Co-digestion of salix and manure for biogas: importance of clone choice, coppicing frequency and reactor setup

Abstract

Animalmanure represents amajor source of renewable energy that can be converted into biogas
using anaerobic digestion. In order to most efficiently utilize this resource, it can be co-digested with
energy dense, high biomethanation potential feedstocks such as energy crops. However, such feedstocks
typically require pretreatments which are not feasible for small-scale facilities.We investigated the
use of single-stage and the sequential co-digestion of comminuted but otherwise non-pretreated Salix
with animal manure, and further investigated the effects of coppicing frequency and clone choice on
biomethanation potential and the area requirements for a typical Swedish farm-scale anaerobic digester
using Salix and manure as feedstock. In comparison with conventional single-stage digestion, sequential
digestion increased the volumetric and specific methane production by 57% to 577 NmL L􀀀1 d􀀀1 and
192 NmL (g volatile solids (VS))􀀀1, respectively. Biomethanation potential was the highest for the twoyear-
old shoots, although gains in biomass productivity suggest that every-third-year coppicing may
be a better strategy for supplying Salix feedstock for anaerobic digestion. The biomethane production
performance of the sequential digestion of minimally pretreated Salix mirrors that of hydrothermally
pretreated hardwoods and may provide an option where such pretreatments are not feasible.

Keywords

anaerobic digestion; co-digestion; energy crops; manure; Salix

Published in

Energies
2020, volume: 13, number: 15 , article number: 3804

SLU Authors

• Ohlsson, Jonas

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

• Rönnberg Wästljung, Ann-Christin

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

• Nordh, Nils-Erik

  • Department of Crop Production Ecology, Swedish University of Agricultural Sciences
    

• Schnürer, Anna

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

Global goals (SDG)

SDG7 Affordable and clean energy

UKÄ Subject classification

Microbiology
Other Biological Topics
Agricultural Science

Publication identifier

• DOI: https://doi.org/10.3390/en13153804

Permanent link to this page (URI)

https://res.slu.se/id/publ/107061