Experimental results
A critical review on the techno-economic feasibility of nutrients recovery from anaerobic digestate in the agricultural sector
The environmental impacts of fossil-based fertilizers and the depletion of their raw materials have intensified global interest in alternative, sustainable nutrient sources. Agricultural digestate—especially from livestock manure—offers significant potential, with around 180 million tonnes produced annually in the EU containing high levels of nitrogen and phosphorus. This review compares key technologies for recovering these nutrients, highlighting ammonia stripping and struvite precipitation as the most advanced and cost-effective options, achieving recovery rates of 80–90%. Membrane technologies such as ultrafiltration and reverse osmosis show strong recovery performance but face challenges with fouling and higher operating costs. Additional emerging methods, including membrane contactors, ion exchange, evaporation, and electrodialysis, are also discussed in terms of their current development and limitations.
A-critical-review-on-the-techno-economic-feasibility-of-nutrients-recovery-from-anaerobic-dig.pdfNutrient recovery from anaerobic digestate by different combination of pressure driven membranes
Pig Slurry Concentration by Vacuum Evaporation: Influence of Previous Mesophilic Anaerobic Digestion Process
This study looked at removing water from pig slurry by evaporating it under vacuum to reuse the clean water. Researchers tested how different pH levels and whether the slurry was fresh or already digested affected the quality of the condensed water. They found that the amount of ammonia and other substances in the condensate depended strongly on the pH. Anaerobic digestion before evaporation had clear benefits, because it used up smelly and volatile compounds, helping produce cleaner condensed water and reducing pollution.
Pig-Slurry-Concentration-by-Vacuum-Evaporation.pdfVacuum Evaporation of a Liquid Digestate from Anaerobic Digestion: A Techno-economic Assessment
This study examines whether vacuum evaporation (VE) is a cost-effective way for biogas plants to reduce the volume of liquid digestate they must handle. VE can significantly cut transport costs by shrinking the amount of material that needs to be moved, but its advantages depend heavily on each plant’s specific circumstances. It becomes more profitable when transport distances are long, while high electricity feed-in tariffs make it less attractive because the evaporator consumes power that could otherwise be sold. Under typical conditions, VE is economically worthwhile mainly when digestate needs to be transported more than about 20 km. Overall, the study concludes that VE is not suitable for every biogas plant and that careful economic analysis is necessary before investing.
Vacuum-Evaporation-of-a-Liquid-Digestate-from-Anaerobic.pdf