Solar CITIES' Decentralized Biodigester Project for Hunter Gatherer and Nomadic/Semi-Nomadic Communities
By T.H.Culhane, Ph.D.
"Guardians of Biodiversity: The Hadza’s Journey with Microbial and Ecological Innovation"
For some 40,000 years the Hadza people have been the stewards and co-creators of unique ecologies in northeast Tanzania. Through their landscape interactions, food and fiber harvesting and dietary practices they have maintained and enhanced healthy thriving rainforests, decidous forests, shrub ecosystems and savannah and other flora and fauna ecosystems throughout the region and maintained healthy thriving skin and gut microflora and fauna on and within their own bodies. They have become famous the world over for having the most diverse and robust microbiome on the planet – see the NPR feature “Is the secret to a healthier microbiome hidden in the Hadza diet?” and “Hunter-gatherer lifestyle fosters thriving gut microbiome in Nature for starters (https://www.npr.org/sections/goatsandsoda/2017/08/24/545631521/is-the-secret-to-a-healthier-microbiome-hidden-in-the-hadza-diet and https://www.nature.com/articles/d41586-023-02065-y)
In the study reported by Nature the authors state, “The Hadza had an average of 730 species of gut microbe per person. The average Californian gut microbiome contained just 277 species...The team also found species in the Hadza microbiomes that were not present in the Californian samples, such as the corkscrew-shaped bacterium Treponema succinifaciens. Only some of the Nepali microbiomes contained this microbe, suggesting that the bacterium is dying out as societies become more industrialized.”
Thus the world is coming to realize that the Hadza are not only guardians of imperiled biodiversity on a macro scale, but on the micro-level as well.
An article in “The Conversation” by Jeff Leach, Visiting Research Fellow, King's College London, gave some insight into how the interactions between Hadza people and wildlife result in this extended ecology. He wrote,
“Living and working among the Hadza makes me think of the intimate relationship humans have probably evolved with diverse groups of microbes. With each animal killed, microbes are given the opportunity to move from one species to the next. With each berry that is plucked from a bush or tuber dug from beneath the microbial-rich ground, each and every act of foraging keeps the Hadza connected to an extensive regional (microbial) species pool.
It is their persistent exposure to this rich pool of microorganisms that has endowed the Hadza with an extraordinary diversity of microbes; much greater than we see among people in the so-called developed world.”
(https://theconversation.com/east-african-hunter-gatherer-research-suggests-the-human-microbiome-is-an-ecological-disaster-zone-73668)
The article contains a picture that Dr. Leach took of a “Hadza hunter cleaning blood from his hands with the microbial-rich stomach contents of the same animal” and many studies have commented that the Hadza maintain their species-rich microbiome not only through what they eat but through this practice of smearing their bodies with the rich fluids found in the gastrointestinal system of the animals they prey on.
A popular article in New York magazine’s nutrition section called “The Scientists Who Want to Fix America’s Intestines Started With Their Own” corroborated this, stating,
“When scientists study the microbiota of a traditional hunter-gatherer society like that of the Hadza in Tanzania, who eat ten times the fiber of the average American, they find far greater microbial diversity. (The Hadza also slaughter animals with their hands and clean off the blood using the animal’s digesta — a boost to microbial exposure.) The Hadza have avoided Western afflictions such as obesity and diabetes, which the Sonnenburgs see as evidence that their guts are in better shape than our own.”
(https://www.thecut.com/2015/04/sonnenburg-family-stomach-bacteria.html)
Meanwhile, an article in Yale University’s eHRAF World Cultures website on the Hadza tells us, “Girls sometimes decorate themselves by smearing animal fat (also used as lotion) on their faces as an adhesive for colorful flower petals”; this would be another source of microbial rich unctions that improve skin health.
(https://ehrafworldcultures.yale.edu/cultures/fn11/summary)
The conclusion we can draw is that of all the people’s in the world, the Hadza have one of the most intimate relationships with the natural nano-technology of the invisible but potent microbial world.
Their lived understanding of the power of symbiosis with the unseen realms of biology and their deep reverence for biodiversity and deep ecology make them great potential partners for participation in and leadership in the biomimicry (r)evolution that is taking place in applied sustainability discourse aimed at helping humanity meet our 17 UN Sustainability Goals. From our perspective at the University of South Florida, their practical and historical experience with life-tested Nexus Thinking and traditional WEFe (Water Food Energy Ecology) Nexus Technologies make collaboration with our Solar CITIES/Rosebud Continuum Eco-Science Center/Patel College of Global Sustainability research ideal.
