THE VIRGINIAN-PILOT
Copyright (c) 1994, Landmark Communications, Inc.
DATE: Wednesday, July 13, 1994 TAG: 9407130423
SECTION: LOCAL PAGE: B1 EDITION: FINAL
SOURCE: BY JEFF HOOTEN, STAFF WRITER
DATELINE: CHESAPEAKE LENGTH: Long : 102 lines
In this city, where water quality ebbs and flows with the wind, they have finally put a price on good taste: $8.7 million.
That's what they're spending for an upgrade at the Northwest River Water Treatment Plant that officials say will eliminate Chesapeake's salty-water woes.
The new system, which desalinates as it purifies, was approved Tuesday night by City Council.
It should put an end to the scramble for bottled water whenever the tap supply gets foul.
More important, city officials say, it will allow Chesapeake to meet stringent federal water standards that go into effect in June 1998.
No immediate rate increases were proposed, but utility officials said the new system could eventually cost the average resident about $6 a month in higher water bills - a 30 percent increase that is about the price of nine gallon jugs of water at the supermarket.
The upgrade uses a process called nanofiltration, in which water is forced through a tightly wound synthetic material. The holes in this membrane are so small that impurities and even dissolved salt molecules can't get through, said Public Utilities Director Amar Dwarkanath.
He said the city would have to go to such a process anyway for its plant to meet the 1998 Safe Drinking Water Act.
``If you are going to use the membrane process,'' he said, ``you might as well extend the technology to the saltwater problem, so you get two for the price of one.''
Council voted to redirect $6.1 million already set aside for previous water treatment projects and agreed to spend an additional $2.6 million for the work.
It resolved to raise that money by selling revenue bonds in 1995.
For the city to get as much water as it now produces, the upgrade will require tapping four wells about 1,300 feet deep.
The problem with using membrane technology, Dwarkanath said, is that 30 percent of the city's already-limited supply will be wasted in the brine created by the process.
That leaves only 7 million gallons of the 10 million now produced daily by the Northwest River plant.
To keep the flow steady, the city will dig four wells near the Northwest River plant. These are to provide an additional 5 million gallons a day, Dwarkanath said, which, after treatment, would return the total daily output to 10 million gallons.
The city already has draft permits for those wells, City Council was told Tuesday. It also has applied for permission to dump the wastewater brine into the Elizabeth River, one of the most polluted waterways in America.
City officials expect final approval on both permits within 90 days.
Since the mid-1980s, Chesapeake has been looking for solutions to its problem of salty water.
Emergency wells were drilled in the Western Branch area, and officials suggested treating water from the Dismal Swamp at a proposed plant in Deep Creek.
That plan was shelved when the Ground Water Management Act of 1992 made it possible to get state permits for new wells for the first time in at least a decade.
``The cost of treating Dismal Swamp water was extremely high,'' Dwarkanath said. ``Even with that, we still would've had to improve the Northwest River plant to meet the Safe Drinking Water Act. So why spend the money?''
Although ocean desalinization is considered too expensive a solution for the area's growing water shortage, it can work as a stopgap in Chesapeake, Dwarkanath said.
``Brackish water is different from sea water. It has much less dissolved solids, so it can be treated under lower pressure,'' Dwarkanath said.
``Sea water requires higher pressure and a tighter membrane, which translates into higher costs.''
Chesapeake uses about 13 million gallons of water a day. The city covers its shortfall by buying water from Portsmouth and Norfolk. Dwarkanath said that both cities recently increased the rate they charge Chesapeake - Norfolk by 12 percent and Portsmouth by 5 percent.
Dwarkanath said that to meet the 1998 federal regulations construction would need to begin next year.
``That's when a rate increase would likely take effect,'' he said.
Dwarkanath acknowledged that adding nanofiltration to the Northwest River plant will not increase Chesapeake's current water supply.
``A long-term solution for us is still Lake Gaston, combined with additional water from neighboring cities,'' he said. ILLUSTRATION: Graphic
JOHN CASERTA, JOHN EARLE/Staff
THE STEPS OF THE SYSTEM
by CNB