WE NEED TO OPTIMISE THE WAY THAT WATER IS USED IN SOUTH AFRICAN CITIES

ANTHONY Turton’s op-ed (The Star, November 4, 2017) lists three ways of improving our cities’ water security: waste-water recovery (from sewage, but also, I assume, from mine waste drainage), desalination of seawater and managed aquifer recharge.

He fails, however, to mention large-scale stor mwater harvesting – for accessing water that could be directed into managed aquifer recharge, to regular water purification works or into wastewater recovery processes. Cape Town, for example, sees an average of about four times the quantity water falling onto the city as rain as the city distributes. Yet almost all of that rainwater runs down the city’s rivers into the sea. Why not capture at least some of it before it runs away and has to be subjected to a full desalination process, so that it can be directed either into a properly managed aquifer, to (if necessary upgraded) existing water purification works or into wastew- ater treatment works?

Turton also refers to a need for dual reticulation. For coastal cities, and especially for buildings directly alongside the coast, why not reticulate seawater exclusively for carrying sewage?

Cities elsewhere do it – though it does require changes to the wastewater treatment works.

Why not in South African cities?

Andrew ‘Mugsy’ Spiegel