Newly completed composting toilet
This is an analysis of a humanure composting toilet designed and built at the Panya Project in Mae Taeng, Thailand. Humanure toilets are a very effective, easy, cheap method of creating a resource out of what our conventional society views as waste. A humanure composting toilet allows feces to break down into soil by adding sawdust to the chambers after each ‘use’. After six months of breaking down, the humanure transforms itself into fresh soil which can be used for the garden.
The previous toilet at the Panya Project had a wooden floor structure. Over the course of two years, the floor rotted from the moisture in the chambers. To avoid this problem again, the new toilets were designed using steel beams and cement panels. These redesigned humanure toilets should last for many years.The last design also incorporated an elaborate roof design. The roof and general design of the toilet was going to be simple.
The old composting toilet
The design of the toilet is four toilets/chambers with a corridor in the middle. Each chamber, and each stall, measures 2m x 3m and the chamber depth is 2m, making the total cubic area of the chamber 9m2 (2x2x3). Because of the gradual decomposition of humanure, the toilet could possibly never fill up. But if and when they do, they will be able to be reused indefinitely.
We first dug footers and filled them with concrete. Then we hung string lines and started laying bricks, making sure each row was straight and level.
Once the walls were 2m high, we set steel beams, painted with rust oxide, in mud on the top of the wall. This served as a guide to level the floor panels. On top of the beams, we then laid 2.5 meter long reinforced concrete panels to cover the floor. When we first laid the panels on, they broke in half. So we installed two more steel beams to support the weight of the panels.
We then extended each of the corner posts of the toilet another two meters. These pillars support the roof frame.
Then we framed the rooms with bamboo poles, and wired a wattle frame out of bamboo for cob walls.
The old toilets had a wooden platform to ease the climb up to the toilets. We raised the platform, removed the old concrete pillars from the ground and relocated them to the front of the new toilets.
Once the platform was in place, we moved the sitting toilet to the new toilets, hung some curtains and started using them!
How we used Permaculture principles and ethics
- Observe and interact
- Obtain a yield / Produce no waste
- Apply self-regulation and accept feedback
- Use and value renewable resources and services
- Concrete panels — 32 x 220 = 7040 baht (materials)
- Steel — 2500 baht (materials)
- Roof — 8000 baht (materials and labor)
- Tiling — 3000 baht (materials and labor)
Monitoring and Evaluation
So far the toilets are in working order – we have one ‘sitter’ stall and one ‘squatter’ stall. We decided to call the toilets ‘The Shateau’.
Two stalls will be open for use at a time. Once they fill up, we’ll switch to the other two and let the piles decompose.
The upkeep of this system
- Every few days — poo stacks up in the middle of the chamber. So we use a long stick to level the heaps.
- Once a week – get sawdust from a wood sculptor in Baan Mae Jo village and buy toilet paper.
- When a chamber fills up – move the curtain to another toilet and put up a sign to say the toilet is not in use. Make a sign dating when the chamber was full. Then mark a date six months from then, when the compost will be safe to use.
- When “Eww” Turns to “Ooh!”
- Life at Zaytuna: Closing the Loop
- Food Forests, Part 4: Humanure (black water)
- Humanure Handbook – Free Download
- Phosphorus Matters
- Phosphorus Matters II – Keeping Phosphorus on Farms