Advanced composting process – The Johnson-Su Bioreactor

In our endeavor to produce a highly diverse and rich compost for regenerating our soils, we have included an advanced technique called “Johnson-Su Bioreactor”. This composting method has been developed by molecular microbiologist David C. Johnson and his wife Hui-Chun-Su. They were looking for a composting system low in salts, presenting a high fungal bacteria ratio, low maintenance, and able to boost crop growth. That’s how the Johson-Su Bioreactor was born.

Some of the main advantages of the Bioreactor are that it’s made with easy-to-find materials, it’s cheap and doesn’t require maintenance once built and filled. In fact, we don’t disturb the composting process, allowing fungi to spread and colonize the pile. The Bioreactor is made of metallic mesh, used in the construction industry or for fencing, landscape cloth, a pallet, and perforated plastic pipes (10cm diameter), though they are only used for one day.

Volunteers Roberta and Christian, helping us with the levelling of a wooden base for two bioreactors.

Picture at the left: Chris is setting the plastic pipes for aeration. These pipes keep the Bioreactor with oxygen at the beginning of the process.

After the first day, fungal hyphae (the filamentous structure of a fungus) are already set in the pile so much that you can pull the pipes out. The six vents will stay open and allow air to flow up from under the pallet, which is slightly elevated, keeping an aerobic environment.

We gather material some days before the construction of the Bioreactor.

Picture at the right gives an overview of the working station where we soak the carbon material (woodchips) and the nitrogen-rich material (cow manure).

The materials should be completely wet before starting to fill the Bioreactor.
Starting to fill the pile
View of materials and tools
Bioreactor half filled

The most important thing is allowing it to mature long enough — for a year. Yes, one long year! but the final material obtained through this process is really worth it.

Picture at the left: view of the Bioreactor once filled and with the plastic pipes.

As we add the carbon and nitrogen-rich materials, the pile starts heating up for a couple of days.

Microorganisms start reproducing and generating heat quickly.

Also, moisture is a very important aspect of keeping the pile under ideal conditions for the microorganisms to thrive. The pile should keep a moisture level around 70% so the installation of an irrigation system is recommended.

You can find all the instructions from New Mexico State University here.

As we are curious people, 4 months after building the bioreactor we took a look at the partially composted material under the microscope and the results were outstanding. The diversity and richness in microbiology were amazing (some pictures below).

We will use the final compost, after a year, as an inoculant for compost extracts, compost teas, and as mulch around the trees. We also see this material as a perfect complement to one of the most useful techniques in regenerative agriculture: cover crops!
Cover crops will feed the microbiology coming from the Bioreactor with sugars produced during photosynthesis (root exudates), and all together will regenerate the soils and the health of plants and trees.

Why do we love to see fungi in our land?

Our biggest interest in this Bioreactor is the fact of avoiding any disturbance, being high in carbon materials, and therefore, creating a perfect environment for fungi to thrive and grow.

Yes, we love to see fungi in our land!

Unfortunately, since the beginning of conventional agriculture in the early 20th century, agricultural practices have been extremely detrimental to fungal communities.

These fungal communities are essential to get healthy soil as they support the nutrient cycle of plants, making nutrients available (through powerful enzymes), establishing synergies between fungi and plants (exchange of sugars produced through the plant photosynthesis, called exudates, and water and nutrients provided by the fungi) and, last but not least, sequestering carbon by the formation of complex humic chain molecules in the soil.

Most of our soils are bacterial-dominated with almost no presence of fungi, meaning that the fungal-bacteria ratio is very low. This implies that in some cases, even more than 95% of the carbon (sugars) captured by the plant through photosynthesis goes to the soil to feed the microbial communities. However, in healthy soil, where fungi are present and therefore the fungal-bacterial ratio is higher, the plant only needs to send around 40-50% of the carbon to the soil keeping the rest of it for its own growth and development.

No wonder it makes us very happy when we see fungal hyphae in our soils with the help of our microscope.

