Thanks! Had never heard of Milorganite. My interest is purely one of curiosity, specifically how waste might be recycled in a Mars or Moon colony. The Chinese regenerative life support project Lunar Palace 1 claims 41% nitrogen recapture from solid waste, using a "bioreactor" i.e. flippable compost bin:

https://en.wikipedia.org/wiki/Yuegong-1

https://pubmed.ncbi.nlm.nih.gov/27912029/

It's unclear from the published results whether the crew ate food grown from this compost, or just measured the output's nitrogen content.