Title:
Comparison of the Physicochemical Properties of Biochar Produced by Sewage Sludge Pyrolysis in a Rotary Kiln and in a Fluidized Bed Reactor
Author(s):
Mendoza-Geney, L., Sanchez Ramirez, F., Pardo Martinez, A., Gómez Mejía, A., Rincón Prat, S.
Document(s):
Paper
Slide presentation
Abstract:
Sewage sludge (SS) produced at the Salitre WWTP in Bogotá represents a major environmental challenge for the Colombian capital due to the large quantities produced and their use or direct disposal limitations. Thermochemical treatments are emerging as a sustainable alternative for treating these hazardous materials since they convert SS into value-added materials or energy sources. This study compares the properties of SS-derived biochar obtained from a pilot-scale rotary kiln and a fluidized bed reactor. Under comparable temperatures, the fluidized bed reactor achieved greater SS decomposition, resulting in lower fixed carbon and volatile matter in the biochar. The solid product retained key agricultural nutrients. Phosphorus retention was higher in the rotary kiln (~90%) than in the fluidized bed (75–80%), while iron, potassium, and calcium showed similar retention across both systems. Sulfur was largely volatilized, with only ~20% of its original content remaining in the solid. Among the heavy metals, chromium exhibited the highest reactivity. Both technologies are suitable for SS thermochemical treatment; however, differences in heat and mass transfer conditions can influence the extent of nutrient retention. These factors should be considered when selecting or optimizing the process for specific recovery goals or end-use applications.
Keywords:
pyrolysis, rotary kiln, sewage sludge, fluidized bed, biochar
Topic:
Biomass Conversion to Biomaterials and Chemicals
Subtopic:
Processes for biomaterials and bio-based chemicals
Event:
33rd European Biomass Conference and Exhibition
Session:
6AO.3.3
Pages:
1066 - 1069
ISBN:
978-88-89407-25-7
Paper DOI:
10.5071/33rdEUBCE2025-6AO.3.3
Price:
FREE
