Methane production from anaerobic co-digestion of the separated solid fraction of pig manure with dried grass silage

Authors

Sihuang Xie, National University of Ireland, Animal and Grassland Research and Innovation CentreFollow
Guangxue Wu, Tsinghua University
Peadar G. Lawlor, Animal and Grassland Research and Innovation Centre
J P. Frost, Agri-Food And Biosciences Institute
Xinmin Zhan, National University of Ireland

RIS ID

111086

Publication Details

Xie, S., Wu, G., Lawlor, P. G., Frost, J. P. & Zhan, X. (2012). Methane production from anaerobic co-digestion of the separated solid fraction of pig manure with dried grass silage. Bioresource Technology, 104 289-297.

Abstract

Anaerobic co-digestion of the solid fraction of separated pig manure (SPM) with dried grass silage (DGS) was evaluated in three identical continuously stirred tank reactors (CSTRs) at 35 ± 1 °C. The feedstock contained 20% DGS in CSTR1, 30% DGS in CSTR2 and 40% DGS in CSTR3 on a volatile solids (VS) basis. Organic loading rates (OLR) of 1.0, 1.5, 2.0 and 3.0 kg VS/m³/d were studied and it was found that the OLR affected the digester performance more than the DGS proportion in the feedstock. Tripling the OLR increased volumetric methane yields by 88% and decreased specific methane yields by 38%. At the OLR of 3 kg VS/m³/d, post-methane production potentials of digestates ranged from 38% to 41% of total methane production potentials of the feedstock. An energy yield estimation on a 654-sow pig unit showed that 268-371 MWh/a electricity and 383-530 MWh/a heat would be generated.