Effects of Adding Zero Valent Iron on the Anaerobic Digestion of Cow Manure and Lignocellulose

Abstract

Previous studies showed that adding zero valent iron (ZVI) can increase the methane production and degradation rate of organic waste by improving the performance of anaerobic digester. However, our study firstly found that ZVI (37 µm, 10 g/L) inhibited the anaerobic digestion (AD) of cow manure and lignocellulose. ZVI significantly increased the methanogenic rate of cow manure in the first 6 days, but decreased the accumulative methane yield and volatile fatty acids yield by 10.3 and 12%, respectively. The effect of ZVI on AD of liquid biomass separated from cow manure was positive, but the effect on solid biomass was negative. These results indicated that ZVI enhanced the AD of easily biodegradable organics but inhibited the biodegradation of refractory organics (lignocellulose). By analyzing the varying effects of ZVI in diverse anaerobic systems, it was found that the effects were influenced by the characteristics of substrate and inoculum-substrate ratio. This study suggested that only proper ZVI addition can improve the AD process depending on the feeding materials.

Experimental evaluation of the influence of combined particle size pretreatment and Fe3O4 additive on fuel yields of Arachis Hypogea shells

“…The percentage of biogas and methane yields from this research was lesser than these improvements at Fe 3 O 4 alone and combined with particle size reduction. This result negates what was recorded by Men et al (2020) that adding zero-valent iron during anaerobic digestion improved the anaerobic digestion of easily digestible substrates but inhibited the digestion of lignocellulose materials. But, Olatunji et al (2021) have established the effect of nanomaterials on biogas and methane yields.…”

Effect of Combined Particle Size Reduction and Fe3O4 Additives on Biogas and Methane Yields of Arachis hypogea Shells at Mesophilic Temperature

“…When 20 g/L was investigated, a 43.5% increase in methane yield was recorded, which was lower than the ranges recorded here [72]. Men et al [73] experimented with using 10 g/L of zero-valent iron on the anaerobic digestion of lignocellulose materials, and there was a 10.3% decrease in cumulative methane yield. This result is contrary to what was reported when a lower concentration, of 5 and 10 g/mL, was applied during the anaerobic digestion of durum wheat [70].…”

Biostimulation of Anaerobic Digestion Using Iron Oxide Nanoparticles (IONPs) for Increasing Biogas Production from Cattle Manure

“…The increases could have been attributed to the effect of IONPs in syntrophic/cooperative metabolism between electron-donating and electron-accepting microorganisms via direct interspecies electron transfer processes [35,36]. Yu et al [37] studied the effect of zero valent iron (ZVI) on the anaerobic digestion of cow manure. With the addition of 10 g/L ZVI, the cumulative methane and VFA yields decreased by 10.3% and 12%, respectively.…”