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HomeMy WebLinkAboutNC0026051_Draft Permit_20060608Michael F. Easley, Governor June 7, 2006 8 200&JIH Subject: Dear Mr. Hill: > An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper Mr. Chuck Hill, Utility Division Manager Durham County 120 Parrish Street, Suite 110 Durham, North Carolina 27701 North Carolina Division of Water Quality Internet: h2o.enr.state.nc.us 1617 Mail Service Center 512 N. Salisbury St. Raleigh, NC 27699-1617 Raleigh, NC 27604 William G. Ross Jr., Secretary North Carolina Department of Environment and Natural Resources Alan W. Klimek, P.E. Director Division of Water Quality Draft NPDES Permit Permit NC0026051 Durham County Triangle WWTP Durham County Enclosed with this letter is a copy of the draft permit for your facility. Please review the draft carefully to ensure thorough understanding of the conditions and requirements it contains. J H North Carolina----------------------------Naturally Phone (919) 733-5083 Customer Service FAX (919)733-0719 1-877-623-6748 Please submit any comments to me no later than thirty days following your receipt of the draft. Comments should be sent to the address listed at the bottom of this page. If no adverse comments are received from the public or from you, this permit will likely be issued in September with an effective date of October 1, 2006. o/111 I Ira The draft permit contains the following significant changes from your current permit: The 6.0 MGD effluent page has been removed since the plant has been expanded to 12.0 MGD. The chloride limit has been removed and the monitoring frequency reduced since an analysis of recent data indicates no reasonable potential to exceed water quality standards. > A weekly average limit of 1800 pg/L for fluoride was added to the permit. Data for fluoride showed reasonable potential to exceed the water quality standard. The limit may be reduced or deleted in the future upon written notification of the Division, if the permittee provides updated effluent data (recommended one year period) that shows no reasonable potential to exceed the water quality standard. > A requirement to perform an effluent pollutant scan has been added. > For the 2006 permit renewal cycle the Division developed a permitting strategy to address nutrient concerns in the Cape Fear River Basin. This strategy is being applied at permit renewal to existing discharges on the basin. The strategy calls for additional nutrient monitoring and reporting to support the efforts of the Modeling and TMDL Unit in developing special studies and TMDL projects. Dischargers in the Jordan Lake watershed will monitor TN and TP 3 times per week, report nitrogen species, and report TN and TP as both concentration and mass loads. The permit also includes a re-opener special condition. In the event that the Environmental Management Commission adopts a nutrient management strategy or the EPA approves a TMDL in the coming permit term, the condition allows the Division to re-open affected permits to set nutrient limits and related conditions accordingly. 1 • t If you have any questions or comments concerning this draft permit, contact me at (919) 733-5083. cc: Durham County Triangle WWTP Page 2 NPDES Unit Raleigh Regional Office / Surface Water Protection Section Raleigh Regional Office / DEH EPA Region 4 Aquatic Toxicology Unit Sincerely, Teresa Rodriguez Eastern NPDES Program ! Permit NC0026051 PERMIT TO DISCHARGE WASTEWATER UNDER THE NATIONAL POLLUTANT DISCHARGE ELIMINATION SYSTEM Durham County is hereby authorized to discharge wastewater from a facility located at the The permit shall become effective This permit and the authorization to discharge shall expire at midnight on April 30, 2011. Signed this day DRAFT STATE OF NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES DIVISION OF WATER QUALITY In compliance with the provisions of North Carolina General Statute 143-215.1, other lawful standards and regulations