy intensive solutions. As a biologist practicing permaculture design, I am able to ‘trust the biology’ to do the job. Because the Treebog concept is so simple it has not yet found support amongst the NGOs responsible for operating these camps who may well be more comfortable providing engineered solutions”.



An metal frame Treebog in Senegal - showing the adaptability of design


Aid agencies and NGOs may feel that research and development is needed to prove the safety, durability and scalability of Treebogs. If so, Jay hopes to hear from any agency willing to explore the potential for creating and planting Treebogs using local resources, with a view to building a protocol that NGOs can work with, flexible enough to adapt to local situations. Richard suggests the use of an adapted twin pit Treebog system in refugee camps where loading rates i.e. number of users, are typically much higher, would help where there are space constraints and pit closures are often not possible.



From Waste to Resource


The principle behind the Treebog is a paradigm shift: from seeing human ‘waste’ as a problem to seeing it as a resource.


Jay describes:


“A Treebog is a biologist’s approach to toilet design, viewing the organic matter and nutrients as a potential resource, because within the cycle of life there is no such thing as a waste. Conventional development systems/solutions use a Newtonian world view, a ‘world as machine’ approach, which views the waste only as a problem to be got rid of rather than as a resource for growing plants and trees.”

However, for wastes to become a resource, the risks related to contamination and health need to be acknowledged and any potential harm prevented. Identifying possible limitations of the Treebog design could be key to its successful adaptation to disaster situations. For example, its unique design using above-ground aerobic digestion could make Treebogs vulnerable to landslides or flooding - but current practice is susceptible to these same risks, and have on many occasions failed the populations they are serving. With an initial investment to trial Treebogs in Refugee or IDP camp situations, the design could be modified to adapt to adverse conditions.


While Treebogs may not be suited to all conditions, clearly defining and understanding the Treebog’s benefits and limitations mean they could be used as part of a mix of appropriate solutions. The simplicity of the Treebog concept means it could be adapted in partnership with the residents of camps to suit varying cultural and environmental conditions, and also makes it ideally suited to self-build.


Jay believes that self-built Treebogs could provide many ‘ecosystem services’ which can benefit the health of the communities living in the camps, as well as surrounding biodiversity and ecological health. This is an approach that Richard believes could support other work he is undertaking to promote biodiversity net gain for healthy settlements, whereby trees, shrubs and other plants can play a significant role to improve residents health in a number of ways, alongside other co-benefits.


A regenerative solution is diverse and responsive


Interesting sustainable designs are being invested in, for use in camp situations, such Oxfam's Urine Diversion Dry Toilets and Tiger Worm Toilets, but as yet they are all ‘top down’ modifications to agency-installed communal latrines. Until the users of latrines are involved in elements of the design, implementation and maintenance of their latrines, novel solutions can’t be truly considered Regenerative. There are some cultures that maintain deep reservations about handling human “waste”, so bringing them to an understanding and acceptance of the resource aspect is also a prerequisite. To move forward in a regenerative way, a diversity of solutions is needed to adapt to communities’ varying needs and environmental requirements. Assisted Self-Built Latrines and Treebogs could be part of this solution.


Re-Alliance calls to Aid Agencies, Humanitarian organisations, and funders to partner with us and our members to trial these innovative solutions.


Further reading:

R. Luff note on Assisted Self-build Latrines


Case study https://www.re-alliance.org/post/integrating-compost-toilets-tree-planting soil-building-in-rural-senegal


R. Luff note on Biodiversity net gain for healthy settlements https://www.sustainability-centre.org/tree-bog.html