Sewage to suds? German company uses treated wastewater to make beer.

There are four main ingredients in the production of beer: malt, hops, yeast and... sewage? That last one might not sound like the most intuitive choice, but it's the one that's already being made - with sewage water, of course, having gone through a total of four purification stages.

The first three treatment stages are mechanical, biological and chemical. The mechanical treatment stage includes a screening plant, a grit chamber and two primary clarifiers. In the biological treatment stage...