Some thoughts about future perspectives of water and wastewater management.

The ideals of sustainability have a longer history than is sometimes realised, as they can be traced back to the insights of Von Carlowitz in 1713. However in the intervening centuries early successes in sanitation based on the "flushing sewer" led engineers to focus too much on sewerage-based solutions that are increasingly uneconomic and unequal to the challenges arising from population growth and urbanisation. The future strategy for globally sustainable sanitation will surely involve source separation and recycling and reuse: these are the technologies that environmental scientists and engineers should now be addressing.