Synergistic of nanoparticles and pretreatment on biogas yield from anaerobic co-digestion of municipal waste and sewage sludge

Abstract

Abstract Municipal solid waste (MSW) and sewage sludge (SS) have a great potential for producing greenhouse gases and environmental pollution, and as such it would be beneficial to treat them and change them into biogas. Yet, a serious challenge is the complex structure of lignocellulose and the difficulty of its bioconversion. A solution to degrade the lignocellulose structure is the use of pretreatments and nanoparticles with proper concentrations. For this purpose, the synergistic effect of 6%NaOH pretreatment with different magnetite nanoparticles (MNP) concentrations was assessed for maximizing the biogas production. In this study, the optimalmixing ratio of MSW and SS co-digestion was determined from our previous studies (MSW:SS: 60:40). Application of the 6%NaOH pretreatment alone increased biogas and methane production by 24.6 and 35.4% respectively, compared to the control. Also, the 6%NaOH pretreatment alone elevated cellulose by 85% while reducing lignin and hemicellulose by 64and 33% respectively. The greatest biogas and methane production was obtained in the reactor of 6%NaOH with MNP concentration 110 ppm, experiencing 86 and 162% increase compared to the control. The greatest reduction in total solids and volatile solids was also obtained in this digestor by 76.6 and 79% respectively compared to the control reactor.