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HomeMy WebLinkAboutNC0021474_Fact Sheet_20230817 (2)Page 1 of 20 Fact Sheet NPDES Permit No. NC0021474 Permit Writer/Email Contact Nick Coco, nick.coco@deq.nc.gov Date: July 26, 2023 Division/Branch: NC Division of Water Resources/NPDES Municipal Permitting Fact Sheet Template: Version 09Jan2017 Permitting Action: ☐Renewal ☒Renewal with Expansion ☐New Discharge ☐Modification (Fact Sheet should be tailored to mod request) Note: A complete application should include the following: •For New Dischargers, EPA Form 2A or 2D requirements, Engineering Alternatives Analysis, Fee •For Existing Dischargers (POTW), EPA Form 2A, 3 effluent pollutant scans, 4 2nd species WET tests. •For Existing Dischargers (Non-POTW), EPA Form 2C with correct analytical requirements based on industry category. Complete applicable sections below. If not applicable, enter NA. 1.Basic Facility Information Facility Information Applicant/Facility Name: City of Mebane/Mebane Wastewater Treatment Plant (WWTP) Applicant Address: 106 E. Washington Street, Mebane, NC 27302 Facility Address: 635 Corregidor Road, Mebane, NC 27302 Permitted Flow: 2.5 MGD, with expansion flow tiers at 4.0 MGD and 6.0 MGD Facility Type/Waste: MAJOR Municipal; 93.5% domestic, 6.5% industrial* Facility Class: Grade IV Biological Water Pollution Control System Treatment Units: Influent bar screen, grit chamber, dual aeration basins, three final clarifiers, cloth media filtration, chlorine contact chamber, dechlorination, aerobic sludge digestors Pretreatment Program (Y/N) Y; LTMP County: Alamance Region Winston-Salem *Based on total permitted industrial flows. Briefly describe the proposed permitting action and facility background: The City of Mebane applied for renewal of NPDES permit NC0021474 for the Mebane WWTP at 2.5 MGD along with permit modification for the addition of expanded flow tiers at 4.0 MGD and 6.0 MGD on April 5, 2022. This facility serves a population of approximately 17,800 residents. The facility also accepts waste from 4 significant industrial users (SIUs) including 2 that are categorical (CIUs) via the City’s pretreatment program. Treated domestic and industrial wastewater is discharged via Outfall 001 into Moadams Creek, a class WS-V; NSW water in the Cape Fear River Basin. Sludge Disposal: Dewatered biosolids are transported by EMA Resources for use in production of compost by an additional third party. Page 2 of 20 2.Receiving Waterbody Information: Receiving Waterbody Information Outfalls/Receiving Stream(s): Outfall 001 – Moadams Creek Stream Index: 16-18-7 Stream Classification: WS-V; NSW Drainage Area (mi2): 0.9 Summer 7Q10 (cfs) 0 Winter 7Q10 (cfs): 0 30Q2 (cfs): - Average Flow (cfs): 0.8 IWC (% effluent): 90% @ 2.5 MGD, 4.0 MGD, and 6.0 MGD 2022 303(d) listed/parameter: Not listed Subject to TMDL/parameter: Yes- State wide Mercury TMDL implementation. Subbasin/HUC: 03-06-02/03030002 USGS Topo Quad: C21SE Note: Outfall 001 was relocated approximately 1,000 feet downstream on Moadams Creek in order to reduce the risk of flooding in the plant during heavy rain events as a 2017 permit modification. 3.Effluent Data Summary Effluent data for Outfall 001 is summarized below for the period of April 2018 through September 2022. Table 1. Effluent Data Summary Outfall 001 Parameter Units Average Max Min Permit Limit Flow MGD 1.6 6.494 0.671 MA 2.5 Total Monthly Flow MG 48.9 77.0 38.8 Monitor & Report BOD (summer) mg/l 3.7 17.9 < 2 WA 7.5 MA 5.0 BOD (winter) mg/l 3.5 20.7 < 2 WA 10.0 MA 15.0 TSS mg/l 3.0 17.5 2.5 WA 45.0 MA 30.0 NH3N (summer) mg/l 1.0 10 .05 WA 6.0 MA 2.0 NH3N (winter) mg/l 2.1 16.1 .05 WA 12.0 MA 4.0 DO mg/l 7.9 11 4.1 DA 6.0 Fecal coliform #/100 ml (geomean) 4.7 2420 < 1 (geometric) WA 400 MA 200 Temperature ° C 19.0 28 1.4 Monitor & Report pH SU 7.3 7.8 6.4 6.0 ≤ pH ≤ 9.0 Total Residual Chlorine µg/l 15.4 48 < 1 DM 17.0 Conductivity µmhos/cm 632 885 192 Monitor & Report TKN mg/l 2.9 16.3 0.57 Monitor & Report NO2+NO3 mg/l 1.8 11 0.1 Monitor & Report TN mg/l 4.8 17.83 0.95 Monitor & Report TN Load lbs/mo 2042 6457 916 Monitor & Report Page 3 of 20 TN Load lbs/yr 25,456 32,981 19,672 40,225 TP mg/l 0.8 9.8 0.07 Monitor & Report TP Load lbs/mo 330 957 19 Monitor & Report TP Load lbs/yr 3,910 4,799 3,008 5,056 Total Zinc µg/l 49.3 256 < 5 Monitor & Report MA-Monthly Average, WA-Weekly Average, DA-Daily Average 4. Instream Data Summary Instream monitoring may be required in certain situations, for example: 1) to verify model predictions when model results for instream DO are within 1 mg/l of instream standard at full permitted flow; 2) to verify model predictions for outfall diffuser; 3) to provide data for future TMDL; 4) based on other instream concerns. Instream monitoring may be conducted by the Permittee, and there are also Monitoring Coalitions established in several basins that conduct instream sampling for the Permittee (in which case instream monitoring is waived in the permit as long as coalition membership is maintained). Is this facility a member of a Monitoring Coalition with waived instream monitoring (Y/N): Y Name of Monitoring Coalition: Upper Cape Fear River Basin Association If applicable, summarize any instream data and what instream monitoring will be proposed for this permit action: The current permit requires instream monitoring for dissolved oxygen, temperature, fecal coliform and conductivity upstream 100 feet above the outfall and downstream at Moadams Creek at NCSR 1940 (D1), at Back Creek at NCSR 1940 (D2), and at Back Creek at NC Highway 54 (D3). Instream sampling is conducted three times per week during the months of June, July, August and September and once per week during the remainder of the year. Sampling at D2 is only required from June through September. The City is a member of the Upper Cape Fear River Basin Association (UCFRBA) and their instream requirements are provisionally waived as long as they maintain membership. The nearest upstream station is UCFRBA station B1350000 and the nearest downstream station is UCFRBA station B1380000. UCFRBA data are also available for ammonia, TKN, NO2+NO3, total phosphorous and turbidity. Instream data from January 2017 through December 2022 has been summarized below in Table 2. Table 2. Instream Monitoring Data Summary Parameter Units Upstream Downstream Average Max Min Average Max Min Temperature ° C 18.0 27.3 6.3 19.1 27.9 6.8 DO mg/l 8.1 11.5 5.4 8.5 12.1 6.1 Fecal Coliform #/100ml (geomean) 368 9800 31 (geomean) 98 5000 12 Conductivity µmhos/cm 161 224 47 420 748 119 Ammonia mg/l 0.04 0.17 < 0.02 0.27 3.62 < 0.02 TKN mg/l 0.50 1.96 < 0.2 1.12 3.84 0.22 NO2+NO3 mg/l 0.57 1.15 < 0.1 1.35 4.34 0.13 TP mg/l 0.03 0.239 < 0.02 0.37 3.09 0.065 Turbidity NTUs 18 139 5 11 57.1 1.9 Students t-tests were run at a 95% confidence interval to analyze relationships between instream samples. A statistically significant difference is determined when the t-test p-value result is < 0.05. Page 4 of 20 Downstream temperature was not greater than 29 degrees Celsius [per 15A NCAC 02B .0211 (18)] during the period reviewed. Downstream temperature was greater than upstream temperature by more than 2.8 degrees Celsius on 5 occasions during the period reviewed. It was concluded that no statistically significant difference exists between upstream and downstream temperature. Downstream DO did not drop below 5 mg/L [per 15A NCAC 02B .0211 (6)] during the period reviewed. It was concluded that no statistically significant difference exists between upstream and downstream DO. Downstream fecal coliform did not exceed a geomean of 200/100ml [per 15A NCAC 02B .0211 (7)(4)] during the period reviewed. Downstream fecal coliform exceeded 400/100ml in fewer than 20% of samples during the period reviewed. Upstream fecal coliform exceeded a geomean of 200/100ml and also exceeded 400/100ml in more than 20% of samples during the period reviewed. It was concluded that a statistically significant difference between upstream and downstream fecal coliform exists. However, this statistically significant difference is likely attributable to elevated fecal coliform levels upstream of the discharge. Conductivity is tracked as a parameter associated with industrial discharge. It was concluded that a statistically significant difference exists between upstream and downstream conductivity, with downstream conductivity being observed at levels greater than that of the upstream. Effluent data was observed at elevated levels during the period reviewed. It appears the discharge may be impacting downstream conductivity. Downstream turbidity was greater than 50 NTUs [per 15A NCAC 02B .0211 (21)] on one occasion during the period reviewed. Concurrent upstream turbidity was also observed at a level greater than 50 NTUs. It was concluded that a statistically significant difference exists between upstream and downstream turbidity. However, more often than not, upstream turbidity was observed at levels higher than downstream turbidity during the period reviewed, likely driving the statistically significant difference. It was concluded that a statistically significant difference exists between upstream and downstream ammonia, TP, TKN and NO2+NO3 with downstream values consistently higher than those of the upstream. Based on instream data review and discussions with the Division’s Basin Planning Branch, instream monitoring for TP, TKN, NO2+NO3, and ammonia have been added to the permit at a monthly frequency upstream and at D1 and D2 to capture the impact of the discharger and understand the influence of the confluence of Moadams Creek with Back Creek. Instream monitoring requirements for DO, temperature, fecal coliform and conductivity have been maintained. As the facility discharges to a zero flow stream, upstream hardness sampling has not been added to the permit at this time. Instream monitoring for 1,4-dioxane downstream at the Haw River at Old Greensboro Road and Old Bynum Bridge has been added at a monthly frequency. Please see Reasonable Potential Analysis (RPA) for Toxicants and Other WQBEL Considerations for more information. 5. Compliance Summary Summarize the compliance record with permit effluent limits (past 5 years): In 2018, the facility reported 1 BOD limit violation resulting in a Notice of Deficiency (NOD) and 4 ammonia limit violations resulting in Notices of Violation (NOVs). The facility reported 1 BOD limit violation resulting in an NOD in 2019. In 2020, the facility reported 2 DO limit violations resulting in NODs. Summarize the compliance record with aquatic toxicity test limits and any second species test results (past 5 years): The facility passed 24 of 27 quarterly chronic toxicity tests from January 2018 to September 2022. The facility reported failed toxicity tests in October 2018, July 2019, and July 2022. Page 5 of 20 Each of these cases were followed by 2 consecutive months of passing tests. In addition, the facility passed 4 of 4 second species tests from October 2017 to July 2018. Summarize the results from the most recent compliance inspection: The last facility inspection conducted in June 2022 reported that the facility was in compliance with NPDES permit NC0021474. The last pretreatment compliance inspection conducted in August 2021 reported that the facility was compliant with their pretreatment program. 6. Water Quality-Based Effluent Limitations (WQBELs) Dilution and Mixing Zones In accordance with 15A NCAC 2B.0206, the following streamflows are used for dilution considerations for development of WQBELs: 1Q10 streamflow (acute Aquatic Life); 7Q10 streamflow (chronic Aquatic Life; non-carcinogen HH); 30Q2 streamflow (aesthetics); annual average flow (carcinogen, HH). If applicable, describe any other dilution factors considered (e.g., based on CORMIX model results): NA If applicable, describe any mixing zones established in accordance with 15A NCAC 2B.0204(b): NA Oxygen-Consuming Waste Limitations Limitations for oxygen-consuming waste (e.g., BOD) are generally based on water quality modeling to ensure protection of the instream dissolved oxygen (DO) water quality standard. Secondary TBEL limits (e.g., BOD= 30 mg/l for Municipals) may be appropriate if deemed more stringent based on dilution and model results. If permit limits are more stringent than TBELs, describe how limits were developed: The current BOD limits are based on 15A NCAC 02B .0206 for discharges to zero-flow streams. While 15A NCAC 02B .0206 prohibits the introduction of new discharges to zero flow streams, it specifies that existing dischargers are to be assessed on a case-by-case basis. Cases are assessed alongside an engineering alternatives analysis (submitted by the City) and the resultant limit is a year-round BOD5 limit of 5 mg/L. This limit is proposed for the expanded 4.0 MGD and 6.0 MGD flow tiers. Ammonia and Total Residual Chlorine Limitations Limitations for ammonia are based on protection of aquatic life utilizing an ammonia chronic criterion of 1.0 mg/l (summer) and 1.8 mg/l (winter). Acute ammonia limits are derived from chronic criteria, utilizing a multiplication factor of 3 for Municipals and a multiplication factor of 5 for Non-Municipals. Limitations for Total Residual Chlorine (TRC) are based on the NC water quality standard for protection of aquatic life (17 ug/l) and capped at 28 ug/l (acute impacts). Due to analytical issues, all TRC values reported below 50 ug/l are considered compliant with their permit limit. Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: TRC limits have been reviewed in the attached WLA spreadsheet and have been found to be protective. TRC requirements have been assessed for the 4.0 MGD and 6.0 MGD flow tiers and a daily maximum limit of 17 ug/L has been applied for both expanded flow tiers. Please see Oxygen-Consuming Waste Limitations above for background on ammonia limits. The current ammonia limits are based on 15A NCAC 02B .0206 for discharges to zero-flow streams. Ammonia- nitrogen limits have been reviewed in the attached WLA. Based on toxicity-based calculations, ammonia limits of 1.0 mg/L and 1.8 mg/L were calculated for the summer and winter, respectively. These more restrictive limits are to be implemented upon expansion above 2.5 MGD. An additional 4.0 MGD and 6.0 Page 6 of 20 MGD flow tier has been incorporated in the permit with summer ammonia limits of 1.0 mg/L and 1.8 mg/L based on toxicity-based calculations performed in the attached WLA. Reasonable Potential Analysis (RPA) for Toxicants If applicable, conduct RPA analysis and complete information below. The need for toxicant limits is based upon a demonstration of reasonable potential to exceed water quality standards, a statistical evaluation that is conducted during every permit renewal utilizing the most recent effluent data for each outfall. The RPA is conducted in accordance with 40 CFR 122.44 (d) (i). The NC RPA procedure utilizes the following: 1) 95% Confidence Level/95% Probability; 2) assumption of zero background; 3) use of ½ detection limit for “less than” values; and 4) streamflows used for dilution consideration based on 15A NCAC 2B.0206. Effective April 6, 2016, NC began implementation of dissolved metals criteria in the RPA process in accordance with guidance titled NPDES Implementation of Instream Dissolved Metals Standards, dated June 10, 2016. Per Session Law 2012-187 Senate Bill 810 Section 12.1, “Rules adopted by the Environmental Management Commission pursuant to S.L. 2009-216 and S.L. 2009-486 to implement nutrient management strategies for the B. Everett Jordan Reservoir and the Falls of the Neuse Reservoir watersheds shall not be interpreted to apply surface water quality standards set out in 15A NCAC 2B .0218(3)(e) through (3)(h) to waters designated in the nutrient management rules as WS -V except where: (i) the designation of WS-V is associated with a water supply intake used by an industry to supply drinking water for their employees; or (ii) standards set out in 15A NCAC 02B .0218(3)(e) through (3)(h) are violated at the upstream boundary of waters within those watersheds that are classified as WS-II, WS- III, or WS-IV. This section shall not be construed to alter the nutrient reduction requirements set out in 15A NCAC 2B .0262(5) or 15A NCAC 2B .0275(3).” As the receiving stream: • was designated as WS-V as a result of the implementation of the nutrient management strategy for the B. Everett Jordan Reservoir; and • is not associated with a water supply intake used by an industry to supply drinking water for their employees; and • standards set out in 15A NCAC 02B .0218(3)(e) through (3)(h) are not violated at the upstream boundary of waters within those watersheds that are classified as WS-II, WS-III, or WS-IV; surface water quality standards set out in 15A NCAC 2B .0218(3)(e) through (3)(h) have not been applied to the RPA. Nitrate+Nitrite data collected at UCFRBA Monitoring Station B2000000 were assessed as a conservative estimate to track that the nitrate WS standard was not exceeded at the upper boundary of the nearest downstream WS-IV waters. UCFRBA Monitoring Station B2000000 is located approximately 1.2 miles upstream of the WS-IV boundary. Based on review of the data reported from January 2018 through December 2022 demonstrating a maximum reported Nitrate+Nitrite concentration at UCFRBA Monitoring Station B2000000 of 1.92 mg/L, it appears that the nitrate standard is met at the WS -IV boundary. While no data is available for Total Dissolved Solids (TDS) at the upper boundary of the nearest downstream WS-IV waters, the maximum reported TDS datum in the submitted effluent pollutant scans was 460 mg/L. As the allowable discharge concentration calculated considering the downstream WS-IV drinking water boundary is approximately 3,600 mg/L based on the 7Q10s of 58.7 cfs, it was concluded that no violation of the standard downstream would be caused by this discharge. Additionally, Total Dissolved Solids is not likely to transport in the receiving stream for the duration of stream length between the discharge point and WS-IV boundary. Page 7 of 20 To track that the narrative standard for 1,4-dioxane is not violated at the upstream boundary of the downstream WS-IV waters and at the Pittsboro drinking water intake, instream monitoring for 1,4- dioxane has been added to the permit downstream in the Haw River at Old Greensboro Road and Old Bynum Bridge. Should representative downstream 1,4-dioxane monitoring not be conducted by the Upper Cape Fear River Basin Association, downstream 1,4-dioxane monitoring requirements are immediately reinstated until confirmation of the coalition’s activation of such a sampling station is received by the Division. A reasonable potential analysis was conducted on effluent toxicant data collected between April 2018 through September 2022. Pollutants of concern included toxicants with positive detections and associated water quality standards/criteria. Based on this analysis, the following permitting actions are proposed for this permit: • Effluent Limit with Monitoring. The following parameters will receive a water quality-based effluent limit (WQBEL) since they demonstrated a reasonable potential to exceed applicable water quality standards/criteria: N/A • Monitoring Only. The following parameters will receive a monitor-only requirement since they did not demonstrate reasonable potential to exceed applicable water quality standards/criteria, but the maximum predicted concentration was >50% of the allowable concentration: Total Copper, Chlorides • No Limit or Monitoring: The following parameters will not receive a limit or monitoring, since they did not demonstrate reasonable potential to exceed applicable water quality standards/criteria