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HomeMy WebLinkAboutNC0020737_Fact Sheet_20231201 Fact Sheet NPDES Permit No. NCO02O737 Permit Writer/Email Contact:Nick Coco,nick.coco@deq.nc.gov Date:November 9,2023 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 Kings Mountain/Pilot Creek Wastewater Treatment Plant(WWTP) Applicant Address: P.O. Box 429,Kings Mountain,NC 28086 Facility Address: 200 Potts Creek Road,Kings Mountain,NC 28086 Permitted Flow: 6.0 MGD with interim operation tiers at 3.0 MGD and 4.0 MGD Facility Type/Waste: MAJOR Municipal; 41.8%domestic and 58.2%industrial* Facility Class: Grade IV Biological Water Pollution Control System Treatment Units: Bar Screen,Activated Sludge/Aeration, Clarification, Chlorine Disinfection,Aerobic Digestion, Sludge Dewatering Pretreatment Program(Y/N) Y; LTMP County: Cleveland Region Mooresville *Based on permitted flows(compared to 3.0 MGD flow tier) Briefly describe the proposed permitting action and facility background: The City of Kings Mountain applied for an NPDES permit renewal for the 6.0 MGD Pilot Creek WWTP and continuation of the interim operation tiers of 3.0 MGD and 4.0 MGD on March 6, 2023. The facility is rated for 6.0 MGD. The current permitted flow is 3.0 MGD and expanded flow tiers at 4.0 MGD and 6.0 MGD are permitted, taking effect once the facility demonstrates a rolling average flow for any twelve(12)month period that exceeds 2.7 MGD and 3.6 MGD,respectively. As review of the Town's discharge monitoring reports (DMRs) during the period reviewed(February 2019 to June 2023)did not demonstrate a rolling average flow for any 12-month period exceeding 2.7 MGD,the 3.0 MGD flow tier and conditions have been maintained. This facility serves a population of approximately 11,200 residents as well as 8 significant industrial users(SIU), including 7 categorical significant industrial users(CIUs),via an approved pretreatment program. Treated domestic and industrial wastewater is discharged into Buffalo Creek, a class C waterbody in the Broad River Basin. Outfall 001 is approximately 8.3 miles upstream of the NC/SC state border and approximately 0.75 miles from the Pilot Creek WWTP. Page 1 of 14 Sludge disposal: Sludge is transported to the Cleveland County Landfill for final disposal. Inflow and Infiltration(I/L. In their application,the City noted an estimated average daily I/I flow of approximately 313,000 gpd. The City has conducted collection system repairs and manhole rehabilitation that has gradually reduced the I/I experienced at the facility from 2020 through 2022. 24-hour Staffing Waiver: 15A NCAC 02H .0124(4)requires mechanical facilities with a design capacity equal to or greater than 5.0 MGD and continues operation 24 hours per day, seven days per week staffing with each shift staffed by at least one certified wastewater operator unless the applicant can demonstrate that this requirement is not necessary to ensure the reliability of unit processes. The City is currently waived of the requirement for 24-hour staffing as part of an agreement with the Division. In their application,the City provided a description of their operation process (attached) and requested continuation of the 24-hour staffing waiver. Based on review of the supporting documentation,the waiver has been continued. The Division may rescind this waiver if necessary. 2. Receiving Waterbody Information: Receiving Waterbody Information Outfalls/Receiving Stream(s): Outfall 001 -Buffalo Creek Stream Segment: 9-53-(5) Stream Classification: C Drainage Area(mi2): 116 Summer 7Q10(cfs) 19 Winter 7Q10(cfs): 42 30Q2 (cfs): 54 Average Flow(cfs): 162 IWC (%effluent): 20.0 at 3.0 MGD,24.6 at 4.0 MGD and 33.0 at 6.0 MGD 2022 303(d) listed/parameter: Not listed Subject to TMDL/parameter: Yes- State wide Mercury TMDL implementation. Basin/HUC: Broad River/03050105 USGS Topo Quad: F13SW 3. Effluent Data Summary Effluent data for Outfall 001 is summarized below for the period of February 2019 through June 2023. Table 1. Effluent Data Summary Outfall 001 Parameter Units Average Max Min Permit Limit Flow* MGD 1.6 5.894 0.456 MA 3.0 BOD summer mg/l 3.0 21.8 <2 WA 42.0 MA 28.0 BOD winter mg/1 3.3 31 <2 WA 45.0 MA 30.0 NH3N summer mg/1 0.3 12.74 <0.1 WA 7.8 MA 2.6 NH3N winter mg/1 0.5 15.3 <0.1 WA 26.7 MA 8.9 TSS mg/1 7.9 405.8 1.3 WA 45.0 MA 30.0 pH SU 6.8 7.7 6 6.0>pH<9.0 Page 2 of 14 eomean (geometric) Fecal coliform #/100 ml g 8.5 >2420 < 1 WA 400 MA 200 DO mg/l 8.4 13 5 DA>5.0 Temperature ° C 19.2 29 6.9 Monitor& Report Total Residual Chlorine µg/1 21.5 83 < 10 DM 28 TN mg/l 22.1 53.4 10.74 Monitor& Report TP mg/l 2.8 4.73 1.9 Monitor& Report Total Arsenic µg/1 62.8 210 6.8 Monitor& Report Total Cyanide µg/l 8.4 13 <5 Monitor& Report Total Molybdenum mg/I 1.9 6.4 .004 MA 10.2 DM 10.2 Total Selenium µg/l 7.1 <50 < 1 MA 25.4 DM 245.0 MA 10.2 Total Thallium µg/l 3.9 20 <0.5 DM 10.2 SOC MA 60.1 (exp. 8/31/2020) Total Hardness mg/l 136 200 12 Monitor& Report MA-Monthly Average,WA-Weekly Average,DM-Daily Maximum,DA=Daily Average *The maximum 12-month rolling average monthly flow reported during the period reviewed was 1.7 MGD. As the 12-month rolling average monthly flow did not exceed 2.7 MGD,the 4.0 MGD flow tier has not been triggered and the 3.0 MGD flow tier and limitations continue to apply. 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/1 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(YIN): NO Name of Monitoring Coalition: NA If applicable, summarize any instream data and what instream monitoring will be proposed for this permit action: The current permit requires instream monitoring for temperature, dissolved oxygen and conductivity upstream 100 yards above the outfall and downstream at NCSR 1103 (Pleasant Hill Church Road), located approximately 2.4 miles downstream of the outfall. Instream monitoring is conducted three times per week during the months of June,July,August and September then once per week during the remaining months of the year. Total hardness sampling is conducted upstream of the discharge at a Page 3 of 14 quarterly frequency. In addition to the required parameters,the City conducted instream pH monitoring. Instream data have been summarized below in Table 2. Table 2. Downstream Monitoring Data Summary Upstream Downstream Parameter Units Average Max Min Average Max Min Temperature ° C 18.8 27 6 20.3 28 7 DO mg/l 8.6 13 6.6 8.8 13.9 6.1 Conductivity µmhos/cm 69 203 27 122 468 47 pH S.U. 7.0 8.3 6.2 7.1 8.4 6.2 Total mg/1 27.4 170 16 Hardness 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. Downstream temperature was not greater than 29 degrees Celsius [per 15A NCAC 02B .0211 (18)] during the period reviewed. Downstream temperature was not greater than upstream temperature by more than 2.8 degrees Celsius during the period reviewed. It was concluded that a statistically significant difference exists between upstream and downstream temperature,with downstream temperature generally being lower than upstream temperature. While temperatures vary upstream and downstream of the discharge,no exceedance of the stream standard was observed. Monitoring has been maintained. Average downstream DO was above 5 mg/L [per 15A NCAC 02B .0211 (6)] both upstream and downstream of the discharge during the period reviewed. Instream DO was not observed at levels less than 4.0 mg/L during the period reviewed. It was concluded that a statistically significant difference exists between upstream and downstream DO. Review of instream DO showed variable differences between upstream and downstream DO,with occurrences of higher or lower downstream DO concentrations. While DO concentrations vary upstream and downstream of the discharge,no exceedance of the stream standard was observed. Monitoring has been maintained. It was concluded that a statistically significant difference exists between upstream and downstream conductivity,with downstream conductivity being consistently reported at levels higher than the upstream sample. Monitoring has been maintained. pH was not observed out of the range of 6.0 s.u. and 9.0 s.u. [per 15A NCAC 02B .0211(4)] either upstream or downstream during the period reviewed. It was concluded that a statistically significant difference exists between upstream and downstream pH. Review of instream pH showed variable differences between upstream and downstream pH,with occurrences of higher or lower downstream pH. While DO concentrations vary upstream and downstream of the discharge,no exceedance of the stream standard was observed. The City is encouraged to continue conducting ambient pH monitoring. Fecal coliform is not currently monitored instream. As the receiving stream is neither class B nor impaired for fecal coliform, and as the facility has reported no effluent fecal coliform limit violations during the period reviewed(past 5 years),no changes are proposed at this time. Page 4 of 14 5. Compliance Summary Summarize the compliance record with permit effluent limits (past 5 years): In 2018,the facility reported 1 ammonia limit violation resulting in enforcement. The facility reported 3 ammonia limit violations, 2 total residual chlorine limit violations and 3 total arsenic limit violations resulting in enforcement in 2019. In 2022,the facility reported 1 TSS limit violation resulting in enforcement. The facility reported 1 TSS limit violation resulting in enforcement in 2023. Summarize the compliance record with aquatic toxicity test limits and any second species test results (past 5 years): The facility passed 18 of 18 quarterly chronic toxicity tests, as well as all 4 second species chronic toxicity tests from January 2019 to April 2023. Summarize the results from the most recent compliance inspection: The last facility inspection conducted in October 2023 reported that the facility was not compliant.Additional information regarding the compliance issues may be found in the attached Inspection Report. The last pretreatment inspection conducted in May 2022 reported that the facility was compliant. 6. Water Quality-Based Effluent Limitations (WQBELs) Dilution and MixingZ ones 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/1 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: Limitations for summer BOD are based on a Streeter Phelps model(Level B)conducted in 1989 for instream DO protection. Limitations for winter BOD are based on Secondary Treatment Standard defined in 40 CFR 133.102. These limits are applied to all flow tiers. No changes are proposed. 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/1(summer) and 1.8 mg/1(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/1) and capped at 28 ug/l(acute impacts). Due to analytical issues,all TRC values reported below 50 ug/1 are considered compliant with their permit limit. Describe any proposed changes to ammonia and/or TRC limits for this permit renewal: The current permit requires limits and monitoring for TRC. The TRC limits have been reviewed in the attached WLA for toxicity and have been found to be protective.No changes are proposed. Page 5 of 14 Limitations for ammonia are Instream Waste Concentration(IWC)-based calculations for toxicity at the 6.0 MGD flow tier. These limits are applied to all flow tiers. The ammonia limits have been reviewed in the attached WLA for toxicity and have been found to be protective.No changes are proposed. 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%2 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. A reasonable potential analysis was conducted on effluent toxicant data collected between February 2019 and July 2023. 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: o Total Arsenic ■ @ 4.0 MGD: MA 271.3 ug/L,DM 1,200.4 ug/L ■ @ 6.0 MGD: MA 184.2 ug/L,DM 913.6 ug/L o Total Molybdenum ■ @ 6.0 MGD flow tier only: MA and DM of 6.1 mg/L o Total Thallium ■ @ 3.0 MGD: MA 10.2 ug/L,DM 10.2 ug/L ■ @ 4.0 MGD: MA 8.13 ug/L,DM 8.13 ug/L ■ @ 6.0 MGD: MA 6.1 ug/L,DM 6.1 ug/L • 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 Arsenic (@ 3.0 MGD flow tier only), Total Cadmium(@ all flow tiers), Total Chlorides (@ 6.0 MGD flow tier only), Total Cyanide(@ all flow tiers), Total Molybdenum(@ 3.0 MGD and 4.0 MGD flow tiers only); Total Selenium(@ all flow tiers), Total Silver(@ all flow tiers) • 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 Chromium, Total Copper, Total Lead, Total Nickel, Total Zinc • POTW Effluent Pollutant Scan Review: Three effluent pollutant scans (2020,2021 and 2022) 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: None 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: None 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 Page 6 of 14 Beryllium,Total Phenolic Compounds,Chloroform,Chlorodibromomethane, Dichlorobromomethane In the 2015 permit renewal, limits for thallium(1.43 µg/L monthly average and daily max)was included in the permit due to high thallium concentrations in the effluent from Pilot Creek WWTP. A Special Order of Consent(SOC) for total thallium(60.1 µg/L monthly average)was issued in July, 2016 and renewed in March 2018. This SOC expired on August 31,2020. Because the state of North Carolina did not have water quality criteria for thallium, in the 2015 permit renewal,the EPA recommended criteria of 0.47 µg/L was used for the calculation of thallium limit. In 2018,the NC Division of Water resources (DWR) conducted an assessment of thallium criteria and recommend surface water criteria for thallium as 2 µg/L in all surface waters of the state. In the 2018 permit renewal and during the current renewal process,thallium limits were recalculated based on the updated criteria value of 2 µg/L. The City reported effluent total silver at non-detect for all samples except one(4/15/2021 — 1.8 µg/L).As the only detection of total silver was reported at a value less than the most restrictive(6.0 MGD) acute allowable discharge concentration,monitoring has been added to the permit in lieu of a permit limit. The City shall monitor for total silver using a test method at least as sensitive as to be able to achieve a Practical Quantitation Level of< 1 µg/L. Since 2021,the City had conducted monitoring using a PQL of <0.5 µg/L and is encouraged to continue to use this level of sensitivity. The City reported effluent total selenium using an insufficiently sensitive test method on 7 of the 46 samples conducted during the period reviewed. These instances all occurred in 2020 and January 2021. Due to the elevated reporting levels for these 7 samples,the coefficient of variation was skewed upward in the dataset,resulting in reasonable potential for excursions above the state water quality standard at all flow tiers. Omitting these samples from the dataset,however,would conclude no reasonable potential for such excursions. As such,total selenium limits have been removed from the permit but monthly monitoring has been maintained at all flow tiers with an option for the City to request reevaluation after 12 months of sampling to reduce the monitoring frequency for total selenium to quarterly. The City shall use sufficiently sensitive test methods when monitoring for total selenium. 