The possibilities become especially powerful when considering how applied biodigester research could complement the Hadza lifestyle and cosmology and offer a new model for waste management, food security and clean energy provision.
"Empowering the Hadza with Biodiversity: Harnessing the Microbiome for Sustainable Energy and Ecological Stewardship"
The first thing to note about collaboration with the Hadza and their allies in applied biodigester implementation is the empowerment aspect—small scale distributed biogas systems would augment the autonomy of the Hadza through this simple biodiversity enhancing microbiome technology.
We propose to collaborate with the Hadza to implement small-scale mobile biodigesters using designs that affirm the holistic, ecological stewardship ethic that reflects the Hadza's traditional wisdom. With biodigester’s reconceived to fit into nomadic or semi-nomadic “hunter-gatherer” lifestyles we suggest an innovative use of an ancient rural technology, well known in China and India as a traditional farm based solution for animal herders that eliminates the “wastes” their livestock produce, creating reliable cooking fuel and liquid compost, and more recently has been used to transform urban food waste streams into clean cogeneration fuel and saleable nutrient-rich healthy fertilizer. Our goal in this project collaboration is to explore community sized biodigesters as a bridge between tradition and technology for non-sedentary populations.
Integrating biodigester technology into hunter gatherer communities might be considered a “first” in human history, but on the other hand it is quite conceivable that our ancestors, well aware of the flammable gasses produced by the intestines of animals and by swamps and ponds, already integrated some aspect of biodigestion into their lifestyles in some areas. This author is aware, through conversations with Egyptian Fellahin (peasants) and trash recyclers in the Philippines, that most people in their communities knew about biogas systems and used them until discouraged or forbidden by State Power Holders. An Egyptian taxi driver I spoke to who had migrated to the city in search of work after government and corporate land grabs took away his farm said that “we always used to dig a pit in the ground, throw our animal dung and food wastes in, cover it with mud and straw, stick a bamboo pipe into it and use the gas for cooking and lights”. Evidence of rural biogas use goes back at least 3,000 years, so this is nothing new to the human experience. What might be novel is the application to our nomadic heritage which the Hadza have preserved.
Mobility is a key aspect of the Hadza's resilience and ecological stewardship. Like the Bedouins or other nomadic groups I’ve met with in the Negev, in Palestine, in Jordan, Syria and Egypt, they rely on movement to prevent over-extraction of resources and to allow ecosystems to regenerate. However, strategic placements of small-scale, mobile biodigesters along their well-trodden paths could harmonize with this lifestyle. They would not be forced to settle around the technology, but instead, see it as a tool that integrates into their broader patterns of movement. These digesters could provide renewable energy and nutrient-rich fertilizer to enhance the biodiversity along their trails, mimicking the natural enrichment practices of Amazonian Indigenous peoples, as described by my Ph.D. advisor Dr. Susanna Hecht (author of “Fate of the Forest”). Dr. Hecht lectures about her time living with the forest peoples of Boliva who were considered “hunter gatherers” but who actually strongly influenced what grew along their trails, intentionally providing habitat, shelter, medicines and foods for people and wildlife so that hunting and gathering was more like path harvesting than “searching for a meal”.
Observing and speaking with Bedouins in the Wadi Rum desert valley in Jordan two summers ago, it also became clear to me that the desert today was expanding in many ways because the people were no longer moving with their herds of camels and sheep and goats which traditionally deposited fertility and water along the trails. Migratory animal movement and intentional movement along trading routes made these paths in the desert bloom rather than degrade. The introduction of motorized vehicles and government insistence on “settlements” and fencing and restricted grazing plots is most often the cause of desertification. In the case of the bedouins of Wadi Rum we can now see that the most fertile areas are at wells, oases and tourist encampments and also between them where eco-tourism guides offer camel tours and the animals redistribute the well water and nutrients they consumed at the oases across the desert paths.
"Nomadic Wisdom Meets Microbial Innovation: Biogas Solutions for the Hadza's Sustainable Future"
Through the blending of nomadic traditions with cutting-edge microbial technology, we suggest that biodigester solutions could respect and build on the Hadza's existing ecological knowledge.
Framing the idea of using biodigesters in nomadic or semi-nomadic cultures like the Hadza requires a balance between respecting their traditional movement patterns and offering a tool that can enhance sustainability without forcing sedentism. One way to position this would be to emphasize that biodigesters can be conceived as "stationary wildlife companions" along their migratory paths. This use of biodigesters, seeing them as “fire breathing, nutrient peeing animal allies” would not interrupt their ecological wisdom but instead support it.
