BRUNSWICK COUNTY — The Northeast Wastewater Treatment Facility operated at 110 percent of its state-permitted capacity in December.
In January, the Department of Environmental Quality (DEQ) notified the plant it violated its permit and notified the plant of its intent to issue a civil penalty for exceeding the monthly permitted average flow of wastewater.
According to the DEQ, the sewage treatment plant is currently at 92 percent of its current flow capacity. That leaves the plant with roughly less than a 200,000 gallon-per-day buffer before breaching its permitted limit again.
The plant is only permitted to treat 2.475 million gallons a day (mgd) of wastewater. It exceeded that during the month of December 2018, according to the DEQ Division of Water Resources (DWR) violation notice, treating a monthly average effluent flow of 2.7233 mgd.
A DEQ spokesperson said the department hasn’t assessed the plant’s civil penalty yet.
Generally, wastewater plants operating at full capacity can create system vulnerabilities, according to multiple experts in the field. These vulnerabilities can lead to sewer system overflows, pipe bursts and leaks due to high pressure, and contaminated discharges into surface water. This isn’t the first time the DEQ fined the plant for issues connected to its high operating capacity. (Stay tuned for a more in-depth look at what happens when a sewage treatment plant functions at full or over capacity in part two of this story).
Pushing capacity limits
Northeast Wastewater Treatment Plant is the sole sewer treatment that accepts flow from the Town of Leland’s collection system. It accepts approximately 65 percent of Brunswick Regional Water and Sewer H2GO’s wastewater, H2GO’s spokesperson estimated. The plant handles all wastewater for Navassa and Northwest, municipalities without their own treatment facilities.
The plant is located off Royster Road in Navassa, with a National Pollutant Discharge Elimination System permit. That permit, regulated under the Clean Water Act, allows the plant to discharge treated wastewater into the Cape Fear River.
In October 2016, Northeast Wastewater Treatment Plant (NEWWTP) operated at nearly 90 percent of its permitted capacity, according to a 2017 capacity study, conducted by Brunswick County’s consultant McKim & Creed.
Data made available in the study showed in October 2016 unincorporated Brunswick County used less than a third of its allocated flow; Northwest used less than one fifth, and Leland used about two-thirds. H2GO billed 1.2 times above its allocated limit, and Navassa sent two-and-a-half times over its limit.
At a Leland Council meeting on Jan. 17, John Nichols, the county’s utilities director, provided an update on NEWWTP’s flow rate. “Right now we have two entities that are over their allocation on a pretty consistent basis,” he told Leland’s town Council. “That’s the Town of Navassa and H2GO.”
Brunswick County is in the process of planning an expansion at the facility that would double its capacity. Construction on the expansion won’t begin until January 2020, according to the county. Historically, utility usage peaks during summer months. However, according to Nichols, this same rule doesn’t apply to NEWWTP, because it does not receive wastewater flow from beach communities.
NEWWTP’s peak flows occur in the fall and winter, Nichols said Wednesday. It peaks during this time period due to excessive rains and higher groundwater, he said. Compounding the issue, Nichols said, storm events during this period can lead to increased inflow and infiltration — a negative indicator of a plant’s ability to treat sewage.
What happened? Brunswick County responds
In a response to DEQ’s violation notice, Nichols wrote the flow exceedance was due to months of heavy rainfall, rather than a single storm event. Over 55 inches of rainfall between July and December 2018 impacted the plant’s ability to reduce inflow and infiltration, Nichols told the DEQ. Since Hurricane Florence in September, Nichols said groundwater tables in the regional collection system continue to be “extremely high.”
So far this fiscal year, Nichols said in a statement that NEWWTP’s peak flow occurred in December 2018. The previous fiscal year, peak flow was recorded in January 2018; the fiscal year prior, peak flow occurred in October 2016; and in fiscal year 2017, peak flow was recorded in February 2016.
Based on historical data, Nichols expects a downward trend will continue in the summer months. In his letter to the DEQ, Nichols said flow was down by 400,000 gallons per day and would average below its permitted 4.475 limit.
“Although record rainfalls caused the Northeast Regional WWTP to be over its hydraulic capacity, the wastewater plant was still able to maintain compliance with its permitted discharge limits for the components within the wastewater stream,” Nichols wrote in a statement to Port City Daily. “Moreover, Brunswick County has reached out to the participants within the system – H2GO, Leland, the Town of Navassa, and the City of Northwest – to take steps to reduce Inflow & Infiltration into their collection systems that send flow to the Northeast Regional Wastewater Treatment Plant and will continue to work with them to manage wastewater flows to reduce the potential for future exceedance of the hydraulic capacity.”
H2GO is the largest contributor of wastewater to NEWWTP, generating slightly more than the town of Leland. It’s worth noting that H2GO, which has consistently gone over its allotted outflow into NEWWTP, can’t increase its in-house treatment capacity even though it has its own wastewater plant in Belville.
According to a 2001 sewer-service agreement, H2GO cannot expand that plant until 2040, effectively capping its capacity until then. According to an H2GO spokesperson, this arrangement stemmed from a lawsuit with Brunswick County.
(Stay tuned for part two, which will explain the potential impacts of a facility operating at or near its permitted capacity)
Update 11:21 a.m.: This article first stated the plant has a roughly less than a 500,000 gallon-per-day buffer. It’s been corrected to state the county actually has a 200,000 gallon-per-day buffer.
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