Wednesday, June 29, 2022

DEQ’s comments on Brunswick’s reverse osmosis discharge permit so far

Brunswick County's proposed concentrate discharge permit, required for the operation of its planned reverse osmosis facility, has received several comments from the state so far.

Brunswick County's Northwest Water Treatment Plant will soon get an update in excess of $100 million, including a plant expansion and new reverse osmosis technology. (Port City Daily photo/Courtesy Google Maps)
Brunswick County’s Northwest Water Treatment Plant will soon get an update in excess of $100 million, including a plant expansion and new reverse osmosis technology. (Port City Daily photo/Courtesy Google Maps)

BRUNSWICK COUNTY — Brunswick County has plans to operate one of the largest — if not the largest — reverse osmosis plants in the state.

Inherent in the reverse osmosis process is discharging concentrated material, which requires a National Pollutant Discharge Elimination System (NPDES) permit.

Related: Brunswick County leaders talk water infrastructure projects, and where to find $216 million dollars

The state, so far, has provided the county two sets of feedback on its application.

Brunswick’s plans

It will cost Brunswick County between from $89.5 million to $99.6 million, depending on the estimate, to upgrade its traditional water filtration system at its Northwest Water Treatment Plant. Funding for this system, among other utility improvements, is actively being sought.

Fitted to service a previously planned 12 million-gallon-a-day (mgd) expansion, a separate $47.5 million project, the planned reverse osmosis system will treat 36 mgd. To do this, discharge concentrate would flow through a nearly 4-mile pipeline into the Cape Fear River.

Brunswick County is seeking a permit that would allow up to four mgd of discharge. However, according to the county’s NPDES permit application, the discharge will rarely meet its fullest capacity.

The permit application, submitted in November 2018, states discharge will not exceed state standards. Pilot testing shows four parameters out of 280 tested revealed levels in excess of state standards or protective values. These parameters, manganese, aluminum, chloride and dichloracetic acid, will be diluted in the county’s final stream, the applications states.

Though there are more than one dozen reverse osmosis facilities in the state, none appear to match the size and capacity of Brunswick County’s proposed plant. When asked for the closest comparison, a CDM Smith representative cited a Dare County plant on Jan. 15. That plant’s capacity is 5 mgd, a seventh of what Brunswick County is planning.

At a Jan. 17 Leland Council meeting, Brunswick County officials briefed councilmembers on the plant’s status. Reed Barton, a CDM Smith engineer, was asked by Councilman Michael Callahan whether the discharge would have a negative impact on fishing and marine life.

“The answer is no,” Barton said. “There are no studies indicating it would cause a negative effect on the environment.”

On a typical day, Barton said the concentrate will make up less than 0.1 percent of the total water in the river. “We’re talking about drops in the bucket,” he said.

Story continues below map. Check out the proposed concentrate discharge’s 4-mile path, from Brunswick County’s water treatment plant to the Cape Fear River: 

DEQ’s first comments

The North Carolina Department of Environmental Quality (DEQ) has the authority to grant NPDES permits, like the one Brunswick County is seeking.

Two sets of DEQ’s comments have been offered since the permit’s submission in November: a preliminary response on Dec. 14, 2018, and a formal request for additional information on Jan. 11. In meetings during the week of Jan. 14, CDM Smith representatives did not specifically address DEQ’s Jan. 11 comments. While referencing DEQ’s December comments on Jan. 17, Barton said none of the state’s technical comments were significant or negative.

“All the interactions we’ve have with the state have been very positive,” he said. On Tuesday, Nichols confirmed CDM Smith’s initial characterization of DEQ’s responses also applies to the state’s Jan. 11 comments, noting the comments are of a typical nature.

On Dec. 14, among other technical comments, DEQ informed the county it did not conduct testing in consideration of the proposed outfall location’s state water classification. Modeling was analyzed in accordance with requirements of “Class C” waters, also known as “swamp waters.” Though the outfall location is indeed designated as Class C water, it’s also a Primary Nursing Area, the DEQ’s response states.

In its first comments, DEQ asked the county to revise its analysis. The revision will take into account the additional requirements triggered by a Primary Nursing Area (PNA) designation, outlined in 15A NCAC 02B .0224.

PNAs are vitally important fish habitats, Curtis Weychert, a DEQ Fisheries Resource Specialist said. According to Weychert, the Environmental Management Commission prohibits new point source discharges in PNA waters (without a permit, that is).

The Division of Marine Fisheries (DMF) has the authority to comment on or object to permits submitted to state agencies regarding activities that may impact public trust resources, Weychert said. As of Jan. 22, Weychert said DMF has not yet received any information about Brunswick County’s project.

In 2018, in The Division of Coastal Management reviewed 67 projects in the state’s southern district. The state objected to seven and provided comments to nearly half.

When asked about the water classification of the outfall location, John Nichols, the county’s utility director, said it will likely require additional analysis and testing. “It’s not unusual to have those types of comments,” Nichols said on Jan. 15. “As far as I know, my understanding is that it does require some additional information to be supplied.”

Second comments

On Jan. 11, DEQ followed up with a formal letter. In this letter, DEQ offered 12 comments, asking Brunswick County to provide more information, including some of the following items:

  • To include analysis of several parameters in concentrate waters including: arsenic, beta particles, nitrogen-nitrate + nitrite, total phosphorus, total nitrogen, total suspended solids, lead, pH, radium 226 and 228. According to DEQ’s comments, this information was not included in the permit.
  • To clarify whether detergents will be disposed of at the plant or offsite. The county’s permit states the neutralized solution resulting from the use of detergent will be disposed of at the plant and hauled separately.
  • To confirm where sludge will be disposed of.
  • To perform proper population and flow projections, which DEQ states may not have been initially followed.
  • To submit additional information and documentation to support CDM Smith’s conclusion that alternative disposal options are not feasible.

The back-and-forth between the county and the state regarding a new permit is just business as usual, Barton said on Jan. 17.

“This is all very normal business for water and wastewater type work,” he said.

Compared to New Hanover County, currently pursuing a $46 million granular activated carbon (GAC) system, Brunswick County has more ground to cover. According to Nichols, Brunswick County does not currently offer advanced treatment, like CFPUA does, at the Northwest Water Treatment Plant. “We have a clean slate,” he said.

Related: CFPUA filtered water still has more contaminants than raw water. Here’s why, and what’s being done

And as recently reported by Port City Daily, GAC has its own complications. When filters are not exchanged in a timely manner, they can actually “desorb” contaminants that were previously captured back into the water. This has, at times, resulted in treated water more contaminated than raw water.

So far, Brunswick County’s model shows that contaminants get dispersed quickly at the outfall location, according to Barton. “The model shows that in a very, very short amount of time — just a few feet — you can take samples across the entire river and you wouldn’t be able to tell the difference,” he said.

At month two of an estimated six-month permitting process, the county anticipates having a permit in hand in May.


Send tips and comments to Johanna Ferebee at johanna@localvoicemedia.com

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