Low-power energy harvester from constructed wetland-microbial fuel cells for initiating a self-sustainable treatment process

Abstract

This is the first study that demonstrates developing a Power Management System (PMS) for initiating a self-automated Constructed wetlands (CW)-microbial fuel cell (MFC). The developed PMS helps by harvesting and storing low power generated from CW-MFC and using it to operate an air-pump used as a part of treatment processes. The great potential for self generating energy harvestors to power electrical instruments makes the CW-MFC technology a sustainable candidate for many applications. In this paper, two laboratory-scale CW-MFC were used for this purpose, the cathode of one CW-MFC (R1) intermittently aerated (IA) with the self-automated air-pump, and the performance compared with the second CW-MFC (R2). An energy harvesting system was configured specifically optimised to suit the low energy output from the CW-MFC. The maximum power generated by R1 and R2 CW-MFC was 54.6 µW and 41.2 µW, respectively, which increased up to 90 µW after IA. The pollutant treatment performance of R1 with IA increased significantly from R1 without aeration and R2 microcosms. The ammonium (NH4+) removal in R1_IA was 10% higher than R1 without aeration and 12% higher than in R2. With the IA, dissolved oxygen at the cathode of R1 increased, which influenced redox potential for better electron recovery and reduced the internal resistance. The use of generated energy from the system makes the technology self-sustainable and high performing.