Effect of trace elements on biogas production: Maize silage

In the last decade, the energy requirement in the world has been increasing drastically. Turkey has been the second country in respect of natural gas and electricity requirement growth after China. The growing energy demand has resulted in dependency on energy imports in Turkey. In order to decrease the energy import, alternative energy sources should be developed. Biogas is a type of renewable energy that is generated by using organic matter like food waste, animal waste and energy crops. Biomass capacity is very high in Turkey, and biogas, as an alternative energy source, has a very grand potential to contribute to meet the energy demand in Turkey. The purpose of this experimental work was to analyze the effect of trace elements on biogas generation from maize silage as substrate. Co, Ni and Mo were selected as trace elements, and these elements were added to the reactors separately or in combination at varied doses. The biogas volume, biogas composition, biogas yield and methane yield were monitored in order to investigate the impact of trace element supplementation. Ni and Co were put to the reactors at a rate of 0.1 mg/L and 0.5 mg/L, respectively. The concentration to be added to the reactors for Mo were selected as 0.05 mg/L and 0.25 mg/L. As a result of the experiments, the trace element addition by Ni, Co and Mo increased the biogas volume, biogas composition, biogas yields and methane yields for anaerobic digestion of maize silage.