Anaerobic co-digestion of grass and forbs – Influence of cattle manure or grass based inoculum. (December 2018)

• Record Type: Journal Article
• Authors: Cong, Wen-Feng; Moset, Veronica; Feng, Lu; Møller, Henrik Bjarne; Eriksen, Jørgen
• Is Part Of: Biomass and bioenergy. Volume 119(2018)
• Page Start: 90
• Page End: 96
• Publication Date: 2018-12
• Subjects: Anaerobic co-digestion -- Biogas -- Forbs -- Inoculum source -- Multi-species grassland; Biomass energy -- Periodicals; Biomass -- Periodicals; Energy-Generating Resources -- Periodicals; Bioénergie -- Périodiques; 333.9539
• DOI: 10.1016/j.biombioe.2018.09.009
• Languages: English
• ISSNs: 0961-9534

Abstract

Abstract: Anaerobic co-digestion of agricultural by-products or wastes with complementarity characteristics is commonly used to enhance methane yield. This study firstly explores the possibility of co-digesting grass and forb species (white clover, chicory and plantain) differing in nutrient composition in enhancing methane yield. This was examined with two inocula (a cattle manure-based inoculum and a grass-based inoculum) in a batch assay. Results showed that co-digesting grass and forbs synergistically enhanced methane yield potential on average by 31 L kg −1 volatile solids (+11%) and reduced lag phase time by 0.8 day in the grass-based inoculum, but not in the cattle manure-based inoculum. Mixtures containing plantain showed more consistent synergistic effect than chicory. Synergistic effects were attributed to more balanced nutrient composition (especially C/N ratio) in grass-forb mixtures. We demonstrate that anaerobic co-digestion of grass and forbs is feasible for enhancing methane yield, which promotes the utilization of multi-species grasslands for bioenergy production. Highlights: Co-digestion of grass and forbs was examined with two inocula in a batch assay. Co-digestion enhanced bio-methane potential in grass-based inoculum. Co-digestion reduced the lag phase time in grass-based inoculum. Synergistic effect was attributed to better nutrient balance in grass-forb mixtures. No effect of co-digestion occurred in cattle manure-based inoculum.