Combined systems: bioanthroponics
Anthroponics turns human urine into a nutrient solution; bioponics does the same with compost, bokashi, biogas slurry and plant waste. Each source on its own is incomplete. Urine is rich in nitrogen but short of some elements a crop needs; vermicompost and bokashi leachates carry potassium, magnesium, iron, calcium and phosphate but less nitrogen; wood ash brings potassium, calcium and magnesium and raises pH. Bioanthroponics is PonicLabs’ name for combining these streams into one recipe, so that the shortcomings of one source are covered by another.
The recipe we tested (2021)
In a home experiment in Malmö, Sweden, a mixed nutrient solution was built from four inputs and two pH correctors:
| Input | Effect on pH | Main contribution |
|---|---|---|
| Aged (volatilised) urine | basic | ammonium, later nitrate after nitrification; some K and P |
| Vermicompost leachate | basic | nitrate, sulphate, potassium, magnesium, iron, phosphate |
| Bokashi leachate | acidic | ammonium, potassium, iron, phosphate, calcium, magnesium |
| Wood ash | basic | potassium, magnesium, calcium |
| Phosphoric acid | acidic | phosphorus, used to bring pH down |
| Hydrated lime | basic | calcium, used to bring pH up |
The weekly dose for one small system was about 500 mL of aged urine, 200 mL of vermicompost leachate, 200 mL of bokashi leachate and a few spoonfuls of wood ash, with phosphoric acid for pH. The mix passed through a small biofilter (expanded clay, gravel and used moving-bed carriers, with a small pump lifting water from bottom to top for aeration) before reaching the plants.
Two passive growing systems were fed from it: a bucket of coir and perlite (50/50) sub-irrigated through a feeding tube, and a “pot-in-pot-in-tray” variation of the Kratky method, where a smaller inverted pot inside a larger pot leaves a moist air space above the solution. Large-leaf basil in the bucket grew without visible deficiencies; the pot-in-pot system came close with less growing medium.
What we took from it
- A combined recipe covers the nutritional gaps of urine alone.
- Once the solution has passed a biofilter, passive (non-circulating) systems can run on it.
- The next question is whether the nitrification step can be skipped: plants take up ammonium directly, and a recipe that works without a biofilter would be simpler still. That question led to MUNCH.
Sources
- Sanchez, H. (2021). Bioanthroponics. Video and transcript on the PonicLabs YouTube channel.
- The anthroponics and bioponics reports behind each input are listed on Published research.