This Startup Wants to Turn Diaper Waste into Fruit Trees
Dycle's first fruit trees. Photo courtesy of Aymi Mastuzaka.


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This Startup Wants to Turn Diaper Waste into Fruit Trees

German startup Dycle, founded by artist Ayumi Matzusaka, aims to tackle the massive amount of diaper waste produced each year by converting it to nutrient-packed soil and planting fruit trees with it.

On a warm, late-summer afternoon in the garden of Eden—the Eden Café garden that is, where wildflower hedgerows buzz with bumblebees, apple trees are laden with shiny fruit glinting in the sun, and a small woman lugs a massive branch to a blazing fire pit—a biochar workshop with artist and social startup innovator Ayumi Matzusaka is underway. In her works, Matzusaka is inspired by the nutrient cycle and not wasting waste. She hopes to apply this circular theory to the production, use, and recycling of used baby diapers for her newly launched startup Dycle, which aims to tackle the waste problem of the diaper cycle. Matzusaka notes that by the time a child is three years old, they will have produced 500 kilos of diaper waste.


Artist and Dycle founder Ayumi Matzusaka with one of her first fruit trees grown with terra preta. Photo by the author.

As part of this bigger plan to address waste, Dycle is leading small community workshops like today's, showing how to produce biochar—essentially charcoal—a soil enhancer and one of the important steps in the ancient method of producing terra preta, also known as black or fertile soil. What would Dycle like to convince us to use in the production of terra preta? Used baby diapers.


Terra preta made from diaper waste and biochar.

"You start with a bucket and then layer this biochar powder with any organic materials—kitchen waste, coffee grinds, or used diapers—it's the same. For example, I did a project with my hair, nails, grass, cow manure, chicken manure," Matzusaka tells me. Fill the bucket to the top and wait four weeks. During this fermentation time, microorganisms multiply, then it's time to call the worms in for dinner. The fermented layers from the bucket are mixed with soil, and it becomes aerobic, and worms come to eat. The length of time involved depends on the organic material: for kitchen waste in summertime conditions, fermentation could take two months; during the winter temperatures in Germany, it would take a longer time. If human waste—i.e, used baby diapers—is the organic material, Matzusaka recommends waiting for one year; she explains that you typically need to wait two to three years if you do normal hot-composting, for hygiene reasons. For terra preta, Matzusaka claims that one year is enough time because the microorganisms, fungi, and bacteria work intensively on the organic materials.


Well-fed worms are happy because they eat microorganisms—and will then produce six times more microorganisms in the final stage of terra preta production, during the worm composting. Microorganisms are essential for healthy soil, while biochar helps soil to retain nutrients and can be used to address food security in areas of depleted soils. Compared to those grown in our current depleted soils, "fruits and vegetables grown decades ago were much richer in vitamins and minerals than the varieties most of us get today," according to Scientific American.


Dycyle buckets for creating terra preta. Photo by Ayumi Matzusaka.

Matzusaka is currently inviting parents with young children to participate in a closed loop of waste and growth, which starts with creating terra preta by composting organic materials such as kitchen waste—or as Dycle hopes, used biodegradable diapers—with biochar and natural bacteria that encourages the composting process. biochar also helpfully neutralises the smell as it composts. Terra preta should not be mistaken for compost or fertiliser, Matzusaka says. "You don't need compost if you are using terra preta. We make terra preta substrate—it is not compost."

Dycle is supported by Gunter Pauli, the founder of the "Blue Economy," a business model that encourages society to live in a more sustainable way, "to use the waste of one product as the input for another." Matzusaka notes that she often works with scientists in her work, too. "I got the idea, Can I make my own soil, personal soil?" she explained. "I reached out to scientists as I like to do for my art projects, and found out about terra preta, a promising method [with which] we could produce very rich soil from human excretion." The Dycle crew includes Dr. Pieplow from the German Federal Ministry of Environment, Dipl. Geogr, Kathrin Rößler and her team from Berlin's botanical garden, and microbiologist Prof. Dr. Michael Weiss.


Matzusaka has incorporated waste into her other work, such as a beer made from barley fertilized with human urine. Photo by the author. The "Kon-Tiki" kiln. Photo by the author.

If Dycle can persuade parents to initially get into a routine of collecting their kitchen scraps and regularly dropping them off at a collection point, they hope convincing parents in the community to do the same with used baby diapers won't be too big of a leap. The circle is complete when the terra preta is used as a planting soil for fruit trees, with the hope that the future generation, which originally contributed the waste, will consume these fruits.

