text: Oct 12th 2007 at 8:10AM
  Let's check out another method which promises to deliver cheap ethanol from something that's not edible. According to Mercedes Ballesteros, a scientist working for the Unidad de Biomasa del Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (Ciemat), ethanol can be obtained from urban solid waste (aka, home garbage).
  First of all, all non-organic and/or pollutant waste must be separated from the organic part (in some European cities there are special containers to classify trash for this purpose). This organic fraction is then chemically treated with diluted acid to convert cellulose into glucose which is then fermented to obtain ethanol. Her estimates are that 10 to 12 kg of domestic waste can produce 1 liter of ethanol using this method (about 93 pounds of waste for a gallon). The most efficient process? No, but we're at least getting something from, basically, nothing.