Energy from toilet water (Day 14)

Toilet FlushThere is potential in most things, even the waste that disappears down the toilet bowl.

But along with the waste, there’s the water we use to flush it away. Before water arrives in the toilet bowl it takes energy to process it. And once it disappears down the drains it takes more energy to re-process again. It’s something we pay for as part of our everyday utility bills.

Turning the potential of toilet water into a source of renewable energy, and a way to reduce bills, sounds like a good idea to me.

A team at MIT’s Laboratory for Energy and Microsystems Innovation (LEMI)  agree.

They are working on a way to use microbial fuel cells to harvest some of the energy that is currently being flushed away. It has the potential to contribute to the energy grid.

Like a chemical fuel cell, a microbial fuel cell consumes fuel and an oxidant and produces useful energy that gives off by-products, such as heat. As the cost of chemical fuel-cell catalysts increase, the technology is receiving greater attention.

According to MIT, instead of requiring a precious-metals catalyst such as platinum, microbial fuel cells use bacteria, which live on electrodes and eat fuel. As a byproduct of respiration, they release electrons to the electrode, providing energy you can harvest for electricity.

The energy produced would be ideal for lightweight wastewater treatment and food-processing facility could use [microbial fuel cells] to treat wastewater from food processing before releasing it back into the sewerage system.

I hope you enjoyed this good news story. Remember to send your ideas for great ChemEng365 stories to me here.