LED algal microbial fuel cell stack balancing conception: Electronic voltage reversal blockage, light feed-starvation cycling, and aeration

Abstract

Stacked algae microbial fuel cells (AMFC) combine the strategic use of light and microbial energy to generate usable electricity. It generates oxygen directly at the electrodes, providing CO2 cycling, algal biomass, and value-added biomolecules. In this work a 12 Liter LED-Algae-Microbial-Fuel-Cell-Stack with maximum power tracking was investigated for voltage balancing and reversal resolution, enabling up to 1200 mV stable stack voltage under closed circuit conditions. The experiment was run in a municipal wastewater treatment plant for 152 days. A new type of data control computer device was used to block voltage reversals and maintaining power with unit resistances between 42 and 99 Ohm. It also allowed the detection of previously unreported light starvation effects in 16 process variants with voltage drops ranging from 14 to 240 mV switching off lights. Algae generated an oxygen concentration of 1.9–3.7 mg/L during power generation. Extending all light-on conditions significantly reduced the voltage reversal frequency. All light-on in combination with assisted oxygenation using 0.25 L/min air bubbling per unit resolved voltage reversals and balanced the AMFC-Stack.The results obtained are relevant to the study of stacked bioelectric systems that use low substrate concentrations and yet aim to generate stable power and minimize voltage reversals.