Poorly managed livestock waste drives nitrogen and phosphorus losses into waterways, fuelling eutrophication, and EU policy has increasingly pushed for sustainable nutrient management and better recirculation of phosphorus within agricultural systems. Treating animal by-products into nutrient-balanced bio-based products offers a route that addresses both the pollution problem and Europe's dependence on imported inorganic phosphorus fertilisers. A central comparison in the study concerned application rates.

The modelling showed that animal bone char, a phosphorus-rich product made from rendered bones, would need to be applied at 74 to 131 kilograms per hectare per year, a range closely matching the 77 to 107 kilograms per hectare per year typically applied as diammonium phosphate, the most common mineral phosphorus fertiliser. This parity suggests animal bone char could substitute for conventional fertiliser at comparable spreading intensities. From an environmental standpoint, the authors describe animal bone char as an attractive and promising phosphorus fertiliser option for a more sustainable and circular agricultural system, one that would not rely exclusively on imported inorganic phosphorus.

The study is based on data drawn from relevant literature and databases rather than new field trials, so its figures represent modelled estimates of annual phosphorus outputs and application requirements at the scale of the EU-27. The plant-available phosphorus content of each bio-based product was assessed to allow comparison across the different treatment routes, from composting to pyrolysis-based processes producing biochar and bone-derived materials. Despite the promising numbers, the path to market is not straightforward.

The authors note that innovative incentives, techniques and policies are needed to overcome the economic and technical challenges currently affecting the introduction of animal bone char and comparable products. By quantifying how much phosphorus sits in pig slurry, poultry litter and rendering by-products, and by benchmarking bio-based products against diammonium phosphate, the study provides a data-driven baseline for designing the incentives and treatment technologies that a circular phosphorus economy would require.

Subject of Research: Phosphorus recovery and reuse from livestock manure and rendering by-products in the EU-27

Article Title: Untapped potential: phosphorus recovery and reuse options from livestock manure and rendering by-products in the EU-27

Article References: Ekane, N., Nobile, M., Someus, E., Rosemarin, A., & Pugliese, M. (2026). Untapped potential: phosphorus recovery and reuse options from livestock manure and rendering by-products in the EU-27. Frontiers in Sustainable Food Systems, 10, 1926441. https://doi.org/10.3389/fsufs.2026.1926441

Image Credits: AI Generated

DOI: 10.3389/fsufs.2026.1926441

Keywords: phosphorus recovery, animal by-products, pig slurry, poultry manure, animal bone char, bio-based fertilisers, circular agriculture, eutrophication, diammonium phosphate, EU-27, nutrient recycling, struvite