Patent ID: 10836666

Abstract:
There is provided a method of treatment of sludge, such as municipal or industrial sludge from a wastewater treatment plant, comprising the steps of: —preheating an incoming sludge with at least one steam fraction, preferably by direct steam injection, to obtain a preheated sludge; —further heating the preheated sludge with a high-temperature steam fraction, preferably by direct steam injection, to obtain a heated sludge; —hydrothermal carbonization (HTC) of the heated sludge to obtain a HTC-treated sludge; —separating a particle-lean fraction from the HTC-treated sludge; —wet oxidation of the particle-lean fraction to obtain a heated particle-lean fraction; —subjecting the heated particle-lean fraction to a first flashing to obtain the high-temperature steam fraction used in the further heating step; —separating a particle-rich fraction from the HTC-treated sludge; —subjecting the particle-rich fraction to flashing to obtain at least one steam fraction that is used in the preheating step and a cooled particle-rich fraction.