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How to build (and use) a cacajón (literally a poo-box) according to a cacologist

How to build (and use) a cacajón (literally a poo-box) according to a cacologist

Posted by on Jan 20, 2013 in all posts, Mexico, Universidad de la Tierra | 1 comment

My first, major (and classy) blog entry

My first post was supposed to be a reflection on why I am here and some of the first things I have learnt. This post will eventually come, but for now I will be writing literally about how to bring your shit to life, or even better said, how to enliven your shit.

The reason why the plans were changed was because although I became part of the project just a few weeks ago, when Kelly and Udi were already in Brazil, there was some footage in Spanish from Mexico they were finding hard to comprehend in detail. Kelly was writing the post The autonomy of Poo and asked me if I could help her understand the whole process of building the poo box. I found that César Añorve’s explanation was so informative and humorous at the same time, that it deserved to be shared in its own post:

César explaining the first steps of the process. Photo by Udi

Although César calls it a poo box, it is also more formally referred to as an ecological dry toilet, precisely because it does not require the use of water and, in that way, it does not pollute rivers, seas and oceans. All this can be better understood by reading about how it is built and how it works:

Elements: (“The simplest elements in the world”)

For the poo:

  • 1 plastic bucket
  • Dry dirt
  • “dry leaves that we might find near our house”
  • “charcoal powder, which you can get for a very low price; it is the leftovers of the coalyards, here we call it cisco.” Or, one can put olotes (the corn’s cobs) in the fire and wait until they are carbonized. In this way, you can make your own coal.
  • Optional ingredients: marble or steel powder, which are sold in construction shops, very fine sand, lime.

As César said: “It is like life: the more diversity the better.”

For the pee:

  • Plastic recipient, “so that the pee does not stink while being stored”
  • Hose
  • Funnel
  • Bowl.

To place on top:

Wooden box with 3 holes:

  • One big hole on one of the sides of the box, through which the bucket is introduced and taken out.
  • A small hole on the opposite side, not too big, but big enough for a hand and an arm to be introduced through it.
  • Hole on the top of the box, where one will sit.

Sticking the sides of the wooden box together. Photo by Udi.

How to build it:

1)      Take the bucket and throw in the dirt, the dried leaves and the coal. Add the other elements if you were able to get them.

2)      Add a small piece of flat wood inside the box, under the smallest side hole.

3)      Place the box over the bucket.

4)      Put the bowl on the small piece of wood you have added under the small side hole.

¡So simple!

There is a slightly more complex option in which instead of the wooden box, one can build a whole chamber with a door through which the bucket can be placed and removed. In this model, the pee bowl or container is already connected to the recipient through the hose, so one does not need to empty the bowl every time the toilet is used.

All the elements of the dry toilet put together. In this case, using the chamber instead of the wooden box. Picture taken from César’s book “The ABC’s of Ecological Sanitation”

Proper use of the dry toilet:

1)      When sitting on the toilet make sure that the feces fall into the bucket and the urine into the bowl or separator. This separation is the key to the toilet’s proper functioning: it avoids humidity and bad odors. “This separation of pee and poo is pretty easy for men. Women can manipulate the bowl”, introducing their hand through the smaller hole. “Women’s perspective has been taken into account for every design of the poo-box.” It has been tried before by many of César’s friends who were then consulted about the position in which they preferred the bowl to be (higher, lower, the distance it should keep from the bucket, etc)

2)      If you have built the more complex version of the dry toilet, the urine will go directly to the recipient though the hose. If you have the simpler version with the bowl, before throwing it into the recipient using the hose and the funnel, you can take a small sip, the size of a full spoon. Urine is very good for the health.

3)      After every use of the toilet, cover the excrement in the bucket with a mixture of fine dry soil and lime and/or dry leaves. This dries the surface, avoiding bad odors and the proliferation of insects.

4)      After doing this, always cover the bucket.

What happens with the poo and the pee once they have left our bodies?

