Pyrolysis of human feces: Gas yield analysis and kinetic modeling.

ABSTRACT: Pyrolysis of human feces renders the waste free of pathogens and is a potential method of treating fecal sludge waste collected from non-sewered systems. Slow pyrolysis experiments were conducted on human feces and the char yield and gas evolution quantified at 1-10 °C/min heating rates. Char yield ranged from 35.1 to 35.8% (dry mass basis), while the gas yield ranged from 17.2 to 29.6% (dry mass basis). The pyrolysis gases detected were CO, CO₂, CH₄, C₂H₆, and H₂. These non-condensable gases contained a higher heating value (HHV) ranging from 7.2 to 22.8 MJ/Nm³. Kinetic analysis was done by a pyrolysis reaction model free method (Isoconversional) as well as a DAEM (Distributed Activated Energy Model) method that assumes many irreversible first order reactions. Both yielded very close values for activation energy ranging from 141 kJ/mol to 409 kJ/mol, with half of the biomass conversion happening at 241.5 ± 2.9 kJ/mol. The findings of the research provide useful technical information that can guide the design of a pyrolysis system to treat fecal waste. Social acceptance and scale-up issues need to be addressed through further research.

SUBMITTER: Yacob TW 

PROVIDER: S-EPMC6202436 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature