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Figs for picking from our loo with a view

This is the view from our loo.

fig tree

It is one of the advantages of rural life, that you can have a loo with a view.  Figs are now in season, and you can sit on our loo and spot the ones that need picking. Which is a useful thing because figs don’t ripen well when picked green (the main reason they’ve never made it into the standard supermarket array), they ripen daily, and they’re best eaten straight away.

Our loo is a red manure worm processing system, and the resulting worm castings end up in an underground trench that the fig tree’s roots can get into.  That may, or may not,  have something to do with the fact that this year is turning into a very good year for fig harvesting. It’s a relatively new system – we’ve given up on the imperfectly designed composting toilet that always required a bit too much attention and maintenance to work properly on the cool south side of the house in our sub-tropical climate.  The new worm processing system should, in theory, work much better.

I always think that “composting toilet” is a bit of a misnomer.  Compost by rights is a compound that contains big, stable molecules of humic acid created by a particular kind of thermophilic bacteria.  The particular bacteria that make it like about three times as much carbon in their diet as nitrogen, an environment that is moist but not wet,  batch not incremental feeding, and nice insulation to keep warm.  Manure (human and other animals) is nearly all nitrogen rich compounds, much too wet, and you don’t get a batch of it all at once.  Most of the designs I see work on the principle of drying and aging rather than true compost making.

Anaerobic bacteria, the kind that make biogas, like a nitrogen rich wet environment. I see a few designs around these days for household scale biogas digesters and I suspect that could be the technology of the future.

But the other creature, and the one we’ve targeted, is red worms – Eisenia foetida and Lumbricus rubellus species, commercially used to process pig manure.  We were seeking a design that used no water – we’re on tank water, and in a drought year it is always a toss up whether to conserve water for possible fire fighting, spend it keeping trees alive or the garden producing, or let it go to environmental flow.  Flushing a toilet doesn’t get a look-in.

We were also seeking a design that used no or very little power. Nowadays we now have 4.5 kva of off-grid solar power and most of the time we can be completely profligate with spending it – put the electric bread oven, the slow cooker, the stereo, the washing machine, the pool pump and every light in the house on all at once. But I am so used to being frugal with power I can’t bear the idea of wasting it!

It had to cope with urine, cycle nutrients, take virtually no maintenance, and be salubrious enough for visitors used to white porcelain.

All that, and, very importantly,  a view.

{ 4 comments… add one }
  • Angus February 2, 2016, 12:35 pm

    No details of the loo though! 😉 Is it a bucket system? Or a hole in the floor to the trench? Do the worms cope with the direct poo? Do you add carbon-rich things (sawdust, straw, etc) to the waste?

    I’ve recently bought a urine diverter, and am going to make it into a bucket-in-a-box “composting” toilet, so am thinking about this atm..

    Cheers, Angus

  • Linda February 2, 2016, 1:08 pm

    Hi Angus, it’s a 300 mm pipe, straight down from the seat for 2 metres to the ground, then 12 metres just buried (not too deep), on a 30 degree slope. It has weed mesh over it and lots of holes in the underside. The bottom comes out of a bank and has a screw cap with a little 12v fan in it. There is a hose fitting with a gate valve that can be used to drain off liquid but there hasn’t been any to drain off – it soaks in. The pipe had a metre bed of worm bedding with 4000 worms put in it at the top end before it was all connected up. The straight down section had 30 cm of compost put down it first, then we started using it. We add a sprinkle of ag lime each use. We plan the resource recovery to happen via the fig tree and bananas with roots in the zone. In 10 years or so though, we may be able to recover worm castings at the bottom. The system so far has worked fine through a winter and a summer and now coming into a wet season. It’s a bit hard to tell how the worms are faring. If I were redesigning I would add an inspection pipe with a screw fitting at the top end of the 30 degree pipe, so as to be able to check on the worms at the interface, so to speak.

  • Angus February 3, 2016, 12:24 pm

    Hi Linda,

    Wow — that’s great. I guess the seat needs to seal pretty well to prevent odour? Is the idea that the 12V fan creates a negative pressure in the pipe so that air is drawn into the toilet when the seat is open?

    Nice design!

    Thanks, Angus

  • Linda February 3, 2016, 3:02 pm

    It’s just an ordinary wooden toilet seat, mounted in a sturdy wooden coffee table wth a hole cut in it. The fan draws air so ot doesn’t smell, an also to provide fresh air for the worms. I also spray painted the inside of the vertical pipe with black matt paint so you can’t see down it.

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