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Home My WebLink AboutNC0021253_WASTELOAD ALLOCATION_19860801 NPDES DOCUWENT SCANNING COVER $MEET NPDES Permit: NC0021253 Havelock WWTP Document Type: Permit Issuance Wasteload Allocation Authorization to Construct (AtC) Permit Modification Engineering Alternatives Analysis 201 Facilities Plan Instream Assessment (67B) Correspondence re: Mercury Permit History Document Date: August 1, 1986 Tlaie document In printed oa reuse paper-ignore any content oa the reverse gaide NPDES WASTE LOAD ALLOCATION Engineer Datp Rec. _ ,,/� L SEz 8 B 30 0 Facility Name: r To w it 1P 44a./�� oG l� Date Y-17 -p 6 � Existing ® Z. _ . Permit No. : Nc Z 1 S 3 Pipe No. : / County: C �`0.dJ en Proposed O Design Capacity (MGD) : 1• S Industrial (% of Flow) : a Eomestic ( % of Flow) : Receiving Stream: Ea 4_ PrbA, $1eC.u.1 Crd� kss: C- -90 Sub-Basin: 0 30 Reference USGS Quad: H 31 (Please attach) Requestor: L.1 S e� C t 4Mc-A Regional. Office wa l` �O 'Guideline limitations, if applicable, are to be listed on the back of this form. ) Design Temp.: Drainage Area (mi2) : Avg. Streamflow (cfs) : 7Q10 (cfs) Winter 7Q10 (cfs) 30Q2 (cfs) Location of D.O. minimum (miles below outfall) : Slope (fpm) Velocity (fps) : K1 (base o, per day) : K2 (base e. oer day) : f-8Y Effluent Monthly Effluent "onthly Characteristics Average Comments Characteristics l.verage Comments �o� s 3oDs I T 30 En n. Q T"55 30 /P l Cm ', I000 10o eciz �<< M o00 00 Z 1 (0 -5 ` ig a 1 n O Comments: (� v cation O �( nf' a 'on O U pared By: Reviewed By: Date: f� � ^ . Aequest No . 305T � - ---~-----^--~-------- WASTELOAD Al LVCATION APPROVAL FOAM --~--`'`---`---~------ � � � � Facility Name TOWN OF HAVELOCK WWTP � Type of Waste DOM u�^ Status Receiving Stream EAST P|lONC Sl nCUM CAEEK Stream Class � C'SW 4� «� Subb 030410 County CAAVEN Drainage Area ( sq mi. ) � Aegional WASHINCT0N 71410 TIDAL Aequesxor Winter 7q:1.0 ( cfs ) � Date of 3OQ2 (cfs ) � Qua 1-131NW Average Flnw ( cfs > � ...................................................... ..................................... AFCOMMENPED EFFLUENT LIMITS ..... ............--.............. ...............................-..... � � SUMMEA WINTEA Wasteflow ( mgd) 1 . 5 5-Day DOD ( mg/l ) Ammonia Nitrogen < mg/l > 2 3 Dissolved Oxygen ( III g/l 6 6 TSr; ( mg/1 ) 30 3O Fecal Coliform (#/10Oml ) 1000 1000 pH ( Su> 6 . 8-9 6 8`9 --........................................................................................................... ............................. ------^`^~-----------------------^--- ...............................................................................................'~...................... COMMENTS ............................... ----------------------.............. � [ r C..l, � � ............