Back to the blazing fire pit: Soil expert Dr. Haiko Pieplow is on-hand to lead the workshop, explaining that this age-old tradition has been used for thousands of years as a means of improving soil.

First, we collect dry branches and twigs from the surrounding area. The wood is lit on fire and burned in an open-fire, cone-shaped biochar kiln dubbed "The Kon-Tiki."

A pyramid of wood is set up with larger pieces at the bottom to prevent smaller sticks from falling through the grating at the bottom of the kiln. Additional wood should be added to the fire once white ashes begin to appear on the burning wood.

The shape of the kiln is crucial as it helps air to circulate through while the wood is burning, creating a vortex that helps to bring air down through the layers of burning wood. The flames and updraft from the newly added layers of burning wood prevents air from reaching the biochar that has already been created and settled below the burning fire. Once the charring is complete, the fire is doused with water, washing away any ashes, and what remains is biochar. Our workshop produces 80 litres of the stuff.


Hot ashes leftover from creating biochar are used to heat a makeshift stove in a washing machine drum. Photo by the author. Eggs and mushrooms cook on the ashes.

While the fire is burning in the kiln, the temperature reaches a whopping 600 degrees Celsius. Christian Schloh from the Dycle team explains that because we are in Germany, however, we are only allowed to burn a garden fire for celebration purposes. Our solution? We celebrate learning about biochar with Ayumi's mung-bean pancakes, miso vegetable soup, fried eggs, and toast. Hot ashes from the kiln are transferred to a smaller recycled washing machine drum which serves as a heat source for our wok. To cook the miso soup, we dig holes in the ground and fill them with hot ashes from the fire, resting a dutch oven full of vegetables and miso broth on top of the ashes, with even more ashes were piled on top of the lid. Dr. Pieplow tells me these ashes were around 200 degrees Celsius, and they remain hot enough to cook the soup for over half an hour.

Eighteen of us tucked into the delicious food, everyone going back for seconds and thinking, Hey, I could do this at home. Biochar isn't that hard.

Matzusaka has incorporated waste into her works throughout her career as an artist, from her 2002 work Traces of Existence, in which she spent a year collecting 8,000 tea bags or "time traces" from 80 households, to her 2010 project All My Cycle, in cooperation with a local Berlin urban gardening centre.


A well-rounded feast made with leftover heat from the biochar-making process.

"I started the nutrient cycle project as an artist in 2010," Matzusaka told me, "I collected 70 litres of my urine and transformed it into black soil—the terra preta—working with biologist Dr. Juergen Reckin. I grew salad and vegetables at the Prinzessingarten, and then ate my own salad, out of my own body."


These projects led to Future Beer, Matzusaka's beer production project commissioned for the Dortmund Neu Gold exhibition in 2015, which involved collecting urine to be used as a nutrient to grow barley. Matzusaka also ran the project at the same time in Berlin, with the help of the Botanical Garden Berlin-Dahlem and local urban gardening project Prinzessingarten. After a tasting with a selected crew of craft brewers, Matzusaka collected 30 litres of urine from participants. In the Botanical Garden, a plot of barley was watered with diluted urine and later harvested, malted, and brewed into bottles of Future Beer. Finally, to complete the circle, the beer was served to the original contributors.


Matzusaka with her Future Beer.

The global baby care market could be worth up to 70 billion by 2017, and pressure from diaper producers could be a major obstacle for a startup like Dycle. However, Dycle does not want to produce diapers or attract investors, nor does it plan to sell the terra preta black soil, or the fruits harvested from future trees grown with it. Rather, Dycle is interested in companies that could invest in the diaper cycle by purchasing the fruit trees, or by participating in planting workshops with employees.

Crucially, Dycle also need parents to sign up for diaper dropoff, the first group of which is already growing in the neighbourhood of Pankow, Berlin's most populated borough. The first fruit tree planting is also scheduled to take place this November in Berlin, using terra preta from the Dycle pilot project with 20 families and their respective used baby diapers. Dycle is already working with a sustainable diaper company and is searching for more such partners after rigorously testing every available so-called compostable diaper on the market. ("None of them decomposed fully," Matzusaka tells me.) The startup has also partnered with a local CSA in Berlin, Food Assembly, where customers collect weekly produce from the Berlin local area. Through the Food Assembly, Dycle has been able to organise the collection of the kitchen scraps, to initiate the first steps of the introduction process to the terra preta process.

Soil away with me, honey…

Every day this week, MUNCHIES is exploring the future of food on planet Earth, from lab-grown meat and biohacking to GMOs and the precarious state of our oceans. Follow along with us here.