Bioelectrochemical Systems for Simultaneous Wastewater Treatment and Energy Recovery: Adaptation for Nigerian Low-Income Urban Sanitation

This dissertation investigates the science, engineering design, and implementation pathways for bioelectrochemical systems adapted for simultaneous wastewater treatment and energy recovery in low-income urban sanitation applications in Nigerian cities, making original contributions to both bioelectrochemical science and sustainable sanitation engineering. Microbial fuel cells and microbial electrolysis cells represent an emerging class of wastewater treatment technologies that harness the metabolic activity of exoelectrogenic bacteria to simultaneously degrade organic waste and generate electrical current, a combination that could transform energy-intensive conventional wastewater treatment into an energy-generating process relevant to Nigerian cities where reliable electricity for conventional treatment is unavailable. The theoretical contribution is an original electrokinetic-transport coupled model of biofilm electrode dynamics under the high-temperature, high-organic-loading conditions of Nigerian domestic wastewater, which differs substantially from the low-temperature, low-strength wastewaters for which most bioelectrochemical system models were developed. Experimental work encompasses isolation and characterisation of indigenous exoelectrogenic bacterial species from Nigerian wastewater environments, optimisation of electrode material, reactor configuration, and operating conditions for Nigerian wastewater characteristics through a systematic design of experiments, pilot-scale testing of an adapted reactor design over eighteen months treating domestic wastewater from a Lagos low-income settlement, and life cycle assessment comparing the adapted technology against conventional alternatives. Original contributions include the indigenous exoelectrogen characterisation, the adapted bioelectrochemical model, and the life cycle comparison for Nigerian conditions. Keywords: microbial fuel cell, bioelectrochemical system, wastewater treatment, energy recovery, Nigeria.