TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Components: The solid urban waste is selected from the organic fraction of solid urban waste deriving from selected collection; prunings deriving from the maintenance of public parks; agribusiness waste products and waste products of large retailers; primary and/or biological sludges produced by urban water treatment plants; or its mixtures. The solid urban waste is wet. The nanodispersed hydrogenation catalyst is selected from sulfides of transition metals such as molybdenum sulfide (MoS2), tungsten sulfide (WS2), or its mixtures, or an oil-soluble precursor of the same. Preferred Process: The solid urban waste is treated by subjecting it to a preliminary grinding or sizing process before being subjected to the liquefaction. The oily phase comprising bio-oil is subjected to hydroconversion together with heavy oils of a fossil origin such as heavy crude oils, bitumens deriving from tar sands, distillation residues, heavy residues deriving from thermal treatment processes, oils deriving from coal, oil shales. Hydroconversion is carried out in the presence of a stream of hydrogen or of a stream comprising a mixture of hydrogen/hydrogen sulfide (H2S). Preferred Composition: The solid urban waste has water content higher than or equal to 50 wt.% with respect to the total weight of the solid urban waste; or the solid urban waste has a water content ranging from 55 wt.% to 80 wt.% with respect to the total weight of the solid urban waste. The oily phase comprising bio-oil and the heavy oils of a fossil origin are used in a weight ratio ranging from 0.01 to 50. The hydrogenation catalyst is used in such a quantity that the concentration of transition metal present in the oily phase comprising bio-oil, or in the oily phase comprising bio-oil together with heavy oils of a fossil origin, ranges from 50 wppm to 50000 wppm. Preferred Conditions: Hydroconversion is carried out at a temperature ranging from 350 degrees C to 480 degrees C. It is carried out at a pressure ranging from 100 bar to 200 bar. It is carried out with an average residence time ranging from 2 hours to 8 hours. EXAMPLE - No suitable example given.