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Home My WebLink AboutNC0021849_NC0021849 Draft Factsheet 2023_20231114NCDEQ / DWR / NPDES EXPEDITED FACT SHEET - NPDES PERMIT RENEWAL NPDES Permit NCO021849 Caroline Robinson / Compliance & Expedited Permitting Unit / caroline.robinson@deq.nc.gov / Oct 2023 FACILITY INFORMATION Applicant/Facility Name Town of Hertford (Janice Cole, Town Manager) Hertford WWTP Applicant Address / Facility Physical Address 114 West Grubb Street, Hertford, NC 27944 Mailing Address P. O. Box 32, Hertford, NC 27944 Permitted Flow (MGD) 0.7 MGD Type of Waste Municipal, < 1MGD Facility Class WW-3 County Perquimans Permit Status Renewal Regional Office WaRO STREAM CHARACTERISTICS Receiving Stream Perquimans River Stream Classification SC Stream Segment 30-6-(3) Outfall Lat. 360 11' 51" N 7Q 10 - Summer (cfs) Tidal Stream Outfall Long. 760 28' 08" W 7Q 10 - Winter (cfs) Tidal Stream Drainage basin Pasquotank River Basin 30Q2 (cfs) Tidal Stream Subbasin 03-01-52 Average Flow (cfs) HUC 030102050303 IWC (%) 303(d) List No BASIC INFO FOR EXPEDITED PERMIT RENEWAL NH3 limits were added when the POTW expanded to 0.7 MGD based upon the speculative limit issued in Does permit need Daily Max NH3 limits? 1998. Due to the tidal stream, the limits cannot be recalculated using the toxicity spreadsheet. Facility has been compliant with NH3 limits during the last permit cycle. Limits will remain unchanged. Does permit need TRC limits/footnote? TRC limit is at the standard for salt waters Does permit have toxicity testing? No — not a complex wastestream Does permit have any Special Conditions? Yes — effluent mercury analysis Does permit have instream monitoring? Yes — U & D for Temperature and Dissolved Oxygen New expiration date: December 31, 2027 FACILITY SUMMARY Town of Hertford operates a municipal wastewater treatment plant for an estimated 2,735 residents for the Town of Hertford (Population 2,135) and the Town of Winfall (Population 600). The Hertford Wastewater Treatment Plant is a minor facility (flow < 1 MGD) with a design capacity and permitted wastewater discharge of 0.7. This facility is 100% domestic with no pretreatment program. The original NPDES permit for this facility was issued in November 1981. The WWTP was expanded and upgraded from 0.4 MGD to 0.7 MGD in March 2010. The town requested a permit modification on January 12, 2011 to increase discharge to 0.975 MGD from the permitted 0.7 MGD. An Engineering Alternatives Analysis (EAA) was submitted with the request. A review of the EAA by the Complex NPDES Permitting Unit staff determined that the EAA was very incomplete, did not justify the proposed flow increase and did Fact Sheet for Permit Renewal Oct 2023 - NPDES Permit NCO021849 - Page 1 not thoroughly evaluate alternatives, such as non -discharge via spray irrigation. The flow increase sought was primarily based on excessive I & I that Hertford had been working on eliminating for years. Hertford was informed that the Division cannot grant an expansion based only on excess I & I, that EPA would challenge the permit if we did. The two towns worked together and reduced the I & I to an acceptable level and requested renewal of the existing permit in September of 2012. This facility utilizes the following treatment components: • Dual Mechanical bar screens • Dual Parshall flumes (with two flow meters) • Grit removal system • Influent pump station with three pumps • Oxidation ditch • Flow splitter • Two (2) Secondary Clarifiers • WAS pump station with dual pumps • Dual automatic backwashing disk filters • Chlorination using gaseous chlorine • Dual 27,500 gallon chlorine contact chambers • Dechlorination using sulfur dioxide gas • Outfall diffuser • One 55,000 gallon aerobic sludge digester • One 328,000 gallon sludge holding basin, with fine bubble diffusers • Sludge drying beds • Sludge loading station for trucks • Three (3) 125 kW back up generators with automatic transfer switches • Flow meter downstream of the chlorine contact chamber and sulfur dioxide injection RENEWAL SUMMARY This renewal contains the following changes: • Electronic data submission requirements have been updated. PERMITTEE REQUESTED MONITORING FREQUENCY REDUCTION The Town of Hertford requested monitoring frequency reductions for BOD, TSS, and Ammonia Nitrogen. Per the October 2012 guidance document, a