Characterization of human manure-derived biochar and energy-balance analysis of slow pyrolysis process

• Thermal and physicochemical characterization of human manure were analyzed.
• Properties of human manure derived biochar are pertinent to be a soil amendment.
• Temperature range between 500 °C and 600 °C is the optimal condition for producing human manure derived biochar.
• When the moisture of human manure is lower than 57%, the pyrolysis system could get net energy output.

Biochars have received increasing attention in recent years because of their soil improvement potential, contaminant immobilization properties, and ability to function as carbon sinks. This study adopted a pyrolytic process to prepare a series of biochars from dried human manure at varying temperatures. The thermal analysis of human manure and physicochemical properties of the resulting biochars illustrated that human manure can be a favorable feedstock for biochar production. In particular, the porous texture and nutrient-rich properties of biochars produced from human manure and may significantly enhance soil fertility when used as used soil additives. A temperature range of 500–600 °C was optimal for human manure biochar production. Significantly, when the moisture content of the feedstock is lower than 57%, the system could not only harvest manure-derived biochar but also have a net energy output, which can be provide heat source for nearby users.