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

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/m3. 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

Biochar in Renewable Energy

Microbial Fuel Cell – M. Rao, high school student http://www.youtube.com/watch?v=s0Rdrf7tkHA This novel research studies the performance of biochar cathodes. Microbial fuel cells (MFCs) have the potential to contribute to the increasing demand for sustainable energy. Large-scale application of MFCs is yet to be implemented because of low power generation and high electrode costs. Currently, one of the largest obstacles is the development of a feasible and environmentally friendly cathode. Platinum catalyst cathodes are expensive and make up 60% of the cost of microbial fuel cell. The goal of this research was to determine if biochar, pyrolized organic matter that is a soil amendment, could operate as a feasible cathode in a microbial fuel cell. Biochar was made out of three feedstocks: mixed wood chips, Douglas fir, yellow pine at different temperatures. By cost, the biochar cathode was 98.4% cheaper than the platinum cathode ($22-44 vs.$1500). The cost effectiveness of the biochar cathode makes it potentially viable if its current densities can be increased. Future research involves testing a broader variety of feedstock as well as developing a biochar/platinum hybrid. Microbial Fuel Cell – T. Huggins, University of Colorado http://www.youtube.com/watch?v=45ZNVtpv-40 The high cost of electrode materials is one major challenge facing the full scale application of the microbial fuel cell (MFC) technology. We demonstrate here for the first time that high temperature (\u3e800°C) biochar can be a cost effective and sustainable alternative to traditional granular activated carbon (GAC) and graphite granules (GG) as MFC electrode materials. Using locally available waste-biomass, exothermic manufacturing process, and end of life agricultural benefit, biochar can be manufactured for around 51-365 US$tonne-1, up to 10 times cheaper than GAC (500-2500 US$ tonne-1) or GG (500-800 US$ tonne-1) and have significantly greater life cycle advantages. The use of biochar as the MFC anode rings in a new era of alternative electrode material options with economic and environmental benefits

Granular biochar compared with activated carbon for wastewater treatment and resource recovery

Granular wood-derived biochar (BC) was compared to granular activated carbon (GAC) for the treatment and nutrient recovery of real wastewater in both batch and column studies. Batch adsorption studies showed that BC material had a greater adsorption capacity at the high initial concentrations of total chemical oxygen demand (COD-T) (1200 mg L-1), PO4 (18 mg L-1), and NH4 (50 mg L-1) compared to GAC. Conversely the BC material showed a lower adsorption capacity for all concentrations of dissolved chemical oxygen demand (COD-D) and the lower concentrations of PO4 (5 mg L-1) and NH4 (10 mg L-1). Packed bed column studies showed similar average COD-T removal rate for BC with 0.27 ± 0.01 kg m-3 d-1 and GAC with 0.24 ± 0.01 kg m-3 d-1, but BC had nearly twice the average removal rate (0.41 ± 0.08 kg m-3 d-3) compared to GAC during high COD-T concentrations (\u3e500 mg L-1). Elemental analysis showed that both materials accumulated phosphorous during wastewater treatment (2.6 ± 0.4 g kg-1 and 1.9 ± 0.1 g kg-1 for BC and GAC respectively). They also contained high concentrations of other macronutrients (K, Ca, and Mg) and low concentrations of metals (As, Cd, Cr, Pb, Zn, and Cu). The good performance of BC is attributed to its macroporous structure compared with the microporous GAC. These favorable treatment data for high strength wastewater, coupled with additional lifecycle benefits, helps support the use of BC in packed bed column filters for enhanced wastewater treatment and nutrient recovery

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

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/m3. 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