Just a side comment. Human waste is dangerous to us because of disease causing organisms that may be contained in it, is that right? The other day I was doing something about the house and not paying a great deal of attention to NPR but someone from some UN agency commented that the corpses still un-buried from the tsunami disaster didn't pose a threat to human health!! I found that puzzling to say the least. I may have misheard him but it seems quite unlikely.