Water plant’s expansion almost done

Published 10:46 pm Friday, April 10, 2009

For months, crews have been working to finish an expansion on the G. Robert House Water Treatment Plant in Chuckatuck.

The work, which includes new water treatment equipment, generators, fuel storage tanks, chemical storage and other facilities, all will help increase the capacity of the plant, which converts groundwater and surface water into water usable for drinking, cooking, bathing and other daily activities of Suffolk residents. It supplies the water for most of Suffolk north of U.S. Route 58.

When completed later this year, the plant will be the largest municipal water-treatment facility in the country that uses EDR – electrodialysis reversal – to cleanse its water. EDR uses an electrochemical separation process to remove ions and other charged particles, especially fluoride, from water. The $44 million expansion will nearly double the plant’s daily groundwater treatment capacity.

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The need for backup electrical power became evident during the aftermath of Hurricane Isabel, when the plant had to run for five days on backup generators. The extra capacity, which should last through at least 2015, is needed for the anticipated population growth in Suffolk.

The plant currently has six EDR units, which are being supplemented by five extra units added in the expansion. Each unit can process about 1.25 million gallons of water per day, according to Craig Ziesemer, assistant director of public utilities for Suffolk.

The units remove the majority of fluoride – the main undesirable component of Suffolk’s groundwater – from the water that is pumped by three wells. In addition, some of the hardness, alkalinity and calcium also come out of the water during the process, and chlorine is added to comply with state regulations.

The plant also processes surface water, although not nearly as much as groundwater. For surface water, which is held in “lagoons” behind the plant, workers drop “flock,” which is a sawdust-like material, into the water, which traps particles on its way to the bottom. Once the flock has settled to the bottom, the water is pumped out, and the sludge on the bottom is bulldozed out and carted to the landfill.

Excess fluoride that is pulled from the water is discharged into the Nansemond River. The amount of fluoride shouldn’t be enough to harm the river, Ziesemer said.

After the water is treated, it is moved to one of two 3-million-gallon storage tanks, one of which is part of the expansion. The storage tanks help accommodate use in the early-morning hours, when demand is the highest because of people taking showers, brushing teeth and getting ready for the day, Ziesemer said.

“The demand drops off later in the day,” Ziesemer said.

Demand also is high on hot summer days when it hasn’t rained for a while, he said, because of people watering their lawns and filling swimming pools.

“When it rains, people don’t need that much water,” Ziesemer said.

Before it leaves the plant, a sample of water is tested in the facility’s laboratory, to ensure the amounts of fluoride and other chemicals are appropriate. Suffolk’s groundwater typically has 4 to 6 times more fluoride than permitted in drinking water, so the testing process ensures that enough fluoride has been eliminated for the water to be potable.

A ribbon cutting for the expansion is anticipated for June.