Photos © Craig Mackintosh
You’ve heard the Zaytuna Farm composting loo story before, but since this is the first time I’ve personally seen ‘the great chamber changeover’ take place myself, during one of my own visits, I thought I’d share the tale once more.
The PRI’s Zaytuna Farm composting toilet setup utilises the Farralone (230kb PDF) dual-chamber system. It’s not a complicated affair, and it works a treat. For the… er… end user, utilising the system is as easy as making your delivery, and following that up with a correspondingly appropriate sized scattering of carbonaceous material, like sawdust. The chamber then piles up with layers of nitrogen-rich human waste and carbon. Anyone who understands the ABCs of composting knows what the result of this will be. And, should the loo ever become a little smelly, it’s simply because you’ve been adding insufficient amounts of carbon (sawdust, dry leaves, etc.) — enlarging the carbon additions will promptly address the issue.
When a chamber can’t take any more ‘contributions’, to use Geoff’s terminology, it’s closed up and left to sit for a few months. Our little microbial friends work quietly and busily over this period, working magic with our muck, in a way that only they know how, while deposits continue in the adjacent chamber.
The interesting thing is, no matter how much you emphasise to students and interns how well the system works, when the day comes to actually empty out a full chamber — even when having been left to ‘mature’ for a full three months — the lead-up to the event is always accompanied by a relatively high degree of trepidation. When the day arrives, and Geoff reaches to open the chamber door, students tend to stand back at a ‘safe distance’, wrinkling their noses in expectation, and almost cringing as the door swings open….
But then, mental "eww"s turn into verbal "ooh"s, and the dreaded moment turns into a non-event….
Geoff promptly grabs a shovel, and leads the way — lifting out shovel after
shovel of nice, crumbly looking material — while the students begin to edge closer.
The compost is emptied onto a trailer, before being taken to get spread thin and
layered with mulch. After resting on and under mulch for a while it is then
hot-composted, before finally getting utilised on the farm.
After seeing the rather benign looking material, and Geoff’s indifference about the situation, the students begin to throw caution to the wind and jostle to be next on the end of the shovel. (I mean, who wants to be last?)
At Zaytuna farm, in many ways, it’s incredibly satisfying to know that our most basic needs are met in a passive, carbon neutral (even positive) way, through sensible, appropriate permaculture design. This is especially true when it comes to that most maligned of human by-products — a material we normally, and strangely, mix with pure, clean water, so as to enable us to transfer it into a pathogen-rich, centralised network, before sending it out, at great expense, to pollute our oceans, or before we (insanely) invest enormous amounts of energy trying to purify again…. The other big ‘strategy’ is to simply let it pile up underground, to slowly leach into our landscape and water tables.
When you consider that clean drinking water is of more value than gold to many of the world’s inhabitants, it should be regarded as obscene to be crapping in it!
If this dual-chamber system can handle the many contributions from a very steady stream of students and interns, it can so much the more handle those from a typical home situation.
At the PRI’s Zaytuna Farm our most basic human functions not only leave precious water completely untainted, but another significant plus is that soils are regenerated through the subsequent cycling of nutrients and minerals. Top of the critical nutrient list is phosphorus — essential for all plant and animal life, and a growing concern worldwide. If we harness the potential of nutrient cycling through composting toilets, then the Peak Phosphorus dilemma would become a non-issue.
When I consider the simplicity and logic of such a system at this, the more absurd our massively expensive municipal installations seem.
Talk about turning a problem into a solution!