Thermal treatment of poultry litter: Part I. Characterization by immediate analysis and gravimetric yield

Abstract

ABSTRACT Producing biochar from poultry litter through slow pyrolysis is a farm-based, value added approach to recycle organic residues. Experiments were conducted to examine how heat treatments affected the final composition of carbonized and pyrolyzed material in relation to immediate analysis and gravimetric yield to assess agronomic performance value. These processes were carried out in porcelain containers containing samples of poultry litter and placed in a muffle furnace. The treatments corresponded to three temperatures: samples carbonized at 250 °C (CPL) and pyrolyzed at 350 and 450 °C (PPL). Samples were analyzed in relation to the volatile content, fixed carbon, ash, moisture, pH, electrical conductivity (EC), and zero charge point (ZCP). The PPL350 and PPL450 biochars had the highest ash contents and the lowest fixed carbon, moisture and gravimetric yields. The increase in temperatures used in the process resulted in higher pH and electrical conductivity values. In addition, the ZCP value, with the exception of CPL250, showed the presence of negative charges on the surface of the biochars.