Urine as fertilizer

Urine contains a high concentration of nutrients such as nitrogen, phosphorus and potassium. Also, it contains urea, which after a time turns into ammonia, the fertilizer most used in agriculture. Therefore, the urine stored in the container can be mixed with water and used as a fertilizer for garden plants. The proportion should be one part urine, ten parts water. By doing this, a family of six people can produce more than five thousand liters of fertilizer every year. Options for the use of the urine:

  • Apply directly to the base of the plants.
  • Spray it on plants and fruit trees using a hose.
  • Add to the compost.

Excrement as compost

When you see that the bucket is full:

1)      Remove it from the box or chamber and replace it with another bucket. The bucket that has been removed needs to sit for enough time until it dries completely.

2)      After this period, open it. You will be able to see that the dried leaves are covered with a white thing. This will be because of the transformation carried out by the microorganisms. The excrement has dried out and has been converted into an “odorless granular dust”.

3)      You can use this rich compost to fertilize a garden or fruit trees just by throwing it to the earth, or you can take a big flower pot and throw the content of the bucket into the pot. (By doing this, the same family of six can produce 500 litres of organic compost each year.)

The result: the odorless compost. Photo by Udi

If you chose the latter,

1)      Add food leftovers and earthworms to the compost in the pot

2)      Add a little bit more dried leaves on top of everything.

3)      Compact the mixture inside the pot.

4)      Repeat the whole procedure as many times as you need until you have filled the whole pot. You will be able to appreciate how the content of the pot reduces constantly. These are the microorganisms doing their work.

5)      After a few days, start observing the content of the pot attentively: you will be able to appreciate how a plant starts growing. “In my case, I got and aguacate and a chilli”.


The process that has taken place here is amazing. Our waste, which we thought dead, which we thought of as that, as waste, has been literally transformed into a living being, into a plant. When I heard Cesar’s explanation for the first time I could not believe this had happened. This got me thinking, and although the post has been written in a slightly “funny” tone, truth is I felt this knowledge had to be shared, since the idea of the dry toilet is so innovative and interesting to me on so many levels:

In the first place, there is the most obvious question of pollution. By using a dry toilet, we are not polluting the water we drink. This is a big issue in many places in the world: many diseases are generated by drinking water which has been polluted with excrements. “When we avoid using water to transport excrement, this is a radical action which can contribute to returning the sacred character that water may have had before the era of sewage systems”. At the same time, from a more practical point of view, there is the question of the re-using. Our excrements and urine are not waste but are re-used. This represents and economic advantage, because we save on fertilizers and are able to produce more vegetables and fruit. What is being created here, homemade, is a natural storage of nutrients.

This last point is also very interesting. By using a dry toilet we are making ourselves responsible for our own waste and, at the same time, generating our own compost and fertilizers. We are being self-sufficient. This relates to the idea of autonomy Udi and Kelly developed in one of their posts (Learning Autonomy). Before reading it, I had never thought of autonomy in this way, a collective autonomy through which a community is capable of generating its own resources and becoming self-sufficient. At the same time, the process of autonomy also means to become conscious of our own dependencies and interdependencies and reflect and recognize them. As Kelly points out, only by considering and exploring other options we will be able to perceive and act on our dependencies. The dry toilet is one of these options. Before being introduced to it, I had not really considered the possibility of other options for my poo and pee. I had not deeply reflected on what happened to them after they left my body and I had not thought about the traditional toilet system as one of my dependencies.

Finally, in relation to recognizing our interdependencies, the toilet made me reflect not only on how we depend on the State´s sewage system but also of other interdependencies: the interdependencies within nature. The dry toilet shows very clearly and explicitly the idea of the cycle of life: the food we eat, is transformed into energy and feces and urine, which then serve as fertilizer to grow more food. It is an example of the transformations that take place in nature. And for these cycles and transformations to take place, each being needs of other beings: the soil needs the excrements to become compost, the seed needs this compost to become a plant. And also, as César explained, the earth in the pot needs the plant to continue its transformation process. Therefore, what are we, humans, if not just a part in this cycle of life? And as such, we should be taking something from the world but also giving something to it, just as with the dry toilette, through which the food we have taken is given back to the earth as compost.

