The invention of the flush toilet, or water closet, in 1596 ended open defecation and transferred excreta outside of homes for the first time. This was certainly a good thing in the short term, but today the flush toilet probably stands as one of the most unsustainable innovations in human history.
Think about it. Why would we want to increase the liquid volume of a potentially harmful substance – human waste? Most of the waste water that flush toilets create – more than 80% worldwide – ends up going directly back into the environment. No treatment, no use, just a lot of open sewers.
With the invention of flush toilets, the volume of waste created when humans go to the bathroom increased almost 20-fold. To deal with this new level of waste, we invented waste-water treatment plants. The aim of these sewage treatment systems has traditionally been to provide clean effluent that can be put back into the ecosystem.
Photo credit: Tom Raftery via Foter.com / CC BY-NC-SA