And just a final note…

Science is unable to understand all the processes happening in the soil through the interactions between different microbial groups and quite often it uses a linear way of thinking, unfortunately. However, what seems more and more clear is that an increase in the diversity and presence of these groups can be translated into a higher resilience and strength. That’s why it’s so important to use tools like the Bioreactor to add that diversity.
In the same way, human health is dependent on the diversity and health of our microbial gut communities. Interesting, isn’t it?

Could the understanding of how the soil works help us to understand how the microbes in our guts interact and work for us, or vice-versa?

While we try to answer this question, we will continue taking care of our soils with the help of powerful microscopic armies produced in bioreactors and other composting processes, as we will continue taking care of ourselves by eating quality food produced in healthy soils.

Building our composting area

Compost production is at the heart of our regenerative practices and having a proper space to produce it seemed an important milestone in our journey.

It all started from the wish to professionalize our compost production. At the beginning, we were making our compost outside, having to protect our piles from sun, wind, and rain.

Hot compost production outdoors

A fully covered area would give us the benefit of working in the shade and protect our fresh piles and the finished product from too much heat, wind or humidity. All of which contributes to a better product in the end: a rich, dark compost, that is full with microbial life.

It all starts with a rough sketch…

So, the task at hand was to construct a spacious, covered area that would allow us to have more control over the entire process while making our lives a bit easier at the same time.

We always try to design our systems with a permaculture approach – each element performs many functions. Thus, the new building should not only help us to produce compost, protect us and the compost from the elements but should also integrate in the existing systems. That’s why the “relative location” of each element is crucial.

By placing it right next to (and one terrace level up from) the main garden, we can choose to gravity-feed our veggie garden by connecting the liquid compost tank to the irrigation system. This way, we save ourselves a lot of time and effort.
Future plans involve adding animal stables right next to the compost area, which is another example of a “relative location“. The need for fresh manure in our compost production makes the placement of animal stables right next to it a smart choice.

The building process

After having found the right location, we started out with a rough sketch, some measuring, and the help of many volunteers. We had to select the right logs for the pillars, shave the bark off of them and bury them 1m deep in the compacted clay soil.

First task completed: Coco and Chris are celebrating the accomplished burying and aligning of the pillars

Now that the pillars were in place, we started to connect them with horizontal crossbeams. On top of these connectors, we had to fix other logs using simple joinery. Even though it was basic woodworking, the irregularity of roundwood has got its challenges. Nevertheless, we were determined to spend as little money as possible (as opposed to buying more processed – meaning square – pillars and beams) and we simply love the “rinky-dinky”-style of building with roundwood.

As soon as the main structure was up, we could cover the roof. We decided on rough boards from locally sourced Douglas firs.

To protect the roof from rain, we used overlapping rows of tar paper. We heated the tar paper at the edge where the rows overlap in order to glue them together properly.

Finally, it was time to take care of the work area itself. After some debating whether to use cement or not, we’ve decided to pour a cement floor for half of the building.

We wanted a flat and clean workspace for storing the finished compost and more importantly, placing the brewing tank for our liquid compost production.

We boarded up the walls on the two “wheater sides”, to protect from winds and precipitation from north and west. Leaving enough space on top of every wall would grant us enough natural light and also lessen the wind pressure on the structure.

All we had to do now was installing water and power lines and build a wooden platform to carry our 600lt tank. We’ve also included a ladder and service platform on top of it to be able to easily access and clean the residues inside the tank after each brewing process.

We’ve already used it many times and it works perfectly!
The elevated platform provides some altitude to empty the tank without any pump or power, simply using gravity.

Mario and Flo are filling the containers with freshly brewed compost extract
The finished composting area

In the future, we’re planning to install a wind turbine and batteries to hopefully generate enough electricity for the air pumps, which are needed to produce a high-quality liquid compost (tea & extracts).

Another future project is to harvest the rain water from the roof to further minimize the environmental impact in our compost production.

Surely, we’ll be looking for the best possible “relative location” of the rainwater catchment system to ensure that it’ll be also adhering to the permaculture principle of “each element performs many functions”.

For now, we’re super thrilled to be able to work efficiently and produce one of our main assets, a dark, rich, microbially active compost in larger quantities.

This will speed up the regeneration process of all the parts of our land, be it the olive groves, the food forest, or our veggie gardens.

