Establishment and Study of Sediment Microbial Fuel Cell

Full Title

Establishment and Study of Sediment Microbial Fuel Cell

Event

IWA World Water Congress 2010

Authors and Affiliations

Tai-Lee Hu

Professor of Microbiology

Department of Environmental Engineering & Science

Feng Chia University, Taichung 40724 Taiwan

e-mail: tlhu@fcu.edu.tw

Chen-Fu Lai

Graduate student of Department of Environmental Engineering & Science

Feng Chia University, Taichung 40724 Taiwan

Chenfang Lin

Professor Department of Soil & Environmental Sciences

National Chung Hsing University, Taichung 40227 Taiwan

e-mail: clin@gmail.com

Abstract

Establishment and Study of Sediment Microbial Fuel Cell

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Background
With the increasing worldwide energy crisis, different types of renewable energy technology have been continuously examined. Microbial fuel cells are one of the emerging technologies for renewable energy that decomposes organic matter to generate electricity using microorganisms. The sediment microbial fuel cell (SMFC) is more applicable. The purpose of this study is to establish a sediment microbial fuel cell in the laboratory and investigate the factors affecting sediment microbial fuel cell performance.

Results
A SMFC was established using a serum bottle as the reactor (working volume of 0.5l), in which 100 ml or 300 ml of river sediment and 400 ml or 200 ml of river water were filled. With no extra substrate was added, a SMFC with 300 ml sediment generated a power density of 2.5 mW/m2. This was 3 fold higher than a SMFC with 100 ml sediment (0.8 mW/m2). The power generated using carbon felt as electrodes was 10 fold higher than that using carbon paper as electrodes. The power density of a cathode coated with platinum (0.02 mg/cm2) was 3 fold higher than that using a cathode without coating. The cathode position affects SMFC performance. A cathode flattened beneath the water generated more current than a cathode that placed horizontally or sat vertically in the water. A lab-scale SMFC was established using carbon felt as electrodes. The Pt-coated cathode was placed beneath the water. The anode was placed in the river sediment. The external resistance was 3k Ω. Sucrose or acetate (800 mg COD/l) solution was used to simulate river water and added to a batch type SMFC with 300 ml sediment. When the SMFC was fed with acetate as the substrate for 135 days, it generated higher voltage (268.9 mV) than a SMFC using sucrose (206.9 mV). Compared to the SMFC without feeding (186 mV, 0.7 mW/m2), the power density generated (1.7 mW/m2) by a SMFC fed with acetate increased about 2 fold. After the same SMFC was operated for 266 days, the power
density increased from 1.7 mW/m2 to 3.0 mW/m2. However, very few microorganisms were observed on the anode. When the acetate concentration was increased from 1 mM to 2 mM, the voltage reversal phenomenon was observed. The power density generated by the SMFC with 100 ml sediment fed with 400 or 800 mg COD/l sucrose or 2 or 4 mM acetate could achieve 3.6, 3.6, 3.9 and 4.8mW/m2, respectively. Compared to the control group (no feeding), the power density of the SMFC with 100 ml sediment increased nearly 5 fold. The dissolved oxygen in the catholyte showed a significant correlation with the power output (r>0.60, p<0.05). The concentration of dissolved oxygen on the catholyte of the SMFC with 100 ml sediment was higher than that of 300 ml sediment (Fig.). A higher dissolved oxygen concentration in the catholyte is essential for SMFC higher power output.

Content

Links

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