Utilization of process liquids with high organic loads in bioelectrochemical systems: Organic degradation rates & current densities

By Ravi, Padma Priya; Oskina, Anastasia; Merkle, Wolfgang; Schilling, Thorben; Hölzle, Ludwig E.; Lemmer, Andreas
Published in Bioresource Technology Reports 2020


This study presents investigations on an enlarged lab-scale bioelectrochemical systems (BES), which are necessary for a technical upscaling of the processes. Maize silage was first hydrolysed and the process liquids hydrolysate and a membrane filtered permeate was subsequently fed to the BES anode chamber. Aim was to investigate the suitability of mixed-culture BES for utilization of process liquids obtained and the substrate influence on the BES performance in terms of organic compounds removal. In all runs, organic acids were completely degraded. Permeate showed 87% and 88% of chemical oxygen demand and total organic carbon removal. Average current density of 4.7 A/m2 was attained for hydrolysate with added acetic acid. Altering the pH value of used process liquids from 5.75 to 7 led to significantly higher current production and degradation rates. Experiments revealed a positive correlation between generated current and difference in redox potential between anode and cathode chamber.

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