Mount Pleasant Waterworks wants to partner with a federal agency to study whether the utility's planned $70 million wastewater treatment technology will keep pharmaceuticals harmful to wildlife out of Charleston Harbor, General Manager Clay Duffie said Wednesday.
The utility would be the first in the tri-county area to have the new treatment method, which is scheduled to come online in 2011, Duffie said.
In a recently reported study, researchers found that nearly two-thirds of 23 dolphin tested in the waters around Charleston Harbor, Wando and Stono rivers carried antibiotic-resistant bacteria thought to be a result of antibiotics flushed into area waters.
Studies have shown that antibiotics don't break down in conventional wastewater treatment, and antibiotic-resistant bacteria have been found near treatment plants.
However, there is research to show that the membrane filtering system that Mount Pleasant Waterworks plans to bring to the area is effective at removing antibiotics and other drugs from wastewater, Duffie said.
Geoff Scott, director of the National Ocean Service Center for Coastal Environmental Health and Biomolecular Research at Fort Johnson, said the agency would like to partner with Mount Pleasant Waterworks to study the effectiveness of the new treatment method. "We would be more than interested in that," Scott said.
Mount Pleasant Waterworks on average discharges 6.6 million gallons of treated wastewater daily into the harbor. The proposed study would measure levels of prescription drugs in wastewater after it is treated using the new technology, Duffie said. The system will use a more high-tech system of membrane filters and ultraviolet light.
The new way of cleaning wastewater does not use chlorine, which means residual amounts of the toxic gas aren't flushed into the harbor with treated wastewater, he said. Having large tanks of chlorine gas on site also is an issue with the U.S. Department of Homeland Security because of its potential use in a terrorist attack, he said.
The treatment upgrade will mean the Rifle Range Road plant in theory will produce wastewater so clean that it could be used for irrigation, said William Golightly, Mount Pleasant Waterworks Commission chairman.
Running irrigation lines is cost-prohibitive in areas that already are developed, but the treated wastewater could be injected into the aquifer where the town draws its water to reduce the threat of saltwater intrusion, Golightly said.
However, injecting the treated wastewater into the aquifer does not mean it would then be drawn from the ground for drinking, he said.
The wastewater treatment improvements are projected to mean about a 7 percent increase in water bills per year for three successive years. "We're not certain about that because staff is still working on the budget," Duffie said.
As part of the upgrade, Mount Pleasant Waterworks would close its aged Center Street plant, which is licensed for a maximum wastewater processing capacity of 3.7 million gallons per day. That capacity would be shifted to the Rifle Range Road plant, which is authorized to handle up to 6 million gallons of wastewater daily.
A proposal to increase the maximum capacity of the Rifle Range Road plant from 6 million gallons daily to 10 million gallons daily will be reviewed Thursday by the Technical Advisory Committee of the Berkeley-Charleston-Dorchester Council of Governments. The utility is asking the Council for an amendment to its 2008 Water Quality Management Plan.