5. CONCLUSIONS
The bioelectricity generated by the SMFC can be used to supply the power to the environmental monitoring sensors. This power source can be a sustainable and green source of electricity. The performance of the system with two anodes was about twice higher than that of with one anode regarding bioelectricity generation. The variation of AVS value was observed and decreased about 0.2 mg/g-dry mud indicated the improvement of the geoenvironment for the marine sediments after using SMFCs in the contaminated sediments both in the laboratory and in the field . By observing the different circuit conditions, it was found that the rate of AVS decreasing was the fastest and slowest when a close circuit and no circuit (blank) condition was set, respectively. It showed the similar trend as Abbas et al. 2019 have been observed. Higher temperature is better for enhancement of voltage generation because the bacterial activities enhanced with the enhancement of the temperature. It was observed that voltage at 250 C was almost 8 times higher than that of at 50 C. From the laboratory test and the field test result comparison, it was found that voltage generation is more durable in the tidal flat areas however, during the winter, the voltage generation might be deceased due to colder surrounding temperature in Japan. So, proposed SMFC system can both generate bioelectricity and improve the geoenvironmental condition of the marine sediment at the same time and extra measure should be taken at the winter season for sustainable power supply from SMFC. Economic analysis and the feasibility of the large scale SMFCs in the field should be carried out in the future.
REFERENCES
Abbas, S. Z., Rafatullah, M., Khan, M.A., Siddiqui, M. R., 2019. Bioremediation and Electricity Generation by Using Open and Closed SMFCs. Frontiers in Microbiology, 9, 3348.
Baeta-HallL, S., Anselmo, M.L., Rosa, M. , 2004. Bio-degradation of olive oil husks in composting aerated piles. Bioresource Technology, 96: 69-78.
Erable, B., Byrne, N., Etcheverry, L., Achouck, W. , Bergel, A., 2017. Single medium MFC: stainless steel and graphite electrode materials select bacterial communities resulting in opposite electrocatalytic activities. International Journal of Hydrogen Energy, 42, 26059-26067.
Hong, S. W., Chang, I., Choi, Y., Chung, T., 2009. Experimental evaluation of influential factors for electricity harvesting from sediment using MFC. Bioresource Technology 100, 3029-3035.
Kubota, K., Watanabe, T., Maki, H., Kanaya, G., Higashi, H., Stutsubo, K., 2019. Operation of SMFCs in Tokyo Bay, an extremely eutrophicated coastal sea. Bioresource Technology Reports 6, 39-45.
Logan, B.E., Regan, J.M., 2006. Electricity-Producing Bacterial Communities in MFCs. Trends Microbiology 14 , 512-518.
Lovely, D.R. 2006. Bug Juice: harvesting electricity with microorganisms. Nature Review Microbiology, 4, 497-508.
Moqsud, M.A. 2020.bioelectricity generation and remediation of sulfide contaminated tidal flat sediment. International Journal of sediment research 35: 91-96..
Moqsud, M. A, Omine, K., Yasufuku, N., Hyodo, M., Nakata, Y. 2014.bioelectricity from bamboo and kitchen garbage. Waste Management and Research 32(2),124-30.
Moqsud, M.A., Omine, K., Yasufuku, N., Hyodo, M., Nakata, Y. 2013. MFC (MFC) for bioelectricity generation from organic waste. Waste Management., 33 (11), 2465-2471.
Moqsud, M.A., Sato, K., Hasan, M., Nakata,Y., Omine, K., 2017. Seasonal variation of contaminated geo-environmental condition of Yamaguchi bay tidal flat, Japan. Regional studies in Marine science. 10, 27-31.
Rabaet, K., Van de Sompel, K., Maignien, L., Boon, N., Alterman, P., 2006. MFCs for sulfide removal. Environmental science and technology 40, 5218-5224.
Rickard, D., Morse, W. J., 2005. AVS. Marine chemistry 97, 141-197.
Song, N., Jiang, H. 2018. Effects of initial sediment properties on start-up times for SMFCs. International Journal of Hydrogen Energy 43, 10082-10093.
Spiegel, R.J., Preston, J.L., 2003. Technical assessment of fuel cell operation on anaerobic digester gas at the Yonkers wastewater treatment plant. Waste management, 23,709-717.
Wang, D.B., Song, T.S., Guo, T., Zeng, Q.L., Xie, J.J. 2014. Electricity generation from SMFCs with algae-assisted cathodes. International Journal of Hydrogen Energy 39, 13224-13230.
Zhuang, L., Zhou, S. 2009. Substrate cross-conduction effect on the performance of serially connected MFC stack. Electrochemical Communication 11, 937-940.