Water, Sewage & Effluent November December 2018 | Page 35

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Sand purification
Sand and gravel have been
used to purify water for
thousands of years, and in
1804, a Scotsman named
John Gibb designed and built
the first filter that strained
water through grains of
sand to remove bigger
particles of contamination.
But recently, researchers
have figured out how to coat
sand grains with graphite
oxide to create ‘super sand’
that reportedly can filter
harmful substances such as
mercury from water five times
as effectively as ordinary
sand. Work continues to
find ways to make super
sand absorb even more
contamination and eventually
use it in developing countries
where water supplies are
dangerously polluted.
Sand, long used for filtration, is about to be boosted into ‘super sand’.
The Atlas uses the best-available data to create high-resolution, customisable global maps
of water risk. (Image for illustrative purposes.)
www.waterafrica.co.za
Water Sewage & Effluent November/December 2018
33
innovations
Aqueduct's global water risk mapping
tool helps companies, investors,
governments, and other users
understand where and how water
risks and opportunities are emerging
worldwide. The Atlas uses a robust,
peer-reviewed methodology and the
best-available data to create high-
resolution, customisable global maps
of water risk.
Water scarcity is one of the defining
issues of the 21st century. In its Global
Risks 2013 report, the World Economic
Forum identified water supply crises
as one of the highest impacts and
most-likely risks facing the planet.
With the support of a diverse group
of partners, the World Resources
Institute built Aqueduct to help
companies, investors, governments,
and communities better understand
where and how water risks are
emerging around the world.
Aqueduct water risk atlas
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