The Effect of Different Zero-Valent Iron Sources on Biogas Production from Waste Sludge Anaerobic Digestion

Anaerobic sludge digestion is still one of the most widely sustainable applications which are used for sludge reduction and energy production. In the present study, the effect of different Zero-Valent Iron (ZVI) sources on enhancing biogas production from anaerobic sludge digestion was evaluated. Three different ZVI sources were examined, namely, ZVI powder, ZVI non-rusty scrap, and ZVI rusty scrap. The results showed that with increasing ZVI powder concentrations from 0 g/l (Control) to 15g/l, CH4 production increased from 1.27 M CH4/gVSS ( for the control) to 2.3 M CH4/gVSS (i.e. 82% increase). While with using 15g/l ZVI scrap (either non-rusty or rusty), CH4 production increased up to 2.45 and 2.7 M CH4/gVSS respectively), which Indicates the possibility of using other cheap ZVI alternatives such as Iron Scrap. The results have confirmed, by using methyl fluoride (CH3F), that supplying anaerobic digestion process with ZVI stimulates the activity of hydrogenotrophic methanogens rather than acetolastic methanogens.