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Enhancing the performance and stability of the anaerobic digestion of sewage sludge by zero valent iron nanoparticles dosage
- Lizama, Alfredo Córdova, Figueiras, Cristian Carrera, Pedreguera, Alejandro Zepeda, Ruiz Espinoza, Juan Enrique
- Bioresource technology 2019 v.275 pp. 352-359
- acidification, anaerobic digestion, biogas, iron, methane, nanoparticles, sewage sludge
- This work studied the effects on the anaerobic digestion of sewage sludge by zero valent iron nanoparticles (NZVI) dosage. Biochemical methane potential tests were carried out with 5–9 mg/gVS (99.7%, 40–60 nm). The biogas yield increased from 132 (control) to 310 mL/gVS with 9 mg/gVS. The methane content increased from 63.2% (control) to 77.6% with NZVI, which corresponded to a maximum yield of 238 mLCH4/gVS with 9 mg/gVS. The maximum VS reduction was 19.6%. The highest INT-ETS activity (20.1–37.1 µgINTred/gVS·h) corresponding to the maximum values of sCOD was reached within the first days. NZVI decreased the ORP to −300 mV and increased the VFA’s concentration (+2000 mg/L). The ORP-VFA-pH analysis showed that NZVI promoted the acidogenesis-acetogenesis without acidification. That is, NZVI was effective in intensifying the performance and stability of the process.