Electrochemical Technologies Unleashed: Energy Recovery from Clean and Dirty Water with Dr. Douglas F. Call
Electrochemical technologies are emerging as key players to generate electricity and store energy. Conventional systems include fuel cells powered by gaseous fuels and batteries used in everything from cell phones to automobiles. There are several “unconventional” electrochemical technologies that can use wastewater or fresh/saline waters as fuel sources. Microbial fuel cells (MFCs) are an “unconventional” electrochemical technology that generate electricity when bacteria degrade wastewater organics and transfer electrons to anode electrodes. When these electrons react at a second electrode in the presence of oxygen, the final product is water. Another largely untapped energy resource is the chemical energy available in freshwater-seawater gradients. Mixing one cubic meter of freshwater (the volume of six oil barrels) into the ocean releases energy equivalent to the same volume of water falling from a height of nearly 1,000 feet. Reverse electrodialysis (RED) generates electricity when solutions of different salinities are separated by multiple membranes that allow only ions (e.g. sodium and chloride), and not water, to pass through them. The flow of ions through the membranes to even out the salinity gradients is converted into electricity at two terminal electrodes. Dr. Call will discuss recent efforts to scale-up MFCs for wastewater treatment and introduce a newly formed UNC-system collaboration to develop and assess RED potential in North Carolina.