Physicochemical characterization of typical municipal solid wastes for fermentative hydrogen and methane co-production

Highlights: • SEM, FTIR, and XRD showed that FW had more organics and less mineral ash than SS. • H₂ production was used to strengthen acidogenesis to increase CH₄ production rate. • Max CH₄ production rates from FW and SS were 14.8–15.1% higher in two-stage process. • Peak CH₄ production time from FW and SS was 3–6 d earlier in two-stage process. • Energy recovery efficiencies of FW and SS were 3.3–8.7% higher in two-stage process. - Abstract: Physicochemical characterization of typical municipal solid wastes were used for fermentative hydrogen and methane co-production in this study. Scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction analyses were used to characterize the physicochemical properties of food waste (FW) and sewage sludge (SS). FTIR spectra revealed that FW had stronger characteristic peaks of carbohydrates, proteins, and lipids, whereas SS had a higher characteristic peak of mineral compounds. Fermentative hydrogen production was then applied to strengthen acidogenesis to increase methane production rate through anaerobic digestion. The maximum methane production rates from FW and SS (13.31 and 7.18 mL/g-VS/d) in the two-stage process were 14.8% and 15.1% higher than those in the one-stage process, respectively. The peak times of methane production from FW and SS in the two-stage process were 6 and 3 days earlier than those in the one-stage process, respectively. The energy recovery efficiencies of FW and SS in the two-stage process were 3.3–8.7% higher than those in the one-stage process.