-............ ......................................--.....................................................................................--............................................ ...............-..................................................... Aecommended Date_ ^' _ Aeviewed by \ / Tech � Support Supery Date Aegional Supery Dat.e--k�' 7f,1��7 Perwits jd, ' /rY) ,��(`�� mk� �yl, mil eoc►roq�—C- L. — � oyn_oynLs �r_►o�Gfit.P��cam/ nOn �-e&�c,�,�A��— ,��pt{o.wr_u�/1.,_(Me- 4,I i '�I , ill II 1' n, I 5 50 - I i i l y 7-Z - ��l Iro%- y,a 3� S • I ) l' I� ?1iSClIArtGER1 HAVELOCK NAME OF ESTUARY SENSITIVITY DEPTH 5 . 00 FEET WIDTH 65 . 00 FEET VOLUME t 2 . 917Ei006 CUING FEET FRESHWATER INFLOW 0 . 00 CFS WASTEWATER FLOW I 1 . 50 MGD ULT . ROD OF WASTE 33 . 00 MG/L MAX TIDAL VELOCITY 0 . 12 KNOTS CROSS-SECTION AREA 325 . 00 SQ . FT . ADVECTIVE VEL . 0 . 12 MI/DAY DISPERSION I 0 . 12 SQ . MI ./DAY I<1 2 0 . 20 PER DAY - lp-0 K2 0 . 30 PER DAY , ROD AT OUTFALL = 11 . 6633324955 MG/L . D . O . AT OUTFALL = 5 . 15411215532 MG/L MILEPOINT UPSTREAM DOD UPSTREAM D . O . 0 . 00 11 . 66 5 . 15 -0 . 10 9 . 68 5 . 27 -0 .20 8 . 03 5 . 42 MILEPOINT DOWNSTREAM DOD DOWNSTREAM DO 0 .00 11 . 66 5 . 15 0 . 10 10 . 67 5 . 09 0 . 20 9 . 76 5 . 08 0 . 30 8 . 92 5 . 10 0 . 40 8 . 16 5 . 15 0 . 50 7 . 47 5 . 21 0 . 60 6 .83 5 . 29 0 . 70 6 . 25 5 . 37 0 . 80 5 . 71 5 . 46 0 . 90 5 . 22 5 . 56 1 .00 4 . 78 5 . 65 1 . 10 4 . 37 5 . 74 1 . 20 4 . 00 5 . 82 1 . 30 3 . 66 5 . 91 1 . 40 3 . 34 5 . 99 1 . 50 3. 06 6 . 06 THE WASTELOAD ALLOCATION FOR HAVELOCK IS 33 MG/L.. DISCHA GER HAVELOCK NAME OF ESTUARY SENSITIVITY DEPTH : 5 . 00 FEET WIDTH 65 . 00 FEEL' VOLUME : 2 . 917,+006 CUBIC FEET FRESHWATER INFLOW 0 .00 CFS WASTEWATER FLOW : 1 . 50 MGD ULT . BOD OF WASTE : 18 . 00 MG/L. MAX TIDAL VELOCITY : 0 . 12 KNOTS CROSS-SECTION AREA : 325 .00 SC1 . FT . ADVECTIVE VEL. : 0 . 12 MI/DAY DISPERSION : 0 . 12 SO .MI . /DAY K1 : 0 .35 PER DAY -rP'0 K2 : 0 . 43 PER DAY rtc� BOD AT OUTFAL.L = 4 . 9432206738 MG/L . D .O . AT OUTFALL = 5 . 02312547934 MG/I_ MILEPOINT UPSTREAM BOB UPSTREAM D. O . 0 . 00 4 . 94 5 . 02 -0 . 10 3 .94 5 . 15 -0 . 20 3 . 14 5 .30 MILEP'OINT DOWNSTREAM BOD DOWNSTREAM DO 0 . 00 4 . 94 5 .02 0 . 10 4 . 35 4 . 96 0 .20 3 .82 4 . 94 0. 30 3 .36 4 . 96 0 . 40 2 . 95 5 . 01 0 . 50 2 . 60 5 , 08 0 . 60 208 5 . 17 0 . 70 2. 01 5. 26 0 . 80 1 . 76 5 . 36 0 . 90 1 , 55 5 . 46 1 . 00 1 . 36 5 . 57 1. . 10 1 . 20 5 . 67 1 .20 1 . O5 5 . 77 1 . 30 0 . 93 5 . 87 1 . 40 0 . 81 5 .96 1 , 50 0 . 72 6 . 04 THE WASTEL.OAD ALLOCATION FOR HAVELOCK I 18 MG:L 1�� C4 ��> /41- - 9, 1 z ,i NC do z 1253 �fi Iota I x 3d i �I IN-STREAM ASSESSMENT REQUEST FORM q�6 I. Facility name H q v< W H/ 7P Design flow /. 