Comprehensive utilization of slurry through the combined use of microbial fuel cells, hydrogen fuel cells, and microalgae technology (CARE)

Livestock farms is of great economic activity in Spain and in Europe. A high demand for meat contributes to the intensification of livestock farming. In large-scale breeding farms the formation of large quantities of slurry is produced. Slurry is a heterogeneous mixture of solid and liquid animal excrement (approximately 40 % faeces and 60 % urine), uneaten feed particles and water used for hygiene and cleaning purposes. The slurry microflora includes bacteria, fungi, viruses and gastrointestinal parasites, as far as pathogenic microorganisms. Although slurry could be a natural fertilizer, this use poses a risk of soil contamination with biogenic elements and pathogenic microorganisms that can penetrate the groundwater and surface waters threating the health of humans and animals. In addition, nutrient elements, especially nitrogen and phosphorus, which reach water courses and reservoirs contribute to their eutrophication.​

In this context, this project proposes the development of a new and disruptive process to mitigate the problems generated by the intensive production of slurry (see Figure 1). The proposed process is based on the use on the combination of microbial fuel cell, microalgae technology, hydrogen fuel cell, and ionic liquid membrane technology. Specifically, the intensive process could (i) reduce the organic matter present in the slurry, (ii) produce biogas, (iii) biohydrogen (iv) bioenergy and (v) exploit the organic nitrogen compounds and phosphates present in the slurry as biofertilizers and bioestimulants through microalgae technology.​

This work was supported by project PID2024-162882OB-I00, funded by MICIU/AEI (Grant No. 10.13039/501100011033) and co-funded by the European Regional Development Fund (ERDF/FEDER), European Union.