Brunswick County's Board of Commissioners voted unanimously to approve the construction of a $99 million low-pressure reverse osmosis plant.
The approval came at the board's budget workshop Thursday, a measure that is expected to provide "a forward-thinking, long-term water quality solution for all customers that receive water from Brunswick County," county officials said in a news release.
Preliminary design work has begun, with final design work expected to begin in September, officials said in the release. The application process for the N.C. Department of Environmental Quality to modify the county’s existing discharge permit began in February and has proceeded with no “red flags” from regulators, the release stated.
Bidding and construction of the project is expected to begin in June 2019.
Along with the $99 implementation of water solution, additional operations and maintenance costs are approximately $2.9 million per year.
The Brunswick County Board of Commissioners received a report on April 16, from CDM Smith, a firm hired to research and review data, conduct pilot tests and consult with experts regarding advanced water treatment methods and the presence of chemicals in the Cape Fear River, where Brunswick County draws water for treatment.
CDM Smith recommended low-pressure reverse osmosis (LPRO) as the "most efficient and cost-effective advanced water treatment addition to the Northwest Water Treatment Plant," county officials said in the release.
After hearing the recommendation in April, commissioners and county staff reviewed CDM Smith’s report and findings, along with information about the effectiveness and cost of other treatment methods.
The board voted Thursday to move forward with implementation of LPRO "as the most cost-effective long-term solution for Brunswick County water treatment," county officials said in the release.
Representatives from CDM Smith told commissioners all but one of the perfluorinated chemicals were not detected in the treated water using the best technology currently available,
"Testing was completed to determine the presence and amount of more than 45 compounds, including GenX, Nafion Byproduct 1 and Nafion Byproduct 2, Perflourooctanesulfonic acid (PFOS), Perfluorooctanoic acid (PFOA), 1,4-Dioxane and PFMOAA in the water before and after treatment by the LPRO unit. The testing results also showed a 94 percent removal of 1,4-Dioxane, taking it from 3.2 µg/L before the LPRO treatment to 0.2 µg/L after treatment. Other substances, including the insect repellant DEET, the herbicide Atrazine, and the seizure medicine Carbamazepine were not detected in the LPRO-treated water," county officials said in the release.
In recommending LPRO, CDM Smith officials said that its operational and maintenance costs are less than other methods that would require frequent changing of filtration material, and that using LPRO after the county’s current filtration methods would cost less than a higher-pressure system that would be needed to treat brackish groundwater, according to the release.
“The net present worth, the life cycle cost if you will, of reverse osmosis is almost half of the other [treatment methods and method combinations considered],” Bill Dowbiggin, senior vice president and senior environmental engineer with CDM Smith, told the commissioners in April.
Brunswick County had plans to expand the capacity of the Northwest Water Treatment Plant to meet the demand of its customers, prior to the discovery of GenX in the Cape Fear River. Those plans remain in place, officials said, and the proposal for LPRO includes plans to accommodate that increase in capacity.
In addition to serving over 40,000 retail customers, Brunswick County has ten wholesale utility water customers that serve over 30,000 additional retail customers within Brunswick County, according to the release.
Brunswick County officials said they are evaluating treatment options that address water quality issues affecting all of the more than 70,000 customers within the county.
"This approach allows Brunswick County to take advantage of economies of scale associated with the construction costs of additional water treatment methods," county officials said in the release. "Brunswick County has also evaluated treatment options that are effective on a number of chemicals found in the Cape Fear River, including some only recently discovered. In considering these options, as well as the potential for new chemical discoveries or regulatory changes in years to come, Brunswick County is ensuring that the treatment method selected will provide a long-term solution for the needs of all customers who receive water from Brunswick County or one of its wholesale customers, now and in years to come."