25- 0160 Subbasin og-oG_io County Crot o-em Receiving stream gs F P�`ON9 0* S/eu,,.,Classification C—Sw D II. Existing plant data time period averaged j, -- /�P6 flow O . 7 o s. g mgd BOD5 7. 6 mg/1 NH3 O.o y mg/1 DO S mg/l TSS 31 mg/l fecal coliform / 2.$ /100 ml pH 7. I $. O SU Suggested SOC limits: flow 1 . 2/5- mad BODS /J m3/1 NH3 2 mg/1 �FCe/•'/�D DO 6 mg/1 TECHNIC41 Q ��85 TSS So mg/1 RV1CeS BpgNCh fecal coliform /000 /106 ml pH —g. S SU III. Previously Approved SOC flow p mod Approximate percent domestic % Approximate percent industrial % Currently requested SOC flow D. / / S 3 S mgd percent domestic /oo % percent industrial % List industries and type of waste below: 6.�02� N �a ,it Z i Ali t ! 'h i t ,fl DIVISION OF ENVIRONMENTAL MANAGEMENT April 8, 1986 M E M O R A N D U M TO: Roger Thorpe FROM: Randy Dodd THRU: Meg Kerr 0- Steve Tedder SUBJECT: Instream Assessment : Havelock WWTP Per your request, an analysis has been performed to determine the impact the addition of 0.11535 mgd of domestic waste will have on East Prong Slocum Creek, a "C-SW" stream. At' the point of discharge, the creek is tidally influenced, therefore, a Level B estuarine analysis was conducted. Wasteload characteristics were developed based on suggested SOC limits and the average wasteflow, as provided by your office. Under present hydraulic loading, the predicted D.O. minimum is 4.16 mg/1 0.1 miles below the outfall . With the additional SOC flow, the predicted minimum is 3.85 mg/l . With the additional flow, an additional 0.2 stream miles are predicted to have D.O. concentrations below 5 mg/l . Please advise if questions. RCD:mlt cc: Bob DeWeese b M State of North Carolina Department of Natural Resources and Community Development Division of Environmental Management 512 North Salisbury Street • Raleigh, North Carolina 27611 James G. Martin, Governor R. Paul Wilms S. Thomas Rhodes, Secretary Director June 23, 1986 Mr. Ed Rexrode City of Havelock WWTP P.O. Drawer 368 Havelock, NC 28532 Dear Mr. Rexrode, I have examined effluent limitations assigned to the Havelock WWTP discharge to the E. Prong of Slocum Creek as you requested. A description of-the modeling equations and the reaction rates used for Havelock are attached. The rate coefficients are based on literature values since no water quality modeling data are available for your receiving stream. I have also attached copies of the correspondence I mentioned on the phone. The Division has predicted effluent limits of 5 or 6 mg/I BOD and 2 mg/1 NH since 1976 for flows greater than 1 mgd. Please note that5 the limits at3ached to the March 22, 1976 letter were calculated to protect a stream standard of 4 mg/l dissolved oxygen. The standard for E. Prong Slocum Creek is now 5 mg/1 , so more restrictive limits are required. I ran our desktop computer model for estuary simulations