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Earth Technology

Solar-Powered Toilet Torches Waste For Public Health 126

Daniel_Stuckey writes "With funding from the Bill and Melinda Gates Foundation's Reinvent the Toilet challenge, [a] team has developed a toilet that uses concentrated solar power to scorch and disinfect human waste, turning feces into a useful byproduct called biochar ... a sanitary charcoal material that is good for soils and agriculture. By converting solid waste to biochar (liquid waste is diverted elsewhere, as it's easier to deal with), the toilet thus allows for sanitary waste disposal without huge infrastructure investments. The toilet itself, called the Sol-Char, is a fascinating bit of engineering. In order to sanitize waste without the help of massive treatment facilities, Linden's team instead designed the toilet to scorch waste in a chamber heated by fiber optic cables that pipe in heat from solar collectors on the toilet's roof. 'A solar concentrator has all this light focused in on one centimeter. It'd be fine if we could bring everyone's fecal waste up to that one point, like burning it with a magnifying glass,' Linden said. 'But that's not practical, so we were thinking of other ways to concentrate that light.'"
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Solar-Powered Toilet Torches Waste For Public Health

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  • by Anonymous Coward on Sunday March 16, 2014 @04:23AM (#46497177)
    For places without sewage plumbing but still not isolated enough that a hole in the ground is sufficient and where separation+infiltration is not viable either, there are mulching toilets, but in those you still need to change not too pleasant buckets once in a while. But there are also incinerating toilets using either gas (propane) or electricity, and they're quite OK. All that is left is a small can of ash, that can be used in the garden. This solar toilet looks to be just another way of providing the heat in such a toilet.
  • by Anonymous Coward on Sunday March 16, 2014 @04:24AM (#46497181)

    Eh no.
    Look up pyrolysis. Instead of simmering for hours in tropical heat, the poo will be subject to pyrolysis in mere minutes in a low oxygen environment. Gases produced will be mainly syngas, which is odourless.

  • by flyingfsck ( 986395 ) on Sunday March 16, 2014 @04:32AM (#46497201)
    Composting human waste is fantastic for spreading human diseases all over the food supply...
  • LOL indeed! Did you know that when your ancestors were still throwing their shit out the window every morning into the gutter, and took a bath maybe one or two times a year, the Muslim world (much of which is black, incidentally) had sewer systems and the closest thing to modern medicine available at the time? Yeah, I bet you didn't. History seems highly unlikely to be your strong point.

  • In all fairness, though, traditional composting toilets can't handle the volume produced in urban settings. They may be great for homes, but not so much for apartment housing, dormitories, airport terminals, etc. Biochar toilets can be adapted to meet at least some of these needs.

    Another point: biochar acts something like a catalyst to improve soil but is not consumed in the process. The carbon is effectively sequestered for thousands of years, but biocharred enriched soils are better at appropriate release of moisture and nutrients while also diluting many soil toxins.

    This might seem like the magic cure-all to all post-modern ills, but it isn't all blue sky hype. Each gram of biochar adds the surface area of a tennis court to the soil; a little bit of it goes a long way.

    One last point: composting toilets only work well if they are properly managed. I had the misfortune of having a country neighbor for several years who was learning how to manage her composting toilet, and there were definitely episodes of odor problems.

  • by Will.Woodhull ( 1038600 ) <> on Sunday March 16, 2014 @01:32PM (#46499309) Homepage Journal

    Well, yes, but with this difference: incineration pumps all the carbon in the poop into the atmosphere. Biochar production uses the heat to run a pyrolytic, anaerobic reaction where a good portion of the carbon is turned to charcoal and sequestered away for several thousand years. Since the charcoal retains the microscopic physical structures of cell walls, etc, it also has some very good soil building qualities, such as retaining fertilizers for slow release and increasing the moisture holding capability of the soil.

Never buy from a rich salesman. -- Goldenstern