The world’s unquenchable thirst for clean water drove a record increase in the desalination of seawater and reuse of sewage last year, new figures reveal, as water-stressed countries around the world try to build their way out of trouble.

Making fresh water from the sea was once the preserve of cruise ships and oil-rich Gulf states that could afford the huge cost of energy required to remove the salt. But as rivers, lakes and aquifers dry up, rains become less reliable, and the cost of desalination has fallen, communities in all parts of the world have begun to build and plan plants to turn oceans, river estuaries, salty ground water and even sewage into clean water for factories, farms and homes.

The rise in fresh water production was the biggest ever recorded at 9,5-million cubic meters a day, the annual report by analysts Global Water Intelligence will say on Wednesday. That is equivalent to about 10% of global capacity.

Those desalinating and reusing water now include some of the world’s poorest countries, including Algeria, Chenai in India and Ghana; wet but over-populated cities like London and Dublin; and those far from the sea, most notably a plan by the United States state of Nevada to build a desalination plant in Mexico in return for keeping a greater share of the Colorado River.

Rivers flowing backwards
With water “manufacturing” technology allowing people to change fundamentally the geography of freshwater on such a large scale, Christopher Gasson, GWI’s publisher, talks of “rivers flowing backwards”.

“People do desalination when they run out of opportunities, and the problem is the world overall is running out of opportunities: groundwater is over-exploited to the extent it’s becoming saline and unusable; rivers are being drained; new dams are becoming less and less viable [and] long-distance transfer is expensive and controversial,” said Gasson.

“People are being forced to look to non-traditional alternatives for water supply. For coastal people desalination is the obvious one; if you’re inland then there may be some brackish water underground you could desalinate, or you might need to look at reuse.”

The fundamental reason for the rise of water manufacturing is a simple gap between demand and supply: in 2006 a report from the International Water Management Institute found one-in-three people in the world were “enduring one form or another of water scarcity” — such as “when women work hard to get water, [or] you want to allocate more but can’t”.

Growing numbers of people; richer lifestyles; demand for more water-intensive food such as meat, and dwindling supplies are expected to increase that number — to up to half the projected global population or more in the middle of this century.
And that is despite an expected doubling of total water manufacturing capacity between now and 2016, according to UK-based GWI.

The falling cost of desalination, thanks to technology improvements is key, and the reuse of water can be cheaper still.

Developments in membranes
Contacts have been signed to deliver desalinated water in Algeria and Israel for 55-56 cents per cubic metre, and reuse plants can now turn sewage into drinking water for between 40 and 45c per cubic metre, said Gasson.

Comparisons between the energy needs of different desalination methods — heating up water for distillation or pushing it through membranes to filter the salt — have also become much closer. Continuing developments in membranes — which one day are likely to be modelled on the “technology” nature uses in kidneys and mangroves — will continue to bring down costs and energy needs, said Gasson.

Systems using carbon-free energy are also being trialled: nuclear desalination in the United Arab Emirates, solar power in Australia, and biodiesel from plants — with cooking fats also slated as a future possibility — at a desalination plant built by Thames Water in London.

Despite the advances, there are still serious objections to manufacturing water. The WWF remains concerned about building new facilities in often environmentally-sensitive coastal and wetland areas; about the intake of seawater which is home to millions of tiny species, and discharge of the remaining brine, which can be contaminated with chemicals from cleaning the membranes and particles from corroding pipes.

Concerns about the energy use of plants also still remain, especially where they are still dependent on fossil fuels, or if they could divert renewable resources which could otherwise replace existing carbon-intensive energy supplies. Residents in upmarket Monterey, California have long objected to a desalination plant being built there because they fear it would encourage more development.

Barrier of cost
The Namibian capital Windhoek is unusual in that it pumps recycled sewage directly back into the public drinking supply, whereas every other water reuse project in the world — from Salt Lake City to Singapore — adds unnecessary cost by using the recycled water only for irrigation or industry, or pumping it into reservoirs, aquifers or rivers, and then pumping it back out and cleaning it again, in order to avoid a public outcry.

Instead, critics prefer a combination of dozens of small improvements to existing pipes and irrigation channels, switching to less thirsty crops and other measures to save water. This approach was recently backed by a major report from the 2030 Water Resources Group, an alliance of mostly private companies with huge water needs, including Coca-Cola and brewers SAB Miller, and the World Bank group.

And there remains the barrier of cost. Desalination and reuse might be getting cheaper, but prices are still unaffordable for millions of farmers worldwide who have long relied on “free’”water, said Gasson: “There’s no solution to the over-exploitation of natural water resources in agriculture. Full-stop.”

Namibia: toilet to tap
The capital Windhoek, surrounded by desert, has the world’s only system that treats wastewater and putts it straight back into the public water supply system, mixed with water from the city’s main reservoir. The success of the scheme is credited to a long-standing public acceptance campaign, including advertising, education in schools and an “excellent” water-quality record.

Arizona and Nevada, US: Desert desalination
US states and Mexico share the Colorado river under a treaty signed in 1922. Now it is suggested Nevada funds a desalination plant in Mexico or California in return for more of their river water. In Arizona they have discussed reopening a mothballed desalination plant to process farmland runoff and pump it back into the river.

UK: Desperate measures in the capital
Despite its rainy reputation London receives less rainfall than Rome, Dallas or Istanbul. To cope with an expected 800 000 more residents by 2016, and more water-hungry appliances like power showers, Thames Water, the capital’s water company, has built a desalination plant next to its Becton sewage works, which it says will help cope with peak demands.

