Drought and growth prompt more cities to quench thirst with salt water

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Walk around California’s Catalina Island and you see plenty of water – sometimes water as far as the eye can see. But the island is one of those hardest hit by the extreme drought that is plaguing the state.

A mandatory 25% reduction in water use wasn’t enough. Faced with a looming 50% mandatory reduction, the island decided instead to look for another source of water. It found it through desalination.

Rapid solution to critical shortage
Council Lead Partner GE was able to help the island dramatically expand its desalination capabilities in just one month. Desalination equipment began arriving on the island a few weeks ago; the new capacity comes online later this month.

This rapid response was critical for the island where tourists vastly outnumber residents. The island's population is about 4,000 residents, but it welcomes 700,000 visitors each year. Anything that hurts tourism hurts the residents.

Much of the island’s potable water comes from wells and an existing desalination facility. The solution from GE nearly doubles that facility’s capacity to produce 350,000 gallons of water per day, which should be enough to prevent any further mandatory water reductions.

Other California cities exploring it
There’s no end in sight to California’s drought, which is prompting other cities to look at desalination as well. But, for them, the answer can be much more murky.

Antioch has rights to pump the water it needs from the San Joaquin River, but the salinity of that water varies. A desalination plant would allow it to make use of that water, but the environmental impact and water rights analysis alone would cost $6 million.

It hired a consultant to take an initial look at feasibility, but so far has found that residents were able to curtail their water use even more than the state requires.

Salt water can be significant source
While some cities are looking at desalination as a way to stretch scarce water supplies during a severe drought, others are now looking at it as their primary source. One of those is the city-state of Singapore.

After bringing two desalination plants online with the help of Council Associate Partner Black & Veatch, Singapore now gets about 25% of its potable water from the ocean. But that’s just the tip of the iceberg for the city of 5.4 million. By 2060, the city plans to get half of that water from desalination and other alternative sources.

In Australia, Council Associate Partner CH2M designed and helped supervise the construction of a desalination plant to meet the water needs of Queensland’s growing population. Other desalination facilities in the country had been used on a temporary basis to make up for water shortages at times of peak consumption, but now the country is talking about making them permanent sources of clean water.

Desalination breaks mining bottleneck
In Chile, a lack of water has been the bottleneck that has prevented the country from expanding its mining operations. Council Lead Partner Bechtel is providing engineering, project management and construction services for what will become Chile’s largest desalination plant, one of 16 such projects in the country.

A lack of water is the only thing holding back copper production at the Escondida mine. And while work on the new desalination plant began in July 2013, it won’t be capable of meeting the mine’s needs until 2018.

For Chile, the project will help boost the economy by allowing its mining industry to grow and free scarce freshwater for drinking and other purposes.

New technology improves efficiency
Aside from environmental reviews and permits, one of the biggest barriers to desalination is the amount of energy needed to run the facilities. Council Associate Partner Veolia is working on a pilot project to reduce those energy needs.

Four small desalination facilities will be online by October in Ghantoot on the Persian Gulf coast between Abu Dhabi and Dubai. Together, they will produce only 1,530 cubic meters of clean water per day – not even 1% of the volume of the nearby Dubai Fountain lake. But managers will carefully evaluate the energy use at each plant in hopes of finding ways to minimize the energy needed to move water through the various membranes.

The entire pilot project will last for 18 months. During the final six months of the project, managers of each site will be trying different approaches to further optimize their energy use.

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Kevin Ebi is a staff writer and social media coordinator for the Council. Follow @smartccouncil on Twitter.

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This article is from the Council's Compassionate Cities initiative which highlights how city leaders and other stakeholders can leverage smart technologies to end suffering in their communities and give all citizens a route out of poverty. Click the Compassionate Cities box on our registration page to receive our weekly newsletter.

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