Computerized voltage reversal prevention in second and third year 1000-liter microbial fuel cell

Large-scale microbial fuel cells treat wastewater while generating electricity, saving electricity and preventing air pollution. Long term use is difficult and hardly realized what is done in this work for more than three years. To prolong the time of service significantly a novel electronic control device was developed. It blocked the notorious and growing voltage reversals over time and balanced the 1000 L microbial fuel cell. It prevented voltage reversals in 64 units in a serial/parallel microbial fuel cell stack setup. This electronic voltage regulator worked in conjunction with maximum power point tracking. Both electronic tools individually optimized 16 microbial fuel cell units simultaneously to achieve stack balance and heal defiant units. To understand the applicability of this computational voltage reversal prevention controller, blocking experiments were performed with variable thresholds set at: +50, +25, 0, −25, −50 mV. The two best blocking thresholds were 50 mV and zero volts. The electronic balancing tool even revived the end-of-life 1000-L microbial fuel cell stack by resolving voltage reversals in the third year of constant operation. The voltage reversal blocker allowed to generate 1.7 to 2.7 times more power than without electronic control. The voltage balancing technique developed is expected to be useful for larger multi-unit microbial fuel cell stacks.