Abstract: Method and apparatus for processing a watery substance, such as sludge or manure, wherein in a mixer-drier (33) the watery substance to be processed, which may or may not be mechanically partly dewatered (in 31) and/or preheated (in 32), is mixed with zeolites of type A, which adsorb water from the watery substance while releasing adsorption heat which causes an amount of moisture to evaporate, while from the mixer-drier vapor and a mixture of zeolites and dried matter are discharged, whereafter the zeolites are regenerated in an oven (35) through heating, and are returned to the mixer-drier after being separated from dry matter residue formed by the heating, such as ash, and released moisture. Prior to the supply to the oven, at least a part of the dried matter can be extracted by a separation device (34) the mixture formed in the mixer-drier.