The treatment of waste water can be used to create energy and biodegradable plastics.
Treating waste water is energy intensive. But it doesn’t have to be such a drain on resources, soon it might be able to earn its keep. A team led by Hong Liu from Oregon State University in Corvallis has plans for microbial fuel cells that will reclaim energy from waste water and produce around 2.87 watts per liter of waste water. That is almost double the amount of electrical power usual for such a cell. Its by-products could be harnessed to create cheap, biodegradable plastics.
Waste water holds huge amounts of energy, bound up in organic molecules, but it can be difficult to access. The Oregon fuel cells run on microbes that would normally digest organic matter to produce water. In a fuel cell, though, isolated from oxygen, that conversion stalls and electrons, which are bundled with protons and oxygen to form water, are pulled away from the microbes by the potential between a cathode and an anode, creating an electrical current.
As well as tweaking the mixture of microbes on the electrodes, the Oregon design has also managed to squash far more electrodes into the fuel cell than on previous versions. Liu says her lab aims to scale up the device within the next five years and make it cheaper. The by-products of waste water treatment can be harnessed too. Engineers are working on a way to convert methane into biodegradable plastics.
Via: www.oregonstate.edu
