A feasibility study of agricultural and sewage biomass as biochar, bioenergy and biocomposite feedstock: Production, characterization and potential applications

- PSD biochar was found to have the highest surface, carbon content and lowest ash content.
- PSD biochar is suitable for carbon sequestration, remediation and biocomposite construction.
- Syngas from PSD and PG pyrolysis yielded syngas having highest calorific values (15-16 MJ/dsm).
- BL, PG and SS derived biochars have potential as liming agents due to their high ash content.

In this study, we pyrolysed six waste derived biomass: pine sawdust (PSD), paunch grass (PG), broiler litter (BL), sewage sludge (SS), dewatered pond sludge (DWP), and dissolved air-floatation sludge (DAF) into biochar. Biochars were characterized using scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, Fourier transform infrared spectroscopy, inductively-coupled plasma mass spectrometry, 13C-solid-state nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy to evaluate their feasibility for potential agronomic and environmental applications. Syngas produced during the pyrolysis process was also analyzed to determine the energy values. Results show that PSD biochar has the utmost potential for carbon sequestration and contaminant remediation due to its high surface area, aromaticity and carbon content. Additionally given its low ash content, PSD biochar could also potentially be used as filler in wood plastic biocomposites. Low levels of heavy metals (Cr, Cu, Zn, As, Cd, Hg, and Pb) in all biochars suggest that biochars are also applicable for land application according to the United States Environmental Protection Agency regulation 40 CFR part 503. The composition of syngas evolved during the pyrolysis of feedstocks showed little difference in the calorific values, ranging from 12-16 MJ/dsm with PSD having the maximum calorific value of 16 MJ/dsm.