The implementation of innovative manure treatment strategies based on resource recovery (N-P-K) offers new opportunities within the framework of circular economy, fertilisation and bioeconomy. The ESPOTFER project seeks to progress towards knowledge transfer and demonstration (validation at TRL-5) of the precipitation of K-struvite (MgKPO₄), a phosphate salt that so far has attracted limited attention. The process will be applied downstream of a nitrification-denitrification (NDN) system treating swine manure, in both the liquid effluent and the waste sludge. The objective is to recover more than 50% of the available K. For the liquid effluent, the addition of Mg and P should be considered, and the use of by-products rich in these elements will be prioritized. The recovered material will be marketable as fertiliser. Moreover, it is also planned to study the precipitation of struvite (MgNH₄PO₄) from the liquid fraction of swine manure before being processed by NDN. Validation tests will be carried out in a pig farm with a NDN system in Osona (Barcelona, Catalonia). The working plan includes the analysis of the economic and environmental sustainability of this technology.