promulgated and adopted by the North Carolina Environmental Management Commission, and the Federal Water Pollution Control Act, as amended, to receiving waters designated as Northeast Creek in the Cape Fear River Basin in accordance with effluent limitations, monitoring requirements, and other conditions set forth in Parts I, II, III, and IV hereof. Alan W. Klimek, P.E., Director Division of Water Quality By Authority of the Environmental Management Commission Durham County Triangle WWTP 5926 NC Highway 55 Durham County Permit NC0026051 SUPPLEMENT TO PERMIT COVER SHEET Durham County is hereby authorized to: Mechanical bar screen ■ Mechanical grit removal Parshall flume ■ Influent pump station ■ Three 5-stage BNR trains ■ Four secondary clarifiers ■ Five tertiary sand filters Ultraviolet disinfection Post aeration ■ Sludge lagoons 1. Continue to operate an existing 12.0 MGD wastewater treatment facility located south of Durham at the Durham County Triangle WWTP off NC Highway 55 in Durham County. The facility includes the following treatment components: 2. Discharge from said treatment works (via Outfall 001) into Northeast Creek, a Class WS-IV NSW water in the Cape Fear River Basin, at the location specified on the attached map. All previous NPDES Permits issued to this facility, whether for operation or discharge are hereby revoked. As of this permit issuance, any previously issued permit bearing this number is no longer effective. Therefore, the exclusive authority to operate and discharge from this facility arises under the permit conditions, requirements, terms, and provisions included herein. ADurham Co. Triangle WWTP - NC0026051 North SCALE 1: 24,000 USGS Quad Name: SW Durham Receiving Stream: Northeast Creek Stream Class: WS-IV NSW Subbasin: Catawba - 03-06-05 Facility Location Lat: 35°52’51” Long.: 78°53’50” ' '' ; 'Subs; 0 Outfall 001 ige .Dispi j'nds \w. Bl1* JCGr' CT Ops •fe , PI Mw- O y Ob? i / - - O:v- n.MLJ Of Sfo Permit NC0026051 EFFLUENT LIMITATIONS AND MONITORING REQUIREMENTSA. (1) MONITORING REQUIREMENTSEFFLUENT LIMITATIONS 12.0 MGD RecordingContinuous 5.0 mg/L 7.5 mg/L Daily Composite 15.0 mg/L10.0 mg/L Daily Composite 45.0 mg/L30.0 mg/L Daily CompositeTotal Suspended Solids2 EffluentDailyComposite3.0 mg/11.0 mg/L EffluentDailyComposite1.8 mg/L 5.4 mg/1 Grab EffluentDaily17 Mg/LTotal Residual Chlorine3 EffluentGrab2/MonthChloroform2 EffluentGrabWeeklyBromodichloromethane3 Grab EffluentWeekly EffluentDailyGrab200/100 ml 400/100 ml EffluentGrab EffluentGrab EffluentGrabPH5 EffluentCompositeTKN NO2-N +NO3-N Total Nitrogen6 Total Phosphorus6 Grab Effluent0.012 Mg/L EffluentGrab1800 Mg/L EffluentComposite EffluentComposite EffluentMonthlyChloride EffluentEffluent Pollutant Scan8 Annually EffluentQuarterlyComposite EFFLUENT CHARACTERISTICS Monthly Average Weekly Average Daily Maximum Measurement Frequency Composite Calculated Calculated Sample Type Sample Location1 Total Mercury7 Fluoride Total Copper Total Zinc Chronic Toxicity9 See notes on next page. No Limit (mg/L No Limit (pounds/month) Annual Limit: 100,452 pounds/year5 No Limit (mg/L) No Limit (pounds/month) Annual Limit: 10.204 pounds/year5 1-8 Mg/L 1.3 Mg/L 3/Week 3/Week Monthly Annually 3/Week Monthly Annually Weekly Weekly Monthly Monthly Daily Daily Daily 3/Week Composite Composite/ Grab Composite Composite Calculated Calculated Influent or Effluent Influent and Effluent Influent and Effluent Influent and Effluent Effluent Effluent Effluent Effluent Effluent Effluent Effluent Flow BOD,5-day. 20°C (April 1- October 31)2 BOD,5-day, 20°C (November 1 - March 31)2 NHs as N (April 1 - October 31) NH3 asN (November 1 - March 31) Dibromochloromethane3 Fecal Coliform (geometric mean) Dissolved Oxygen4 Temperature Beginning upon receipt of Engineer’s Certificate for completion of expansion above 6.0 MGD and lasting until expiration, the Permittee is authorized to discharge treated wastewater from Outfall 001. Such discharges shall be limited and monitored by the Permittee as specified below: Permit NC0026051 3. 