Earthen Pot–Plant Microbial Fuel Cell Powered by Vetiver for Bioelectricity Production and Wastewater Treatment

Abstract

Novel earthen pot–plant microbial fuel cells (PMFCs) are constructed as a wastewater filtering and microelectrical power system. Its performance is investigated at different influent chemical oxygen demand (COD) strengths of 50 mg L−1 (P‐COD50), 250 mg L−1 (P‐COD250), and 500 mg L−1 (P‐COD500). Two reference reactors, one unplanted with 250 mg L−1 (UP‐COD250) and another planted with tap water devoid of external supply of organic (P‐COD0), are constructed to show the effects of plants in treatment ability and electricity generation. Maximum average current density is achieved in P‐COD250, that is, 242 ± 10.5 mA m−2 followed by UP‐COD250, P‐COD50, P‐COD500, and P‐COD0. Polarization curves also depicts a similar order for power density. Variations of power output in low and high concentrated units are accompanied with lower substrates for bacteria in the former while the latter is due to osmotic shock of plants at higher COD concentration. At the same influent concentration, planted reactors enhances current density by 12.5%. Organic removal ability is promising in all the reactors, reaching almost 99%. However, plants enhanced, on average, 3% in COD removal. High COD removal is achieved with higher retention time. Planted reactors shows more significant increments in current during daytime after feeding than unplanted reactors, suggesting the role of root exudates via photosynthates in current generation. These results can help in further optimizing of PMFCs in terms of configuration and substrates.

Recent advances in constructed wetland‐microbial fuel cells for simultaneous bioelectricity production and wastewater treatment: A review

“…In single‐chamber CW‐MFC, there are leaks of organic matter in the cathodic region which affects the redox potential and the voltage output. Therefore, the operation of double‐chamber CW‐MFC is recommended . In a double‐chamber CW‐MFC, the cathode is separated from the anode using a separator .…”

“…Therefore, the operation of double‐chamber CW‐MFC is recommended . In a double‐chamber CW‐MFC, the cathode is separated from the anode using a separator . A great diversity of organic matter is available from low molecular weight exudates to more complex organic compounds such as glucose.…”

“…The exudation process has a dynamic nature in rhizosphere region which depends on the content of organic matter . Regmi et al carried out a study for the removal of COD at different concentrations (500, 250, and 50 mg/L) in a CW‐MFC. They observed that the CW‐MFC fed with a COD of 50 mg/L took time to stabilize generating a lower yield of bioelectricity and an atrophied vitality of the plant in the wetland.…”

Activated Carbon Mixed with Marine Sediment is Suitable as Bioanode Material for Spartina anglica Sediment/Plant Microbial Fuel Cell: Plant Growth, Electricity Generation, and Spatial Microbial Community Diversity

“…Several anode materials have been used in the Plant-MFCs to produce electricity. Among them were graphite granule and tezontle (a volcanic slag) [37], graphite felt/mat [15,17,24,25,27,28], graphite granule/grain [20,38,39], carbon fiber [40], nano-catalyzed graphite disc, rolled steel mesh with graphite fiber [41], and stainless steel mesh with biochar [42].Although many studies about the anode materials for a Plant-MFC have been conducted, to our best knowledge, there is no study yet using activated carbon (AC) in the Plant-MFCs while studying the effect of marine sediment. It is well known that the activated carbon is a suitable bioanode material for microbial fuel cells fed with acetate [43,44].…”

“…Several anode materials have been used in the Plant-MFCs to produce electricity. Among them were graphite granule and tezontle (a volcanic slag) [37], graphite felt/mat [15,17,24,25,27,28], graphite granule/grain [20,38,39], carbon fiber [40], nano-catalyzed graphite disc, rolled steel mesh with graphite fiber [41], and stainless steel mesh with biochar [42].…”