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Home My WebLink AboutNC0026646_Environmental Assessment_19940921NPDES DOCUHENT SCANNING COVER SHEET NPDES Permit: NC0026646 Pilot Mountain WWTP Document Type: Permit Issuance Wasteload Allocation Authorization to Construct (AtC) Permit Modification Complete File - Historical Engineering Alternatives (EAA) Correspondence Owner Name Change Instream Assessment (67b) Speculative Limits Environmental Assessment (EA) , Document Date: September 21, 1994 This document is printed on reuse paper - ignore any content on the re.werse side DIVISION OF ENVIRONMENTAL MANAGEMENT September 21, 1994 MEMORANDUM TO: Monica Swihart FROM: Michelle Wilson/M/11'J THRU: Ruth Swanek ";;c a Carla Sanderson SUBJECT: Revised after comments Pilot Mountain's 201 Facility Plan Revision Project # 658 Surry County Yadkin 03-07-03 The Instream Assessment Unit has reviewed the revised 201 Facilities Plan prepared by William C. Piver & Associates. This Plan includes the relocation of the Town of Pilot Mountain's Wastewater Treatment Plant outfall to the Ararat River. Answers to comments clarify the reason for this EA which is for the relocation only, not the expansion. If this is the case, the revised EA was found to thoroughly and clearly address the concerns raised in our August 28 memorandum regarding the original revision to the 201 facility plan. The Town is aware that the effluent limits which will apply for the Ararat River may become more stringent in the future. These more stringent limits will come into effect when the facility decides to expand to 3.0 mgd at their new outfall location. The current USGS stream flows (listed below) will be used to determine the limits for expansion. The existing permit limits at 3.0 mgd will have to be modified before the facility expands to include the limits necessary to protect the water quality in the Ararat River. S7Q10 = 70 cfs W7Q10 = 100 30Q2 = 166 cfs QA = 318 cfs MEMO TO: /i./ ; y; lcwiPMOl LCar� SUBJECT: DATE- //�1/�1 Panl Pi4A-fey /C; M eA / Z D.1-1. .2Y7/y/ Z / .ereevG r - u/aF.f � .. •_ s7o rw = 5 '� Z (/J 30a2= 131cJ -QL = 11gch 56.6 (k7 (eviod° / fo-1/ I reLei•--6 .7.t 0 //3 oc� Z A. 70 /0, ki/73662. Qr� : 3/Y WV - a3, From. /QV bil6.-6\ tst-kra I ---a-{- kive_J-- L es (S F"/0(4) it: ��;., ,-f-� 0a-/ ( c� �50 (6�Stid an /gi(o3- m5d 'a,) � z.... ' r a /gra rA4 /Q' JeX @ 4rtr M23/viflit ; a --7Q IO = 6-2, G)s 30Q.2. /37 cm, - f/e-c-5e_ -710 7BCD cis nt, cycled Paper USGS weighted low flow estimate procedure Facility[Pilot Mtn WWTP NPDES # INC0026646.I StreamLArarat Region DA LFPR s7Q10_LFPR DAnew MAR QA eq STEP 1 HA10 NOTE: procedure applies for regions HA3, HA5, 231 sq mile HA9, and HA10, else see flow SOP ..NI..57:?._.._.. cfs _ 287 1.2 344.40 sq mile cfs/sq mile cfs calculate drainage area ratio RATIO = new drainage area drainage area at gage IF 0.25 < RATIO < 4, CONTINUE to STEP 2, ELSE too far from gage OK, do STEP 2 now! STEP 2 determine weight of gage (weight_LFPR) A. RATIO < 1 weight i2iiSI 0 1 s 1 0.25 STEP 3 HA3 HA5 HA9 HA10 STEP 4 weight = 0.92 B. RATIO > 1 weight Lati4 0 1 0.92 1.24 1 4 calculate 7Q10 EQ using regional equation 66.37 3.93 3.93 56.59 cfs cfs cfs cfs 7Q10EQ= calculate 7010 yield using weighted equation 56.59 7Q10yield = [weight LFPR * 7010 LFPR] + [weight EQ * 7010 EQ] cfs DA LFPR DA new yield = 0.23 