9. There shall be no discharge of floating solids or visible foam in other than trace amounts. A. (2) INSTREAM MONITORING REQUIREMENTS MONITORING REQUIREMENTS Sample Location2Sample Type Grab Grab Grab Grab GrabPH Grab Grab GrabTKN GrabNO2 + NO3 GrabNH3 as N 2. INSTREAM CHARACTERISTICS Measurement Frequency Beginning upon the permit effective date and lasting until expiration, the Permittee shall monitor instream conditions as specified below1: Dissolved Oxygen Temperature Conductivity Fecal Coliform 3 /Week3 3/Week3 Upstream, DI, D2 Upstream, DI, D2 Upstream, DI, D2 Upstream, DI, D2 Upstream, DI, D2 Upstream, DI. D2 Upstream, DI, D2 Upstream, DI, D2 Upstream, DI, D2 Upstream, DI, D2 Total Phosphorus PO4 3 /Week4 Weekly4 Weekly4 Weekly4 Weekly4 Weekly4 3/Week3 3/Week3 Notes: 1. As a participant in the Upper Cape Fear River Basin Association, the instream monitoring requirements as stated above are waived. Should your membership in the association be terminated, you shall notify the Division immediately and the instream monitoring requirements specified in your permit shall be reinstated. Upstream = at NCSR 1102. DI = Downstream at NCSR 1100. D2 = Downstream at NCSR 1732. 3. Samples shall be collected 3/Week during June-September and Weekly during October-May. 4. Samples shall be collected during June-September only. Notes: 1. See Condition A. (2) for Instream monitoring requirements. 2. The monthly average effluent BODS and TSS concentrations shall not exceed 15% of the respective influent value (85% removal). Limit and/or monitoring applies only when chlorine is added to treatment system. 4. The daily effluent dissolved oxygen concentration shall not be less than 6.0 mg/L. 5. The pH shall not be less than 6.0 standard units nor greater than 9.0 standard units. 6. Refer to Special Condition A (4) for Total Nitrogen and Total Phosphorus Loading Calculations. 7. Mercury samples shall be analyzed using EPA Method 1631. 8. See Special Condition A. (7). Chronic Toxicity (Ceriodaphnia) at 90%: Feb., May, Aug., and Nov.; refer to Special Condition A (6). Permit NC0026051 A. (3) PERMIT RE-OPENER NUTRIENT CONTROLS A. (4) CALCULATION OF MASS LOADS The permitte shall calculate monthly and annual TN (or TP) loads as follows:a. Monthly TN (or TP) Loads = TN (or TP) x TMF x 8.34i. Where: TMF conversion factor, from (mg/L x MG) to pounds8.34 Annual TN (or TP) Load (Ib/yr) = Sum of 12 monthly TN (or TP) Loads for calendar year.ii. b. A. (5) REUSE OF TREATMENT PLANT EFFLUENT The effluent from the Durham County Triangle WWTP is authorized for onsite reuse subject to the following conditions: • The reuse water will be used onsite, within the fenced perimeter of the wastewater treatment plant with controlled public access, and for very specific internal uses (i.e., restrooms, HVAC system, and vehicle washdown). ■ The reuse water will be used by plant personnel who are trained and knowledgeable about reuse water. ■ An RPZ device will be required onsite to protect the potable water supply. ■ A water meter will be installed on the reuse line to monitor usage. ■ No runoff shall occur from the vehicle washdown area. ■ Reuse piping valves will be properly labeled and locking. TN (or TP) = the average Total Nitrogen (or Total Phosphorus) concentration (mg/L) of the composite samples collected during the month. the total monthly flow of wastewater discharged during the month (MG/mo) The Division may, upon written notification to the Permittee, re-open this Permit in order to incorporate or modify effluent limitations, monitoring and reporting requirements, and other permit conditions when it deems such action is necessary to implement nutrient management requirements such as those established through rule making or USEPA approval of TMDL(s). The permitte shall report monthly total nitrogen and total phosphorus results (mg/L and Ib/mo) in the appropriate discharge monitoring report for