The biodigesters would act as environmental stewardship technologies in much the same way that the Hadza use hunting techniques and practices that maintain balance within their ecosystems. Rather than extracting from the land and then moving on, the Hadza could use digesters, situated at campsites along their paths of sustenance, to leave behind small contributions of fertility and energy and targeted plant cover, which could attract game animals or enhance the natural growth of medicinal plants, berries, and tubers along their travel routes. This supports their way of life while adding a new layer of sustainability that does not compromise their mobility.
By distributing biodigesters as "waypoints," the Hadza would also have cooking fuel when they stop to rest or set up temporary camps. This reduces the need for cutting wood or relying on other energy sources that could degrade their environment. Additionally, we could compare this setup to modern campsite infrastructure around the world, where people carrying tents and backpacks have access each night or during their hikes to basic utilities without being tied down.
This way, we preserve Hadza autonomy and traditions while introducing biodigesters as part of their ecological system rather than something foreign and sedentary. By presenting it as a natural extension of their existing practices, we are likely to find a more receptive audience to this innovative application of biogas technology.
Design of the “semi-nomadic dragon digesters”
To make this work, 3 biodigester designs seem most appropriate and all could be utilized in various locations, depending on the preference of the Hadza.
1. One would be the easily deployable “Solar CITIES IBC tank digester” design explained in our book here:
https://solarcities.solutions/resources/
https://www.echocommunity.org/en/resources/9b8a924f-f3a9-4104-83da-fc420a52cc19
https://www.youtube.com/watch?v=tdA4BqSEESU&t=145s
Since 1m3 IBC shipping containers are found in literally every corner of the world, being an industry standard, we created this system with the Zabaleen trash recycling community in Cairo back in 2009 and have built them with National Geographic, US State Department and University and NGO funding all over the world, from Alaska to Botswana, including several in Tanzania. When empty they are light enough to be rolled into place by an individual, carried up steps or rocks and basically deployed anywhere with ease, regardless of the surface. When filled with water they weigh a ton and resist damage and displacement very well.
Solar CITIES style IBC digesters are an open source design and can be constructed using local materials and each produce about 2 hours of cooking fuel on a hot day and 20 liters of liquid compost from a single bucket of organic feedstock (foodwaste/toilet waste, animal manures, inedible fruits and berries, crushed insects, worms and larvae etc.).
Our systems can be put on pallets or skids or on wheels to be more mobile, or can be easily drained, moved and refilled as needed.
2. Another digester design is the (B) Energy design developed in Ethiopia by the communities with German small business development champion Katrin Puetz, originator of the mobile “biogas backpack” that enables families to bring cooking fuel home from distributed networks of farm or home biodigesters.
See https://empowering-people-network.siemens-stiftung.org/organizations/benergy/ and https://be-nrg.com/buy-our-products/
3. A third option is Flexi-Biogas, run by our friend and colleague Dominic Wanjahia Kuhumbu in Nairobi, Kenya: https://biogas.co.ke/flexi-domestic-systems/
All of these options can be deployed or built locally and in a radically decentralized fashion and drained and moved if/when necessary. They do not have to be considered “hardscape” fixed infrastructure and therefore are easier to use without getting into issues about permanence.
We conceive of digesters being located in rest areas and campsites along trails and within home camp circles that would benefit the Hadza and be identified by them.
We could incorporate free and open source QGIS mapping software teaching into the school being built and include this kind of participatory community design planning into the video and digital storytelling being offered.
A good way to get started is to see who in the Hadza community and who working with the school you are helping build is interested in working on the QGIS mapping/planning and subsequent conversations.
Once we know the locations of the most used trails and willing participants of campsites/villages/dwelling spaces we can construct viable maps and animations/simulations for community discussion.
This is as easy as right clicking on a maps.google.com map and giving us the decimal degree coordinates, like this:
Then we plot these locations in QGIS as vector data point layers and put in symbols for the proposed biodigesters.
From there we can generate animated topographical maps that can be used in video presentations and community meetings to pre-visualize the project.
Animation:
We can export all of the data in the open source modeling and visualization program “Blender 3D” with Blender GIS installed and do detailed fly throughs/walk throughs of the landscape with proposed modifications.
In Blender we can put 3D models of the biodigesters and solar panels and any other landscape possibilities we imagine:
This ability to previsualize landscape interventions allows for democratization of the development process, allowing all stakeholders, regardless of formal education or training, to participate. The simulation can be done in a VR application like Spatial.io and Hadza community members can be invited to visit in augmented reality to get the “walkabout” experience before committing to any actual implementations in the real world.
