More than 6,000 hours of development work have gone into the biorefinery planned in Oripää through the RUORI project, funded by the Finnish Ministry of the Environment. The result is a concept that recycles nutrients and reduces nutrient runoff into the Archipelago Sea.
Biogas plants usually focus on waste treatment and gas production. Processing the nutrients in the digestate gets less attention, because handling it, and especially drying it, has been expensive.
RUORI (Getting Nutrient Loading Under Control) started from the other end. The team first talked with livestock farmers in the Archipelago Sea catchment area in southwest Finland to understand their needs, both for how the plant should work with their farms and for its fertiliser products. Project manager Eetu Lankinen of Wega says the aim was to treat digestate as a valuable raw material rather than a problematic by-product. Its nutrients are refined into products that can be used efficiently and transported to where they are needed.
Nutrients where they are needed
About 90% of digestate is water. The concept separates out the water and refines the remaining nutrients into fertiliser products and soil improvers. Drying uses waste heat from the plant’s own processes, which makes it economically viable.
Europe has tens of thousands of biogas plants, but few make digestate refining as central as this one. Lankinen expects interest elsewhere in Europe, especially in regions with heavy livestock production that need more efficient nutrient recycling.
A key point for the Archipelago Sea is that phosphorus is separated from the products returned to nearby pig farms. Fields already rich in phosphorus therefore don’t accumulate more of it, while the other nutrients still go back to them. Lankinen describes the concept as an industrial-scale solution to one of the main causes of nutrient loading in the Archipelago Sea. It is built around farmers’ needs and is also economically viable.
The work has included:
- a survey of about 100 local pig and cattle farmers
- mapping regional feedstocks suitable for biogas production
- developing the technical concept with design partners
- quality and market studies of fertiliser products
- techno-economic feasibility studies
RUORI runs until the end of November 2026, and its results will feed into further planning of the Oripää biorefinery.
Off the Hot Spot list
HELCOM, the intergovernmental body that protects the Baltic Sea marine environment, keeps a list of “Hot Spots”, the region’s most significant pollution sources. Finland has one site left on it: diffuse nutrient loading from agriculture in the Archipelago Sea catchment. Getting it removed is a national goal.
An official assessment published in 2025 found that Finland had met 17 of the 23 criteria for removal. Most of the six outstanding criteria concern manure management, in particular moving manure phosphorus to crop farms or out of the catchment altogether. Lankinen says the biorefinery is designed to help close exactly these gaps, directly reducing nutrient loading in the Archipelago Sea.
The Ministry of the Environment has supported the project with about €380,000 through the AHTI programme for improving the state of waters and the sea.
Contact
Eetu Lankinen
Project Manager, Wega
+358 40 419 6920