for discharges of 1 .25 mgd , 1 .5 mgd, 2.0 mgd and 2.5 mgd. The output printouts are attached for your information./As you can see, we assumed that E. Prong Slocum Creek is 5 feet deep and 65 feet wide at the discharge point. The freshwater inflow was set at 0 cfs since this is the 7 day 10 year (7Q10) low flow for this stream. We routinely run wasteload allocation models in terms of ultimate BOD. The model will predict the ultimate BOO load that can be discharged from the WWTP and protect the receiving stream's dissolved oxygen standard at 7Q10 flow conditions. We then translate the ultimate BOD into effluent limits for BOD and NH At 1 .25 mgd , 19 mg/1 of ultimate BOD will produce a DO minimum o? 4.97 m6/l . The 19 mg/1 BOD ultimate results in limits of Pollution Prevention Pays P.O. Box 27687, Raleigh, North Carolina 27611-7687 lelcphone 919-733-7015 An Equal Opportunity Affirmative Action Employer Mr. Ed Rexrode June 23, 1986 - page two - 11 mg/1 BOD and 2 mg/1 NH3 if we assume that BOO is equal to the ultimate carbonaceou5� BOD. In 1985, my staff reviewed a I�rge dataset of ultimate BOD tests. This data demonstrated that the ultimate carbonaceous BOD is at least 1'h times the five day BOD. Furthermore, we previously assumed that the ultimate NBOD was equal to 4.0 times the NH Stoichiometrically the oxygen consumed by nitrification of NH to NO3 13s 4.57 mg/l . We now use a multiplier of 4.5. Using this infor�ation , the limits at 1 .25 mgd would be 7 mg/1 BOO 5 and 2 mg/1 NH At 1 .5 mgd, the limits are 5 mg/l BOO and 2 mg/l NH with the new bredd'own of ultimate BOD.* The limits becom� more restrictive as the flows increase: 4 BOD5 and 1 NH3 at 2.0 mgd and 3 BOD5, 1 NH3 at 2.5 mgd. While reviewing the effluent limits for Havelock, I briefly scanned your self-monitoring data. The data shows both upstream and downstream. DO' s depressed below the 5 mg/1 stream standard. Values between 3.0 mg/1 and 4.5 mg/1 were measured 67% of the time in April and May of 1986 above the plant. The data also show that DO conditions are severely stressed below the plant. Measurements as low as 0.5 mg/1 (4/28/86 and 10/2/85) suggest that the plant is impacting E. Prong Slocum Creek. The Havelock WWTP provides excellent waste treatment. Your effluent BOD's are rarely above 5 mg/1 and the ammonia is consistently below 1 mg/1 . The measured dissolved oxygen condition of the E. Prong Slocum Creek suggests that either ambient conditions are low or that the stream' s assimilative capacity is depleted. The Division will be investigating this in more detail in the near future. I hope this answers your questions. Please give me a call at (919) 733-5083, if you have any additional questions. Sincerely, 4t4 Meg Kerr MK:mlt Attachments cc : Roger Thorpe Steve Tedder Jay Sauber * New Breakdown : ultimate BOD = 1 .5 (BOD 5) + 4.5 (NH3) Old Breakdown: ultimate BOD = BOO + 4 (NH3) !!;I G E R i . I - 5 N A HE OF ECTUAIZ-V E FR0igr S L,0 F"U M. F,E E ;,I T.!r I L . ;-'.' 