A new model of decentralization for sustainability
Much sustainability thought over the past half century has focused on “decentralization” and “distributed energy”, on “locavore” habits and on bioregionalism. Nonetheless, our collective failure to implement these strategies for the collective good may stem from our anything but decentralized lifestyle, and begs the question, “what might happen if we took a step “back” and designed our infrastructure for the already decentralized lifestyles of the peoples whose way of living has endured the longest? What if we helped deploy “sustainability” technologies with those who have proven their lifestyle is sustainable?
Combining biodigesters with the nomadic lifestyle of hunter-gatherer communities like the Hadza would complement efforts we’ve made with Native American groups and with the Masai, but would go further because, although Solar CITIES has worked with the Lakota Sioux and the Muscogee and the Masai, we’ve always worked in schools and ecovillages that have already surrendered to the constraints of sedentism, despite the rich nomadic traditions of these proud peoples . By placing biodigester sustainability hubs strategically along
ould be introducing sustainable waste management, energy production, and agricultural opportunities without forcing or even “nudging” these groups further into a sedentary way of life.
The idea of "park-like" biodigester hubs is a way of using technology to act as key ecological nodes in the landscape. By converting organic waste into biogas and nutrient-rich slurry in decentralized locations, the biodigesters can provide fertigation (fertilizer AND irrigation) to support plant growth around the hubs. This creates localized, enriched ecosystems that both the community and wildlife can benefit from. These hubs could serve as rest points, where people can cook using biogas instead of relying on firewood, thus preserving forests and mitigating the environmental impact of deforestation.
The portability of biodigester technology could also be an important factor. While the Hadza might not want large permanent structures, modular or even mobile biodigester units could allow for temporary energy and fertilizer production at these locations. This way, the technology complements their nomadic movements instead of imposing static development.
What would be interesting is to further explore how to design biodigesters that are lightweight and portable, or how to integrate a decentralized energy network that doesn't tether the community to a single place. We propose a design charrette that reveals how nomadic groups could engage with the biodigester hubs throughout different seasons,and discusses what kind of additional infrastructure (like water storage) might be needed to ensure sustainability in dry periods.
My experience in the Yucatan with the Maya gave me insights into integrating traditional knowledge with sustainable technologies. The Maya communities have been managing rainwater catchment and irrigation for centuries, often in a way that complements the natural environment. A parallel can be drawn with the Hadza and other nomadic groups when it comes to balancing modern sustainable technologies like biodigesters with their traditional way of life.
In both cases, water management is key. Just like the rainwater catchment systems in the Yucatan, biodigester hubs for nomadic groups would need to take local water availability into account. Perhaps a decentralized rainwater catchment system could be integrated with the biodigester hubs to store and provide water for both human use and fertigation in areas where they establish temporary camps. This could help the communities during dry seasons or in arid regions.
Our proposal in the Yucatan was to combine rainwater catchment with biodigester systems for fertigation. Rainwater alone is essentially "distilled" and lacks the nutrients plants need for growth. By running the rainwater through a biodigester first, we are not only conserving water but also enriching it with nutrients from organic waste. This biologically active system can turn that nutrient-poor rainwater into a nutrient-rich slurry, which is much more beneficial for plants.
The biodigester essentially acts as a natural processing unit, turning organic waste into a potent fertilizer and adding value to the rainwater by making it nutrient-dense. It would also improve soil health and support long-term plant growth, aiding in soil creation where it may be thin or degraded.
Our model, where each biodigester hub has its own rainwater catchment system feeding into the digester, would create a self-sustaining cycle, efficiently managing both water and waste while promoting plant growth. This could also be a big advantage in areas with seasonal water availability, where stored rainwater can be gradually released through the fertigation system, supporting both the ecosystem and human needs without depleting the environment.
Note that we are not talking about introducing “agriculture” here, but are rather adapting permaculture principles to a nomadic or semi-nomadic way of benefiting the landscape. Distributed biodigesters become simply other “animals” in the landscape providing the usual ecosystem services that have sustained the Hadza for tens of thousands of years. Animals consume vegetation and/or other animals and then add nutrients and energy to their trails, creating a self-sustaining ecosystem.
I personally witnessed this.
