News | February 20, 2008

Nation's First Large-Scale Desalination Plant Delivers Drought-Proof Water Supply


Clearwater, FL — The nation's first large-scale seawater desalination plant is delivering drinking water to more than 2.5 million residents of the Tampa Bay area. It's a timely solution as continued drought is forecast across the southeastern United States.

While parts of Alabama, Georgia and North Carolina are facing exceptional drought conditions, officials in west-central Florida say their residents are benefiting from the nation's first drought-proof drinking water supply, a project pioneered by the area's regional utility, Tampa Bay Water.

"Nearly a decade ago the Tampa Bay region suffered from an extreme drought, just as we are currently, and at that time we explored how we might drought-proof our system so that this didn't have catastrophic consequences," said Jerry Maxwell, General Manager of Tampa Bay Water, "As we did so seawater was a natural place for us to look. We live in Florida, we are on a peninsula, surrounded by seawaters, and even though it hadn't been undertaken on a large-scale, it seemed the natural thing to do."

Cost was the reason the utility had not considered seawater desalination in the past, Maxwell said. But when technology advances brought the cost of desalinated water down significantly, the utility felt the time was right.

The Tampa Bay Seawater Desalination Plant can produce up to 25 million gallons per day of drinking water. The process works like this:

About 44 million gallons of water from a nearby power plant cooling system is diverted to the plant. There, it goes through pretreatment steps to remove algae and other particles. Using reverse osmosis filters, 25 million gallons per day of freshwater is separated from the seawater.

This leaves behind a twice-as salty byproduct that is blended with a large amount of cooling water from the power plant. That dilution is why environmental studies show no measurable salinity change in Tampa Bay related to plant production.

"In the rest of the world they don't always have as high or as strict of standards as it relates to the environment as we do here in the US, so working in a real natural, sensitive ecosystem meant that we had a very high bar to clear in terms of environmental stewardship," said Maxwell.

The plant faced its share of early problems. Officials say the original developer failed to deliver a plant that met specifications. So Tampa Bay Water engaged two companies with worldwide desalination experience to bring the plant up to specifications. They were American Water, and Acciona Agua of Spain.

"I don't think any public utility has the kind of expertise in house that it takes to undertake a project of this magnitude. In our in instance we partnered with American Water and with Acciona because they had both North American and worldwide experience in the construction of water treatment plants," said Maxwell.

While the plant is designed to produce up to 25 million gallons per day, it can be expanded to produce up to 35 million gallons per day in the future. That, Tampa Bay Water officials say, gives them comfort that public water supply will not be an issue during the next drought.

American Water's Don Correll, sees more such projects on the horizon. "Beyond providing a reliable supply of drinking water to the residents of this region and leading the way for other, similar projects across the United States, this plant is an excellent example of what a successful public-private partnership can accomplish," he said.

"We've already had folks from other coastal areas around the United States, in from in fact around the world, come visit us, to visit this site, see what we have been able to accomplish, understand how it works, and we know it is just a matter of time before other s are able replicate what we have done and in fact, improve on it and advance the science of seawater desalination," Maxwell said.

Acciona Agua's Luis Castilla sees the plant as a demonstration to the world that desalination is a practical solution. "I think personally that this plant is one of the most important plants in the world. The success of this plant is going to have far great impact not only in America but also in the rest of the desalination markets in the world," he said.

"As growth and drought continue to strain the public water supply, it's really good to know that we have a safe and sustainable way to harvest water from the sea," said Maxwell.

SOURCE: Tampa Bay Water