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: This is a Major POTW, and a chronic WET limit will continue on a quarterly frequency at an effluent concentration defined as follows: Table 3. effluent concentration for chronic WET limit Permitted flow 3.0 MGD 4.0 MGD 6.0 MGD Effluent concentration 20.0% 24.6% 33.0% Page 7 of 14 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/1)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/1) and/or if any individual value exceeds a TBEL value of 47 ng/l. Table 3. Mercury Effluent Data Summary 2019 2020 2021 2022 2023 #of Samples 3 4 4 5 3 Annual Average Conc. n /L 2.7 3.2 7.6 3.1 3 Maximum Conc.,n /L 2.94 4.62 23.2 5.18 3.29 TBEL,n /L 47 WQBEL,n /L 1 61.0 @ 3.0 MGD,48.7 @ 4.0 MGD and 36.5 @ 6.0 MGD 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 at any flow tier,no mercury limit is required. However, since the facility is>2 MGD and reported quantifiable levels of mercury(> 1 ng/1), the mercury minimization plan(MMP) condition has been maintained. Other TMDL/Nutrient Management Strategy Considerations If applicable, describe any other TMDLs/Nutrient Management Strategies and their implementation within this permit: NA 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 via a Chemical Addendum to NPDES Application table. As an attachment to the permit application, the City informed the Division that no monitoring for additional pollutants has been conducted and therefore no additional pollutants of concern have been identified. 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) Municipals (if not applicable,delete and skip to Industrials) Are concentration limits in the permit at least as stringent as secondary treatment requirements (30 mg1l BODS/TSS for Monthly Average, and 45 mg/l for BODS/TSS for Weekly Average). YES If NO,provide a justification for alternative limitations (e.g., waste stabilization pond). NA Are 85%removal requirements for BOD51TSS included in the permit? YES If NO,provide a justification (e.g., waste stabilization pond). NA Page 8 of 14 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 213.0201. 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:NA 9. Antibacksliding Review: Sections 402(o)(2) and 303(d)(4)of the CWA and federal regulations at 40 CFR 122.44(1)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): YES If YES, confirm that antibacksliding provisions are not violated: Based on the reasonable potential analysis predicting a maximum effluent total molybdenum concentration that is greater than half of the allowable discharge concentration based on state water quality standards,total molybdenum limits have been removed and monthly monitoring reduced to quarterly at the 3.0 MGD and 4.0 MGD flow tiers. The total molybdenum limits have been maintained at the 6.0 MGD flow tier. Based on review of submitted effluent total selenium data demonstrating that 7 samples reported as non- detect at insufficiently sensitive quantitation levels skew the coefficient of variation upward and drive the maximum predicted concentration upward, and that the omission of these samples results in no limit or monitoring requirement being deemed necessary, total selenium limits have been removed from the permit but monthly monitoring has been maintained at all flow tiers with an option for the City to request reevaluation after 12 months of sampling to reduce the monitoring frequency for total selenium to quarterly. The City shall use sufficiently sensitive test methods when monitoring for total selenium. 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 213.0500;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 current permit does not require effluent conductivity monitoring. As the facility receives industrial wastewater and in accordance with 15A NCAC 02B .0508, effluent conductivity monitoring has been added to the permit at a frequency of daily at all flow tiers. The current permit also does not require effluent temperature monitoring. In accordance with 15A NCAC 02B .0508, effluent temperature monitoring has been added to the permit at a frequency of daily at all flow tiers. Page 9 of 14 To better identify the triggers for activation of expanded operational tiers, a requirement to report the annual average daily flow for each calendar year has been added to the permit along with a special condition for notification of the Central and Regional Offices. 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. While there are no WS waters designated by the Division downstream of the discharge,the discharge point is approximately 8.3 miles upstream of the border between North Carolina and South Carolina. Since all waters in South Carolina are deemed suitable for drinking water uses with appropriate treatment, and to ensure PFAS contamination does not cross State lines, and as the Pilot Creek WWTP has a pretreatment program,monitoring of PFAS chemicals has been added to the permit. Currently,EPA Method 1633 is in its 4th draft form and not yet published in the Federal Register as a final methodology. As the Pilot Creek WWTP accepts influent wastewater from several industrial facilities that are potential sources of PFAS via the approved pretreatment program, and since a finalized EPA method for sampling and analyzing PFAS in wastewater is not currently available, effluent PFAS monitoring has been added to the permit at a quarterly frequency using the Draft Method 1633. Upon evaluation of laboratory availability and capability to perform the draft analytical method, it was determined that the sampling may be conducted using the 3rd draft method 1633 or more recent. Sampling using the draft method shall take effect the first full calendar quarter following 6 months after the effective date of the permit to provide the City time to select a laboratory, develop a contract, and begin collecting samples. Effective 6 months after EPA has a final wastewater method in 40 CFR136 published in the Federal Register,the City shall conduct effluent monitoring using the Final Method 1633 and is no longer required to conduct influent and post-filtration monitoring. In addition to monitoring at the wastewater management facility, the City shall identify and monitor SIUs suspected of discharging PFAS compounds within 6 months of the permit effective date. The City shall update their Industrial Waste Survey- (IWS)to identify indirect dischargers of PFAS contributing to concentrations experienced at the Pilot Creek WWTP.A summary of information learned during this process will be provided as part of the 2024 Pretreatment Annual Report(PAR). Within 6 months of completion of the IWS, the City shall begin sampling of indirect dischargers identified as potential PFAS sources. Sampling conducted at SIUs and indirect dischargers shall also be conducted at a quarterly frequency. This is a summary of the PFAS requirements. For a detailed outline of the specific PFAS requirements, see Special Condition A.(10.)PFAS Monitoring Requirements. As the Pilot Creek WWTP accepts influent wastewater from several industrial facilities that are potential sources of 1,4-dioxane via the approved pretreatment program, as no additional sampling has been conducted for 1,4-dioxane at this facility as identified in the chemical addendum submitted by the City, and as the facility discharges above the NC/SC state border line,monthly effluent monitoring for 1,4- dioxane as well as a 1,4-dioxane reopener condition have been added to the permit. After a 24-month sampling period,the Permittee may request the Division conduct a review of submitted data for assessment and approval of a 1,4-dioxane monitoring frequency reduction from monthly to quarterly. 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 extended this deadline from December 21,2020,to December 21,2025. The current compliance date, effective January 4,2021,was extended as a final regulation change published in the November 2,2020 Federal Register. This permit contains the requirements for electronic reporting, consistent with Federal requirements. Page 10 of 14 12. Summary of Proposed Permitting Actions: Table 4. Current Permit Conditions and Proposed Changes Outfall 001 Parameter Current Permit Proposed Change Basis for Condition/Change Flow MA 3.0 MGD with No change 15A NCAC 2B .0505 expansion to 4.0 MGD and 6.0 MGD Annual No requirement Report annually For tracking operational flow tier triggers Average Special Condition Flow A.(9.)Operational Flow Tier Notice BOD5 All flow tiers: No change Summer: WQBEL. 1989 Level B Model, Summer: Based on protection of DO standard. MA 28 mg/l Winter: TBEL. Secondary treatment WA 12 mg/l standards/40 CFR 133 / 15A NCAC 2B Winter: .0406. MA 30 mg/l Surface Water Monitoring, 15A NCAC WA 45 mg/l 2B. 0500 Monitor and Report Dail NH3-N All flow tiers: No change WQBEL. 2023 WLA for.6.0 MGD flow Summer: tier—applied to all flow tiers; Surface MA 2.6 mg/l Water Monitoring, 15A NCAC 2B. 0500 WA 7.8 mg/l Winter: MA 8.9 mg/l WA 26.7 mg/l Monitor and report Dail TSS All flow tiers: No change TBEL. Secondary treatment standards/40 MA 30 mg/l CFR 133 / 15A NCAC 2B .0406; Surface WA 45 mg/l Water Monitoring, 15A NCAC 2B. 0500 Monitor and report Dail Fecal All flow tiers: No change WQBEL. State WQ standard, 15A NCAC coliform MA 200/100ml 2B .0200; Surface Water Monitoring, 15A WA 400/100ml NCAC 2B. 0500 Monitor and report Dail Temperature No requirement All flow tiers: Based on instream temperature data Monitor and Report review; Surface Water Monitoring, 15A Daily NCAC 2B. 0508 DO All flow tiers: No change WQBEL. State WQ standard, 15A NCAC >5 mg/l q 2B .0200; 15A NCAC 02B .0500 Monitor and Report Daily pH All flow tiers: No change WQBEL. State WQ standard, 15A NCAC 6—9 SU 2B .0200; 15A NCAC 02B .0500 Monitor and Report Daily Total All flow tiers: No change WQBEL. 2023 WLA. Surface Water Residual DM 28 ug/L Monitoring, 15A NCAC 2B. 0500— Chlorine Monitor and Report Daily active if chlorination is used TKN No requirement All flow tiers: For calculation of TN Monitor and Report Quarterly Page 11 of 14 NO2+NO3 No requirement All flow tiers: For calculation of TN Monitor and Report Quarterly Total All flow tiers: No change Surface Water Monitoring, 15A NCAC Nitrogen Monitor and Report 2B. 0500 Quarterly Total All flow tiers: No change Surface Water Monitoring, 15A NCAC Phosphorus Monitor and Report 2B. 0500 Quarterly Conductivity All flow tiers: All flow tiers: Receives industrial waste; Surface Water No requirement Monitor and Report Monitoring, 15A NCAC 2B. 0500 Daily Total All flow tiers: No changes Hardness-dependent dissolved metals Hardness Quarterly monitoring water quality standards approved in 2016 Upstream and in Effluent Total 3.0 MGD and 4.0 MGD No change for 3.0 WQBEL-4.0 MGD and 6.0 MGD flow Arsenic flow tiers: MGD. tiers. Based on RPA; RP shown-apply Monitor and Report No change for 6.0 Monthly Monitoring with Limit. Quarterly MGD limits. 6.0 MGD flow tier: 4.0 MGD flow tier: Surface Water Monitoring 3.0 MGD. MA 184.2 ug/L MA 271.3 ug/L Based on RPA;No RP ,Predicted Max >_ DM 913.6 ug/L DM 1,200.4 u /L o g 50/o of Allowable Cw- apply Quarterly Monitor and Report Monitor and Report Monitoring Monthly Monthly Total No requirement All flow tiers: Surface Water Monitoring. Based on Cadmium Monitor and Report RPA;No RP ,Predicted Max >50%of Quarterly Allowable Cw-apply Quarterly Monitoring Total All flow tiers: No change Surface Water Monitoring. Based on Cyanide Monitor and Report RPA;No RP ,Predicted Max >50%of Quarterly Allowable Cw-apply Quarterly Monitoring Chlorides No requirement for 3.0 change 3.0 MGD and 4.0 MGD flow tiers: Based MGD and 4.0 MGD flow on RPA;No RP, Predicted Max<50%of tiers. Allowable Cw-No Monitoring required 6.0 MGD flow tier: Surface Water Monitoring-6.0 MGD. Monitor and Report Based on RPA;No RP ,Predicted Max >_ Quarterly 50%of Allowable Cw- apply Quarterly Monitoring Total 3.0 MGD flow tier: Remove limits at Surface Water Monitoring-3.0 MGD Molybdenum MA 10.2 mg/L 3.0 MGD and 4.0 and 4.0 MGD. Based on RPA;No RP , DM 10.2 mg/L MGD flow tiers Predicted Max >50%of Allowable Cw- 4.0 MGD flow tier: and reduce apply Quarterly Monitoring MA 8.13 mg/L monitoring from WQBEL-6.0 MGD. Based on RPA; RP DM 8.13 mg/L monthly to shown- apply Monthly Monitoring with 6.0 MGD flow tier: quarterly. Limit. MA 6.1 mg/L DM 6.1 mg/L All flow tiers: No change at 6.0 MGD flow tier. Page 12 of 14 Monitor and Report Monthly Total 3.0 MGD flow tier: All flow tiers: Surface Water Monitoring. 7 samples Selenium MA 25.4 ug/L Remove limits. conducted using high PQL methods skew DM 245.0 ug/L Maintain CV upward—apply monitoring; Permittee 4.0 MGD flow tier: monitoring at shall monitor at sufficiently sensitive PQL MA 20.3 ug/L monthly; add DM 197.7 ug/L option to request 6.0 MGD flow tier: reduction from MA 15.2 ug/L DM 150.5 ug/L monthly to All flow tiers: quarterly upon Monitor and Report Division approval Monthly after 12 months Total 3.0 MGD flow tier: No change WQBEL. Based on RPA; RP shown- Thallium MA 10.2 ug/L apply Monthly Monitoring with Limit. DM 10.2 ug/L 4.0 MGD flow tier: MA 8.13 ug/L DM 8.13 ug/L 6.0 MGD flow tier: MA 6.1 ug/L DM 6.1 ug/L All flow tiers: Monitor and Report Monthly Total Silver No requirement All flow tiers: Surface Water Monitoring; all values non- Monitor and Report detect except 1 value which was<DM; Quarterly Apply effluent monitoring. 1,4-Dioxane No requirement All flow tiers: Based on PT Program—industrial Monitor and Report facilities linked to 1,4-dioxane; Discharge Monthly and above NC/SC border reopener condition; 24-month sampling reassessment All flow tiers: See Special Evaluation of PFAS contribution: PFAS No requirement Condition A.(8.) pretreatment facility; Discharge above PFAS Monitoring NC/SC border Requirements and Pretreatment Toxicity Test 3.0 MGD flow tier: No change WQBEL. No toxics in toxic amounts. Chronic limit,20.0% 15A NCAC 2B.0200 and 15A NCAC effluent 2B.0500 4.0 MGD flow tier: Chronic limit, 24.6% effluent 6.0 MGD flow tier: Chronic limit, 33.0% effluent Page 13 of 14 Effluent Three times per permit No change; 40 CFR 122 Pollutant cycle conducted in 2025, Scan 2026,2027 Instream Monitor and Report for No change Surface Water Monitoring, 15A NCAC Monitoring temperature, dissolved 2B. 0508; Instream monitoring review oxygen, and conductivity 3/week during June through September and 1/week during remainder of the year Mercury MMP Special Condition No change; Consistent with 2012 Statewide Mercury Minimization Condition TMDL Implementation—multiple Plan(MMP) maintained. detections during review Electronic Electronic Reporting No change In accordance with EPA Electronic Reporting Special Condition Reporting Rule 2015. MGD—Million gallons per day,MA- Monthly Average,WA—Weekly Average,DM—Daily Max 13. Public Notice Schedule: Permit to Public Notice: xx/xx/xxxx 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.cocogdeq.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 • NPDES Implementation of Instream Dissolved Metals Standards—Freshwater Standards • NH3/TRC WLA Calculations • BOD&TSS Removal Rate Calculations • Mercury TMDL Calculations • Additional information Requested • Chemical Addendum • WET Testing and Self-Monitoring Summary Page 14 of 14 Freshwater RPA- 95% Probability/95% Confidence Using Metal Translators MAXIMUM DATA POINTS= 58 REQUIRED DATA ENTRY Table 1. Project Information Table 2. Parameters of Concern ❑CHECK IF HQW OR ORW WQS Name WQs Type Chronic Modifier Acute PQL Units Facility Name Pilot Creek WWTP Par01 Arsenic Aquactic Life C 150 FW 340 ug/L WWTP/WTP Class IV Par02 Arsenic Human Health C 10 HH/WS N/A ug/L Water Supply NPDES Permit NCO020737 Par03 Beryllium Aquatic Life NC 6.5 FW 65 ug/L Outfall 001 Par04 Cadmium Aquatic Life NC 0.9763 FW 6.1546 ug/L Flow,Qw(MGD) 3.000 Par05 Chlorides Aquatic Life NC 230 FW mg/L Receiving Stream Buffalo Creek Part) Chlorinated Phenolic Compounds Water supply NC 1 A ug/L HUC Number 03050105 Par07 0 Total Phenolic Compounds Aquatic Life NC 300 A ug/L Stream Class C Par08 Chromium III Aquatic Life NC 203.2383 FW 1652.9020 ug/L ❑Apply WS Hardness WQC Par09 Chromium VI Aquatic Life NC 11 FW 16 pg/L 7Q10s(cfs) 19.000 Par10 Chromium,Total Aquatic Life NC N/A FW N/A pg/L 7Q10w(cfs) 42.00 Par11 Copper Aquatic Life NC 13.9299 FW 20.9380 ug/L 30Q2(cfs) 54.00 Par12 Cyanide Aquatic Life NC 5 FW 22 10 ug/L QA(cfs) 162.00 Par13 Fluoride Aquatic Life NC 1,800 FW ug/L 1010s(cfs) 15.69 Par14 Lead Aquatic Life NC 6.2005 FW 171.7251 ug/L _Effluent Hardness____ 135.69 mg/L(Avg) Par15 Mercury Aquatic Life NC 12 FW 0.5 ng/L Upstream Hardness 27.4 mg/L(Avg) Par16 Molybdenum Human Health NC 2000 HH ug/L — ---------- -- _Combined Hardness Chronrl._———————48.69 mg/L ——————. I Par17 Nickel Aquatic Life NC 65.4387 FW 624.4496 pg/L Combined Hardness Acute 52.16 mg/L I Par18 Nickel Water Supply NC 25.0000 WS N/A pg/L -------------------- Data Source(s) Par19 Selenium Aquatic Life NC 5 FW 56 ug/L ❑CHECK TO APPLY MODEL Par20 Silver Aquatic Life NC 0.06 FW 1.0500 ug/L Par21 Zinc Aquatic Life NC 222.9429 FW 234.3962 ug/L Par22 Thallium Human Health NC 2 HH pg/L Par23 Chloroform Human Health C 2000 HH pg/L Par24 Chlorodibromomethane Human Health C 21 HH pg/L 20737 RPA,input 10/11/2023 Freshwater RPA- 95% Probability/95% Confidence Using Metal Translators MAXIMUM DATA POINTS= 58 REQUIRED DATA ENTRY Table 1. Project Information Table 2. Parameters of Concern ❑CHECK IF HQW OR ORW WQS Name WQs Type Chronic Modifier Acute PQL Units Facility Name Pilot Creek WWTP Par01 Arsenic Aquactic Life C 150 FW 340 ug/L WWTP/WTP Class IV Par02 Arsenic Human Health C 10 HH/WS N/A ug/L Water Supply NPDES Permit NCO020737 Par03 Beryllium Aquatic Life NC 6.5 FW 65 ug/L Outfall 001 Par04 Cadmium Aquatic Life NC 1.0563 FW 6.7589 ug/L Flow,Qw(MGD) 4.000 Par05 Chlorides Aquatic Life NC 230 FW mg/L Receiving Stream Buffalo Creek Part) Chlorinated Phenolic Compounds Water supply NC 1 A ug/L HUC Number 03050105 Par07 0 Total Phenolic Compounds Aquatic Life NC 300 A ug/L Stream Class C Par08 Chromium III Aquatic Life NC 221.3562 FW 1804.9120 ug/L ❑Apply WS Hardness WQC Par09 Chromium VI Aquatic Life NC 11 FW 16 pg/L 7Q10s(cfs) 19.000 Par10 Chromium,Total Aquatic Life NC N/A FW N/A pg/L 7Q10w(cfs) 42.00 Par11 Copper Aquatic Life NC 15.2280 FW 23.1681 ug/L 30Q2(cfs) 54.00 Par12 Cyanide Aquatic Life NC 5 FW 22 10 ug/L QA(cfs) 162.00 Par13 Fluoride Aquatic Life NC 1,800 FW ug/L 1010s(cfs) 15.69 Par14 Lead Aquatic Life NC 6.9605 FW 193.4108 ug/L _Effluent Hardness____ 135.69 mg/L(Avg) Par15 Mercury Aquatic Life NC 12 FW 0.5 ng/L Upstream Hardness 27.4 mg/L(Avg) Par16 Molybdenum Human Health NC 2000 HH ug/L — ---------- --- _Combined Hardness Chronrl._———————54.04 mg/L ——————. I Par17 Nickel Aquatic Life NC 71.4732 FW 683.8580 pg/L Combined Hardness Acute 58.07 mg/L I Par18 Nickel Water Supply NC 25.0000 WS N/A pg/L -------------------- Data Source(s) Par19 Selenium Aquatic Life NC 5 FW 56 ug/L ❑CHECK TO APPLY MODEL Par20 Silver Aquatic Life NC 0.06 FW 1.2631 ug/L Par21 Zinc Aquatic Life NC 243.5349 FW 256.7319 ug/L Par22 Thallium Human Health NC 2 HH pg/L Par23 Chloroform Human Health C 2000 HH pg/L Par24 Chlorodibromomethane Human Health C 21 HH pg/L 20737 RPA,input 10/11/2023 Freshwater RPA- 95% Probability/95% Confidence Using Metal Translators MAXIMUM DATA POINTS= 58 REQUIRED DATA ENTRY Table 1. Project Information Table 2. Parameters of Concern ❑CHECK IF HQW OR ORW WQS Name WQs Type Chronic Modifier Acute PQL Units Facility Name Pilot Creek WWTP Par01 Arsenic Aquactic Life C 150 FW 340 ug/L WWTP/WTP Class IV Par02 Arsenic Human Health C 10 HH/WS N/A ug/L Water Supply NPDES Permit NCO020737 Par03 Beryllium Aquatic Life NC 6.5 FW 65 ug/L Outfall 001 Par04 Cadmium Aquatic Life NC 1.1858 FW 7.7260 ug/L Flow,Qw(MGD) 6.000 Par05 Chlorides Aquatic Life NC 230 FW mg/L Receiving Stream Buffalo Creek Part) Chlorinated Phenolic Compounds Water supply NC 1 A ug/L HUC Number 03050105 Par07 0 Total Phenolic Compounds Aquatic Life NC 300 A ug/L Stream Class C Par08 Chromium III Aquatic Life NC 250.9357 FW 2046.5492 ug/L ❑Apply WS Hardness WQC Par09 Chromium VI Aquatic Life NC 11 FW 16 pg/L 7Q10s(cfs) 19.000 Par10 Chromium,Total Aquatic Life NC N/A FW N/A pg/L 7Q10w(cfs) 42.00 Par11 Copper Aquatic Life NC 17.3570 FW 26.7710 ug/L 30Q2(cfs) 54.00 Par12 Cyanide Aquatic Life NC 5 FW 22 10 ug/L QA(cfs) 162.00 Par13 Fluoride Aquatic Life NC 1,800 FW ug/L 1010s(cfs) 15.69 Par14 Lead Aquatic Life NC 8.2445 FW 229.0830 ug/L _Effluent Hardness 135.69 mg/L(Avg) Par15 Mercury Aquatic Life NC 12 FW 0.5 ng/L ____ Upstream Hardness 27.4 mg/L(Avg) Par16 Molybdenum Human Health NC 2000 HH ug/L — ---------- --- _Combined Hardness Chronrl._———————62.99 mg/L ——————. I Par17 Nickel Aquatic Life NC 81.3598 FW 778.6298 pg/L Combined Hardness Acute 67.7 mg/L I Par18 Nickel Water Supply NC 25.0000 WS N/A pg/L -------------------- Data Source(s) Par19 Selenium Aquatic Life NC 5 FW 56 ug/L ❑CHECK TO APPLY MODEL Par20 Silver Aquatic Life NC 0.06 FW 1.6444 ug/L Par21 Zinc Aquatic Life NC 277.2772 FW 292.3691 ug/L Par22 Thallium Human Health NC 2 HH pg/L Par23 Chloroform Human Health C 2000 HH pg/L Par24 Chlorodibromomethane Human Health C 21 HH pg/L 20737 RPA,input 10/11/2023 REASONABLE POTENTIAL ANALYSIS H1 H2 Use"PASTE SPECIAL Use"PASTE SPECIAL Effluent Hardness Values"then"COPY" Upstream Hardness Values"then"COPY" Maximum data .Maximum data points=58 points=58 Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 10/17/2019 130 130 Std Dev. 43.7687 1 3/4/2019 22 22 Std Dev. 33.6552 2 1/16/2020 100 100 Mean 135.6875 2 4/23/2019 20 20 Mean 27.4000 3 4/16/2020 140 140 C.V. 0.3226 3 7/12/2019 26 26 C.V. 1.2283 4 7/16/2020 200 200 n 16 4 10/17/2019 22 22 n 20 5 10/15/2020 130 130 10th Per value 102.00 mg/L 5 1/13/2020 20 20 10th Per value 16.00 mg/L 6 1/14/2021 140 140 Average Value 135.69 mg/L 6 4/15/2020 18 18 Average Value 27.40 mg/L 7 1/21/2021 120 120 Max. Value 200.00 mg/L 7 7/15/2020 24 24 Max. Value 170.00 mg/L 8 4/15/2021 128 128 8 10/12/2020 20 20 9 7/15/2021 136 136 9 1/12/2021 18 18 10 10/14/2021 184 184 10 1/20/2021 20 20 11 1/13/2022 168 168 11 4/12/2021 20 20 12 4/14/2022 187 187 12 7/14/2021 16 16 13 7/14/2022 12 12 13 10/12/2021 16 16 14 10/13/2022 160 160 14 1/10/2022 16 16 15 1/12/2023 132 132 15 3/11/2022 20 20 16 4/13/2023 104 104 16 4/11/2022 20 20 17 17 7/13/2022 20 20 18 18 10/11/2022 170 170 19 19 1/11/2023 20 20 20 20 4/12/2023 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 20737 RPA, data - 1 - 11/1/2023 REASONABLE POTENTIAL ANALYSIS Par01 & Par02 Use"PASTE SPECIAL Arsenic Values"then"COPY" Maximum data points=58 Date Data BDL=1/2DL Results 1 2/7/2019 140 140 Std Dev. 62.1868 2 3/7/2019 45 45 Mean 62.8143 3 4/25/2019 48 48 C.V. 0.9900 4 5/16/2019 50 50 n 28 5 6/6/2019 81 81 6 7/18/2019 130 130 Mult Factor= 1.36 7 8/8/2019 200 200 Max. Value 210.0 ug/L 8 8/15/2019 210 210 Max. Pred Cw 285.6 ug/L 9 8/29/2019 190 190 10 9/5/2019 140 140 11 10/17/2019 84 84 12 11/7/2019 54 54 13 12/5/2019 81 81 14 1/16/2020 44 44 15 4/16/2020 51 51 16 7/16/2020 37 37 17 10/15/2020 20 20 18 1/14/2021 15 15 19 1/21/2021 12 12 20 4/15/2021 15 15 21 7/15/2021 14 14 22 10/14/2021 14 14 23 1/13/2022 6.8 6.8 24 4/14/2022 11 11 25 7/14/2022 14 14 26 10/13/2022 13 13 27 1/12/2023 13 13 28 4/13/2023 26 26 29 30 31 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 20737 RPA, data -2 - 11/1/2023 REASONABLE POTENTIAL ANALYSIS Par03 Par04 Use"PASTE SPECIAL Use"PASTE SPECIAL Beryllium Values"then"COPY" Cadmium Values"then"COPY" Maximum data .Maximum data points=58 points=58 Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 1 11/17/2021 < 0.5 0.25 Std Dev. 0.1443 1 4/25/2019 < 0.5 0.25 Std Dev. 0.5232 2 4/16/2020 < 1 0.5 Mean 0.3333 2 7/18/2019 < 0.5 0.25 Mean 0.7647 3 7/30/2022 < 0.5 0.25 C.V. (default) 0.6000 3 10/17/2019 < 0.5 0.25 C.V. 0.6842 4 n 3 4 1/16/2020 < 2.5 1.25 n 18 5 5 4/16/2020 0.5 0.5 6 Mult Factor= 3.00 6 7/16/2020 < 0.5 0.25 Mult Factor= 1.47 7 Max. Value 0.50 ug/L 7 10/15/2020 1.1 1.1 Max. Value 1.910 ug/L 8 Max. Pred Cw 1.50 ug/L 8 1/14/2021 < 2.5 1.25 Max. Pred Cw 2.808 ug/L 9 9 1/21/2021 < 2.5 1.25 10 10 4/15/2021 0.68 0.68 11 11 7/15/2021 1.5 1.5 12 12 10/14/2021 0.78 0.78 13 13 1/13/2022 0.89 0.89 14 14 4/14/2022 0.58 0.58 15 15 7/14/2022 0.2 0.2 16 16 10/13/2022 < 0.15 0.075 17 17 1/12/2023 0.8 0.8 18 18 4/13/2023 1.91 1.91 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 20737 RPA, data -3- 11/1/2023 REASONABLE POTENTIAL ANALYSIS Par05 use"PASTE Par07 use"PASTE Par11 SPECIAL-Values" SPECIAL-Values" Chlorides then"COPY". Total Phenolic Compounds then"COPY". Maximum data Maximum data Date Data BDL=1/2DL Results points=58 Date Data BDL=1/2DL Results points=58 1 4/25/2019 170 170 Std Dev. 65.4758 1 10/21/2023 31 31 Std Dev. 15.7824 1 2 7/18/2019 260 260 Mean 202.6 2 4/16/2020 < 5 2.5 Mean 12.8333 2 3 10/17/2019 220 220 C.V. 0.3232 3 8/1/2022 < 10 5 C.V. (default) 0.6000 3 4 1/16/2020 82 82 n 18 4 n 3 4 5 4/16/2020 170 170 5 5 6 7/16/2020 280 280 Mult Factor= 1.2 6 Mult Factor= 3.00 6 7 10/15/2020 170 170 Max. Value 302.0 mg/L 7 Max. Value 31.0 ug/L 7 8 1/14/2021 230 230 Max. Pred Cw 368.4 mg/L 8 Max. Pred Cw 93.0 ug/L 8 9 1/21/2021 130 130 9 9 10 4/15/2021 184 184 10 10 11 7/15/2021 247 247 11 11 12 10/14/2021 302 302 12 12 13 1/13/2022 250 250 13 13 14 4/14/2022 226 226 14 14 15 7/14/2022 100 100 15 15 16 10/13/2022 287 287 16 16 17 1/12/2023 218 218 17 17 18 4/13/2023 121 121 18 18 19 19 19 20 20 20 21 21 21 22 22 22 23 23 23 24 24 24 25 25 25 26 26 26 27 27 27 28 28 28 29 29 29 30 30 30 31 31 31 32 32 32 33 33 33 34 34 34 35 35 35 36 36 36 37 37 37 38 38 38 39 39 39 40 40 40 41 41 41 42 42 42 43 43 43 44 44 44 45 45 45 46 46 46 47 47 47 48 48 48 49 49 49 50 50 50 51 51 51 52 52 52 53 53 53 54 54 54 55 55 55 56 56 56 57 57 57 58 58 58 20737 RPA, data -4- 11/1/2023 REASONABLE