Jordan: Simple, cheaper solutions

Jordan is one of the most water-stressed nations on Earth, and one of the poorest. There is talk of a desalination plant and mega water transfer across the country. For now, though, the focus is on improving irrigation, collecting rainwater in cisterns and small dams, replacing water-hungry crops with food suited to an arid climate, and researching wastewater reuse for irrigation. – guardian.co.uk © Guardian News and Media 2010

Solar Quotes

Green is good — right? Not necessarily when it comes to lawns, according to a new study by UCI researchers. For the first time, scientists compared the amount of greenhouse gases stored by ornamental turfgrass to the amount emitted in the irrigation, fertilizing and mowing of the same plots.

In four parks near Irvine, they calculated that emissions were similar to or greater than the amount of carbon dioxide stored through photosynthesis — a finding relevant to policymakers seeking to control the gases that trap heat in the atmosphere and contribute to climate change. “Green spaces may be good to have,” said geochemist AmyTownsend-Small, the lead researcher in the paper published in the journal Geophysical Research Letters. “But they shouldn’t be automatically counted as sequestering carbon.”

The paper is particularly timely, she added, because governments are calculating their carbon footprints, and discussing whether parkland could offset other sources of emissions, such as refineries, power plants and automobiles. Turfgrass covers about 1.9% of the U.S. and is the most commonly irrigated crop. It is increasingly in demand in urban areas.

Townsend-Small and colleague Claudia Czimczik measured the carbon stored in the parks’ soil samples, and compared that with emissions from producing fertilizer, from mowing with gasoline-powered equipment and from pumping water to irrigate the plots. The pumped water was recycled — but if it were fresh water transported from the Colorado River, as is much of Southern California water, emissions would be higher, said Townsend-Small. They also factored in the nitrous oxide released from soil after fertilization. Nitrous oxide is a greenhouse gas 300 times more powerful than carbon dioxide, which is released by fossil fuel combustion.

California has no regulations to control turfgrass, but the study “shows the importance of full life-cycle analysis for greenhouse gases,” said Mary Nichols, head of the California Air Resources Board, which is charged with reducing the state’s carbon footprint. Research is underway, she noted, to develop varieties of grass that need less mowing and use less water.

What about the heat island effect, the vaunted benefit of plants as a way to cool cities? “Irrigating trees in urban Southern California reduces the heat island effect,” said Stephanie Pincetl, author of “Transforming California: A Political History of Land Use and Development.” “But lawns have no such benefits, and also contribute to water pollution because they are heavily fertilized.”
Townsend-Small said that turf emissions vary according to region. Studies would need to be done in wetter northern climates. There, she said, grass might not need irrigation, but it would also store less carbon during cold winter months.

For Southern California residential lawns, she noted, using rakes rather than leaf-blowers and hand mowers rather than gasoline-powered equipment would improve their carbon footprint.

“About 40% of the drinking water we import at great financial and environmental expense is used for outdoor irrigation,” said Paula Daniels, an L.A. Department of Public Works commissioner. “This study hopefully will motivate more of us to make changes in our landscapes.”

–Margot Roosevelt

ISSUED BY: THE DEPARTMENT OF WATER AFFAIRS
DATE: 20 January 2010
DROUGHT CONDITIONS PERSIST
The Department of Water Affairs has prioritized support for parts of the
country affected by the prevailing drought conditions due to low rainfall during
last year (2009). According to statistics gathered by the Department, George in
the Eden District Municipality in the Western Cape experienced the lowest 12
consecutive months of rainfall since 1921 and is considered severely dry. The
current conditions started around the month of March 2008.
Having received an annual rainfall of 477mm in the last year which accounts for
only 63 percent of the areas Mean Annual Precipitation (the average amount of
rainfall received annually), urgent measures had to be put in place to deal with
the water shortages including the introduction of severe water restrictions,
sewage water is being re-directed to the purification plants and sea water is
being desalinated to augment supply.
In addition the water storage levels for this area are well below average and
are declining further. The Garden Route Dam: Storage is 30% which is 70%
below the median storage. The Wolwedans Dam: Storage is 37.1% which is 60%
below the median storage and also gradually declining.
Certain parts of the Eastern Cape are under severe pressure and are also
experiencing severe drought conditions; these include Uitenhage under the
Cacadu district municipality, which received a total rainfall of 360mm from
January to December 2009, accounting for only 69 % of its average annual
rainfall. Other affected areas are Grahamstown and Somerset East (Cacadu
District Municipality), Kei Mouth (OR Tambo District Municipality) and Hogsback
(Chris Hani District Municipality) as well as Phalaborwa in the Limpopo
province.
Mava Scott, spokesperson for the department says the Minister’s visit to areas
like Adelaide and Kuruman this week was part of a nationwide drive to find
creative solutions and interventions in the short to long term provision of water
to these communities. “these interventions include soliciting funds to
commission drilling for water/boreholes in the short term, recycling of sewage
water in the medium term but also very importantly the upgrading of the
existing water schemes” he said.
The delivery of water tankers to villages who experienced severe water
shortages in December in the Zeerust area by the Minister constituted one of
these measures to respond urgently to the drought conditions.
Also of critical importance was the issue of water conservation and demand
management especially in these drought stricken areas. Mr Scott added that
consumer behavior in the use of water can go a long way in addressing the
issue of water provision to the communities.
During the 2009 year most parts of the country received normal to above-normal
rainfall with the exception of the southern parts of the Western and Eastern Cape
Provinces, the western parts on the North West Province, the south-eastern parts of
the Limpopo Province and small areas over northern KZN.
The Department of Water Affairs is closely monitoring the situation. Interventions are
being implemented and finalized in other areas. Water Conservation and Demand
management initiatives have been ongoing and these will be intensified.