Biochar Based Microbial Fuel Cell for Enhanced Wastewater Treatment and Nutrient Recovery

Abstract

Waste-wood derived biochar was evaluated for the first time as both an anode and cathode material, simultaneously, in an overflow style microbial fuel cell (MFC) using actual industrial wastewater. Results show that the average chemical oxygen demand (COD) removal was 95% with a reduction rate of 0.53 kg¨COD¨m´1¨d´1 in closed operation mode. The ammonia and phosphorous reductions from wastewater was 73% and 88%, respectively. Stable power production was observed with a peak power density measured at 6 W/m 3 . Preliminary contributions of physical, biological, and electrochemical COD removals were evaluated, and the results show such combined mechanisms give BC an advantage for MFC applications. Nutrient recovery data showed high levels of macronutrients adsorbed onto the spent biochar electrodes, and phosphorus concentration increased from 0.16 g¨kg´1 in raw BC to up to 1.9 g¨kg´1 in the cathode. These findings highlight the use of biochar as electrodes in MFCs to facilitate simultaneous wastewater treatment and power production with additional agronomic benefits.

Past, present, and future of biochar

“…It is feasible to use raw biochar as a fuel in direct carbon fuel cells (DCFC) or hybrid carbon fuel cells (HCFC) (Jafri et al 2018;Kacprzak et al 2016). Biochar as an electrode or catalyst has a promising prospect in microbial fuel cells (Deng et al 2018;Huggins et al 2016). In addition, biochar has shown great potential as an electrode material used directly or indirectly for the production of electrochemical energy storage devices such as supercapacitors (SC) and lithium ion batteries (LIB) (Caguiat et al 2018;Liu et al 2017;Gao et al 2017;Guo et al 2015).…”

New directions and challenges in engineering biologically-enhanced biochar for biological water treatment

“…The electro activity of biochar and electroactive microbes enables its use in Microbial Electrochemical Technologies (METs) such as Microbial Fuel cells for electricity generation and biological water treatment 49,56,101 . Biochar can act as a microbial inoculum carrier and can be used as electrodes (anode and cathode) of a microbial fuel cell, where respiring microbes convert chemical energy to electrical energy 101 . Contaminated water can be used as fuel, where microbes feed on the contaminants in wastewater.…”

Use of Biochar-Based Cathodes and Increase in the Electron Flow by Pseudomonas aeruginosa to Improve Waste Treatment in Microbial Fuel Cells

“…Thanks to its electrochemical properties and low cost, biochar has been identified as a good candidate material to be used in the set-up of scaled BESs for wastewater treatment and soil bioremediation [7,23,27,29]. A benefit of biochar, in comparison to other carbon-based materials, such as activated carbon (AC), lies in its easy production from different vegetable residues and from sewage sludge [7,13,22,27,[30][31][32]. Finally, different researches have proved biochar-based materials to be suitable also for dye degradation, landfill leachate, and other pollutants treatment in MFCs, which adds a further benefit to the ones described above [27,33,34].…”