Is Recycling Our Poop Key to Sustainable Farming?

Image credit: The Humanure Handbook

From high-tech urine separating toilets, through DIY humanure toilets, to peeing on your compost—TreeHugger is no stranger to the idea of recycling human excreta. Thanks to fellow TreeHugger Matthew, I've just come across a great article that offers a historical perspective on the recycling of human waste, and delivers a compelling case why we need to revive this practice for the sake of future generations. With the threat of peak phosphate looming large (along with such minor concerns like catastrophic climate change and peak oil), it's hard to argue with the idea that we need to keep nutrients cycling within our agricultural systems for as long as possible.

Over at Low Tech Magazine, Kris De Decker lays out the reasons why recycling human ad animal dung is absolutely essential for sustainable farming. De Decker points out that by flushing our pee and poop down the toilet, we are essentially washing these valuable nutrients out to sea, a place where they will remain forever, except for the small amounts we can re-harvest through sea-bird guano or by eating fish. (Assuming we then reuse our waste as nature intended!)

Nevertheless, as I suspect the comments to this piece will show, there is significant fear, resistance and prejudice to the idea of using human waste as an agricultural input—especially on edible crops. De Decker also takes a look at where this resistance comes from, tracing how Chinese cultures recycled valuable "night soil" for centuries with little cultural resistance or problems with disease, while European cities suffered from major epidemics as their streets turned to open sewers. (Night soil was collected in Europe too—just not on the same scale, or with such precision.)

De Decker goes on to explore potential methods of human waste recycling, from the decentralized composting toilet, through vacuum sewer systems, to the spreading of sewage sludge (which he points out often also contains toxic industrial waste products). Ultimately, he says, the most sensible answer is to encourage a more dispersed human population—specifically challenging the notion that suburbia is a thing of the past:

"If cities were smaller and distributed more uniformly throughout farming country, the logistics of returning humanure to farmland would be greatly simplified. Of course, this 'decentralisation' of the human population goes against the notion that densely populated cities are more sustainable than a more uniformly distributed population. The challenge may not be to abandon Suburbia, but to make it more self-sufficient."

More on Recycling Human Waste
Future Food Production Could be Constrained by Lack of Phosphorous
P is for Phosphorous (as Well as Human Urine)
Is Male Pee Better than Female Pee? A Compost Conundrum
How to Garden with Urine