Recovering energy and nutrients from livestock manure – the process
The process integrates anaerobic digestion, separation and membrane filtration in several steps:
- Manure transport and storage
Pig manure is delivered from farms and stored before treatment. - Anaerobic digestion (AD)
The manure is processed in a digester, where microorganisms break down organic matter and produce biogas, which can be used as a renewable energy source. - Digestate separation
After digestion, the material is separated into:
- A solid fraction, rich in phosphorus
- A liquid fraction, containing nitrogen and potassium
- Membrane filtration
The liquid fraction is treated using membrane filtration, separating clean water from a nutrient-rich concentrate (NK concentrate). - Evaporation and nutrient recovery
The concentrate is further processed through evaporation to produce:
- Potassium fertiliser
- Ammonia solution
- Water recovery and discharge
The treated water is filtered and checked before being safely released into the environment.
The final products
This process produces three types of fertilisers from pig manure:
- Phosphate fertiliser (P₂O₅) from the solid fraction
- Potassium fertiliser (K₂O) from the liquid fraction
- Ammonia solution (NH₃) as a nitrogen fertiliser
In addition, the process generates biogas, contributing to the energy supply of around 3,000 households.