Utilities look for alternate water sources

As we endure yet another seasonal drought and more restrictions on the use of water, Keys residents are looking to the future for long-term solutions.

The Florida Keys Aqueduct Authority is the Keys’ sole supplier of potable (drinking quality) water, maintaining a flow of fresh water from the mainland through the Big Pipe, or aqueduct, that runs the length of our island chain. An annual average of 20 million gallons per day is piped to FKAA customers throughout the Keys, according to FKAA spokeswoman Colleen Tagle. That amount drops to around 17 million gallons during the dry season.

Since around half of South Florida’s potable water is currently used for irrigation purposes (a little less in the Keys), it makes sense to develop alternate sources to reduce the demand on the Big Pipe – and the mainland wells it draws from.

Drinking water is a precious, limited resource, while alternate sources are readily available. They also help protect our nearshore waters by reusing water that might otherwise be discharged into the ocean or bay.

The three main alternate sources of water are graywater, reclaimed water, and desalinated water. All three are drought-resistant, available 24/7, and are free from restrictions.

The least expensive alternative source is graywater, recycled from sinks, showers, baths, dishwashers and washing machines. In its untreated form, it can be used for irrigation purposes.

Another alternative source is reclaimed water from sewer systems. It even reduces fertilizer use, since some nutrients like nitrogen and phosphorous remain in the reclaimed water. Thanks to subsidies from the South Florida Water Management District, reclaimed water is less expensive than potable water, helping avoid future water rate increases. It is also used for irrigation.

The highest quality alternative water source is seawater or brackish groundwater that has been filtered through a reverse osmosis (called RO) or desalination system. It is suitable for drinking.

Some of FKAA’s biggest customers have already climbed aboard the green train, installing their own water plants that help them save money while reducing their dependence on FKAA water. A recent Keys Sunday article showed how the Keys’ two 18-hole golf courses are doing it. Marathon’s Sombrero Country Club built its own RO plant to keep its greens green, and Key West Golf Course hooked up to KW Resort Utilities, a Stock Island-based plant that recycles graywater for use on its golf course.

Municipalities are also major users of water. Key Colony Beach uses graywater for irrigation, and Ocean Reef’s reverse osmosis system provides potable water. Big resorts like Cheeca Lodge and Hawk’s Cay also have reclaiming systems.

On a much smaller scale, some homeowners and businesses have added cisterns to capture and store rainwater.

The FKAA is also moving ahead with some big water projects in conjunction with the South Florida Water Management District, which has approved $3 million in partial funding. Reclaimed-water systems on Big Coppitt Key (also serving Shark Key, Boca Chica, Geiger Key and Rockland Key) and Duck Key (also serving Conch Key) and RO systems on North Key Largo and Florida City are already being planned, with future projects being considered for Cudjoe and Summerland keys.

The FKAA already uses some RO, or desalinated water. During the dry season, from Dec. 1 to May 1, about 5 percent of Keys water comes from the brackish Floridan Aquifer. The rest comes from the freshwater Biscayne Aquifer. The $30 million Florida City desalination project, scheduled to be completed by 2010, will decrease the demand on the Biscayne Aquifer by treating up to an additional six million gallons of brackish water per day. That means that someday 40 percent of our potable water will come from the new plant.

The FKAA also maintains RO plants in Stock Island (processing 2 million gallons a day) and Marathon (1 million gallons a day).

According to the FKAA’s Tagle, the Florida City plant will save additional money by tapping into the Turkey Point power plant for its energy.

Water drinkers may be surprised to learn that our tap water — and the future output of the new plant — is higher in quality than most bottled water. “Federal drinking water standards are higher for tap than bottled,” she says. “We have been handing out bottled tap water at various community events, and will continue to bottle water from the new plant.”

The FKAA hopes to get federal money to pay for a significant portion of the Florida City project. The FKAA is part of a group of water agencies throughout the country, known as the New Water Coalition, which lobbies Congress for desalination project funding.

The FKAA is already laying new sewer pipes in neighborhoods throughout the Keys, to help convert the islands from septic tank-based systems to modern Advanced Waste Treatment (AWT) methods, driven by a state mandate and a 2010 deadline. In some areas, such as along Marathon’s Sombrero Beach Road, an additional pipe – colored purple to differentiate it from the others — is being laid down to handle water reclaimed from the new sewage systems. The Purple Pipe will carry irrigation water to local parks and other properties and someday may be offered to homeowners as the supply increases.