Biochar prepared from human feces (HFBC) as a promoter in biohydrogen production using simulated feces as substrate

Human feces contain a lot of nutrients and organic matter, which can be used in many fields. In this study, biochar (HFBC) was prepared at 300, 500 and 800 °C using human feces as substrate, and the characteristics of HFBC prepared at different pyrolysis temperatures were investigated. It was confirmed that HFBC prepared at 800 ℃ (HFBC-800) had a better pH buffer capacity, more proportion of π-π shake-up satellites, better graphitization degree and higher conductivity, which could promote the efficiency of biohydrogen production of bacteria. Furthermore, the biohydrogen production of Thermoanaerobacterium thermosaccharolyticum M18 using different concentrations of simulated human feces (SHF) was further investigated. The best biohydrogen production was found for 40 wt%-SHF, with 128.54 mmol H₂/L produced in 180 h. The highest biohydrogen production of 148.75 mmol H₂/L was obtained by adding 6 g/L HFBC-800 to the biohydrogen production process. This study provides a feasibility for high-performance hydrogen production from human feces and presents an insight into the resource utilization of human waste.