Hydrothermal carbonization of off-specification compost: A byproduct of the organic municipal solid waste treatment

International audienceh i g h l i g h t s HTC of off-specification compost at 180, 220, 250 °C and 1, 3, 8 h reaction time RT. The increase in hydrochar HHV with respect to raw feedstock from 7% to 61%. Hydrochar elemental composition similar to that of peat and lignite for T = 250 °C. Hydrochar thermal stability greatly increased at T = 250 °C and at T = 220 °C when RT = 8 h. HTC results were highly dependent on T, while the effect of RT was much lower. a b s t r a c t The possibility to apply the hydrothermal carbonization (HTC) process to off-specification compost (EWC 19.05.03) at present landfilled was investigated in this work. The aim was to produce a carbonaceous solid fuel for energy valorization, with the perspective of using HTC as a complementary technology to common organic waste treatments. Thus, samples of EWC 19.05.03 produced by a composting plant were processed through HTC in a batch reactor. Analytical activities allowed to characterize the HTC products and their yields. The hydrochar was characterized in terms of heating value, thermal stability and C, H, O, N, S and ash content. The liquid phase was characterized in terms of total organic carbon and mineral content. The composition of the gas phase was measured. Results show that the produced hydrochar has a great potentiality for use as solid fuel