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Water Environment Federation
Water Environment Research
Pyrolysis is a thermal process that converts biosolids into biochar (a soil amendment), py-oil and py-gas, which can be energy sources. The objectives of this research were to determine the product yield of dried biosolids during pyrolysis and the energy requirements of pyrolysis. Bench-scale experiments revealed that temperature increases up to 500 °C substantially decreased the fraction of biochar and increased the fraction of py-oil. Py-gas yield increased above 500 °C. The energy required for pyrolysis was approximately 5-fold less than the energy required to dry biosolids (depending on biosolids moisture content), indicating that, if a utility already uses energy to dry biosolids, then pyrolysis does not require a substantial amount of energy. However, if a utility produces wet biosolids, then implementing pyrolysis may be costly because of the energy required to dry the biosolids. The energy content of py-gas and py-oil was always greater than the energy required for pyrolysis.
McNamara, Patrick J.; Koch, Jon; Liu, Zhongzhe; and Zitomer, Daniel, "Pyrolysis of Dried Wastewater Biosolids Can Be Energy Positive" (2016). Civil and Environmental Engineering Faculty Research and Publications. 139.
Published version. Water Environment Research, Vol. 88, No. 9 (September 2016): 804-810. DOI. © 2016 Water Environment Federation. Used with permission.