11 5 F E E C U F. I c F.I..tw.1 7V FRE-SHWATER INFLOW 0 1011) CF.. WASTEWATER F C)W il 4,25 `-,Mall, ULY . ROD OF WAS TE 4 1.9 . 00 MG/L MAX TIDAL VELOCITY 0 . 12 KNOTS CROSS-SECTION AREA 325 , 00 _ SQ . Fl , ADVECTIVE VEL , 0 . 10 MI/DAY DISPERSION 0 . 12 so . MI. /DAY Kl 0 . 53 PER DAY _K2 0 . 44 PER :DAY ROD AT OUTFALL 3 . 6079734319 MG/L . f.., , O . AT OUTFALL '.5 . 0, 1358,159c 7,.-, M Ci,,,L M I L E PO I N T UPSTREAM ROD UPSTREAM D . O . 0 . 00 3 , 61. 5 . 01 -.0 . 10 2 . 80 5 . 13 -0 . 20 5 . 29 M.1 L E PO I N 1 DOWNSTREAM 1?0 D 'DOWNSTREAM DO 0 . 00 3 . 61 5 . 01. 0 . 10 3 . 03 4197 0 . 20 2 . 5 5 4 . off 0 . 30 2 . 14 5 . 04 0 . 40 1 . 80 5 . 13 0 . 50 1 . 52 5 . 23 0 . 60 1 ,27 5 . 35 0 . 70 1 . 07 5 . 47 0 . 80 0 . 90 5 . 50 0 . 90 0 . 76 5 . 71 1 , 60 0 : 64 5 . 83 I I 10 0 . 54 5 . 94 1 . 20 0 . 45 .6 . 04 1 . 30 0 . 38 6. 14 1 . 40 0 . 32 6 . 23 1 . 50 0 . 27 6 . 31 EUMELS!LGA mr kdvAL ff �Bo a Iviq, -/),,.5 result in U5lr71 1cl (IPL-C Ile5) L'u oia ke- D1..SCH A,CSEK � HAYELOCK Ar;ME 0�- ESTUA�l D[PTH | 5CO FE�T HIDI LJ YOLUhE 2 . 17EiCC, CU IC FEET }: SHWATER l FLOW O CFS WASTEW4TER FLOW | (�i�50.-, D, ULT ^ ROD OF WAST[ | 16 ^ 00 MG/i MAX TIDAL VELOCITY 0 ^ 12 KNOTS CROSS-SECTION AREA 325 , 00 SQ ^ FT ^ ADVECTIVE VEL , 0 , 12 MI/DAY DISPERSION �� O ^ 12 SQ ^ MI ^/DAY � � K1 - �'- �� '�� 0^ 53 _ � PERJ.AY K2 . ��` ^ ' � O ^ 44 � PER DAY ' ' 3Dlli AT OUTFALL 3 , 61732866398 MG/L . D ^ O , AT 0UTFALL 43931612O85 MG/L MILEPOINT UPSTREAM B0D UPSTREAM D . O . 0 . 00 3 ^ 62 5 ^ 04 -0 , 10 2 , 78 3 ^ 17 -0 ^ 20 2 . 13 5 ^ 34 � MILFPOlNT DOW,NSTKEAM. BOD D0WNS-,'REAM DD 0 ^ 00 3 , 62 5 ~04 0 ^ 10 3 ^ 06 4 ^ 98 0 + 20 2 ^ 59 4 ^ 93 0130 2 , 19 5 , 03 0 ^ 40 1 ^ 85 5 ^ 10 0 . 50 1 ^ 57 5 " 19 0 ^ 60 1 ^ 33 5 ^ 3O 0^ 70 1 ^ 12 . � , 41 0 ^ 80 0 . 95 5 ^ 53 ' 0'^ 90 0 , 80 5, 65 1 ; OO 0 ^ 68 5 , 76 1 ^ 10 0 , 58 5 ^ 87 1 , 20 0 ^ 49 5 ^ 97 � 1-,30 0 ^ 41 .6 , 07 1 ^ 40 0 ^ 35 6 , 16 1 ^ 50 0, 30 6 ^ 25 THE WASTELOAD ALLOCATION FOR HAVELOCK IS 16� MG/L ` . � .6^ �} �� "`' �� H4IELOCK OF EST i�R\ E Pk'ON6 SLOCUM CREE� DE�Ti1 � 5 O FE[T 1):LU8E � 2 ^ 9\7E1006 CU9I[ FEEI F8EEHI JATER lNFLOW OO CFE �ASTEWATES FLOW OO MGD ULT . BOD OF WASTE 12 , 00 MG/L MAX TIDAL VELOCITY 0 , 12 KNOTS CROSS-SECTION AREA 325 ^ 00 SQ ^ FT ^ ADVECTIVE VEL ^ 0 ^ 16 MI/DAY DISPERSION 0 ^ 12 SO. K1 �� ' � /��. �� 0 ^ 5 ` E K DAY -� ' --r � � - i�� '� -- � K2 � ' - ' - BOD AT DUTFAiL - 3 ^ 54750050426 MG/L. D . O ^ AT OUTFALL = 5 ^ 16*09506255 MG/L MILEPOINT UPSTREAM BOD UPSTREAM D . O , O ^ OO 3 ^ 55 5 , 16 ^0 , 10 2 ^ 67 5. 