Bioelectrochemical enhancement of methane production from exhausted vine shoot fermentation broth by integration of MEC with anaerobic digestion

Abstract

A microbial electrolysis cell integrated in an anaerobic digestion system (MEC-AD) is an efficient configuration to produce methane from an exhausted vine shoot fermentation broth (EVS). The cell worked in a single-chamber two-electrode configuration at an applied potential of 1 V with a feeding ratio of 30/70 (30% EVS to 70% synthetic medium). In addition, an identical cell operated in an open circuit was used as a control reactor. Experimental results showed similar behavior in terms of carbon removal (70–76%), while the specific averaged methane production from cycle 7 was more stable and higher in the connected cell (MECAD) compared with the unpolarized one (OCAD) accounting for 403.7 ± 33.6 L CH4·kg VS−1 and 121.3 ± 49.7 L CH4·kg VS−1, respectively. In addition, electrochemical impedance spectroscopy revealed that the electrical capacitance of the bioanode in MECAD was twice the capacitance shown by OCAD. The bacterial community in both cells was similar but a clear adaptation of Methanosarcina Archaea was exhibited in MECAD, which could explain the increased yields in CH4 production. In summary, the results reported here confirm the advantages of integrating MEC-AD for the treatment of real organic liquid waste instead of traditional AD treatment.

Microbial electrosynthesis for CO2conversion and methane production: Influence of electrode geometry on biofilm development

“…The reactors were bubbled with nitrogen for 30 min at the beginning of each cycle. The amount of nitrogen present in the headspace at the start of each cycle remains inside the reactor and is deducted from the gas recovered at the end of the cycle 30 …”

“…The amount of nitrogen present in the headspace at the start of each cycle remains inside the reactor and is deducted from the gas recovered at the end of the cycle. 30 In the liquid sample, redox (pH-Meter, pH 91; Wissenschaftlich Technische Werkstätten, WTW), pH (pH-Meter BASIC 20+, Crison), dissolved oxygen and conductivity (Hach, HQ40d -two-channel digit multimeter) measurements were monitored following standard methodologies. 31 Total organic carbon (TOC), total inorganic carbon (IC) and total nitrogen (TN) were measured using an analyser (multi N/C 3100, Analytikjena).…”

Thermophilic Anaerobic Digestion: An Advancement towards Enhanced Biogas Production from Lignocellulosic Biomass

“…The presence of microorganisms on an anode yields the electrons from an organic substrate [91]. The reported bioelectrochemical technologies are microbial electrolysis cells (MECs) and microbial fuel cells (MFCs) coupled with a thermophilic anaerobic digester in a single-or double-chambered manner or in series [99][100][101][102]. These technologies have been recently adopted to promote the methane yield enhancement, and to overcome the organic as well as ammonia inhibitions (Figure 2).…”

Use of Carbon-Based Additives in Bio-Electrochemically Assisted Anaerobic Digestion for Cheese Whey Valorisation

“…In recent years, several studies have reported on the benefits of integrating microbial electrochemical technologies, such as microbial electrolysis cells (MEC), with anaerobic digestion to alleviate some of its limitations [12][13][14]. MEC are a type of bio-electrochemical system that can degrade organic matter and, depending on the reactor configuration, generate hydrogen (H 2 ) and/or methane (CH 4 ) (with a small input of electrical energy) [14,15].…”