each month and shall report each year’s results (Ib/yr) with the December report for that year. Permit NC0026051 A. (6) QUARTERLY CHRONIC TOXICITY PERMIT LIMIT The effluent discharge shall at no time exhibit observable inhibition of reproduction or significant mortality to Ceriodaphnia dubia at an effluent concentration of 90%. The permit holder shall perform at a minimum, quarterly monitoring using test procedures outlined in the “North Carolina Ceriodaphnia Chronic Effluent Bioassay Procedure,” Revised February 1998, or subsequent versions or “North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure" (Revised-February 1998) or subsequent versions. The tests will be performed during the months of February, May, August, and November. Effluent sampling for this testing shall be performed at the NPDES permitted final effluent discharge below all treatment processes. If the test procedure performed as the first test of any single quarter results in a failure or ChV below the permit limit, then multiple-concentration testing shall be performed at a minimum, in each of the two following months as described in “North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure” (Revised-February 1998) or subsequent versions. The chronic value for multiple concentration tests will be determined using the geometric mean of the highest concentration having no detectable impairment of reproduction or survival and the lowest concentration that does have a detectable impairment of reproduction or survival. The definition of “detectable impairment," collection methods, exposure regimes, and further statistical methods are specified in the “North Carolina Phase II Chronic Whole Effluent Toxicity Test Procedure” (Revised- February 1998) or subsequent versions. All toxicity testing results required as part of this permit condition will be entered on the Effluent Discharge Monitoring Form (MR-1) for the months in which tests were performed, using the parameter code TGP3B for the pass/fail results and THP3B for the Chronic Value. Additionally, DWQ Form AT-3 (original) is to be sent to the following address: Attention: North Carolina Division of Water Quality Environmental Sciences Section 1621 Mail Service Center Raleigh, North Carolina 27699-1621 Completed Aquatic Toxicity Test Forms shall be filed with the Environmental Sciences Branch no later than 30 days after the end of the reporting period for which the report is made. Test data shall be complete, accurate, include all supporting chemical/physical measurements and all concentration/response data, and be certified by laboratory supervisor and ORC or approved designate signature. Total residual chlorine of the effluent toxicity sample must be measured and reported if chlorine is employed for disinfection of the waste stream. Should there be no discharge of flow from the facility during a month in which toxicity monitoring is required, the permittee will complete the information located at the top of the aquatic toxicity (AT) test form indicating the facility name, permit number, pipe number, county, and the month/year of the report with the notation of “No Flow" in the comment area of the form. The report shall be submitted to the Environmental Sciences Branch at the address cited above. Should the permittee fail to monitor during a month in which toxicity monitoring is required, monitoring will be required during the following month. Should any test data from this monitoring requirement or tests performed by the North Carolina Division of Water Quality indicate potential impacts to the receiving stream, this permit may be re-opened and modified to include alternate monitoring requirements or limits. NOTE: Failure to achieve test conditions as specified in the cited document, such as minimum control organism survival, minimum control organism reproduction, and appropriate environmental controls, shall constitute an invalid test and will require immediate follow-up testing to be