and the maximum predicted concentration was <50% of the allowable concentration: Total Arsenic, Total Cadmium, Total Chromium, Total Cyanide, Total Lead, Total Molybdenum, Total Nickel, Total Selenium, Total Silver, Total Zinc • POTW Effluent Pollutant Scan Review: Four effluent pollutant scans were evaluated for additional pollutants of concern. o The following parameter(s) will receive a water quality-based effluent limit (WQBEL) with monitoring, since as part of a limited data set, two samples exceeded the allowable discharge concentration: N/A o The following parameter(s) will receive a monitor-only requirement, since as part of a limited data set, one sample exceeded the allowable discharge concentration: N/A o The following parameters will not receive a limit or monitoring, since they did not demonstrate reasonable potential to exceed applicable water quality standards/criteria and the maximum predicted concentration was <50% of the allowable concentration: Total Beryllium, Total Phenolic Compounds The City requests that the total zinc datapoint on 10/24/2019 be excluded from the RPA. The City provided the following justification: “On 10/21/2019, analysis on Digester #2 solids showed a pH of <6.0. Aeration was reduced immediately to raise the pH level, and Digester #1 solids with a pH >7.0 were transferred to Digester #2 (refer to Table 1 - Digester Monitoring Data attached). During this period, dewatering from Digester #2 was in process. The low pH conditions of Digester #2 had increased the availability of zinc in the belt press filtrate, which is returned to the plant headworks. Belt press filtrate samples from 10/21/2019-10/24/2019 were collected and sent for zinc analysis. The results began at 816 µg/L on 10/21/2019 and decreased to 204 µg/L on 10/24/2019 (refer to Report of Analysis dated 11/8/2019 by Research & Analytical Laboratories attached). The City analyzes zinc in both influent and effluent at least quarterly. During the 4.5-year RPA period, the effluent zinc analysis on 10/24/2019 is the only datapoint that was higher than the corresponding influent zinc analysis on 10/22/2019 (refer to Influent + Effluent Zinc Data chart attached). Definitively, the elevated effluent zinc datapoint was the result of the temporary upset condition in Digester #2 and, Page 8 of 20 though that effluent zinc level did not exceed the water quality standard, it is not representative of the characteristics of our waste stream.” Based on the justification provided by the City, the total zinc datapoint from 10/24/2019 was not included in the RPA. If applicable, attach a spreadsheet of the RPA results as well as a copy of the Dissolved Metals Implementation Fact Sheet for freshwater/saltwater to this Fact Sheet. Include a printout of the RPA Dissolved to Total Metal Calculator sheet if this is a Municipality with a Pretreatment Program. Toxicity Testing Limitations Permit limits and monitoring requirements for Whole Effluent Toxicity (WET) have been established in accordance with Division guidance (per WET Memo, 8/2/1999). Per WET guidance, all NPDES permits issued to Major facilities or any facility discharging “complex” wastewater (contains anything other than domestic waste) will contain appropriate WET limits and monitoring requirements, with several exceptions. The State has received prior EPA approval to use an Alternative WET Test Procedure in NPDES permits, using single concentration screening tests, with multiple dilution follow-up upon a test failure. Describe proposed toxicity test requirement: The permit requires quarterly chronic toxicity testing at 90% effluent concentration at 2.5 MGD. Quarterly chronic toxicity testing at 90% effluent concentration at 4.0 MGD and 6.0 MGD has been added to the permit. Mercury Statewide TMDL Evaluation There is a statewide TMDL for mercury approved by EPA in 2012. The TMDL target was to comply with EPA’s mercury fish tissue criteria (0.3 mg/kg) for human health protection. The TMDL established a wasteload allocation for point sources of 37 kg/year (81 lb/year), and is applicable to municipals and industrial facilities with known mercury discharges. Given the small contribution of mercury from point sources (~2% of total load), the TMDL emphasizes mercury minimization plans (MMPs) for point source control. Municipal facilities > 2 MGD and discharging quantifiable levels of mercury (>1 ng/l) will receive an MMP requirement. Industrials are evaluated on a case-by-case basis, depending if mercury is a pollutant of concern. Effluent limits may also be added if annual average effluent concentrations exceed the WQBEL value (based on the NC WQS of 12 ng/l) and/or if any individual value exceeds a TBEL value of 47 ng/l. Table 3. Mercury Effluent Data Summary (2.5 MGD) 2018 2019 2020 2021 2022 # of Samples 5 8 12 3 3 Annual Average Conc. ng/L 3.2 2.2 2.4 4.6 2.3 Maximum Conc., ng/L 6.21 3.61 4.82 10.2 3.38 TBEL, ng/L 47 WQBEL, ng/L 12.0 at all flow tiers Describe proposed permit actions based on mercury evaluation: Since no annual average mercury concentration exceeded the WQBEL, and no individual mercury sample exceeded the TBEL, no mercury limit is required. Since the facility is > 2 MGD and reported multiple detections (> 1 ng/L), a mercury minimization plan (MMP) is required. The MMP requirement will be maintained. Page 9 of 20 Other TMDL/Nutrient Management Strategy Considerations If applicable, describe any other TMDLs/Nutrient Management Strategies and their implementation within this permit: The facility lies in the Haw River arm of the Lake Jordan Reservoir. The Haw River arm is subject to the Jordan Water Supply Nutrient Strategy, 15A NCAC 02B .0262, in which are respective nitrogen and phosphorus TMDL reduction goals are 8 and 5% from 1997-2001 baseline load levels. To meet these goals, the facility is subject to nitrogen and phosphorus allocations assigned in accordance with the Jordan Water Supply Nutrient Strategy: Wastewater Discharge Requirements, 15A NCAC 02B .0270. The assigned allocations are listed in the current permit as load limits of 40,225 lb/yr total nitrogen (TN) and 5,056 lbs/yr total phosphorus (TP). Nutrient requirements were originally placed in the permit as a modification to incorporate Jordan Lake Nutrient Requirements (15A NCAC 02B .0270) on July 9, 2010. The 2010 permit modification included: monthly and annual TN and TP load monitoring requirements; an annual TP load limit of 5,056 lb/yr, effective 8/1/2010; and the addition of five special conditions. The added special conditions included: 1) nutrient allocations, 2) annual TN and TP limits, 3) calculation for TN and TP loads, 4) nitrogen optimization, and 5) a nutrient monitoring re-opener. A TN load limit of 40,225 lb/yr was added during the 2014 renewal with an effective date 1/1/2019 in recognition of the extension to implementation per Session Law 2016-94, H.B. 1030. Special Condition A.(3.) of the current permit lists TN and TP allocations assigned to the Mebane WWTP in accordance with the Jordan Lake Nutrient Management Rule. This special Condition states that for compliance purposes these allocations do not supersede any nutrient limit elsewhere in the permit or in a NPDES permit of a compliance association in which the Permittee is a Co-Permittee Member. The allocations are referred to as limits in Special Condition A. (6.) of the current permit. In addition, the TP allocation is the same as that in the Haw River Nutrient Compliance Association (HRNCA) NPDES Permit No. NCC000003 (issued December 22, 2016), of which Permittee is a Co-Permittee Member. Special Condition A.(4.) of the current permit contains a TN reduction schedule for the TN load limit which concluded in January 2021. As the schedule has concluded, Special Condition A.(4.) Total Nitrogen Reduction Schedule has been removed from the permit. Special Condition A.(5.) of the current permit contains requirement that the City follow the nitrogen optimization plan submitted to the Division on February 5, 2010. As the facility has taken measures to achieve compliance with total nitrogen limitations and requirements, Special Condition A.(5.) Nutrient Optimization has been removed from the permit. Special Condition A.(6.) of the current permit contains a nutrient monitoring reopener. As the Division may request additional monitoring for TN and TP if necessary, Special Condition A.(6.) Nutrient Monitoring Reopener has been removed from the permit. Special Condition A. (9.) of the current permit states that the Permittee shall be in compliance with TN and TP load limits if the load is less than the limit, or if the Permittee is a Co-Permittee Member of a compliance association. Review of effluent data showed annual TN and TP loads were below their respective limits for the calendar years 2018 through 2021 (see Table 1). As stated above, Mebane WWTP is a Co-Permittee Member of HRNCA, which addresses only TP discharges. TP allocations and effluent limits for Mebane WWTP are the same in the current permit as in the HRNCA permit. Therefore, compliance is demonstrated. Page 10 of 20 Special Condition A.(10.) of the current permit contains formulae to calculate monthly and annual nutrient (TN and TP) loading based on effluent concentrations and flows. To check TN load calculations, the current permit requires weekly monitoring of effluent TKN, NO2 + NO3 and TN concentrations as separate parameters. Review of submitted data found TN values (concentrations and loads) as well as TP loads to be properly calculated. As conditions have been removed, the numbering of the existing nutrient-related special conditions has been adjusted. Other WQBEL Considerations If applicable, describe any other parameters of concern evaluated for WQBELs: As required by Session Law 2018-5, Senate Bill 99, Section 13.1(r), every applicant shall submit documentation of any additional pollutants for which there are certified methods with the permit application if their discharge is anticipated. The City of Mebane informed the Division that no effluent monitoring for additional pollutants has been conducted (see attached chemical addendum) and therefore no additional pollutants of concern have been identified in their effluent. In 2019, based on the EPA’s Third Unregulated Contaminant Monitoring Rule indicating elevated concentrations of PFAS and 1,4-dioxane in the Cape Fear River Basin, the Division required facilities in the basin with pretreatment programs conduct investigative monitoring of their influents for PFAS and 1,4-dioxane. The City of Mebane found the presence of 1,4-dioxane in their Mebane WWTP influent samples. During the 2019 investigative study, the Mebane WWTP’s influent ranged from 1.38 µg/L to 1.51 µg/L. Influent concentration is anticipated to reflect effluent concentrations based on existing components at the treatment facility. As only 3 influent samples from 2019 are available for this parameter, further investigation into the concentrations of 1,4-dioxane present in the facility’s effluent is required to better characterize the waste. Per Session Law 2012 – 187 Section 12.1, the WS-V standards are not considered at the discharge point. However, the Pittsboro Intake WS-IV boundary exists approximately 21.5 miles downstream of Outfall 001. Please note that chronic allowable discharge concentrations have been calculated for this facility’s three effluent flow tiers. A comparison of allowable discharge concentrations has been made between the direct discharge to Moadams Creek under Class C requirements and the downstream Pittsboro Intake WS-IV boundary. Calculations for the allowable 1,4-Dioxane discharge concentration considering the downstream Pittsboro Intake WS-IV boundary are based on a Instream Target Value (ITV) for water supply waters of 80 µg/L and an annual average flow (AAF) of 0.8 cfs. These calculations resulted in chronic allowable discharge concentrations of 96.5 µg/L, 90.3 µg/L and 86.8 µg/L for the 2.5 MGD, 4.0 MGD and 6.0 MGD flow tiers, respectively. Calculations for the allowable discharge concentration considering the downstream Pittsboro Intake WS- IV boundary are based on a 1×10-6 risk level Instream Target Value (ITV) for water supply waters of 0.35 µg/L and an AAF of 1,150 cfs. These calculations resulted in chronic allowable discharge concentrations of 104.2 µg/L, 65.2 µg/L and 43.6 µg/L for the 2.5 MGD, 4.0 MGD and 6.0 MGD flow tiers, respectively. Page 11 of 20 Monthly effluent 1,4-dioxane monitoring and a 1,4-dioxane reopener condition have been added to the permit at all flow tiers. After 12 months of sampling, the Permittee may request the Division to evaluate submitted 1,4-dioxane data for approval of 1,4-dioxane monitoring frequency reduction from monthly to quarterly. To identify PFAS concentrations in waters classified as Water Supply (WS) waters, monitoring requirements are to be implemented in permits with pretreatment programs that discharge to WS waters. As the Mebane WWTP has a pretreatment program and discharges treated wastewater above waters designated as WS-IV, and as the City has identified the presence of PFAS in their influent based on the 2019 investigative monitoring for PFAS and 1,4-dioxane, monitoring of PFAS chemicals will be added to the permit at a frequency of quarterly. Since an EPA method for sampling and analyzing PFAS in wastewater is not currently available, the PFAS sampling requirement in the Permit includes a compliance schedule which delays the effective date of this requirement until the first full calendar quarter beginning 6 months after EPA has a final wastewater method in 40 CFR136 published in the Federal Register. This date may be extended upon request and if there are no NC-certified labs. If applicable, describe any special actions (HQW or ORW) this receiving stream and classification shall comply with in order to protect the designated waterbody: NA If applicable, describe any compliance schedules proposed for this permit renewal in accordance with 15A NCAC 2H.0107( c)(2)(B), 40CFR 122.47, and EPA May 2007 Memo: NA If applicable, describe any water quality standards variances proposed in accordance with NCGS 143- 215.3(e) and 15A NCAC 2B.0226 for this permit renewal: NA 7. Technology-Based Effluent Limitations (TBELs) Are concentration limits in the permit at least as stringent as secondary treatment requirements (30 mg/l BOD5/TSS for Monthly Average, and 45 mg/l for BOD5/TSS for Weekly Average). YES If NO, provide a justification for alternative limitations (e.g., waste stabilization pond). NA Are 85% removal requirements for BOD5/TSS included in the permit? YES If NO, provide a justification (e.g., waste stabilization pond). NA 8. Antidegradation Review (New/Expanding Discharge): The objective of an antidegradation review is to ensure that a new or increased pollutant loading will not degrade water quality. Permitting actions for new or expanding discharges require an antidegradation review in accordance with 15A NCAC 2B.0201. Each applicant for a new/expanding NPDES permit must document an effort to consider non-discharge alternatives per 15A NCAC 2H.0105( c)(2). In all cases, existing instream water uses and the level of water quality necessary to protect the existing use is maintained and protected. If applicable, describe the results of the antidegradation review, including the Engineering Alternatives Analysis (EAA) and any water quality modeling results: The proposed expansion is funded via the American Rescue Plan Act (ARPA) and is not subject to review under the National Environmental Policy Act (NEPA). As all funds ARPA are through the Wastewater Reserve, Drinking Water Reserve and/or the Viable Utility Reserve, the project is not subject to review under the State Environmental Policy Act (SEPA). An Engineer’s Alternatives Analysis (EAA) was submitted by McGill Associates, P.A. (McGill), the consulting firm hired by the City of Mebane, on April 5, 2022. The Division reviewed this EAA and supporting documentation and submitted an additional information request on October 6, 2022, asking for Page 12 of 20 further clarification regarding the conclusion of sending the additional flow to a neighboring facility as infeasible. The City noted that sending the proposed increased flow to any of the neighboring facilities would require those facilities to expand, pushing them to 80% of their design capacity or greater. After reviewing the analysis, Division staff concurred with the projected flow justification as well as the alternatives analysis. Division staff concurred with the projected flow needs based on a 20-year planning horizon. The Mebane WWTP treats wastewater for a population of approximately 18,000 residents. Based on the City’s 2017 Comprehensive Development Plan and the US 2020 Census, the City of Mebane experienced an increase in population from 2010 – 2020 of roughly 4.5% per year. The flow projections provided by McGill incorporate the expected municipal demand based on a linear extrapolation of the City’s population growth rather than the state projection method since the City is experiencing a more rapid growth pattern than the State. McGill projects demand out to 2061 in their report, with approximations of roughly 35,000 residents in 2041 and roughly 51,000 residents in 2061 . Division staff concurs with the modelled growth provided by McGill as it is consistent with the 2010 – 2020 North Carolina Office of State Budget and Management population growth extrapolated out to 2060. Flow projections consider 70 gallons per day (gpd) for residential use (2.4 MGD by 2041 and 3.6 MGD by 2061), 15 gpd for commercial flow (0.5 MGD by 2041 and 0.77 MGD by 2061) and constant industrial and institutional flows of 0.24 MGD and 0.08 MGD, respectively. Upon Division request, McGill provided additional information regarding flow projections and future flow demand on March 10, 2023. Based on these projections and Division review of Office of State Budget and Management (OSBM) data, the 4.0 MGD and 6.0 MGD expanded flow tiers are justifiable. The following alternatives were evaluated for the expanded flow: Alternative Description 20-year Net Present Value Connection to an Existing Public Sewer System 189,708,000 Land Application $180,469,000 Public Access Reuse N/A Combo of connection to existing sewer and land application $158,025,000 Expansion of facility $95,611,000 Connection to an Existing Public Sewer System: There are three existing municipal WWTPs within a five-mile radius of the Mebane WWTP: the Graham WWTP, the Burlington Eastside WWTP, and the Burlington Southside WWTP. The Graham WWTP currently operates at approximately 54% capacity. With the addition of 3.5 MGD from the City, the Graham WWTP would exceed its permitted hydraulic capacity of 3.5 MGD. For this reason, connecting the City's sewer collection system to solely the City of Graham's sewer collection system was deemed infeasible. The Burlington Eastside WWTP and Burlington Southside WWTP currently operate at approximately 38% and 67% capacity, respectively. The City of Burlington is under contract to accept a maximum of 5.844 MGD from seven regional municipalities and discharge a maximum of 0.9 MGD to the City of Greensboro. In 2020, the City of Burlington accepted an average of 2.3605 MGD from the seven municipalities and discharged an average of 0.1709 MGD to the City of Greensboro. It is not clear how much flow was accepted and discharged by each WWTP owned by the City of Burlington. In their initial submittal, McGill deemed the connection to an existing public sewer system infeasible due to a potential need to expand the subject facility. The Division requested additional justification for this assumption and further economic assessment of the