BETO 2021 Peer Review - Separations in Support of Arresting Anaerobic Digestion

Research output: NRELPresentation


In support of the Bioenergy Technologies Office in converting waste feedstocks to fuels and chemicals, this project develops and demonstrates an advanced system for the production of platform carboxylic acids by Arresting Anaerobic Digestion (AAD) of wet waste feedstocks. The project addresses three technology barriers in developing the bioeconomy; (1) Feedstock availability and cost (2) Selective separation of organic acid species, and (3) First-of-a-kind technology development. This project has developed an advanced AAD system with separations that can operate in high solids environments (> 10 wt.%) and is net positive in energy consumption compared to the energy content of the carboxylic acids. Operating an in situ product recovery (ISPR) system in high solids is required for fermentation produced intermediates beyond ethanol that have volatilities less than water (e.g. carboxylic acids). Carboxylic acids form a versatile platform for the production of renewable diesel fuel, aviation fuel, monomers, and chemicals. A high solids ISPR system expands the feedstocks for AAD, which have been restricted to thin stillage, to solid food waste. Additionally, current AAD technology employs separations that consume >200x the energy content of the produced acids. This project has developed and demonstrated the first AAD technology with ISPR that is net negative in energy value and operates in solids contents >10 wt.% to produce a mixed carboxylic acid product that is carbon negative.
Original languageAmerican English
Number of pages25
StatePublished - 2021

Publication series

NamePresented at the U.S. Department of Energy's Bioenergy Technologies Office (BETO) 2021 Project Peer Review, 8-12, 15-16, and 22-26 March 2021

NREL Publication Number

  • NREL/PR-2800-79461


  • bioeconomy
  • high solids environments
  • waste feedstocks


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