title: Dairy manure resource recovery utilizing two-stage anaerobic digestion - Implications of solids fractionation.
abstract: 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.
authors.affiliation: Mountain Waterworks, Boise, ID, USA.
authors.forename: Edmond J
authors.initials: EJ
authors.lastname: Stowe
authors.affiliation: Department of Civil Engineering, University of Idaho, Moscow, ID 83844-1022, USA. Electronic address: ecoats@uidaho.edu.
authors.forename: Erik R
authors.initials: ER
authors.lastname: Coats
authors.affiliation: Department of Civil Engineering, University of Idaho, Moscow, ID 83844-1022, USA.
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Brinkman
mesh_terms: D000693:Anaerobiosis / Q000502:physiology*; D019149:Bioreactors; D005591:Chemical Fractionation; D003612:Dairying; D005285:Fermentation; D008372:Manure / Q000382:microbiology*; D008697:Methane / Q000096:biosynthesis*; D018505:Waste Management / Q000379:methods*
chemical_list: D008372:Manure; D008697:Methane
keywords: Anaerobic digestion; Dairy manure; Hydrogenotrophic/acetoclastic methanogens; Quantitative polymerase chain reaction (qPCR); Volatile fatty acids (VFAs)