Dry toilet

Permapreta® is a compact dry toilet system design, all in one unit.

The main system of Permapreta® resides in the operation of the tank, of which we have two different sizes. Through the main hole, where the toilet is placed, the excrement falls to the grates where a bed of microorganisms and red worms (Eisenia foetida) await them. They are in charge of handling the faecal matter to convert it into hummus that will fall on the conic part of the tank.

As you can see, apart from the main aperture, the tank has more holes, smaller in size (100mm). This design facilitates air extraction tube colocation. We will choose one of them to connect the hybrid air extraction system (the other one is not going to be used). The third hole (125mm) reaches under the grids, where we will introduce the endless or extraction aspirator, to empty the already processed hummus two years after the first use and yearly afterwards. Therefore, with Permapreta, there is no need to either disassemble the system or paralyze it.

Urine-diverting toilet:

Urine separation is essential in this system. From Permapreta® we have designed a ceramic toilet and another one in polyethene material, with studied dimensions and sizes for perfect operation.

Besides, Permapreta toilets are designed to have the option to be connected to a house water circuit, with the complimentary installation of a push-button. It pours about 300 ml of water over the urinal part for cleaning purposes and diluting the urine.

The toilets can work independently, as the tank does, both products can be built into other dry toilet systems.



No need of any specialist for regular maintenance. It does the faecal transformation by itself, in so doing you avoid any other collection system for it.

First uses

Upon installation, the preparation of spray-active microorganisms and the mixture of straw, bokashi and charcoal are added. Red worms (Eisenia foetida) are added one month after the first regular use, and half a month later, a handful of pyrolytic charcoal (biochar) is added.


The microorganisms are sprayed daily, depending on the frequency of use. Every 15 to 30 days, vegetable remains from the kitchen or straw are added through the main pipe (toilet), which collaborates in the activity of efficient microorganisms. They must have been treated with the fermentation process in the bokashi bucket.

Cleaning process:

As a dry toilet Permapreta cannot be cleaned out in the same way as the usual systems. But this does not prevent good hygiene of the Permapreta system and its health safety.

From Permapreta we recommend the “eMC LIMPIADOR®” cleaners, this concentrate will make it shinier and disinfected if it is sprayed on the toilet. The eMC® cleaner can be prepared in a sprayer, in a dilution of 30 to 60 ml for each litre of non-chlorine water.

EMC® Concentrated Descaler contains beneficial microorganisms that help break down dirt for easier cleaning. Surfaces stay clean for longer, thanks to its antistatic and non-stick effect, which prevents dirt from being attracted to surfaces. In addition, beneficial MCs enhance the effectiveness of the other ingredients, and control pathogens so that they cannot spread.

** These products do not cause any damage in contact with the skin


The Permapreta® tank works both for a dry toilet and for composting process. If you choose the composting option, the main entrance hole is no longer covered by a toilet, instead comes with a special lid to keep it closed.

The rest of the outputs fulfil the same functions as in the dry toilet. A hole for extractions purposes and two small circles for the ventilation system. Those two circles, one on each side, to have greater availability when installing it, in the case while assembling the set we find an obstacle to one of the sides.

Ventilation system

Hybrid air extractor:

Another project that has opted for Permapreta® in its waste management is Biosur Insectarios, where a Permapreta® dry toilet complete with urinal and sink has been installed for the use of its workers.

Axial fan extractor:

Complementary system to the previous one to optimize the extraction of humidity in too long ventilation runs or absence of an adequate wind regime.


Installation process:

Permapreta® can be buried or on a structure.

It must be seated correctly and well levelled to avoid future movements. The tank must be as close to the toilet as possible, leaving only the slab as a separation. It is important to place tie rods to avoid deformations in the tank in the process of filling the lateral spaces. The good sealing of the lid and the connection pipes with the toilet, ventilation and extraction is essential to avoid the incorrect operation or the entry of insects or water.


The installation on a structure is the appropriate solution for when it is placed in a basement or warehouse, and we install the bathroom in the upper room. Also here, the distance between the toilet and the tub must as close as possible.

If we are burying it on flooded land, the subjection of Permapreta with the structure is the most recommended option.


In this section you can download the user and installation manuals:

Find Us:

Polígono el Pont.
Avenida España nave 32

Call Us:

(+34) 629034278
(Jose Vicente)

(+34) 642330223

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