31 -0 , 20 2 ^ 01 5 , 50 - - --- MlLEPOINT DOWNSTREAM BOD DOWNSTREAM DO O ^ OO 3 ^ 55 5 ^ 16 0 ^ 10 3 ^ 04 5 ^ 08 0 ^ 20 2 / 60 5105 0130 2 ^ 23 5107 0 . 40 1 , 91 5 ^ 11 0 , 50 1 ^ 63 5118 ` O , 6O 1 ^40 � 5 ^ 27 ' ` 0 ^ 70 1 , 20 5 ^ 36 - 0 ,80 1 ^ 03 5 . 46 0. 90 0 ^ 88 5 ^ 57 1 ^00 ' 0 ^ 75 5 ^ 67 1 ^ 16 0 ^ 65 5 , 77 ' 1 ^ 20 0 ^ 55 5 , 87 30 0 ^ 47 5 ^ 97 �� 06 4O O 41 6 ' �^ � ^ 0 ° 35 ' 6 ^ 14 THE WASTELOAD ALLOCATION FOR HAVELOCK IS 12. MG/L. S~ _ H4YELUCK NAME OF ESTUARY E PRONG SLOCUh CC[Ek 0EFTH 5 , 00 FE0 eIVl !| 65 , 00 F[Q Y0LUME 2 . 91 ?Ef006 CUBIC FEET FRESHWATER INFLOW C ^ oo CFS WASTEWATER FLOW 2 ^ 50 MOD ULT . ROD OF WASTE 10 ^ 00 MG/L MAX TIDAL VELOCITY 0 ^ 12 KNOTS CROSS-SECTION AREA 325 ^ 00 PQ ^ FT ^ A0VECTIVE VEL ^ 0 , 20 MI/DAY `DISPERSION ' � 0 ^ 12 SQ ^ MIuDAY K1_� �_ _O ^53 PER _ DAY : � K2 � 0 ^44 PER DAY ,� ' ROD AT OUTFALL 3 ^ 60770096389 MG/L . 8 ^ 0 . AT OUTFALL = 5 ^ 23251776759 MS/L dlLEPOINT UPSTREAM BOD UPSTREAM D . O . O ^ OO 3 . 61 5 , 23 -0110 2 ^ 65 5 ^ 40 -0 ^ 20 1 ^ 95 5 , 60 � - - '----- MILEPDlNT UOWNSTREAM 0OO DOWNSTREAM DO O ^OO 3 ^ 61 5 ^ 23 0 , 10 1 , 12 5 , 12 0 , 20 2 , 70 5 ,07 0 ^ 30 2 . 34 5 ^ 06 0 ^ 40 2 ^ 03 5 ^ 08 0 , 50 1 ^ 76 5 ^ 13 6^ 80 1 ^ 52 5 ^ 19 � 0 ^ 70 1 , 32 5 ^ 27 0, 80 1 . 14 5 , 36 0 ^ 90 0^ 99 ' 5 ^ 46 1 ^ 00 Oi85 5 ^ 55 1 ,10 0 ^ 74 5 ^ 65 1 . 20 0 / 64 5 ^ 74 �1 ^ 30 0 ^55 5 . 84 1v40 0448 5 ,92 1 ,50 0 . 42 6 ^ 01 THE WASTELOAD ALLOCATION FOR HAVELOCK IS 10 MG/L. vv �� | ' � -5 i V March 22. 1976 Mr. Joseph E. Hardee Moore, Gardner 6 Associates, Inc. Greensboro, North Carolina Dear Mr. Hardee: We have attached a tabulation of the revised effluent limits for the 4voock 201 Alternatives. The limits are maxiaum monthly mean values unjess otherwise noted. The limits reflect current policies and methodologies and are consistent with the 303(e) Basin Planning Process. —` 19e have also attached a discussion and explanation of the effluent limits. Please contact Mr. R. F. McGhee of N' staff if you have any questions concerning the limits. _ W _hope-you find our information complete for your development of the velock 201 Facilities P a� Sincerely, Original Signed by L. P. BENTON, JR. L. P. Benton, Chief Water Quality Section ttachment A. C. Turnage - EFO R. F. McGhee ( H. B. DuHart C. A. Gordner-T. F. Armstrong J EFFLUENT LIMITATIONS ' _ VNI CD Y ? > f c W Q W N W O lJi E I U K �� O Wa) a) W N U J •1 lA c p F- N O J y p U p Q i e0 J m W N p= m O J C T N p s p d' d W O 'y �Ui d� ` N �zU7 0 W X G! a J (n F- I� p c] •4y to N E C' F- W U /-- •O i 4 N cn mF--0 N k/l EN c DISCHARGER - RECEIVING STREAM cfs MGD mg/1 mg/1 mg/1 mg/1 °C ft mi mg/1 ml of v SU Havelock - East Prong Slocum Creek NEUI -SW 0 0.5 46 20 7 5 29 30 200 6-9 B EU10 -SW 0 1 .0 23 11 3 5 29 30 200 5-? 