alternative on October 6, 2022. On March 10, 2023, McGill provided additional information regarding this alternative. Page 13 of 20 It is unclear which Burlington WWTP (Eastside or Southside) receives the flows listed above; however, based on the proximity of these municipalities to the Burlington WWTPs, it was assumed that the Burlington Eastside WWTP receives flow from the City of Graham, Town of Green Level, Town of Elon, Town of Gibsonville, and Town of Haw River, while the Burlington Southside WWTP receives flow from the Town of Swepsonville and the Village of Alamance. Based on these assumptions, the Burlington Eastside WWTP is contracted to receive a maximum of 4.90 MGD from the surrounding municipalities, while the Burlington Southside WWTP is contracted to receive a maximum of 0.94 MGD from the surrounding municipalities. Discharging wastewater to the Burlington Eastside WWTP was considered because the facility is situated significantly closer to the Mebane WRRF (than the Burlington Southside WWTP) and discharged less flow in 2021 (than the Burlington Southside WWTP). According to the 2021 LWSP, the Burlington Eastside WWTP had an average annual daily discharge of 4.13 MGD and received an average of 2.12 MGD from the surrounding municipalities (assuming the Burlington Eastside WWTP received flows from the municipalities listed above). This indicates that 2.01 MGD of wastewater received by the Burlington Eastside WWTP was produced by the City of Burlington itself. Under these assumptions, the City of Burlington’s Eastside WWTP has an estimated 5.09 MGD of available capacity. The 2041 estimated flows to the Mebane WRRF range from 3.81 to 4.56 MGD, based on the two population sources, while the 2061 estimated flows range from 5.94 to 7.45 MGD. Considering the Mebane WRRF is currently permitted to discharge up to 2.5 MGD, and the 90% capacity threshold is 2.25 MGD, the City of Mebane is projected to lack 1.56 to 2.31 MGD of capacity by 2041 and 3.69 to 5.20 MGD of capacity by 2061. Assuming no growth within the City of Burlington, if the Burlington Eastside WWTP was to receive t he additional 1.56 to 2.31 MGD of flow from the City of Mebane (expected by 2041), the Burlington Eastside WWTP would operate at approximately 68.5% to 74.7% capacity. However, if the Burlington Eastside WWTP was to receive the additional 3.69 to 5.20 MGD of flow from the City of Mebane (expected by 2061), the Burlington Eastside WWTP would operate at approximately 86.2% to 98.8% capacity. Understanding that zero growth in Burlington is not probable, the City of Burlington would be forced to begin both the planning and construction phases of its Eastside WWTP much sooner than anticipated. The connection of the City of Mebane’s sewer collection system to the Burlington Eastside WWTP would include installing two sanitary sewer lift stations, two screening units, and approximately 33,000 LF of 30-inch DI force main. Due to existing infrastructure, the proposed force main would need to be installed by bore & jack under several NCDOT roads. Additionally, a horizontal directional drill would be required to install the force main under the Haw River. There is significant rock in the area of the Haw River, and costs could increase after geotechnical exploration work. Land Application: The expansion of the Mebane WRRF under Alternative 2 includes the installation of a 5-stage BNR process and denitrification filters (without advanced treatment) to treat 6.0 MGD of raw wastewater. Under this alternative, 2.5 MGD of treated effluent would continue to be discharged to Moadams Creek, as permitted under the existing Mebane WRRF individual NPDES permit. The remaining 3.5 MGD would be land applied to adequate farmland in Alamance County with a spray irrigation system. Assuming that the Mebane WRRF operates at maximum capacity, 24.5 MG of reuse water would be land applied on a weekly basis. For this analysis, it was assumed that land application could only occur 70% of the year, due to a variety of factors including excessively wet soils, crop harvesting, poor weather, etc. To account for this period where land application cannot occur, 35 MG of Page 14 of 20 reuse water were assumed to be handled in an average week. According to the USDA Natural Resources Conservation Service (NRCS) Web Soil Survey, the majority of soils within Alamance County are unsuitable for the disposal of wastewater by irrigation, primarily due to steep slopes, low adsorption rates, high groundwater tables and flooding issues. A hydraulic loading rate 1-inch per acre per week was used, resulting in approximately 1,289 acres of land required for this alternative. This alternative would require the installation of a 17.5 MG side-stream detention pond at the WRRF (for periods when the reuse water does not meet land application requirements), an effluent pump station that transfers the reuse water from the WRRF to the proposed land application sites, approximately 79,500 LF of 16-inch diameter reuse water piping, four (4) booster pump stations, four (4) reuse water storage tanks, and four (4) spray irrigation systems with irrigation pumps. Storage requirements for each land application site would be based on a water balance analysis. For the purpose of this EAA, three (3) 3 MG reuse water storage tanks and one (1) 0.75 MG reuse water storage tank were assumed to be required. Additionally, this alternative would require the purchase of all 1,486 acres of general farmland previously discussed. Land assessment values for Alamance County were utilized to determine an approximate cost of each parcel. Public Access Reuse: Reuse by a select group of customers, including industries and golf courses, was first investigated. A preliminary review of online information revealed no industries with sufficient space or need to utilize the reuse water; however, Alamance County is home to several golf courses. Assuming that 75% of each golf course's land requires irrigation, and that the golf courses already have ponds capable of storing the reuse water during periods unsuitable for irrigation, approximately 548 acres of turfgrass could be available for public access reuse. According to a report published by the United States Golf Association, golf courses in the southeastern United States use an average of 2.4 acre-feet of water per irrigated turf acre per year. As such, these three golf courses would be capable of utilizing an estimated 1,174,285 gallons of reuse water each day. A preliminary review of online GIS parcel data showed various parks and city-owned properties situated within city limits. Assuming that 75% of each park and city-owned property requires irrigation, approximately 381 acres of land could be available for public access reuse. Assuming an average of 2.4 acre-feet of water per irrigated turf acre per year, these parks and city-owned properties would be capable of utilizing an estimated 815,928 gallons of reuse water each day. From these calculations, the golf courses, parks and city-owned properties could use approximately 1,990,213 gallons of reuse water each day. Utility-owned properties could use approximately 1,990,213 gallons of reuse water each day. This alternative fails to utilize all 3.5 MGD of the reuse water; therefore, a supplemental public access reuse option was explored. An alternative to reuse by a select group of customers is reuse by residential customers. If the three aforementioned golf courses and larger users use all 1,990,213 gallons of reuse water each day, a maximum of 1,509,787 gallons of reuse water could be utilized by residential customers. Assuming that the reuse water is used for home irrigation, a conservative estimate of summer water usage is 0.75 inches of water per acre per week. With an average irrigation frequency of 70%, and an average lawn size of 0.25 acres, approximately 2,965 residential customers would be needed to utilize the remaining 1,509,787 gallons of reuse water. According to the population projections, the population of the City will reach 19,420 individuals by the end of 2022. Assuming that there are 2.48 individuals contributing to each sewer connection, there will be an estimated 7,830 residential sewer customers by the end of 2022. With the residential population projected to continually increase, there will be plenty of residential sewer customers available to utilize the reuse water for residential irrigation. Alternative 3 would require the construction of a distribution system on the scale of a potable water distribution system and would depend on a successful public outreach program. Due to the enormity of such a reuse distribution system, and the subsequent significant capital investment required for construction, Alternative 3 was considered cost prohibitive to implement, relative to a direct discharge alternative. For this reason, a preliminary estimate of cost was not prepared for Alternative 3. Page 15 of 20 Combination of connection to existing sewer and land application: As previously discussed in Alternative 1, in 2020, the Burlington WWTPs discharged a combined average of 10.4244 MGD to the Haw River. Additionally, the City of Burlington is contracted to accept a maximum of 5.844 MGD from seven regional municipalities and discharge a maximum of 0.9 MGD to the City of Greensboro. Assuming no growth within the City of Burlington and maximum contract limits are met, the Burlington WWTPs would operate at 15.3684 MGD, or approximately 64% capacity. With the addition of 2 MGD from the City, the Burlington WWTPs would operate at 17.3684 MGD, or approximately 72% capacity. This indicates that the City of Burlington could have the capacity to accept 2.0 MGD from the City. Due to its relatively low current operating capacity (38%), it was assumed that the Burlington Eastside WWTP would be capable of accepting all 2 MGD from the City. Approximately 31,000 LF of 12-inch raw wastewater piping would be required to convey wastewater from the Mebane WRRF to the Burlington Eastside WWTP. Additionally, there would need to be an administrative effort to develop an interlocal agreement between the City of Mebane and the City of Burlington. Such negotiation for a wholesale rate for raw sewer would likely be a lengthy process. For the purpose of this analysis, a capacity allowance of $8,290,000 was assumed based on the existing Graham/Mebane Wastewater Treatment Plant Intergovernmental Agreement. Additionally, the City of Mebane will pay its usage based on the formula as follows: total MGD sent by the City to the Burlington Eastside WWTP divided by the total MGD treated at the WWTP times the cost for treatment by MGD. As previously mentioned, this alternative also includes the land application of 1.5 MGD of reuse water to farmland within Alamance County. Assuming that the Mebane WRRF continues to discharge 2.5 MGD of treated effluent to Moadams Creek, that the Mebane WRRF operates at maximum capacity, and that the City of Burlington accepts the 2 MGD previously discussed, 10.5 MG of reuse water would require disposal on a weekly basis. Following the same calculation described in Alternative 2, it was assumed that land application can only occur 70% of the year. Thus, 15 MG of reuse water were assumed to be handled in an average week. With an estimated 1-inch per acre per week hydraulic loading rate, approximately 552 acres would be required for disposal by land application. A review of the Alamance County GIS database revealed two parcels of general farmland with a cumulative area of approximately 585 acres north of the Mebane WRRF. The expansion of the Mebane WRRF to 4.0 MGD would include expanding the headworks; repurposing one existing aeration basin as an EQ tank; repurposing one existing aeration basin for sludge storage; and installing an influent pump station, 5-stage BNR oxidation ditches, secondary clarifiers, a RAS/WAS pump station, tertiary filters, a chlorine contact basin with dechlorination and post-aeration chambers, chemical feed equipment, 16-inch diameter gravity discharge piping, 5-ft. diameter effluent manholes, yard piping, and all associated electrical equipment. Also, Alternative 4 would require the installation of a 7.5 MG side-stream detention pond at the WRRF, an effluent pump station with multiple sets of pumps, approximately 40,300 LF of 16-inch reuse water distribution piping, two (2) booster pump stations, two (2) reuse water storage tanks, and two (2) spray irrigation systems with irrigation pumps. Storage requirements for each land application site would be based on a water balance analysis. For the purpose of this EAA, two (2) 0.75 MG reuse water storage tanks were assumed to be required. Additionally, this alternative would require the purchase of all 585 acres of general farmland previously discussed. Expansion of Facility: The expansion of the Mebane WRRF to 6.0 MGD would include expanding the headworks; repurposing one existing aeration basin as an EQ tank; repurposing one existing aeration basin for sludge storage; and installing an influent pump station, 5-stage BNR oxidation ditches, secondary clarifiers, a RAS/WAS ·pump station, tertiary filters, a chlorine contact basin with dechlorination and post-aeration chambers, a granular activated carbon treatment train, chemical feed equipment, yard piping, and all associated electrical equipment. Page 16 of 20 Alternative 5 would require the construction of approximately 275 LF of 16-inch diameter gravity discharge piping and three (3) 5-ft. diameter effluent manholes. The proposed gravity discharge pipeline would transport the treated effluent from the proposed re-aeration chamber to an existing effluent manhole along Moadams Creek. From the existing manhole, the treated effluent would gravity flow through approximately 200 LF of existing 36-inch effluent discharge piping, one (1) additional existing effluent manhole, and one (1) existing Parshall flume before flowing into Moadams Creek. The proposed gravity discharge pipeline and effluent manholes would be situated on land owned by the City. Alternative 5 assumes that the expanded WRRF would be capable of meeting its approved NPDES permits and would comply with the reliability requirements specified in 15A NCAC 2H.0124. The most economically feasible and chosen option was the expansion of Mebane WWTP. The Division has reviewed the alternatives and concurs with this decision. 9. Antibacksliding Review: Sections 402(o)(2) and 303(d)(4) of the CWA and federal regulations at 40 CFR 122.44(l) prohibit backsliding of effluent limitations in NPDES permits. These provisions require effluent limitations in a reissued permit to be as stringent as those in the previous permit, with some exceptions where limitations may be relaxed (e.g., based on new information, increases in production may warrant less stringent TBEL limits, or WQBELs may be less stringent based on updated RPA or dilution). Are any effluent limitations less stringent than previous permit (YES/NO): NO; However, based on the reasonable potential analysis (RPA) showing no reasonable potential to violate state water quality standards, the monitoring requirement for total zinc has been removed from the permit. If YES, confirm that antibacksliding provisions are not violated: NA 10. Monitoring Requirements Monitoring frequencies for NPDES permitting are established in accordance with the following regulations and guidance: 1) State Regulation for Surface Water Monitoring, 15A NCAC 2B.0500; 2) NPDES Guidance, Monitoring Frequency for Toxic Substances (7/15/2010 Memo); 3) NPDES Guidance, Reduced Monitoring Frequencies for Facilities with Superior Compliance (10/22/2012 Memo); 4) Best Professional Judgement (BPJ). Per US EPA (Interim Guidance, 1996), monitoring requirements are not considered effluent limitations under Section 402(o) of the Clean Water Act, and therefore anti- backsliding prohibitions would not be triggered by reductions in monitoring frequencies. For instream monitoring, refer to Section 4. The City of Mebane was granted 2/week monitoring for ammonia and TSS during their 2014 renewal and additionally BOD and fecal coliform via a 2017 modification to their permit based on 2012 DWR Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally Performing Facilities. The City has requested continuation of this monitoring frequency reduction. The last three years of the facility’s data for these parameters have been reviewed in accordance with the criteria outlined in the guidance. Based on this review, reduced monitoring has been maintained for BOD, ammonia, fecal coliform and TSS for the 2.5 MGD flow tier. Monitoring frequencies shall be reverted to daily per 15A NCAC 02B .0508 when the facility is expanded above 2.5 MGD to sufficiently monitor treatment at the upgraded facility. The City may request modification to their permit at a later date to demonstrate the upgraded facility meets the 2012 guidance. Page 17 of 20 11. Electronic Reporting Requirements The US EPA NPDES Electronic Reporting Rule was finalized on December 21, 2015. Effective December 21, 2016, NPDES regulated facilities are required to submit Discharge Monitoring Reports (DMRs) electronically. While NPDES regulated facilities would initially be required to submit additional NPDES reports electronically effective December 21, 2020, EPA is proposing to extend this deadline from December 21, 2020, to December 21, 2025. This permit contains the requirements for electronic reporting, consistent with Federal requirements. The current compliance date will be extended if the implementation date is extended as a final regulation change in the federal register. 12.Summary of Proposed Permitting Actions: Table 4. Current Permit Conditions and Proposed Changes 2.5 MGD Parameter Current Permit Proposed Change Basis for Condition/Change Flow MA 2.5 MGD No change to 2.5 MGD flow tier; add 4.0 MGD and 6.0 MGD flow tier per modification request 15A NCAC 2B .0505 Total Monthly Flow Monitor and Report Monthly No change; apply to all flow tiers For calculation of TN and TP Loads BOD5 Summer: MA 5.0 mg/l WA 7.5 mg/l Monitor and Report 2/week Winter: MA 10.0 mg/l WA 15.0 mg/l Monitor and Report 2/week No change to 2.5MGD flow tier; @ 4.0 MGD & 6.0 MGD flow tiers (year-round): MA 5.0 mg/l WA 7.5 mg/l Monitor and Report Daily WQBEL; For 2.5 MGD flow tier - 15A NCAC 02B .0206; for 4.0 MGD and 6.0 MGD flow tiers – 2023 Speculative Limits/Level B model; Surface Water Monitoring, 2012 DWR Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally Performing Facilities; Reverts to 15A NCAC 2B. 0500 upon expansion NH3-N Summer: MA 2.0 mg/l WA 6.0 mg/l Monitor and Report 2/week Winter: MA 4.0 mg/l WA 12.0 mg/l Monitor and Report 2/week No change to 2.5MGD flow tier; @ 4.0 MGD & 6.0 MGD flow tiers: Summer: MA 1.0 mg/l WA 3.0 mg/l Monitor and Report Daily Winter: MA 1.8 mg/l WA 5.4 mg/l Monitor and Report Daily WQBEL. For 2.5 MGD flow tier - 15A NCAC 02B .0206; for 4.0 MGD and 6.0 MGD flow tiers – 2023 Speculative Limits/Level B model; Surface Water Monitoring, 2012 DWR Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally Performing Facilities; Reverts to 15A NCAC 2B. 0500 upon expansion TSS MA 30 mg/l WA 45 mg/l Monitor and Report 2/week No change to 2.5MGD flow tier; @ 4.0 MGD & 6.0 MGD flow tiers: MA 30.0 mg/l WA 45.0 mg/l Monitor and Report Daily TBEL. For 2.5 MGD flow tier - Secondary treatment standards/40 CFR 133 / 15A NCAC 2B .0406; for 4.0 MGD and 6.0 MGD flow tiers – 2023 Speculative Limits/Level B model; Surface Water Monitoring, 2012 DWR Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Page 18 of 20 Permits for Exceptionally Performing Facilities; Reverts to 15A NCAC 2B. 0500 upon expansion Fecal coliform MA 200 /100ml WA 400 /100ml Monitor and Report 2/week No change to 2.5MGD flow tier; @ 4.0 MGD & 6.0 MGD flow tiers: MA 200 /100ml WA 400 /100ml Daily monitoring WQBEL. For 2.5 MGD flow tier - State WQ standard, 15A NCAC 2B; for 4.0 MGD and 6.0 MGD flow tiers – 2023 Speculative Limits/Level B model; Surface Water Monitoring, 2012 DWR Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally Performing Facilities; Reverts to 15A NCAC 2B. 0500 upon expansion DO DA ≥ 6.0 mg/L Monitor and Report Daily No change; apply to all flow tiers WQBEL. For 2.5 MGD flow tier - State WQ standard, 15A NCAC 2B; for 4.0 MGD and 6.0 MGD flow tiers – 2023 Speculative Limits/Level B model; Surface Water Monitoring, 15A NCAC 2B. 0500 Temperature Monitor and Report Daily No change; apply to all flow tiers Surface Water Monitoring, 15A NCAC 2B. 0500 pH 6 – 9 SU Monitor and Report Daily No change; apply to all flow tiers WQBEL. State WQ standard, 15A NCAC 2B Total Residual Chlorine DM 17 ug/L Monitor and Report Daily No change; apply to all flow tiers WQBEL. 