Quote:
Originally Posted by shovel
That's pretty rad!  What do you suppose they do with the post-distillation material? |
I would link to an article about it but I'm lazy, and I read it in an actual book (who uses THOSE any more?) so I can't quote it exactly, BUT:
As I recall, the raw sewage first goes through a standard stir-station type holding pond, where bacterium can begin to grow. Then the sewage runs through a series of ponds with lilies in them. The lilies absorb the mercury and other heavy metals, and so are regularly harvested and thrown in the landfill. By the time the sewage water has made its way to the cattails, the bacterium have already broken down most of the actual poop, and so the nitrates and other beneficial chemicals are already free-floating.
The cattail system in question is NOT used to make ethanol, rather to filter sewage water, but it's so effective I see no reason why we couldn't take it a step further.
The water that runs out of the cattails goes into another swampy area with fish (that are regularly caught and eaten), and by the time it leaves that it's 100% drinkable, pure water (none of the waterborne pathogens you would expect from sewage). This then runs into a natural water system. The algae, cattails, lilies and bacterium have already pulled the nitrogen out of the water, so there is none of the algae bloom you often see downstream of such a facility. It's a win-win, in my opinion.
EDIT: Though I would be dubious about eating poop-factory fish.