Solid fraction, after the separation of manureslurry, is an interesting source of organic matter, which is also easy to transport (smaller volume). Typically, the organic matter and the phosphate accumulate in the solid fraction.
In Flanders, the solid fraction is usually treated by composting, drying or fermentation, after which the end product is mainly sold in France or other markets which require a P-fertilizer. The downside is that large amounts of carbon from Flanders' soil.
?This is why, the use of solid fraction could also be interesting in Flemish agriculture to increase the organic matter content in the soil but the P-content will always be the limiting factor here.