11 10 -SN 0 1 .75 13 6 2 5 29 30 200 -9 9 Havelock - Slocum Creek @ Tucker Creek 1EU10 SC-SW 0 1 .75 77 20 14 5 29 30 200 6-9 u NCAS - Slocum Creek 1EU10 SC-SW 0 3.8 16 20 14 5 29 30 200 0 4 E EU10 SC-SW 0 5.5 53 20 8 5 29 30 200 5-9 3 Regional WTP - Meuse River 41EU10 SB-SH 225 1 .75 110 30 29 30 200 6-9 E Slocum Creek fuel n, ;l DATE: ,4..,. Jr- DATE RECEIVED: DATE ALLOCATION NEEDED: Prn" /-T MEMO T0: Alan Klimek T FROM: /4e(rr7 Kam-Fina n n n1 E FO SUBJECT: Effluent limits for Permit Review DISCHARGE IDENTITY: aue �v c�/L S l P COUNTY: cr",t C ' SUB-BASIN: /J�� dui RECEIVING STREAM: Easf /krona SloGuwi Cru CLASS: 7/10 MINIMUM FLOW: _(1SC�Ssfrn��cs O.O SLOPE: feet/mile ' LOCATION OF DISCHARGE: ate, &--.w.. 0/a. ,.- DESIGN CAPACITY: a . O mq 3 EFFLUENT LIMITS 1�w Parameter Limits UOD Z TKN— ^^ / KN - s �G (iW TSS b TAB' Col i form (Fecal ) ib c n� / /�/ PH - q Si k• 1�� Temperature a"."ol�<.e, oXyi�� REMARKS: DIVISION OF ENVIRONMENTAL MANAGEMENT October 20, 1982 MEMORANDUM TO: Randy Williams, Supervisor Waste Load Allocation Unit FROM: Jim Mulligan, Regional Supervisor Washington Regional Office SUBJECT: Havelock Wastewater Treatment Plant Craven County After conferring several times with the city to consider their immediate, short and long term future wastewater treatment needs, it is obvious that the review of the alternatives would benefit greatly from your evaluation. The present IMGD WTP was de- signed and constructed to meet effluent limits of BOD5 = 5 mg/l and NH3 = 2 mg/l. These limits were relaxed. to a BOD5 of. 11 mg/l and NH3 of 3 mg/l which are contained in the present NPDES permit. The system is rapidly approaching hydraulic load (in fact, monthly average flows were over 1 MGD twice in 1982) , more flow has been permitted already (but not yet tributary to the system) and still more is proposed. Please find attached a table showing the WTP performance for the last year, with an average effluent BOD5 of 2.7 mg/l, NH3 of less than 0.46 mg/l and TSS of 14 mg/l. The city, their engineer (Moore-Gardner & Assoc.) and this office are presently con- sidering a number of possible courses of action: a.) an S.O.C. to increase the allowed flow to accommodate immediate needs; b.) the alteration of the stated design flow of the facilities in the NPDES permit (and- the limits) to meet short term future needs; and c.) the site, location and type of wastewater treatment technology necessary to meet the city's needs for the long term future. In order to facilitate the consideration of these alternatives, a determination of the waste load allocation for higher flows at the present point of discharge is needed. The S.O.C. will have to be a complete package in Raleigh by Wednesday, October 27, 1982 in order to be considered by the EMC in November. In order to prevent the necessity for another S.O.C. , the permit alteration will have to be made by the end of the year. It is therefore essential to have allocations determined immediately for the following flows: 1. 