AUTHOR=Dai Shixiang , Korth Benjamin , Vogt Carsten , Harnisch Falk 

TITLE=Microbial Electrochemical Oxidation of Anaerobic Digestion Effluent From Treating HTC Process Water

JOURNAL=Frontiers in Chemical Engineering

VOLUME=3

YEAR=2021

URL=https://www.frontiersin.org/journals/chemical-engineering/articles/10.3389/fceng.2021.652445

DOI=10.3389/fceng.2021.652445

ISSN=2673-2718

ABSTRACT=<p>Hydrothermal carbonization (HTC) is a promising technology for chemical and material synthesis. However, HTC produces not only valuable solid coal-materials but also yields process water (PW) with high chemical oxygen demand (COD) that requires extensive treatment. Anaerobic digestion (AD) has been used for initial treatment of HTC-PW, but the AD effluent is still high in COD and particles. Here, we show that microbial electrochemical technologies (MET) can be applied for COD removal from AD effluent of HTC-PW. Bioelectrochemical systems (BES) treating different shares of AD effluent from HTC-PW exhibited similar trends for current production. Thereby, maximum current densities of 0.24 mA cm<sup>−2</sup> and COD removal of 65.4 ± 4.4% were reached (<italic>n</italic> = 3). Microbial community analysis showed that the genus <italic>Geobacter</italic> dominated anode biofilm and liquid phase of all reactors indicating its central role for COD oxidation and current generation.</p>