How to make a homemade vermicomposting toilet

There are many aspects to living in a fully sustainable way. One of them is the use of waste that is normally lost in the toilet, despite its potential as nutrients. In Quinta do ValeIn Portugal, where there is a strong permaculture community, they have chosen not to waste anything. To do this, they developed a toilet for vermicomposting. We tell you how they did it so you can take advantage of this technique.

1. Alternatives to toilets in off-grid communities.

The first idea managed by this community was the creation of a dry pit that incorporated a composting system, something that is easy to build and maintain. However, the idea was abandoned because this type of toilet is not to everyone’s liking and, also, with the aim of finding better solutions without sewers.

Thus, the gaze fell on certain experiences developed decades ago by the American Anna Edey and, on this basis, it was chosen vermicompost toilet with cistern, which include a compost container with worms and a filter.

2. Vermicompost toilet with cistern: the concept.

The idea was to take advantage of a conventional flush toilet that, through a drain pipe, emptied into an insulated plastic container. This container must contain a good proportion of worms in its upper layers, in organic material with a high carbon content.

When the reject enters the container, the solid waste remains on the surface to be treated by the worms. On the other hand, the liquids flow through the organic filter material, so that they exit the container to a basic filter which is also rich in carbon, where they are absorbed by plants or transformed by bacteria in the soil.

3. Manufacture of composting toilets.

To shape this toilet, we opted for a plastic intermediate container (IBC) and 1000 liters of capacity.

In the upper part of the container, an access door has been activated by making a cutout in the middle of the strip. This part must be reattached, but anchored to the central opening which gives way to the pipe by screws and an aluminum bar in the frame on each side.

The next step after activating the tank will be to connect a 110-millimeter outlet pipe, as well as dig a trench that will be used for conduction to the filter area.

The reservoir is located just below the toilet, in a shale stone enclosure. When this community built their walls, they added insulation systems to maintain the optimum temperature for the worms (13 degrees in winter and 27 degrees in summer). In the area near the container, polystyrene insulation was chosen. To fill the voids, an expanded clay aggregate was used.

For its part, light corrugated galvanized metal was installed for the roof to facilitate access to the tank. In addition, the cover incorporates the same insulating material as in the previous case.

The grow bed, about 1.5 cubic meters in volume, should have a depth of half a meter, a space in which leaves and wood chips, among others, will provide carbon, in addition to act like an organic sponge. Make sure there is enough space to handle the volume of solid waste from the toilet. The wastewater is channeled precisely into this bed, which flows through a 40-millimeter waste connection system.

Once the system has a water supply and the worms are incorporated into the tank, the toilet is ready for use so that no waste is wasted.

Original project in Permaculture.