Picture from César’s book “The ABC’s of Ecological Sanitation”


I know that probably most of the people that read this post will not actually build a dry toilet in their homes (It would be great, however, if you do it and you can find more information about it at the bottom of the page). Regardless, I wanted to share my reflections about what the idea of the dry toilet generated for me. It is only when we know that other options are possible, that other ways of understanding something exists, that we will be able to reconsider and re-think about our own ways.

From César’s book

* All quotes are either what César said during his class in Unitierra or direct quotes from his book The ABC’s of Ecological Sanitation.(2004, Centre for Innovation in Alternative Technology A.C., Mexico)

Cover of César’s book

**For more information write to César:

Centro de Innovación en Tecnología Alternativa A.C.

Av. San Diego No. 501,

Col. Vista Hermosa

CP 62290 Cuernavaca, Morelos, México




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The Autonomy of Poo…

The Autonomy of Poo…

Posted by on Jan 10, 2013 in all posts, Mexico, Universidad de la Tierra | 0 comments

Cezar Añorve leads a ‘cacaravan’ workshop on dry toilets at Unitierra, still from footage by Udi

Conversations about autonomy centered on some surprising topics during our stay at Unitierra.  Talks about (and practices of) the autonomy and self-sufficiency of the production of food, we were, in many ways, expecting.  What we were not expecting was that there would be so much talk about shit.  And… there was a lot of talk about shit while we were at Unitierra, as related to autonomy.  As Gustavo explained during the interview we did with him, ‘we care about shit… as much as we care about food.’  For, you cannot talk about the autonomy of food without understanding the importance of the autonomy of poo (waste).  And with this mind, you can also not talk about the autonomy of food and poo without also talking about the autonomy of water.  They are all clearly related.  In fact, learning about autonomy forces me to learn more about how these connect together, rather than learning more about each ‘sector’ separately.

Waste from humans and other animals, as we all know, is described in all sorts of ways – humorous and informal, technical and scientific… Although I heard ‘shit’ as most often related to humans (whilst at Unitierra), I’ll instead use ‘poo’ for most of this post … I remember in Bangladesh when we were looking into the 100% Sanitation Act national policy, that engaging in the act of releasing waste (poo-ing) was always referred to as ‘when the nature calls’.  Regardless of word use, the topic is immensely important – it causes huge numbers of unnecessary illnesses and premature deaths (especially through contamination of waterways) to humans, animals and plants in every country in the world.  And, the quest for the top multi-national corporations (Suez, Veolia Environnment (both from France) Thames Water (out of the UK) to control and privatize all water commons for their own self-profit making interests is becoming increasingly problematic and volatile in many regions in the world.  We recently learned more about water privatization in the wonderful documentary, Fl0w: For the Love of Water (can be viewed in full here).

The topic of poo came up in all sorts of ways during our stay in Oaxaca – as a resource, as a contaminant, as potential sustenance (into composted fertilizer). There was talk about poo during the workshop within which we helped to construct a mud and (burro) poo stove with Unitierra in a community (primarily of indigenous migrants from across Mexico) outside of Oaxaca city. Stove-building workshops have been occurring through Unitierra very often over the past several years – in over 25 different communities in and around Oaxaca at the request of community members themselves. The women from Unitierra who were helping to run the workshop, were initially learners themselves, having asked previously to have a mud stove in their own family homes. Having a stove such as this helps to increase the self-sufficiency of families to rely less on gas for stoves inside of their own kitchens. The stoves are heated through wood or dried… shit – from burros, cows and/or horses. Unitierra does not pay for any of the materials. The families are expected to pay for the bricks, a pipe and supply enough mud/poo. They also need to fix a space big enough to build the stove.

When we arrived with Adriana and from Unitierra at a family’s house in a suburb of Oaxaca to learn about, and help build a mud stove, I found myself staring at a large pile of soft dirt. Yet, this was only 25% dirt. The other 75% was burro poo.

Preparation material – mud and burro poo – for building a stove, photo by Udi

I was a bit (unsurprisingly) resistant to put my hands into the mound of mostly-burro-poo. I guess I wasn’t entirely prepared to get my hands that dirty…

Bricks as the foundation for the stove, photo by Udi

The mixture however, smelled of fresh Earth and I soon found myself completely lost in using my hands to mold a thick layer of Earth/poo around bricks that would be used to fry tortillas, boil frijoles and heat up tamales.