When I was in Egypt in 2003 I went to the Basa Issa Eco-Village in the Sinai where there was a biogas conference. They had a big concrete Chinese biodigester underground next to the solar village building and the experts from Egypt and China, India, Germany and the UK gave talks on biogas. It seemed like the perfect solution. But when I went to talk to the Bedouins in the kitchen about biogas, people who have also been nomadic for tens of thousands of years, they laughed when I said, “that must be the biogas flame you're cooking on.” They said, no, it's from Butagas bottles. We don't use the digester because we think it's ridiculous. These foreigners come in here and tell us how wonderful biogas is, but then to use it we have to take all our animals into one location and build a corral for them, keep the animals concentrated, let them poop and then shovel the poop into the digester. To make it worse, we then have to carry out the slurry on a donkey cart to try to fertilize our fields.” They shook their heads at what they felt was the stupidity of sedentary peoples. “Cows have legs, animals have legs, they can walk and poop and pee and they can fertilize the fields by themselves and eat by themselves. This has always been our way. Only idiots would make the effort to corral them and then have to go out into the fields ourselves to bring food in for them and then have to shovel their poop in all just to get some gas. Fossil fuels are cheap – we can get these bottles of butagas for almost nothing because it's subsidized by the government anyway. And then we don't have to carry the fertilizer back out to the fields.”
Because of my conversations with Bedouins in the Negev desert, in Syria and in the Sinai, I was against the exogenous promotion of biogas from 2003 when I went to that conference at Basaissa until 2009 when I went to India and experienced urban biogas with Arti India and talked with families who used abundant and otherwise problematic food wastes to produce their fuel and fertilizer. That radically decentralized way of using biodigesters sold me on it and made a lifelong lifetesting champion of the technology all over the world.
Now we are figuring out a way to get biogas back out into countryside regions, not just to rural people who have domestic livestock, but to hunter-gatherers like the Hadza in Tanzania. But we must ask the question, if you don’t have a lot of food waste, as people do in the city, and you don’t corral animals, where is the feedstock realistically going to come from?
Biodigesters re-conceived!
Since a biodigester doesn’t have legs, it can’t “forage on its own”. So in this sense, while we call our biodgesters, “domestic dragons”, unless we put in the money and time to place them on trailers with wheels and invest in tractors or pickup trucks and their fueling to move those trailers, they are going to be static features in the landscape. Does this defeat the purpose?
Absolutely not! In the case of the hunter-gatherer community application we can re-conceive the biodigester as a “domesticated termite mound”. In the case of “P.E.T.E.S. Dragon” at the Rosebud Continuum Eco-Science Center in Florida, we embraced the domestic dragon narrative because we are on a sedentary homestead. We painted and sculpted the digester (even using “trashcrete” to make use of shredded plastic and crushed glass waste as the sculptural material) to fit that storyline so that when school kids visit they immediately grasp the concept.
But in Tanzania it could best be artistically transformed into a termite mound – a ubiquitous feature in the landscape.
This could be a Puxin digester of 10m3:
Imagine biodigesters that looked like this!
This could be a Solar CITIES IBC tank digester!
The social insect analogy for biodigestion: Moving beyond “Domestic Dragons” to “Domesticated Insect Mounds”
Termites (Isoptera) and other social insects (Hymenoptera - Bees and Wasps, Formicidae - Ants, Blattodea- Cockroaches) provide almost perfect metaphors for the role decentralized biodigesters could play in hunter gatherer landscapes. In fact each individual insect actually is a biodigester, containing the digestive microbes and enzymes in their little guts that does the transformative “heavy lifting”, recycling, concentrating and improving the bioavailability of nutrients, creating a well aerated and fertile landscape.
(See https://www.nytimes.com/2015/03/03/science/termites-are-guardians-of-the-soil.html; see also https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/frontdoor/deliver/index/docId/10700/file/Dissertation_Kaiser_Dorkas_Part1.pdf)
Reconceived as “domesticated termite mounds”, having biodigesters dot the landscape in strategic locations could bring these benefits to the region at a rate commensurate with possibly reversing the bad side of accelerated human impact.
This is an ideal form of biomimicry and already has a precedent elsewhere in Africa through the traditional practice of “zaï farming” or “zaï pits”. Zai farming is a traditional agricultural practice used in parts of the Sahel, including Burkina Faso, to rehabilitate degraded land. Farmers dig small pits, typically about 20-30 cm deep and wide, which capture rainwater and organic material. Termites are naturally attracted to the organic matter in the pits, and their tunneling helps break up the soil, improving its structure and fertility.
The zaï technique works especially well in dry, degraded soils because it creates localized microenvironments where nutrients and moisture accumulate, making it easier for plants to establish roots and thrive. The introduction of termites and ants enhances aeration and helps organic material break down, creating a fertile environment for tree and crop growth.
