Impacts of material characteristics on the anaerobic digestion kinetics and biomethane potential of American bourbon and whiskey stillage

Danielle Hockensmith, Czarena Crofcheck, Tyler J. Barzee

Research output: Contribution to journalArticlepeer-review

Abstract

Stillage of American whiskey (e.g., bourbon) manufacturing is an abundant byproduct that is distinguished from fuel ethanol and malt whisky stillage materials by its highly inconsistent nature due to variability in mash bill composition. The impact of stillage physicochemical characteristics on biomethane production through anaerobic digestion was assessed by characterizing American whiskey stillage samples before batch biochemical methane potential tests of whole stillage. A maximum methane yield of 419 Nml CH4/g VS was obtained under food to microbe ratio (F: M) of 0.5 and organic loading rate (OLR) of 10 g VS/L while digester instability was noted under F: M ratios exceeding 0.5 under batch production. Methane production was significantly influenced by the mash bill composition with lowest methane yields obtained with higher rye content (rye whiskey) and highest methane yields obtained with higher corn content (bourbon or corn whiskey). A multiple linear regression model including C, P, N, and Na was able to accurately describe the methane yield (R2 = 0.93). This study provides valuable insights to aid the design of anaerobic digesters generating renewable natural gas from heterogeneous American whiskey stillage.

Original languageEnglish
Article number121975
JournalJournal of Environmental Management
Volume367
DOIs
StatePublished - Sep 2024

Bibliographical note

Publisher Copyright:
© 2024

Funding

This work was supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch-Multistate project under accession number 1018315.The authors extend their gratitude to Jim Nelson for his assistance with biomass characterization, Zachary Byrd and Ashlyn Lippert for their assistance running the biochemical methane potential tests, and the University of Kentucky Martin-Gatton College of Agriculture, Food and Environment Division of Regulatory Services for material characterization. The authors would lastly like to thank the distilleries that graciously supplied stillage samples for this study.

FundersFunder number
National Institute of Food and Agriculture
University of Kentucky Martin-Gatton College of Agriculture, Food and Environment Division of Regulatory Services
U.S. Department of Agriculture1018315
U.S. Department of Agriculture

    Keywords

    • Biochemical methane potential
    • Corn
    • Distillers' spent grains
    • Distillery
    • Mash bill
    • Rye

    ASJC Scopus subject areas

    • Environmental Engineering
    • Waste Management and Disposal
    • Management, Monitoring, Policy and Law

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