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Home My WebLink AboutNC0021211_INSTREAM ASSESSMENT_19890228 NPDES DOCYNENT SCANNIN& COVER SHEET NPDES Permit: NC0021211 Graham WWTP Document Type: Permit Issuance Wasteload Allocation Authorization to Construct (AtC) Permit Modification Speculative Limits 201 Facilities Plan Instream Assessment (67B) Environmental Assessment (EA) Permit History Document Date: February 28, 1989 Thies document i�printed on reuse paper-ignore any content on the reverses e�ide iy DIVISION OF ENVIRONMENTAL MANAGEMENT February 28, 1989 MEMORANDUM TO: Steve Mauney THRU: David Vogt Trevor Clement Ken Eagleson FROM: Mike Scoville M5 SUBJECT: Instream Assessment for the City of Graham WWTP NPDES No. NCO021211 Alamance County Summary The City of Graham has amended their request for a first-time SOC to increase their effluent limitations of cadmium, chromium, cyanide, and lead. An increase of metals limits would allow the facility to make the remaining reserve of it ' s design capacity available to future contributors (flow information is shown in Table 1 ) . The Winston-Salem Regional Office has proposed increases of the cad- mium, chromium, cyanide, and lead limits. The facility has experienced diffi- culty meeting it 's NPDES cyanide and cadmium limits, but is consistently com- pliant with the final limitations for other parameters. In considering whether to permit additional wasteflow, Technical Services recommends that the Division require Graham' s discharge to protect against acute toxicity while providing relief from the standard of no effect . DEM recently received a request from the City for a permit modification to relocate their discharge to the Haw River , where the metal limitations will be slightly less stringent and more easily met . Analysis and Discussion The City of Graham WWTP discharges to Town Branch (C-NSW) approximately 0.5 mile above it ' s confluence with the Haw River . At the discharge point, USGS flow statistics indicate a drainage area of 3.B1 sq . mi . , an average flow of 3.4 cfs, and a 7Q10 of 0.07 cfs. Due to the effluent ' s dominance of the streamflow, met- als limits approximate the North Carolina water quality standards. An analysis of the impact of oxygen-consuming waste at the SOC wasteflow is not necessary because the permit limitations were originally set with respect to a 3.5 MOD design flow. These limits are not being violated and do not need modification. However, since temporary relief is needed for some of the metals limits, Techni- cal Services recommends that these limits be increased only to the maximum con- centrations that will protect against acute toxic effects in the receiving waters. These concentrations are derived by halving the Final Acute Values (FAV) a z t found in the USEPA Ambient Water Quality Criteria documents for each of the respective metals. The cyanide and cadmium limits recommended by the Region are acceptable for the SOC; they are equal to or less than half of the FAVs recommended by EPA. Because the facility has consistently met it 's NPDES chromium limit, Technical Services recommends that the 50 ug/1 limit be maintained in the SOC. The EPA FAV/2 (34 ug/1 ) is recommended as the SOC lead limit , since any amount greater than this will cause adverse toxic effects instream. A summary of the proposed and recommended metal limits as well as the EPA acute values are shown in Table 1 . Recommendations Technical Services recommends SOC limits of 13 ug/l for cyanide, 5 ug/l for cadmium, 50 ug/l for chromium, and 34 ug/1 for lead. These effluent limitations will cause the N.C. instream water quality standards to be exceeded, but will Protect against acute toxicity effects in the receiving water . It should be noted that any toxic effects resulting from increased metal concentrations are expected to be confined to the 0.5 mile reach of Town Branch , where the streamflow pro- vides very little dilution. However , no additional wastewater contributors should be accepted by the Graham WWTP that may cause a violation of these limits. It is the recommendation of Technical services that wasteflow additions be lim- ited to domestic wastewater and industrial wastewater that is oroven to have a composition simi.lar to domestic wastewater . cc: Steve Tedder Kent Wiggins Steve Reid ,City of Graham WLA File TABLE 1 . Instream Assessment Summary for the City of Graham Design Capacity 3.50 MGD Pre-SOC Flow (2/88-12/38) 1 .40 MGD Remaining Reserve Flow 2. 