2022 WLA. Surface Water Monitoring, 15A NCAC 2B. 0500 Conductivity Monitor and Report Daily No change; apply to all flow tiers Surface Water Monitoring, 15A NCAC 2B. 0500 Total Hardness No requirement All flow tiers: Quarterly Effluent monitoring Hardness-dependent dissolved metals water quality standards approved in 2016; no upstream required due to zero flow stream TKN Monitor and Report Weekly No change; apply to all flow tiers For calculation of Total Nitrogen NO2+NO3 Monitor and Report Weekly No change; apply to all flow tiers For calculation of Total Nitrogen Total Nitrogen Monitor and Report Weekly No change; apply to all flow tiers Surface Water Monitoring, Jordan Lake Nutrient Management Strategy T15A NCAC 2B .0270 TN Load Monitor and Report Monthly (as lb/mo) Annual TN mass limit of 40,225 lb/yr No change; apply to all flow tiers WQBEL. Jordan Lake Nutrient Management Strategy T15A NCAC 2B .0270 Total Phosphorous Monitor and Report Monthly No change; apply to all flow tiers Surface Water Monitoring, Jordan Lake Nutrient Management Strategy T15A NCAC 2B .0270 Page 19 of 20 TP Load Monitor and Report Monthly (as lb/mo) Annual TP mass limit of 5,056 lb/yr No change; apply to all flow tiers WQBEL. Jordan Lake Nutrient Management Strategy T15A NCAC 2B .0270 Instream Monitoring Monitor and report at variable frequency for DO, temperature, fecal coliform and conductivity Add TKN, NO2+NO3, ammonia, and total phosphorous; Add 1,4- dioxane with no coalition waiver unless coalition conducts representative sampling Based on instream data review and discussions with the Division’s Basin Planning Branch – NSW; Cape Fear Basin Strategy; Session Law 2012-187 Total Zinc Monitor and Report Quarterly Remove requirement Based on RPA results; No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required Chlorides No requirement All flow tiers: Monitor and Report Quarterly Based on RPA results; No RP , Predicted Max ≥ 50% of Allowable Cw - apply Quarterly Monitoring Total Copper No requirement All flow tiers: Monitor and Report Quarterly Based on RPA results; No RP , Predicted Max ≥ 50% of Allowable Cw - apply Quarterly Monitoring PFAS No requirement All flow tiers: Add Quarterly monitoring with delayed implementation PT facility discharging above WS-V waters; Implementation delayed until after EPA certified method becomes available. 1,4-Dioxane No requirement All flow tiers: Add monthly monitoring and a reopener condition Surface Water Monitoring; Based on 2019 Investigation –1,4-dioxane present in influent Chronic Toxicity Chronic limit, 90% effluent No change; apply to all flow tiers WQBEL. No toxics in toxic amounts. 15A NCAC 2B Effluent Pollutant Scan Three times per permit cycle No change; conducted in 2025, 2026 and 2027 40 CFR 122 Total Nitrogen Reduction Schedule Special Condition A.(4.) Remove requirement Requirement expired in 2021 Nitrogen Optimization Special Condition A.(5.) Remove requirement Facility achieves consistent compliance with nutrient requirements and has demonstrated downward trend in total nitrogen since 2010. Nutrient Monitoring Reopener Special Condition A.(6.) Remove requirement Facility is conducting monitoring in accordance with Division-set requirements; Division may require additional monitoring without condition Mercury Minimization Plan (MMP) MMP Special Condition No change Consistent with 2012 Statewide Mercury TMDL Implementation; Municipality with Q < 2 MGD Electronic Reporting Electronic Reporting Special Condition No change In accordance with EPA Electronic Reporting Rule 2015. MGD – Million gallons per day, MA - Monthly Average, WA – Weekly Average, DM – Daily Max, QA – Quarterly Average, DA – Daily Average, AA – Annual Average Page 20 of 20 13. Public Notice Schedule: Permit to Public Notice: July xx, 2023 Per 15A NCAC 2H .0109 & .0111, The Division will receive comments for a period of 30 days following the publication date of the public notice. Any request for a public hearing shall be submitted to the Director within the 30 days comment period indicating the interest of the party filing such request and the reasons why a hearing is warranted. 14. NPDES Division Contact If you have any questions regarding any of the above information or on the attached permit, please contact Nick Coco at (919) 707-3609 or via email at nick.coco@deq.nc.gov. 15. Fact Sheet Addendum (if applicable): Were there any changes made since the Draft Permit was public noticed (Yes/No): NO If Yes, list changes and their basis below: NA 16. Fact Sheet Attachments (if applicable): • RPA Spreadsheet Summary • BOD and TSS Removal • Monitoring Reduction Frequency Spreadsheet • Dissolved Metals Implementation/Freshwater • Waste Load Allocation Spreadsheet • Mercury TMDL Spreadsheet • Toxicity Summary • Instream Monitoring Summary • Renewal Application Addendum • Total Zinc Exemption Justification REQUIRED DATA ENTRY Name WQS Type Chronic Modifier Acute PQL Units Facility Name Mebane WWTP Par01 Arsenic Aquactic Life C 150 FW 340 ug/L WWTP/WTP Class IV Par02 Arsenic Human Health Water Supply C 10 HH/WS N/A ug/L NPDES Permit NC0021474 Par03 Beryllium Aquatic Life NC 6.5 FW 65 ug/L Outfall 001 Par04 Cadmium Aquatic Life NC 1.3007 FW 8.0733 ug/L Flow, Qw (MGD)6.000 Par05 Chlorides Aquatic Life NC 230 FW mg/L Receiving Stream Moadams Creek Par06 Chlorinated Phenolic Compounds Water Supply NC 1 A ug/L HUC Number 03030002 Par07 Total Phenolic Compounds Aquatic Life NC 300 A ug/L Stream Class Par08 Chromium III Aquatic Life NC 277.4452 FW 2132.8905 ug/L Par09 Chromium VI Aquatic Life NC 11 FW 16 µg/L 7Q10s (cfs)0.00 Par10 Chromium, Total Aquatic Life NC N/A FW N/A µg/L 7Q10w (cfs)0.00 Par11 Copper Aquatic Life NC 19.2743 FW 28.0745 ug/L 30Q2 (cfs)0.00 Par12 Cyanide Aquatic Life NC 5 FW 22 10 ug/L QA (cfs)0.80 Par13 Fluoride Aquatic Life NC 1,800 FW ug/L 1Q10s (cfs)0.00 Par14 Lead Aquatic Life NC 9.4367 FW 242.1615 ug/L Effluent Hardness 71.2 mg/L (Avg)Par15 Mercury Aquatic Life NC 12 FW 0.5 ng/L Upstream Hardness 25 mg/L (Avg)Par16 Molybdenum Human Health NC 2000 HH ug/L Combined Hardness Chronic 71.2 mg/L Par17 Nickel Aquatic Life NC 90.2531 FW 812.5854 µg/L Combined Hardness Acute 71.2 mg/L Par18 Nickel Water Supply NC 25.0000 WS N/A µg/L Data Source(s)Par19 Selenium Aquatic Life NC 5 FW 56 ug/L Par20 Silver Aquatic Life NC 0.06 FW 1.7935 ug/L Par21 Zinc Aquatic Life NC 307.6352 FW 305.1392 ug/L Par22 Par23 Par24 Follow directions for data entry. In some cases a comment menu list the available choices or a dropdown menu will provide a list you may select from. Error message occur if data entry does not meet input criteria. To appy a Model IWC %: Once the "Flow, Qw (MGD)" and and the "CHRONIC DILUTION FACTOR = " values are entered, the 7Q10s (cfs) flow is calculated and displayed. Enter the calculated "7Q10s (cfs)" flow value in Table 1. Table 1. Project Information Table 2. Parameters of Concern Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators MAXIMUM DATA POINTS = 58 7Q10s used as conservative estimate for 30Q2. Per Session Law 2012-187 Section 12.1 - WS standards not applied at direct discharge WS-V; NSW CHECK IF HQW OR ORW WQS CHECK TO APPLY MODEL Apply WS Hardness WQC 21474 RPA, input 8/14/2023 REQUIRED DATA ENTRY Name WQS Type Chronic Modifier Acute PQL Units Facility Name Mebane WWTP Par01 Arsenic Aquactic Life C 150 FW 340 ug/L WWTP/WTP Class IV Par02 Arsenic Human Health Water Supply C 10 HH/WS N/A ug/L NPDES Permit NC0021474 Par03 Beryllium Aquatic Life NC 6.5 FW 65 ug/L Outfall 001 Par04 Cadmium Aquatic Life NC 1.3007 FW 8.0733 ug/L Flow, Qw (MGD)2.500 Par05 Chlorides Aquatic Life NC 230 FW mg/L Receiving Stream Moadams Creek Par06 Chlorinated Phenolic Compounds Water Supply NC 1 A ug/L HUC Number 03030002 Par07 Total Phenolic Compounds Aquatic Life NC 300 A ug/L Stream Class Par08 Chromium III Aquatic Life NC 277.4452 FW 2132.8905 ug/L Par09 Chromium VI Aquatic Life NC 11 FW 16 µg/L 7Q10s (cfs)0.00 Par10 Chromium, Total Aquatic Life NC N/A FW N/A µg/L 7Q10w (cfs)0.00 Par11 Copper Aquatic Life NC 19.2743 FW 28.0745 ug/L 30Q2 (cfs)0.00 Par12 Cyanide Aquatic Life NC 5 FW 22 10 ug/L QA (cfs)0.80 Par13 Fluoride Aquatic Life NC 1,800 FW ug/L 1Q10s (cfs)0.00 Par14 Lead Aquatic Life NC 9.4367 FW 242.1615 ug/L Effluent Hardness 71.2 mg/L (Avg)Par15 Mercury Aquatic Life NC 12 FW 0.5 ng/L Upstream Hardness 25 mg/L (Avg)Par16 Molybdenum Human Health NC 2000 HH ug/L Combined Hardness Chronic 71.2 mg/L Par17 Nickel Aquatic Life NC 90.2531 FW 812.5854 µg/L Combined Hardness Acute 71.2 mg/L Par18 Nickel Water Supply NC 25.0000 WS N/A µg/L Data Source(s)Par19 Selenium Aquatic Life NC 5 FW 56 ug/L Par20 Silver Aquatic Life NC 0.06 FW 1.7935 ug/L Par21 Zinc Aquatic Life NC 307.6352 FW 305.1392 ug/L Par22 Par23 Par24 Follow directions for data entry. In some cases a comment menu list the available choices or a dropdown menu will provide a list you may select from. Error message occur if data entry does not meet input criteria. To appy a Model IWC %: Once the "Flow, Qw (MGD)" and and the "CHRONIC DILUTION FACTOR = " values are entered, the 7Q10s (cfs) flow is calculated and displayed. Enter the calculated "7Q10s (cfs)" flow value in Table 1. Table 1. Project Information Table 2. Parameters of Concern Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators MAXIMUM DATA POINTS = 58 7Q10s used as conservative estimate for 30Q2. Per Session Law 2012-187 Section 12.1 - WS standards not applied at direct discharge WS-V; NSW CHECK IF HQW OR ORW WQS CHECK TO APPLY MODEL Apply WS Hardness WQC 21474 RPA, input 8/14/2023 REASONABLE POTENTIAL ANALYSIS H1 H2 Effluent Hardness Upstream Hardness Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 4/5/2018 71.4 71.4 Std Dev.22.1130 1 Default 25 25 Std Dev.N/A 2 5/10/2018 62.2 62.2 Mean 71.2025 2 Mean 25.0000 3 6/12/2018 65.9 65.9 C.V.0.3106 3 C.V.0.0000 4 7/19/2018 78 78 n 40 4 n 1 5 8/14/2018 65.9 65.9 10th Per value 60.00 mg/L 5 10th Per value 25.00 mg/L 6 9/27/2018 68.6 68.6 Average Value =71.20 mg/L 6 Average Value =25.00 mg/L 7 10/11/2018 64.5 64.5 Max. Value 196.00 mg/L 7 Max. Value 25.00 mg/L 8 11/29/2018 52.5 52.5 8 9 12/13/2018 48.9 48.9 9 10 1/10/2019 196 196 10 11 2/14/2019 65.3 65.3 11 12 3/21/2019 66 66 12 13 4/11/2019 63 63 13 14 5/16/2019 61.1 61.1 14 15 6/18/2019 77.6 77.6 15 16 7/9/2019 58.2 58.2 16 17 7/11/2019 69.8 69.8 17 18 8/15/2019 67.9 67.9 18 19 9/12/2019 65.3 65.3 19 20 10/24/2019 75.3 75.3 20 21 11/21/2019 77.2 77.2 21 22 1/16/2020 62.1 62.1 22 23 2/27/2020 65.4 65.4 23 24 3/19/2020 73.8 73.8 24 25 4/16/2020 78.5 78.5 25 26 5/14/2020 66.8 66.8 26 27 6/11/2020 61.4 61.4 27 28 7/23/2020 67.2 67.2 28 29 8/20/2020 62.8 62.8 29 30 9/10/2020 81.9 81.9 30 31 10/29/2020 71.6 71.6 31 32 11/17/2020 64 64 32 33 12/10/2020 60 60 33 34 1/14/2021 60 60 34 35 4/8/2021 64 64 35 36 7/15/2021 72 72 36 37 10/7/2021 96 96 37 38 1/13/2022 72 72 38 39 4/21/2022 88 88 39 40 7/21/2022 60 60 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 58 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 - 1 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par01 & Par02 Arsenic Date Data BDL=1/2DL Results 1 4/5/2018 <5 2.5 Std Dev.0.6852 2 7/19/2018 <5 2.5 Mean 2.0781 3 10/11/2018 <5 2.5 C.V.0.3297 4 11/29/2018 <5 2.5 n 32 5 12/13/2018 <5 2.5 6 1/10/2019 <5 2.5 Mult Factor =1.10 7 4/11/2019 <5 2.5 Max. Value 2.5 ug/L 8 7/9/2019 <5 2.5 Max. Pred Cw 2.8 ug/L 9 7/11/2019 <5 2.5 10 8/15/2019 <5 2.5 11 9/12/2019 <5 2.5 12 10/24/2019 <5 2.5 13 11/21/2019 <5 2.5 14 1/16/2020 <5 2.5 15 2/27/2020 <5 2.5 16 3/19/2020 <5 2.5 17 4/16/2020 <5 2.5 18 5/14/2020 <5 2.5 19 6/11/2020 <5 2.5 20 7/23/2020 <5 2.5 21 8/20/2020 <5 2.5 22 9/10/2020 <5 2.5 23 10/29/2020 <5 2.5 24 11/17/2020 <2 1 25 12/10/2020 <2 1 26 1/14/2021 <2 1 27 4/8/2021 <2 1 28 7/15/2021 <2 1 29 10/7/2021 <2 1 30 1/13/2022 <2 1 31 4/21/2022 <2 1 32 7/21/2022 <2 1 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 - 2 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par03 Par04 Beryllium Cadmium Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 4/21/2022 <0.5 0.25 Std Dev.0.1250 1 4/5/2018 <2 1 Std Dev.0.4107 2 1/25/2017 <1 0.5 Mean 0.4375 2 7/19/2018 <2 1 Mean 0.7313 3 7/13/2016 <1 0.5 C.V. (default)0.6000 3 10/11/2018 <2 1 C.V.0.5616 4 4/15/2015 <1 0.5 n 4 4 11/29/2018 <2 1 n 32 5 5 12/13/2018 <2 1 6 Mult Factor =2.59 6 1/10/2019 <2 1 Mult Factor =1.17 7 Max. Value 0.50 ug/L 7 4/11/2019 <2 1 Max. Value 1.000 ug/L 8 Max. Pred Cw 1.30 ug/L 8 7/9/2019 <2 1 Max. Pred Cw 1.170 ug/L 9 9 7/11/2019 <2 1 10 10 8/15/2019 <2 1 11 11 9/12/2019 <2 1 12 12 10/24/2019 <2 1 13 13 11/21/2019 <2 1 14 14 1/16/2020 <2 1 15 15 2/27/2020 <2 1 16 16 3/19/2020 <2 1 17 17 4/16/2020 <2 1 18 18 5/14/2020 <2 1 19 19 6/11/2020 <2 1 20 20 7/23/2020 <2 1 21 21 8/20/2020 <2 1 22 22 9/10/2020 <2 1 23 23 10/29/2020 <1 0.5 24 24 11/17/2020 <0.2 0.1 25 25 12/10/2020 <0.2 0.1 26 26 1/14/2021 <0.2 0.1 27 27 4/8/2021 <0.2 0.1 28 28 7/15/2021 <0.2 0.1 29 29 10/7/2021 <0.2 0.1 30 30 1/13/2022 <0.2 0.1 31 31 4/21/2022 <0.2 0.1 32 32 7/21/2022 <0.2 0.1 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 58 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 - 3 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par05 Par07 Chlorides Total Phenolic Compounds Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 4/5/2018 105 105 Std Dev.17.6360 1 4/21/2022 12 12 Std Dev.4.7500 2 7/19/2018 106 106 Mean 91.3 2 1/25/2017 <5 2.5 Mean 4.8750 3 10/11/2018 99.8 99.8 C.V.0.1932 3 7/13/2016 <5 2.5 C.V. (default)0.6000 4 11/29/2018 80.7 80.7 n 10 4 4/15/2015 <5 2.5 n 4 5 12/13/2018 90.5 90.5 5 6 1/10/2019 83.3 83.3 Mult Factor =1.2 6 Mult Factor =2.59 7 4/11/2019 57.5 57.5 Max. Value 115.0 mg/L 7 Max. Value 12.0 ug/L 8 7/9/2019 73.2 73.2 Max. Pred Cw 139.2 mg/L 8 Max. Pred Cw 31.1 ug/L 9 7/11/2019 102 102 9 10 8/15/2019 115 115 10 11 11 12 12 13 13 14 14 15 15 16 16 17 17 18 18 19 19 20 20 21 21 22 22 23 23 24 24 25 25 26 26 27 27 28 28 29 29 30 30 31 31 32 32 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 58 58 Use "PASTE SPECIAL-Values" then "COPY" . Maximum data points = 58 Use "PASTE SPECIAL-Values" then "COPY" . Maximum data points = 58 - 4 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par10 Pa11 Chromium, Total Copper Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 4/5/2018 <5 2.5 Std Dev.1.1067 1 4/5/2018 1 1 Std Dev.2.3480 2 7/19/2018 <5 2.5 Mean 2.2188 2 7/19/2018 4 4 Mean 2.3469 3 10/11/2018 <5 2.5 C.V.0.4988 3 10/11/2018 3 3 C.V.1.0005 4 11/29/2018 <5 2.5 n 32 4 11/29/2018 5 5 n 32 5 12/13/2018 7 7 5 12/13/2018 1 1 6 1/10/2019 <5 2.5 Mult Factor =1.15 6 1/10/2019 1 1 Mult Factor =1.28 7 4/11/2019 <5 2.5 Max. Value 7.0 µg/L 7 4/11/2019 2 2 Max. Value 11.90 ug/L 8 7/9/2019 <5 2.5 Max. Pred Cw 8.1 µg/L 8 7/9/2019 4 4 Max. Pred Cw 15.23 ug/L 9 7/11/2019 <5 2.5 9 7/11/2019 1 1 10 8/15/2019 <5 2.5 10 8/15/2019 8 8 11 9/12/2019 <5 2.5 11 9/12/2019 2 2 12 10/24/2019 <5 2.5 12 10/24/2019 2 2 13 11/21/2019 <5 2.5 13 11/21/2019 <1 0.5 14 1/16/2020 <5 2.5 14 1/16/2020 2 2 15 2/27/2020 <5 2.5 15 2/27/2020 2 2 16 3/19/2020 <5 2.5 16 3/19/2020 4 4 17 4/16/2020 <5 2.5 17 4/16/2020 2 2 18 5/14/2020 <5 2.5 18 5/14/2020 <2 1 19 6/11/2020 <5 2.5 19 6/11/2020 <2 1 20 7/23/2020 <5 2.5 20 7/23/2020 <2 1 21 8/20/2020 <5 2.5 21 8/20/2020 <2 1 22 9/10/2020 <5 2.5 22 9/10/2020 <2 1 23 10/29/2020 <5 2.5 23 10/29/2020 11.9 11.9 24 11/17/2020 <2 1 24 11/17/2020 <2 1 25 12/10/2020 <2 1 25 12/10/2020 <2 1 26 1/14/2021 <2 1 26 1/14/2021 <2 1 27 4/8/2021 <2 1 27 4/8/2021 3 3 28 7/15/2021 <2 1 28 7/15/2021 <2 1 29 10/7/2021 <2 1 29 10/7/2021 <2 1 30 1/13/2022 <2 1 30 1/13/2022 2.7 2.7 31 4/21/2022 <2 1 31 4/21/2022 2 2 32 7/21/2022 <2 1 32 7/21/2022 <2 1 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 58 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 - 5 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par12 Par14 Cyanide Lead Date Data BDL=1/2DL Results Date BDL=1/2DL Results 1 4/5/2018 <5 5 Std Dev.0.0000 1 4/5/2018 <5 2.5 Std Dev.1.0042 2 7/19/2018 <5 5 Mean 5.00 2 7/19/2018 <5 2.5 Mean 1.8844 3 10/11/2018 <5 5 C.V.0.0000 3 10/11/2018 <5 2.5 C.V.0.5329 4 11/29/2018 <5 5 n 31 4 11/29/2018 <5 2.5 n 32 5 12/13/2018 <5 5 5 12/13/2018 <5 2.5 6 1/10/2019 <5 5 Mult Factor =1.00 6 1/10/2019 <5 2.5 Mult Factor =1.16 7 4/11/2019 <5 5 Max. Value 5.0 ug/L 7 4/11/2019 <5 2.5 Max. Value 2.500 ug/L 8 7/11/2019 <5 5 Max. Pred Cw 5.0 ug/L 8 7/9/2019 <5 2.5 Max. Pred Cw 2.900 ug/L 9 8/15/2019 <5 5 9 7/11/2019 <5 2.5 10 9/12/2019 <5 5 10 8/15/2019 <5 2.5 11 10/24/2019 <5 5 11 9/12/2019 <5 2.5 12 11/21/2019 <5 5 12 10/24/2019 <5 2.5 13 1/16/2020 <5 5 13 11/21/2019 <5 2.5 14 2/27/2020 <5 5 14 1/16/2020 <5 2.5 15 3/19/2020 <5 5 15 2/27/2020 <5 2.5 16 4/16/2020 <5 5 16 3/19/2020 <5 2.5 17 5/14/2020 <5 5 17 4/16/2020 <5 2.5 18 6/11/2020 <5 5 18 5/14/2020 <5 2.5 19 7/23/2020 <5 5 19 6/11/2020 <5 2.5 20 8/20/2020 <5 5 20 7/23/2020 <5 2.5 21 9/10/2020 <5 5 21 8/20/2020 <5 2.5 22 10/29/2020 <5 5 22 9/10/2020 <5 2.5 23 11/17/2020 <5 5 23 10/29/2020 <5 2.5 24 12/10/2020 <5 5 24 11/17/2020 <0.5 0.25 25 1/14/2021 <5 5 25 12/10/2020 <0.5 0.25 26 4/8/2021 <5 5 26 1/14/2021 <0.5 0.25 27 7/15/2021 <5 5 27 4/8/2021 <0.5 0.25 28 10/7/2021 <5 5 28 7/15/2021 <0.5 0.25 29 1/13/2022 <5 5 29 10/7/2021 <0.5 0.25 30 4/21/2022 <5 5 30 1/13/2022 0.8 0.8 31 7/21/2022 <5 5 31 4/21/2022 <0.5 0.25 32 32 7/21/2022 <0.5 0.25 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 58 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 - 6 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par16 Par17 & Par18 Molybdenum Nickel Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 4/5/2018 37 37 Std Dev.80.1608 1 4/5/2018 <5 2.5 Std Dev.1.6199 2 7/19/2018 40 40 Mean 65.2813 2 7/19/2018 <5 2.5 Mean 3.4281 3 10/11/2018 431 431 C.V.1.2279 3 10/11/2018 <5 2.5 C.V.0.4725 4 11/29/2018 39 39 n 32 4 11/29/2018 7 7 n 32 5 12/13/2018 37 37 5 12/13/2018 <5 2.5 6 1/10/2019 30 30 Mult Factor =1.33 6 1/10/2019 <5 2.5 Mult Factor =1.14 7 4/11/2019 53 53 Max. Value 431.0 ug/L 7 4/11/2019 <5 2.5 Max. Value 8.0 µg/L 8 7/9/2019 131 131 Max. Pred Cw 573.2 ug/L 8 7/9/2019 <5 2.5 Max. Pred Cw 9.1 µg/L 9 7/11/2019 123 123 9 7/11/2019 6 6 10 8/15/2019 95 95 10 8/15/2019 <5 2.5 11 9/12/2019 109 109 11 9/12/2019 <5 2.5 12 10/24/2019 112 112 12 10/24/2019 <5 2.5 13 11/21/2019 24 24 13 11/21/2019 <5 2.5 14 1/16/2020 21 21 14 1/16/2020 <5 2.5 15 2/27/2020 14 14 15 2/27/2020 <5 2.5 16 3/19/2020 21 21 16 3/19/2020 <5 2.5 17 4/16/2020 8 8 17 4/16/2020 <5 2.5 18 5/14/2020 24 24 18 5/14/2020 <5 2.5 19 6/11/2020 85 85 19 6/11/2020 <5 2.5 20 7/23/2020 21 21 20 7/23/2020 <5 2.5 21 8/20/2020 81 81 21 8/20/2020 <5 2.5 22 9/10/2020 89 89 22 9/10/2020 <5 2.5 23 10/29/2020 26 26 23 10/29/2020 <5 2.5 24 11/17/2020 30 30 24 11/17/2020 3.6 3.6 25 12/10/2020 40 40 25 12/10/2020 2.5 2.5 26 1/14/2021 