In this study, influence of distance between two sediment microbial fuel cells (SMFCs) and storage of sediment for several months in an open channel were investigated in different configurations. Results indicated that SMFCs with the largest distance outperformed the neighboring SMFCs in terms of voltage and power output in different configurations. In addition, it was shown that long-term sediment storage weakened SMFC performance. Maximum power densities of 39 and 50 mW/m2 were achieved for the two SMFCs with the largest distance, while 30 and 26 mW /m2 were obtained for the two adjacent SMFCs operating with fresh sediment. Furthermore, loss on ignition (LOI) removal was enhanced with a sufficient increase in SMFC distances, so that LOI removal of 49.8 % and 21.4 % in the SMFCs with the largest distance was considerably higher than the neighboring SMFCs (18.2 % and 12.9 %). On the other hand, employing the stored sediment, SMFCs with the largest distance produced the highest maximum power densities of 35 and 32 mW/ m2 whereas 23 and 22 mW/m2 were obtained by the neighboring SMFCs. Power density of the SMFCs with the largest distances was higher than the neighboring cells in both series and parallel connections as well.

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