Two-Stage Process for Energy Valorization of Cheese Whey through Bio-Electrochemical Hydrogen Production Coupled with Microbial Fuel Cell

Abstract

The present work investigates a two-stage process scheme for cheese whey valorization through energy recovery in different forms by means of bio-electrochemical systems. The first stage consisted of an integrated bio-electrochemical process for H2 and electricity production. This combined dark fermentation with an electrochemical system with the aim of overcoming the typical thermodynamic/biochemical limitations of fermentation and enhancing H2 recovery. The second treatment stage involved a single-chamber microbial fuel cell, featuring an innovative configuration consisting of four air cathodes with fly ash as the oxygen reduction catalyst. The bio-electrochemical process performed in the first stage achieved promising results, displaying a three-times higher H2 production yield compared to conventional dark fermentation. In addition, the experiments using the MFC in the second stage were found to successfully exploit the effluent from the first stage, with COD removal yields of 86% ± 8% and energy recovery with a maximum current output of 1.6 mA and a maximum power density of 1.2 W/m3.

Electrochemical Characteristics of Microbial Fuel Cells Operating with Various Food Industry Wastewaters

“…As in the case of CW, a direct comparison with the results of MFC3 and MFC4 is difficult due to the different geometry of the anode electrodes. Moreover, Cercado-Quezada et al [44] used fermented apple juice in a dual-chamber MFC equipped with a 2D graphite felt anodic electrode and found a P max of 44 mW m −2 , while in the study of Zonfa et al [36], a P max of 1.2 W m −3 was obtained when a single-chamber four-air-cathode MFC, was used to produce electricity from the effluent of an hydrogenogenic electro-fermentative reactor using CW. However, both systems are different regarding geometry and thus a direct comparison is difficult to perform.…”

“…While there are studies dealing with the use of CW [8,17,25], or effluents from a dark fermentative hydrogen production reactor fed with cheese whey [17,36] in MFCs, there is a lack of comparative studies working in parallel with different food waste streams, such as the confectionery industry wastewater to correlate their individual characteristics with MFC efficiencies. In the present study, a thorough electrochemical characterization of the MFC systems was performed using electrochemical impedance spectroscopy (EIS) measurements at the beginning and the end of the first operating cycle, at open-circuit potential (OCP) and closed-circuit potential, and the electrochemical characteristics (ohmic and polarization resistance, R ohm and R p , respectively) were determined and correlated, with the specific properties of the individual wastewater type.…”

Architecture Optimization of a Single-Chamber Air-Cathode MFC by Increasing the Number of Cathode Electrodes

“…Creating power management systems allows the voltage output of the MFCs to be matched with the required voltage of a small device such as a sensor or LED light [14]. MFCs have also been used in combination with other processes, such as anaerobic digestion [15,16] or dark fermentation [17,18] in order to maximize energy recovery through wastewater treatment. Another application of the MFC technology is the usage as a biosensor, based on glucose oxidation (catalytic biosensor), offering both sensor capabilities and power supply for biobased devices [19].…”

Anaerobic Digestion of Food Waste: New Research, Challenges and Opportunities

“…On the other hand, different DF issues such as the problems related to substrate characteristics and the low hydrogen yields need to be solved. In the SI, different solutions aimed at improving the DF process have been proposed, including the co-substrate fermentation strategy [9] and the coupling of DF with further processes [10,11].…”

“…Finally, Zonfa et al investigated a two-stage process for cheese whey valorization by integrating DF with an electrochemical system, with the aim of overcoming the thermodynamic/biochemical limitations of fermentation and enhancing hydrogen recovery. The bio-electrochemical process achieved promising results, displaying a three-times higher hydrogen production yield compared to the conventional dark fermentation method [10].…”