This method, popularized by Burkinabé farmer Yacouba Sawadogo, was the subject of a documentary film that David Grober and I attended the screening of at the Jackson Hole Wildlife Film Festival over a decade ago. It has proven incredibly effective in combating desertification and restoring plant cover to arid regions.
We suggest that biodigesters could serve similar functions.
In the case of Zai farmers we note that their success comes from creating conditions that attract the natural behavior of social insects, turning them into even more valuable allies to the human condition. Biodigesters can be used in similar ways.
This brings us to the criticism that I and Hanna Fathy, recycling expert from the Egyptian Zabaleen trash recycling community, faced when we were in Kenya and Tanzania training local people to build digesters back in 2010 on a National Geographic synergy grant.
One of the owners of the Great Plains Conservation Lodge where we were partnering with the Masai to do the work suggested that mobile pastoral populations in particular would never have enough organic “waste” residuals to be able to feed digesters in the Boma because they and their cattle basically “ate everything.” He also surmised that because they wander the landscape with their animals there was no efficient way to collect the manure as one might do on the farm.
These critiques resonated with me and recalled my conversations with the Bedouins in Egypt, Jordan and Syria. In fact, as we wandered around the landscape to gather the necessary dung to start the digesters, I recalled wisdom that Syrian bedouins had imparted to me when I visited them in 2001, the year my mother was a Fulbright scholar in Damascus. They complained to me that the farm we were staying on had displaced them and that it was agriculture that was depleting ground water and destroying biodiversity and wildlife habitat and leading to desertification. They laughed at my attempt to defend my veganism and said in an eerie echo to what I was learning in Dr. Hecht’s classes at UCLA about the “metabolic rift” and the “city-countryside disruption”, “your friend's vegetable farm is what is killing the world… it grows exotic thirsty plants and exports all the water and nutrients from our land to other countries and leaves us with nothing. We, on the other hand, move about the landscape with our camels and sheep and donkeys and goats and they eat what humans can’t – thorny shrubs and brush adapted to harsh conditions – and turn it into good meat and milk and cheese and hide and bone and blood that keep us alive and thriving. Our animals take what they have eaten and the water they drink from our wells and distribute it along their paths, making the landscape flourish for when we return.”
This is a narrative we witnessed in Jordan’s Wadi Rum desert (famous from the film Lawrence of Arabia) when I took my wife’s Palestinians tree farming family to visit in the summer of 2023. Wherever the camel trains persisted, now employed to bring tourists to desert campsites for adventures, the desert was blooming with wildflowers and fodder for the animals. Wherever jeeps and trucks were used to transport the tourists the landscape was barren.
Biodigester aren’t easily made mobile like camels (whose stomachs and intestines literally ARE biodigesters) but when strategically positioned along trails they can act in the same redistributive fashion. Biodigesters “pee out” liquid fertilizer making the terrain bloom
The question again turns to, “who would feed them and how?”
And the answer would partially be, “humans… with whatever they/we can hunt and gather”. The feedstock should include or perhaps primarily be made up of, as the Bedouins told me about their animal allies, “things that humans can’t or won’t eat”.
This was an argument I made when visiting the Maya communities of the Yucatan who had pig-waste based biodigesters built by Alex Eaton and his wonderful team at https://sistema.bio/
To use the scalable biogas solution it is recommended households have a certain number of domestic livestock available in a penned space to make it easy to collect the manure. Families without livestock who don’t produce much food waste have not been able to benefit from biodigestion as much, and this is particularly true where pigs are raised and are dependent on whatever food waste the family generates. But we found there is a misconception about what is available to animals – while pigs and certainly goats and camels have a much wider palette than humans and, as Bedouins have been telling me throughout the Middle East for decades, can transform what we can’t or won’t eat into things we can, there are limits.
In the Yucatan we noticed a tree near the pig stye that had been built over the biodigester (with a sloping channel so the manure would be easier to wash into the digester and radically reduce labor) that had dumped a prodigious amount of fruit on the ground. The fruit was uneaten and left to rot. Why? Because, we were told, “it is poisonous”. Many many plants produce fruits, seeds, husks, skins, leaves and other parts that are toxic to various organisms because this, along with thorns and bark, are how plants, being sedentary, defend themselves from predation. But while these protective toxic molecules are hard for animals to safely digest, most of them can be broken down by the microbes living in biodigesters who are not dependent on the cellular health of a host animal. The domestic dragon or termite mound doesn’t have to keep its “skin” alive. The microbes, which can in many cases reproduce in as little as 20 minutes, EVOLVE to adapt to the feedstock introduced to them. This means that one can “train your dragon” to consume almost everything you can hunt and gather that would otherwise be useless to you and your animal allies.
