SALISBURY — A chemical compound called zinc orthophosphate will be at the forefront of Rowan County’s efforts to eliminate lead in drinking water in the Dukeville area.
The county has been working for months to fix the elevated levels of lead found in some homes serviced by the northeast water system, which serves 162 connections and several hundred residents. It is owned by the county, but the water is treated by Salisbury-Rowan Utilities.
Water sampling efforts have found elevated levels of lead in the drinking water of nine customers on the system. Overall, 116 active metered connections have been tested.
The plan to eliminate the threat of lead was presented to the Rowan County Board of Commissioners during its meeting Monday afternoon by representatives from Hazen and Sawyer, an engineering firm hired by the county.
Roger Arnold, an engineer with Hazen and Sawyer, told commissioners during the meeting zinc orthophosphate in conjunction with raising the pH level of water is the answer to stopping lead from seeping into drinking water from the pipes in some customers’ homes. Zinc orthophosphate was shown to be the right chemical compound for the job by a series of tests conducted by Virginia Tech, who was contracted by Hazen and Sawyer.
The plan is for Salisbury-Rowan Utilities to switch from using a polyphosphate blend at their water treatment facility to using zinc orthophosphate. More zinc orthophosphate will then be added at a chemical booster station at the entry point to the northeast water system.
Five companies placed bids to build the chemical booster station. The low bid came in at $742,900 and was from Dellinger, Inc. Commissioners approved the bid during the meeting Monday as well as an easement for land to build the station. The city of Salisbury must also approve the easement, since the station will be built on its property.
Once the easement is approved by Salisbury and commissioners approve the contract with Dellinger at their meeting on April 19, construction on the station will begin.
Located at 1375 Long Ferry Road, the station will feature metering pumps, 55-gallon drums, a control station and other equipment needed to inject and monitor pH levels and the amount of zinc orthophosphate in the system. Once it is in the system, zinc orthophosphate will act as a corrosion inhibitor, preventing any lead from seeping into drinking water from pipes in customers’ homes.
The corrosion control treatments are still subject to review by the North Carolina Department of Environmental Quality.
NCDEQ has given the county until June 12 to gain compliance, or else it may face penalties for being in violation. The county hopes that its proposal of switching to zinc orthophosphate and altering the pH level will help it be in compliance.
Even after the necessary steps are taken, County Manager Aaron Church said it will take time for the water to be completely safe.