Last Saturday and Sunday, I was a student in the Milkwood Intro to Permaculture Course, run by the excellent Kirsten and Nick (aka Cicada). The above picture is of a flow chart a few of us knocked up during the course, as part of an exercise to hammer home how inter-connected everything is.

Since the course, I haven’t been able to stop talking shit. Literally. My girlfriend is bored shitless. Etc etc. What I mean is, the thing from the course which made the deepest impression on me, is the idea of shit as a resource.

Nick:

The crazy thing is, that we take one of our most precious resources – our own shit – and we mix it with another of our most precious resources – clean drinking water, and we flush them both away into the ocean.

Shit as a precious resource? Yeah man, human shit. You can compost it and put it back in the garden to grow next year’s vegies.

Ignorantly, I had thought this was a sort of taboo in human societies. We dump chook poo, horse poo, cow poo etc (not really dog and cat poo though?) on our vegie gardens, and they really help things grow better. But up to now, I believed human poo was a bit too close to home – doesn’t that shit cause diseases?

Not so, according to Nick and Kirsten, who described the process of composting their own for one year, before putting it around their fruit trees.

The whole concept of permaculture (at least, the bit that made a strong impression on me) is about “energy cycling”. Energy tends to move from a useful to a non-useful state. If we harness the energy released from one process, and use it again, we can keep it cycling round a bit longer before it leaves us for good.

When you think about vegie gardens as a “sustainable” thing, you gotta consider “inputs” and “outputs”. (Or “imports” and “exports”, as Nick put it). Ideally, you want to keep both imports and exports to a minimum. The sun, luckily, and rain when it comes, are “free” imports!

So you might be harnessing the energy of the sun – the plants transform it through photosynthesis, and draw nutrients from the soil, the air, and water. But as soon as you eat those vegies, and subsequently shit down the loo, you are exporting a whole lot of valuable nutrients from your system, which could have been kept local and re-used next time around.

This thought has been haunting me all week, with grim regularity…

Now, this is all very well when you live out near Mudgee. But how could you harvest human poo (and wee) in the city? Especially when you’re living in a rental place, and the landlord won’t even install a double-flush, let alone a composting shitter?