Ihenacho, Chizobam Chikeziri2025-07-032025-07-032023-08Ihenacho, C. C. (2023). Simultaneous waste water treatment and energy harvesting in microbial fuel cells (Unpublished Master's Thesis). Federal University of Technology, Owerri, Nigeriahttps://repository.futo.edu.ng/handle/20.500.14562/2090This thesis is for the award of Master of Science (MSc.) in Environmental MicrobiologyThe prohibitively high cost of treating certain wastewaters has often resulted in their indiscriminate disposal without treatment, especially in most developing countries. This has contributed to the presently heightened environmental problems. Microbial fuel cells (MFCs) have increasingly attracted attention as a viable tool to address these challenges. The dual chambers MFCs were used to treat piggery wastewater samples for 25days, and selected physicochemical parameters were monitored. The effects of surface area of anode (0.005m2 to 0.015m2 ), surface area of cathodes (0.005m2 to 0.015m2 ) and volume of anode (750ml to 1125ml) on voltage generation, were optimized. Optimization was designed with Box Behnken Design, which gave 30 runs of dual chambers MFCs. All components of MFCs were set up according to the design. Following 25 days running of the MFCs and daily recording of voltage production (morning and evening), the average voltages, taken across 10,000Ω resistance, as produced by the 30 MFCs were optimized with Minitab® 17. Results showed that 0.011m2 , 0.015m2 and 1500ml were the optimum surface area of anode, cathode and volume of anode respectively, with estimated highest average voltage production of 41.83mV. When these optimums were used to set MFCs, the highest average voltage obtained 52.5mV, which is 25% higher than estimated highest average voltage, while the lowest was 20.13mV. These were higher than highest average voltage of 34.32mV and lowest of 7.76mV obtained without optimization. The BOD, COD of the wastewaters reduced from 1705.33mg/l and 5311.67mg/l in original wastewater to 1383.33mg/l and 3643.33mg/l respectively, after treatment with MFC. These represent 18.89% and 31.41% reduction in BOD and COD respectively. In the control (untreated) sample, they only reduced to 1583.33mg/l and 4699.67mg/l respectively. Similarly, concentrations of NO3 + , PO4 3+ and NH4 + in the wastewater also decreased after treatment, from 28mg/l, 2.34mg/l and 2.77mg/l to 8.33mg/l, 1.83mg/l and 1.52mg/l respectively. The pH of treated wastewater increased from 7.1 to 8.33 after treatment. These were different from 7.37 recorded in pH, 23.33mg/l, 2.02mg/l and 2.23mg/l recorded in control samples, for nitrate, phosphate and ammonium respectively. Initial piggery wastewater samples used and swab of biofilm on anode surface recorded a total viable bacterial counts ranging from 1.0 x 106Cfu/ml to 9.75 x 107Cfu/ml. Species of Bacillus, Pseudomonas, Enterococcus, Klebsiella, Serratia, Staphylococcus, Enterobacter, Corynebacterium, Salmonella, Shigella, Micrococcus and Escherichia coli include isolates found on the samples. Consequently, MFCs hold great promises as a cheaper tool for treatment of wastewater, and factors affecting its potentials should be further investigated.The results of this study are recommended for further studies on scale up of MFCs for commercial applications.enAttribution-NonCommercial-ShareAlike 4.0 InternationalMicrobial fuel cellwastewatervoltagebioelectricityoptimizationDepartment of MicrobiologyMaster’s Thesis