Source – expandedconsciousness.org
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While clean water is scarce throughout many developing countries, Americans send 5.8 billion gallons of it down the toilet each day. Currently, less than 4 percent of this wastewater is recycled for purposes such as irrigation, landscaping, and in some cases, drinking water.

Why aren’t we doing a better job of recycling our water? Water purification requires a massive amount of energy: Developed countries currently spend around 3 percent of all their energy resources in treating and purifying wastewater, making it infeasible to recycle more significant quantities of wastewater. However, a new technology could reverse that cycle by allowing us to generate new energy from waste sources found in the water.

Tiny “exoelectrogenic microbes” are naturally found in wastewater. As they feed on bacteria from the waste matter, they generate electricity as they react with oxide minerals. Previously, this electricity has been difficult to harvest, but engineers at Stanford University have developed the technology to build a “microbial battery” that can store the energy generated by the microbes.

The small battery consists of a vial of wastewater with two electrodes. The negative electrode is equipped with carbon filaments, which the microbes use as electrical conductors to send electrons to the positive electrode; the positive electrode contains a silver oxide node, which transforms to silver as it receives electrons. When the positive electrode is removed from the cell, the silver re-oxidizes and the charged electrons are released as energy. The battery isn’t ready for mass production yet, though: While silver oxide has proven to be an effective conduit, it is too expensive for large-scale use. The researchers are currently seeking an alternate material for the batteries.

Stanford team estimates that such microbial batteries have the potential to unlock around 30 percent of the stored energy available in wastewater. Such batteries could be used to power the purification of wastewater three times over—making it far more cost- and energy-efficient to recycle our used water. For drought-affected regions, and developing countries with limited clean water resources, the impact could be tremendous.
http://expandedconsciousness.org/