Moulding the stove, photo by Udi

The layout of the stove is rather brilliant and locks in heat extremely well.  It took us a couple of hours of talking, laughing and molding to finish the stove.

Finished stove, outside of Oaxaca city, photo by Udi

Finished mud/poo stove, photo by Udi

Aside from the burro poo and mud stove, there was talk about poo when we learned how to construct a dry compostable toilet during a workshop from Cesar Añorve , a brilliant architect from Cuernavaca who has been working for the last 40 years to teach about and implement such vestibules in people’s homes, offices and public spaces.  Cesar started an organization, El Centro de Innovación en Tecnología Alternativa (The Center for Innovation in Alternative Technologies) through which he promotes knowledge and technical skills on dry toilets, amongst other innovations.  During the compostable toilet workshop at Unitierra, I was urged to critically consider how the State controls even my own digestive system because of our reliance on the State for the disposal of our own… poo.  To be autonomous from the State, I needed to consider how to disconnect my stomach from it.

There was talk about poo when we were urged to consider how we pollute our own water commons – by mindlessly flushing our poo into it – day after day after day after day… Should water be the receptacle of our own waste? Is not water sacred to all life on Earth? Why is it that we so carelessly pollute it? Over half of our water use is for the taking away of our own waste. We rely and depend on a sophisticated system of piping and sewage treatment systems, which are often not up to standard or even used at all, varying from country to country and place to place around the world. The logic of the ‘flow’ of public water systems makes little sense when we think about the entire system of it. ‘When the nature calls’, we poo into freshwater, a finite resource, flush it away into our waterways – the flush polluting these waterways directly or separating it into massive sewage treatment plants (which uses huge amount of energy, more water and chemicals which further poison the waterways). Cesar reckons that the water we flush down the toilet over the course of one year is what we drink in 40 years.

Cacaravan workshop with Cesar Añorve, Unitierra, Oaxaca, photo by Kelly

I must say that I had not thought much about what happens to my poo or anyone else’s poo for that matter, for …. well…. about three years. And that was when I first encountered (quite unexpectedly) the wisdom of the disposal of our poo in dry compostable toilets explained in a brilliant undergraduate dissertation by Jessica Smith at Wesleyan University in the USA.

At that time, I was finishing a comprehensive literature review (as a Working Paper publication) for a 2-year research project, Whose Public Action? at the University of Birmingham which had looked into the dynamics of relationships between civil society organizations (also called non-profit, non-governmental, etc.) and the State (national and district level) to provide ‘basic services’ such as sanitation, water, health and education. This research project was one of over 50 projects funded by the UK Economic and Social Research Council (ESRC) on the overarching topic of Non-Governmental Public Action.  For this research project I had worked on, we had particular case studies in India, Pakistan and Bangladesh.  Aside from fascinating fieldwork I participated in (primarily in the sanitation cases in Bangladesh and India – I will write more about this project in future posts), I spent several months poring over hundreds of articles and books to produce a comprehensive literature review on the ways in which relationships (or ‘partnerships’ as the international development jargon prefers to call them) between civil society and government/State organizations are understood, theorized and described.  Aside from a couple of anthropologically-focused studies which got into some of the nuances and power games that are inherent in all relationships (let alone relationships between such different types of organizations), the literature was incredibly dry and, in my opinion, ridiculously simplistic – most-often reducing relationships to adjectives such as ‘competitive’ and ‘co-operative.’ To say I was bored and uninspired at that point is an understatement. That is, until I came across a dissertation entitled: “The Separation between Shit and State” Water Sovereignty and the New Commons in Cuernevaca, Mexico by Jessica Smith.

Much of the dissertation is a personal learning account of Jessica’s travels with the International Honors Program (IHP) which was a year-long learning experience to different cities and places around the world, as an option for undergraduate university students during their studies. Gustavo helped found and was deeply involved in the IHP for many years. Jessica wrote about her visit to Unitierra and the fortuitous coincidence of meeting Cesar Añorve – and learning about not only how to build a dry compostable toilet, but learning many intricacies about what is wrong with international development.  In particular, her research explores ‘the commons’ and ‘community’ – ‘not as tragedies or casualties of the modern era, but as something men and women the world over are working to regenerate’ (p. 4).