In the case of the proposed distributed “domesticated termite mound” type biodigesters we can conceive of the Hadza moving about the landscape with carrying sacks, gathering that which is useful for their families in one and gathering that which could feed the digester in another, redistributing resources in the most beneficial ways. In this way the Hadza, working analogous to social insects like bees, would consider the digester as a “hive” and would gather the “pollen” and “nectar” to make “honey”.
Since the Hadza are among the worlds most celebrated honey foragers and understand bee ecology intimately, this metaphor could help the integration of biodigesters in the landscape take on great significance. The Hadza would be the metaphorical bees and the “honey” the digesters produce would be in the form of land fertility and literal nectar – particularly prized wildflowers that real bees could in turn benefit from, enhancing the real honey production potential. Each time the Hadza put organic material into the digesters along the path the digesters would passively drip out liquid compost to support flowering plant growth around it.
But in addition to humans hunting and gathering feedstock for the digester (which would be IDEAL for the non edible remains of hunted animals – guts and intestines would add the necessary microbes that drive the process and non-useful parts of hide or skin or bone or organs and intestinal fecal contents would act as great feed and fiber for the digester!) we could harness the insect biota in much the same way Zai farmers do, encouraging insects to come to the digester (using different attractants and possibly even a solar charged bug zapper as they used to do at the New Alchemy institute to passively feed their tilapia!).
I was introduced to soldier fly breeding areas (netted enclosures where animal carcasses and rotting food are left with portals for the flies to get in and out to lay their eggs) in Nigeria by former president Obasanjo. He used the larvae produced as a high protein food for his tilapia. At Rosebud we have a soldier fly breeding container for feeding our chickens that founder Maryann Bishop demonstrates in this video:
https://www.youtube.com/watch?v=Aa0hsm0HmX8
Many ways could be adopted for encouraging the growth of insects and worms and other “r-selected” fast growing and “pest” animals that could be trapped and fed to the digesters (including mosquitoes and their larvae, biting flies, roaches, beetles, moths, rodents etc.) so that the digester locations along the trails could be, in a sense, “self-feeding”. Similarly, fruit trees (even those producing inedible fruit) could be planted above the digester with some fruitfall funneled into the tank. Inedible or spoiled fruit could be directly gathered and dumped in the digester for a no loss scenario where nutrients are produced that could more rapidly be turned into nutritious soil that if simply left to rot.
Certainly the “rest stops” where the biodigesters would be built could use them as “liquid composting toilets”. Recall that the Chinese traditionally invited people to visit roadside stalls next to their farms to eat and to use their composting toilets. They called the organic material they collected from these roadside attractions “night soil” and applied it to their fields. They were, in effect, taking advantage of travelers on the roads to supply them with much needed nitrogen, phosphorus and potassium (NPK) and other components of fertilizer which were otherwise expensive or in short supply. In a similar way the Hadza could use the distributed digesters to reclaim nutrients from their own “humanure” as well as that of tourists, and when/if they do bring tourists to their land, they could take advantage of any food or beverages the tourists bring in from outside – using both the inedible or uneaten portions and that which passed through the bodies of the tourists. This would make eco-tourism activities a net gain to their environment (rather than the net loss that farming or non-native hunting normally represents – everything removed from a landscape and taken away for sale in a market or as a trophy exacerbates the “metabolic rift”; any time people bring nutrients into an area we are closing the rift.) Creating "trashart" to enhance the beauty of the landscape with the rest of the "waste" materials.
Using the “trashcrete” technique developed at Rosebud Continuum by Dr. Culhane, even the plastic, metal, glass, cardboard and paper packaging brought in by tourists could be turned into a net benefit to the Hadza community. Dr. Culhane has demonstrated that when shredded and granulated using “precious plastic” machinery and glass crushers (which could be located at the Hadza school being built), twenty 30 gallon totes of “garbage” are reduced to two or three totes of plastic shred and glass cullet sand. These materials, infused in cement or lime or sodium silicate as a binder (using a ratio of about 1 part cement or other binder to two parts plastic shred and 2 parts glass cullet sand) create enough material to build sculptures roughly 2 feet tall by 4 feet wide by 4 feet long. This would be sufficient to decorate an IBC tank digester, for example, to look like a termite mound. Once painted with a coating of earth, glass cullet and a little binder it should look fairly indistinguishable from a real termite mound or rock Kopje (think of how imagineers have decorated Disneyland parks like Animal Kingdom to look like African wilderness using a similar material they call “shapecrete”).
