Help Us Turn Pee into Food at Osire Refugee Camp
Hi, I’m Gert, a researcher at the Namibia University of Science and Technology.
With colleagues from the Swedish University of Agricultural Sciences, we’ve developed a fully passive way to turn urine into safe, carbon-negative fertiliser, using only solar heat and natural ventilation.
No electricity. No moving parts. Just sunlight, airflow, and a little smart design.
The Problem:
Osire Refugee Camp in Namibia is home to approximately 9,000 people, and just a week ago they welcomed another 70 families. It’s one of Africa’s most self-reliant camps, self-funding the education of 1900 children and growing its own food to feed the camp. Unfortunately, fertiliser is expensive. Without it, food yields drop and incomes shrink.
The Solution:
We’ve already built and tested a small passive solar evaporator that can dry 5 litres of urine/day per m² (I'll share some typical data charts).
Now we’re scaling up to build a larger fully passive system at the school – only solar heat & ventilation, no electricity.
- No ventilator – cutting costs in half and removing the only moving parts
- Brick construction with a multiwall polycarbonate sheet for insulation
Target capacity: 200–500 litres/day (40x - 100x increase)
For this first stage, we'll divert urine from the urinals at the school, which will yield approximately 500L of urine per day, and produces approximately 15kg of fertiliser per day.
We'll start with citric acid (because it's easier to handel):
25kg citric acid costs N$692.60, roughly U$40, and a minimum of 200 operational day's a year.
At 10g of citric acid per litre for stabilisation:
- 200L/day = 2kg citric acid (U$40 = 20 days) ~U$400/year running cost
- 500L/day = 5kg citric acid (U$40 = 5 days) ~USD $1,600/year running cost
Once we're happy with operations we'll switch to sulphuric acid (which is more difficult to handel but significantly cheaper):
45kg citric acid costs N$386.20, roughly U$22.
At 2g of sulphuric acid per litre for stabilisation:
- 200L/day = 400g sulphuric acid (U$22 = 112.5 days) ~U$40/year running cost
- 500L/day = 1kg sulphuric acid (U$22 = 45 days) ~USD $100/year running cost
Fertilizer production:
- 200L/day x 200 days = 30g/L x 40,000L = 1,2 tons of fertilizer annually ~ N$19,000 / U$1100
- 500L/day x 200 days = 30g/L x 100,00L = 3 tons of fertilizer annually ~ N$48,000 / U$2,750
Even at 200L/day, the system pays for itself in under 2 years.
Why It Matters:
More fertiliser means:
- More food for the camp
- More income for the community
- A scalable, self-sustaining model for other refugee camps and informal settlements
Want the full story — including the geopolitics, tech, and why pee might just help save the planet?
Read my article here: https://www.linkedin.com/pulse/taking-sustainable-design-network-5zbke/?trackingId=S4DxcL2tf6EZaQwfhGFk4g%3D%3D
Or watch a presentation I gave:
What We Need:
We’ve already secured N$50,000 (U$2,850) for construction.
Your donations will cover:
- Insulation materials (multiwall sheets)
- Acid for urine stabilisation
- Storage containers for urine collection
Our target is USD $2,000 to build Osire’s system this year.
Be Part of the Flow:
Every flush is part of a bigger cycle, connecting people, food, and survival. At Osire, that cycle can mean full plates and secure livelihoods.
Donate today and help us turn waste into hope.
If you can’t donate, please share this campaign, it really makes a difference.
Organizer
