The power of poo

People don't think about it a lot, but some of the more interesting developments I've come across the last while have been in the area of drinking water. Most recently, this has come in the form of improvements in wastewater reclamation, as described in an article from Bill Gate's website entitled This Ingenious Machine Turns Feces Into Drinking Water

Why would anyone want to turn waste into drinking water and electricity? Because a shocking number of people, at least 2 billion, use latrines that aren’t properly drained. Others simply defecate out in the open. The waste contaminates drinking water for millions of people, with horrific consequences: Diseases caused by poor sanitation kill some 700,000 children every year, and they prevent many more from fully developing mentally and physically. If we can develop safe, affordable ways to get rid of human waste, we can prevent many of those deaths and help more children grow up healthy. Western toilets aren’t the answer, because they require a massive infrastructure of sewer lines and treatment plants that just isn’t feasible in many poor countries.

Water reclamation isn't exactly new and, when done, has generally been used to address a water shortage which is a purpose it might also serve here. What interested me here is that this particular method of treatment produces power rather than consuming it (and there also some byproducts which may be used as fertilizer - biosolids is the current EPA euphemism for that sort of thing). Digging a bit more I found a 2012 article talking about the energy required for wastewater treatment and a similar device (though I suspect that the end result there probably wouldn't meet drinking water standards):

The device produced 0.9 kilowatt-hours of electricity per kilogram of organic waste. In contrast, sewage treatment usually consumes 1.2kWh per kilogram.

I'm not sure quite how the device Gates is promoting compares to this competitor - they do at least appear to be separate products - and, of course, there's also that problem Gates himself noted:

The history of philanthropy is littered with well-intentioned inventions that never deliver on their promise.

I suppose we'll have to wait and see how this turns out.