DEQ Issues Water Treatment & Discharge Permit to Colonial Pipeline

The N.C. Department of Environmental Quality’s (DEQ) Division of Water Resources (DWR) has issued National Pollution Discharge Elimination System (NPDES) permit #NC0090000 to Colonial Pipeline Company (Colonial Pipeline) for remediation of a major petroleum spill near Huntersville, Mecklenburg County. 

The NPDES permit requires Colonial Pipeline to treat recovered groundwater to remove contaminants before discharging the treated groundwater to North Prong Clark Creek in the Yadkin-Pee Dee River basin. The treatment system is 
part of Colonial Pipeline’s fuel recovery and groundwater remediation to address its August 2020 fuel release in the Oehler Nature Preserve near Huntersville, as outlined in the 2022 Consent Order. The Consent Order holds Colonial Pipeline accountable as the responsible party for the state’s largest gasoline spill and included a $4.75 million-dollar civil penalty. Cleanup efforts and remediation are ongoing, with oversight by DEQ’s Division of Waste Management.

DWR issued the permit following a public engagement period during which DWR solicited public comments for a permit draft. Additionally, an in-person public hearing was held in Huntersville on March 16, 2023, where public comments were accepted and reviewed. Based upon a thorough review of the public record and in response to the public comments submitted, the following revisions were made to the draft permit:
1.    More stringent limits on five (5) parameters (including Benzene and Ethyl Benzene) were added to the final permit and the monitoring frequency for all volatile organic compounds (VOCs) was increased to monthly monitoring.
2.    Increased monitoring requirements and instream assessment of biological integrity were added to address concerns for aquatic life, the presence of threatened or endangered species, and stream impairment.
3.    PFAS monitoring of the effluent was added to the permit based on a review of recent groundwater data.
4.    Monitoring and reporting of the treatment system will be required for six (6) internal sampling points within the treatment system for performance evaluation.
5.    A permit reopener condition was added for any additional monitoring (e.g., effluent, instream, etc.) DWR deems necessary to support water quality protection, groundwater protection, and restoration efforts in the receiving stream. 
6.    Additional permit conditions to address potential nuisance conditions from the groundwater remediation operations. 
Copies of the final permit and related information are available online.