POTENTIAL ANALYSIS D Pall Part; Use"PASTE SPECIAL Use"PASTE SPECIAL Chromium, Total Values"then"COPY" Copper Values"then"COPY" Maximum data .Maximum data points=58 points=58 Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 4/25/2019 < 5 2.5 Std Dev. 4.3318 1 2/7/2019 3.4 3.4 Std Dev. 1.2628 1 7/18/2019 < 5 2.5 Mean 3.5294 2 3/7/2019 3.4 3.4 Mean 5.0038 2 1/16/2020 < 25 12.5 C.V. 1.2274 3 4/25/2019 3.8 3.8 C.V. 0.2524 3 4/16/2020 < 5 2.5 n 17 4 5/16/2019 6.1 6.1 n 26 4 7/16/2020 < 5 2.5 5 6/6/2019 5.9 5.9 5 10/15/2020 < 5 2.5 Mult Factor= 1.88 6 7/18/2019 6.1 6.1 Mult Factor= 1.11 6 1/14/2021 < 25 12.5 Max. Value 12.5 pg/L 7 8/8/2019 5.5 5.5 Max. Value 8.00 ug/L 7 1/21/2021 < 25 12.5 Max. Pred Cw 23.5 pg/L 8 9/5/2019 5.5 5.5 Max. Pred Cw 8.88 ug/L 8 4/15/2021 < 2 1 9 10/17/2019 4 4 9 7/15/2021 < 2 1 10 11/7/2019 4.7 4.7 10 10/14/2021 < 2 1 11 12/5/2019 2.5 2.5 11 1/13/2022 2 2 12 1/16/2020 < 10 5 12 4/14/2022 < 2 1 13 4/16/2020 4.1 4.1 13 7/14/2022 < 2 1 14 7/16/2020 3.9 3.9 14 10/13/2022 < 2 1 15 10/15/2020 4.1 4.1 15 1/12/2023 < 2 1 16 1/14/2021 < 10 5 16 4/13/2023 < 2 1 17 1/21/2021 < 10 5 17 18 4/15/2021 5 5 18 19 7/15/2021 4 4 19 20 10/14/2021 5 5 20 21 1/13/2022 7.1 7.1 21 22 4/14/2022 5 5 22 23 7/14/2022 8 8 23 24 10/13/2022 7 7 24 25 1/12/2023 5 5 25 26 4/13/2023 6 6 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 20737 RPA, data - 5- 11/1/2023 REASONABLE POTENTIAL ANALYSIS 2 Par14 Part Use"PASTE SPECIAL Use"PASTE SPECIAL Cyanide Values"then"COPY" Lead Values"then"COPY" Maximum data .Maximum data points=58 points=58 Date Data BDL=1/2DL Results Date BDL=1/2DL Results 2/7/2019 13 13 Std Dev. 2.0153 1 4/25/2019 < 2 1 Std Dev. 1.6139 1 3/7/2019 10 10 Mean 5.69 2 7/18/2019 < 2 1 Mean 2.6111 2 4/25/2019 < 10 5 C.V. 0.3540 3 10/17/2019 < 2 1 C.V. 0.6181 3 5/16/2019 < 10 5 n 26 4 1/16/2020 < 10 5 n 18 4 6/6/2019 10 10 5 4/16/2020 < 2 1 5 7/18/2019 < 10 5 Mult Factor= 1.15 6 7/16/2020 < 2 1 Mult Factor= 1.42 6 8/8/2019 < 10 5 Max. Value 13.0 ug/L 7 10/15/2020 < 2 1 Max. Value 6.000 ug/L 7 9/5/2019 < 10 5 Max. Pred Cw 15.0 ug/L 8 1/14/2021 < 10 5 Max. Pred Cw 8.520 ug/L 8 10/17/2019 < 10.0 5 9 1/21/2021 < 10 5 9 11/7/2019 < 10.0 5 10 4/15/2021 < 5 2.5 10 12/5/2019 < 10 5 11 7/15/2021 < 5 2.5 11 1/16/2020 < 10 5 12 10/14/2021 < 5 2.5 12 4/16/2020 < 10 5 13 1/13/2022 < 5 2.5 13 7/16/2020 < 10 5 14 4/14/2022 < 5 2.5 14 10/15/2020 < 10 5 15 7/14/2022 < 5 2.5 15 1/14/2021 < 10 5 16 10/13/2022 6 6 16 1/21/2021 < 10 5 17 1/12/2023 < 5 2.5 17 4/15/2021 < 5 5 18 4/13/2023 < 5 2.5 18 7/15/2021 < 5 5 19 19 10/14/2021 < 5 5 20 20 1/13/2022 < 5 5 21 21 4/14/2022 < 5 5 22 22 7/29/2022 < 5 5 23 23 10/13/2022 < 5 5 24 24 1/12/2023 < 5 5 25 25 4/13/2023 < 5 5 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 20737 RPA, data -6- 11/1/2023 REASONABLE POTENTIAL ANALYSIS 6 Par17 & Par18 Use"PASTE Part! Use"PASTE SPECIAL SPECIAL- Values"then"COPY" Values"then Molybdenum .Maximum data Nickel ..Copy... points=58 Maximum data Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results points=58 4/25/2019 630 630 Std Dev. 1363.3047 1 4/25/2019 22 22 Std Dev. 5.3058 1 7/18/2019 6200 6200 Mean 1975.8261 2 7/18/2019 30 30 Mean ##### 2 10/17/2019 2500 2500 C.V. 0.6900 3 10/17/2019 25 25 C.V. 0.3060 3 1/16/2020 430 430 n 46 4 1/16/2020 12 12 n 18 4 2/13/2020 6400 6400 5 4/16/2020 19 19 5 3/12/2020 3700 3700 Mult Factor= 1.07 6 7/16/2020 18 18 Mult Factor= 1.20 6 4/16/2020 1600 1600 Max. Value 6400.0 ug/L 7 10/15/2020 18 18 Max. Value 30.0 pg/L 7 5/7/2020 550 550 Max. Pred Cw 6848.0 ug/L 8 1/14/2021 15 15 Max. Pred Cw 36.0 pg/L 8 6/11/2020 520 520 9 1/21/2021 16 16 9 7/16/2020 1300 1300 10 4/15/2021 17 17 10 8/13/2020 910 910 11 7/15/2021 22 22 11 9/10/2020 2800 2800 12 10/14/2021 20 20 12 10/15/2020 2000 2000 13 1/13/2022 18 18 13 11/12/2020 1500 1500 14 4/14/2022 13 13 14 12/10/2020 1600 1600 15 7/14/2022 16 16 15 1/14/2021 2500 2500 16 10/13/2022 11.5 11.5 16 1/21/2021 1400 1400 17 1/12/2023 9.2 9.2 17 2/11/2021 1890 1890 18 4/13/2023 10.4 10.4 18 3/11/2021 470 470 19 19 4/15/2021 1850 1850 20 20 5/13/2021 2710 2710 21 21 6/10/2021 2950 2950 22 22 7/15/2021 3430 3430 23 23 8/12/2021 2260 2260 24 24 9/9/2021 638 638 25 25 10/14/2021 2520 2520 26 26 11/18/2021 2000 2000 27 27 12/9/2021 1640 1640 28 28 1/13/2022 1490 1490 29 29 2/8/2022 1108 1108 30 30 3/10/2022 4000 4000 31 31 4/14/2022 1360 1360 32 32 5/12/2022 3150 3150 33 33 6/9/2022 2470 2470 34 34 7/14/2022 626 626 35 35 8/11/2022 1180 1180 36 36 9/15/2022 335 335 37 37 10/13/2022 615 615 38 38 11/10/2022 2150 2150 39 39 12/8/2022 1370 1370 40 40 1/12/2023 3200 3200 41 41 2/9/2023 4010 4010 42 42 3/9/2023 1120 1120 43 43 4/13/2023 1310 1310 44 44 5/11/2023 656 656 45 45 6/8/2023 1840 1840 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 20737 RPA, data -7- 11/1/2023 REASONABLE POTENTIAL ANALYSIS 9 Par20 Par2, Use"PASTE SPECIAL- Use"PASTE SPECIAL Values"then"COPY". Values"then"COPY" Selenium Maximum data points Silver .Maximum data =58 points=58 Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results 4/25/2019 < 5 2.5 Std Dev. 5.1258 1 4/25/2019 < 1 0.5 Std Dev. 0.8619 1 7/18/2019 < 5 2.5 Mean 3.4022 2 7/18/2019 < 1 0.5 Mean 0.7944 2 10/17/2019 < 5 2.5 C.V. 1.5066 3 10/17/2019 < 1 0.5 C.V. 1.0849 3 1/16/2020 < 25 12.5 n 46 4 1/16/2020 < 5 2.5 n 18 4 2/13/2020 < 25 12.5 5 4/16/2020 < 1 0.5 5 3/12/2020 < 25 12.5 Mult Factor= 1.13 6 7/16/2020 < 1 0.5 Mult Factor= 1.73 6 4/16/2020 < 5 2.5 Max. Value 25.0 ug/L 7 10/15/2020 < 1 0.5 Max. Value 2.500 ug/L 7 5/7/2020 < 5 2.5 Max. Pred Cw 28.3 ug/L 8 1/14/2021 < 5 2.5 Max. Pred Cw 4.325 ug/L 8 6/11/2020 < 5 2.5 9 1/21/2021 < 5 2.5 9 7/16/2020 < 5 2.5 10 4/15/2021 1.8 1.8 10 8/13/2020 < 5 2.5 11 7/15/2021 < 0.5 0.25 11 9/10/2020 < 25 12.5 12 10/14/2021 < 0.5 0.25 12 10/15/2020 < 5 2.5 13 1/13/2022 < 0.5 0.25 13 11/12/2020 < 5 2.5 14 4/14/2022 < 0.5 0.25 14 12/10/2020 < 50 25 15 7/14/2022 < 0.5 0.25 15 1/14/2021 < 25 12.5 16 10/13/2022 < 0.5 0.25 16 1/21/2021 < 25 12.5 17 1/12/2023 < 0.5 0.25 17 2/11/2021 < 1 0.5 18 4/13/2023 < 0.5 0.25 18 3/11/2021 < 10 5 19 19 4/15/2021 < 10 5 20 20 5/13/2021 1 1 21 21 6/10/2021 < 1 0.5 22 22 7/15/2021 < 1 0.5 23 23 8/12/2021 < 1 0.5 24 24 9/9/2021 < 10 5 25 25 10/14/2021 < 1 0.5 26 26 11/18/2021 < 1 0.5 27 27 12/9/2021 < 1 0.5 28 28 1/13/2022 < 1 0.5 29 29 2/8/2022 < 1 0.5 30 30 3/10/2022 < 1 0.5 31 31 4/14/2022 < 1 0.5 32 32 5/12/2022 < 1 0.5 33 33 6/9/2022 < 1 0.5 34 34 7/14/2022 < 1 0.5 35 35 8/11/2022 < 1 0.5 36 36 9/15/2022 < 1 0.5 37 37 10/13/2022 < 1 0.5 38 38 11/10/2022 < 1 0.5 39 39 12/8/2022 < 1 0.5 40 40 1/12/2023 < 1 0.5 41 41 2/9/2023 < 1 0.5 42 42 3/9/2023 < 1 0.5 43 43 4/13/2023 2 2 44 44 5/11/2023 < 1 0.5 45 45 6/8/2023 2 2 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 20737 RPA, data -8- 11/1/2023 REASONABLE POTENTIAL ANALYSIS 1 Par22 use"PASTE Par2: Use"PASTE SPECIAL Values"then"COPY" SPECIAL-Values" Zinc Maximum data Thallium then"COPY". points=58 Maximum data Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results points=58 2/7/2019 33 33 Std Dev. 12.3921 1 2/7/2019 6.6 6.6 Std Dev. 2.4227 1 3/7/2019 34 34 Mean 36.7308 2 3/7/2019 3.5 3.5 Mean 3.0309 2 4/25/2019 38 38 C.V. 0.3374 3 4/25/2019 4.1 4.1 C.V. 0.7993 3 5/16/2019 61 61 n 26 4 5/16/2019 6.4 6.4 n 55 4 6/6/2019 49 49 5 6/6/2019 8.5 8.5 5 7/18/2019 58 58 Mult Factor= 1.14 6 7/18/2019 7.3 7.3 Mult Factor= 1.02 6 8/8/2019 39 39 Max. Value 64.0 ug/L 7 8/8/2019 6.9 6.9 Max. Value 10.0 pg/L 7 9/5/2019 53 53 Max. Pred Cw 73.0 ug/L 8 9/5/2019 4 4 Max. Pred Cw 10.2 pg/L 8 10/17/2019 25 25 9 10/17/2019 < 2 1 9 11/7/2019 31 31 10 11/7/2019 < 2 1 10 12/5/2019 36 36 11 12/5/2019 < 2 1 11 1/16/2020 < 50 25 12 1/16/2020 < 10 5 12 4/16/2020 55 55 13 2/13/2020 < 10 5 13 7/16/2020 36 36 14 3/12/2020 < 10 5 14 10/15/2020 28 28 15 4/16/2020 2.3 2.3 15 1/14/2021 < 50 25 16 5/7/2020 2.2 2.2 16 1/21/2021 < 50 25 17 6/11/2020 3.2 3.2 17 4/15/2021 43 43 18 7/16/2020 2.7 2.7 18 7/15/2021 30 30 19 7/31/2020 2.8 2.8 19 10/14/2021 25 25 20 8/13/2020 4.7 4.7 20 1/13/2022 64 64 21 9/10/2020 < 10 5 21 4/14/2022 30 30 22 10/15/2020 < 2 1 22 7/14/2022 29 29 23 11/12/2020 < 2 1 23 10/13/2022 33 33 24 12/10/2020 < 20 10 24 1/12/2023 25 25 25 1/14/2021 < 10 5 25 4/13/2023 25 25 26 1/21/2021 < 10 5 26 27 2/11/2021 0.8 0.8 27 28 3/11/2021 2.2 2.2 28 29 4/15/2021 2.4 2.4 29 30 5/13/2021 2.1 2.1 30 31 6/10/2021 2.3 2.3 31 32 7/15/2021 2.4 2.4 32 33 8/12/2021 3 3 33 34 9/9/2021 2.5 2.5 34 35 10/14/2021 2.2 2.2 35 36 11/18/2021 1.1 1.1 36 37 12/9/2021 0.8 0.8 37 38 1/13/2022 3.9 3.9 38 39 2/8/2022 1.2 1.2 39 40 3/10/2022 6.2 6.2 40 41 4/14/2022 1.2 1.2 41 42 5/12/2022 < 5 2.5 42 43 6/9/2022 1.6 1.6 43 44 7/14/2022 2 2 44 45 8/11/2022 2 2 45 46 9/15/2022 < 0.5 0.25 46 47 10/13/2022 1.2 1.2 47 48 11/10/2022 1 1 48 49 12/8/2022 0.7 0.7 49 50 1/12/2023 < 0.5 0.25 50 51 2/9/2023 < 0.5 0.25 51 52 3/9/2023 0.6 0.6 52 53 4/13/2023 < 0.5 0.25 53 54 5/11/2023 0.6 0.6 54 55 6/8/2023 9 9 55 56 56 57 57 58 58 20737 RPA, data -9- 11/1/2023 REASONABLE POTENTIAL ANALYSIS 3 Par24 use"PASTE Part! Use"PASTE SPECIAL Values"then"COPY" SPECIAL-Values" Chloroform .Maximum data Chlorodibromomethane then"COPY". points=58 Maximum data Date Data BDL=1/2DL Results Date Data BDL=1/2DL Results points=58 10/19/2021 15.3 15.3 Std Dev. 7.1218 1 10/19/2021 17.3 17.3 Std Dev. 5.0083 1 4/16/2020 5.1 5.1 Mean 7.3 2 4/16/2020 7.3 7.3 Mean 12.4667 2 7/29/2022 1.59 1.59 C.V. (default) 0.6 3 7/29/2022 12.8 12.8 C.V. (default) 0.6000 3 n 3 4 n 3 4 5 5 Mult Factor= 3.00 6 Mult Factor= 3.00 6 Max. Value 15 lag/L 7 Max. Value 17.300000 lag/L 7 Max. Pred Cw 46 lag/L 8 Max. Pred Cw 51.900000 lag/L 8 9 9 10 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 20737 RPA, data - 10 - 11/1/2023 REASONABLE POTENTIAL ANALYSIS 5 Use"PASTE SPECIAL- Dichlorobromomethane Values"then"COPY" Maximum data points=58 Date Data BDL=1/2DL Results 10/19/2021 15.1 15.1 Std Dev. 5.6945 4/16/2020 5.6 5.6 Mean 8.5367 7/29/2022 4.91 4.91 C.V. (default) 0.6000 n 3 Mult Factor= 3.00 Max. Value 15.100000 tag/L Max. Pred Cw 45.300000 Ng/L 20737 RPA, data - 11 - 11/1/2023 Pilot Creek WWTP > Outfall 001 NCOO2O737 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 3 MGD MAXIMUM DATA POINTS = 58 Qw (MGD) = 3.0000 WWTP/WTP Class: IV COMBINED HARDNESS (mg/L) 1Q10S (cfs) = 15.69 IWC% @ 1QlOS = 22.86135693 Acute =52.16 mg/L 7Q10S (cfs) = 19.00 IWC% @ 7Q10S = 19.66173362 Chronic =48.69 mg/L 7Q10W (cfs) = 42.00 IWC% @ 7Q10W= 9.967845659 30Q2 (cfs) = 54.00 IWC% @ 30Q2 = 7.928388747 Avg. Stream Flow, QA(cfs) = 162.00 IW%C @ QA= 2.790279028 Receiving Stream: Buffalo Creek HUC 03050105 Stream Class: C PARAMETER NC STANDARDS OR EPA CRITERIA J REASONABLE POTENTIAL RESULTS RECOMMENDED ACTION TYPE Chronic Standard Acute a. D n #Det. Max Pred Cw Allowable Cw Acute (FW): 1,487.2 Arsenic C 150 FW(7Q10s) 340 ug/L 28 28 285.E Chronic (FW):--- 762.9 -No value >Allowable Cw Arsenic C 10 HH/WS(Qavg) ug/L Chronic (HH): 358.4 No RP , Predicted Max >_ 50% of Allowable Cw- No value >Allowable Cw apply Quarterly Monitoring Acute: 284.32 Beryllium NC 6.5 FW(7Q10s) 65 ug/L 3 0 1.50 Note: n<9 C.V. (default) Chronic: 33.06 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set NO DETECTS Max MDL= 1 Monitoring required Acute: 26.921 Cadmium NC 0.9763 FW(7QIOs) 6.1546 ug/L 18 10 2.808 _ _____ _ _ Chronic 4.966 No RP , Predicted Max >_ 50% of Allowable Cw No value >Allowable Cw apply Quarterly Monitoring Acute: NO WQS Chlorides NC 230 FW(7010s) ma/L 18 18 368.4 _ Chronic 1,169.8 No RP, Predicted Max< 50% of Allowable Cw- No No value >Allowable Cw Monitoring required Acute: NO WQS Total Phenolic Compounds NC 300 A(30Q2) ug/L 3 1 93.0 Note: n<9 C.V. (default) Chronic: 3,783.9 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value >Allowable Cw Monitoring required Acute: 7,230.1 Chromium III NC 203.24 FW(7Q10s) 1652.90 µg/L 0 0 N/A Chronic: 1,033.7 Acute: 70.0 Chromium VI NC 11 FW(7QIOs) 16 µg/L 0 0 N/A Chronic: 55.9 Tot Cr value(s) > 5 but< Cr VI Allowable Cw a: No monitoring required if all Total Chromium Chromium, Total NC µg/L 17 1 23.5 Max reported value 12.5 samples are < 5 pg/L or Pred. max for Total Cr is < allowable Cw for Cr VI. Acute: 91.59 Copper NC 13.9299 FW(7O10s) 20.9380 u4/L 26 23 8.88 Chronic: 70.85 No RP, Predicted Max< 50% of Allowable Cw- No No value >Allowable Cw IMonitoring required 20737 RPA, rpa Page 1 of 2 11/1/2023 Pilot Creek WWTP > Outfall 001 NCO020737 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 3 MGD Acute: 96.2 Cyanide NC 5 FW(7010s) 22 10 u4/L 26 3 15.0 _ ----------------------------- No RP , Predicted Max >_ 50% of Allowable Cw- No value>Allowable Cw apply Quarterly Monitoring Acute: 751.159 Lead NC 6.2005 FW(7Q10s) 171.7251 ug/L 18 1 8.520 Chronic: 31.536 No RP, Predicted Max< 50% of Allowable Cw- No No value>Allowable Cw Monitoring required Acute: NO WQS Molybdenum NC 2000 HH(7Q10s) ug/L 46 46 6,848.0 Chronic: 10,172.0 No RP , Predicted Max >_ 50% of Allowable Cw- No value>Allowable Cw defer to LTMP Acute (FW): 2,731.5 Nickel NC 65.4387 FW(7Q10s) 624.4496 µg/L 18 18 36.0 Chronic (FW): 332.8 No RP, Predicted Max< 50% of Allowable Cw- No No value > Allowable Cw Monitoring required Nickel NC 25.0000 WS(7Q10s) µg/L Chronic (WS): 127.2 No value>Allowable Cw Acute: 245.0 Selenium NC 5 FW(7Q10s) 56 ug/L 46 3 28.3 _ Chronic 25.4 BPJ; 7 samples conducted using high PQL methods No value> Allowable Cw skew CV upward -apply quarterly monitoring Acute: 4.593 Silver NC 0.06 FW(7Q10s) 1.0500 ug/L 18 1 4.325 Chronic: 0.305 BPJ; One detection in dataset; value < DM -Apply quarterly monitoring 10 values >Allowable Cw Acute: 1,025.3 No RP, Predicted Max< 50% of Allowable Cw- No Zinc NC 222.9429 FW(7Q10s) 234.3962 ug/L 26 23 73.0 Monitoring required ---- - ----------------------------- Chronic: 1,133.9 No value>Allowable Cw Acute: NO WQS Thallium NC 2 HH(7Q10s) µg/L 55 38 10.20000 Chronic: ---- 10.172 - ----------------------------- RP shown-apply Monthly Monitoring with Limit No value>Allowable Cw ----------------------------- Acute: NO WQS Chloroform C 2000 HH(Qavg) µg/L 3 3 45.90000 _ Note: n<9 C.V. (default) Chronic 71677.41935 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required Acute: NO WQS Chlorodibromomethane C 21 HH(Qavg) µg/L 3 3 51.90000 Note: n<9 C.V. (default) Chronic: 752.61290 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required Acute: NO WQS Dichlorobromomethane C 17 HH(Qavg) µg/L 3 3 45.30000 _ Note: n<9 C.V. (default) Chronic 609.25806 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required 20737 RPA, rpa Page 2 of 2 11/1/2023 Pilot Creek WWTP > Outfall 001 NCO020737 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 4 MGD MAXIMUM DATA POINTS = 58 Qw (MGD) = 4.0000 WWTP/WTP Class: IV COMBINED HARDNESS (mg/L) 1Q10S (cfs) = 15.69 IWC% @ 1Q10S = 28.32343536 Acute =58.07 mg/L 7Q10S (cfs) = 19.00 IWC% @ 7Q10S = 24.6031746 Chronic = 54.04 mg/L 7QIOW (cfs) = 42.00 IWC% @ 7Q10W= 12.86307054 30Q2 (cfs) = 54.00 IWC% @ 30Q2 = 10.29900332 Avg. Stream Flow, QA(cfs) = 162.00 IW%C @ QA= 3.68608799 Receiving Stream: Buffalo Creek HUC 03050105 Stream Class: C PARAMETER NC STANDARDS OR EPA CRITERIA J REASONABLE POTENTIAL RESULTS RECOMMENDED ACTION TYPE Chronic Standard Acute a. D n #Det. Max Pred Cw Allowable Cw Acute (FW): 1,200.4 Arsenic C 150 FW(7Q10s) 340 ug/L 28 28 285.E Chronic (FW):--- 609.7 - ----------------------------- No_value >Allowable C_w __ Arsenic C 10 HH/WS(Qavg) ug/L Chronic (HH): 271.3 RP shown-apply Monthly Monitoring with Limit No value >Allowable Cw Acute: 229.49 Beryllium NC 6.5 FW(7Q10s) 65 ug/L 3 0 1.50 Note: n<9 C.V. (default) Chronic: 26.42 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set NO DETECTS Max MDL= ] Monitoring required Acute: 23.863 Cadmium NC 1.0563 FW(7Q10s) 6.7589 ug/L 18 10 2.808 _ _____ __ _ Chronic 4.293 No RP , Predicted Max >_ 50% of Allowable Cw No value >Allowable Cw apply Quarterly Monitoring Acute: NO WQS Chlorides NC 230 FW(7010s) ma/L 18 18 368.4 _ Chronic 934.8 No RP, Predicted Max< 50% of Allowable Cw- No No value >Allowable Cw Monitoring required Acute: NO WQS Total Phenolic Compounds NC 300 A(30Q2) ug/L 3 1 93.0 Note: n<9 C.V. (default) Chronic: 2,912.9 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value >Allowable Cw Monitoring required Acute: 6,372.5 Chromium III NC 221.36 FW(7Q10s) 1804.91 µg/L 0 0 N/A Chronic: 899.7 Acute: 56.5 Chromium VI NC 11 FW(7Q10s) 16 µg/L 0 0 N/A Chronic: 44.7 Tot Cr value(s) > 5 but< Cr VI Allowable Cw a: No monitoring required if all Total Chromium Chromium, Total NC µg/L 17 1 23.5 Max reported value 12.5 samples are < 5 pg/L or Pred. max for Total Cr is < allowable Cw for Cr VI. Acute: 81.80 Copper NC 15.2280 FW(7010s) 23.1681 u4/L 26 23 8.88 Chronic: 61.89 No RP, Predicted Max< 50% of Allowable Cw- No No value >Allowable Cw IMonitoring required 20737 RPA, rpa Page 1 of 2 11/1/2023 Pilot Creek WWTP > Outfall 001 NCO020737 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 4 MGD Acute: 77.7 Cyanide NC 5 FW(7010s) 22 10 u4/L 26 3 15.0 _ ----------------------------- No RP , Predicted Max >_ 50% of Allowable Cw- No value>Allowable Cw apply Quarterly Monitoring Acute: 682.865 Lead NC 6.9605 FW(7Q10s) 193.4108 ug/L 18 1 8.520 Chronic: 28.291 No RP, Predicted Max< 50% of Allowable Cw- No No value>Allowable Cw Monitoring required Acute: NO WQS Molybdenum NC 2000 HH(7Q10s) ug/L 46 46 6,848.0 Chronic: 8,129.0 No RP , Predicted Max >_ 50% of Allowable Cw- No value>Allowable Cw defer to LTMP Acute (FW): 2,414.5 Nickel NC 71.4732 FW(7Q10s) 683.8580 µg/L 18 18 36.0 Chronic (FW): 290.5 No RP, Predicted Max< 50% of Allowable Cw- No No value>Allowable Cw Monitoring required Nickel NC 25.0000 WS(7Q10s) µg/L Chronic (WS): 101.6 No value>Allowable Cw Acute: 197.7 Selenium NC 5 FW(7Q10s) 56 ug/L 46 3 28.3 _ Chronic 20.3 BPJ; 7 samples conducted using high PQL methods 1 value(s) >Allowable Cw skew CV upward -apply quarterly monitoring Acute: 4.459 Silver NC 0.06 FW(7Q10s) 1.2631 ug/L 18 1 4.325 Chronic: 0.244 BPJ; One detection in dataset; value < DM -Apply quarterly monitoring 18 values >Allowable Cw Acute: 906.4 No RP, Predicted Max< 50% of Allowable Cw- No Zinc NC 243.5349 FW(7Q10s) 256.7319 ug/L 26 23 73.0 Monitoring required ----- --- - ----------------------------- Chronic No value>Allowable Cw Acute: NO WQS Thallium NC 2 HH(7Q10s) µg/L 55 38 10.20000 Chronic: ---- 8.129 - ----------------------------- RP shown-apply Monthly Monitoring with Limit 3 values >Allowable Cw Acute: NO WQS ----------------------------- Chloroform C 2000 HH(Qavg) µg/L 3 3 45.90000 Note: n<9 C.V. (default) Chronic: 54258.06452 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required Acute: NO WQS Chlorodibromomethane C 21 HH(Qavg) µg/L 3 3 51.90000 Note: n<9 C.V. (default) Chronic: 569.70968 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required Acute: NO WQS Dichlorobromomethane C 17 HH(Qavg) µg/L 3 3 45.30000 _ Note: n<9 C.V. (default) Chronic 461.19355 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required 20737 RPA, rpa Page 2 of 2 11/1/2023 Pilot Creek WWTP > Outfall 001 NCO020737 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) = 15.69 IWC% @ 1Q10S = 37.21488595 Acute =67.7 mg/L 7Q10S (cfs) = 19.00 IWC% @ 7Q10S = 32.86219081 Chronic = 62.99 mg/L 7Q10W (cfs) = 42.00 IWC% @ 7Q10W= 18.12865497 30Q2 (cfs) = 54.00 IWC% @ 30Q2 = 14.69194313 Avg. Stream Flow, QA(cfs) = 162.00 IW%C @ QA= 5.429071804 Receiving Stream: Buffalo Creek HUC 03050105 Stream Class: C PARAMETER NC STANDARDS OR EPA CRITERIA J REASONABLE POTENTIAL RESULTS RECOMMENDED ACTION TYPE Chronic Standard Acute a. D n #Det. Max Pred Cw Allowable Cw Acute (FW): 913.6 Arsenic C 150 FW(7Q10s) 340 ug/L 28 28 285.E Chronic (FW):--- 456.5-- ----------------------------- No_value >Allowable C_w __ Arsenic C 10 HH/WS(Qavg) ug/L Chronic (HH): 184.2 RP shown-apply Monthly Monitoring with Limit 3 values >Allowable Cw Acute: 174.66 Beryllium NC 6.5 FW(7Q10s) 65 ug/L 3 0 1.50 Note: n<9 C.V. (default) Chronic: 19.78 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set NO DETECTS Max MDL= 1 Monitoring required Acute: 20.760 Cadmium NC 1.1858 FW(7Q10s) 7.7260 ug/L 18 10 2.808 Chronic: 3.608 No RP , Predicted Max >_ 50% of Allowable Cw- No value >Allowable Cw apply Quarterly Monitoring Acute: NO WQS Chlorides NC 230 FW(7010s) ma/L 18 18 368.4 _ Chronic 699.9 No RP , Predicted Max >_ 50% of Allowable Cw- No value >Allowable Cw apply Quarterly Monitoring Acute: NO WQS Total Phenolic Compounds NC 300 A(30Q2) ug/L 3 1 93.0 Note: n<_9 C.V. (default) Chronic: 2,041.9 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value >Allowable Cw Monitoring required Acute: 5,499.3 Chromium III NC 250.94 FW(7Q10s) 2046.55 µg/L 0 0 N/A Chronic: 763.6 Acute: 43.0 Chromium VI NC 11 FW(7Q10s) 16 µg/L 0 0 N/A Chronic: 33.5 Tot Cr value(s) > 5 but< Cr VI Allowable Cw a: No monitoring required if all Total Chromium Chromium, Total NC µg/L 17 1 23.5 Max reported value 12.5 samples are < 5 pg/L or Pred. max for Total Cr is < allowable Cw for Cr VI. Acute: 71.94 Copper NC 17.3570 FW(7010s) 26.7710 u4/L 26 23 8.88 Chronic: 52.82 No RP, Predicted Max< 50% of Allowable Cw- No No value >Allowable Cw Monitoring required 20737 RPA, rpa Page 1 of 2 11/1/2023 Pilot Creek WWTP > Outfall 001 NCO020737 Freshwater RPA - 95% Probability/95% Confidence Using Metal Translators Qw = 6 MGD Acute: 59.1 Cyanide NC 5 FW(7010s) 22 10 u4/L 26 3 15.0 _ ----------------------------- No RP , Predicted Max >_ 50% of Allowable Cw- No value>Allowable Cw apply Quarterly Monitoring Acute: 615.568 Lead NC 8.2445 FW(7Q10s) 229.0830 ug/L 18 1 8.520 Chronic: 25.088 No RP, Predicted Max< 50% of Allowable Cw- No No value>Allowable Cw Monitoring required Acute: NO WQS Molybdenum NC 2000 HH(7Q10s) ug/L 46 46 6,848.0 Chronic: 6,086.0 RP shown-apply Monthly Monitoring with Limit 2 value(s) >Allowable Cw Acute (FW): 2,092.3 Nickel NC 81.3598 FW(7Q10s) 778.6298 µg/L 18 18 36.0 Chronic (FW): 247.6 No RP, Predicted Max< 50% of Allowable Cw- No No value>Allowable Cw Monitoring required Nickel NC 25.0000 WS(7Q10s) µg/L Chronic (WS): 76.1 No value>Allowable Cw Acute: 150.5 Selenium NC 5 FW(7Q l Os) 56 ug/L 46 3 28.3 _ Chronic 15.2 BPJ; 7 samples conducted using high PQL methods 1 value(s) >Allowable Cw skew CV upward -apply quarterly monitoring Acute: 4.419 Silver NC 0.06 FW(7Q10s) 1.6444 ug/L 18 1 4.325 Chronic: 0.183 BPJ; One detection in dataset; value < DM -Apply quarterly monitoring 18 values >Allowable Cw Acute: 785.6 No RP, Predicted Max< 50% of Allowable Cw- No Zinc NC 277.2772 FW(7Q10s) 292.3691 ug/L 26 23 73.0 Monitoring required ----- --- - ----------------------------- Chronic No value>Allowable Cw Acute: NO WQS Thallium NC 2 HH(7Q10s) µg/L 55 38 10.20000 Chronic: 6.086 RP shown-apply Monthly Monitoring with Limit 8 values >Allowable Cw Acute: NO WQS ----------------------------- Chloroform C 2000 HH(Qavg) µg/L 3 3 45.90000 Note: n<9 C.V. (default) Chronic: 36838.70968 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required Acute: NO WQS Chlorodibromomethane C 21 HH(Qavg) µg/L 3 3 51.90000 Note: n<9 C.V. (default) Chronic: 386.80645 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value>Allowable Cw Monitoring required Acute: NO WQS Dichlorobromomethane C 17 HH(Qavg) µg/L 3 3 45.30000 _ Note: n<9 C.V. (default) Chronic 313.12903 No RP, Predicted Max< 50% of Allowable Cw- No Limited data set No value >Allowable Cw Monitoring required 20737 RPA, rpa Page 2 of 2 11/1/2023 Permit No. NCO020737 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 Q ality Standards/A uatic Life Protection Parameter Acute FW, µg/l Chronic FW, µg/l Acute SW, µg/1 Chronic SW, µg/1 (Dissolved) (Dissolved) (Dissolved) (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/1 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/I Cadmium,Acute WER*{1.136672-[ln hardness](0.041838)} e^10.9151 [ln hardness]-3.1485} Cadmium,Acute Trout waters WER*{1.136672-[ln hardness](0.041838)} e^{0.9151[In hardness]-3.62361 Cadmium,Chronic WER*{1.101672-[ln hardness](0.041838)} •e^{0.7998[ln hardness]-4.445 11 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} Page 1 of 4 Permit No. NCO020737 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/WOBELs 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 1 Q 10 using the formula 1 Q 10=0.843 (s7Q 10, 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. Page 2 of 4 Permit No. NCO020737 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 IQ 10 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. 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 I + { [Kpo] [ss('+a)] [10-6] } Where: ss=in-stream suspended solids concentration [mg/1],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. 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=(s7Q 10+Qw)(Cwgs)—(s7Q 10) (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 s7Q 10) s7Q 10=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 s7Q 10 may be incorporated as applicable: IQ 10=used in the equation to protect aquatic life from acute toxicity Page 3 of 4 Permit No. NC0020737 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) 135.69 Average from 312019 to 412023 [Total as, CaCO3 or(Ca+Mg)] samples Average Upstream Hardness (mg/L) 27.4 Average from 312019 to 412023 [Total as, CaCO3 or(Ca+Mg)] samples 7Q10 summer(cfs) 19.0 Historical;Previous Fact Sheet 1Q10(cfs) 15.69 Calculated in RPA Permitted Flow(MGD) 6.0 MGD with NPDES Files operation tiers at 3.0 MGD and 4.0 MGD Date: 10/11/2023 Permit Writer: Nick Coco Page 4 of 4 NH3/TRC WLA Calculations Facility: Pilot Creek WWTP PermitNo. NC0020737 Prepared By: Nick Coco Enter Design Flow (MGD): 6 Enter s7Q10 (cfs): 19 Enter w7Q10 (cfs): 42 Total Residual Chlorine (TRC) Ammonia (Summer) Daily Maximum Limit(ug/1) Monthly Average Limit (mg NH3-N/1) s7Q10 (CFS) 19 s7Q10 (CFS) 19 DESIGN FLOW (MGD) 6 DESIGN FLOW (MGD) 6 DESIGN FLOW (CFS) 9.3 DESIGN FLOW (CFS) 9.3 STREAM STD (UG/L) 17.0 STREAM STD (MG/L) 1.0 Upstream Bkgd (ug/1) 0 Upstream Bkgd (mg/1) 0.22 IWC (%) 32.86 IWC (%) 32.86 Allowable Conc. (ug/1) 52 Allowable Conc. (mg/1) 2.6 Cap at 28 ug/L.Consistent with current limit.Maintain Limit. Consistent with current limit.Maintain limit. Applied to all flow tiers. Applied to all flow tiers. Ammonia (Winter) Monthly Average Limit (mg NH3-N/1) Fecal Coliform w7Q10 (CFS) 42 Monthly Average Limit: 200/100m1 DESIGN FLOW (MGD) 6 (If DF >331; Monitor) DESIGN FLOW (CFS) 9.3 (If DF<331; Limit) STREAM STD (MG/L) 1.8 Dilution Factor(DF) 3.04 Upstream Bkgd (mg/1) 0.22 IWC (%) 18.13 Allowable Conc. (mg/1) 8.9 Consistent with current limit.Maintain limit. Applied to all flow tiers. Total Residual Chlorine 1. Cap Daily Max limit at 28 ug/I 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) MONITORING REPORT(MR)VIOLATIONS for: Report Date: 08/31/22 Page 1 of 15 Permit: NCO020737 MRS Betweei 8 - 2018 and 8 - 2023 Region: % Violation Category:Limit Violation Program Category: Facility Name:% Param Nam(% County: % Subbasin:% Violation Action:% Major Minor: % PERMIT: NCO020737 FACILITY: City of Kings Mountain-Pilot Creek WWTP COUNTY: Cleveland REGION: Mooresville Limit Violation MONITORING VIOLATION UNIT OF CALCULATED % REPORT OUTFALL LOCATION PARAMETER DATE FREQUENCY MEASURE LIMIT VALUE Over VIOLATION TYPE VIOLATION ACTION 08-2019 001 Effluent Arsenic,Total(as As) 08/08/19 Monthly ug/I 184.2 200 8.6 Daily Maximum Proceed to Exceeded Enforcement Case 08-2019 001 Effluent