completed no later than the last day of the month following the month of the initial monitoring. Permit NC0026051 Bis (2-chloroethyl) ether Bis (2-chloroisopropyl) ether Bis (2-ethylhexyl) phthalate 4-bromophenyl phenyl ether Butyl benzyl phthalate 2-chloronaphthalene 4-chlorophenyl phenyl ether Chrysene Di-n-butyl phthalate Di-n-octyl phthalate Dibenzo(a,h)anthracene 1.2- dichlorobenzene 1.3- dichlorobenzene 1.4- dichlorobenzene 3,3 - dichlorobenzidine Diethyl phthalate Dimethyl phthalate 2.4- dinitrotoluene 2,6-dinitrotoluene 1,2-diphenylhydrazine Fluoranthene Fluorene Hexachlorobenzene Hexachlorobutadiene Hexachlorocyclo-pentadiene Hexachloroethane Indeno(l,2,3-cd)pyrene Isophorone Naphthalene Nitrobenzene N-nitrosodi-n-propylamine N-nitrosodimethylamine N-nitrosodiphenylamine Phenanthrene Pyrene 1,2,4-trichlorobenzene Trans-1,2-dichloroethylene 1.1 -dichloroethylene 1.2- dichloropropane 1.3- dichloropropylene Ethylbenzene Methyl bromide Methyl chloride Methylene chloride 1.1.2.2- tetrachloroethane Tetrachloroethylene Toluene 1.1.1 -trichloroethane 1.1.2- trichloroethane Trichloroethylene Vinyl chloride Acid-extractable compounds: P-chloro-m-cresol 2-chloroph enol 2.4- dichlorophenol 2.4- dimethylphenol 4.6- dinitro-o-cresol 2.4- dinitrophenol 2-nitrophenol 4-nitrophenol Pentachlorophenol Phenol 2.4.6- trichlorophenol Base-neutral compounds: Acenaphthene Acenaphthylene Anthracene Benzidine Benzo(a)anthracene Benzo (a) pyrene 3,4 benzofluoranthene Benzo(ghi)perylene Benzo (k) fluoranthene Bis (2-chloroethoxy) methane determine whether parameters are present in concentrations greater than applicable standards and criteria. Samples shall represent seasonal variations. Unless otherwise indicated, metals shall be analyzed as “total recoverable.” Ammonia (as N) Chlorine (total residual, TRC) Dissolved oxygen Nitrate/Nitrite Kjeldahl nitrogen Oil and grease Phosphorus Total dissolved solids Hardness Antimony Arsenic Beryllium Cadmium Chromium Copper Lead Mercury Nickel Selenium Silver Thallium Zinc Cyanide Total phenolic compounds Volatile organic compounds: Acrolein Acrylonitrile Benzene Bromoform Carbon tetrachloride Chlorobenzene Chlorodibromomethane Chloroethane 2-chloroethylvinyl ether Chloroform Dichlorobromomethane 1,1 -dichloroethane 1,2-dichloroethane A. (7) EFFLUENT POLLUTANT SCAN The Permittee shall perform an annual Effluent Pollutant Scan for all parameters listed in the attached table. The analytical methods shall be in accordance with 40 CFR Part 136 and shall be sufficiently sensitive to Test results shall be reported to the Division in DWQ Form- A MR-PPA1 or in a form approved by the Director within 90 days of sampling. The report shall be submitted to the following address: NC DENR / DWQ / Central Files, 1617 Mail Service Center, Raleigh, North Carolina 27699-1617. Lat. 35° 52’51” N Long. 78° 53’ 50” W Correspondence The Raleigh Regional Office (RRO) conducted several site visits during this permit term to evaluate compliance. A Staff Report was also prepared in conjunction with the permit renewal. RRO finds the facility to be in compliance with the NPDES permit and recommends renewal. DENR/DWQ FACT SHEET FOR NPDES PERMIT DEVELOPMENT NPDES No. NC0026051 Fact Sheet NPDES NC002605I Renewal Page 1 Applicant/Facility Name: Applicant Address:_____ Facility Address:______ Permitted Flow________ Type of Waste:________ Facility/Permit Status: County: Regional Office:_______ State Grid ZUSGS Quad: Permit Writer:________ Date: Receiving Stream: Stream Classification: 303(d) Listed? Subbasin:__________ Drainage Area (mi2): 7Q10(cfs) 30Q2 (cfs)_________ Average Flow (cfs): IWC (%): Raleigh (RRO) D23NW/SWDurham Teresa Rodriguez May 31,2006 _______Facility Information___________________________ Durham County Triangle WWTP_______________________ 120 Parrish Street, Suite 110 Durham, NC27701_____________ 5926 NC Highway 55 East, Durham, North Carolina 27713 12.0 MGD___________________________________________ Domestic (70%) and industrial (30%) with pretreatment program Class IV /Active; Renewal______________________________ Durham County_______________________________________ __________Miscella neons Northeast Creek WS-IV NSW Yes__________ 03-06-05 18___________ 0____________ 0.9__________ 20.0 _______ 100% BACKGROUND The Durham County Triangle WWTP (Class IV) has a permitted flow of 12.0 MGD. The permit was renewed in May 2002 for 6.0 MGD with authorization to expand to 12.0 MGD. The plant expansion/upgrade was completed in June 2005. The Permittee submitted Standard Form A on November 1, 2005 in order to request renewal of the permit. Durham County has a full pretreatment program (15 SIUs) with the Division of Water Quality’s Pretreatment Unit and will continue to implement this program in the new permit term. The most recent staff report from the Fayetteville Regional Office (June 1, 2001) recommends renewal of the NPDES permit. The facility has not requested any changes to the permit. Instream Monitoring, Verification of Existing Conditions and DMR Data Review This facility discharges to Northeast Creek in subbasin 03-06-05 in the Cape Fear River Basin. The receiving stream is classified WS-IV NSW at this point. Northeast Creek is listed on the 2002-303(d) list as impaired for aquatic life due to turbidity and for recreation due to fecal coliform. Since the new plant started operations in June 2005 DMR data was reviewed for the period of June 2005 to March 2006. Flow averaged 4.08 MGD, BOD averaged 3.9 mg/L, TSS averaged 2.0 mg/L, ammonia averaged 0.26 mg/L, total nitrogen averaged 3.18 mg/L and total phosphorus averaged 0.35 mg/L. No limits violations were reported for this time period. Durham County is a member of the Upper Cape Fear River Coalition and instream monitoring requirements of the NPDES permit are therefore waived as long as the membership in the association continues. PERMITTING STRATEGY SUMMARY OF PROPOSED CHANGES In keeping with Division policies, the following will be incorporated into the permit: 1 • Remove chloride limit; reduce monitoring frequency to monthly • Weekly average limit for fluoride • Annual effluent pollutant scan • Nutrient monitoring as per Cape Fear Nutrient Permitting Strategy Reasonable Potential Analysis (RPA) The Division conducted a reasonable potential analyses to determine the reasonable potential for toxicants to be discharged by this facility, based on DMR data from June 2005-March 2006. Calculations included parameters listed in the previous permit and pre-treatment documents to include: arsenic, cadmium, chromium, chloride, cyanide, fluoride, lead, mercury, molybdenum, nickel, silver, selenium, copper, and zinc. Results suggest no reasonable potential for the facility to discharge arsenic, cadmium, chromium, cyanide, lead, mercury, molybdenum, chloride, selenium or silver. Copper and zinc show reasonable potential, but are action level standards and the facility shows no toxicity problems, so monitoring only will remain in the permit. Fluoride showed reasonable potential. A weekly average limit of 1800 /ig/L will be implemented for fluoride. Fact Sheet NPDES NC002605I Renewal Page 2 Waste Load Allocation (WLA) The Division prepared the last WLA in 1995. Previous and current effluent limits were based on guidelines and water quality standards. The Division has judged previous parameters and limits to be appropriate for renewal with some exceptions. Changes to toxicant monitoring are discussed in the Reasonable Potential Analysis section. In addition, an annual pollutant scan will be added such that the Permittee can collect the necessary data required by EPA Form 2A throughout the permit term. This condition is now standard on all major municipal permits in North Carolina. Cape Fear Nutrient Permitting strategy For the 2006 permit renewal cycle the Division developed a permitting strategy to address nutrient concerns in the Cape Fear River Basin. This strategy is being applied at