Thermal destruction - non-oxidative

Gasification is conversion at very high temperatures in a partial reducing atmosphere to generate a syngas product

Pyrolysis is the decomposition of organics at temperatures of 300-1300 °C in the absence of oxygen at atmospheric pressure

Hydrothermal processes employ elevated temperatures and pressures in wet conditions and in the absence of oxygen

Hydrothermal carbonisation converts sludge predominantly into a hydrochar solid product at temperatures of 180-300 °C

Hydrothermal liquefaction of sewage sludge takes place at temperatures of 250–400 °C and pressures above 40 bar

Hydrothermal gasification converts sludge to a hydrogen and/or methane-rich gas stream at temperatures up to ~550 °C

Oxidative methods for sludge thermal treatment comprise incineration, wet air oxidation and supercritical water oxidation