Eiffel Over

Tag: CircularEconomy

  • Story of poo

    Some context. When people started visiting Hazel Hill Wood for respite and educational weekends in the early 1990s, there were no buildings. I believe the first structure to be built housed a pair of composting toilets. These were wonderful creations, with hide-like windows that let you gaze out across the wood from your perch high above the long drop—without anyone seeing in.

    By the mid-90s, we began constructing off-grid buildings to accommodate larger and larger groups. With this expansion came more toilets. Today, three of our four accommodation buildings contain indoor composting toilets, each with a different design. Altogether, we now have nine toilets on site. We’ve become a veritable museum of composting toilet design.

    But while our capacity has grown, we haven’t developed a cohesive plan for dealing with all this “output.” Back when only small groups visited occasionally, a pair of long-drop toilets worked perfectly. Between visits, there was plenty of time for the poo to break down.

    As the charity has grown, though, so has the intensity of toilet use. With less time for natural decomposition, we now have a mounting problem—literally.

    Staff must increasingly deal with shifting shift —unpleasant, hidden work that highlights a gap in our design and planning.

    But here’s the thing: our story of poo could be so different. Poo is, after all, one of the clearest examples of a waste stream that can be transformed into input nutrients for new growth. This is a fundamental principle of self-sufficiency, permaculture, and regenerative design.

    What if we could close the loop on poop, turning it into a productive part of our nutrient cycle? And what if the process—given how beautifully it illustrates these principles—were well-designed, pleasant to manage, and something visitors could learn from?

    So, my ambition is to rewrite the story of poo at Hazel Hill. It starts with improving the design of our most unpleasant-to-operate toilets and refining the process of transporting “humanure” to the composting bays.

    As for what we’ll do with the composted material? The leading idea is to use it as manure for a fruit tree orchard—which doesn’t exist…yet. But hopefully, one day, we’ll be able to enjoy the literal fruits of this labour.

  • Plenty more fish in the sea

    Yesterday’s post on the fish écluses on the Île de Ré speaks to the idea of creating straightforward connections between the resources that humans need to live and thrive. 

    As engineers (and other humans) we need to find ways to harvest the materials and energy we need in balance with what the living and mineral world can sustain. So to help us understand how this can work I’m sharing Donella Meadows’s example of fish stocks to help see how humans can live as part of a sustainable system of supply.

    Meadows’s model concerns the local fish population in an area of sea. Left to its own devices, the fish population is stable because there is only so much food to go around. Too many fish, less food per fish, some fish die. Too few fish, more food per fish, they reproduce more. This feedback loop stays in equilibrium around a mean.

    Now, the local fishing fleet gets involved. By harvesting a small number of fish, the population goes down, increasing the reproduction rate of the remaining fish, and the population returns to what it was. Fish too much, however, and the fish are further apart. Fish that are further apart take longer to reproduce! And so for a while, there are few fish, the nets are empty and the boats go back to port. During this time the fish population recovers, and eventually the boats can go back to sea.

    This simplified model beautifully illustrates how humans can harvest what they need while still living within the ecosystem’s limits.  The key characteristics here are a living system that regenerates itself – the fish; and a feedback loop between supply and those doing the harvest. Simply, when the catch is too low, the boats go home. 

    This feedback loop between supply and harvesting is what interests us in regenerative design. It is what allows us to harvest abundance, and even create abundance, all while living within the ecosystem’s limits.