Feasibility study on the processing of surplus livestock manure into an organic fertilizer by thermal concentration - The case study of Les Plenesses in Wallonia

Manure processing is a promising option to improve the management of livestock manure in regions with high livestock density and nitrate vulnerable water bodies. It is the aim of this paper to provide a feasibility study for the production of an organic fertilizer from livestock manure, including a GIS-based spatial analysis of regional manure availability. The analysis is provided for the case study Les Plenesse in Wallonia, i.e., a system that uses excess heat from a biomass cogeneration plant to process livestock manure into a high-value organic fertilizer. First, the livestock manure potentials and the nutrient demand for forage crops and pastures in Wallonia are estimated. Then the economic aspects of the production of the organic fertilizer are investigated and the manufacturing costs are assessed on this basis. The results for the case study show that only 46% of the cattle manure is needed to meet 50% of the nitrogen demand of forage crops and pastures. In the presented case study, solid cattle manure turns out to be the most promising manure type for organic fertilizer production with manufacturing costs estimated at 54 €/t fertilizer (85% dry mass). The EU-wide applicable approach can help to quantify the eventually required subsidies for manure-processing technologies. This can significantly improve the existing qualitative statements on the costs of manure processing.