Arsenic,Total(as As) 08/15/19 Monthly ug/I 184.2 210 14.0 Daily Maximum Proceed to Exceeded Enforcement Case 08-2019 001 Effluent Arsenic,Total(as As) 08/29/19 Monthly ug/I 184.2 190 3.1 Daily Maximum No Action, BPJ Exceeded 08-2019 001 Effluent Arsenic,Total(as As) 08/31/19 Monthly ug/I 152.2 200 31.4 Monthly Average No Action, BPJ Exceeded 08-2019 001 Effluent Arsenic,Total(as As) 08/31/19 Monthly ug/I 152.2 205 34.7 Monthly Average Proceed to Exceeded Enforcement Case 08-2018 001 Effluent Chlorine,Total Residual 08/02/18 5 X week ug/I 28 29 3.6 Daily Maximum No Action, BPJ Exceeded 08-2018 001 Effluent Chlorine,Total Residual 08/22/18 5 X week ug/I 28 31 10.7 Daily Maximum No Action, BPJ Exceeded 08-2018 001 Effluent Chlorine,Total Residual 08/24/18 5 X week ug/I 28 29 3.6 Daily Maximum No Action, BPJ Exceeded 09-2018 001 Effluent Chlorine,Total Residual 09/04/18 5 X week ug/I 28 31 10.7 Daily Maximum No Action, BPJ Exceeded 09-2018 001 Effluent Chlorine,Total Residual 09/06/18 5 X week ug/I 28 31 10.7 Daily Maximum No Action, BPJ Exceeded 09-2018 001 Effluent Chlorine,Total Residual 09/21/18 5Xweek ug/I 28 34 21.4 Daily Maximum No Action, BPJ Exceeded 10-2018 001 Effluent Chlorine,Total Residual 10/17/18 5 X week ug/I 28 29 3.6 Daily Maximum No Action, BPJ Exceeded 11-2018 001 Effluent Chlorine,Total Residual 11/01/18 5 X week ug/I 28 32 14.3 Daily Maximum No Action, BPJ Exceeded 11-2018 001 Effluent Chlorine,Total Residual 11/19/18 5 X week ug/I 28 29 3.6 Daily Maximum No Action, BPJ Exceeded 12-2018 001 Effluent Chlorine,Total Residual 12/03/18 5 X week ug/I 28 29 3.6 Daily Maximum No Action, BPJ Exceeded 12-2018 001 Effluent Chlorine,Total Residual 12/04/18 5 X week ug/I 28 32 14.3 Daily Maximum No Action, BPJ Exceeded MONITORING REPORT(MR) VIOLATIONS for: Report Date: 08/31/22 Page 2 of 15 Permit: NCO020737 MRS Betweel 8 - 2018 and 8 - 2023 Region: % Violation Category:Limit Violation Program Category: Facility Name:% Param Nam(% County: % Subbasin:% Violation Action:% Major Minor: % PERMIT: NCO020737 FACILITY: City of Kings Mountain-Pilot Creek WWTP COUNTY: Cleveland REGION: Mooresville Limit Violation MONITORING VIOLATION UNIT OF CALCULATED % REPORT OUTFALL LOCATION PARAMETER DATE FREQUENCY MEASURE LIMIT VALUE Over VIOLATION TYPE VIOLATION ACTION 12-2018 001 Effluent Chlorine,Total Residual 12/07/18 5 X week ug/I 28 29 3.6 Daily Maximum No Action, BPJ Exceeded 01-2019 001 Effluent Chlorine,Total Residual 01/14/19 5 X week ug/I 28 31 10.7 Daily Maximum No Action, BPJ Exceeded 01-2019 001 Effluent Chlorine,Total Residual 01/16/19 5 X week ug/I 28 32 14.3 Daily Maximum No Action, BPJ Exceeded 02-2019 001 Effluent Chlorine,Total Residual 02/22/19 5 X week ug/I 28 37 32.1 Daily Maximum No Action, BPJ Exceeded 03-2019 001 Effluent Chlorine,Total Residual 03/06/19 5 X week ug/I 28 30 7.1 Daily Maximum No Action, BPJ Exceeded 04-2019 001 Effluent Chlorine,Total Residual 04/05/19 5 X week ug/I 28 42 50 Daily Maximum No Action, BPJ Exceeded 04-2019 001 Effluent Chlorine,Total Residual 04/09/19 5 X week ug/I 28 47 67.9 Daily Maximum No Action, BPJ Exceeded 05-2019 001 Effluent Chlorine,Total Residual 05/09/19 5 X week ug/I 28 39 39.3 Daily Maximum No Action, BPJ Exceeded 05-2019 001 Effluent Chlorine,Total Residual 05/14/19 5 X week ug/I 28 37 32.1 Daily Maximum No Action, BPJ Exceeded 06-2019 001 Effluent Chlorine,Total Residual 06/10/19 5 X week ug/I 28 33 17.9 Daily Maximum No Action, BPJ Exceeded 07-2019 001 Effluent Chlorine,Total Residual 07/03/19 5 X week ug/I 28 33 17.9 Daily Maximum No Action, BPJ Exceeded 10-2019 001 Effluent Chlorine,Total Residual 10/16/19 5 X week ug/I 28 33 17.9 Daily Maximum No Action, BPJ Exceeded 10-2019 001 Effluent Chlorine,Total Residual 10/21/19 5 X week ug/I 28 56 100 Daily Maximum Proceed to Exceeded Enforcement Case 10-2019 001 Effluent Chlorine,Total Residual 10/22/19 5 X week ug/I 28 83 196.4 Daily Maximum Proceed to Exceeded Enforcement Case 10-2019 001 Effluent Chlorine,Total Residual 10/23/19 5 X week ug/I 28 44 57.1 Daily Maximum No Action, BPJ Exceeded 10-2019 001 Effluent Chlorine,Total Residual 10/24/19 5 X week ug/I 28 35 25 Daily Maximum No Action, BPJ Exceeded MONITORING REPORT(MR) VIOLATIONS for: Report Date: 08/31/22 Page 15 of 15 Permit: NCO020737 MRS Betweel 8 - 2018 and 8 - 2023 Region: % Violation Category:Limit Violation Program Category: Facility Name:% Param Nam(% County: % Subbasin:% Violation Action:% Major Minor: % PERMIT: NCO020737 FACILITY: City of Kings Mountain-Pilot Creek WWTP COUNTY: Cleveland REGION: Mooresville Limit Violation MONITORING VIOLATION UNIT OF CALCULATED % REPORT OUTFALL LOCATION PARAMETER DATE FREQUENCY MEASURE LIMIT VALUE Over VIOLATION TYPE VIOLATION ACTION 07-2023 001 Effluent Chlorine,Total Residual 07/18/23 5 X week ug/I 28 48 71.4 Daily Maximum No Action, BPJ Exceeded 07-2023 001 Effluent Chlorine,Total Residual 07/19/23 5 X week ug/I 28 46 64.3 Daily Maximum No Action, BPJ Exceeded 07-2023 001 Effluent Chlorine,Total Residual 07/20/23 5 X week ug/I 28 40 42.9 Daily Maximum No Action, BPJ Exceeded 07-2023 001 Effluent Chlorine,Total Residual 07/21/23 5Xweek ug/I 28 34 21.4 Daily Maximum No Action, BPJ Exceeded 07-2023 001 Effluent Chlorine,Total Residual 07/25/23 5 X week ug/I 28 32 14.3 Daily Maximum No Action, BPJ Exceeded 07-2023 001 Effluent Chlorine,Total Residual 07/26/23 5 X week ug/I 28 30 7.1 Daily Maximum No Action, BPJ Exceeded 07-2023 001 Effluent Chlorine,Total Residual 07/27/23 5 X week ug/I 28 42 50 Daily Maximum No Action, BPJ Exceeded 07-2023 001 Effluent Chlorine,Total Residual 07/28/23 5 X week ug/I 28 47 67.9 Daily Maximum No Action, BPJ Exceeded 09-2018 001 Effluent Nitrogen,Ammonia Total(as 09/30/18 5 X week mg/I 2.6 3.58 37.7 Monthly Average Proceed to N)-Concentration Exceeded Enforcement Case 10-2019 001 Effluent Nitrogen,Ammonia Total(as 10/26/19 5 X week mg/I 7.8 9.82 25.8 Weekly Average Proceed to N)-Concentration Exceeded Enforcement Case 10-2019 001 Effluent Nitrogen,Ammonia Total(as 10/31/19 5 X week mg/I 2.6 4.27 64.2 Monthly Average Proceed to N)-Concentration Exceeded Enforcement Case 11-2019 001 Effluent Nitrogen,Ammonia Total(as 11/30/19 5 X week mg/I 8.9 10.51 18.1 Monthly Average Proceed to NOV N)-Concentration Exceeded 04-2022 001 Effluent Solids,Total Suspended- 04/09/22 5 X week mg/I 45 85.44 89.9 Weekly Average Proceed to NOV Concentration Exceeded 02-2023 001 Effluent Solids,Total Suspended- 02/18/23 5 X week mg/I 45 51.7 14.9 Weekly Average Proceed to NOV Concentration Exceeded Whole Effluent Toxicity Testing and Self Monitoring Summary Kinder Morgan Southeast Terminals LLC NCO042501/001 County: Guilford Region: WSRO Basin: CPF08 Jan Apr Jul Oct SOC JOC: Fthd24PF Begin: 4/1/2022 Acu Fthd 24hr PF Lim NonComp: 70,10: 0.0 PF: VAR IWC: 100 Freq: Q J F M A M J J A S O N D 2019 Pass - - - - - - - - - - - 2019 >100 - - - - - - - - - - - 2019 >100 - - - - - - - - - - - 2020 Pass - - - - - - - - - - - 2020 >100 - - - - - - - - - - - 2021 >100 - - - - - - - - - - - 2021 Pass - - - - - - - - - - - 2021 >100 - - - - - - - - - - - 2022 - Pass - Pass - - Pass - - Pass - - 2022 >100 - - - - - - - - - - - 2022 >100 - - - - - - - - - - - 2023 - >100 - - - - - - - - - - 2023 H Pass - Pass - - - - - - - - 2023 - >100 - - - - - - - - - - Kings Mountain,City of-Ellison WTP NCO079740/001 County: Cleveland Region: MRO Basin: BRD05 Jan Apr Jul Oct SOC JOC: Ceri7dPF Begin: 1/1/2019 Chr Monit: 3.45% NonComp: 7Q10: PF: IWC: Freq: Q J F M A M J J A S O N D 2019 Pass - - Pass - - - - Pass Pass - - 2020 Pass - - Pass - - Fail - - Pass - - 2021 Pass - - Pass - - Pass - - Pass - - 2022 Pass - - Pass - - Pass - - Pass - - 2023 Pass - - Pass - - - - - - - - Kings Mtn.-Pilot Cr.WWTP NCO020737/001 County: Cleveland Region: MRO Basin: BRD05 Jan Apr Jul Oct SOC JOC: Ceri7dPF Begin: 6/1/2015 chr lim:33% NonComp: Single 7Q10: 19.0 PF: 6.0 IWC: 33 Freq: Q J F M A M J J A S O N D 2019 Pass - - Pass - - Pass - - Pass - - 2020 Pass - - Pass - - Pass - - Pass - - 2021 Pass - - Pass - - Pass>100(P) - - Pass - - 2022 Pass - - Pass - - Pass>100(P) - - Pass >100 Pass - 2023 Pass>100 - - Pass - - - - - - - - Kinston-Regional WRF NCO024236/001 County: Lenoir Region: WARO Basin: NEU05 Jan Apr Jul Oct SOC JOC: Ceri7dPF Begin: 11/1/2018 Chr Lim:6.1 NonComp: Single 7Q10: 0 PF: 11.85 IWC: 100 Freq: Q J F M A M J J A S O N D 2019 Pass - - Pass - - Pass - - Pass - - 2020 Pass - - Pass - - Pass - - Pass - - 2021 Pass - - Pass - - Pass - - Pass - - 2022 Pass - >12(P) Pass >10(P) >12(P) Pass - >12 Pass - - 2023 Pass - - Pass - - - - - - - - Leeend: P=Fathead minnow(Pimohales oromelas).H=No Flow(facilitv is active).s=Solit test between Certified Labs Page 58 of 115 United States Environmental Protection Agency Form Approved. EPA Washington,D.C.20460 OMB No.2040-0057 Water Compliance Inspection Report 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 IN 1 2 u 3 I NCO020737 111 121 22/03/22 I17 18 LC]I 19 I G I 201 I 21111I I I I I I I II I I I I I I I I I I I I I I I I I I I I I I I II I I I I I r6 Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA ----------------------Reserved------------------- 67 1.0 70L 711„ I 72 73 LJ74 79 I I I I 80 Section B: Facility Data Name and Location of Facility Inspected(For Industrial Users discharging to POTW,also include Entry Time/Date Permit Effective Date POTW name and NPDES permit Number) 09:50AM 22/03/22 20/02/01 Pilot Creek WWTP 200 Potts Creek Rd Exit Time/Date Permit Expiration Date Kings Mountain NC 28086 12:30PM 22/03/22 23/08/31 Name(s)of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s) Other Facility Data Kendrene Richelle Putnam/ORC/704-739-7131/ Name,Address of Responsible Official/Title/Phone and Fax Number Contacted Richelle Meek,PO Box 429 Kings Mtn NC 280860429/ORC/704-739-7131/ No Section C:Areas Evaluated During Inspection (Check only those areas evaluated) Permit 0 Flow Measurement Operations&Maintenar Records/Reports Self-Monitoring Progran 0 Sludge Handling Dispo: Facility Site Review Effluent/Receiving Wate 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 Michael J Meilinger DWR/MRO WQ/704-235-2183/ Ori A Tuvia DWR/MRO WQ/704-663-1699/ Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date W. Corey Basinger DWR/Division of Water Quality/704-235-2194/ EPA Form 3560-3(Rev 9-94)Previous editions are obsolete. Page# 1 NPDES yr/mo/day Inspection Type 1 31 NCO020737 I11 12I 22/03/22 117 18 i c i Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) Page# 2 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 03/22/2022 Inspection Type: 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? ■ ❑ ❑ ❑ Comment: New tiered permit was issued and became effective on 2/1/2020. The new permit has removed the Arsenic limit for the tiers under 6 MGD. The City implements an approved Industrial Pretreatment Program. 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? ❑ ❑ ❑ ■ Page# 3 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 03/22/2022 Inspection Type: Compliance Evaluation Record Keeping Yes No NA NE Comment: The records reviewed durinq the inspection were organized and well maintained. DMRs, COCs, ORC visitation log, Bench sheets, and calibration logs were reviewed for the period October 2021 through December 2021. Chlorine curve was late to be renewed for the year of 2021 and the new chlorine curve did not pass the low chlorine limit (10 ug/L)the higher level passed 50 ug/L, is too high since the permit limit is 28 ug/L. Laboratory Yes No NA NE Are field parameters performed by certified personnel or laboratory? ■ ❑ ❑ ❑ Are all other parameters(excluding field parameters) performed by a certified lab? 0 ❑ ❑ ❑ # Is the facility using a contract lab? 0 ❑ ❑ ❑ # 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? ❑ ❑ ❑ ■ Comment: Influent and effluent analyses are performed under the City's certified laboratory#222. Pace Labs (metals, priority pollutants, total phosphorus, total nitrogen, oil & grease, Thallium), and ETT, Inc.(toxicity) have also been contracted to provide analytical support Influent Sampling Yes No NA NE # Is composite sampling flow proportional? 0 ❑ ❑ ❑ Is sample collected above side streams? 0 ❑ ❑ ❑ Is proper volume collected? ■ ❑ ❑ ❑ Is the tubing clean? ■ ❑ ❑ ❑ # Is proper temperature set for sample storage (kept at less than or equal to 6.0 0 ❑ ❑ ❑ degrees Celsius)? Is sampling performed according to the permit? 0 ❑ ❑ ❑ Comment: The subject permit requires influent composite BOD and TSS samples. The facility staff perform and document monthly aliquot verifications. Influent PH levels are continuously monitored by an in-line monitoring system. Effluent Sampling Yes No NA NE Is composite sampling flow proportional? 0 ❑ ❑ ❑ Is sample collected below all treatment units? 0 ❑ ❑ ❑ Is proper volume collected? 0 ❑ ❑ ❑ Is the tubing clean? 0 ❑ ❑ ❑ # Is proper temperature set for sample storage (kept at less than or equal to 6.0 0 ❑ ❑ ❑ degrees Celsius)? Page# 4 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 03/22/2022 Inspection Type: Compliance Evaluation Effluent Sampling Yes No NA NE Is the facility sampling performed as required by the permit (frequency, sampling type ❑ ❑ ❑ representative)? Comment: The subject permit requires composite and grab effluent samples. The facility staff perform and document monthly aliquot verifications. Samples taken are time proportional. Upstream / Downstream Sampling Yes No NA NE Is the facility sampling performed as required by the permit (frequency, sampling type, ■ ❑ ❑ ❑ and sampling location)? Comment: Operations & Maintenance Yes No NA NE Is the plant generally clean with acceptable housekeeping? 