26 26 26 1/14/2021 5.6 5.6 27 4/8/2021 22 22 27 4/8/2021 6 6 28 7/15/2021 37 37 28 7/15/2021 6.3 6.3 29 10/7/2021 205 205 29 10/7/2021 4.9 4.9 30 1/13/2022 17 17 30 1/13/2022 4 4 31 4/21/2022 21 21 31 4/21/2022 3.3 3.3 32 7/21/2022 40 40 32 7/21/2022 8 8 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 58 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 Use "PASTE SPECIAL-Values" then "COPY" . Maximum data points = 58 - 7 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par19 Par20 Selenium Silver Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 4/5/2018 <5 2.5 Std Dev.0.9136 1 4/5/2018 <1 0.5 Std Dev.0.1142 2 7/19/2018 <5 2.5 Mean 1.9375 2 7/19/2018 <1 0.5 Mean 0.4297 3 10/11/2018 <5 2.5 C.V.0.4715 3 10/11/2018 <1 0.5 C.V.0.2658 4 11/29/2018 <5 2.5 n 32 4 11/29/2018 <1 0.5 n 32 5 12/13/2018 <5 2.5 5 12/13/2018 <1 0.5 6 1/10/2019 <5 2.5 Mult Factor =1.14 6 1/10/2019 <1 0.5 Mult Factor =1.08 7 4/11/2019 <5 2.5 Max. Value 2.5 ug/L 7 4/11/2019 <1 0.5 Max. Value 0.500 ug/L 8 7/9/2019 <5 2.5 Max. Pred Cw 2.9 ug/L 8 7/9/2019 <1 0.5 Max. Pred Cw 0.540 ug/L 9 7/11/2019 <5 2.5 9 7/11/2019 <1 0.5 10 8/15/2019 <5 2.5 10 8/15/2019 <1 0.5 11 9/12/2019 <5 2.5 11 9/12/2019 <1 0.5 12 10/24/2019 <5 2.5 12 10/24/2019 <1 0.5 13 11/21/2019 <5 2.5 13 11/21/2019 <1 0.5 14 1/16/2020 <5 2.5 14 1/16/2020 <1 0.5 15 2/27/2020 <5 2.5 15 2/27/2020 <1 0.5 16 3/19/2020 <5 2.5 16 3/19/2020 <1 0.5 17 4/16/2020 <5 2.5 17 4/16/2020 <1 0.5 18 5/14/2020 <5 2.5 18 5/14/2020 <1 0.5 19 6/11/2020 <5 2.5 19 6/11/2020 <1 0.5 20 7/23/2020 <5 2.5 20 7/23/2020 <1 0.5 21 8/20/2020 <5 2.5 21 8/20/2020 <1 0.5 22 9/10/2020 <5 2.5 22 9/10/2020 <1 0.5 23 10/29/2020 <5 2.5 23 10/29/2020 <1 0.5 24 11/17/2020 <1 0.5 24 11/17/2020 <0.5 0.25 25 12/10/2020 <1 0.5 25 12/10/2020 <0.5 0.25 26 1/14/2021 <1 0.5 26 1/14/2021 <0.5 0.25 27 4/8/2021 <1 0.5 27 4/8/2021 <0.5 0.25 28 7/15/2021 <1 0.5 28 7/15/2021 <0.5 0.25 29 10/7/2021 <1 0.5 29 10/7/2021 <0.5 0.25 30 1/13/2022 <1 0.5 30 1/13/2022 <0.5 0.25 31 4/21/2022 <1 0.5 31 4/21/2022 <0.5 0.25 32 7/21/2022 <1 0.5 32 7/21/2022 <0.5 0.25 33 33 34 34 35 35 36 36 37 37 38 38 39 39 40 40 41 41 42 42 43 43 44 44 45 45 46 46 47 47 48 48 49 49 50 50 51 51 52 52 53 53 54 54 55 55 56 56 57 57 58 58 Use "PASTE SPECIAL-Values" then "COPY" . Maximum data points = 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 - 8 - 21474 RPA, data 8/14/2023 REASONABLE POTENTIAL ANALYSIS Par21 Zinc Date Data BDL=1/2DL Results 1 4/5/2018 66 66 Std Dev.17.6786 2 7/19/2018 50 50 Mean 42.5355 3 10/11/2018 70 70 C.V.0.4156 4 11/29/2018 14 14 n 31 5 12/13/2018 31 31 6 1/10/2019 62 62 Mult Factor =1.13 7 4/11/2019 50 50 Max. Value 81.0 ug/L 8 7/9/2019 58 58 Max. Pred Cw 91.5 ug/L 9 7/11/2019 81 81 10 8/15/2019 50 50 11 9/12/2019 68 68 12 11/21/2019 61 61 13 1/16/2020 48 48 14 2/27/2020 40 40 15 3/19/2020 50 50 16 4/16/2020 22 22 17 5/14/2020 53 53 18 6/11/2020 28 28 19 7/23/2020 41 41 20 8/20/2020 36 36 21 9/10/2020 38 38 22 10/29/2020 35.1 35.1 23 11/17/2020 24 24 24 12/10/2020 21 21 25 1/14/2021 31 31 26 4/8/2021 48 48 27 7/15/2021 26 26 28 10/7/2021 39 39 29 1/13/2022 39 39 30 4/21/2022 <5 2.5 31 7/21/2022 36 36 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 Use "PASTE SPECIAL- Values" then "COPY" . Maximum data points = 58 - 9 - 21474 RPA, data 8/14/2023 Mebane WWTP ≥Outfall 001 NC0021474 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 2.5 MGD MAXIMUM DATA POINTS = 58 Qw (MGD) = 2.5000 WWTP/WTP Class:IV COMBINED HARDNESS (mg/L) 1Q10S (cfs) = 0.00 IWC% @ 1Q10S = 100 Acute = 71.2 mg/L 7Q10S (cfs) = 0.00 IWC% @ 7Q10S = 100 Chronic = 71.2 mg/L 7Q10W (cfs) = 0.00 IWC% @ 7Q10W = 100 30Q2 (cfs) = 0.00 IWC% @ 30Q2 = 100 Avg. Stream Flow, QA (cfs) = 0.80 IW%C @ QA = 82.88770053 Receiving Stream:Stream Class:WS-V; NSW PARAMETER RECOMMENDED ACTION Chronic Applied Standard Acute n # Det.Max Pred Cw Acute (FW):340.0 Arsenic C 150 FW 340 ug/L 32 0 2.8 Chronic (FW):150.0 Max MDL = 5 Arsenic C 10 HH/WS ug/L NO DETECTS Chronic (HH):12.1 Max MDL = 5 Acute:65.00 Beryllium NC 6.5 FW 65 ug/L 4 0 1.30 Note: n ≤ 9 C.V. (default)Chronic:6.50 Limited data set NO DETECTS Max MDL = 1 Acute:8.073 Cadmium NC 1.3007 FW 8.0733 ug/L 32 0 1.170 Chronic:1.301 NO DETECTS Max MDL = 2 Acute:NO WQS Chlorides NC 230 FW mg/L 10 10 139.2 Chronic:230.0 No value > Allowable Cw Acute:NO WQS Total Phenolic Compounds NC 300 A ug/L 4 1 31.1 Note: n ≤ 9 C.V. (default)Chronic:300.0 Limited data set No value > Allowable Cw Acute:2,132.9 Chromium III NC 277.4452 FW 2132.8905 µg/L 0 0 N/A Chronic:277.4 Acute:16.0 Chromium VI NC 11 FW 16 µg/L 0 0 N/A Chronic:11.0 Tot Cr value(s) ≥ 5 but < Cr VI Allowable Cw Chromium, Total NC µg/L 32 1 8.1 Acute:28.07 Copper NC 19.2743 FW 28.0745 ug/L 32 20 15.23 Chronic:19.27 No value > Allowable Cw Max reported value = 7 No RP , Predicted Max ≥ 50% of Allowable Cw - defer to LTMP a: No monitoring required if all Total Chromium samples are < 5 µg/L or Pred. max for Total Cr is < allowable Cw for Cr VI. No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required All values non-detect < 2 ug/L, < 1 ug/L and < 0.2 ug/L; No monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP , Predicted Max ≥ 50% of Allowable Cw - apply Quarterly MonitoringPQLUNITSTYPE Allowable Cw REASONABLE POTENTIAL RESULTSNC STANDARDS OR EPA CRITERIA Moadams Creek HUC 03030002 Page 1 of 2 21474 RPA, rpa 8/14/2023 Mebane WWTP ≥Outfall 001 NC0021474 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 2.5 MGD Acute:22.0 Cyanide NC 5 FW 22 10 ug/L 31 0 5.0 Chronic:5.0 NO DETECTS Max MDL = 10 Acute:242.161 Lead NC 9.4367 FW 242.1615 ug/L 32 1 2.900 Chronic:9.437 No value > Allowable Cw Acute:NO WQS Molybdenum NC 2000 HH ug/L 32 32 573.2 Chronic:2,000.0 No value > Allowable Cw Acute (FW):812.6 Nickel NC 90.2531 FW 812.5854 µg/L 32 11 9.1 Chronic (FW):90.3 No value > Allowable Cw Nickel NC 25.0000 WS µg/L Chronic (WS):25.0 No value > Allowable Cw Acute:56.0 Selenium NC 5 FW 56 ug/L 32 0 2.9 Chronic:5.0 NO DETECTS Max MDL = 5 Acute:1.794 Silver NC 0.06 FW 1.7935 ug/L 32 0 0.540 Chronic:0.060 NO DETECTS Max MDL = 1 Acute:305.1 Zinc NC 307.6352 FW 305.1392 ug/L 31 30 91.5 Chronic:307.6 No value > Allowable Cw No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required All values non-detect < 1ug/L and < 0.5 ug/L; No monitoring required All values non-detect < 5ug/L and < 1 ug/L; No monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required All values non-detect < 5ug/L ; No monitoring required Page 2 of 2 21474 RPA, rpa 8/14/2023 Mebane WWTP ≥Outfall 001 NC0021474 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 6 MGD MAXIMUM DATA POINTS = 58 Qw (MGD) = 6.0000 WWTP/WTP Class:IV COMBINED HARDNESS (mg/L) 1Q10S (cfs) = 0.00 IWC% @ 1Q10S = 100 Acute = 71.2 mg/L 7Q10S (cfs) = 0.00 IWC% @ 7Q10S = 100 Chronic = 71.2 mg/L 7Q10W (cfs) = 0.00 IWC% @ 7Q10W = 100 30Q2 (cfs) = 0.00 IWC% @ 30Q2 = 100 Avg. Stream Flow, QA (cfs) = 0.80 IW%C @ QA = 92.07920792 Receiving Stream:Stream Class:WS-V; NSW PARAMETER RECOMMENDED ACTION Chronic Applied Standard Acute n # Det.Max Pred Cw Acute (FW):340.0 Arsenic C 150 FW 340 ug/L 32 0 2.8 Chronic (FW):150.0 Max MDL = 5 Arsenic C 10 HH/WS ug/L NO DETECTS Chronic (HH):10.9 Max MDL = 5 Acute:65.00 Beryllium NC 6.5 FW 65 ug/L 4 0 1.30 Note: n ≤ 9 C.V. (default)Chronic:6.50 Limited data set NO DETECTS Max MDL = 1 Acute:8.073 Cadmium NC 1.3007 FW 8.0733 ug/L 32 0 1.170 Chronic:1.301 NO DETECTS Max MDL = 2 Acute:NO WQS Chlorides NC 230 FW mg/L 10 10 139.2 Chronic:230.0 No value > Allowable Cw Acute:NO WQS Total Phenolic Compounds NC 300 A ug/L 4 1 31.1 Note: n ≤ 9 C.V. (default)Chronic:300.0 Limited data set No value > Allowable Cw Acute:2,132.9 Chromium III NC 277.4452 FW 2132.8905 µg/L 0 0 N/A Chronic:277.4 Acute:16.0 Chromium VI NC 11 FW 16 µg/L 0 0 N/A Chronic:11.0 Tot Cr value(s) ≥ 5 but < Cr VI Allowable Cw Chromium, Total NC µg/L 32 1 8.1 Acute:28.07 Copper NC 19.2743 FW 28.0745 ug/L 32 20 15.23 Chronic:19.27 No value > Allowable Cw Max reported value = 7 No RP , Predicted Max ≥ 50% of Allowable Cw - defer to LTMP a: No monitoring required if all Total Chromium samples are < 5 µg/L or Pred. max for Total Cr is < allowable Cw for Cr VI. No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required All values non-detect < 2 ug/L, < 1 ug/L and < 0.2 ug/L; No monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP , Predicted Max ≥ 50% of Allowable Cw - apply Quarterly MonitoringPQLUNITSTYPE Allowable Cw REASONABLE POTENTIAL RESULTSNC STANDARDS OR EPA CRITERIA Moadams Creek HUC 03030002 Page 1 of 2 21474 RPA, rpa 8/14/2023 Mebane WWTP ≥Outfall 001 NC0021474 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 6 MGD Acute:22.0 Cyanide NC 5 FW 22 10 ug/L 31 0 5.0 Chronic:5.0 NO DETECTS Max MDL = 10 Acute:242.161 Lead NC 9.4367 FW 242.1615 ug/L 32 1 2.900 Chronic:9.437 No value > Allowable Cw Acute:NO WQS Molybdenum NC 2000 HH ug/L 32 32 573.2 Chronic:2,000.0 No value > Allowable Cw Acute (FW):812.6 Nickel NC 90.2531 FW 812.5854 µg/L 32 11 9.1 Chronic (FW):90.3 No value > Allowable Cw Nickel NC 25.0000 WS µg/L Chronic (WS):25.0 No value > Allowable Cw Acute:56.0 Selenium NC 5 FW 56 ug/L 32 0 2.9 Chronic:5.0 NO DETECTS Max MDL = 5 Acute:1.794 Silver NC 0.06 FW 1.7935 ug/L 32 0 0.540 Chronic:0.060 NO DETECTS Max MDL = 1 Acute:305.1 Zinc NC 307.6352 FW 305.1392 ug/L 31 30 91.5 Chronic:307.6 No value > Allowable Cw No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required All values non-detect < 1ug/L and < 0.5 ug/L; No monitoring required All values non-detect < 5ug/L and < 1 ug/L; No monitoring required No RP, Predicted Max < 50% of Allowable Cw - No Monitoring required All values non-detect < 5ug/L ; No monitoring required Page 2 of 2 21474 RPA, rpa 8/14/2023 Permit No. NC0021474 Page 1 of 4 NPDES Implementation of Instream Dissolved Metals Standards – Freshwater Standards The NC 2007-2015 Water Quality Standard (WQS) Triennial Review was approved by the NC Environmental Management Commission (EMC) on November 13, 2014. The US EPA subsequently approved the WQS revisions on April 6, 2016, with some exceptions. Therefore, metal limits in draft permits out to public notice after April 6, 2016 must be calculated to protect the new standards - as approved. Table 1. NC Dissolved Metals Water Quality Standards/Aquatic Life Protection Parameter Acute FW, µg/l (Dissolved) Chronic FW, µg/l (Dissolved) Acute SW, µg/l (Dissolved) Chronic SW, µg/l (Dissolved) Arsenic 340 150 69 36 Beryllium 65 6.5 --- --- Cadmium Calculation Calculation 40 8.8 Chromium III Calculation Calculation --- --- Chromium VI 16 11 1100 50 Copper Calculation Calculation 4.8 3.1 Lead Calculation Calculation 210 8.1 Nickel Calculation Calculation 74 8.2 Silver Calculation 0.06 1.9 0.1 Zinc Calculation Calculation 90 81 Table 1 Notes: 1. FW= Freshwater, SW= Saltwater 2. Calculation = Hardness dependent standard 3. Only the aquatic life standards listed above are expressed in dissolved form. Aquatic life standards for Mercury and selenium are still expressed as Total Recoverable Metals due to bioaccumulative concerns (as are all human health standards for all metals). It is still necessary to evaluate total recoverable aquatic life and human health standards listed in 15A NCAC 2B.0200 (e.g., arsenic at 10 µg/l for human health protection; cyanide at 5 µg/L and fluoride at 1.8 mg/L for aquatic life protection). Table 2. Dissolved Freshwater Standards for Hardness-Dependent Metals The Water Effects Ratio (WER) is equal to one unless determined otherwise under 15A NCAC 02B .0211 Subparagraph (11)(d) Metal NC Dissolved Standard, µg/l Cadmium, Acute WER*{1.136672-[ln hardness](0.041838)} ∙ e^{0.9151 [ln hardness]-3.1485} Cadmium, Acute Trout waters WER*{1.136672-[ln hardness](0.041838)} ∙ e^{0.9151[ln hardness]-3.6236} Cadmium, Chronic WER*{1.101672-[ln hardness](0.041838)} ∙ e^{0.7998[ln hardness]-4.4451} Chromium III, Acute WER*0.316 ∙ e^{0.8190[ln hardness]+3.7256} Chromium III, Chronic WER*0.860 ∙ e^{0.8190[ln hardness]+0.6848} Copper, Acute WER*0.960 ∙ e^{0.9422[ln hardness]-1.700} Copper, Chronic WER*0.960 ∙ e^{0.8545[ln hardness]-1.702} Lead, Acute WER*{1.46203-[ln hardness](0.145712)} ∙ e^{1.273[ln hardness]-1.460} Lead, Chronic WER*{1.46203-[ln hardness](0.145712)} ∙ e^{1.273[ln hardness]-4.705} Nickel, Acute WER*0.998 ∙ e^{0.8460[ln hardness]+2.255} Nickel, Chronic WER*0.997 ∙ e^{0.8460[ln hardness]+0.0584} Permit No. NC0021474 Page 2 of 4 Silver, Acute WER*0.85 ∙ e^{1.72[ln hardness]-6.59} Silver, Chronic Not applicable Zinc, Acute WER*0.978 ∙ e^{0.8473[ln hardness]+0.884} Zinc, Chronic WER*0.986 ∙ e^{0.8473[ln hardness]+0.884} General Information on the Reasonable Potential Analysis (RPA) The RPA process itself did not change as the result of the new metals standards. However, application of the dissolved and hardness-dependent standards requires additional consideration in order to establish the numeric standard for each metal of concern of each individual discharge. The hardness-based standards require some knowledge of the effluent and instream (upstream) hardness and so must be calculated case-by-case for each discharge. Metals limits must be expressed as ‘total recoverable’ metals in accordance with 40 CFR 122.45(c). The discharge-specific standards must be converted to the equivalent total values for use in the RPA calculations. We will generally rely on default translator values developed for each metal (more on that below), but it is also possible to consider case-specific translators developed in accordance with established methodology. RPA Permitting Guidance/WQBELs for Hardness-Dependent Metals - Freshwater The RPA is designed to predict the maximum likely effluent concentrations for each metal of concern, based on recent effluent data, and calculate the allowable effluent concentrations, based on applicable standards and the critical low-flow values for the receiving stream. If the maximum predicted value is greater than the maximum allowed value (chronic or acute), the discharge has reasonable potential to exceed the standard, which warrants a permit limit in most cases. If monitoring for a particular pollutant indicates that the pollutant is not present (i.e. consistently below detection level), then the Division may remove the monitoring requirement in the reissued permit. 1. To perform a RPA on the Freshwater hardness-dependent metals the Permit Writer compiles the following information: • Critical low flow of the receiving stream, 7Q10 (the spreadsheet automatically calculates the 1Q10 using the formula 1Q10 = 0.843 (s7Q10, cfs) 0.993 • Effluent hardness and upstream hardness, site-specific data is preferred • Permitted flow • Receiving stream classification 2. In order to establish the numeric standard for each hardness-dependent metal of concern and for each individual discharge, the Permit Writer must first determine what effluent and instream (upstream) hardness values to use in the equations. The permit writer reviews DMR’s, Effluent Pollutant Scans, and Toxicity Test results for any hardness data and contacts the Permittee to see if any additional data is available for instream hardness values, upstream of the discharge. If no hardness data is available, the permit writer may choose to do an initial evaluation using a default hardness of 25 mg/L (CaCO3 or (Ca + Mg)). Minimum and maximum limits on the hardness value used for water quality calculations are 25 mg/L and 400 mg/L, respectively. If the use of a default hardness value results in a hardness-dependent metal showing reasonable potential, the permit writer contacts the Permittee and requests 5 site-specific effluent and upstream hardness samples over a period of one week. The RPA is rerun using the new data. Permit No. NC0021474 Page 3 of 4 The overall hardness value used in the water quality calculations is calculated as follows: Combined Hardness (chronic) = (Permitted Flow, cfs *Avg. Effluent Hardness, mg/L) + (s7Q10, cfs *Avg. Upstream Hardness, mg/L) (Permitted Flow, cfs + s7Q10, cfs) The Combined Hardness for acute is the same but the calculation uses the 1Q10 flow. 3. The permit writer converts the numeric standard for each metal of concern to a total recoverable metal, using the EPA Default Partition Coefficients (DPCs) or site-specific translators, if any have been developed using federally approved methodology. 4. The numeric standard for each metal of concern is divided by the default partition coefficient (or site-specific translator) to obtain a Total Recoverable Metal at ambient conditions. In some cases, where an EPA default partition coefficient translator does not exist (ie. silver), the dissolved numeric standard for each metal of concern is divided by the EPA conversion factor to obtain a Total Recoverable Metal at ambient conditions. This method presumes that the metal is dissolved to the same extent as it was during EPA’s criteria development for metals. For more information on conversion factors see the June, 1996 EPA Translator Guidance Document. 5. The RPA spreadsheet uses a mass balance equation to determine the total allowable concentration (permit limits) for each pollutant using the following equation: Ca = (s7Q10 + Qw) (Cwqs) – (s7Q10) (Cb) Qw Where: Ca = allowable effluent concentration (µg/L or mg/L) Cwqs = NC Water Quality Standard or federal criteria (µg/L or mg/L) Cb = background concentration: assume zero for all toxicants except NH3* (µg/L or mg/L) Qw = permitted effluent flow (cfs, match s7Q10) s7Q10 = summer low flow used to protect aquatic life from chronic toxicity and human health through the consumption of water, fish, and shellfish from noncarcinogens (cfs) * Discussions are on-going with EPA on how best to address background concentrations Flows other than s7Q10 may be incorporated as applicable: 1Q10 = used in the equation to protect aquatic life from acute toxicity EPA default partition coefficients or the “Fraction Dissolved” converts the value for dissolved metal at laboratory conditions to total recoverable metal at in-stream ambient conditions. This factor is calculated using the linear partition coefficients found in The Metals Translator: Guidance for Calculating a Total Recoverable Permit Limit from a Dissolved Criterion (EPA 823-B-96-007, June 1996) and the equation: _Cdiss__ = _______1_______________ Ctotal 1 + { [Kpo] [ss(1+a)] [10-6] } Where: ss = in-stream suspended solids concentration [mg/l], minimum of 10 mg/L used, and Kpo and a = constants that express the equilibrium relationship between dissolved and adsorbed forms of metals. A list of constants used for each hardness-dependent metal can also be found in the RPA program under a sheet labeled DPCs. Permit No. NC0021474 Page 4 of 4 QA = used in the equation to protect human health through the consumption of water, fish, and shellfish from carcinogens 30Q2 = used in the equation to protect aesthetic quality 6. The permit writer enters the most recent 2-3 years of effluent data for each pollutant of concern. Data entered must have been taken within four and one-half years prior to the date of the permit application (40 CFR 122.21). The RPA spreadsheet estimates the 95th percentile upper concentration of each pollutant. The Predicted Max concentrations are compared to the Total allowable concentrations to determine if a permit limit is necessary. If the predicted max exceeds the acute or chronic Total allowable concentrations, the discharge is considered to show reasonable potential to violate the water quality standard, and a permit limit (Total allowable concentration) is included in the permit in accordance with the U.S. EPA Technical Support Document for Water Quality-Based Toxics Control published in 1991. 