Pilot-scale testing of a leachbed for anaerobic digestion of livestock residues on-farm

Yap, S. D. and Astals, S. and Jensen, P. D. and Batstone, D. J. and Tait, S. (2016) Pilot-scale testing of a leachbed for anaerobic digestion of livestock residues on-farm. Waste Management, 50. pp. 300-308. ISSN 0956-053X

Abstract

A leachbed is a relatively simple anaerobic digester suitable for high-solids residues and on-farm applications. However, performance characteristics and optimal configuration of leachbeds are not well-understood. In this study, two 200 L pilot-scale leachbeds fed with spent straw bedding from pigs/swine (methane potential, B-0 = 195-218 L CH4 kg(-1) VSfed) were used to assess the effects of leachate recirculation mode (trickling vs. flood-and-drain) on the digestion performance. Results showed comparable substrate solubilisation extents (30-45% of total chemical oxygen demand fed) and methane conversion (50% of the B-0) for the trickling and flood-and-drain modes, indicating that digestion performance was insensitive to the mode of leachate flow. However, the flood-and-drain leachbed mobilised more particulates into the leachate than the trickling leachbed, an undesirable outcome, because these particulates were mostly non-biodegradable. Inoculation with solid residues from a previous leachbed (inoculum-tosubstrate ratio of 0.22 on a VS basis) hastened the leachbed start-up, but methane recovery remained at 50% of the B-0 regardless of the leachate recirculation mode. Post-digestion testing indicated that the leachbeds may have been limited by microbial activity/inhibition. The high residual methane potential of leachate from the trickling (residual B-0 = 732 +/- 7 L CH4 kg(-1) VSfed) and flood-and-drain leachbeds (582 (+/-) 8 L CH4 kg(-1) VSfed) indicated an opportunity for further processing of leachate via a separate methanogenic step. Overall, a trickling leachbed appeared to be more favourable than the flood-and drain leachbed for treating spent bedding at farm-scale due to easier operation.


Statistics for USQ ePrint 36092
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions
Faculty/School / Institute/Centre: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Date Deposited: 25 Mar 2019 05:24
Last Modified: 30 May 2019 03:20
Uncontrolled Keywords: anaerobic digestion, leachbed, solid-phase, manure straw, inoculation
Fields of Research : 09 Engineering > 0907 Environmental Engineering > 090703 Environmental Technologies
Identification Number or DOI: 10.1016/j.wasman.2016.02.031
URI: http://eprints.usq.edu.au/id/eprint/36092

Actions (login required)

View Item Archive Repository Staff Only