STEP 5 calculate s7Q10 7010 = 7Q10yield * DA new summer 7010 = 69.90 cfs 1 24242424j + 0.02 = 0.24 cfs/sq mile USGS weighted low flow estimate procedure FacilityLPilot Mtn WWTP NPDES # iNC00266461 Stream':Ararat Region _.._ HA10_._ NOTE: procedure applies for regions HA3, HA5, DA LFPR 231 sq mile HA9, and HA10, else see flow SOP w7010_LFPR 100 cfs DA new MAR QA eq STEP 1 287 MOM INOMO•1111 1.2 344.40 sq mile cfs/sq mile cfs calculate drainage area ratio RATIO = new drainage area drainage area at gage IF 0.25 < RATIO < 4, CONTINUE to STEP 2, ELSE too far from gage OK, do STEP 2 now! STEP 2 determine weight of gage (weight_LFPR) A. RATIO < 1 B. RATIO > 1 weight l 0 1 0 1 #VALUED, see B 1 [OE921 "�__ 1.24 1 4 f 1 0.25 weight = 0.92 STEP 3 calculate 7010_EQ using regional equation HA3 HA5 HA9 HA10 STEP 4 128.58 23.61 23.61 81.86 cfs cfs cfs cfs 7Q10 EQ= calculate 7010 yield using weighted equation 81.86 cfs/sq mile 7Q10yield = [weight_LFPR * 7010 LFPR] + [weight_EQ * 7Q10 EQ] DA LFPR DA_new yield = 0.40 STEP 5 calculate w7Q10 7010 = 7010yield * DA_new winter 7010 = 120.82 cfs r1.?42421a1 + 0.02 = 0.42 cfs/mile o USGS weighted low flow estimate procedure FacilityLPilot Mtn WWTP NPDES # Region DA LFPR 3002 LFPR DA_new MAR QA eq STEP 1 1 NC0026646 i Stream Ararat _ HA10 NOTE: procedure applies for regions HA3, HA5, �� 231 �« -. sq mile HA9, and HA10, else see flow SOP 137 cfs 1.2 344.40 sq mile cfs/sq mile cfs calculate drainage area ratio RATIO = new drainage area drainage area at gage IF 0.25 < RATIO < 4, CONTINUE to STEP 2, ELSE too far from gage OK, do STEP 2 now! STEP 2 determine weight of gage (weight_LFPR) A. RATIO < 1 B. RATIO > 1 weight L8ti4 weight ratta ritilAilill 0 1 0 1 see B r 0.92 ) 1.24 0.25 1 4 1 weight = 0.92 STEP 3 calculate 3002_EQ using regional equation HA3 HA5 HA9 HA1 0 146.59 34.65 34.65 118.47 cfs cfs cfs cfs 30Q2 EQ = STEP 4 calculate 3002 yield using weighted equation 1.24242 24j 118.47 cfs/sq mile 3002yield = [weight_LFPR * 3002 LFPR] + [weight_EQ * 3002 EQ] DA LFPR DA new yield = 0.55 STEP 5 calculate 30Q2 3002 = 3002yield * DA new 3002 = 166.03 cfs + 0.03 - 0.58 cfs/sq mile DIVISION OF ENVIRONMENTAL MANAGEMENT August 26, 1994 MEMORANDUM T0: Monica Swihart FROM: Michelle Wilson 1 THRU: Ruth Swanek QC Carla Sanderson SUBJECT: Pilot Mountain's 201 Facility Plan Revision Project # 658 Surry County Yadkin 03-07-03 The Instream Assessment Unit has reviewed the revision to the Town of Pilot Mountain 201 Facilities Plan. The Town of Pilot Mountain should consider the parameters which will be effluent limited at the new location. The Ararat River is listed as an impaired river based on biological data. In addition, instream data shows various substandard dissolved oxygen values. Evidence of Ararat River not supporting its use has prompted the Division to consider developing a calibrated model for the river. The results of the model will be used to determine allowable concentrations of oxygen - consuming parameters needed for the discharge. Furthermore, reevaluation of the stream flows using USGS current low -flow report produced lower statistics which will result in immediate changes in effluent limits for ammonia and toxicants including toxicity limits. To protect against instream Ammonia toxicity in the Ararat River the NPDES permit will include a NH3N limit of 20 mg/1 for 1.5 mgd