Presentation - WQC Final Report for 1-4 dioxane

Final Report on 1,4-dioxane in the Cape Fear River Basin &
Path Forward
EMC Water Quality Committee
November 13, 2024
•No later than three years from the date of the Commission’s adoption
of the revised SOC for Greensboro, DEQ is to issue a report to the WQC
that makes recommendations for additional steps to be taken by DEQ
and/or the Commission to achieve compliance with the water quality
standard for 1,4-dioxane if any classified surface waters within the
Basin have not yet achieved compliance.
•Greensboro has made significant reductions in its 1,4 dioxane
discharge. A 1,4-dioxane limit was put in the Asheboro permit –this
permit was contested. Four other facilities have elevated levels of 1,4-
dioxane.
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From Greensboro Special Order of ConsentSOC
Settlement Agreement:
City of Greensboro’s
Special Order by Consent (SOC) for 1,4-dioxane
•Original two-year SOC approved by EMC in March 2021, with an effective date of
May 1, 2021:
•Two Year SOC with Compliance Values: Year One: 45 µg/l, Year Two: 33 µg/l
•Fayetteville Public Works Commission and Haw River Assembly filed legal petition
against SOC in April 2021.
•Due to settlement negotiations, an amended three-year SOC was approved by
EMC in November 2021, with an effective date of December 1, 2021:
•Three Year SOC with lower Compliance Values: Year One: 35 µg/l, Year Two: 31.5
µg/l, Year Three: 23 µg/l
•Settlement stipulated that EMC direct DEQ to supplement its 1,4-dioxane study to
include semi-annual progress reports to the WQC on DEQ’s 1,4-dioxane actions in
the Cape Fear River Basin.
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Greensboro: Current Status
•SOC expired July 15, 2024.
•Greensboro submitted Year Three Report on May 31, 2024.
•During SOC Year Three, the City collected over 602 1,4-dioxane samples and
spent $77,526 in commercial lab testing.
•All data and reports are on Greensboro’s website:
•1,4-Dioxane Updates | Greensboro, NC (greensboro-nc.gov)
•Greensboro has not exceeded SOC Compliance Value since Year
One.
•Conclusion: SOC was effective and helped the City to identify
Significant Industrial User (SIU) sources and take pretreatment
actions to reduce 1,4-dioxane concentrations.
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Greensboro Post SOC Voluntary Actions: Ongoing
•SOC Year Three ended on April 30, 2024.
•City is now conducting post-SOC voluntary actions that are similar to SOC Year
Three requirements.
•City is continuing weekly effluent grab sample monitoring and will report
within 24 hours to DEQ and notify downstream utilities if result >23 µg/L
(equal to SOC Year 3 Compliance Value)
•City will maintain current pretreatment program mechanisms, modify permits
as necessary, and require select SIUs to collect and retain daily samples
•City will also continue the following sampling and monitoring activities:
•Pittsboro drinking water intake (weekly)
•Haw River Arm of Jordan Lake (twice per month)
•Influent composite sample (weekly)
•Surveillance monitoring in wastewater collection system
•Retain weekly composite of daily effluent samples
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City of Asheboro, permit issued August 2023
• Permit was appealed: ALJ final ruling on September 12, 2024, ordered that
the 1,4-dioxane limitations set in NPDES permit NC0026123 for the Asheboro
WWTP are void and unenforceable, and that all other conditions of the permit
are effective.
• On October 7, 2024, per the existing Delegation MOA requirements with EPA,
DWR sent a letter to EPA Region 4 for comment on the Asheboro Permit
changes, as well as a copy with the court-ordered changes, denoted as
strikethroughs.
• On October 13, 2024, DEQ filed a petition for judicial review and motion for
stay in Wake County Superior Court.
City of Asheboro WWTP – NPDES Permit
2024 Triennial Review – 1,4-dioxane
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•Adopting a numeric standard to 1,4-dioxane was included as a part
of the Draft 2024 Triennial Review
•It was determined to wait and use the Collaboratory Report on
treatment technology and cost of those treatments for 1,4-dioxane
(H 600, Section 9b.)
•Staff continues to work on updating the 1,4-dioxane Rule Package.

Path Forward for WQC
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1,4-dioxane Numeric Standard
•North Carolina is obligated under the
CWA to establish regulatory standards
for toxic substances to protect down
stream uses.
•Return to WQC with draft rule
consistent with best available science
and CWA.
Focus on Source Control
•Require pretreatment programs to
address SIU contributions and require
BMPs or minimization plans.
•Continue sampling at facilities with
elevated levels of 1,4-dioxane.
•Identify what levels of 1,4-dioxane
trigger a minimization plan.
•Define reduction targets ensures success
that protection of downstream uses.
DEQ Seeks Guidance on Recommendations for 1,4-dioxane
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Discussion / Questions