Effect of pig manure to grass silage ratio on methane production in batch anaerobic co-digestion of concentrated pig manure and grass silage

Authors

Sihuang Xie, National University of IrelandFollow
Peadar G. Lawlor, Animal and Grassland Research and Innovation Centre
J P. Frost, Agri-Food And Biosciences Institute
Zhenhu Hu, Hefei University of Technology
Xinmin Zhan, National University of Ireland

RIS ID

111083

Publication Details

Xie, S., Lawlor, P. G., Frost, J. P., Hu, Z. & Zhan, X. (2011). Effect of pig manure to grass silage ratio on methane production in batch anaerobic co-digestion of concentrated pig manure and grass silage. Bioresource Technology, 102 5728-5733.

Abstract

Anaerobic co-digestion of concentrated pig manure (PM) with grass silage (GS) at five different PM to GS volatile solid (VS) ratios of 1:0, 3:1, 1:1, 1:3 and 0:1 was evaluated by examining operation stability and methane (CH₄) production potentials. The highest specific CH₄ yields were 304.2 and 302.8 ml CH₄/g VS at PM to GS ratios of 3:1 and 1:1, respectively. The digestion systems failed at the ratio of 0:1. The lag phase lasted 29.5, 28.1, 24.6 and 21.3 days at the ratios of 1:0, 3:1, 1:1 and 1:3, respectively. The daily methane yield was linearly correlated with the acetic acid concentration, indicating methane production was probably associated with acetoclastic methanogenesis. The hydrolysis constant linearly decreased with increasing the fraction of GS in the feedstock. This study recommends applying the PM to GS ratio of 1:1 in practice due to a high specific methane yield and a short lag phase.