Bioresource Technology, Vol.198, 237-245, 2015
Dairy manure resource recovery utilizing two-stage anaerobic digestion -Implications of solids fractionation
Dairy manure management is increasingly becoming an environmental challenge. In this regard, manure anaerobic digestion (AD) can be applied to address environmental concerns; however, dairy manure AD remains economically uncompetitive. Ongoing research is focused on enhanced resource recovery from manure, including maximizing AD methane yield through a novel multi-stage AD configuration. Research presented herein centered on the hypothesis that separately digesting fine and coarse solids from fermented dairy manure would improve methane production; the hypothesis was disproven. While maximum methane concentration was realized on fine solids, combined solids AD yielded enhanced VS destruction. The diverse combined-solids substrate enriched for a more heterogeneous bacterial/archaeal consortium that balanced fermentation and methanogenesis to yield maximum product (methane). However, results suggest that targeted AD of the fat-rich fine solids could be a more optimal approach for processing manure; alternate (non-AD) methods could then be applied to extract value from the fibrous fraction. (C) 2015 Elsevier Ltd. All rights reserved.
Keywords:Anaerobic digestion;Volatile fatty acids (VFAs);Dairy manure;Hydrogenotrophic/acetoclastic methanogens;Quantitative polymerase chain reaction (qPCR)