Welcome to the 1st edition of the Circular Agronomics newsletter!

Circular Agronomics works to investigate and test a wide range of measures to improve carbon and nutrient use in the EU.

In this edition, we take a closer look at one of the selected management practices of one of the project’s six case studies.

For more, see our web news or follow us on Twitter at @CircularAgro.

Pig manure valorisation for organic fertiliser and bioenergy production in Catalonia, Spain


Click here for more details.

The process

The production of high-quality fertilisers from by-products at a biogas plant includes:
  • the process of anaerobic co-digestion of pig manure and co-substrates coming from the agri-food sector;
  • efficient solid-liquid separation (centrifuge);
  • and further treatments of the solid and liquid fraction (thermal/solar drying, stripping).
Then, emission monitoring and minimisation strategies are performed.
The process will result in six different, high-value organic fertilisers and products for fertigation whose fertiliser potential will be tested in field crop rotations and horticultural crops, and soil characteristics will be monitored.
This is complemented by an exhaustive monitoring and characterisation to perform mass (C, N, P, K) and energy balance as well as the Life Cycle Analysis of the overall process.

Closing nutrient cycles at the farm level

The application of solar or thermal drying to the combinations of the different fractions generated during the anaerobic treatment of manure (+co-substrates), the solid-liquid separation of the digestate, and the stripping of the liquid fraction will result in the production of high-quality fertilisers.
Avoiding N emissions will be achieved through manure acidification that will be compared with a reference process without emission control. 

Solar dryer

Expected results

1.   Digestate has an average of 8% dry matter which is expected to increase to 20% in the solid fraction after centrifugation and to 80% after the solar drying process. The stripping process is estimated to recover at least 75% of the remains of nitrogen in the liquid fraction. The concentrate of this process will have around 18% of the N.

2.   The agronomic efficiency in terms of nutrient usage will increase by 20 % compared to the current 15-30 % for N and 15-40 % for P in conventional farming, adding up to a total potential avoided P emission of approximately 2 Mt/yr of N and 0.2 Mt/yr.

3.   The inorganic ammonia, responsible for high nitrate leaching, is recovered as mineral nitrogen fertiliser which is transportable or can be applied when plants need N. This procedure will reduce nitrate emissions to receiving waters by 50 % in regions with high nitrogen surplus and by 10-15 % in European average.

4.   Reduction of environmental impacts in terms of GHG emissions will be achieved and will support Europe’s contribution to meeting the Sustainable Development Goals.

Explore the other five project case studies!

Brandenburg, Germany
Testing organic N fertiliser application strategies, studying genotype differences in mechanisms contributing to N efficiency of plants, management of treated residue application & application strategies & the impact of gaseous emissions and manure characteristics.
Lungau, Austria
Closing N-P & P-Cycles at organic dairy farms (feeding strategies, gaseous emissions and manure characteristics – using a respiration chamber).
Emilia-Romagna, Italy
Conservation tillage and cover crops, digestate treatment (microfiltration) with application via drip line fertigation.
Gelderland, the Netherlands
Testing plant diversity impacts on soil P and mitigating GHG emission, investigating the relationship between earthworms and P availability of plant growth, testing fertiliser ability of several novel biosolid amendments.
South Moravia, Czechia
Recovery of carbon-rich compounds from food production for use in improving carbon content of soils.

Want to change how you receive these emails?
You can update your preferences or unsubscribe from this list.