Last year I wrote about our installation of a vermicomposting flush toilet – a worm composting system for a conventional flush toilet – in the outhouse for the wee house. It was all ready and set to go for a good while, minus the worms, but we couldn’t start using it until we had a water supply to the wee house since there would be nothing to flush with until we did.
With the completion of the quinta’s water storage and distribution system in February, I could at last commission the system.
To ready the tank for its purpose, I filled it half way with a large amount of pine woodshavings, dead bracken and leaf litter, layered in that order from bottom to top. I then added a 50-litre bucket of partially-processed compost from the compost heaps, along with some fresh kitchen scraps.
I also filled the growing bed with wood shavings to a depth of about half a metre. About the third of a tonne in all. This is to provide an organic sponge and carbon reserve for the liquid draining from the tank and was a great way to use all the shavings from the timber-framed grey water-processing greenhouse we are building the other side of the quinta.
On top of the shavings, I laid a branching system of 40mm waste pipe, drilled at regular intervals and sloping slightly downhill to allow the liquids draining from the tank to spread evenly through the shavings.
The pipes were loosely wrapped in horticultural fleece to prevent clogging of the holes by the shavings.
More shavings were laid on top of the pipes, then the bed was backfilled with topsoil and planted with a lemon tree. More nitrogen-loving plants will follow.
The plan was to get the initial worm population from a friend’s piles of horse manure – the last time I collected some manure from them, the piles had been full of tiger worms (Eisenia foetida). Not so in February. I found only half a dozen or so in the cold, rain-soaked heaps, so the only option was to buy some online. With the Portuguese mail service being what it is, I was a bit concerned about this option, but I ordered a kilo of tiger worms from a UK worm supplier and crossed everything I could cross that they’d be OK.
It took 10 days for them to get here. They arrived sluggish and slow, but at least most of them appeared to be still alive. Just. I emptied them into the worm bin and left them a week to recover and feed before starting to use the toilet.
The section we removed from the top of the IBC tank fits neatly back into place before being covered with a sheet of polystyrene to help keep the worms within their preferred temperature range of 13-27°C. The hinged metal roof is also insulated with polystyrene on the underside.
So finally we have a working flush toilet on the quinta. During the initial fortnight or so after we started using it, there was a slight smell from the worm house, but that disappeared within another week and there’s now no detectable odour at all. Not even the dog seems to pick up anything. Which is just as well, as we’ve now completed a patio dining area immediately above …
November 2016 The toilet has been working for 2 years now. It’s generated a lot of interest. My local municipality are planning to install vermicomposting units based on this system in local villages. The first was commissioned in July 2016. You can now legally use this method of sewage processing in this region. I have also created a new website with full details of the system, it’s design, construction, maintenance, and more besides, including a forum. The aim is for the site to become a repository of community-sourced experience with installing and operating this system.