7. When appropriate, permit writers develop facility specific compliance schedules in accordance with the EPA Headquarters Memo dated May 10, 2007 from James Hanlon to Alexis Strauss on 40 CFR 122.47 Compliance Schedule Requirements. 8. The Total Chromium NC WQS was removed and replaced with trivalent chromium and hexavalent chromium Water Quality Standards. As a cost savings measure, total chromium data results may be used as a conservative surrogate in cases where there are no analytical results based on chromium III or VI. In these cases, the projected maximum concentration (95th %) for total chromium will be compared against water quality standards for chromium III and chromium VI. 9. Effluent hardness sampling and instream hardness sampling, upstream of the discharge, are inserted into all permits with facilities monitoring for hardness-dependent metals to ensure the accuracy of the permit limits and to build a more robust hardness dataset. 10. Hardness and flow values used in the Reasonable Potential Analysis for this permit included: Parameter Value Comments (Data Source) Average Effluent Hardness (mg/L) [Total as, CaCO3 or (Ca+Mg)] 71.2 Average from April 2018 to September 2022 samples Average Upstream Hardness (mg/L) [Total as, CaCO3 or (Ca+Mg)] 25 Default used 7Q10 summer (cfs) 0 Previous Fact Sheet; historical file 1Q10 (cfs) 0 Calculated in RPA Permitted Flow (MGD) 2.5, with expansions at 4.0 and 6.0 NPDES Files; 2022 Modification Request Date: _____11/23/2022________________________ Permit Writer: ______Nick Coco________________ NH3/TRC WLA Calculations Facility: Mebane WWTP PermitNo. NC0021474 Prepared By: Nick Coco Enter Design Flow (MGD):2.5 Enter s7Q10 (cfs):0 Enter w7Q10 (cfs):0 Total Residual Chlorine (TRC)Ammonia (Summer) Daily Maximum Limit (ug/l)Monthly Average Limit (mg NH3-N/l) s7Q10 (CFS)0 s7Q10 (CFS)0 DESIGN FLOW (MGD)2.5 DESIGN FLOW (MGD)2.5 DESIGN FLOW (CFS)3.875 DESIGN FLOW (CFS)3.875 STREAM STD (UG/L)17.0 STREAM STD (MG/L)1.0 Upstream Bkgd (ug/l)0 Upstream Bkgd (mg/l)0.22 IWC (%)100.00 IWC (%)100.00 Allowable Conc. (ug/l)17 Allowable Conc. (mg/l)1.0 Consistent with current permit limit. Maintain limit.More stringent than current permit limit. Apply limit. Ammonia (Winter) Monthly Average Limit (mg NH3-N/l) Fecal Coliform w7Q10 (CFS)0 Monthly Average Limit:200/100ml DESIGN FLOW (MGD)2.5 (If DF >331; Monitor)DESIGN FLOW (CFS)3.875 (If DF<331; Limit)STREAM STD (MG/L)1.8 Dilution Factor (DF)1.00 Upstream Bkgd (mg/l)0.22 IWC (%)100.00 Allowable Conc. (mg/l)1.8 More stringent than current permit limit. Apply limit. Total Residual Chlorine 1. Cap Daily Max limit at 28 ug/l to protect for acute toxicity Ammonia (as NH3-N) 1. If Allowable Conc > 35 mg/l, Monitor Only 2. Monthly Avg limit x 3 = Weekly Avg limit (Municipals) 3. Monthly Avg limit x 5 = Daily Max limit (Non-Munis) If the allowable ammonia concentration is > 35 mg/L, no limit shall be imposed Fecal Coliform 1. Monthly Avg limit x 2 = 400/100 ml = Weekly Avg limit (Municipals) = Daily Max limit (Non-Muni) 11/22/22 WQS = 12 ng/L V:2013-6 Facility Name /Permit No. : Total Mercury 1631E PQL = 0.5 ng/L 7Q10s = 0.000 cfs WQBEL = 12.00 ng/L Date Modifier Data Entry Value Permitted Flow = 2.500 47 ng/L 4/5/18 <1 0.5 7/19/18 1.06 1.06 10/12/18 4.46 4.46 11/29/18 6.21 6.21 12/13/18 3.99 3.99 3.2 ng/L - Annual Average for 2018 1/10/19 1.96 1.96 4/11/19 1.57 1.57 7/11/19 3.61 3.61 8/15/19 2.9 2.9 9/12/19 2.2 2.2 10/24/19 2.81 2.81 11/21/19 1.32 1.32 12/5/19 1.47 1.47 2.2 ng/L - Annual Average for 2019 1/16/20 1.55 1.55 2/27/20 1.91 1.91 3/19/20 1.4 1.4 4/16/20 1.85 1.85 5/15/20 1.36 1.36 6/11/20 4.82 4.82 7/23/20 3.56 3.56 8/20/20 2.69 2.69 9/10/20 4 4 10/29/20 4.04 4.04 11/17/20 <1 0.5 12/10/20 1.16 1.16 2.4 ng/L - Annual Average for 2020 1/14/21 1.94 1.94 4/8/21 1.63 1.63 Mebane WWTP/NC0021474 No Limit Required MERCURY WQBEL/TBEL EVALUATION MMP Required 7/15/21 10.2 10.2 4.6 ng/L - Annual Average for 2021 1/13/22 1.77 1.77 4/21/22 1.64 1.64 7/21/22 3.38 3.38 2.3 ng/L - Annual Average for 2022 Mebane WWTP/NC0021474 Mercury Data Statistics (Method 1631E) 2018 2019 2020 2021 2022 # of Samples 5 8 12 3 3 Annual Average, ng/L 3.2 2.2 2.4 4.59 2.263333 Maximum Value, ng/L 6.21 3.61 4.82 10.2 3.38 TBEL, ng/L WQBEL, ng/L 12.0 47 MRs Between and Violation Category:Program Category: Param Name County:Subbasin:%Violation Action: Major Minor:% Permit: Facility Name: Region:--NC0021474 %% % % Limit Violation % % 11 2017 11 2022 MONITORING REPORT(MR) VIOLATIONS for:11/10/22Report Date:1Page:of 4 PERMIT:NC0021474 FACILITY:City of Mebane - Mebane WWTP COUNTY:Alamance REGION:Winston-Salem % Over UNIT OF MEASURE VIOLATION ACTIONVIOLATION TYPECALCULATED VALUELIMITFREQUENCYVIOLATION DATEPARAMETERLOCATIONMONITORING REPORT Limit Violation OUTFALL 08 - 2018 001 Effluent BOD, 5-Day (20 Deg. C) - Concentration 08/31/18 2 X week Monthly Average Exceeded Proceed to NOD5.165mg/l 3.1 09 - 2018 001 Effluent BOD, 5-Day (20 Deg. C) - Concentration 09/22/18 2 X week Weekly Average Exceeded No Action, BPJ7.97.5mg/l 5.3 09 - 2018 001 Effluent BOD, 5-Day (20 Deg. C) - Concentration 09/30/18 2 X week Monthly Average Exceeded No Action, BPJ5.235mg/l 4.7 04 - 2019 001 Effluent BOD, 5-Day (20 Deg. C) - Concentration 04/13/19 2 X week Weekly Average Exceeded Proceed to NOD8.957.5mg/l 19.3 08 - 2022 001 Effluent BOD, 5-Day (20 Deg. C) - Concentration 08/13/22 2 X week Weekly Average Exceeded None253.27.5mg/l 3,276 08 - 2022 001 Effluent BOD, 5-Day (20 Deg. C) - Concentration 08/31/22 2 X week Monthly Average Exceeded None77.895mg/l 1,457.8 01 - 2018 001 Effluent Chlorine, Total Residual 01/09/18 5 X week Daily Maximum Exceeded No Action, BPJ4417ug/l 158.8 01 - 2018 001 Effluent Chlorine, Total Residual 01/29/18 5 X week Daily Maximum Exceeded No Action, BPJ4817ug/l 182.4 01 - 2018 001 Effluent Chlorine, Total Residual 01/30/18 5 X week Daily Maximum Exceeded No Action, BPJ3017ug/l 76.5 03 - 2018 001 Effluent Chlorine, Total Residual 03/13/18 5 X week Daily Maximum Exceeded No Action, BPJ4317ug/l 152.9 04 - 2018 001 Effluent Chlorine, Total Residual 04/11/18 5 X week Daily Maximum Exceeded No Action, BPJ3317ug/l 94.1 08 - 2018 001 Effluent Chlorine, Total Residual 08/13/18 5 X week Daily Maximum Exceeded No Action, BPJ4617ug/l 170.6 08 - 2018 001 Effluent Chlorine, Total Residual 08/23/18 5 X week Daily Maximum Exceeded No Action, BPJ3417ug/l 100 08 - 2018 001 Effluent Chlorine, Total Residual 08/29/18 5 X week Daily Maximum Exceeded No Action, BPJ2917ug/l 70.6 09 - 2018 001 Effluent Chlorine, Total Residual 09/06/18 5 X week Daily Maximum Exceeded No Action, BPJ4717ug/l 176.5 09 - 2018 001 Effluent Chlorine, Total Residual 09/20/18 5 X week Daily Maximum Exceeded No Action, BPJ4517ug/l 164.7 MRs Between and Violation Category:Program Category: Param Name County:Subbasin:%Violation Action: Major Minor:% Permit: Facility Name: Region:--NC0021474 %% % % Limit Violation % % 11 2017 11 2022 MONITORING REPORT(MR) VIOLATIONS for:11/10/22Report Date:2Page:of 4 PERMIT:NC0021474 FACILITY:City of Mebane - Mebane WWTP COUNTY:Alamance REGION:Winston-Salem % Over UNIT OF MEASURE VIOLATION ACTIONVIOLATION TYPECALCULATED VALUELIMITFREQUENCYVIOLATION DATEPARAMETERLOCATIONMONITORING REPORT Limit Violation OUTFALL 10 - 2018 001 Effluent Chlorine, Total Residual 10/04/18 5 X week Daily Maximum Exceeded No Action, BPJ3317ug/l 94.1 10 - 2018 001 Effluent Chlorine, Total Residual 10/05/18 5 X week Daily Maximum Exceeded No Action, BPJ4817ug/l 182.4 10 - 2018 001 Effluent Chlorine, Total Residual 10/22/18 5 X week Daily Maximum Exceeded No Action, BPJ4117ug/l 141.2 11 - 2018 001 Effluent Chlorine, Total Residual 11/13/18 5 X week Daily Maximum Exceeded No Action, BPJ4617ug/l 170.6 11 - 2018 001 Effluent Chlorine, Total Residual 11/16/18 5 X week Daily Maximum Exceeded No Action, BPJ2817ug/l 64.7 01 - 2019 001 Effluent Chlorine, Total Residual 01/23/19 5 X week Daily Maximum Exceeded No Action, BPJ4717ug/l 176.5 02 - 2019 001 Effluent Chlorine, Total Residual 02/19/19 5 X week Daily Maximum Exceeded No Action, BPJ4417ug/l 158.8 04 - 2019 001 Effluent Chlorine, Total Residual 04/30/19 5 X week Daily Maximum Exceeded No Action, BPJ4617ug/l 170.6 06 - 2019 001 Effluent Chlorine, Total Residual 06/17/19 5 X week Daily Maximum Exceeded No Action, BPJ3717ug/l 117.6 07 - 2019 001 Effluent Chlorine, Total Residual 07/03/19 5 X week Daily Maximum Exceeded No Action, BPJ3017ug/l 76.5 07 - 2019 001 Effluent Chlorine, Total Residual 07/29/19 5 X week Daily Maximum Exceeded No Action, BPJ4617ug/l 170.6 08 - 2019 001 Effluent Chlorine, Total Residual 08/06/19 5 X week Daily Maximum Exceeded No Action, BPJ3017ug/l 76.5 09 - 2019 001 Effluent Chlorine, Total Residual 09/23/19 5 X week Daily Maximum Exceeded No Action, BPJ4617ug/l 170.6 10 - 2019 001 Effluent Chlorine, Total Residual 10/25/19 5 X week Daily Maximum Exceeded No Action, BPJ1817ug/l 5.9 12 - 2019 001 Effluent Chlorine, Total Residual 12/23/19 5 X week Daily Maximum Exceeded No Action, BPJ4017ug/l 135.3 01 - 2020 001 Effluent Chlorine, Total Residual 01/14/20 5 X week Daily Maximum Exceeded No Action, BPJ3617ug/l 111.8 MRs Between and Violation Category:Program Category: Param Name County:Subbasin:%Violation Action: Major Minor:% Permit: Facility Name: Region:--NC0021474 %% % % Limit Violation % % 11 2017 11 2022 MONITORING REPORT(MR) VIOLATIONS for:11/10/22Report Date:3Page:of 4 PERMIT:NC0021474 FACILITY:City of Mebane - Mebane WWTP COUNTY:Alamance REGION:Winston-Salem % Over UNIT OF MEASURE VIOLATION ACTIONVIOLATION TYPECALCULATED VALUELIMITFREQUENCYVIOLATION DATEPARAMETERLOCATIONMONITORING REPORT Limit Violation OUTFALL 01 - 2020 001 Effluent Chlorine, Total Residual 01/24/20 5 X week Daily Maximum Exceeded No Action, BPJ4417ug/l 158.8 03 - 2020 001 Effluent Chlorine, Total Residual 03/10/20 5 X week Daily Maximum Exceeded No Action, BPJ3917ug/l 129.4 03 - 2020 001 Effluent Chlorine, Total Residual 03/19/20 5 X week Daily Maximum Exceeded No Action, BPJ3617ug/l 111.8 05 - 2020 001 Effluent Chlorine, Total Residual 05/11/20 5 X week Daily Maximum Exceeded No Action, BPJ4317ug/l 152.9 06 - 2020 001 Effluent Chlorine, Total Residual 06/02/20 5 X week Daily Maximum Exceeded No Action, BPJ2417ug/l 41.2 11 - 2020 001 Effluent Chlorine, Total Residual 11/30/20 5 X week Daily Maximum Exceeded No Action, BPJ3717ug/l 117.6 12 - 2020 001 Effluent Chlorine, Total Residual 12/17/20 5 X week Daily Maximum Exceeded No Action, BPJ2017ug/l 17.6 03 - 2022 001 Effluent Chlorine, Total Residual 03/17/22 5 X week Daily Maximum Exceeded No Action, BPJ2117ug/l 23.5 03 - 2022 001 Effluent Chlorine, Total Residual 03/23/22 5 X week Daily Maximum Exceeded No Action, BPJ3917ug/l 129.4 08 - 2022 001 Effluent Chlorine, Total Residual 08/22/22 5 X week Daily Maximum Exceeded No Action, BPJ3217ug/l 88.2 08 - 2022 001 Effluent Chlorine, Total Residual 08/25/22 5 X week Daily Maximum Exceeded No Action, BPJ4717ug/l 176.5 02 - 2021 001 Effluent Flow, in conduit or thru treatment plant 02/28/21 Continuous Monthly Average Exceeded No Action, BPJ2.752.5mgd 10.0 11 - 2018 001 Effluent Nitrogen, Ammonia Total (as N) - Concentration 11/30/18 2 X week Monthly Average Exceeded Proceed to NOV5.494mg/l 37.3 12 - 2018 001 Effluent Nitrogen, Ammonia Total (as N) - Concentration 12/01/18 2 X week Weekly Average Exceeded Proceed to NOV13.5512mg/l 12.9 12 - 2018 001 Effluent Nitrogen, Ammonia Total (as N) - Concentration 12/15/18 2 X week Weekly Average Exceeded Proceed to NOV12.3712mg/l 3.1 12 - 2018 001 Effluent Nitrogen, Ammonia Total (as N) - Concentration 12/29/18 2 X week Weekly Average Exceeded Proceed to NOV12.6512mg/l 5.4 MRs Between and Violation Category:Program Category: Param Name County:Subbasin:%Violation Action: Major Minor:% Permit: Facility Name: Region:--NC0021474 %% % % Limit Violation % % 11 2017 11 2022 MONITORING REPORT(MR) VIOLATIONS for:11/10/22Report Date:4Page:of 4 PERMIT:NC0021474 FACILITY:City of Mebane - Mebane WWTP COUNTY:Alamance REGION:Winston-Salem % Over UNIT OF MEASURE VIOLATION ACTIONVIOLATION TYPECALCULATED VALUELIMITFREQUENCYVIOLATION DATEPARAMETERLOCATIONMONITORING REPORT Limit Violation OUTFALL 12 - 2018 001 Effluent Nitrogen, Ammonia Total (as N) - Concentration 12/31/18 2 X week Monthly Average Exceeded Proceed to NOV10.944mg/l 173.4 02 - 2020 001 Effluent Oxygen, Dissolved (DO)02/06/20 5 X week Daily Minimum Not Reached Proceed to NOD5.86mg/l 3.3 11 - 2020 001 Effluent Oxygen, Dissolved (DO)11/12/20 5 X week Daily Minimum Not Reached Proceed to NOD4.16mg/l 31.7 EPA United States Environmental Protection Agency Washington, D.C. 20460 Water Compliance Inspection Report Form Approved. OMB No. 2040-0057 Approval expires 8-31-98 Section A: National Data System Coding (i.e., PCS) Transaction Code NPDES yr/mo/day Inspection Type Inspector Fac Type 1 N 52 NC0021474 21/08/19 P S31112171819 20 21 66 Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA ----------------------Reserved------------------- 5 N67707172 73 74 75 80 Section B: Facility Data Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include POTW name and NPDES permit Number) Mebane WWTP 635 Corregidor Rd Mebane NC 27302 Entry Time/Date Permit Effective Date Exit Time/Date Permit Expiration Date 10:00AM 21/08/19 14/07/01 Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s) /// Amy H Varinoski/ORC/919-304-9217/ Other Facility Data 01:00PM 21/08/19 19/05/31 Name, Address of Responsible Official/Title/Phone and Fax Number Linda R Holt,106 E Washington St Mebane NC 27302//919-563-6141/Contacted No Section C: Areas Evaluated During Inspection (Check only those areas evaluated) Permit Records/Reports Compliance Schedules Pretreatment Laboratory Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) (See attachment summary) Name(s) and Signature(s) of Inspector(s)Agency/Office/Phone and Fax Numbers Date Jim J Gonsiewski DWR/Division of Water Quality/336-776-9704/ Patricia Lowery DWR/WSRO WQ/336-776-9691/ Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete. Page#1 NPDES yr/mo/day 21/08/19 Inspection Type P3111218 1 Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) On August 19. 2021 a Pretreatment Compliance Inspection (PCI) was performed by Tricia Lowery and Jim Gonsiewski of the Winston-Salem Regional Office. Ms. Amy Varinoski was present for the inspection. The purpose of this inspection was to determine the effectiveness of the Town's pretreatment program, which includes reviewing the files, POTW plant performance, industry monitoring data, and adherence to the enforcement response plan (ERP). This is a 2.5 MGD permitted facility. The City has five (5) Significant Industrial Users (SIUs), three (3) of which are categorical. The publicly owned treatment works (POTW) had a limit violation of DO in November 2020 and a flow limit violation in February 2021. Both of these violations were due to a heavy rain event. There are no plant problems related to pretreatment issues and, other than the DO and flow limit violations previously stated. Ms. Varinoski stated changes were coming to the pretreatment program (and POTW it serves) in the future that will include dropping 3 SIU’s from the program. These three SIU’s: Liggett, Synergy and Sandvit, will be directed to the City of Graham POTW. Ms. Varinoski will inform the DEQ-DWR of the specific dates when these SIU’s will be diverted to Graham. The facility is very well operated. The Headworks Analysis (HWA) renewal was submitted on March 26, 2021. The HWA is currently being reviewed for approval. The last Industrial Waste Survey (IWS) was submitted on November 23, 2020. The IWS was approved on January 13, 2021. The next IWS is due on January 10, 2026. The Sewer Use Ordinance (SUO) was approved on December 10, 2012. The Enforcement Response Plan (ERP) was submitted on February 5, 2021 and approved on February 13, 2020. The Long-Term Monitoring Plan (LTMP) was submitted on June 20, 2019 and approved on July 18, 2019. The Long-Term Monitoring Plan (LTMP) is being conducted at the proper locations and frequencies. Industrial User Permit (IUP) File Review A review of the file for PPG Coating Services (#0133) revealed that the monitoring data was well organized and compliant. A review of the file for Sandvit. (#0118) revealed that the monitoring data was well organized and compliant. A review of the file for Liggett (#0132) revealed that the monitoring data was well organized and compliant. The slug control plan for PPG Coating Services (#0133) was in good order. The slug control plan for Sandvit. (#0118) was in good order. The slug control plan for Liggett (#0132) was in good order. Upcoming changes: Liggett, Synergy and Sandvit will be directed to the City of Graham POTW. Ms. Varinoski will inform the DEQ-DWR of the specific dates when these SIU’s will be diverted to Graham. NC0021474 17 (Cont.) Page#2 Permit:NC0021474 Inspection Date:08/19/2021 Owner - Facility: Inspection Type: Mebane WWTP Pretreatment Compliance The pretreatment program is considered satisfactory. Ms. Varinoski runs an excellent pretreatment program. Page#3 Permit:NC0021474 Inspection Date:08/19/2021 Owner - Facility: Inspection Type: Mebane WWTP Pretreatment Compliance Permit Yes No NA NE (If the present permit expires in 6 months or less). Has the permittee submitted a new application? Is the facility as described in the permit? # Are there any special conditions for the permit? Is access to the plant site restricted to the general public? Is the inspector granted access to all areas for inspection? noneComment: Compliance Schedules Yes No NA NE Is there a compliance schedule for this facility? Is the facility compliant with the permit and conditions for the review period? noneComment: Page#4 EPA United States Environmental Protection Agency Washington, D.C. 20460 Water Compliance Inspection Report Form Approved. OMB No. 2040-0057 Approval expires 8-31-98 Section A: National Data System Coding (i.e., PCS) Transaction Code NPDES yr/mo/day Inspection Type Inspector Fac Type 1 N 52 NC0021474 22/06/24 C S31112171819 20 21 66 Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA ----------------------Reserved------------------- N67707172 73 74 75 80 Section B: Facility Data Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include POTW name and NPDES permit Number) Mebane WWTP 635 Corregidor Rd Mebane NC 27302 Entry Time/Date Permit Effective Date Exit Time/Date Permit Expiration Date 10:00AM 22/06/24 14/07/01 Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s) /// Amanda Catharine Hill/ORC/919-563-6141/ Antony Jerome Bowes/ORC/919-304-9216/ Dennis James Hodge/ORC/336-906-5583/ Other Facility Data 12:00PM 22/06/24 19/05/31 Name, Address of Responsible Official/Title/Phone and Fax Number Linda R Holt,106 E Washington St Mebane NC 27302//919-563-6141/Contacted No Section C: Areas Evaluated During Inspection (Check only those areas evaluated) Permit Flow Measurement Operations & Maintenance Records/Reports Self-Monitoring Program Sludge Handling Disposal Facility Site Review Effluent/Receiving Waters Laboratory Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) (See attachment summary) Name(s) and Signature(s) of Inspector(s)Agency/Office/Phone and Fax Numbers Date Ron Boone DWR/WSRO WQ/336-776-9690/ Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete. Page#1 NPDES yr/mo/day 22/06/24 Inspection Type C3111218 1 Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) Ron Boone, of the Winston-Salem Regional Office of the NC Division of Water Resources, conducted a compliance evaluation inspection of the Mebane WWTP on 6/24/22. The assistance and cooperation of Dennis Hodge, Tony Bowes, and Amanda Hill was greatly appreciated. Inspection findings are detailed below and in the accompanying checklist. Records Review: Operational records were reviewed and found to be complete, current, and compliant. This includes operator visitation logs, operations