TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: Treating sewage sludge further comprises generating power from the combusting of the gas, where the power is generated by a gas turbine, steam turbine and/or a heat engine. The suspension comprises particles of the fuel dispersed in the sewage sludge, the particles being characterized by a diameter of 100 mu m or less, or 20 mu m or less. The method as well comprises, prior to the mixing, grinding a solid carbonaceous fuel so as to produce the particles of the fuel; and prior to the mixing, emulsifying a liquid carbonaceous fuel with the sewage sludge so as to produce the particles of the fuel. The gasifying comprises heating the suspension to a temperature of at least 1000 degrees C; and contacting the suspension with hot combustion products which comprise steam. The method also comprises mixing the gas with air prior to the combusting of the gas; and mixing a plasticizer with the fuel and the sewage sludge. Preferred Components: The solid carbonaceous fuel is selected from coal, oil shale and peat. The plasticizer is selected from humic acid and sodium hydroxide. Preferred Parameters: The weight ratio of the fuel to the sewage sludge in the suspension is 0.75:1 to 3:1. The concentration of water in the suspension is at least 25 wt.%. The concentration of the plasticizer in the suspension is 0.1-3%. Preferred System: The system further comprises a sewage sludge supply module; a fuel supply module; and a power generation module configured for generating power from the combusting of the gas in the combustion module. The power generation module comprises a gas turbine and/or a heat engine. The system as well comprises a grinder capable of grinding a solid carbonaceous fuel so as to produce particles of the fuel having a diameter of 100 mu m or less. The system is being adapted for emulsifying a liquid carbonaceous fuel with the sewage sludge so as to produce particles of the fuel having a diameter of 100 mu m or less. The heat source comprises a furnace. Moreover, the system comprises a fuel supply module configured for providing the carbonaceous fuel to the furnace and to the mixer, the furnace being adapted for burning the fuel, where the furnace is configured for supplying combustion products to the gasifier, the combustion products comprising steam. The furnace and the gasifier are configured as a unified module comprising a first zone in which combustion occurs and a second zone in which gasification occurs. The unified module further comprises a third zone in which the combustion of the gas occurs, such that the unified module comprises the furnace, the gasifier and the combustion module. The heat source and the gasifier are configured for heating the suspension in the gasifier to a temperature of at least 1000 degrees C. The system also comprises a compressor configured for supplying oxygen to the combustion module, where the oxygen and the gas are supplied together to the combustion module; and a compressor configured for supplying oxygen to the furnace, where the supplying oxygen comprises supplying compressed air. The system is being adapted for mixing the fuel with the sewage sludge at a weight ratio of 0.75:1-3:1. The system is also being adapted for forming a suspension comprising at least 25 wt.% of water, where the system comprises an atomizer for atomizing the suspension upon entry into the gasifier, where the atomizer comprises a rotating part configured for reducing clogging of the atomizer by particles of the fuel in the suspension. The system is being adapted for mixing a plasticizer with the fuel and the sewage sludge; and for mixing the plasticizer at a concentration of 0.1-3% plasticizer in the suspension. EXAMPLE - No suitable example given.