and 10 mg/1 for 3.0 mgd. The instream waste concentration (IWC) has also changed due to the updated flows. The summer IWC in the Ararat River is 4% at 1.5 mgd and 8% at 3.0 mgd. Additional limits for metals and toxicants should be evaluated before the final permit is issued for this facility relocation to the Ararat River and expansion from 1.5 mgd to 3.0 mgd. (i.e. limits recommended as a result of the 1992 Waste Load Allocation will need to be modified to reflect these changes.) b1 SkJ-1 bel-werri01 rr re (oeu,l,v, Due to resource constraints at this time, the calibrated model for the Ararat River may not be completed before the relocation . and expansion; therefore, the facility should be informed that additional changes for oxygen consuming wastes may change after model completion. The town should consider the possibility of meeting different oxygen consuming parameters when evaluating their need for a plant upgrade and/or modification. In addition, Larry Ausley from the aquatic toxicity unit reviewed Pilot Mountain's WWTP file. The last toxicity reduction work was reported in 1989 and was geared specifically toward treatability. After looking at the toxicity data, it is not apparent that the facility has made any significant progress toward toxicity reduction nor is there a currently active toxicity reduction plan in effect. Page 1 Note for Michelle Wilson From: Larry Ausley Date: Wed, Aug 24, 1994 11:22 AM Subject: Pilot Mtn. To: Michelle Wilson I've looked through our files on the Pilot Mtn. WWTP. The last toxicity reduction work I can locate was reported in 1989 and was geared specifically toward treatability. Looking at the toxicity data, it is not apparent that the facility has made any significant progress toward toxicity reduction nor is their a currently active toxicity reduction plan in effect, of which we are aware. USGS weighted !ow flow estimate procedure Facility(Pilot Mtn WWTP NPDES # 1NC0026646 1 Stream':Ararat Region DA LFPR s7Q10_LFPR DA new MAR QA eq STEP 1 HA10 0 sq mile 0 cfs 1.2 344.40 sq mile cfs/sq mile cfs calculate drainage area ratio NOTE: procedure applies for regions HA3, HA5, HA9, and HA10, else see flow SOP RATIO = new drainage area drainage area at gage IF 0.25 < RATIO < 4, CONTINUE to STEP 2, ELSE too far from gage #DIV/0! STEP 2 determine weight of gage (weight_LFPR) A. RATIO < 1 B. RATIO > 1 weal ratiQ weight ratk 0 _ 1 riiiiiii05.1 0 1 1f.... #DIV/0! #DIV/0! #DIV/0! 1 4 1 0.25 STEP 3 HA3 HA5 HA9 HA10 STEP 4 weight = #DIV/0! calculate 7010_EQ using regional equation 66.37 3.93 3.93 56.59 cfs cfs cfs cfs 7Q10 EO= calculate 7010 yield using weighted equation 56.59 7Q10yield = [weight_LFPR * 7010 LFPR] + [weight EQ * 7Q10 EQ] cfs DA LFPR DA new #DIV/O1,J yield = #DIV/0! + #DIV/0! = #DIV/01 cfs/sq mile STEP 5 calculate s7Q10 7010 = 7Q10yield * DA_new summer 7010 = #DIV/0! cfs USGS weighted low flow estimate procedure FacilitylPilot Mtn WWTP NPDES # INC0026646 J Stream'Ararat Region DA LFPR w7010_LFPR DA new MAR QA_eq STEP 1 1 HA10 _.._.._..0-.._.