The EU phosphorus challenge
The H2STEEL Project focuses on the recovery of biocoal and hydrogen from biowaste, aiming for a circular economy and sustainable system. As part of that biocoal recovery, however, other valuable materials are separated. One of them is of particular interest to Europe: phosphorous.
Phosphorus is an indispensable element, needed for life. As such, it is heavily used in fertilisers and other products. But phosphorous is mostly obtained from phosphate rock, a mineral present in only a few places in the world. Because of this, phosphorous is expensive and finite. In fact, phosphorous was included in the European union (EU) list of critical raw materials.
Another reason for this is that a lot of phosphorous is lost. Wastewater releases about 3 million tonnes of phosphorous to the environment every year1. Excessive release of phosphorus and other substances such as nitrogen from wastewater is both an environmental issue and a huge economic loss2. According to W.J. Brownlie et al, 20223, phosphorus losses from land to fresh waters have doubled in the last century and continue to increase.
On top of that, an estimated 80% of phosphorous is lost or wasted during fertiliser use. This happens because of chemical reactions with other elements, becoming unusable for plants, or because it is washed away by rain or irrigation.
And yet, Europe could produce over 2 million tonnes of phosphorous4. It could come from residues such as agricultural waste and sewage sludge. But to make it biologically available for plants and safe from contaminants, extraction of the phosphorous from these waste materials is crucial. The aim would be to produce phosphorous-rich fertilisers. This would help with precision farming practices, which use only enough fertiliser for the specific needs of the land and crops.
H2STEEL and phosphorus recovery
It might seem that H2STEEL’s mission to revolutionise steel manufacture and green hydrogen production is far from the phosphorous challenge of the EU. However, this is not the case.
H2STEEL is working towards biowaste-derived biocoal to serve as a catalyst for green hydrogen production. This biocoal comes from agricultural waste and sludge. The biocoal is separated from these materials using high temperatures. After that, the biocoal also contains high quantities of phosphorous, potassium, calcium and sodium. Most of these elements are not wanted for steel production, as they reduce its quality. For this reason, H2STEEL separates these inorganic elements and removes them from the biocoal.
The result is two products. First, a functional biocoal, usable for green hydrogen production and for steel industries. And second, an inorganic fertilizer, rich in elements needed for plant and crop growth, like phosphorous and nitrogen. More than 97 % of the phosphate present in the original waste is extracted into this fertiliser.
Conclusion
The sustainability of the H2STEEL concept addresses another key challenge of the EU economy, the recovery of critical raw materials. H2STEEL achieves a recovery of more than 97% of phosphorus from sludge and agricultural digestate (the waste used for biocoal production). The result? A high-phosphate salt that can be used as fertilizer, increasing the sustainability and economic viability of the project.
In fact, for each tonne of biocoal produced using H2STEEL technology, about 50-60 kg of P are extracted. Phosphorus is valued in the range of 1.7 €/kg5.
Overall, the H2STEEL project contributes to decarbonise the steel sector and to reduce fossil fuel consumption, but also to recover a critical raw material, phosphorus, leading to a reduction in the extraction and import of phosphate rock from non-EU countries.
References
1 Wastewater – Turning Problem to Solution | UNEP – UN Environment Programme
2 Urban wastewater treatment – European Parliamentary Research Service
3 W.J. Brownlie, M.A. Sutton, K.V. Heal, D.S. Reay, B.M. Spears (eds.), (2022) Our Phosphorus Future. UK Centre for Ecology & Hydrology, Edinburgh. doi: 10.13140/RG.2.2.17834.08645
4 Van Dijk et al. “Phosphorus flows and balances of the European Union Member States”, 2016 http://dx.doi.org/10.1016/j.scitotenv.2015.08.048 updated by van Dijk for P-REX 2016
5 Egle, H. Rechberger, J. Krampe, M. Zessner, Phosphorus recovery from municipal wastewater: An integrated comparative technological, environmental and economic assessment of P recovery technologies, Science of The Total Environment, Volume 571, 2016, Pages 522-542, ISSN 0048-9697. https://doi.org/10.1016/j.scitotenv.2016.07.019
Author: A. Salimbeni, Head of Unit, RE-CORD