Risk Evaluation of Pyrolyzed Biochar from Multiple Wastes

Table 1

Biochar properties and hazards exhibited.

Biochar feedstock	Biochar properties measured (elemental composition)	Hazards exhibited	References
Bamboo	P, EC, H, Corg, Corg/N, Atomic H/Corg, ash, CEC, SA (BET), alkalinity	Cu, Zn	[23]
Municipal sewage sludge	pH, volatile matter, ash, fixed carbon, N, C, H, S, O, Cu, Cr, Zn	Cu, Cr, Zn	[24]
Pitch pine wood char and natural char	Helium solid density, surface area, electrical resistivity, H/C ratio	40 TCPL contaminant PAHs detected	[25]
Wheat straw	pH, SOC, N, bulk density	Increased CH4 and CO2 emission; Decreased N2O emission	[26]
Rice straw	Ash, C, H, N, O, H/C, O/C	Cu, Cd, Pb, Cr, Zn, Ni	[27]
Green waste compost and hardwood	pH, total organic carbon, water-soluble carbon, dissolved organic carbon, water-soluble nitrogen, and concentrations of dissolved total nitrogen	Pb, Zn, As, Cu; Cd, PAH reduced	[28]
Paper mill sludge	pH, volatile matter, ash, fixed carbon, N, C, H, S, O, Cu, Cr, Zn	Cu, Cr, Zn	[24]
Sawdust	Ash, C, H, N, O, H/C, O/C	Cu, Cd, Pb, Cr, Zn, Ni	[27]
Wheat straw	pH, SOC, N, bulk density, surface area, ash content	CH4 enhanced with more application; N2O emission reduced, CO2 unchanged	[29]
Rice straw	P, EC, pH (H2O), C, N, H, Corg, Corg/N, Atomic H/Corg, ash, CEC, SA (BET), alkalinity	Cu, Pb and Zn	[23]
Wheat straw, poplar wood, and spruce wood	Ash content, C, N, H	9 US EPA PAHs identified	[30]
Slaughterhouse sludge	pH, volatile matter, ash, fixed carbon, N, C, H, S, O, Cu, Cr, Zn	Cu, Cr, Zn	[24]