The perfect cycle
Recovered paper is recycled six times before it becomes cellulose insulation. And cellulose insulation can be blown-in up to three times. Yet even then the cellulose is far from worthless. In fact, it may still be extremely useful — as a fertiliser for agriculture. Project leader Prof. Dr. med. Konrad Steiner on a pioneering recycling scheme that completes the cycle for the raw material, wood.
It all started with a specialist magazine article about boric acid. Although boric acid is actually a “substance of very high concern”, the old saying by Paracelsus definitely applies: “The dose makes the poison”. With the correct dosage, boric acid is actually extremely useful — in organic farming, for example, because it is needed by many agricultural crops.
As it happens, boric acid is also used as a natural fire retardant — as part of Isocell's cellulose insulation. Our idea was perfectly logical. We wanted to experiment to see if something useful might arise from this coincidence.
We performed our first experiment using an oven made from food tins that was based on a YouTube tutorial. We transformed old cellulose insulation into coal and sent it to Seibersdorf for analysis. And lo and behold, the results really amazed us. We then started a project with the HBLA Ursprung college, where I work as a teacher.
We recycled old cellulose insulation by carbonising it in a pyrolysis furnace in a toxin-free process and using the waste heat. Incidentally, this took place at the company Sonnenerde in Burgenland because, at that time, they had the only approved professional pyrolysis furnace in Austria. The Austrian Agency for Health and Food Safety Ltd. (AGES) subsequently examined our product for all kinds of toxic substances, such as heavy metals, PAHs or dioxins.
The results were significantly below all legal limits. Incidentally, we are deliberately referring to “products” here rather than fertilisers, because a product can only be called a fertiliser once it has actually been approved for use as such.
We have now been researching and experimenting for two years. Two field trials have been completed; four more are currently underway. Among other things, we have found that corn and rapeseed benefit from our product and it actually increases their protein and fat content. In addition, our first harvest of silage corn saw a seven-per-cent increase in the total yield. It remains unclear why the plants also contained more manganese, as the manganese does not come from the boron coal. However, perhaps boron stimulates the metabolic processes involving manganese, which is a really exciting substance. It has a direct influence on photosynthesis, is involved in the formation of chloroplasts and affects cell elongation. Another of our product’s effects is even more exciting. Our processed cellulose acts like activated carbon and therefore absorbs the odour of manure — up to three quarters of the odour even, as was recognised in a pre-trial at the Wels Campus of the FH Upper Austria University of Applied Sciences (FH Wels).
What we are missing now is the legal framework. Although the Ministry of Agriculture has granted us permission to conduct further field trials with comparatively few hurdles due to the sustainable nature of our project, not officially fertiliser, it is actually classified as waste. And waste cannot be spread on a field!
This is why we need to be able to confirm our experiments and achieve significant repetitions as part of a major research project — and use this scientific basis to obtain approval for our product.
That would be truly ground-breaking. As an expert in resource management and sustainability, I have been involved in the recycling economy and cascade utilisation for some time. Recycling economy means that 100% of the raw material used in the production of a product is returned to the production process at the end of the product's life cycle. Cascade utilisation means that a raw material is used across multiple levels.
In any case, Isocell's cellulose insulation is already a very sustainable product. By the time conventional recovered paper is processed into cellulose insulation, it has already been used six times — and the resulting insulation material is then used up to three times. If we can then process the old insulation that is due for recycling into a fertiliser, this would represent the maximum cascade utilisation of the original raw material, wood. We would thus complete the cycle — and would even end up with a negative carbon footprint, which is de facto the most positive thing you can aim for.