Building an eco-friendly campsite

In the following article, we’ll walk you through the building process for our eco-friendly campsite. We have completed two super comfy and easy-to-service compost toilets aka “the temple of poo”, two “yin-yang” shaped outdoor showers, a spacious washing station, and a social “chill-out space”. It is eco-friendly because every drop of water is being put back into the cycle and re-used. It all turned out quite as we envisioned it and – even after a year – we’re still very happy with the outcome.

When we decided to organize the “natural building workshop” in September 2020 we knew that we had a few weeks of hard work ahead of us to build a comfortable camping area to accommodate the needs of 12-15 students. It was quite a challenge, having to build all that within the hot month of August!

And we had to start from scratch: There were only olive trees, a small meadow, and a ruin.

But with the help of our volunteers, especially René, Markus, and Nina, we started to transform the area quickly into something else. First, we installed a small outdoor carpentry from where we’d build all the components for the dry toilets, the showers, and the washing station.

View of our temporary working station on the small meadow.

Compost toilets aka “Temple of Poo”

Our first priority for the compost toilets was durability and comfort. We wanted to create a structure that would last over time and could comfortably accommodate two people at the same time (in different compartments, of course 🙂 ).

Also, it should be easy to service and clean in an efficient manner.

The location we chose for the compost toilet would have to contribute to this latest aspect. We found a perfect spot that was close enough to the tent space and offered two different altitude levels.

The reason for building the structure across two levels is that on the upper level you’ll have convenient access to the toilet spaces while on the lower level you’ll get easy access to the maintenance area with all the bins and containers. This way, comfortable usage is guaranteed for both the visitors of the toilets and the maintenance crew (us 🙂 ) to do the weekly cleaning routine.

In this image, we can see the two levels under construction. The bottom part is the space for the bins and containers. The upper part holds the two toilets and entrance.

As soon as the site was chosen, we started with the foundations for the main pillars. In this case, we used a cement / gravel mix mainly because our focus was on durability and also because there is a high risk of erosion around a terraced ground that consists mainly of sandy soil.

Chris fixing the wooden pillars on the concrete foundation.

After the foundations had dried, we started constructing the wooden structure and raised the nine main pillars.

View of the main structure set on 9 point foundations. The two wooden steps leading up to the toilets from ground level are already in place.
First “test-drive” of the sitting platform 🙂
View of the wooden structure with the first separating wall.
Frontal view of the two cabins with lateral walls finished.
We recycled 2 old green windows. They grant a beautiful view of the village and bring personality to the building.
Mario helping with calculating the roof angle.
Cutting the pieces for making a super comfy toilet seat.
Frontal view of the building without the roof.
Chris using the chainsaw to cut the roof support at the right angle.
A proper tool for each task will save a lot of time.
Frontal view of the building with the roof.
View of the back with the two green windows at the top and the “maintenance area” at the bottom. The urine containers are still missing.

Luckily, we were able to reclaim both doors and windows from a derelict house which are giving the building a unique touch. In the end, we oiled the whole wooden structure (Douglas fir) with linseed oil to protect it better from rain.

One of the main reasons why the compost toilet works so well without generating unpleasant odours was the separation of liquids and solids in the toilet. A urine separator ensures that the faeces do not get the excess moisture and can therefore dry quickly without generating unpleasant odours. Another huge plus is that we can safely compost the precious “humanure” (feces) and use the urine diluted with water as a high-nitrogen liquid fertilizer for our olive trees.

For its size, lasting materials, and efficiency we decided to call it The Temple of Poo 🙂

Yin & Yang Showers

One of our first ideas was to build two intertwined outdoor showers in the shape of a drop or the Yin and Yang symbol (which can only be seen from a bird’s perspective).

However, we soon realised that some modifications had to be made to the original shape to make it functional and to be able to enter and leave the “maze”.

Following the permaculture principle, “Each element performs many functions” (at least three), we had set our minds to a solution that would allow us to reuse the greywater from the showers and circulate it through our land as long as possible. From a permaculture perspective, the showers are not only cleaning our guests, they also inspire us with their beauty and most importantly, they’re also helping us to irrigate our citrus trees.

