By Henning Lyngsø Foged, Organe Institute, and Christopher Ciantar, FCCS
Since 2016, SYNECO has been systematically engaged in identifying, testing, developing, piloting, and demonstrating solutions to improve manure management and fertilisation practices. The primary objective is to implement practical and cost-effective approaches for recycling nitrogen (N) and phosphorus (P) nutrients from livestock manure into crop production systems, while also returning organic matter—including carbon (C)—to soils to enhance soil fertility.
SYNECO’s concept.
The conclusion is that livestock manure should be anaerobic digested, since digestate is an eminent and homogenous product that is ideal for further processing into bio-based fertilisers.
At the same time, the harvested biogas has a positive impact on the climate footprint of the animal sector and represents a real value. The digestate shall be processed into bio-based fertiliser types, that suits Malta farmers conventional way of fertilisation, avoiding needs for investments in other transport, storage or spreading equipment.
- Ammonia Sulphate Solution (ASS), recovered from the digestate separation liquids, suits current practices of local farmer using fertigation via drip irrigation under plastic covered mulches. ASS is acidic and will have a reducing and healing effect on the high pH of Maltese soils.
- The separation solids are foreseen to be processed into manure pellets or granules after acidification and drying, and they can replace expensive imports of manure pellets as well as local composts that farmers currently use. The acidification means that the NH4–N content is preserved instead of evaporating, and it also means that the P content becomes more plant available. The pH of the product will be below neutral and will thus contribute to reduce the high pH of the local soils.
Up until 2025, one pilot installation was established on a farm for the anaerobic digestion of slurry, as well as for the separation of the digestate and for the processing of the liquid fraction into Ammonia Sulphate Solution.