Rethinking sanitation: panacea or Pandora's box.

In the 19th century, sanitation solutions were designed and built on the premises that human excreta was a waste suitable only for disposal and that the environment was capable of assimilating the waste. The prevailing view last century was that vapors from smells caused disease, and the best way to deal with excreta was to convey it to rivers and streams where it could be diluted and cleansed. Times have changed, the premises are outdated, and current solutions contribute, either directly or indirectly, to many of the problems faced by society today: water pollution, scarcity of fresh water, food insecurity, destruction and loss of soil fertility, loss of biodiversity, depletion of the ozone layer, and global warming. A common denominator of all these problems is how society deals with its wastes, specifically how it deals with human excrement. We have to rethink past premises, design and build new systems, and contribute to the solving of society's most pressing problems. The panacea of the 19th century is turning out to be the pandora's box of the 21st century.