Application of hydrothermal processes to biomass and organic wastewaters to produce sustainable energy

Abstract Two main hydrothermal processes are dealt with in this chapter: (1) hydrothermal liquefaction, that is, a combination of thermal depolymerization and a recombination process under moderate temperature ( 374°C and 220 bar), since it is a highly exothermal process that releases a huge amount of heat and generates clean effluents. Both processes are under study to manage their scaling up as alternatives to other conventional processes (pyrolysis, incineration, biological treatments, etc.) for the treatment of different materials: cellulose, agrifood wastes, surfactants, and others. Hydrothermal technologies require rather short residence times (no more than a few minutes in any case) and can be applied to the production of both sustainable energy and valuable chemicals. Based on the studies that can be found in the literature, we intend to present some of the key points of these promising technologies and also its development status worldwide.