Last week, WQP, Water & Wastes Digest (W&WD), and Storm Water Solutions (SWS) editors traveled to Houston to speak with water...
The Tampa Bay area's nearly 2 million residents have begun tapping a new source for their drinking water the salty bay water.
The nation's first sea water desalination plant built to serve as a primary source of drinking water now is providing water to Tampa, St. Petersburg, New Port Richey and surrounding cities in Florida.
The initial output is between 8 million to 12 million gallons a day, but the plant is expected to reach full capacity by mid-April, generating 25 million gallons a day. That's 10 percent of the area's drinking water.
The plant has become operational despite concerns from some area residents that it will increase salinity in Tampa Bay and reduce oxygen in the water.
In the basic process of desalination, salt water is pumped through filters under high pressure, squeezing out minerals. Israel and Kuwait have relied on desalination for decades, as have military vessels and cruise ships.
Worldwide, 13,600 desalination plants produce 6.8 billion gallons of water daily.
The Tampa Bay Seawater Desalination Plant, run by Tampa Bay Water, is expected to convert sea water efficiently enough to be able to sell it for about $2 per 1,000 gallons, far below the industry standard. The cost of regular groundwater sources is about $1 per 1,000 gallons, Ken Herd, project manager for Tampa Bay Water, told The Associated Press.
It cost $110 million to build the plant as well as the 14-mile pipe to transport the water. The Southwest Florida Water Management District gave Tampa Bay Water $85 million to help defray the costs. In addition, the plant will use the 44 million gallons a day used by Tampa Electric's Big Bend Power Station, further lowering costs.
The 44 million gallons of sea water undergoes reverse osmosis, where it is pushed through a series of filters before passing through membranes, leaving 25 millions of gallons of fresh water and 19 million gallons of brine.
The pure water is treated with lime and chlorine to ensure proper alkalinity, Herd said.
The highly salty byproduct will flow into the Big Bend power plant's cooling water canal, where it will be diluted in the 1.4 billion gallons the canal carries each day.
It is this byproduct that has caused the most concern for some area residents, although Luther led a study in 2000 that found the briny waste would not cause any long-term increases in salinity.
Apollo Beach residents formed Save Our Bays, Air and Canals and fought to have the permits to the plant denied, and eventually sued the Florida Department of Environmental Protection to contest the state permit for the plant. It lost that bid, but group attorney Ralf Brookes said they will monitor the area for any environmental problems.
Other environmental groups, including the Audubon Society and Sierra Club, have said they have not seen any data that shows the fears are founded, and are waiting to see the results of a $1 million monitoring program. Herd said that it's too early to see any changes in the bay, since the initial output just began in mid-March.
The state permit requires that the plant conduct several types of monitoring on a daily, weekly and quarterly basis. Also, state officials will do inspections at least once a year. The plant's permit is good for five years, but can be revoked earlier.
Key West, Florida, has had a desalination plant for years, and one was built in Santa Barbara, Calif., in 1992. Both are much smaller, and are used only for emergency supplies.
In December, the prime minister of Singapore came to study the plant on the edge of Tampa Bay. Communities from Mexico, Iceland, Texas, California and Florida's east coast also have shown interest.