logs, maintenance logs, and other pertinent records that the operators provided during the inspection. Records are kept for at least 3 years. Analytical records are complete, current, and compliant. The permittee uses Meritech labs for BOD, nitrogen, metals, oil & grease, and cyanide. Field parameters are completed in house. Chains of custody, lab reports, etc, were all available for review. All analytical records are kept for at least 5 years. No discrepancies in reporting lab results were noted. The current permit is maintained onsite. Plant Inspection: The bar screen is operational and in good condition. The aeration basins (AB) appear to be in good condition and the mixed liquor appears healthy. The basins used floating aerators and not all run at the same time, which creates oxic and anoxic zones to aid in nutrient management. The clarifiers also appear in good condition and operating properly. The weirs appear to be level and no short circuiting was noticed in the clarifiers. The plant uses liquid sodium hypochlorite for disinfection and liquid sodium bisulfite for dechlorination. Backups for all pumps are kept on hand. The effluent flow meter is used for reporting and it was last calibrated in June of 2022. It reports both a constant flow rate as well as the total flow. The meter is calibrated quarterly so it is due again in September 2022. The plant's generators supply power for the whole facility. The effluent appeared excellent. It was very clear and there is no odor. Fish were seen in the immediate area of the outfall. The inspector has the following recommendations: Keep up the good work! No permit deficiencies or violations were noted during the inspection. NC0021474 17 (Cont.) Page#2 Permit:NC0021474 Inspection Date:06/24/2022 Owner - Facility: Inspection Type: Mebane WWTP Compliance Evaluation Permit Yes No NA NE (If the present permit expires in 6 months or less). Has the permittee submitted a new application? Is the facility as described in the permit? # Are there any special conditions for the permit? Is access to the plant site restricted to the general public? Is the inspector granted access to all areas for inspection? NoneComment: Record Keeping Yes No NA NE Are records kept and maintained as required by the permit? Is all required information readily available, complete and current? Are all records maintained for 3 years (lab. reg. required 5 years)? Are analytical results consistent with data reported on DMRs? Is the chain-of-custody complete? Dates, times and location of sampling Name of individual performing the sampling Results of analysis and calibration Dates of analysis Name of person performing analyses Transported COCs Are DMRs complete: do they include all permit parameters? Has the facility submitted its annual compliance report to users and DWQ? (If the facility is = or > 5 MGD permitted flow) Do they operate 24/7 with a certified operator on each shift? Is the ORC visitation log available and current? Is the ORC certified at grade equal to or higher than the facility classification? Is the backup operator certified at one grade less or greater than the facility classification? Is a copy of the current NPDES permit available on site? Facility has copy of previous year's Annual Report on file for review? NoneComment: Laboratory Yes No NA NE Are field parameters performed by certified personnel or laboratory? Page#3 Permit:NC0021474 Inspection Date:06/24/2022 Owner - Facility: Inspection Type: Mebane WWTP Compliance Evaluation Laboratory Yes No NA NE Are all other parameters(excluding field parameters) performed by a certified lab? # Is the facility using a contract lab? # Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees Celsius)? Incubator (Fecal Coliform) set to 44.5 degrees Celsius+/- 0.2 degrees? Incubator (BOD) set to 20.0 degrees Celsius +/- 1.0 degrees? NoneComment: Influent Sampling Yes No NA NE # Is composite sampling flow proportional? Is sample collected above side streams? Is proper volume collected? Is the tubing clean? # Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees Celsius)? Is sampling performed according to the permit? NoneComment: Effluent Sampling Yes No NA NE Is composite sampling flow proportional? Is sample collected below all treatment units? Is proper volume collected? Is the tubing clean? # Is proper temperature set for sample storage (kept at less than or equal to 6.0 degrees Celsius)? Is the facility sampling performed as required by the permit (frequency, sampling type representative)? NoneComment: Upstream / Downstream Sampling Yes No NA NE Is the facility sampling performed as required by the permit (frequency, sampling type, and sampling location)? Not required due to participation in the river basin association.Comment: Page#4 Permit:NC0021474 Inspection Date:06/24/2022 Owner - Facility: Inspection Type: Mebane WWTP Compliance Evaluation Bar Screens Yes No NA NE Type of bar screen a.Manual b.Mechanical Are the bars adequately screening debris? Is the screen free of excessive debris? Is disposal of screening in compliance? Is the unit in good condition? NoneComment: Grit Removal Yes No NA NE Type of grit removal a.Manual b.Mechanical Is the grit free of excessive organic matter? Is the grit free of excessive odor? # Is disposal of grit in compliance? NoneComment: Aeration Basins Yes No NA NE Mode of operation Ext. Air Type of aeration system Surface Is the basin free of dead spots? Are surface aerators and mixers operational? Are the diffusers operational? Is the foam the proper color for the treatment process? Does the foam cover less than 25% of the basin’s surface? Is the DO level acceptable? Is the DO level acceptable?(1.0 to 3.0 mg/l) Surface aerators are alternated and not all are in operation at all times to create oxic and anoxic zones. Comment: Secondary Clarifier Yes No NA NE Is the clarifier free of black and odorous wastewater? Is the site free of excessive buildup of solids in center well of circular clarifier? Page#5 Permit:NC0021474 Inspection Date:06/24/2022 Owner - Facility: Inspection Type: Mebane WWTP Compliance Evaluation Secondary Clarifier Yes No NA NE Are weirs level? Is the site free of weir blockage? Is the site free of evidence of short-circuiting? Is scum removal adequate? Is the site free of excessive floating sludge? Is the drive unit operational? Is the return rate acceptable (low turbulence)? Is the overflow clear of excessive solids/pin floc? Is the sludge blanket level acceptable? (Approximately ¼ of the sidewall depth) NoneComment: Pumps-RAS-WAS Yes No NA NE Are pumps in place? Are pumps operational? Are there adequate spare parts and supplies on site? NoneComment: Filtration (High Rate Tertiary)Yes No NA NE Type of operation: Is the filter media present? Is the filter surface free of clogging? Is the filter free of growth? Is the air scour operational? Is the scouring acceptable? Is the clear well free of excessive solids and filter media? Comment: Flow Measurement - Effluent Yes No NA NE # Is flow meter used for reporting? Is flow meter calibrated annually? Is the flow meter operational? (If units are separated) Does the chart recorder match the flow meter? Page#6 Permit:NC0021474 Inspection Date:06/24/2022 Owner - Facility: Inspection Type: Mebane WWTP Compliance Evaluation Flow Measurement - Effluent Yes No NA NE Meter is calibrated quarterly. Last calibrated in June 2022.Comment: Disinfection-Liquid Yes No NA NE Is there adequate reserve supply of disinfectant? (Sodium Hypochlorite) Is pump feed system operational? Is bulk storage tank containment area adequate? (free of leaks/open drains) Is the level of chlorine residual acceptable? Is the contact chamber free of growth, or sludge buildup? Is there chlorine residual prior to de-chlorination? Sodium hypochloriteComment: De-chlorination Yes No NA NE Type of system ?Liquid Is the feed ratio proportional to chlorine amount (1 to 1)? Is storage appropriate for cylinders? # Is de-chlorination substance stored away from chlorine containers? Are the tablets the proper size and type? Sodium BisulfiteComment: Are tablet de-chlorinators operational? Number of tubes in use? NoneComment: Pump Station - Effluent Yes No NA NE Is the pump wet well free of bypass lines or structures? Are all pumps present? Are all pumps operable? Are float controls operable? Is SCADA telemetry available and operational? Is audible and visual alarm available and operational? NoneComment: Effluent Pipe Yes No NA NE Is right of way to the outfall properly maintained? Page#7 Permit:NC0021474 Inspection Date:06/24/2022 Owner - Facility: Inspection Type: Mebane WWTP Compliance Evaluation Effluent Pipe Yes No NA NE Are the receiving water free of foam other than trace amounts and other debris? If effluent (diffuser pipes are required) are they operating properly? NoneComment: Aerobic Digester Yes No NA NE Is the capacity adequate? Is the mixing adequate? Is the site free of excessive foaming in the tank? # Is the odor acceptable? # Is tankage available for properly waste sludge? NoneComment: Operations & Maintenance Yes No NA NE Is the plant generally clean with acceptable housekeeping? Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable Solids, pH, DO, Sludge Judge, and other that are applicable? NoneComment: Standby Power Yes No NA NE Is automatically activated standby power available? Is the generator tested by interrupting primary power source? Is the generator tested under load? Was generator tested & operational during the inspection? Do the generator(s) have adequate capacity to operate the entire wastewater site? Is there an emergency agreement with a fuel vendor for extended run on back-up power? Is the generator fuel level monitored? NoneComment: Page#8 Whole Effluent Toxicity Testing and Self Monitoring Summary Mebane WWTPNC0021474/001chr lim: 90%Ceri7dPFBegin:7/1/2014Freq:QJan Apr Jul OctNonComp:SingleCounty:AlamanceRegion:WSROBasin:CPF027Q10:0.0IWC:100SOC_JOC:PF:2.5JFMAMJJASOND2018 Pass >100(P)‐‐Pass >100(P)‐‐Pass >100(P)‐‐Fail82.2 >1002019 Pass‐‐Pass‐‐Fail>100>100<22.5>100(s) >100(s)2020 Pass(s)‐‐Pass‐‐Pass‐‐Pass‐‐2021 Pass‐‐Pass‐‐Pass‐‐Pass‐‐2022 Pass‐‐Pass‐‐Fail>100>100‐‐‐Millpond WTP ‐ BayboroNC0088340/001Ac P/F Monit: 90% MMysd24PFBegin:11/1/2018Freq:QMar Jun Sep DecNonComp:County:PamlicoRegion:WAROBasin:NEU137Q10:NAIWC:NASOC_JOC:PF:JFMAMJJASOND2018‐‐Pass‐‐Pass‐‐HPass‐Pass2019‐‐Pass‐‐Pass‐‐Pass‐‐Pass2020‐‐Pass‐‐Pass‐‐Pass‐‐Pass2021‐‐Pass‐‐Fail‐‐Pass‐‐Pass2022‐‐Fail‐‐Fail‐‐‐‐‐‐Mills River WTP (NCG590034)NC0085511/001ANNUAL (NCG50003Fthd24PFBegin:4/1/2016Freq:AMar Jun Sep DecNonComp:County:HendersonRegion:AROBasin:FRB027Q10:IWC:SOC_JOC:PF:JFMAMJJASOND2018‐Pass‐‐Pass‐‐Pass‐‐Pass‐2019‐Pass‐‐Pass‐‐Pass‐‐Fail Pass‐2020‐Pass‐‐Pass‐‐Pass‐‐Pass‐2021‐‐‐Pass‐‐‐‐‐‐‐‐2022‐‐‐‐‐‐Pass‐‐‐‐‐M'Kean Maffitt (Southside) WWTPNC0023973/001Cerio7dPF lim: 3% @Ceri7dPFBegin:3/1/2018Freq:QMar Jun Sep DecNonComp:SingleCounty:New HanoverRegion:WIROBasin:CPF177Q10:TidalIWC:NASOC_JOC:PF:12.0JFMAMJJASOND2018‐‐Pass‐‐Pass‐‐HPass‐>100(P) Pass2019‐‐>12(P) Pass‐‐Pass‐‐Pass‐‐Pass2020‐‐>12(P) Pass‐‐Pass‐‐Pass‐‐Pass2021‐‐Pass >12(P)‐‐Pass‐‐Pass‐‐Pass2022‐‐Pass‐‐Pass‐‐>12 Pass‐‐‐Mocksville WTP (Hugh Lagle WTP)NC0089290/001Chr Cerio PF Monit: 9Ceri7dPFBegin:12/1/2013Freq:QMar Jun Sep DecNonComp:County:DavieRegion:WSROBasin:YAD067Q10:IWC:SOC_JOC:PF:JFMAMJJASOND2018‐‐Pass‐‐Pass‐‐Pass‐‐Pass2019‐‐Pass‐‐Pass‐‐Fail‐‐Pass2020‐‐Pass‐‐Pass‐‐Pass‐‐Fail2021‐‐Fail‐‐Pass‐‐Fail‐‐Fail2022‐‐Pass‐‐Pass‐‐Fail‐‐‐Page 72 of 118Legend:  P= Fathead minnow (Pimphales promelas), H=No Flow (facility is active), s = Split test between Certified Labs 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 A B C D E F G H I J K L M N O P Permittee-Facility Name NPDES Permit Number WWTP expansion 4.0 MGD & 6.0 MGD Stream reclass./adjustment Outfall relocation/adjustment Moadams Creek 0.8 WS-V; NSW 0 4/1/2018 to 9/1/2022 36.08743 N 79.28844 W 2.5 Designed Flow, mgd 2.5 # IUs # SIUs # CIUs # NSCIUs # IUs w/Local Permits or Other Types #IU Activity 1 433 2 403 3 433 4 403 5 433 6 7 1) facility has no SIU's, does have Division approved Pretreatment Program that is INACTIVE 2) facility has no SIU's, does not have Division approved Pretreatment Program 3) facility has SIUs and DWQ approved Pretreatment Program 3a) Full Program with LTMP 3b) Modified Program with STMP 4) additional conditions regarding Pretreatment attached or listed below 5) facility's sludge is being land applied or composted 6) facility's sludge is incinerated (add Beryllium and Mercury sampling according to § 503.43) 7) facility's sludge is taken to a landfill, if yes which landfill: 8) other % Removal Rate PQL from L/STMP, ug/l Required PQL per NPDES permit Recomm. PQL, ug/l Flow BOD TSS NH3 Arsenic 2.0 Barium Beryllium(5) Cadmium(1)0.5 Chromium(1)5.0 Copper(1)2.0 Cyanide Lead(1)2.0 Mercury(5)0.001 Molybdenum 10.0 Nickel(1) Selenium 1.0 Silver 1.0 Zinc(1)10.0 Sludge Flow to Disposal % Solids to Disposal Oil & Grease TN TP PFAS 1633 1,4 Dioxane COD Footnotes: (1) Always in the LTMP/STMP due to EPA-PT requirement (2) Only in LTMP/STMP if listed in sludge permit (3) Only in LTMP/STMP while SIU still discharges to POTW (4) Only in LTMP/STMP when pollutant is of concern to POTW (5) In LTMP/STMP, if sewage sludge is incinerated Please use blue font for the info updated by pw Please use red font for POC that need to be added/modified in L/STMP sampling plan Please use orange font and strikethrough for POC that may be removed from L/STMP POC list/sampling plan Blue shaded cell (D60:H81):Parameters usually included under that POC list Novo Health Services flow, pH, COD, O&G, TP, chromium, copper, lead, nickel, zinc, mercury, fluoride 7/1/2021 Sandvik Machining Solutions US LLC flow, pH, flupride, cadmium, chromium, copper, lead, nickel, zinc, mercury, selenium, silver, cyanide, TTO 7/1/2022 ORC's comments on IU/POC: POC submitted through Chemical Addendum or Supplemental Chemical Datasheet: Additional pollutants added to L/STMP due to POTWs concerns: NPDES pw's comments on IU/POC: Sludge Disposal Plan:Dewatered biosolids are transported by EMA Resources for use in production of compost by an additional third party. Status of Pretreatment Program (check all that apply) IUP Effective Date 1/1/2019Liggett Group, LLC IU Non Conventional Pollutans & Toxic Pollutant flow, pH, fluoride, TP, cadmium, chromium, copper, lead, nickel, zinc, mercury, cyanide, silver, TTO flow, pH, BOD, TSS, fluoride, TP, ammonia, zinc, mercury MetoKote PPG Coating Services flow, pH, cadmium, chromium, copper, lead, nickel, silver, zinc, cyanide, TTO, mercury, fluoride, TP 7/1/2019 Facility PT Staff, email Receiving Stream: Stream Class Oufall Lat. Receiving Stream: Stream Class Oufall Lat. NPDES Permit Writer2 5 Industrial User (IU) Name Comment: City of Mebane - Mebane WWTP NC0021474 New Industries Current Permitted Flow, mgd 5 3L/STMP approval date:7/18/2019 2. Industrial Users' Information. Pollutants of Concern (POC) Review Form c. POC review due to:8/9/2023 QA, cfs: 7Q10 (S), cfs: Nick Coco 1. Facility's General Information Date of (draft) Review NPDES Permit Writer (pw)HWA-AT/LTMP Review e. Contact Information Date of (final) Review Municipal NPDES renewal Regional Office (RO) Amy Varinoski, avarinoski@cityofmebane.com Version: 2022.09.28 RO PT Staff Facility discharges to WS waters Comments: 7/1/2022 d. IU Summary a. WWTP Capacity Summary Winston-Salem NPDES Permit Public Notice Date Other POC review trigger, explain: QA, cfs: 7Q10, cfs: Outfall Long. 0.163 b. PT Docs. Summary Permitted SIU Flow, mgd Jenny Graznak 3. Status of Pretreatment Program (check all that apply) Jenny Graznak RO NPDES Staff f. Receiving Stream 7Q10 update Industrial Connections & Solutions Chemical Addendum Submittal Date 10/27/2023 IWS approval date 1/13/2021 HWA-AT approval date Rec'd 3/26/2021 eDMR data evaluated from: NPDES Permit Effective Date Outfall II Outfall I Outfall Long. Is there a PWS intake downstream of the Facility's Outfall(s)? YES NO New NPDES POC Previous NPDES POC Required by EPA PT(1) POC due to Sludge (2) POC due to SIU (3) POTW POC (4) L/STMP Effluent Freq. PQLs review Comment POC in L/STMPParameter of Concern (POC) Check List NPDES Effluent Freq. Sludge Permit No: 4. LTMP/STMP and HWA Review PW: Find L/STMP document, HWA spreadsheet, DMR, previous and new NPDES permit for next section. 5. Comments Facility Summary/background information/NPDES-PT regulatory action: POC to be added/modified in L/STMP: Recommend addition of 1,4-dioxane based on NPDES requirements Page 1 POC Review Form (1) 1 Coco, Nick A From:Perlmutter, Gary Sent:Thursday, July 20, 2023 10:00 AM To:Coco, Nick A Subject:Fw: USGS response to DWR USGS Low Flows request # 2021-148 (dated 2021/08/26) for Haw River Alamance County...RE: [EXTERNAL] Low-flow request approval See fwd.  The 7Q10 is 58.1 cfs        Gary Perlmutter, MSc, Environmental Specialist II  NCDEQ / Division of Water Resources  NPDES Municipal Permitting Unit     919‐707‐3611  Office  919‐306‐1017  Cell  gary.perlmutter@deq.nc.gov    Physical Address: 512 N Salisbury St., Raleigh, NC 27604  Mailing Address: 1617 Mail Service Center, Raleigh, NC 27699‐1617     DEQ is updating its email addreses to @deq.nc.gov in phases from May 1st to June 9th. Employee email  addresses may look different, but email performance will not be impacted.     Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be  disclosed to third parties.     From: Weaver, John C <jcweaver@usgs.gov>  Sent: Tuesday, September 14, 2021 9:31 PM  To: Perlmutter, Gary <gary.perlmutter@ncdenr.gov>  Cc: Hill, David A <david.hill@ncdenr.gov>; Kebede, Adugna <adugna.kebede@ncdenr.gov>; Montebello, Michael J  <Michael.Montebello@ncdenr.gov>; Dowden, Doug <doug.dowden@ncdenr.gov>; Albertin, Klaus P  <klaus.albertin@ncdenr.gov>; Weaver, John C <jcweaver@usgs.gov>  Subject: USGS response to DWR USGS Low Flows request # 2021‐148 (dated 2021/08/26) for Haw River Alamance  County...RE: [EXTERNAL] Low‐flow request approval      CAUTION: External email. Do not click links or open attachments unless you verify. Send all suspicious email as an attachment to  Report Spam.       Gary,     Note: This is part 2 of 2 of a response to two low‐flow requests for the Haw River received from this requestor on the  same date.     2 In response to your inquiry about the low‐flow characteristics for a location on the Haw River near Eli Whitley  downstream from the mouth of Cane Creek in southeastern Alamance County and immediately upstream from the  confluence of the Alamance/Orange/Chatham County boundaries, the following information is provided:     A check of the low‐flow files here at the USGS South Atlantic Water Science Center (SAWSC, Raleigh office) indicates  low‐flow estimates previously determined for a location on the Haw River upstream from the point of interest, identified  by the lat/long coordinates (35.877771, ‐79.25006) associated with the email dated 08/26/2021 from the DWR USGS  Low Flow portal following your request submission.  Completed in May 1973, the low‐flow characteristics for Haw River  near Eli Whitney (station id 02096879, drainage area 1,083 sqmi, upstream from Cane Creek) were estimated based on  transfer of flow characteristics (by drainage‐area proration) from two nearby continuous‐record streamgages on the  Haw River in vicinity of the point of interest.     No USGS discharge records are known to exist for the point of interest.     In the absence of site‐specific discharge records sufficient for a low‐flow analysis, estimates of low‐flow characteristics at  ungaged locations would be determined by assessing a range in the low‐flow yields (expressed as flow per square  mile drainage area, or cfsm) at nearby sites where estimates have previously been determined.     