permit renewal to existing discharges on the basin. The strategy calls for additional nutrient monitoring and reporting to support the efforts of the Modeling and TMDL Unit in developing special studies and TMDL projects. Dischargers in the Jordan Lake watershed will monitor TN and TP 3 times per week, report nitrogen species, and report TN and TP as both concentration and mass loads. The permit also includes a re-opener special condition. In the event that the Environmental Management Commission adopts a nutrient management strategy or the EPA approves a TMDL in the coming permit term, the condition allows the Division to re-open affected permits to set nutrient limits and related conditions accordingly. The facility has receiv^fto^^tices of Violation (NOVs) or enforce^^t actions in the past two years, and has been in compliance with its toxicity limit during this permit term with the exception of one failure in January 2003, which was passed the following month. PROPOSED SCHEDULE FOR PERMIT ISSUANCE NPDES DIVISION CONTACT ANAME:DATE: Regional Office Comments NAME: DATE: SUPERVISOR: DATE: Draft Permit to Public Notice: Permit Scheduled to Issue: If you have questions regarding any of the above information or on the attached permit, please contact Teresa Rodriguez at (919) 733-5083 ext. 553. June 7, 2006 July 31,2006 Fact Sheet NPDES NC0026051 Renewal Page 3 Outfall 001 Qw = 12MGD PARAMETER PQL Units REASONABLE POTENTIAL RESULTS RECOMMENDED ACTION Allowable CwUDet.Max Pred Cwn Acute:N/A Arsenic NC 50 ug/L 0 0 N/A All samples BDL Chronic:50 Acute 15 Cadmium NC 2 15 ug/L 0 0 N/A All samples BDL Chronic:2 Acute:1,022 Chromium NC 50 1,022 ug/L 00 N/A Ml samples_BDL Chronic:50 Acute:7 Copper NC 7 AL 7.3 RP exists, but AL standard and no toxicity problemsug/L 31.9 Chronic:7 Acute:22 Cyanide NC 5 N 22 10 ug/L 0 0 N/A All samples BDL Chronic:5 Acute:N/A Fluoride NC 1,800 ug/L 1,848.0 Chronic:1,800 Acute:34 Lead NC 25 N 33.8 ug/L 0 0 N/A All samples_BDL Chronic:25 Acute:N/A No RP. remove limit, continue monitoring Mercury NC 12 ng/L 43 22 11.4400 Chronic:12 Acute:N/A Molybdenum 3,500 10Aug/L 10 121.7 No RP. Chronic:3,669 Acute:261 Nickel NC 88 261 ug/L 69.8 No RP Chronic:88 Limited data set Acute:N/A Chloride NC 250 No RP;_remove limit but maintain monjtoring.ug/L 44 44 128 8 Chronic:250 Acute:NoRP56 Selenium NC 5.0 56 ug/L 3.5 Chronic:5 Acute:1 Silver NC 0.06 AL 1 23 ug/L 0 0 N/A All samples BDL Chronic:0 Acute:67 NC RP exists, but AL standard and no toxicity problemsZinc50AL67ug/L 293 4 Chronic:50 " Freshwater Discharge TYPE (D ' Legend: C = Carcinogenic NC = Non-carcinogenic A = Aesthetic 0 12 0 0.5 0.9 20 100 97.382 95.385 48.187 npdes rpa 2004031.xls, rpa 5/31/2006 •f^SONABLE POTENTIAL ANAlWi^ STANDARDS & CRITERIA (2) NCWOS/ HFAVt Chronic Acute Time Period Ow (MGD) 7Q10S(cfs) 7Q10W(cfs) 3002 (cfs) Avg. Stream Flow, QA (cfs) Ftec'ving Stream Northeast Creek Note: n<12 Limited data set Durham County Triangle WWTP NC0026051 WWTP Class IV IWC(%) © 7OWS © 7Q10W @ 3002 © OA Stream Class WS-IV NSW 10 1 Note: n<12 Limited data set 9 9 Note: n<12 Limited data set 10 3 Note: nd 2 10 10 Note: n<12 Limited data set 10 10 Note: n<l2 Limited data set CyanideCopper BDL=1/2DLDateDataData -3- BDL=1/2DL 4.0 12.0 12.0 10.0 4.0 6.0 5.0 6.0 4.0 3.0 Mult Factor = Max. Value Max. Pred Cw 3.4383 6.6000 0.5210 10 2.6600 12.0 ug/L 31.9 ug/L Mult Factor = Max. Value Max. Pred Cw N/A 0.0 ug/L N/A ug/L 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 Date Jun-2005 Jul-2005 Aug-2005 Sep-2005 Oct-2005 Nov-2005 Dec-2005 Jan-2006 Feb-2006 Mar-2006 Apr-2006 4 12 12 10 4 6 5 6 4 3 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 npdes rpa 2004031 ,xls, data 5/31/2006 Results Std Dev. Mean C.V. n Results Std Dev. Mean C.V. n ^f^SONABLE POTENTIAL AN^Y^ NO DATA NO DATA NO DATA 0 Fluoride Lead Date BDL=1/2DL ;; -4- H' Mult Factor = Max. Value Max. Pred Cw Mult Factor = Max. Value Max. Pred Cw 1020 1150 1200 1200 1100 800 900 700 700 BDL=1/2DL 1020.0 