The URL can be used to link to this page

Home My WebLink AboutNC0007552_Request for Additional Information_20170714Water Resources p Environmental Quality July 14, 2017 CERTIFIED MAIL 7002 0860 0006 58361066 RETURN RECEIPT REQUESTED Ms. Anne -Marie Knighton, Town Manager Town of Edenton P.O. Box 300 Edenton, NC 27932 Dear Ms. Knighton: ROY COOPER Governor MICHAEL S. REGAN Secretary S. JAY ZIMMERMAN Director Subject: Request for Additional Information Renewal Application Freemason WTP NPDES permit NC0007552 Chowan County The Division has reviewed your application, received on June 29, 2017, for renewal of NPDES permit NC0035173. To enable us complete our review in accordance with N.C.G.S. 143-215.1 and 15A NCAC 2H.0105, please provide additional or revised information to address the following comments: 1. Please provide the discharge alternative evaluation required by the Condition A. (4.) of your permit issued October 15, 2014. 2. Please provide five (5) days of Total Hardness (CaCO3 or (Ca + Mg)) data for the effluent at Outfall 001. 3. If flow is present in the receiving stream, please provide five (5) days of Total Hardness (CaCO3 or (Ca + Mg)) data upstream from Outfall 001. 4. Review of our records indicates that there is no stream flow data documented for the receiving stream. Please provide a 7Q10 and 30Q2 at the location of Outfall 001 [36.0644°, -76.6139°], for the unnamed tributary "Filbert Creek" to Edenton Bay from the following contact with the US Geological Survey: J. Curtis Weaver, Hydrologist, PE USGS North Carolina Water Science Center 3916 Sunset Ridge Road Raleigh, NC 27607 Phone: (919) 571-4043 // Fax: (919) 571-4041 E-mail address--lcweavergusgs.gov Internet address -- http://nc.water.us sg .gov/ The NC 2007-2014 Water Quality Standard (WQS) Triennial Review was approved by the NC Environmental Management Committee (EMC) on November 13, 2014. The US EPA subsequently approved the WQS revisions on April 6, 2016 with some exceptions. The NC Division of Water Resources is required to implement the new dissolved metal standards in all permits public noticed after April 6, 2016. State of North Carolina I Environmental Quality 1617 Mail Service Center I Raleigh, North Carolina 27699-1617 919-707-9000 Ms. Knighton July 14, 2017 Page 2 of 2 The new standards for most metals include acute standards Furthermore, the freshwater standards for several metals are expressed as the dissolved form of the metals, and seven metals have hardness - dependent equations. As a result, the Division will need site-specific effluent hardness data and mstream hardness data, upstream of the discharge, for each facility monitoring these metals in order to calculate permit limitations. The metal of concern for this permit renewal is Copper. To evaluate dissolved Copper, a Reasonable Potential Analysis (RPA) was conducted using data for 4 '/z years (Dec2012—May2017) Results indicated a reasonable potential to exceed the new dissolved metal standard for Copper. Consequently, the fallowing daily maximum limits (acute standard) and monthly average limits (chronic standard) for Total Copper could be applied for this permit renewal: Parameter Outfall Monthly Average Limit Daily Maximum Limit Copper 001 7.88 µg/L 10 47 µg/L To calculate these limits a default hardness of 25 mg/L was entered for both the effluent and upstream values. Additionally, a 7Q10 of zero was used for this calculation For a summary of this information, please see the attached "Dissolved to Total Metal Calculator" Incidentally, the additional information requested will be used in a recalculation for the draft permit. If no response is received within 60 calendar days [per 15A NCAC 2H.0I07(b)], the permit will be renewed without the benefit of the requested additional information. Therefore, a default hardness of 25 mg/L and a 7Q10 of zero will be used to calculate effluent limits for Copper as indicated. If you have any questions, please contact Derek Denard at 919-807-6307 or email at derek.denard(&ncdenr.gov. Sincerely, i Derek Denard, Environmental Specialist Compliance & Expedited Permitting Unit Division of Water Resources, NCDEQ he Central Files NPDES Program Files WaRO Files ec Robert Bullock [robert bullock@ncdenr go-] Scott Vinson [scott vmson@ncdenr gov] Anne -Mane Knighton [anne-mane kmghton@ncmail net] Date 7/14/2017 FACILITY: Town of Edenton - Freemason WTP NPDES PERMIT NC0007552 Dissolved to Total Metal Calculator In accordance with Federal Regulations, permit l@aratations must he written fit Total Metals per 40 CFR 122A5(c) Receiving Receiving Rec Stream Stream Stream NPDES Total Suspended Combined Combined InsVeam InsVeam Solids Hardness Hardness Wastewater Wastewater Upstream Upstream Hard Avg (mg/L) = EFF Hard Avg (mg/L) = Effluent 25 25 PARAMETER Dissolved Metals US EPA Translators- using Default Partition Coefficients streams Maximum Allowable Effluent Concentration (MAEC) as a 1P 9 7 =DiwolvedMetal-Translator COMMENTS (identify parameters to PERCS Branch to maintain in facility's LTMP/STMP) Chronic Acute Chronic Acute uq/I u /I u /I [ugill Cadmium (d) 015 082 0 252 059 324 Cd -Trout stream 0151 051 0 252 059 201 Chromium III (d)(h) 24 183 0202 11773 90508 Chromium VI (d) 11 16 1 000 11 00 1600 Chromium, Total (t) (mg/L) 0 0000 N/A N/A Copper (d)(h) 27 36 0 348 788 1047 Lead (d)(h) 054 14 0 184 294 7549 Nickel (d)(h) 16 145 0 432 3723 33521 Ni - WS streams (t) 25 NIA Silver (d)(h,acute) 0061 0 30 1 000 0061 030 Zinc (d)(h) 36 36 0 288 12673 12571 Beryllium 651 65 1 000 651 65 Arsenic (d) 150 340 1 000 150 340 (d) = dissolved metal standard See 15A NCAC 02B 0211 for more information (h) = hardness -dependent dissolved metal standard See 15A NCAC 02B 0211 for more information (t) = based upon measurement of total recoveable metal See 15A NCAC 02B 0211 for more information The Human Health standard for Nickel in Water Supply Streams is 25 mg/L which is Total Recoverable metal standard The Human Health standard for Arsenic is 10 pg/L which is Total Recoverable metal standard summer summer 70110 1010 Flow Limit -Fixed Value- chronic Acute Concentration Concentration Hardness Average 7010 (CFS) (MGD) [MGD) MGD (mg/L) (mg/L) (mg/L) (Chronic) (Acute) Average (mg/L) (mg/L) 0 0000 0 0000 0 0000 0 0090 10 25 000 25 000 100 0000 100 0000 25 25