1, 1.2, 1.3, 1.4 and 1.5 MGD. The two lower flows are likely candidate6 for inclusion in the S.O.C. while the higher ones are design flows to be considered for possible NPDES amendment. Please thank Meg Kerr for relaying this information to you earlier as a result of an October 15, 1982 telephone conversation with me. JM/cm cc: Bill Mills Ted Mew Havelock WTP Self Monitoring Data (MGD) (mg/1) (mg/1) (mg/1) Date Flow BOD TSS NH3 as N Sept. 1981 0.795 2.7 10 <0. 1 Oct. 0. 733 2. 3 14 0.8 Nov. 0. 718 1.7 13 <0. 1 Dec. 0. 799 2.5 10 <0. 1 Jan. 1982 1.008 3.6 9 1 .7 Feb. 1.019 3.3 20 < 1 March 0.961 2.6 13 <1 April 0. 756 2.3 13 0.06 May 0.697 2.5 14 0.04 June 0.743 3.0 16 0. 12 July 0.818 2.9 17 0.41 August 0.744 3.2 14 0. 15 Ate. 0.816 MGD 2. 7 mg/1 14 mg/1 <0.46 Model Parameters for Havelock Q = upstream flow + waste flow = O cfs + waste flow in cfs width = 65 ft depth = 5 ft K1 = 0.53 per day K2 = 0.44 per day dispersion = E = 0. 12 mil/d The dissolved oxygen in the estuary before the waste impacts it is assumed to be 7 mg/l . waste dissolved -oxygen is 5 mg/l BASIC LAKE / ESTUARY MODEL DERIVATION * 1 . Assumptions A. One dimensional system 1 . Only looking at longitudinal gradients 2. Model describes variations in water quality over a sequence of tidal cycles , not within cycle changes B. Steady-state (rate of accumulation = 0) C. Only point-sources of pollution, no distributed loads entering the system D. Constant flow, area, dispersion, decay rates I1 . Continuity Equation : BOD in an estuary / lake A. Accumulation = amount in - amount out = transport due to advection + transport due to dispersion + sources / sinks B. At steady state accumulation = 0 C. Mathematically, O = - Q ds + E 7 2 _ K1S A dx dx where Q = flow (cfs) A = cross sectional area (ft2) S = concentration of BOD (mg/1 ) E = dispersion coefficient (ft2/d) K1= BOD decay rate (per day) x = distance (ft) * Reference: Thomann, Robert V. Systems Analysis and Water Quality Management. McGraw-Hill Book Company, 1972. pp. 123 - 146. -2- D. Solutions S = So exp (j1 X) for X < 0 = So exp (j2 X) for X > 0 where j 1 = U [ 1 + (1 + 41 E ) Y, 2E U 2E U W So = Q ( 1 + 4 K E ) Y2 U U = Q III . Continuity equation : DO in an estuary / lake A. Coupled to BOD solution 2 0 = - Q � + E � - K2 S2 + K1 S1 A dx dx where S2 = DO deficit (saturation DO - actual DO) K2 = reaeration rate B. Solutions S2 = K1- ( W ) ( E1 - E2 ) for X < 0 K2-K1 Q M1 M2 S2 = K1— ( W ) ( E3 - 1 ) for X > 0 K2-K1 Q M1 M2 3 where E1 = exp ( u x ( 1 + M1 ) ) E2 = exp ( u x ( 1 + M2 ) ) E3 = exp ( U x ( 1 - M1 ) ) ZE E4 = exp ( a x ( 1 - M2 ) ) M2 = ( ( 1 + 4 K 2 E ) / U2 ) Y,