Thirsty Harford city may tap bay

Aberdeen considers investing $14 million for desalinization

July 07, 2006|By MARY GAIL HARE | MARY GAIL HARE,SUN REPORTER

Short on water and facing significant population growth on the horizon, Aberdeen is considering tapping a bountiful source in its backyard: the Chesapeake Bay.

A proposal to build a plant that would extract salt from the brackish waters of the bay would make the Harford County community the first in Maryland to desalinate water for human consumption, implementing a process used in other parts of the world but not widely in the United States.

The city proposes to withdraw as much as 6 million gallons a day from the bay - the nation's largest estuary - and treat it at an Aberdeen Proving Ground pumping station that has been unused since about 1998.

The station would be retooled for about $14 million, and the base would continue to get drinking water from the city system.

"We are close to a limitless source," said Mayor S. Fred Simmons. "We have a plant we can renovate and get on line within four years. And it is behind a super-secret fence on an Army base, virtually impossible to contaminate."

Current needs are straining the city's well-based water supply, and more demand is coming. With thousands of new workers expected to arrive at APG as a result of the federal base realignment and closure plan, Aberdeen is working to annex nearly 1,000 acres of farmland to make way for development that could double its population of 14,000.

"Aberdeen lacks water capacity now, and this bay water treatment plant would have to be completed before it can develop further," said Jacqueline K. Ludwig, chief of administration and engineering for Harford's department of public works. "They have to have a plan before their water runs out."

Desalinization is a technique many communities will be compelled to consider in coming years, said M. Gordon "Reds" Wolman, chairman of the Maryland Department of the Environment's water resources advisory committee.

"If we think about the future, we may have to go to the bay," said Wolman, also a professor of geography at the Johns Hopkins University.

The city plans to drill a 24-foot-deep collector well on land at Plum Point. Underground lateral intake pipes would fan out from the well into the bay bottom at Plum Point, a tidal portion of the bay that is mostly water from the Susquehanna River, said J. Kenneth Benner, Aberdeen's water superintendent.

Water would be taken from the bay to a 10,000-square-foot building that would be retrofitted with desalinization equipment. Water exceeding the federal saline limit of 250 milligrams per liter would be run through ultrafine filtration equipment in a process known as reverse osmosis.

High-velocity flow puts pressure on brackish water on one side of the filter, which pulls the salt from the water as it flows into an adjoining filter.

"You are talking about equipment that can filter out everything, even dissolved material," Brenner said. "It works. We could have the best water quality in the state."

The treated water would be pumped to thousands of homes and businesses on the base and throughout the city. Officials said they expect the withdrawal and treatment of the water to have no effect on the salinity of the bay.

Countries around the world have turned to desalinization technology to solve water dilemmas. Desert nations in the Middle East have used it for 30 years, making sea water potable and turning sand dunes into agricultural land, said Yoram Cohen, director of the UCLA Water Technology Resource Center and a desalination expert.

Major plants are being built in Singapore, Australia and Spain, and Israel recently opened one of the world's largest, Cohen said.

One factor slowing the technology's spread is the cost: mostly the energy required to power the high-velocity water flow for the reverse osmosis process.

"It is just more expensive at the moment," said Wolman.

However, Aberdeen has an advantage in one regard. Higher-salinity water costs more to treat, but the water off Plum Point is of relatively low salinity. In fact, many experts say desalinization would be needed only a few months of the year.

"Basically, that far north, you could classify it as almost fresh water for about nine months of the year," said Chuck Gates, a spokesman for the Maryland Department of the Environment, which gave the city the OK to proceed with preliminary testing.

Besides, energy costs can be viewed as relative, he said: "Desalinization expense is in energy costs, but it is more cost-effective than building a big pipeline to the Susquehanna."

Since 1998, Newport News, Va., has operated a desalinization plant that serves five municipalities. The $17 million plant treats up to 7 million gallons daily, 5 million of which is drinkable and is blended with water from other sources. The 2 million gallons left over from the treatment process is released into the James River.

Though the source differs from what Aberdeen is considering - Newport News draws water from underground reservoirs - the salinity level is comparable.

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