top of page

Integrating Compost Toilets, Tree Planting & Soil Building in Rural Senegal

In 2019 in rural Kamyaak, Senegal, residents with local organisation Jiwnit invited Jay Abrahams of Biologic Design (a UK regenerative water systems practitioner) to work together to build two double Treebogs, a simple and effective compost toilet, and a non-infiltration swale fed by rainwater from a shed roof. Planted around the Treebogs and along the swale edges 100 carefully selected trees were planted. The Treebogs give toilet facilities to the local community and the trees are fed by the nutrients in the faeces and urine and watered by the washing water. The Treebogs create fertile soil and productive trees, for food, fuelwood and polewood for construction.  A pre-existing orchard and vegetable area are watered by the 100 metre rainwater harvesting swale ditch. Local involvement and learning was built by sharing and talking with the community and

a slideshow by Jay to build awareness of how all water passing through a site can be used. Local carpenters guided by Jay learnt about Treebogs as they constructed them and swale digging and tree planting was done by the community.


In Kamyaak, residents rely on growing their own food and on livestock for their livelihoods, in a challenging region where drought has led to desertification and land degradation. The Rainy Season is providing less rain, often for shorter periods and the six metre deep groundwater wells of the local villages are now giving saline water. Residents are working to regenerate the village with local organisation Jiwnit, their aim is to build soil and use harvested rainwater systematically to grow vegetables, fruits, herbs and trees.

This project brought together the skills of local carpenters with the regenerative  design skills of Jay Abrahams. If you would like to build Treebogs in Senegal or design and implement integrated water-retention systems, you can contact Jay and Jiwnit by following the details at the bottom of this page.

Above: Led by local carpenter Aziz, villagers build the Treebog.


How can integrated water retention landscapes with densely planted Treebogs and rainwater harvesting swales  help communities battling desertification  ? 


  • Soil is created and enriched below and around the Treebogs, and when planted with trees, helps combat desertification.

  • Swales and Treebogs are passive systems that do not require energy from non-renewable sources to operate. This is in contrast to pit latrines or flushing toilets which fill underground tanks or pits, which need to be pumped out and the contents tankered away and can negatively effect groundwater.

  • Treebogs use 'wastes' as a resource and feed the plant nutrients directly to productive trees and shrubs.

  • Rainwater is harvested and retained by swales rather than it running off the land, which can cause erosion.

  • With the extra water and nutrients trees grow more quickly and are bigger and healthier, increasing the local biological resource base and enhancing biodiversity.

  • Trees and plants thrive absorbing carbon dioxide, shading the ground from scorching in the sun and creating habitats for other plants and wildlife, while their roots hold water within the landscape.


  • Low cost, clean, safe toilets built by the community, for the community. In an area where there are some flush toilets but the main option is open defecation the privacy and safe space provided by the Treebogs is especially valued by women.

  • Treebogs are welcomed by villagers because there is no need to dig out or otherwise handle or move waste.  It is composted in place and absorbed by trees planted densely around the Treebog.

  • Increased resources are created from the nutrients and water in harvested rainwater, washing water and toilet wastes. 

  • Trees provide food, coppice materials, shade, traditional medicine ingredients, wood for crafting and building and animal fodder.   

  • Fertile soil is created which can grow food for household use.

  • Livelihoods are promoted by hiring local craftspeople for building and increasing the skills and capacity of everyone involved through knowledge sharing.

  • Capacity building for around 200 people who took part in a 10-day workshop, increasing awareness of rainwater harvesting for resource production, along with environmental protection and enhancement. 

  • Increased sense of self-action and self-improvement; ideas spread by example throughout the locality.


The creation of tree planted swales and Treebogs regenerates the land and enhances lives. Using low-cost or freely available local inputs, Treebog toilets enable trees to thrive and soil is created. There are multiple long-term benefits to people and place with little or no environmental cost.

Above: a team from Kamyaak Village  dig swales using handtools.


How can this and other similar projects develop in the future?


Experience from the UK and around Europe shows the potential for large numbers of Treebogs which can be adapted to varied local conditions.  ​​ The toilet wastes within a Treebog are composted in-situ, reducing costs and logistical management. Cutting out the disposal, handling and transportation of waste by instead using it for soil production and ecosystem restoration. Treebogs are widely used in Europe where they are helping to create tree based, productive landscapes and home gardens.

Water retentive swales are used by Jay extensively at many different scales and, as well as retaining rainwater, they can be integrated into water treatment designs such as Wetland Ecosystem Treatment, or WET systems, to process sewage. See this example of a WET system using swales at a large festival site in the UK which serves 50 people all year round and up to 5,000 people four times a year during the gatherings on site.


Water retentive swales fed by runoff from roofs can be easily replicated by local people with hand tools as specialised equipment is not needed. Treebogs are easy to build and have a 30 year track-record in both temperate Europe and the brittle ecosystems of the Mediterranean. Provided a Treebog platform is mounted at least one metre above the ground, the structure can be adapted to use a variety of local materials and the skills and imaginations of  local people. Treebogs are built using simple hand-tools and can be planted with trees which can be coppiced for polewood - which can be harvested to make more Treebogs. Initially the siting of swales and Treebogs needs input from someone experienced in regenerative design (they should not be located where there is a likelihood of flooding),  but very soon local people gain the skills to ensure they will be located appropriately, will function properly and are able to build more. Local knowledge is important for the success of the Treebogs so that appropriate trees are used. Knowledge sharing and planning with local people is needed to make sure swales, Treebogs and the trees planted around them are properly maintained. 

"I feel that the Treebog has landed successfully in Africa, and that here at Kamyaak they will be looked after and used, meaning that Treebogs have a good chance of wider acceptance both here and in Africa generally. There is a greater opportunity to harvest rainwater from all of the roofs within the compound and direct this water to mulched tree and shrub lined swale ditches all around the compound." - Jay Abrahams, Biologic Design

"We are absolutely convinced about the Treebogs and would like to help other communities to build their compost toilets. We see the results already in our village and are happy to share that knowledge. Just contact us by email or phone." - Aziz from JiwNit


Tel: 00221 772653038


If you would like to know more about Treebogs and water retentive landscapes, or be connected with Jay Abrahams at Biologic Design, contact us here.


bottom of page