Brewery wastewater treatment using air-cathode microbial fuel cells

Microbial fuel cells (MFCs) can be used in wastewater treatment and to simultaneously produce electricity (renewable energy). MFC technology has already been applied successfully in lab-scale studies to treat domestic wastewater, focussing on organic matter removal and energy production. However, domestic wastewater also contains nitrogen that needs to be treated before being discharged. The goal of this paper is to assess simultaneous domestic wastewater treatment and energy production using an air-cathode MFC, paying special attention to nitrogen compound transformations. An air-cathode MFC was designed and run treating 1.39 L d−1 of wastewater with an organic load rate of 7.2 kg COD m−3 d−1 (80% removal efficiency) and producing 1.42 W m−3. In terms of nitrogen transformations, the study demonstrates that two different processes took place in the MFC: physical–chemical and biological. Nitrogen loss was observed increasing in line with the power produced. A low level of oxygen was present in the anodic compartment, and ammonium was oxidised to nitrite and nitrate.

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Application of Air Cathode Microbial Fuel Cells for Energy Efficient Treatment of Dairy Wastewater

Periodica Polytechnica Chemical Engineering ◽

10.3311/ppch.16695 ◽

2021 ◽

Vol 65 (2) ◽

pp. 200-209

Author(s):

Bálint Lóránt ◽

Miklós Gyalai-Korpos ◽

Igor Goryanin ◽

Gábor Márk Tardy

Keyword(s):

Wastewater Treatment ◽

Fuel Cells ◽

Removal Efficiency ◽

Microbial Fuel Cells ◽

Energy Efficient ◽

Dairy Wastewater ◽

Small Scale ◽

Air Cathode ◽

Efficient Treatment ◽

Organic Removal

Microbial Fuel Cells (MFCs) offer a promising new solution for wastewater treatment due to their advantageous characteristics: lower energy demand and less excess sludge compared to the conventional activated sludge wastewater treatment technology. In this study, two systems of single chamber air cathode MFCs with a working volume of 14 L were investigated for the energy efficient treatment of dairy wastewater. Biomass-originated carbon cathode and noble-metal free cathode catalyst were applied to meet the demand for a lower investment cost. Influent chemical oxygen demand (COD) was in the range of 900 to 3830 mg L–1, while hydraulic retention time was ~ 2.4 days. Systems provided 156 mW m–3 and 170 mW m–3 maximum power densities and coulombic efficiencies of 11.5 % and 12.8 % in average. Organic removal efficiency of 71.1 ± 8.0 % was observed when influent COD was between 900 and 1500 mg L–1, however effluent quality and removal efficiency (67.9 ± 12.6 %) deteriorated as influent COD was increased (1500 – 3830 mg L–1). At high influent CODs (over 3000 mg L–1), an organic elimination rate of 0.82 ± 0.11 kg COD m–3 d–1 was calculated, that can be considered as the upper limit of organic removal in the systems. Based on the results, MFCs may offer a potential solution for small-scale dairy factories for the pretreatment of their effluent to meet the criteria for wastewater discharge to sewer systems. The modular MFC design also facilitates to tailor the system to actual capacity requirements.

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Microbial fuel cells: Devices for real wastewater treatment, rather than electricity production

The Science of The Total Environment ◽

10.1016/j.scitotenv.2021.145904 ◽

2021 ◽

Vol 775 ◽

pp. 145904

Author(s):

Jaecheul Yu ◽

Younghyun Park ◽

Evy Widyaningsih ◽

Sunah Kim ◽

Younggy Kim ◽

...

Keyword(s):

Wastewater Treatment ◽

Fuel Cells ◽

Microbial Fuel Cells ◽

Electricity Production ◽

Real Wastewater

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Polyelectrolyte–single wall carbon nanotube composite as an effective cathode catalyst for air-cathode microbial fuel cells

Water Science & Technology ◽

10.2166/wst.2014.416 ◽

2014 ◽

Vol 70 (10) ◽

pp. 1610-1616 ◽

Cited By ~ 2

Author(s):

Huanan Wu ◽

Min Lu ◽

Lin Guo ◽

Leonard Guan Hong Bay ◽

Zheng Zhang ◽

...

Keyword(s):

Fuel Cells ◽

Carbon Nanotube ◽

Oxygen Reduction ◽

Microbial Fuel Cells ◽

Reduction Process ◽

Air Cathode ◽

Single Wall Carbon Nanotube ◽

Single Wall Carbon ◽

Cathode Catalysts ◽

Metal Free

Polyelectrolyte–single wall carbon nanotube (SCNT) composites are prepared by a solution-based method and used as metal-free cathode catalysts for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). In this study, two types of polyelectrolytes, polydiallyldimethylammonium chloride (PDDA) and poly[bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] (PEPU) are applied to decorate the SCNTs and the resulting catalysts exhibit remarkable catalytic ability toward ORR in MFC applications. The enhanced catalytic ability could be attributed to the positively charged quaternary ammonium sites of polyelectrolytes, which increase the oxygen affinity of SCNTs and reduce activation energy in the oxygen reduction process. It is also found that PEPU–SCNT composite-based MFCs show efficient performance with maximum power density of 270.1 mW m−2, comparable to MFCs with the benchmark Pt/C catalyst (375.3 mW m−2), while PDDA–SCNT composite-based MFCs produce 188.9 mW m−2. These results indicate that PEPU–SCNT and PDDA–SCNT catalysts are promising candidates as metal-free cathode catalysts for ORR in MFCs and could facilitate MFC scaling up and commercialization.

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