Desalinization plant splits environmentalists in central Florida

Published February 1, 2002

For most of the past several years, central Florida has been battling a prolonged drought. With rainfall scarce and water needs growing, freshwater wells have been drying up, lakes and ponds have been transformed to swamps and grasslands, and the Florida underground aquifer has receded further and further from the surface.

As environmentalists have grown increasingly vocal in demanding that something be done, local government has responded. However, in meeting the demands of one particular environmental lobby, local government has incurred the wrath of another.

The solution that has drawn the wrath of a new group of environmentalists is one that holds the promise of creating a near limitless supply of fresh water without the slightest adverse effect on wells, lakes, ponds, streams, and the Florida aquifer. Tampa Bay Water, a local government agency that provides wholesale water to several cities and counties in the Tampa Bay area, has proposed to build a desalinization plant on the shore of Tampa Bay next year, with at least one more plant to be built along the Gulf of Mexico later this decade.

Desalinization well-suited for central Florida

Desalinization technology is not new. However, market factors have generally made desalinization plants overly costly. Freshwater sources are relatively abundant in the Western Hemisphere, and local governments invariably subsidize the extraction of water from nearby lakes, rivers, and aquifers. The world’s largest and most widespread desalinization plants exist in Saudi Arabia and other parts of the Middle East, where potable water is much scarcer.

The proposed Tampa Bay desalinization plant would be the largest such plant in the Western Hemisphere. To create potable water, the plant would take in 44 million gallons of saltwater per day from Tampa Bay. The saltwater would be pumped under great pressure through special membranes that would extract the salt and other minerals from the water.

Of the 44 million gallons taken in each day, 25 million gallons would be converted to potable water, while the remaining 19 millions gallons would absorb the combined salt extract. This 19 million gallons of briny, double-salt water would be diluted with 1.4 billion gallons of water discharged every day from the Tampa Electric Company’s Big Bend power plant.

The end result would raise the salinity of the power plant discharge water from 26.0 parts per thousand, which is consistent with the overall salinity of Tampa Bay, to 26.3 parts per thousand.

“Desalinated seawater is a drought-proof, alternative water supply that can be produced in an environmentally and economically sound manner,” states the Tampa Bay Water position statement.

The Tampa Bay Water proposal makes sense to local government officials. Desalinization technologies have advanced to the point that converting saltwater to freshwater is not substantially more expensive than extracting potable water from nearby rivers and the Florida aquifer. Moreover, government officials have become increasingly sensitive to the calls of local environmentalists to alleviate the effects of periodic droughts.

For a few extra pennies on the dollar, government officials crafted a solution that would provide freshwater without harming the region’s lakes, ponds, rivers, and wells.

Saltwater environmentalists challenge plant

However, just as local officials acted to please one group of environmentalists, a new group has emerged to challenge the desalinization plant.

A group called Save Our Bays Air and Canals (SOBAC) formed for the sole purpose of blocking the proposed desalinization facility. According to SOBAC, Tampa Bay is a fragile marine estuary that may not be able to handle the desalinization plant’s briny discharge.

“It is believed that the flushing of Tampa Bay is too slow and salt build-up will occur, resulting in the destruction of sensitive marine and wetland habitats. It is our opinion that this facility should be built on the Gulf of Mexico where better mixing of the salty water can be achieved,” states the group’s position summary.

Additionally, SOBAC protests that small marine organisms will not be protected from being sucked into the desalinization chamber.

“The intake screens are not the best available technology and are only required from March 15th -October 15th. The rest of the year marine organisms will be killed as they are sucked into the intake,” states the SOBAC summary.

Opponents of the plant suggest that a better alternative, if a desalinization plant must be built, would be to locate the plant in nearby Pinellas County, directly astride the Gulf of Mexico.

“I am rather firm that it ought to be on the other side of the Bay,” in Pinellas County, said Hillsborough County Environmental Protection Commission executive director Roger Stewart. “They are in open saltwater over there. Why put it in an estuary?”

Alternatively, opponents seek to have the plant extend its intake and discharge pipes several miles out into the Gulf of Mexico. “Tampa Bay is too sensitive,” explained Sierra Club organizer Beth Connor.

Economics point to Tampa Bay plant first

Locating the plant in Pinellas County may sound like a good idea on the surface, argue plant supporters, but it would cost much more money to do so, jeopardizing the economic feasibility of the project. Without an economically feasible desalinization plant, the status quo strains on Florida’s freshwater ecosystems would continue.

“The kind of changes in salinity we’re talking about, these creatures encounter on an hourly basis,” said Robin Lewis, president of Lewis Environmental Services. “Creatures that live in the Bay are used to changes in salinity of 3.0 to 5.0 parts per thousand a day,” Lewis said, contrasted with the 0.3 parts per thousand increase that would result from the Tampa Bay Water proposal. Even the most saline-sensitive organisms can tolerate changes far greater than the brine will cause, he said.

Although Tampa Bay Water officials are likely to support an additional plant in Pinellas County later in the decade, they insist they will not budge from their insistence that the Hillsborough County plant be built first.