Evaluating the efficiency of a mixed culture biofilm for the treatment of black liquor and molasses in a mediator-less microbial fuel cell

Abstract

A microbial fuel cell (MFC) is an emerging environment-friendly technology to recover the useful energy available in waste by using microorganisms as catalyst. In this study, double chamber mediator-less MFCs separated by proton exchange membrane (PEM; Nafion) were constructed to determine the efficiency of mixed culture in using complex substrates (molasses and black liquor). It was found that activated sludge can serve as efficient source of electricigens for biofilm development on an anode. Power density of 2.425 W/m² was generated from molasses with chemical oxygen demand (COD) removal efficiency of 67% as compared to power density of 3.55 W/m² produced from black liquor along with COD removal efficiency of 78%. Moreover, it was demonstrated that surface area of PEM has a significant effect on power generation. An almost 5- to 8-fold increase in voltage was observed as the size of PEM was increased from 6.5 to 25 cm².

Recent progress in microbial fuel cells using substrates from diverse sources

“…A study was conducted to evaluate the efficiency of a double chamber MFC using complex substrates such as molasses and black liquor [ 35 ]. The study showed the positive effect of activated sludge by increasing the efficiency of electrogenic bacteria.…”

“…Efficiency parameters such as PD max of 2.425 W m −2 and COD removal of 67% were observed with molasses, whereas PD max of 3.55 W m −2 and COD removal of 78% were observed with black liquor. Increasing the surface area of the PEM increased the voltage generated by 5–8 times [ 35 ]. Similarly, a dual-chamber MFCs performance was evaluated using simulated molasses wastewater, with MnO 2 as the cathode catalyst for carbon cloth cathode or carbon felt cathode [ 51 ].…”

“…This review focuses on the recent expansion of MFC technology for treatment and electricity generation from an ever-expanding range of wastewater sources. For example, complex substrates are a mixture of different chemical compounds and often contain microbial communities [ 35 ]. These complex substrates primarily include domestic wastewater from municipal [ 36 , 37 ], kitchen, and food waste [ 38 , 39 ] sources.…”

Sustainable Waste-to-Energy Technologies: Bioelectrochemical Systems

“…Therefore controlling methanogens in MFCs is an important operational parameter to ensure that the substrate is consumed during power production. Full-strength molasses wastewater (130,000mg COD/L) was used in a two-chamber MFC (Ali et al, 2016). The cell achieved 67% COD removal and produced a maximum power density of 242 mW/m 3 .…”

Characterization of the Electric Current Generation Potential of the Pseudomonas aeruginosa Using Glucose, Fructose, and Sucrose in Double Chamber Microbial Fuel Cell

“…Subsequently, an electron is conducted towards cathode in order to directly convert chemical energy into electrical energy achieving wastewater treatment. Protons on the other side are transported to the cathode chamber through a proton conducting material like Nafi on membrane (3) or salt bridge where it combines with the electron and oxygen to form water using diff erent biological or chemical catalysts (4,5).…”