Optimization of pyrolysis regime for chicken manure treatment and biochar production

Abstract

Pyrolysis processes and products have yet to be studied fully, and information about chicken-manure (CM) pyrolysis is especially poor. In the present study, biochar obtained from two CM samples at different residence times (1–4 h) and peak temperatures (400–800°C) was investigated. It was found that pH ranged between 6.8–10.3 and 6.6–11.6; EC between 1.8–3.9 and 1.2–11.9 mSm/cm; CEC between 30.0–65.6 and 15.2–146.9 cmol/kg; C, N, P, and K contents between 9.5–25.6% and 15.7–61.2%, 0.7–2.8% and 1.5–6.4%, 1.7–2.7% and 2.5–5.6%, 0.9–2.1% and 1.3–3.6%, respectively; ecotoxicity (LID10) towards aquatic organisms between 1–40 and 1–66; germination indices between 189–353% and 54–265%; and surface areas between 0.1–0.7 and 0.1–0.3 m2/cm3 for the second and first samples of CM, correspondingly. The multiobjective optimization method was used to analyse the results obtained and to choose the pyrolysis regimes that result in the biochar with the highest fertilizing ability.