Using urine to heat homes

URINE, THOUGH distained by modern society, was once surprisingly useful stuff. Street-facing laundries in ancient Rome had pissoirs attached to them, to encourage passers-by in need of relief to provide, free of charge, a raw material which was then fermented into a degreasing agent. Urine also found employment as a mordant, to assist in the dying of cloth—Scottish tweed was once notorious for smelling of the stuff when it got wet. And urine was, too, a source of potassium nitrate, one of the ingredients of gunpowder.

Now, Chen Wei-Shan of Wageningen University, in the Netherlands, thinks he has found yet another use for urine—and one relevant to today’s needs rather than yesterday’s. He plans to employ it to create heat without fire from waste wood.

Burning wood is a good source of heat and it can be seen as sound from the point of view of greenhouse gases. That is because the carbon dioxide released into the atmosphere came thence in the first place, and would return there anyway if the wood in question were simply allowed to rot. But wood fires also bring environmental disbenefits, for they give off sulphur dioxide, carbon monoxide and other noxious gases along with that CO₂.

Researchers have therefore been looking for ways to release wood’s latent heat by composting rather than combustion....