10 MGD Maximum Observed Recommended Current Monthly Proposed EPA SOC Metal Limit Conc . Limit' FAV/2 Limit Cyanide 5 6 31 31 3 Cadmium 2 5 5 5 5 Chromium 50 6 130 -- 50 Lead 25 23 63 34 34 All units are ug/l . -`SOC limits proposed by the Winston-Salem Regional Office. IC Request Form for In-stream Assessment for 67B NAME OF FACILITY_ IL OT 1104APyt _W01P __ SUBBASIN UE -0Z_ COUNTY)f}PnA rJ CQ REGION WSRO _ DESIGN FLOW RECEIVING STREAM BACKGROUND DATA A. Why is SOC needed? (Facility is out of compliance with which effluent limits?) i /. / � �2 i �.� �s P2 e gN,'eQe !! � nn ,J /}yia✓t a ¢ e.. Ta ?�U'SJ C.B'd.%ua.. B. History of SOC requests : SOC •Rx kes Nd, Wlgj6V SOC pRg({' acQ bJ- Ne-ea rss'44 �e4kesf- Il'71SI Sw�i K; ec{ Jo A„,e,ld SOC �e5ues ��-B SoC. 11 . Monthly Average waste flow prior to any SOC /• 7 _ mgd Time period averaged �� )Si $ _ thru fP-, 1548 2 . Previously approved SOC ' s : NA Date: flow: ,mgd Date :_ flow: _____mgd total of previously approved SOC flow: mgd 3 . Flows lost from plant flow: _mgd (facilities that have gone off line) f '\ CDR[Se.J 4 . Current SOC request flow:_ �. � mgd eLAif RegeRJC 5 . Total plant flow post-SOC V -- (sum of original flow and SOC flow minus losses) flow: 3, S mgd 6. Is this an accurate flow balance for plant? Why/why not? v25 . PIAth UQS I 1SnI 1 3. Sn,s�. . /jn1�J Av"t- /on �r�g was / ��5�• C. Please attach DMR summary for past year for all permitted parame- ters . If possible , include reports from previous years if facility has been under SOC for more than a year . CURRENT SOC-REQUEST A . Request is for domestic or industrial waste? If it is a combin- ation, //plea,�st,,e specify percentag(ees. ,J� �iQUl7F+"/JI�J 14' 60 nb;t /-/, di1/ a99 LJ 05 hes ('�Qyy keS 11 ,5 tl�2 I/`a. Re+n/�Inl,� / 2�PS Pl1U.Z p� 1�04�� 2.1,,.5�� 6e Av,"'111e C _ asQ b� ys�e cvN� /o2r B . What type of industry? Please attach any pertinent data. Hb,dasjgi-/sS. G'^/„f/..�v.5NJ7f�d�,p. � sh�;e(/ covlfiR�fti xgJ/�sJ).JLPL (� tRdojG.4/e �o/d 6./e-..c �es.edye'tSe fofo J;44 Ai/ C'OI✓cF✓OXAIAI .0 U n 6e clds=! Dome '%e: 5o 'Zces SAO./e( pelc IVA C The region roposes the following SOC limits : &ow l fly Ave.cflyeS BOD5 / 7- mg/l NH3 l mg/l \DO_ 5 mg/1 �m: ✓,1 }" � A141 Li,, $ 4s TSS-- -mg/1 A) fecal coliform C) __#/100m1 Ape- �a/a - PPari,�;�- pH � '� sU CRe,,,�Q\/� C��s; $bIIN/}l� mew other parameters GHQ}Nidf. �Q�3 C'gJdls.�iu.r, J; . iu�0 13' D. What is the basis for these limits? _1�( P� d- has AN AV90A�E dew oqQ 7.b flZ09'eJ CJ(f��R// 3/5_ Atx�j /Je,e,n; 4""Id ,Pgddr P4_ 5�nr� GJC�7 � /'V U �2ce�ucc� 14ty 4ff1'C47/oN ?l�s been Aoe -4 /Jed/an.. LL7oa /ns �94�� A 't.' c447C /VA T��O/7`L`*a /-�ty�/Ue2. �f- �s�i.4>�'� i✓",�'0 7�v is neat reese, Al �Tf13 OF �rFIATrI RECEIVED N.C. Deal. N CD P.O. Drawer 357 201 South Main Street Graham, North Carolina 27253 (919) 228-8362 Reg;on:;( iJfiit:8 January 17, 1989 Mr. Paul Wilms, Director Division of Environmental Management North Carolina Department of Natural Resources and Community Development PO Box 27687 Raleigh, NC 27611-7687 Dear Mr. Wilms, This letter is to amend my request of August 9, 1988, for a SPECIAL ORDER OF CONSENT (SOC) . I was advised by the Winston-Salem Regional Office that my SOC would not be presented to the Environmental Management Commission and that it would have to be revised to a 67-B SOC. We feel our plant has operated well and we should not be placed under a restricted wastewater flow moratorium. It is under- stood that during the life of the SOC certain industrial wastes with metals in the wastewater flo:v would be limited. In any event, all industrial contributors would have to be reviewed individually. If it is necessary for the City Council to pass another resolution authorizing me to sign the 67B SOC, please advise. We propose to move the effluent to Haw River, will submit NPDES applications i-*i the near future. Sincerely, Ray Fog Zman'-/ City Manager pcn cc: M. Steven Mauney -- -- --- Water Quality Supervisor RF/dd