The Civil Engineering Contractor January 2019 | Page 31

INSIGHT
plants were built at more-or-less two-
yearly intervals: 2005, 2007, 2009,
and so on.
Greenwald says that what has
fundamentally changed in Israel is
its sources of water: 15 years ago,
77% of its water supply was from
natural sources and today, the per
cent of natural potable water has
fallen to 35%.
“The other big change that has
occurred during the 15 years,
is the management of the system.
Before 2007, that management was
split among various government
departments. Though everybody
knew we needed a big water
infrastructure, each year when it came
to planning the next year’s budget,
there was some other more urgent
priority, another public hospital, or
some new war in the Middle East
— and never enough for the water
sector. There was also the factor that
desalination plant is expensive. In
2007, the interdepartmental (with
civic representation) Israel Water
Authority was founded on PPP
principles, with the result that water
prices jumped.
“This was unpopular, but it was
nonetheless affordable for households
a few years, but as the population
increased, it was no longer adequate.
We realised we could not continue to
use just our natural water sources as
we had in the past to serve a growing
population. We needed more water
and decided to use manufactured
water from two main sources:
reclaimed wastewater and desalinated
water. We started with reclaimed
wastewater because 30 years ago,
desalinated water was extremely
expensive and we couldn’t afford it.
“Almost all the reclaimed water is
used for agriculture, with a little
for industry and suburban gardens.
Today, 20% of the water used in Israel
is reclaimed wastewater. This helped
Israel for a few years but didn’t fully
solve the problem, as the population
keeps growing and you can only use
reclaimed wastewater to the extent
that you have wastewater to cleanse.
So, we looked at desalination and
today, there are five plants in Israel,
all very large facilities of between
90 million m 3 /year to the largest
130 million m 3 /year, and all based
on the Mediterranean. We are
fortunate in Israel that most of our
population lives along this coastline,
making it more economical than
pumping water 200–300km from
the Sea of Galilee. As long as the
population keeps growing, we will
continue to build more and more
factories for seawater desalination,”
says Greenwald. The advantage of this
strategy, he says, is that as there is
more and more desalinated water in
circulation, there will also be more
wastewater to reclaim. The existing
www.civilsonline.co.za
Today, more than 87% of
the wastewater in Israel
is reused, and most
of the water used for
agricultural irrigation is
reclaimed wastewater.
and meant that we could effectively
address the water shortage.”
Greenwald points out that the
cost of desalinated water is largely
dependent on the cost of energy and
Israel was fortunate in that just when
it commenced its desalination drive,
natural gas was found in the country,
and its cost of energy is relatively
cheap. He did not expect the cost of
water to decrease, but nor would it
rise much more.
He notes that this had at times
caused a political problem in
Israel: the various plants were built
by the private sector based on
government commitment to buying
the production, like South Africa’s
renewable energy programme. This
fixed cost meant that the price could
not come down. The downside is
that even if something like climate
change were to bring about increased
rainfall, the infrastructure would still
have to be paid for, so consumers
should not expect the price to fall.
In conclusion, these processes have
led to the fact that today, more than
87% of the wastewater in Israel is
reused, and most of the water used
for agricultural irrigation is reclaimed
wastewater. nn
A water desalination plant on the sea near the northern Israeli town of Hadera, where
water pumped in from the Mediterranean Sea is pushed through rows of multilayered
plastic membranes, emerging 90 minutes later as clean drinking water.
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