A basin delineation completed using the online USGS StreamStats application for North Carolina  (https://streamstats.usgs.gov/ss/) indicates the drainage area for the point of interest (StreamStats adjusted  coordinates 35.87780, ‐79.24989 NAD83) is 1,150 sqmi, which confirms the drainage area submitted as part of the  request information.     For streams in Alamance County, low‐flow characteristics published by the USGS are provided in the following  reports:     (1) The first is a statewide report completed in the early 1990's.  It is USGS Water‐Supply Paper 2403, "Low‐flow  characteristics of streams in North Carolina" (Giese and Mason, 1993).  An online version of the report is available at  http://pubs.usgs.gov/wsp/2403/report.pdf.  The report provides the low‐flow characteristics (based on data through  1988) via regional relations and at‐site values for sites with drainage basins between 1 and 400 sqmi and not considered  or known to be affected by regulation and/or diversions.     (2) The second is a basin‐wide report for the Cape Fear River basin published in 2001.  It is USGS Water‐Resources  Investigations Report 01‐4094, "Low‐flow characteristics and discharge profiles for selected streams in the Cape Fear  River Basin, North Carolina, through 1998 " (Weaver and Pope, 2001).  An online version of the report is available  through http://nc.water.usgs.gov/reports/wri014094/.  The report provides the low‐flow characteristics (based on data  through 1998) for continuous‐record gaging stations and partial‐record sites within the Cape Fear River basin.  The  report also provides low‐flow discharge profiles (7Q10, 30Q2, winter 7Q10, and 7Q2) for the Cape Fear River and  selected tributaries within the basin.     (3) The third is a statewide report published in March 2015.  It is USGS Scientific Investigations Report 2015‐5001, "Low‐ flow characteristics and flow‐duration statistics for selected USGS continuous‐record streamgaging stations in North  Carolina through 2012" (Weaver, 2015).  The report is available online at http://pubs.usgs.gov/sir/2015/5001/.  The  report provides updated low‐flow characteristics and flow‐duration statistics for 266 active (as of 2012 water year) and  discontinued streamgages across the state where a minimum of 10 climatic years discharge records were available for  flow analyses.     Low‐flow characteristics estimated for point of interest:     For the record: Confidence levels in the low‐flow characteristics provided below are considered to be very low.  The  reach of the Haw River upstream and downstream from this point of interest is known or considered to be cumulatively  affected by effects of flow regulation from multiple impoundments located within several large sub‐basins, minor  3 regulation by small dams scattered along the river, and multiple flow diversions within the basin (including major  municipal diversions within the Buffalo Creek sub‐basins across Guilford County).     Below is a table showing the presence of two actively operated continuous‐record streamgages on the Haw River in  vicinity of the point of interest.  The upstream site is Haw River at Haw River in Alamance County (station id 02096500,  drainage area 606 sqmi) with period of record from the 1929 water year through current (September 2021).  The  downstream site is Haw River near Bynum in Chatham County (station id 02096960, drainage area 1,275 sqmi) with  period of record from the 1974 water year through current.     Using the published low‐flow characteristics (Weaver, 2015) at the Haw River and Bynum streamgages, the equivalent  low‐flow yields (cfsm) were determined for these two streamgages.  The unit low‐flow yields for the point of interest  were then pro‐rated on the basis of drainage area between the low‐flow yields at the Haw River and Bynum  streamgages.  The pro‐rated results for the winter 7Q10 discharge and annual 7Q2 discharge were not within the range  of the published low‐flow statistics for the two reference streamgages.  Therefore, it was judged that these statistics  cannot be provided at this time for the point of interest.     While pro‐rated results for the annual 7Q10 and 30Q2 discharges were within ranges of the published low‐flow statistics  for the two reference streamgages, the pattern of low‐flow yields between the two reference sites does not result in any  acceptable level of confidence in the computed values.  Future streamflow records need to be collected at or near this  point of interest to provide for a higher level of confidence in low‐flow characteristics along this reach of the Haw River.     For the purposes of completing this response, it was judged to “heavily round” both the estimated 7Q10 and 30Q2  discharges as indicated below.      Annual 7Q10 discharge = 55 cfs (rounded)  Annual 30Q2 discharge = 150 cfs (rounded)  Winter 7Q10 discharge = not determined  Annual 7Q10 discharge = not determined          USGS station  Drainage area  (sqmi)  7Q10  (cfs) 7Q10 (cfsm)  30Q2  (cfs)  30Q2  (cfsm)  W7Q10  (cfs)  W7Q10  (cfsm)                          02096500 606 60 0.0990 114 0.1881 100 0.1650                          Point of interest 1150 58.7 0.0510 154.8 0.1346 118.3 0.1029                          02096960 1275 51 0.0400 156 0.1224 113 0.0886          For the average annual discharge, an average unit flow was determined for the mean daily discharges published in Table  5 on page 76 of USGS SIR 2015‐5001 for the two reference streamgages (02096500, 02096960).  The average unit flow  was computed to be nearly 1.0 cfs per sqmi drainage area.      Average annual discharge = 1,150 cfs (equivalent to 1.0 cfs per sqmi)     Please note:     (1) The estimated flows are provided in units of cubic feet per second (cfs).  4    (2) The information provided in this message is based on a preliminary assessment and considered provisional, subject  to revision pending collection of future data and further analyses.     These provisional streamflow statistics are provided via the DWR USGS Low Flows cooperative agreement between  the USGS and the N.C. Department of Environmental Quality, Division of Water Resources.     Hope this information is helpful.     Thank you.     Curtis Weaver     J. Curtis Weaver, Hydrologist, PE Email: jcweaver@usgs.gov  USGS South Atlantic Water Science Center Online: https://www.usgs.gov/centers/sa-water  North Carolina - South Carolina - Georgia   3916 Sunset Ridge Road  Raleigh, NC 27607  Phone: (919) 571-4043 // Fax: (919) 571-4041              From: Albertin, Klaus P <klaus.albertin@ncdenr.gov>   Sent: Thursday, August 26, 2021 2:45 PM  To: Perlmutter, Gary <gary.perlmutter@ncdenr.gov>  Cc: Albertin, Klaus P <klaus.albertin@ncdenr.gov>; Hill, David A <david.hill@ncdenr.gov>; adugna.kebede@ncdenr.gov;  Weaver, John C <jcweaver@usgs.gov>; Montebello, Michael J <Michael.Montebello@ncdenr.gov>; Dowden, Doug  <doug.dowden@ncdenr.gov>  Subject: [EXTERNAL] Low‐flow request approval         This email has been received from outside of DOI ‐ Use caution before clicking on links, opening attachments, or responding.       Your request has been approved and will be forwarded to USGS. A response from USGS usually takes 7 ‐ 10 business  days.    Request Flow Statistic Approval    Request ID: 148    Requestor: Gary Perlmutter    Requestor e‐mail: gary.perlmutter@ncdenr.gov    Requestor Phone: 919‐306‐1017    Local Government:     Public Water Supply:     Consultant:   5   Contact:     Reason: Pollutant mass load allocation    River/Stream: Haw River    Drainage Area (sq. mi.): 1150    Latitude: 35.877771    Longitude: ‐79.25006    Other Information:     Statististics: ["7Q10","7Q10 ‐ Winter","30Q2","Average Annual"]    Approved by: Albertin, Klaus P    Email correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties by an authorized state official.  CAS number Method Number (if Applicable)Pollutant (Required)Reason Pollutant Believed Present in Discharge Estimated Concentration (If Known) EPA Identification Number NPDES Number Facility Name Outfall Number NC0021474 Mebane WWTP 1 No additional effluent analyses by any certified method have been conducted. All effluent analyses conducted by a certified method have been reported on each month's DMR. DATE TIME INITIALS pHALKALINITYpH @ 50mls 0.02N H2SO4 NH3-N NO3 DO TEMP pHALKALINITYpH @ 50mls 0.02N H2SO4 NH3-N NO3 DO TEMPOperating Ranges*7.0-7.6 >500 <20 <20 0.4-0.8 15-30 7.0-7.6 >500 <20 <20 0.4-0.8 15-3010/21/2019 9:01 AV/DD 7.22 >500 6.06 120 3.13 0.23 16.7 5.75 360 4 20.88 0.73 15.710/22/2019 8:16 AV/DD 7.11 >500 6.19 160 2.51 0.21 18.7 5.79 400 2 16.8 1.18 17.810/23/2019 8:04 DD 7.09 >500 150 2.77 0.24 16.2 6.61 >500 60 2.15 0.27 15.610/24/2019 9:20 AV/DD 7.2 >500 6.17 80 2.44 0.23 12.8 6.4 >500 4.88 40 9.34 0.17 11.110/25/2019 13:30 AH 7.31 >500 6.09 160 2.63 0.19 16.6 7.02 >500 5.59 90 2.17 0.12 15.5Only run DIG2-2 & aerator 4ON/4OFF until transfer from DIG1Start running another GR in DIG2 until end of day, alternate pumps each dayDIGESTER #1 DIGESTER #2COMMENTS*NOTIFY ORC IF RESULTS ARE OUTSIDE OF OPERATING RANGES 1 Coco, Nick A From:Byrd, Julia Sent:Tuesday, July 11, 2023 2:57 PM To:Coco, Nick A Subject:City of Mebane / DWI Project No. SRP-W-ARP-0177 / Water Resource Recovery Facility Expansion Project / ARPA-Earmarked Project / Letter of Intent to Fund Attachments:Mebane_SRP-W_ARP-0177_LOIF_220928.pdf Please see attached. Also, the note in the LOIF below      Julia Byrd (she/her)  Environmental Engineer II, Division of Water Infrastructure  North Carolina Department of Environmental Quality   Mobile: (828) 772‐1475  **PLEASE NOTE THE CHANGE IN EMAIL ADDRESS BELOW**  Current:  julia.byrd@deq.nc.gov  Old:   julia.byrd@ncdenr.gov       From: Newhouse, Doug <doug.newhouse@ncdenr.gov>   Sent: Thursday, September 29, 2022 10:26 AM  To: Hubbard, Mark <mark.hubbard@ncdenr.gov>; Byrd, Julia <julia.byrd@ncdenr.gov>  Subject: Fwd: City of Mebane / DWI Project No. SRP‐W‐ARP‐0177 / Water Resource Recovery Facility Expansion Project /  ARPA‐Earmarked Project / Letter of Intent to Fund  Get Outlook for iOS From: Newhouse, Doug <doug.newhouse@ncdenr.gov>  Sent: Wednesday, September 28, 2022 18:27  To: crollins@cityofmebane.com <crollins@cityofmebane.com>  Cc: Joel Whitford <joel.whitford@mcgillassociates.com>; Pohlig, Ken <ken.pohlig@ncdenr.gov>  Subject: City of Mebane / DWI Project No. SRP‐W‐ARP‐0177 / Water Resource Recovery Facility Expansion  Project / ARPA‐Earmarked Project / Letter of Intent to Fund  2    Good Evening, Mr. Rollins -- Appended to this e-mail, please find enclosed a signed, PDF copy of the Letter of Intent to Fund for the subject project. Should you require further assistance, please contact us at your convenience. Best Regards, -- Doug N.       Mebane_SRP-W_ARP-0177_LOIF_220928.pdf Doug Newhouse Engineer / Reviewer SRF Section / Wastewater Unit Division of Water Infrastructure Dept of Environmental Quality 919.707.9053 │ doug.newhouse@ncdenr.gov     Email correspondence to and from this address is subject to the North Carolina Public Records Law and may be disclosed to third parties.       Email correspondence to and from this address may be subject to the North Carolina Public Records Law and may be disclosed to third parties by an authorized state official. 4/5/2018 71.4 4/5/2018 66 5/10/2018 62.2 6/12/2018 65.9 7/19/2018 78 7/19/2018 50 8/14/2018 65.9 9/27/2018 68.6 10/11/2018 64.5 10/11/2018 70 11/29/2018 52.5 11/29/2018 14 12/13/2018 48.9 12/13/2018 31 1/10/2019 196 1/10/2019 62 2/14/2019 65.3 3/21/2019 66 4/11/2019 63 4/11/2019 50 5/16/2019 61.1 6/18/2019 77.6 7/9/2019 58.2 7/9/2019 58 7/11/2019 69.8 7/11/2019 81 8/15/2019 67.9 8/15/2019 50 9/12/2019 65.3 9/12/2019 68 10/24/2019 75.3 10/24/2019 256 11/21/2019 77.2 11/21/2019 61 1/16/2020 62.1 1/16/2019 48 2/27/2020 65.4 2/27/2020 40 3/19/2020 73.8 3/19/2020 50 4/16/2020 78.5 4/16/2020 22 5/14/2020 66.8 5/14/2020 53 6/11/2020 61.4 6/11/2020 28 7/23/2020 67.2 7/23/2020 41 8/20/2020 62.8 8/20/2020 36 9/10/2020 81.9 9/10/2020 38 10/29/2020 71.6 10/29/2020 35.1 11/17/2020 64 11/17/2020 24 12/10/2020 60 12/10/2020 21 1/14/2021 60 1/14/2021 31 4/8/2021 64 4/8/2021 48 7/5/2021 72 7/15/2021 26 10/7/2021 96 10/7/2021 39 1/13/2022 72 1/13/2022 39 4/21/2022 88 4/21/2022 2.5 *result BDL; DL=5 7/21/2022 60 7/21/2022 36 Average 71.2025 49.20625 MIN MIN 48.9 2.5 MAX MAX 196 256 41.0619 MIN 2.5 MAX 81 Effluent Hardness (mg/L)  4/1/2018‐9/30/2022 Effluent Zinc (µg/L)  4/1/2018‐9/30/2022 Average Including 10/24/19 Average Excluding 10/24/19 September 28, 2022 Mr. Chris Rollins, Manager City of Mebane 106 East Washington Street Mebane , North Carolina 27302 Subject: Letter of Intent to Fund Water Resource Recovery Facility Expansion Project American Rescue Plan – Earmark Project No.: SRP-W-ARP-0177 Dear Mr. Rollins: The Division of Water Infrastructure (Division) has reviewed your Request for Funding and determined your project is eligible to receive American Rescue Plan Act (ARPA) funding from the State Fiscal Recovery Fund (SFRF), established in Session Law (S.L.) 2022-74. Projects funded from the SFRF must meet applicable federal law and guidance for the ARPA funds. The ARPA Project Grant will be one - hundred percent (100%) of eligible project costs , up to a maximum of $11,925,000 . The first milestone is the submittal of a b id -and-design package by February 1, 2023. Please note that this intent to fund is contingent on meeting all of the following milestones: Milestone Date Apply for all Necessary Permits * ASAP Bid -and -Design Package Submittal (obtain all permits) Feb ruary 1, 2023 Bid -and -Design Package Approval June 1, 2023 Advertise Project, Receive Bids, Submit Bid Information, and Receive Authority to Award October 2, 2023 Execute Construction Contract(s) November 1, 2023 Receive Last Reimbursement - Statutory December 31, 2026 *An engineering alternatives analysis (EAA) may be required on certain projects. See: https://deq.nc.gov/about/divisions/water -resources/water -quality-permitting/npdes-wastewater/permitting-process Failure to meet any milestone may result in the forfeiture of funding for the proposed project. Note the Division will make no reimbursements of ARPA funds after December 31, 2026 . The State Environmental Policy Act exempts projects funded by the State Reserve (such as this project) from state -mandated environmental review. Federal requirements may still apply. [North Carolina General Statute (N.C.G.S.) 113A -12(2)h.] Mr. Rollins City of Mebane September 28, 2022 Page 2 of 2 Upon detailed review of the project during the funding process, it may be determined that portions of your project are not eligible for funding. US Treasury Requirements Projects with an expected total cost of ten million dollars ($10,000,000) or more must meet US Treasury requirements for prevailing-wage rates, project labor agreements, and related requirements. Recipients can either certify meeting the requirements or provide plans and reports as the SLFRF Compliance and Reporting Guidance (treasury.gov) specifies. We are offering a free , permit-assistance service to address any questions you have abo ut potential permitting requirements, pitfalls, fees, and timelines. If interested, please complete our online form at https://deq.nc.gov/permits-rules/permit-assistance -and -guidance/permit-assistance-request-form and a regional environmental coordinator will contact you. When applying for a permit , attach a copy of this letter to your permit application. We find this helpful to identify ARPA proje cts to get your permit to you faster , to assist with meeting the federal expenditure deadline of December 31, 2026. If you have any questions, please contact Julia Byrd by phone at 828 .772.1475 or by e -mail at julia.byrd@ncdenr.gov. Sincerely, Jon Risgaard, Chief State Revolving Fund Section cc: Joel Whitford, P.E., McGill Associates, P.A., Consulting Engineer (Hickory NC office) Ken Pohlig, P.E. (DWI, via e -mail) Julia Byrd (DWI, via e-mail) Mark Hubbard, P.E. (DWI, via e-mail) ARPA Project File (COM_LOIF) October 20, 2022 Mr. Nick Coco NPDES Municipal Permitting Unit 1617 Mail Service Center Raleigh, NC 27699-1617 RE: Request to Continue Reduction of Monitoring Frequencies NPDES Permit No. NC0021474 Mebane WWTP Facility Class IV Alamance County Mr. Coco, The above referenced NPDES permit authorizes discharge of treated wastewater from a designated effluent Outfall and establishes monitoring requirements. In response to your comments regarding the City of Mebane’s permit renewal application submitted November 30, 2018, please find enclosed Mebane’s request for continuation of reduction of monitoring frequencies. DWQ Guidance Regarding the Reduction of Monitoring Frequencies in NPDES Permits for Exceptionally Performing Facilities Consistent with the approval criteria listed in the guidance issued by the Division on October 22, 2012, I would like to request a continuation of reduction in the monitoring frequencies of “Twice per Week” for Biochemical Oxygen Demand [BOD5], Fecal Coliform, Total Suspended Solids [TSS], and Ammonia- Nitrogen [NH3-N]. • Overall: o Neither the City of Mebane nor any of its employees have been convicted of criminal violations of the Clean Water Act within the previous five years. o The City of Mebane WWTP is not currently under an SOC for any effluent limit noncompliance. o The City of Mebane WWTP is not on EPA’s Quarterly Noncompliance Report for any limit violations. o Reduced effluent monitoring has not impaired assessment of sensitive downstream uses, such as endangered species. o Three-year review period – January 1, 2015 through December 31, 2017 • Biochemical Oxygen Demand [BOD5]: o The facility has had zero civil penalty assessments for BOD permit limit violations during the previous three years. o Effluent BOD three year arithmetic mean = 2.62mg/L (<50% of 7.5mg/L annual arithmetic mean of seasonal Monthly Average BOD5 Permit Limits) o Number of daily BOD5 sampling results >200% of monthly average limit during three year review period = 3 o Number of non-monthly average limit violations during the previous year = 2 • Fecal Coliform: o The facility has had zero civil penalty assessments for fecal coliform permit limit violations during the previous three years. o Effluent fecal coliform three year geometric mean = 6.5/100mL (<50% of 200/100mL Monthly Average Fecal Coliform Permit Limit) o Number of daily fecal coliform sampling results >200% of weekly average limit during three year review period = 16 o Number of non-monthly average limit violations during the previous year = 0 • Total Suspended Solids [TSS]: o The facility has had zero civil penalty assessments for TSS permit limit violations during the previous three years. o Effluent TSS three year arithmetic mean = 1.33mg/L (<50% of 30.0mg/L Monthly Average TSS Permit Limit) o Number of daily TSS sampling results >200% of monthly average limit during three year review period = 0 o Number of non-monthly average limit violations during the previous year = 0 • Ammonia-Nitrogen [NH3-N]: o The facility has had zero civil penalty assessments for NH3-N permit limit violations during the previous three years. o Effluent NH3-N three year arithmetic mean = 0.93mg/L (<50% of 3.0mg/L annual arithmetic mean of seasonal Monthly Average NH3-N Permit Limit) o Number of daily NH3-N sampling results >200% of monthly average limit during three year review period = 1 o Number of non-monthly average limit violations during the previous year = 0 If you need any additional information please feel free to contact the undersigned. Thanks for your consideration and assistance in the renewal of this permit. Sincerely, Dennis J. Hodge Water Resources Director Attachment(s): MebaneReducedMonitoringData.xlsx