review of their DMR data and their compliance history from the last three years was done (August 2020 — August 2023). Based on this review, discussions with the Washington Regional Office, and the most recent inspections at this plant, this facility is ineligible for a reduction of monitoring for BOD, TSS, and Ammonia Nitrogen. • No enforcements for each requested parameter in the past 3-years? o Yes — eligible • No more than two non -monthly average limit violations for each parameter in the past year o Yes — eligible • Not under an SOC for the requested parameters? o Yes — eligible • Not on EPA's QNCR for the requested parameters? o Yes, however, the facility is listed on the EPA's QNCR for other violations — eligible • Data review — BOD, TSS, and Ammonia Nitrogen o Yes — eligible • Discussion with Washington Regional Office regarding approval for the MFR: o Robbie Bullock (Environmental Program Consultant) noted that the last inspection dated 11/16/2022 was non -compliant and that several of the facility components were nonoperational, including, the mechanical bar screen, the grit removal system, the two aerators in the oxidation ditch, and tertiary filters. He also noted that the 2/24/2021 Fact Sheet for Permit Renewal Oct 2023 - NPDES Permit NCO021849 - Page 2 inspection was also non -compliant. Therefore WaRO is not in favor of reduced monitoring. - Ineligible See data evaluation attached. COMPLIANCE HISTORY Hertford WWTP has had four enforcements on record for an untreated wastewater bypass in 2019, a spill at the mechanical bar screen in 2020, an unauthorized bypass of unknown quantity and one nonoperational automatic disk filter in 2021, and nonoperational equipment in 2022, including aerators on the inside ditch, the mechanical barscreens, the grit removal system, and the SCADA system for the influent pump station. The facility has been issued one NOV in 2021 for a flow limit violation, one NOV in 2021 and one NOV in 2022 for permit condition violations, and one NOV for a Total Suspended Solids limit violation in 2023, since the permit was originally issued in July 2018. Most recent inspection (November 2022) showed the facility to be in noncompliance. Several components of the wastewater treatment plant were either not operating or were only partially operational, including the mechanical barscreens, the grit removal system, two oxidation ditch aerators, tertiary filters, an effluent pump station EFFLUENT MERCURY ANALYSIS The permittee is required to provide one effluent mercury analysis, using EPA Method 1631E, in conjunction with the next permit renewal application. The analysis should be taken within 12 months prior to the application date. Any additional effluent mercury measurement conducted from the effective day of this permit and up to the application date shall also be submitted with the renewal application. This facility has reported an effluent mercury analysis for this permit cycle using EPA Method 1631E, dated March 25, 2022. Outfall Mont Da Year Parameter Para Sample UoM Value h y m Class 002 3 25 202 COMER - Metal Grab ng/I 3 2 Mercury, Total (as Hg) - Concentration COMMENTS ON DRAFT PERMIT Jeffrey Talbott (Operator Certification Group) noted that the facility is classified as a WW-3 facility with the ORC and all Backup ORC's active and in good standing with the program. Robbie Bullock (Environmental Program Consultant — Washington Regional Office) noted that the draft permit had the pH limit as greater than 6 and less than 9, and the pH limit in the existing permit was greater than 6.8 and less than 8.5. Mr. Bullock asked if the draft permit limit for pH was correct, and the draft permit was edited to reflect the previous permit. The pH was changed back to greater than 6.8 and less than 8.5 since pH is tied to stream classification and this facility discharges to a saltwater stream. Mr. Bullock also noted that WaRO is NOT in favor of reduced monitoring, since the last inspection dated 11/16/2022, was non -compliant and the facility had multiple issues. The mechanical bar screen, grit removal system, two aerators in the oxidation ditch, and tertiary filters were all non -operational. Mr. Bullock also noted that the prior inspection, dated 2/24/2021 also showed that the facility was non -compliant. Fact Sheet for Permit Renewal Oct 2023 - NPDES Permit NCO021849 - Page 3