Brunswick County received updates about water treatment methods from CDM Smith at Monday night’s meeting, after CDM Smith answered questions during a tour for wholesale customers, media and community partners at the Northwest Water Treatment Plant Monday afternoon.
CDM Smith, an internationally-known firm based out of Raleigh, is consulting with emerging contaminant experts Dr. Charles E. Schaefer, Jr., Dr. Philip C. Singer and Dr. Detlef Knappe, utilizing data from prior studies, and conducting pilot-scale testing of low pressure reverse osmosis and bench-scale testing of UV-AOP treatment.
Monday night’s presentation included preliminary information about water treatment options and their associated budgetary cost information, initial reverse osmosis pilot testing data, and potential treatment targets for unregulated contaminants of concern. CDM Smith’s presentation also includes capital cost estimates for expansion components to bring the treated water capacity from 24 million gallons per day (MGD) to 36 MGD, as well as operation and maintenance costs.
Officials with CDM Smith evaluated ion exchange, reverse osmosis, granular activated carbon, UV-advanced oxidation process and ozone-biofiltration treatment methods, independently and in tandem, for their ability to treat Per- and Poly-flouroalkyl Substances (PFAS) like GenX, as well as other compounds like 1,4-Dioxane, pharmaceuticals and personal care products (PPCPs) and endocrine disruptive compounds (EDCs). The firm recommended low pressure reverse osmosis to the Board of Commissioners, noting that it has the lowest net present worth costs for removing 90 percent or more of the target contaminants.
Since Brunswick County would use reverse osmosis to remove compounds like GenX from water that had already been treated by Brunswick County’s current treatment methods, the County would be able to use a low pressure reverse osmosis system, CDM Smith officials said. A low pressure system would cost less to operate and use less water than the type of reverse osmosis system that would be used to remove solids or salinity from ground water, officials told the Commissioners, as removing that type of substance would require more pressure to push the water through the membranes used in reverse osmosis filtration.
The total capital construction costs for a low pressure reverse osmosis treatment system presented Monday night were $99 million. County officials estimated that the cost would result in a rate increase of $6.21 per month for the typical home, billed monthly for 4,500 gallons – a number which will also be pursued as damages in the County’s legal proceedings against the companies that have discharged emerging or harmful chemicals into the water supply.
Among the data presented Monday night, CDM Smith told the Board of Commissioners that preliminary lab results from samples taken Feb. 26 showed non-detectable levels of GenX, Nafion Byproduct 1 and 2, and all other PFASs in water treated with the Low Pressure Reverse Osmosis pilot unit.
A final report and results from the Reverse Osmosis pilot unit will be presented Apr. 16, and after an option is selected, preliminary design work is expected to start in May, with final design work expected to start in July. Design work should take approximately a year, with construction beginning in the 2019-20 fiscal year and taking approximately 18 months to complete.
Brunswick County’s litigation efforts against DuPont and Chemours continue, as the county seeks to hold those responsible for the discharge of emerging or harmful chemicals into the public drinking water supply accountable and to ensure that the costs for long-term water testing and treatment methods for those chemicals do not fall upon rate payers, but upon those dumping the harmful chemicals in the water.
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. Brunswick County is evaluating treatment options that address water quality issues affecting all of the more than 70,000 customers within the County, rather than just a small subset of customers. This approach allows Brunswick County to take advantage of economies of scale associated with the construction costs of additional water treatment methods.
Updates about these water treatment improvement plans, Brunswick County’s water testing results and GenX in general are posted online at https://www.brunswickcountync.gov/genx/ and emailed to those who have signed up for notifications at http://eepurl.com/ZT6tb.