Liquid digestate recycled utilization in anaerobic digestion of pig manure: Effect on methane production, system stability and heavy metal mobilization

Ping Ni, Tao Lyu, Hao Sun, Renjie Dong and Shubiao Wu

Energy, 2017, vol. 141, issue C, 1695-1704

Abstract: The effect of recycled utilization of liquid digestate on methane production and system stability of anaerobic digestion of pig manure were investigated. Two continuous stirred tank reactors were operated for 230 days with varying organic loading rates (OLRs, from 1.5 to 6 g VS L−1 d−1); one reactor was implemented with liquid digestate recirculation and the other was set as the control without recirculation. The present study contributed to prove that digestates recirculation operation could improve the bioenergy production in the anaerobic digestion of pig manure under the OLRs below 5 g VS L−1 d−1. The inhibition of methane production was found under an OLR of 6 VS L−1 d−1, which was caused by significantly increased viscosity from 30 to 1000 mPa s and decreased mass transfer characteristics. The previously reported negative effects of accumulated ammonia and VFA on anaerobic digestion under digestate recirculation were not found. However, the heavy metals Pb, Mn, Cu and Zn accumulated in both liquid and solid fractions of the generated digestate in the digestate recycled reactor. Moreover, the stable carbon isotope analysis of δ13CCO2 and δ13CCH4 in produced the biogas indicate different methanogenic pathways between the anaerobic reactors with and without digestate recirculation.

Keywords: Biogas; Process stability; Recirculation; Swine manure; Stable isotope (search for similar items in EconPapers)
Date: 2017
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (5)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544217319655
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:141:y:2017:i:c:p:1695-1704

DOI: 10.1016/j.energy.2017.11.107

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().