A humanure compost bin is built from stacked pallets, woven branches or earthbags about 1.2 m × 1.2 m × 1 m, which holds 1.44 m³, above the 1 m³ minimum for reliable heat. Build three, one to fill, one to age and one to finish, each with a removable front for emptying, a roof against rain, a base that does not leak into the ground, and a site well away from any well, spring or stream.
Part of Composting Toilet Systems
A compost bin is the enclosure in which emptied toilet buckets are stacked, covered and left to heat and age. It must hold the heat of a pile of at least 1 cubic metre, keep rain out and keep contaminated liquid in.
Bins Receive Human Waste Only
The parent page says the bucket system needs dedicated bins that receive humanure exclusively and not kitchen compost, at first. Keep them apart from the kitchen and garden compost so that a mistake with one never contaminates the other.
What The Bin Must Do
- Hold at least 1 m³. A smaller pile loses heat faster than it makes it (Thermophilic Decomposition). 1.2 m × 1.2 m × 1 m = 1.44 m³.
- Keep rain off. A roof or cover (tarp, sheet metal) stops rain from cooling and waterlogging the pile.
- Keep animals out. Close fittings and a lid or heavy cover.
- Open at the front for emptying, with a removable board or panel.
- Not leak. Liquid from a humanure pile must not reach groundwater or a stream.
What You Need
- Walls: stacked pallets, woven branches or earthbags (the parent page’s three options)
- A roof: tarp, sheet metal or boards on a pitch so rain runs off
- A base: packed earth with a 15 cm bed of dry straw or sawdust on top, on ground that is above flood level
- A cover supply: straw, leaves or sawdust next to the bins
- Insulating liner: straw or cardboard inside the walls if you use gappy pallets
Method: Build, Site, Seal
Step 1: Site it. Place the bins well away from wells, springs and streams. Source Protection lists compost piles and manure heaps within 30 m of a water source as a high contamination risk, and notes groundwater can carry contamination farther than the surface suggests. Choose ground downhill of any water source and above the flood line. The distance is a rule of thumb that assumes the soil between the bin and the source filters what moves through it; it gives no protection in fissured rock or karst, where water travels quickly through cracks, and there no distance is safe without a measured flow path.
Step 2: Prepare the base. Level a 1.2 m square, pack it, spread 15 cm of dry straw or sawdust. This soaks up liquid at the bottom.
Step 3: Raise the walls. Stand pallets on edge and tie them at the corners, or weave branches, or stack earthbags. Make the front a separate panel of boards that slides or lifts out.
Step 4: Line it. Pallet gaps lose heat. Line the walls with straw or cardboard; keep enough openings that air can still reach the pile.
Step 5: Roof it. Slope the roof away from the front so rain does not run into the bin, and extend it past the edges.
Step 6: Label it with the date it starts filling.
The Three-Bin Cycle
| Bin | Job |
|---|---|
| 1 | Currently receiving buckets |
| 2 | Full, closed, heating and ageing |
| 3 | Finished or curing, or being emptied for use |
Worked example for four people: a 1.44 m³ bin filled with 920 to 1,460 L of material per year takes 1.44 ÷ 1.46 = 0.99 to 1.44 ÷ 0.92 = 1.57 years to fill. After it closes, it ages for a further year, so a bin is useful about 2 to 2.6 years after it opens. Two bins ageing in turn and a third as a spare covers that cycle.
Common Mistakes
- Pallets of unknown origin. Pallets stamped with the letters “MB” were fumigated with methyl bromide, as I recall; avoid them and any chemically treated wood. Heat-treated (“HT”) pallets are the usual safe choice.
- A bare earth floor with no absorbent bed. Liquid soaks into the ground.
- No roof. The pile goes cold and sodden.
- Siting it by the water supply to save carrying.
Safety
The bin holds untreated human waste and leachate
Keep children and animals out. Wear gloves and wash hands after every bucket tip. Sharp nails and splinters in pallets mean cuts, and a cut that meets faeces can become a serious infection; wear gloves and clean any wound at once. Do not climb into a bin or stand on a pile.
What’s Next
- Learn next: Monitoring Temperature & Progress — know whether the bin is working
- Combine with: Simple Bucket System — the toilet that feeds it