The present invention relates to a method and an installation for dephosphorizing manure and/or biomass. The method of the present invention for processing of manure and/or biomass comprises the steps of : a) fermenting the manure and/or biomass in a first reactor to obtain acidified manure and/or acidified biomass having a pH of below 6, preferably below pH 5.5, preferably below pH 5, b) separating the acidified manure and/or biomass into a liquid fraction and a solid fraction, and c) adding the liquid fraction to a second reactor, which second reactor comprises fermenting liquid fraction having a pH of between 6.5 to 8.5, preferably 7.0 to 8.0, and fermenting the thus obtained mixture in the second reactor.