Below are pictures from a tourist who went to Animal Kingdom in Orlando Florida and photographed the “fake” termite mounds and rocks and even Baobab trees made from shapecrete:
We have shown at the Rosebud Continuum Eco-Science Center that similar structures can reliably and simply be made out of shredded and crushed recycled trash without needing any sorting or preparation (including chips bags and candy wrappers etc.). See https://www.rosebudcontinuum.net/recycling-repurposing
It is our hope that we can meet with representatives of the Hadza in the near future and discuss this proposal and find a way to start a pilot project to demonstrate the efficacy of the concept.
In the meantime, we at Rosebud Continuum and the Patel College of Global Sustainability at USF Tampa will continue to life-test, experiment with and prove these ideas at our field center, exploring the feasibility of implementation in the hunter-gatherer/nomadic context and constantly thinking through improvements.
We will also start working on a handbook/manual, a video series and animations that can be used for remote learning interconnection and can be translated into Swahili and regional languages/dialects:
Concept:
Chapter 1: "Nomadic Wisdom Meets Microbial Innovation" This chapter would delve into the Hadza’s traditional ways of living and how the nomadic lifestyle and ecological wisdom align with modern biogas technology. It could highlight the blending of their deep ecological knowledge with the microbial innovations biodigesters offer.
Chapter 2: "Harnessing the Microbiome: Biogas as a Path to Ecological Harmony" This part could explore the microbial consortia within biodigesters, likening them to the invisible helpers or ‘domesticated dragons’ that transform waste into energy and fertility. It would focus on the microbiome's role in ecological balance and health, drawing parallels to the Hadza’s own practices of engaging with natural systems for health and sustainability.
Chapter 3: "Strategic Nomadic Energy: Biodigesters Along the Hadza’s Trails" This chapter would cover the idea of placing biodigesters along nomadic paths, addressing how the Hadza could benefit from renewable energy without becoming sedentary. It could also discuss how biodigesters can promote fertility along trails, in harmony with the environment.
These chapters could come together under the overarching theme of Guardianship, emphasizing how ancient wisdom and modern microbial innovation can forge sustainable paths forward jointly.
To get familiar with the Hadza see:
https://www.nature.com/articles/ncomms4654
This has a map of their range.
Here is a National Geographic piece on the Hadza and their geography:
https://www.youtube.com/watch?v=ak7BChSquoo
Also see
https://www.youtube.com/watch?v=tRIW0GPD4FY&t=250s
This video shows the struggle for their land rights.
Learn about the B-energy portable biogas backpacks and low cost digestors in Ethiopia here:
https://be-nrg.com/learn-about-biogas/
These are the GPS coordinates of their region:
-3.7369807656557437, 35.20585305144406
https://maps.app.goo.gl/kqvqgLanrXtB3xXLA
Learn about the importance of fat in the diet of the Hadza from this Harvard study review here:
https://peabody.harvard.edu/audio-evolution-big-game-hunting-protein-fat-or-politics
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Student notes:
Make policies and regulations with the officials and government to maintain the eco-friendly environment.
Maintaining the carbon credits selling and investing in the facility (school, hospital, and learning center)
Sustainable tourism is good, but some rules and regulations need to be limited. Bhutan, for example, makes tourists follow its environmentally friendly areas.
https://borgenproject.org/sustainable-tourism-in-bhutan/
High Value, Low Impact
Sustainable Energy (for example biodigester/ renewable energy such as solar power cookers)
Using the concept of agroforestry, they can Encourage the planting of fast-growing, multi-purpose trees that can be used for sustainable firewood while also restoring ecosystems. These systems can be combined with crops to create a sustainable land-use model that provides food and wood over time.
Education and Training: Providing education on the environmental impact of deforestation and teaching alternative livelihoods, such as sustainable farming, agroforestry, and other nature-based solutions.
Waste management from tourism, zero waste concept/ composting using food waste from the tourist (composting /Bokashi project) https://bokashiliving.com/
Tourist can do carbon offset program where they can have tree-planting initiatives. (community-based tourism) eg homestays
Sustainable Livelihoods
Agroforestry as a Long-Term Investment: Promote long-term tree cropping (like fruit trees, timber, and medicinal plants) that provide steady income while restoring ecosystems.
Eco-friendly products selling eco-friendly products from natural or recycled materials, giving tourists souvenirs that align with sustainability principles.
