More on Sewage
Free the Animal has a suggestion for how to obtain vitamin B12 the vegan way:
Here's what I propose: Let's encapsulate fresh, raw poop -- from ruminants or primates (intervention studies could later determine which is more effective in raising B12 levels). Can you imagine the premium you could charge if it had to be air tight, refrigerated, so the bacteria could keep doing their thing all the while?There are precedents in stone-age beer and Kopi Luwak coffee.
In other words, it's been done.