0 ❑ ❑ ❑ Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable 0 ❑ ❑ ❑ Solids, pH, DO, Sludge Judge, and other that are applicable? Comment: The facility staff incorporate a comprehensive process control program with all measurements being properly documented and maintained on-site. Overall the waste treatment unit is continually improving. The facility has purchased a SCADA system and is in the process of improving it, the facility has a done good lob reducing the dead spot areas in the aeration basins, and in addition greatly improved the condition of the clarifiers. However, the following items need to be adressed: 1. At the time of the inspection it was observed that the clarifier#3 weir was uneven. 2. Chlorine curve was late to be renewed for the year of 2021 and the new chlorine curve did not pass the low chlorine limit (10 ug/L)the higher level passed 50 ug/L, is above the permit limit 28 ug/L Pump Station - Influent Yes No NA NE Is the pump wet well free of bypass lines or structures? 0 ❑ ❑ ❑ Is the wet well free of excessive grease? 0 ❑ ❑ ❑ Are all pumps present? 0 ❑ ❑ ❑ Are all pumps operable? 0 ❑ ❑ ❑ Are float controls operable? 0 ❑ ❑ ❑ Is SCADA telemetry available and operational? 0 ❑ ❑ ❑ Is audible and visual alarm available and operational? ❑ ❑ ❑ Comment: Both screw pumps were operational and in service. Bar Screens Yes No NA NE Type of bar screen Page# 5 Permit: NC0020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 03/22/2022 Inspection Type: Compliance Evaluation Bar Screens Yes No NA NE a.Manual ❑ b.Mechanical Are the bars adequately screening debris? 0 ❑ ❑ ❑ Is the screen free of excessive debris? 0 ❑ ❑ ❑ Is disposal of screening in compliance? 0 ❑ ❑ ❑ Is the unit in good condition? ❑ ❑ ❑ Comment: Screenings are disposed at the Cleveland County Landfill. Flow Measurement - Influent Yes No NA NE # Is flow meter used for reporting? 0 ❑ ❑ ❑ Is flow meter calibrated annually? 0 ❑ ❑ ❑ Is the flow meter operational? 0 ❑ ❑ ❑ (If units are separated) Does the chart recorder match the flow meter? ❑ ❑ ❑ Comment: The influent flow meter is calibrated annually. Chemical Feed Yes No NA NE Is containment adequate? 0 ❑ ❑ ❑ Is storage adequate? ■ ❑ ❑ ❑ Are backup pumps available? ■ ❑ ❑ ❑ Is the site free of excessive leaking? 0 ❑ ❑ ❑ Comment: Secondary Clarifier Yes No NA NE Is the clarifier free of black and odorous wastewater? 0 ❑ ❑ ❑ Is the site free of excessive buildup of solids in center well of circular clarifier? 0 ❑ ❑ ❑ Are weirs level? 0 ❑ ❑ ❑ Is the site free of weir blockage? ■ ❑ ❑ ❑ Is the site free of evidence of short-circuiting? 0 ❑ ❑ ❑ Is scum removal adequate? 0 ❑ ❑ ❑ Is the site free of excessive floating sludge? 0 ❑ ❑ ❑ Is the drive unit operational? 0 ❑ ❑ ❑ Is the return rate acceptable (low turbulence)? 0 ❑ ❑ ❑ Is the overflow clear of excessive solids/pin floc? 0 ❑ ❑ ❑ Page# 6 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 03/22/2022 Inspection Type: Compliance Evaluation Secondary Clarifier Yes No NA NE Is the sludge blanket level acceptable? (Approximately '/4 of the sidewall depth) 0 ❑ ❑ ❑ Comment: 3 (1,3,4) clarifiers were in service. At the time of the inspection it was observed that the clarifier#3 weir was uneven. Pumps-RAS-WAS Yes No NA NE Are pumps in place? ■ ❑ ❑ ❑ Are pumps operational? 0 ❑ ❑ ❑ Are there adequate spare parts and supplies on site? ❑ ❑ 0 ❑ Comment: Disinfection-Gas Yes No NA NE Are cylinders secured adequately? 0 ❑ ❑ ❑ Are cylinders protected from direct sunlight? 0 ❑ ❑ ❑ Is there adequate reserve supply of disinfectant? ■ ❑ ❑ ❑ Is the level of chlorine residual acceptable? 0 ❑ ❑ ❑ Is the contact chamber free of growth, or sludge buildup? 0 ❑ ❑ ❑ Is there chlorine residual prior to de-chlorination? 0 ❑ ❑ ❑ Does the Stationary Source have more than 2500 Ibs of Chlorine (CAS No. 0 ❑ ❑ ❑ 7782-50-5)? If yes, then is there a Risk Management Plan on site? 0 ❑ ❑ ❑ If yes, then what is the EPA twelve digit ID Number? (1000- - ) If yes, then when was the RMP last updated? Comment: De-chlorination Yes No NA NE Type of system ? Gas 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? ❑ ❑ 0 ❑ Comment: Are the tablets the proper size and type? ❑ ❑ ■ ❑ Are tablet de-chlorinators operational? ❑ ❑ 0 ❑ Number of tubes in use? Page# 7 Permit: NC0020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 03/22/2022 Inspection Type: Compliance Evaluation De-chlorination Yes No NA NE Comment: Flow Measurement - Effluent Yes No NA NE # Is flow meter used for reporting? 0 ❑ ❑ ❑ Is flow meter calibrated annually? 0 ❑ ❑ ❑ Is the flow meter operational? 0 ❑ ❑ ❑ (If units are separated) Does the chart recorder match the flow meter? 0 ❑ ❑ ❑ Comment: The flow meters (end of each chlorine contact chamber) are calibrated annually Effluent Pipe Yes No NA NE Is right of way to the outfall properly maintained? ❑ ❑ ❑ Are the receiving water free of foam other than trace amounts and other debris? ❑ ❑ ❑ ■ If effluent (diffuser pipes are required) are they operating properly? ❑ ❑ ❑ Comment: Did not examine the outfall Aerobic Digester Yes No NA NE Is the capacity adequate? 0 ❑ ❑ ❑ Is the mixing adequate? 0 ❑ ❑ ❑ Is the site free of excessive foaming in the tank? ■ ❑ ❑ ❑ # Is the odor acceptable? ■ ❑ ❑ ❑ # Is tankage available for properly waste sludge? 0 ❑ ❑ ❑ Comment: Solids Handling Equipment Yes No NA NE Is the equipment operational? 0 ❑ ❑ ❑ Is the chemical feed equipment operational? 0 ❑ ❑ ❑ Is storage adequate? ❑ ❑ 0 ❑ Is the site free of high level of solids in filtrate from filter presses or vacuum filters? 0 ❑ ❑ ❑ Is the site free of sludge buildup on belts and/or rollers of filter press? 0 ❑ ❑ ❑ Is the site free of excessive moisture in belt filter press sludge cake? 0 ❑ ❑ ❑ The facility has an approved sludge management plan? ❑ ❑ ❑ Comment: Belt press appeared to be running properly at the time of the inspection Page# 8 Permit: NC0020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 03/22/2022 Inspection Type: Compliance Evaluation Standby Power Yes No NA NE Is automatically activated standby power available? 0 ❑ ❑ ❑ Is the generator tested by interrupting primary power source? 0 ❑ ❑ ❑ Is the generator tested under load? 0 ❑ ❑ ❑ Was generator tested & operational during the inspection? ❑ ❑ ❑ Do the generator(s) have adequate capacity to operate the entire wastewater site? 0 ❑ ❑ ❑ Is there an emergency agreement with a fuel vendor for extended run on back-up 0 ❑ ❑ ❑ power? Is the generator fuel level monitored? ❑ ❑ ❑ Comment: The facility is equipped with two backup generators. The smaller generator powers the blowers for aeration basin #3 and the larger generator powers the rest of the plant. Page# 9 NCO020737 Pilot Creek WWTP 8/31/2023 BOD monthly removal rate TSS monthly removal rate Month RR(%) Month RR(%) Month RR(%) Month RR(%) February-19 97.90 August-21 97.87 February-19 95.57 August-21 96.35 March-19 98.28 September-21 98.25 March-19 96.41 September-21 96.70 April-19 98.34 October-21 97.98 April-19 96.92 October-21 96.50 May-19 98.20 November-21 97.13 May-19 96.44 November-21 96.09 June-19 97.83 December-21 97.75 June-19 96.90 December-21 96.09 July-19 98.26 January-22 98.05 July-19 97.39 January-22 94.37 August-19 98.39 February-22 98.20 August-19 97.73 February-22 94.04 September-19 98.31 March-22 98.54 September-19 97.60 March-22 95.90 October-19 96.63 April-22 98.22 October-19 96.02 April-22 86.42 November-19 96.26 May-22 96.92 November-19 95.48 May-22 96.96 December-19 97.31 June-22 97.73 December-19 95.48 June-22 96.46 January-20 97.88 July-22 98.20 January-20 94.60 July-22 97.10 February-20 96.04 August-22 98.03 February-20 93.37 August-22 96.40 March-20 97.27 September-22 98.74 March-20 94.22 September-22 97.48 April-20 97.96 October-22 98.86 April-20 91.49 October-22 97.35 May-20 96.88 November-22 98.34 May-20 92.00 November-22 96.74 June-20 97.79 December-22 98.26 June-20 95.69 December-22 95.04 July-20 97.69 January-23 98.29 July-20 96.97 January-23 94.58 August-20 97.69 February-23 97.99 August-20 97.94 February-23 89.17 September-20 98.41 March-23 99.36 September-20 97.94 March-23 90.50 October-20 97.90 April-23 98.13 October-20 97.38 April-23 92.96 November-20 98.13 May-23 98.12 November-20 96.05 May-23 96.61 December-20 97.56 June-23 98.19 December-20 95.39 June-23 94.78 January-21 98.23 July-23 January-21 96.01 July-23 February-21 97.59 August-23 February-21 94.27 August-23 March-21 97.05 September-23 March-21 93.28 September-23 April-21 98.08 October-23 April-21 96.18 October-23 May-21 97.47 November-23 May-21 96.06 November-23 June-21 97.98 December-23 June-21 96.31 December-23 July-21 97.89 January-24 July-21 95.35 January-24 Overall BOD removal rate 97.89 Overall TSS removal rate 95.43 United States Environmental Protection Agency Form Approved. EPA Washington,D.C.20460 OMB No.2040-0057 Water Compliance Inspection Report 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 IN 1 2 u 3 I NCO020737 I11 121 23/10/26 I17 18I� I 19 I G I 201 I 211IIIII 111111III II III III1 I I IIIII IIIIIIIII II r6 Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA ----------------------Reserved------------------- 67 70LJ 71 [L I 72 L-] 73 1 74 79 I I I I 80 Section B: Facility Data Name and Location of Facility Inspected(For Industrial Users discharging to POTW,also include Entry Time/Date Permit Effective Date POTW name and NPDES permit Number) 09:25AM 23/10/26 20/02/01 Pilot Creek WWTP 200 Potts Creek Rd Exit Time/Date Permit Expiration Date Kings Mountain NC 28086 03:OOPM 23/10/26 23/08/31 Name(s)of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s) Other Facility Data Rickey Lee Bailey/ORC/704-739-7131/ Name,Address of Responsible Official/Title/Phone and Fax Number Contacted Ricky Duncan,PO Box 429 Kings Mtn NC 280860429//704-734-4525/7047302152 No Section C:Areas Evaluated During Inspection (Check only those areas evaluated) Permit 0 Flow Measurement Operations&Maintenar Records/Reports Self-Monitoring Progran 0 Sludge Handling Dispo: Facility Site Review Effluent/Receiving Wate 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 Wes Bell DWR/MRO WQ/704-235-2192/ Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date Andrew Pitner DWR/MRO WQ/704-663-1699 Ext.2180/ EPA Form 3560-3(Rev 9-94)Previous editions are obsolete. Page# 1 NPDES yr/mo/day Inspection Type (Cont.) 1 31 NCO020737 I11 12I 23/10/26 117 18 i c i Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) On-site Representatives: The following City staff were in attendance during the inspection: Mr. Donnie Spencer, Mr. Lee Bailey and Mr. Kevin Hodges. Record Keeping Section cont'd: Several eDMRs will be revised and resubmitted to correct transcription errors in the following months: - October 2022 (correct units of measurement for influent selenium and thallium); -April 2023 [correct units of measurement for effluent selenium, thallium, and oil & grease (and influent), zinc (and influent), correct">" symbol to "<" for influent oil &grease, and remove one effluent mercury value— 11th or 13th]; - May 2023 (correct units of measurement for effluent thallium); - July 2023 [add effluent tox value and correct units of measurement for effluent arsenic (and result) and cyanide]. Effluent temperature values should also be added on all eDMRs starting in May 2023. The facility staff must ensure all units of measurement, sample types, etc. are correctly reported on all future eDMRs. Page# 2 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 10/26/2023 Inspection Type: 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? ■ ❑ ❑ ❑ Comment: The Division received the City's permit renewal package on 3/7/2023. The City implements a Division-approved Industrial Pretreatment Program. The last compliance evaluation inspection at this facility was performed by DWR staff on 3/22/2022. 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? ■ ❑ ❑ ❑ Page# 3 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 10/26/2023 Inspection Type: Compliance Evaluation Record Keeping Yes No NA NE Comment: The records reviewed durinq the inspection were organized and well maintained. Discharge Monitoring Reports (eDMRs)were reviewed for the period September 2022 through August 2023. A weekly average TSS effluent violation was reported in February 2023. The Division has previously addressed this limit violation through the issuance of a Notice of Violation (NOV). See Summary Section for additional comments. Laboratory Yes No NA NE Are field parameters performed by certified personnel or laboratory? ■ ❑ ❑ ❑ Are all other parameters(excluding field parameters) performed by a certified lab? 0 ❑ ❑ ❑ # Is the facility using a contract lab? 0 ❑ ❑ ❑ # 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? ❑ ❑ ❑ ■ Comment: Influent and effluent analyses (including filed) are performed under the City's laboratory certification #222. Meritech, Inc. has also been contracted to provide analytical support. The 10.0 S.U. pH buffer had expired and should be discarded. The lab has an additional 10.0 S.U. standard (not expired) that can be used for all future pH meter calibrations. Influent Sampling Yes No NA NE # Is composite sampling flow proportional? ❑ 0 ❑ ❑ Is sample collected above side streams? ❑ 0 ❑ ❑ Is proper volume collected? ■ ❑ ❑ ❑ Is the tubing clean? ■ ❑ ❑ ❑ # Is proper temperature set for sample storage (kept at less than or equal to 6.0 0 ❑ ❑ ❑ degrees Celsius)? Is sampling performed according to the permit? ❑ 0 ❑ ❑ Comment: The subject permit requires influent composite BOD and TSS samples. The facility staff were collecting time-based (constant time/constant volume) composite influent samples. Please be advised that flow proportional influent composite samples must be collected as required by the by the subject Permit (Part ll, Section A. Composite Sample). The Division may grant a variance to collect time-based composite samples only if the daily flow rates do not vary by more than 15%. A variance request has not been submitted and/or received by the Division. Effluent Sampling Yes No NA NE Is composite sampling flow proportional? ❑ 0 ❑ ❑ Is sample collected below all treatment units? 