The invention relates to a method and an arrangement for wastewater treatment, in which at least portions of the sewage sludge contained in the wastewater (0) are subjected to a hydrolysis (8). The hydrolysis (8) is carried out as a thermal hydrolysis. After the hydrolysis step (8), a drying process is (19) carried out. The drying process (19) is a process operating with positive pressure in the steam region. At least parts of the steam resulting from the drying process (19), which operates with positive pressure, are fed (20) to the portions of the sewage sludge in the thermal hydrolysis (8).