Mapping thermomechanical pulp sludge (TMPS) biochar characteristics for greenhouse produce safety.

This study evaluates the existence of toxic compounds in thermomechanical pulp sludge (TMPS) derived biochars obtained through a slow pyrolysis process and establishes the criteria for manufacturing benign-quality biochar for safe greenhouse-based food production. Accordingly, nine TMPS biochars generated at different temperatures (450, 500, 550 °C) and residence times (30, 60, 120 min) were investigated. Depending on the production conditions, the polycyclic aromatic hydrocarbons (PAHs) sum varied from 0.