Enhancement of Biogas Production by Co-Digestion of Maize Silage with Common Goldenrod Rich in Biologically Active Compounds

Abstract

This paper analyses the suitability of common goldenrod plants as mono- and co-substrates for biogas production. Furthermore, the role of bioactive compounds included in the biomass of this plant species was investigated. The results showed that the common goldenrod species produced lower biogas and methane yields than maize silage. However, the methane fermentation of their mixture resulted in approximately 9.5% higher biogas yield and 16.6% higher methane yield compared to the theoretical yields estimated based on two mono-digestions. A statistically significant increase in biogas production efficiency resulted from more favorable C/N ratio and the influence of bioactive compounds contained in common goldenrod. The addition of goldenrod crude extract caused an approximately 30% increase in the biogas yield of maize silage. This effect may be associated with a positive impact of biologically active substances on microorganisms or with a decrease in redox potential of the fermenting mass.