We knew that this would require some sort of cleaning process before we could use it for irrigation. Read on and discover the step-by-step process of constructing the showers and the reed bed to filter the water until the moment when we finally could wash the sweat and dust off of our happy faces when the showers were finished.

It all started with a hole of about 4m in diameter.

René helped us in making the hole. We can see the mix of sandy and clay soil found in that spot.
View of the future shower area.

In the middle of the two showers, we installed a drainage system and a pipe that would transport the greywater towards the reed bed.

René covers the pipe which connects the showers with the reed bed. The wooden boards were used as an independent base for the walls.

We laid out a 4x4m pond liner (black waterproof plastic) to collect all the water from the two showers. Then we topped it up with gravel until the ground level was reached.

View of the hole covered with the pond liner.
We added gravel onto the pond liner.
In the middle you can see the drainage box for collecting the water.
View of the support structure for the poles. The water input pipes can also be seen in the middle.

Once the water collection system was almost done, we proceeded with the installation of posts to support the walls of the showers. Since the pond liner couldn’t be pierced or damaged, we had to construct a stand-alone wooden structure where the walls could be attached to.

After the structure was finished we covered the boards with gravel.

For the shower walls, we chose the local variety of cane, as it grows abundantly in this area and is available freely all year round. Each of the canes was cut to a certain height (around 2m) and a couple of holes were drilled in the ends of the cane. 

Then, a wire rope was inserted through the holes to give consistency to the wall and to join cane to cane.

Working station for creating the cane panels.
View of the first meters of wall installed.
We included a line of stones where the canes could be rested upon.
Just one missing panel…!

Once the walls were done, the only thing left to do was to connect the shower heads with the pipes coming from the ground. For usability and comfort, Nina has built a small wooden bench for each of the shower compartments.

Detail of the shower.
Done! For more comfort and beauty we’ve hand-picked some smooth stones from the beach
Bird’s eye perspective:
A slightly opened Yin-Yang shape allowing to access both showers independently.
View of the “Temple of Poo” and the showers

Washing station & Laundry

Last but not least, we also needed a place for our guests to wash their clothes, brush their teeth, and, basically, have access to water.

From reclaimed local chestnut wood, Nina built a beautiful wooden table with a double sink. On the extension to the left, we managed to integrate an old washstand that we had found in the trash. 

View of the wooden table with the sinks still under construction.
View of the completed washing station with the old concrete washstand.

Of course, we also connected the greywater pipe from the washing station with the reed bed.

We didn’t want to waste a drop of our precious water!

Chill-out area

Creating a space for people to relax and socialise after work was the last of the tasks. We thought that our ruin, a halfway collapsed former farm building, would serve that purpose.

So we started to clean the inside from all the wild vines, brambles and leveled the ground. The half-open walls protect the interior just enough from wind gusts, creating a nice comfy space which we’ve completed by adding a couple of tables and wooden benches.

We’ve also included a light chain for late-night sessions and, most importantly, a power socket for the students to charge their devices.

Finally, we included a sun sail to create some shade for the rare occasion of rest during the day.

View of the “chill-out” space inside the ruin

Luckily, everybody was as excited as we were about our new campsite facilities! We didn’t have to wait long before we’ve got some positive comments from our guests.

Among many others, we remember the happy face of a student exiting the showers. He came out with a broad smile from ear to ear saying:

“This shower experience has been amazing, I simply love the natural vibe of it”.

But not only us humans enjoy the benefits of a well-designed campsite. Remember: From a permaculture perspective, each element should have multiple functions. In this case, our trees and gardens also benefit indirectly from these facilities as the faeces and urine, generously produced by our guests, are being used as fertilizers.

In the case of urine, we get a ready-to-use, nitrogen-rich fertilizer (diluted 1:10 with water) while we prefer to let the faeces aka “humanure” decompose for at least a year before we use them as an amendment / organic matter for our trees.

We feel proud of managing our campsite in a sustainable way and hope that all our future guests will be equally happy knowing that the water they use or their “left-behinds” in the compost toilet will eventually be reused and put back in the big cycle of life.