Through the promotion of the implementation of the dry compostable toilet, Jessica tells us that Cesar is providing the tools for water sovereignty. Similar to food sovereignty, water sovereignty is about being responsible of your own water management, through a local and community-based ‘commons’ autonomy that is centred around reciprocity. Sovereignty in all forms – water, waste and food – opposes the strong tendency in international development that seeks market-based solutions in larger non-local, global-economic systems. This is because in essence, although there are calls for ‘self’ and ‘community reliance’ development is much more about providing – resources, materials and knowledge, which inevitably brings about relationships of dependency, and ultimately the erosion of culture – ‘culture-cide’.

Back in Unitierra, when Gustavo was telling us about education and its capacity for destruction – for ‘culture-cide’, I was considering the need for autonomous forms of learning and how and where this can and does occur. I was not putting together these other areas – particularly water and waste. These new forms of learning, of re-learning, for me that continues to occur through this journey, comes in waves – often quite subtle. Much of these ‘learnings’ seem to be about connections and the realization of how often I separate knowledge into different categories automatically, intentionally or not.

Photo taken by Udi – dry compostable eco-toilet (using Cesar Añorve´s technology) on the way to the roof garden at Unitierra

When the conversation with Gustavo shifted to our plans during our stay there was a twinkle in his eyes when he mentioned a special workshop that was going to occur on Saturday with Cesar Añorve. I immediately knew who he was referring to and what the topic of the workshop would be about.  Cesar has been coming to Unitierra once or twice per year so I felt it was extremely serendipitous that during our stay I would meet the man and learn his knowledge that I found so unexpectedly captivating through Jessica’s dissertation!

Cesar’s commitment to promoting autonomy and environmental concerns through an activity most of us rarely think about, unless something goes wrong, is admirable. He has spent years on countless projects in different countries and with no concern for personal profit on dry toilets or on systems that reuse water. These range from the simple dry toilets we could all build in our own houses with very few materials to more complex systems in schools and whole buildings involving more elaborate water engineering. What was wonderful to see, and what was contagious about his work, was both the simplicity of the systems he had designed as well as his passion for taking forward his message of the importance of, as he put it, ‘not shitting on water’.

Sketch by Cesar Añorve, from slide presentation at Unitierra dry toilet workshop, photo by Udi

To this end he also toured various places, giving workshops to teach others how to build these structures – to realize that the technology is simple, straightforward and does not pollute people’s houses. All this is part of what he calls his cacaravan the nomadic journey of, as he himself puts it, a cacalogist.  His journeys take him near (across Mexico) and far (in China such as this photo shows).

Photo used in slide presentation, dry toilet workshop with Cesar Añorve, photo by Udi

Cesar uses his humorous play on words in his sketches as well, which helps to bring about a lightness to the seriousness in which he conveys his political messages alongside his technology (we will soon be publishing a separate post with more information on Cesar´s technology – although this is a direct link).

The significant connection with Gustavo and Unitierra is also that of autonomy and a long friendship which also stretches back to Ivan Illich. Towards the end of his life one of the last things Illich (a former priest and long-time student of theology) said to Cesar, which he movingly related in the workshop, was something to the extent that one knows God not through the mind or heart but through the stomach. This seems to have a resonating depth not only through the conversion of poo into pollution (or the reverse process back into compost which Cesar promotes) but also in terms of the centrality of food, of the milpa and maize that we have been learning so much about.

The connection Cesar had to the rivers and waterways and his desire to make them clean once again so that the following generations might be able to enjoy and swim and play in these as he did as a child was palpable and inspiring. What was also exciting to see in his work was how, over such a seemingly simple and misleadingly inconsequential activity, so much could be developed in terms of innovations of the toilet structures and addition of simple substances to speed up the transformation of poo into compost and new life.  I learned much about the links between food and water sovereingty that day – and the inseparable link with the management of our own waste.

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