RESUMO
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 5-9â¯mg/gVS (99.7%, 40-60â¯nm). The biogas yield increased from 132 (control) to 310â¯mL/gVS with 9â¯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 9â¯mg/gVS. The maximum VS reduction was 19.6%. The highest INT-ETS activity (20.1-37.1⯵gINTred/gVS·h) corresponding to the maximum values of sCOD was reached within the first days. NZVI decreased the ORP to -300â¯mV and increased the VFA's concentration (+2000â¯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.
Assuntos
Nanopartículas Metálicas , Esgotos , Anaerobiose , Biocombustíveis/análise , Ácidos Graxos Voláteis/metabolismo , Ferro/química , Metano/biossíntese , Esgotos/químicaRESUMO
In this work, the effect of coupling ultrasonic pretreatment with dosing of zero-valent iron nanoparticles (nanoferrosonication, "NFS") to improve the anaerobic digestion of sewage sludge was studied. Biochemical methane potential tests were conducted at 15,000 and 25,000â¯kJ/kgTS and their combinations with 2 and 7 mgFe0/gVS. The biogas yield increased from 106 (control) to 143 (25,000â¯kJ/kgTS) and 308â¯mL/gVS with NFS (7 mgFe0/gVSâ¯+â¯15,000â¯kJ/kgTS). The methane content increased from 55.6 to 66%, and the maximum VS removal was 11.5% at 7 mgFe0/gVSâ¯+â¯15,000â¯kJ/kgTS. The results demonstrated that NFS was effective in intensifying the process.