Appomattox wastewater problems may have solution

By Sarah Watson

Published: October 25, 2008

Simple chemistry may be the solution to lowering copper levels in water discharged from one of the town of Appomattox’s wastewater treatment plants.

Town officials recently experimented with putting different amounts of magnesium hydroxide into water coming into the trickling filter plant. They discovered that the addition made the copper in the water less toxic to the aquatic life living in a stream in which the plant discharges, town manager David Garrett said.

“If the copper is not harmful, then it’s not a problem,” he said.

The town is under a Department of Environmental Quality order to lower the already tiny amounts further to meet state and federal clean water requirements.

Town officials learned of the possible solution after talking with water managers in Nelson County, where a similar problem was impacting the Wintergreen area, Garrett said.

If successful, the approach could translate into significant savings for the county, which has had other more-costly measures under consideration to meet the DEQ mandate.

The copper, which does not pose a danger to people, is the result of naturally acidic well water flowing through miles of copper pipes in town buildings. As the water flows through the pipes, it causes tiny amounts of copper to leach out. The amount is magnified when the water reaches the wastewater treatment plant, Garrett said. Too much copper can harm certain sensitive aquatic organisms, such as trout.

Town council approved an action plan with the new solution earlier this month. Also included as potential measures were conducting a stream analysis to see how many copper-sensitive organisms live in Caldwell Creek, changing the town’s water source or installing an expensive electro-coagulation device that removes metals from the water.

The plan was sent to DEQ last week and is under review, Garrett said. “The plan may not necessarily be approved by DEQ, but the council approved it,” he said.

Cost-wise, using the simple chemical addition would be significantly less expensive than most other options on the table, Garrett said. He estimated the treatment would add $16,000 to the town’s annual chemical bill. The electro-coagulation program could cost $750,000 initially and $40,000 per year.

The Town of Appomattox has been dealing with the copper issue for several years after the discharge permit for the affected plant was renewed in 2004. Copper levels in discharged water were about 200 parts per billion, but the new permit required levels to be less than 21 parts per billion.

New DEQ limits were imposed because of tightening restrictions and because the stream that the plant discharged in is small and therefore unable to dilute the amount as much as a larger water body.

A series of actions over the years gradually brought the level down to near the limit, but it’s been difficult to consistently break that 21 parts-per-billion barrier, Garrett said. But after the addition of the chemical, “we noticed that the hardness level has increased, which makes the copper not toxic,” Garrett said.

“It’s helping a lot of other things, which is keeping the pH at a level where things work more efficiently.”