0 ❑ ❑ ❑ Page# 4 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 10/26/2023 Inspection Type: Compliance Evaluation Effluent Sampling Yes No NA NE Is proper volume collected? 0 ❑ ❑ ❑ Is the tubing clean? ■ ❑ ❑ ❑ # Is proper temperature set for sample storage (kept at less than or equal to 6.0 0 ❑ ❑ ❑ degrees Celsius)? Is the facility sampling performed as required by the permit (frequency, sampling type ❑ ❑ ❑ representative)? Comment: The subject permit requires composite and grab effluent samples. The facility staff were collecting time-based (constant time/constant volume) composite effluent samples. Please be advised that flow proportional effluent composite samples must be collected as required by the by the subject Permit (Part II, Section A. Composite Sample). The Division may grant a variance to collect time-based composite samples only if the daily flow rates do not vary by more than 15%. A variance request has not been submitted and/or received by the Division. In addition, facility staff had used the values from the in-line dissolved oxygen (DO) monitoring system (continuous) to report the daily DO effluent values on the May and June 2023 eDMRs instead of using a calibrated hand held meter. Please be advised that daily grab samples must be collected and analyzed as required by the subject Permit (Part I, A(1) Effluent Limitations & Monitoring Requirements). Upstream / Downstream Sampling Yes No NA NE Is the facility sampling performed as required by the permit (frequency, sampling type, 0 ❑ ❑ ❑ and sampling location)? Comment: Operations & Maintenance Yes No NA NE Is the plant generally clean with acceptable housekeeping? 0 ❑ ❑ ❑ Does the facility analyze process control parameters, for ex: MLSS, MCRT, Settleable ❑ ❑ ❑ Solids, pH, DO, Sludge Judge, and other that are applicable? Comment: The wastewater treatment facility appeared to be adequately treating wastewater at the time of the inspection. Process control measurements were being performed with the documentation being maintained on-site. The facility is equipped with a SCADA system and the wastewater treatment plant is visited seven days per week with staff on call for any alarm/emergency conditions. Pump Station - Influent Yes No NA NE Is the pump wet well free of bypass lines or structures? 0 ❑ ❑ ❑ Is the wet well free of excessive grease? 0 ❑ ❑ ❑ Are all pumps present? 0 ❑ ❑ ❑ Are all pumps operable? 0 ❑ ❑ ❑ Are float controls operable? 0 ❑ ❑ ❑ Page# 5 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 10/26/2023 Inspection Type: Compliance Evaluation Pump Station - Influent Yes No NA NE Is SCADA telemetry available and operational? 0 ❑ ❑ ❑ Is audible and visual alarm available and operational? ❑ ❑ 0 ❑ Comment: The telemetry type alarm system properly operated during the on-site test on the high water alarm. Bar Screens Yes No NA NE Type of bar screen a.Manual ❑ b.Mechanical Are the bars adequately screening debris? 0 ❑ ❑ ❑ Is the screen free of excessive debris? ■ ❑ ❑ ❑ Is disposal of screening in compliance? 0 ❑ ❑ ❑ Is the unit in good condition? ❑ ❑ ❑ Comment: Screenings are disposed at a permitted landfill. Chemical Feed Yes No NA NE Is containment adequate? 0 ❑ ❑ ❑ Is storage adequate? ■ ❑ ❑ ❑ Are backup pumps available? ■ ❑ ❑ ❑ Is the site free of excessive leaking? ■ ❑ ❑ ❑ Comment: Sodium hydroxide is added to the influent (prior to aeration basins) to maintain appropriate alkalinity/pH levels. Aeration Basins Yes No NA NE Mode of operation Ext. Air Type of aeration system Diffused Is the basin free of dead spots? ❑ 0 ❑ ❑ Are surface aerators and mixers operational? ❑ ❑ ■ ❑ Are the diffusers operational? 0 ❑ ❑ ❑ Is the foam the proper color for the treatment process? 0 ❑ ❑ ❑ Does the foam cover less than 25% of the basin's surface? 0 ❑ ❑ ❑ Is the DO level acceptable? 0 ❑ ❑ ❑ Is the DO level acceptable?(1.0 to 3.0 mg/1) 0 ❑ ❑ ❑ Page# 6 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 10/26/2023 Inspection Type: Compliance Evaluation Aeration Basins Yes No NA NE Comment: All three aeration basins were operational and in service. Wastewater staff have initiated adjustments to the influent flow and air distribution sysems within the aeration basins due to operational issues associated with the blowers. Dead spots were observed due to the lack of proper aeration/mixing. The City has purchased three new blowers with the first blower to be received on-site by December 2023. Secondary Clarifier Yes No NA NE Is the clarifier free of black and odorous wastewater? 0 ❑ ❑ ❑ Is the site free of excessive buildup of solids in center well of circular clarifier? 0 ❑ ❑ ❑ Are weirs level? ❑ 0 ❑ ❑ Is the site free of weir blockage? 0 ❑ ❑ ❑ Is the site free of evidence of short-circuiting? ■ ❑ ❑ ❑ Is scum removal adequate? 0 ❑ ❑ ❑ Is the site free of excessive floating sludge? 0 ❑ ❑ ❑ Is the drive unit operational? 0 ❑ ❑ ❑ Is the return rate acceptable (low turbulence)? 0 ❑ ❑ ❑ Is the overflow clear of excessive solids/pin floc? 0 ❑ ❑ ❑ Is the sludge blanket level acceptable? (Approximately '/4 of the sidewall depth) 0 ❑ ❑ ❑ Comment: All three secondary clarifiers (1,3,4)were operational and in service. Note: Afourth clarifier was taken out of service several years ago. The weirs for clarifier#3 were unlevel; however, no evidence of short-circuiting was observed. Plans should be made to level the weirs in the tuture. The sludge blanket level in clarifier#4 was greater than a quarter of the sidewall depth; however, wastewater staff have been wasting and reducing the MLSS level in aeration basin #4. Pumps-RAS-WAS Yes No NA NE Are pumps in place? 0 ❑ ❑ ❑ Are pumps operational? ■ ❑ ❑ ❑ Are there adequate spare parts and supplies on site? ❑ ❑ ❑ ■ Comment: Disinfection-Gas Yes No NA NE Are cylinders secured adequately? ■ ❑ ❑ ❑ Are cylinders protected from direct sunlight? 0 ❑ ❑ ❑ Is there adequate reserve supply of disinfectant? 0 ❑ ❑ ❑ Is the level of chlorine residual acceptable? 0 ❑ ❑ ❑ Is the contact chamber free of growth, or sludge buildup? ■ ❑ ❑ ❑ Page# 7 Permit: NCO020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 10/26/2023 Inspection Type: Compliance Evaluation Disinfection-Gas Yes No NA NE Is there chlorine residual prior to de-chlorination? 0 ❑ ❑ ❑ Does the Stationary Source have more than 2500 Ibs of Chlorine (CAS No. ❑ ❑ ❑ 7782-50-5)? If yes, then is there a Risk Management Plan on site? ❑ ❑ ❑ If yes, then what is the EPA twelve digit ID Number? (1000- - ) If yes, then when was the RMP last updated? Comment: Flow Measurement - Effluent Yes No NA NE # Is flow meter used for reporting? 0 ❑ ❑ ❑ Is flow meter calibrated annually? 0 ❑ ❑ ❑ Is the flow meter operational? 0 ❑ ❑ ❑ (If units are separated) Does the chart recorder match the flow meter? ❑ ❑ ❑ Comment: The facility is equipped with a flow meter(and V-notch weir) at the outlets of the three chlorine contact chambers. All flows from the three flow meters are totalized (automated system) and reported on the eDMRs. All flow meters are calibrated annually (at a minimum) and were last calibrated on 3/8/2023 by Laboratory Instrument Services, LLC. The ORC and staff must ensrue the contracted company that performs the calibrations provides all calibration data including instantaneous confirmation measurements. De-chlorination Yes No NA NE Type of system ? Gas Is the feed ratio proportional to chlorine amount (1 to 1)? 0 ❑ ❑ ❑ Is storage appropriate for cylinders? ■ ❑ ❑ ❑ # Is de-chlorination substance stored away from chlorine containers? 0 ❑ ❑ ❑ Comment: Are the tablets the proper size and type? ❑ ❑ 0 ❑ Are tablet de-chlorinators operational? ❑ ❑ ■ ❑ Number of tubes in use? Comment: Effluent Pipe Yes No NA NE Is right of way to the outfall properly maintained? ❑ ❑ ❑ Are the receiving water free of foam other than trace amounts and other debris? ❑ ❑ ❑ If effluent (diffuser pipes are required) are they operating properly? ❑ ❑ 0 ❑ Page# 8 Permit: NC0020737 Owner-Facility: Pilot Creek WWTP Inspection Date: 10/26/2023 Inspection Type: Compliance Evaluation Effluent Pipe Yes No NA NE Comment: The effluent appeared clear with no floatable solids or foam. Aerobic Digester Yes No NA NE Is the capacity adequate? 0 ❑ ❑ ❑ Is the mixing adequate? 0 ❑ ❑ ❑ Is the site free of excessive foaming in the tank? ■ ❑ ❑ ❑ # Is the odor acceptable? ■ ❑ ❑ ❑ # Is tankage available for properly waste sludge? ❑ ❑ ❑ Comment: Both aerobic digesters were operational and in service. Solids Handling Equipment Yes No NA NE Is the equipment operational? 0 ❑ ❑ ❑ Is the chemical feed equipment operational? 0 ❑ ❑ ❑ Is storage adequate? ■ ❑ ❑ ❑ Is the site free of high level of solids in filtrate from filter presses or vacuum filters? ❑ ❑ ❑ Is the site free of sludge buildup on belts and/or rollers of filter press? ❑ ❑ ❑ Is the site free of excessive moisture in belt filter press sludge cake? ❑ ❑ ❑ The facility has an approved sludge management plan? 0 ❑ ❑ ❑ Comment: The belt press was operation; however, the unit was not in service at the time of the inspection. Dewatered bio-solids are transported and disposed at a permitted landfill by City staff. Standby Power Yes No NA NE Is automatically activated standby power available? 0 ❑ ❑ ❑ Is the generator tested by interrupting primary power source? 0 ❑ ❑ ❑ Is the generator tested under load? 0 ❑ ❑ ❑ Was generator tested & operational during the inspection? 0 ❑ ❑ ❑ 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 0 ❑ ❑ ❑ power? Is the generator fuel level monitored? ❑ ❑ ❑ Comment: The facility is equipped with two generators (1 —aeration basin #3 blowers and 1 — rest of WWTP) that are serviced twice per year by Carolina Power Solutions. Page# 9 mlvs KINGS MOUNTAIN NORTH CAROLINA htt&zg.aevated. Nick Coco, PE(he/him/his) Engineer/I/ NPDES Municipal Permitting Unit NC DEQ/Division of Water Resources/Water Quality Permitting Nick, Please see the following information regarding your request for: Brief narrative of treatment process(attached) Sludge Management Plan (attached) Waiver for 24 hour staffing at Pilot Creek Pilot Creek WWTP has implemented a comprehensive SCADA Monitoring System known as VSCADA. Alarms generated are continuously routed to a stand-by phone and also to a supervisor phone.The alarms generated include the following: Power outage, diesel generator start, Inf.screw pump off, Blowers(2 per basin)off, Inf. PH low, Inf.flow low/high, Eff. PH low,C12 and S02 bldg. detector alarms. Other SCADA readings on screen which can be accessed remotely via cell phone include: Inf. Flow/PH, Eff. Flow/PH/DO, Inf. Flow/PH, Flow from each CL2 contact chamber and Cl2 PPD feed for each, Eff.S02 feed rate in PPD,Sludge digester#1 and#2 level in feet.Also,we can remotely monitor 4 main pump stations for PH (McGill, Hwy.74, Long Branch and Beason Creek). Again all of these parameters can be accessed remotely via City cell phone.The Collections Dept. has this capability for all 42 pump stations operated by the City and also has remote monitoring and alarms to a City Standby cell. Visitation schedule is 365 days per year with the ORC and/or back-up ORC visiting the WWTP Mon.thru Fri. and a certified operator is on-site for weekends and holidays. Rounds are completed 365 days per year and all operating equipment is checked daily.Additional personnel are available for unforeseen/major issues that may arise. Thanks for your kind consideration. Sincerely, Lee Bailey,COKM WWTP ORC Pilot Creek NCO020737 Kevin Hodges,COKM WWTP Back-up ORC Pilot Creek NCO020737 City of Kings Mountain I City Hall 1 101 W Gold St. Kings Mountain,NC 28086 Phone:704-734-0333 1 info@cityofkm.com www.cityofkm.com TO SLUDGE DISPOSAL MANAGEMENT PLAN PILOT CREEK WASTEWATER TREATMENT FACILITY Wastewater Treatment Facility The Wastewater Treatment Facility (Picot Creek W W7P), operated by the City of zings wMountain, is an extended aeration activateds(udge facility. The treatment facility is located at 200 Potts Creek Road, .zings .Mountain, NC and services the city andsurroundng areas. The waste activateds(udge is pumped from secondary clarifiers to one of two aerobic holding tanks. The waste concentration ranges from 2°o to 3°0 TotaCSuspendedSolids. 7'he sludge is then aerated andpH adjusted as needed: The solids are pumped to a 2.2 meter BeCt Filter Press for further dewatering to a cake of 15°o to 18% TotaCSolids. The facility produces approximately Boo dry tons per year which is transported to the Cleveland County landfi((for finaCdisposaC. Disposal Facility Information Cleve land County l andfi(( (Se(f.McNe illy l andfiCO 250 FieCdtng Road Cherryvi((e, NC 28021 Contact Person: -Air. Sam -'Al. lockridge Phone Number: 704-484-5100 lhf�Cd#4 aw*%,mid opmteath,e waak"ctten, hfahnent VWAx4 known as Pda Greek WaatewOWU `the pi.tet cheek,W+ AP t&WC ted,@*tG hi,gh,way,74 69pmw P"OmCka Yl.PVf-G Pmvtit# f'L00020737 a,Uow&th.e,WAU%to,bf, MAUWdgd bcythe,State,C+hsnth,CaMA"a,t&di4cluVW the;heated qbLumtte,Buytale-Cheek,. Pwceaa P(W,cryeek ww#p,is pvmutted den,3.0 million,"Uovta a dcuj,ftga). the,vw-i,utay ep"O"at a"""50% capacit%4*�(MW- ) �z.a 7� I'm 4e WAentenathe,tvxdmO&VWAALYthloug.h,th,,netwerik,C+Couectiow "4t M Unea and,Litt 4tat 41&Which,ab"MMXM,ent u "WKWitty caw e.nce,aga.iw allGW tenrth.e,4CWVU VOW. 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