1150.0 1200.0 1200.0 1100.0 800.0 900.0 700.0 700.0 205.2505 974.4444 0.2106 9 1.5400 1200.0 ug/L 1848.0 ug/L npdes rpa 2004031.xls, data 5/31/2006 N/A 0.0 ug/L N/A ug/L 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 Date Jul-2005 Aug-2005 Sep-2005 Oct-2005 Nov-2005 Dec-2005 Jan-2006 Feb-2006 Mar-2006 Apr-2006 May-2006 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 8 Results Std Dev. Mean C.V. n Results Std Dev. Mean C.V. n I DataDataI R^S^IABLE POTENTIAL ANAL^S^ I NO DATA NO DATA NO DATA 0 Mercury Molybdenum Data Jul-2005 Aug-2005 Sep-2005 Oct-2005 <Nov-2005 Dec-2005 < Jan-2006 Feb-2006 < 1 Mar-2006 -5- Date Jun-2005 Mult Factor = Max. Value Max. Pred Cw 1.0526 1.2153 0.8661 43 2.20 5.2 ng/L 11.4 ng/L 64 64 56 72 62 47 36 28 71.0 70.0 BDL=1/2DL 64.0 64.0 56.0 72.0 62.0 47.0 36.0 28.0 71.0 70.0 Mult Factor = Max. Value Max. Pred Cw 1.6900 72.0 ug/L 121.7 ug/L 15.26 57.00 0.27 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 BDL=1/2DL 2.1 2.9 2.2 1.3 2.1 1.9 1.3 5.2 1.8 1.9 1.2 0.5 0.5 0.5 4.7 0.5 0.5 0.5 1.8 0.5 0.5 0.5 0.5 0.5 1.3 0.5 1.6 1.0 1.8 0.5 1.0 0.5 1.0 0.5 0.5 0.5 1.0 1.4 0.5 0.5 0.5 0.5 1.4 R&lsONABLE POTENTIAL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 Results Std Dev. Mean C.V. n npdes rpa 2004031 ,xls, data 5/31/2006 Results Std Dev. Mean C.V. n 0 Date Jun-2005 Jul-2005 Aug-2005 Sep-2005 Oct-2005 Nov-2005 Dec-2005 Jan-2006 Feb-2006 Mar-2006 Apr-2006 May-2006 Data ^1 2-11 2.85 "■ 2.17 1.32 ; 2.12 1.88 B 128 5.2 1.8 1.9 1.2 1.0 1.0 1.0 4.7 1.0 1.0 1.0 1.8 1.0 1.0 1.0 1.0 1.0 1.3 1.0 1.6 1.0 1.8 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.4 1.0 1.0 1.0 1.0 1.4 Nickel Chloride Data Jul-2005 Aug-2005 Sep-2005 Oct-2005 Nov-2005 Dec-2005 Jan-2006 1 Feb-2006 S;Mar-2006 -6- Date Jun-2005 Mult Factor = Max. Value Max. Fred Cw Mult Factor = Max. Value Max. Fred Cw BDL=1/2DL 2.5 5.0 16.0 5.0 6.0 2.5 2.5 2.5 2.5 4.0 4.1369 4.8500 0.8530 10 4.3600 16.0 ug/L 69.8 ug/L 92 86 84 92 85 73 81 76 85 69 81 79 84 108 102 95 96 91 109 99 87 90 93 105 94 108 97 87 109 92 88 103 114 98 100 81 94 96 106 92 107 100 106 96 BDL=1/2DL 92.0 86.0 84.0 92.0 85.0 73.0 81.0 76.0 85.0 68.7 81.0 78.8 84.2 108.0 102.0 95.4 96.0 90.5 109.0 99.0 87.0 90.0 93.0 105.0 94.0 108.0 97.0 87.0 109.0 92.0 88.0 103.0 114.0 98.0 100.0 81.0 94.0 96.0 106.0 92.0 107.0 100.0 106.0 96.0 npdes rpa 2004031 ,xls, data 5/31/2006 1.1300 114.0 ug/L 128.8 ug/L 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 5 10 16 10 6 5 5 5 5 4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 10.5979 93.4000 0.1135 44 rWs^able potential anal Results Std Dev. Mean C.V. n Results Std Dev. Mean C.V. n i Date Data Jun-2005 < Jul-2005 < Aug-2005 Sep-2005 < Oct-2005 Nov-2005 < Dec-2005 < Jan-2006 < Feb-2006 < Mar-2006 Apr-2006 May-2006 SilverSelenium Data BDL=1/2DLDate * -7- 2 2 2 2 2 2 2 2 2 2 BDL=1/2DL 1.0 1.0 2.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Mult Factor = Max. Value Max. Pred Cw 0.3162 1.1000 0.2875 10 Mult Factor = Max. Value Max. Pred Cw N/A 0.0 ug/L N/A ug/L 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 Sep-2005 Oct-2005 Nov-2005 Dec-2005 Jan-2006 Feb-2006 Mar-2006 Apr-2006 May-2006 1.7600 2.0 ug/L 3.5 ug/L 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 npdes rpa 2004031.xls, data 5/31/2006 Date Jul-2005 Results Std Dev. Mean C.V. n Results Std Dev. Mean C.V. n i i 1 Data !< Aug-2005 < I ^ffcoNABLE POTENTIAL I I NO DATA NO DATA NO DATA 0 Zinc Data -8- Mult Factor = Max. Value Max. Pred Cw 163 148 98 174 180 173 124 102 98 112 BDL=1/2DL 163.0 148.0 98.0 174.0 180.0 173.0 124.0 102.0 98.0 112.0 fOs^iable potential anal^s 33.9470 137.2000 0.2474 10 1.6300 180.0 ug/L 293.4 ug/L npdes rpa 2004031.xls, data 5/31/2006 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 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 59 60 199 200 Results Std Dev. Mean C.V. n Date I Jun-2005 Jul-2005 ; Aug-2005 ' Sep-2005 Oct-2005 : Nov-2005 Dec-2005 | Jan-2006 I Feb-2006 . Mar-2006 Apr-2006 May-2006 Jun-2006