RegisTree Composting Facility

What we built

Replaced a timber-and-tarpaulin structure with a permanent, ventilated building on a concrete slab, and built an on-site composting toilet piloting safe humanure management.

Building Humanity partnered with RegisTree, a Kenyan community-led composting organization, to design and build a permanent, climate-resilient composting facility in Watamu. The project replaces RegisTree's makeshift structure with a weatherproof facility designed to expand its black soldier fly composting operation, while piloting an on-site composting toilet as a model for safe, ecological sanitation. It will also expand waste and sanitation education, support up to 500 local farmers with compost and larvae, and create economic opportunities for community members, particularly women.

A three-year commitment

1. Year one (complete). A permanent, ventilated building on a concrete slab replaced the timber and tarpaulin structure that had nearly cost RegisTree its entire crop of larvae when the roof leaked. An on-site composting toilet was built alongside it, piloting safe humanure management.
2. Year two (next). Taking sanitation out into the community: a multi-stall composting toilet at a public site, and continued education and monthly service projects.
3. Year three. Expansion and scaling, with additional composting facilities and toilet locations chosen from what the first two years teach us.

Why Kilifi County

Kilifi is among Kenya’s poorest counties. It ranks in the top fifteen nationally for open defecation and the top ten for diseases caused by poor sanitation. In 2023–24 alone the county health department recorded 104,618 cases of childhood diarrhoea in health facilities. Soils lack the nutrients and organic matter needed to yield good crops, and weak waste collection has left visible illegal dumping sites.

RegisTree began in 2022 as a mangrove restoration initiative and moved to food waste composting in 2023. With under $4,000 of grant funding they launched a black soldier fly composting project, completing their first pilot in early 2025. Black soldier flies handle all food waste, including oil, meat and dairy, and yield larvae for poultry and fish operations. They have buyers for all the compost and larvae they can produce.

2026 Project Update

Due to geopolitical instability, we made the decision not to bring volunteers to the build this year. Instead, Leigh Lane, Director of Africa Sustainability & Community Impact and Board Member, traveled to the project site to observe progress firsthand alongside RegisTree, assess the status of the build, and identify any remaining needs or opportunities for support. This visit allowed us to maintain oversight of the project while prioritizing the safety of our volunteers.

To learn more about the progress achieved during the first year of the project, we invite you to download and review our Year 1 Narrative Report and Year 1 Financial Report, which provide a detailed overview of project activities, outcomes, challenges, and financial performance.

Developing a New Kind of Volunteer Trip

Building Humanity is developing an immersive, hands-on learning experience in Watamu, Kenya, where students will work alongside RegisTree to explore the circular economy in practice. Through direct engagement with RegisTree’s waste management operations, students will learn how food waste is collected, processed through Black Soldier Fly composting, and transformed into valuable resources such as compost and animal feed. They will gain firsthand insight into how a local social enterprise is turning an environmental challenge into an opportunity for sustainable livelihoods and community development.

Rather than focusing on physical construction, this program will center on building knowledge through practical experience, conversations with local practitioners, and observation of each stage of RegisTree’s circular economy model. Building Humanity is developing an itinerary that connects these hands-on experiences with broader themes of sustainability, waste management, and community-led innovation. Students will leave with a deeper understanding of how circular economy principles work in practice and how locally driven solutions can address environmental challenges along Kenya’s coast.

The skills we are looking for

If you're a professional interested in volunteering on our 2027 trip, we'd love to hear from you. Below are the skills and expertise we're currently seeking. Please note that the itinerary for professional volunteers may differ from our standard trip schedule. In addition to project work, there may be opportunities to lead workshops or mentor local community members interested in developing these skills.

• Composting toilet specialist: to assess site conditions, guide construction and train local staff on long-term maintenance.
• General construction: carpentry, masonry, basic repairs and site preparation.
• Medical: Building Humanity keeps CPR and first-aid certified staff on site, and additional medical knowledge on the team is an asset.

Building Something More

Alongside building knowledge, volunteers will run a STEAM day with Friends of Arabuko-Sokoke Forest for schools inside the last remaining dry coastal forest in East Africa. Six to ten activity stations will let children explore science and engineering through experiments, crafts and projects, working with Junior Rangers who are learning about elephant behaviour, biodiversity and land restoration. Volunteers will also join community engagements with two local NGOs, COBEC and Dabaso Youth for Green Future to learn about mangrove conservation and creating sustainable alternative livelihoods for Watamu community members.

Year two dates and costs have not been set. Contact Erin Colshan at info@buildinghumanity.org to register interest.