CCB Magazine

Eco-toilets have been used at festivals for some time. Now, urine-diverting dry toilets are the latest trend: they save water, resources and are good for the environment. Finizio makes such toilets, based on the cradle-to-cradle principle - and turns human excrement into quality humus. We spoke to Jolanthe Stelzer from Finizio about strategy and concept. 
 

INTERVIEW  Boris Messing

CCB Magazine:Hi Jolanthe. You work for Finizio in design and public relations. How are Finizio's eco-toilets different from other suppliers?

Jolanthe Stelzer:Our unique selling point is the recycling of solids into quality-assured humus fertilizer. To this end, we operate the pilot plant, which is currently unique in Germany, where we have been fine-tuning the process of controlled oxygen-supplied composting and the quality of the end product since 2019. Other composting toilet companies such as Goldeimer also deliver to us to have the toilet contents recycled. 

CCB Magazine:When it comes to eco-toilets, the terms dry toilets and urine-diverting dry toilets usually come up. What are the differences? 

Jolanthe Stelzer:Dry toilets use a litter flush instead of a water flush. The litter covers the leftovers to minimize odors and hide them from the next guest. With urine-diverting dry toilets, urine and feces are collected separately. For example, the urine flows through a funnel into a separate tank. As a rule, the solids are also covered with litter in a urine-diverting dry toilet - which is why these are then often referred to as dry toilets. 

CCB Magazine:And what makes your toilets special? 

Jolanthe Stelzer:Unlike chemical toilets like conventional porta-potties, we do not use chemicals and instead rely on a litter flush; this consists of straw granules that are later processed with the feces into humus. While the festival toilets are strewn by hand, we offer a strewing dispenser with a rotary knob for all other products, which makes the process easier. In addition, our festival cabins are stackable. This allows us to reduce transport distances. And by processing the manure into quality humus, we bind carbon. In this way, we save valuable drinking water overall, Co2 emissions and return the nutrients to the cycle.

We use foldable and stackable dry toilets for festivals and events - this way we stack 40 toilets on the area of a marriage bed. This saves transport distances and thus Co2

CCB Magazine:Okay, let's be specific: I'm a festival operator, I want to be sustainable and I'm interested in your eco-toilets. How does the process work? 

Jolanthe Stelzer:We offer you an all-inclusive service, including our so-called Kakastrophenschutz: from the construction to the cleaning to the dismantling and transport and the recycling to the recycling fertilizer, everything is included. Of course, we also offer this service for our products in private and public areas. While the festival cabins remain a pure rental property, some toilets and cabins in the public and private segment can also be purchased.  

CCB Magazine:What different products does Finizio offer?

Jolanthe Stelzer:We have developed three different separation systems: First, the PeePot with the teapot effect, where the urine runs along a stainless steel arch into a drain hidden underneath. Second, in our foldable and stackable festival toilets, we use a subsequent separation by means of a drainage and pumping system - in this way, we stack 40 toilets on the area of a marital bed. The third system is still under development and is being developed as a separation toilet for multi-storey residential buildings. Separation and recycling of excreta is the focus of each of our toilet systems.

CCB Magazine:Your systems are based on the cradle-to-cradle principle, according to which everything should be returned to its origin. Your toilets were recently used at the Tempelhof Laboratory, where the Ärtze and the Toten Hosen played. What other festivals and cultural events have you worked for? Is the demand growing?

Jolanthe Stelzer:Yes, the demand is growing and our team has also expanded quite quickly. Meanwhile, we have already supplied a lot of festivals and cultural events. To name just a few from this year: Fusion, Re:publica, then the aforementioned Labor Tempelhof, plus the Southside Festival, Feel Festival and many, many other festivals. Now in winter we are producing and we can hardly keep up.

Top: The foldable and stackable toilets. Bottom: This is what they look like when lined up. Photos: Finizio GmbH.

CCB Magazine:Let's go into detail. You said that you are operating a pilot plant in cooperation with Kreiswerke Barnim to turn human feces into quality humus that can be used for agriculture. How do you turn shit into humus, to put it casually?  

Jolanthe Stelzer:The contents from the dry toilets are placed in a sanitizing container for at least one week. Here, microorganisms combined with an air supply generate 70°, causing bacteria such as salmonella, etc., to die. The contents are then mixed with aggregates such as green waste, clay minerals and plant charcoal and placed in a long pile. Regular turning, i.e. sufficient oxygen, moisture and temperature regulation, produces a quality-assured humus fertilizer within eight weeks.

CCB Magazine:Follow-up question: When the feces are heated in combination with the air supply, all bacteria are killed. But doesn't this also kill the microorganisms that are necessary for humification?

Jolanthe Stelzer:Yes, many microorganisms die during sanitization. That's why we then add clay minerals, plant charcoal and about ten percent finished compost, which already contains the right microorganisms for humification. In technical jargon, this is also called giving an inoculation.

Excrement goes into this container (top), then is pulled into an elongated pile (middle), enriched with nutrients, filtered, and in the end, quality humus (bottom) comes out. Photos: Finizio GmbH.
 

CCB Magazine:Your processes turn faeces into humus. Can't nutrients also be recycled from urine? 

Jolanthe Stelzer:Yes, it can. Even more nitrogen can be recovered from urine than from feces. We are already in the process of implementing a urine treatment plant. We already need part of the urine to enrich our humus fertilizer with nitrogen. 

Quality humus from human feces contains important nutrients such as phosphorus or nitrogen that can be used for agriculture. Up to 25 percent of the nutrients for fertilizers could be recovered from our excreta

CCB Magazine:What is actually so bad about burning feces?

Jolanthe Stelzer:Because important nutrients such as phosphorus or nitrogen are destroyed, which can be used for agriculture. Today, nitrogen and other fertilizers are mined or produced artificially at great technical and energy expense. This consumes two percent of global energy consumption. The operation of wastewater treatment plants also accounts for another three percent. That makes a total of five percent of global energy consumption. But a significant proportion of the fertilizers, at least 25 percent, could be recovered from our excreta. This would require much less energy and at the same time build up humus.

CCB Magazine:But does agriculture have any need at all for more humus? Farms already have far too much manure and don't know what to do with it.

Jolanthe Stelzer:Here, a distinction must be made between stable and unstable nitrogen compounds. Nitrogen contained in liquid manure, for example, can only be partially absorbed by plants, and the rest seeps into our groundwater in the form of nitrate and ammonia. That's bad. Our quality humus, however, consists of stable nitrogen compounds that can be processed by plants.

CCB Magazine:Ok. But then why not just make quality humus from the manure? Why from human feces?

Jolanthe Stelzer:Of course, animal excrements should also be treated before they are spread on the field. Sometimes to remove the drug residues - which are even higher in the animals. But also, for example, to stabilize unstable nitrogen compounds.

CCB Magazine:Finally, sustainability always has something to do with energy consumption. Have you extrapolated the energy consumption of your pilot plant for the use of an entire district?

Jolanthe Stelzer:Such figures are currently being calculated within the zirkulierBAR project. As soon as we have them, we will publish them.

CCB Magazine:Finally: What is your vision? What will the sanitary system of the future look like?

Jolanthe Stelzer:Our big vision is to close the human nutrient cycle - and to give today's generation a long lever in all the hopelessness between climate change etc.. A perspective: Out of powerlessness. As our proverb says: After us the humus!  

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