Maggie Black seems to be one of the most eloquent writers on the issue of Eco-sanitation. That is, containing and managing human ‘waste’ at source and not contaminating a huge amount of fresh water with it, at great cost. If you are new to this subject, or have never thought about the principle of what you are doing when you flush, then read the links below.

http://www.newint.org/features/2008/08/01/keynote-toilets/

http://findarticles.com/p/articles/mi_m0JQP/is_2003_March/ai_99232390/pg_1?tag=artBody;col1