Fresh water is becoming a valuable commodity.
The amount of fresh water worldwide is declining at the same
time that the population is exploding-on track to reach 9.39
billion by 2050 from 6.68 billion currently, according to U.S.
Census Bureau estimates.
One way to ensure that there is enough
potable water to accommodate population growth, as well as to
meet industrial and agricultural demand for clean water, is
through water reuse and desalination technologies.
"There is the same amount of water on this
planet as there was at the beginning of time. All water is
reused, but through technology we can speed up Mother Nature's
process," said Zachary Dorsey, a spokesman for the Alexandria,
Va.-based WateReuse Association.
Houston-based water consultant Tom Pankratz,
whose clients includes the International Desalination
Association (IDA) and Global Water Intelligence, said that
demand for such technologies has been growing steadily at about
8 to 10 percent a year globally, "really spiking" in the past
The installed capacity of desalination
plants, which are used not just to purify saltwater but also
brackish water and wastewater, totaled around 46 million cubic
meters (12.15 billion gallons) a day last year, up 8 percent
from 42.6 million cubic meters (11.25 billion gallons) in 2006
and 15.3 percent ahead of 39.9 million cubic meters (10.54
billion gallons) in 2005, Pankratz said. That is expected to
increase 12 percent to 51.5 million cubic meters (13.6 billion
gallons) a day this year and another 13 percent to 58.1 million
cubic meters (15.35 billion gallons) in 2009. By 2015, that
figure is expected to reach 97.5 million cubic meters (25.76
billion gallons) a day.
The increase is being driven by the fact that
traditional sources of water-rivers and even aquifers-are
drying up or being used up, Pankratz said. In addition, there
is an increasing amount of pollutants in both river water and
groundwater from pharmaceuticals and personal care
products-everything from caffeine, steroids, aspirin and
estrogen to a whole gamut of chemicals. "Desalination has
become a solution for that," he said.
And the cost of desalination has come down
considerably through technological improvements, including
more-efficient energy-recovery techniques. Pankratz said that
the typical operating cost is now between $2.25 and $3.75 per
thousand gallons of water, less than half the cost in the
Even with rising commodity prices
(desalination plants contain either high-end stainless,
titanium, copper-based or polyvinyl chloride piping or tubing),
the cost of building desalination plants has come down
significantly, according to Renee Chu, program manager of
environmental technologies at international consultant Frost
& Sullivan, which she attributes to offshore manufacturing
of facilities. "Many of the plants and their components are
made in China," she said.
Currently there are about 12,500 desalination
facilities of varying sizes in 120 different countries, about
60 percent of them in the Middle East, where desalination
accounts for about 70 percent of water supplies, Dorsey
The expected growth of desalination varies
widely, region by region, according to James D. Birkett,
consultant and principal of West Neck Strategies, Nobleboro,
Maine. He said that while much of the United States is dragging
its feet, "international demand is growing like gangbusters,
especially in the Middle East, Southeast Asia and some areas of
The strongest growth has been in Australia.
Already the driest inhabited continent, Australia has been
suffering from extreme drought conditions, Pankratz said. The
first desalination facility was built there in 2007 and there
are five other plants in varying stages of development. "It has
very little to no alternatives to desalination," he said.
The reason that desalination hasn't taken off
in a big way in the United States is that people aren't feeling
the same sense of desperation as those elsewhere in the world,
Birkett said. "We are blessed with a large amount of fresh
water. In our case, demand isn't outstripping water supply, or
at least it hadn't done so until recently. Also, the
environmental requirements to build a facility here are very
stringent. It took Tampa Bay (Fla.) about four years to get
through a permit for a plant there."
That isn't to say there haven't been inroads
made in the United States. Dorsey said that about eight states
have been making major pushes in the water-reuse arena, the
leaders of which are clearly Florida, Texas and California.
"The southwest United States is dealing with an acute water
shortage, so a number of municipalities are looking at multiple
ways of dealing with this water shortage, including
desalination," he said.
In Long Beach, Calif., a new desalination
technology being looked at is an offshoot of the increasingly
popular reverse-osmosis desalination process, Chu said. It is
expected to be even more energy efficient than reverse osmosis,
which is seen as the most energy efficient and cost effective
of the two major desalination processes in use today.
With reverse osmosis, Pankratz said, the
water is pumped through a semi-permeable membrane that is made
of a plastic film that lets water, but no other materials,
through. Piping is usually made from highly
corrosion-resistant, high-performance austenitic stainless
steels or super duplex stainless steels, given that the
desalination environment used to transport the water is highly
aggressive (about twice as corrosive as saltwater). Most new
desalination facilities, other than those in the Middle East or
the Caribbean, where energy is cheaper, use the reverse-osmosis
technology, largely because it is much more energy efficient
than the other major process, thermal desalination, or
With thermal desalination, the water to be
treated is boiled until it produces vapors. When the vapors are
cooled, it produces purer water, although Pankratz noted that
often the water needs to go through the process five or six
times to reach the purity desired. Tubing made of super duplex
stainless, titanium, copper-nickel, aluminum-bronze or
aluminum-nickel is used.
The Long Beach process is a nano filtration
process, also using a membrane, although the membrane has pores
that are larger than typical reverse-osmosis membranes. While
the water needs to go through such a membrane a few times,
Dorsey said the process is expected to use less energy than
typical reverse osmosis.
"I think the growth of desalination will
continue," especially given that many municipalities are coming
to the realization that they have no choice in ensuring a pure
water supply, Pankratz said. In the past, progress was held
back by the fact that people were afraid of desalination. But
now, with the cost coming down and most of the risks having
been identified and mitigated, people are more open to the