Thermochemical valorisation of waste: Pyrolytic conversion of horse manure

The efficient and sustainable disposal of waste represents one of the major challenges for the human beings in the next future. The thermochemical conversion of livestock manure to biochar has received much interest thanks to its greenhouse gases extenuation and amendment power. In this study, horse manure was processed under pyrolytic condition at different temperatures, heating rate and residence times. In the first phase, a set of preliminary analysis aimed to assess the physical and chemical properties of the horse manure were carried out. Analogously, after the pyrolysis, the biochar was analysed both from the chemical and physical point of view. The results showed that the major impact on biochar yield (average −32%), pH (average + 40%), SSA (average 27.8 m²/g), PAH content, C (average + 37.4%) H (average −53.1%) N (average −15.5%) S (average −65.9%) O (average −37%) content was due to the HHT (highest heating temperature). Residence time (RT) and heating rate (HR) do not display a noticeable trend for most of the parameters. This analysis permitted to assess a range of pyrolysis parameters to treat this kind of biomass: 600°C (HHT), 10 °C/min (HR) and 2h (RT), in order to comply with EBC (European Biochar Certification) standard.