-.. sq mile 0 cfs 1.2� 344.40 sq mile cfs/sq mile cfs calculate drainage area ratio NOTE: procedure applies for regions HA3, HA5, HA9, and HA10, else see flow SOP RATIO = new drainage area drainage area at gage IF 0.25 < RATIO < 4, CONTINUE to STEP 2, ELSE too far from gage #DIV/0! STEP 2 determine weight of gage (weight_LFPR) A. RATIO < 1 B. RATIO > 1 weight IdtIQ weight talk/ 0 1 0 1 fiii�Ii #DIW01 I #DIV/01 #DIV/01 1 0.25 1 4 STEP 3 HA3 HA5 HA9 HA10 STEP 4 weight = #DIV/0! calculate 7010_EQ using regional equation 128.58 23.61 23.61 81.86 cfs cfs cfs cfs 7010_EQ = calculate 7Q10 yield using weighted equation 81.86 cfs/sq mile 7Q10yield = [weight_LFPR * 7010 LFPR] + [weight EQ * 7010_EQ] DA_LFPR DA new #DIV/OI yield = #DIV/0! + #DIV/01 = #DIV/01 cfs/mile STEP 5 calculate w7010 7010 = 7Q10yield * DA new winter 7010 = #DIV/0! cfs USGS weighted low flow estimate procedure Facility(Pilot Mtn WWTP NPDES # Region DA LFPR 3002_LFPR DA new MAR QA eq STEP 1 _.._ HA10 __ 0 sq mile 0 cfs 287 344.40 sq mile cfs/sq mile cfs calculate drainage area ratio I NC0026646 StreamLArarat M,_.___ NOTE: procedure applies for regions HA3, HA5, HA9, and HA10, else see flow SOP RATIO = new drainage area drainage area at gage IF 0.25 < RATIO < 4, CONTINUE to STEP 2, ELSE too far from gage #DIV/0! STEP 2 determine weight of gage (weight_LFPR) A. RATIO < 1 B. RATIO > 1 weight Latig weight Wig 0 1 0 1 #DIV/O! #DIV/0! 1 1.-iiiiCiiiii-1 #DIV/0! 1 0.25 1 4 weight = #DIV/01 STEP 3 calculate 3002_EQ using regional equation HA3 HA5 HA9 HA10 146.59 34.65 34.65 118.47 cfs cfs cfs cfs 3002_EQ = STEP 4 calculate 3002 yield using weighted equation .- #DIV/01 118.47 cfs/sq mile 3002yield = [weight LFPR * 30Q2 LFPR] + [weight_EQ * 3002 EQ] DA LFPR DA new yield = #DIV/01 + #DIV/01 = #DIV/01 cfs/sq mile STEP 5 calculate 3002 \--NoiN o n off, 3002 = 3002yield DA new SktAtIN- J ot( 14' 601 3002 = #DIV/01 cfs p\A\.61\ ')\44 3 A,.. Q., s's'''v Bear Wallow Valley Mobile Home Park NC0076082 Pilot Mountain WWTP Ararat River Residual Chlorine 7Q10 (CFS) DESIGN FLOW (MGD) DESIGN FLOW (CFS) STREAM STD (UG/L) UPS BACKGROUND LEVEL (UG/L) IWC (%) Allowable Concentration (ug/i) Fecal limit Ratio of 24.3 :1 N00026646 Ammonia as NH3 (summer) 56.6 7010 (CFS) 1.5 DESIGN FLOW (MGD) 2.325 DESIGN FLOW (CFS) 17.0 STREAM STD (MG/L) 0 UPS BACKGROUND LEVEL (MG/L) 3.9 % IWC (%) 431 Allowable Concentration (mg/1) Ammonia as NH3 (winter) 7010 (CFS) 200/100mI DESIGN FLOW (MGD) DESIGN FLOW (CFS) STREAM STD (MG/L) UPS BACKGROUND LEVEL (MG/L) IWC (%) Allowable Concentration (mg/1) 56.6 1.5 2.325 1.0 0.22 3.9 % 20 81.9 1.5 2.325 1.8 0.22 2.8 % 57 Bear Wallow Valley Mobile Home Park NC0076082 Pilot Mountain WWTP Ararat River Residual Chlorine 7010 (CFS) DESIGN FLOW (MGD) DESIGN FLOW (CFS) STREAM STD (UG/L) UPS BACKGROUND LEVEL (UG/L) IWC (%) Allowable Concentration (ug/1) Fecal Umlt Ratio of 12.2 :1 NC0026646 56.6 3 4.65 17.0 0 7.6% 224 Ammonia as NH3 (summer) 7Q10 (CFS) DESIGN FLOW (MGD) DESIGN FLOW (CFS) STREAM STD (MG/L) UPS BACKGROUND LEVEL (MG/L) IWC (%) Allowable Concentration (mg/I) Ammonia as NH3 (winter) 7Q10 (CFS) 200/100m1 DESIGN FLOW (MGD) DESIGN FLOW (CFS) STREAM STD (MG/L) UPS BACKGROUND LEVEL (MG/L) IWC (%) Allowable Concentration (mg/1) 56.6 3 4.65 1.0 0.22 7.6 % 10 81.9 3 4.65 1.8 0.22 5.4 % 30 Orl Natural Parameter Air Quality Noise Odor Topography Geology Soils Plants Animals Littoral Zone Physical Biological Water Physical Biological ZDi I aL f/i7 /7/ kl /2-d TABLE 6.26 PRIMARY IMPACT SUMMARY U1 t ARY �,�' EXISPISr`/. t rA ids✓ PC-1 PC-2 HC-1 HC-2 HC-3 TC-1 TC-2 LA Quality of Life Parameter Land. Use Archeological, Historical Cultural & Recreational Transportation Relocation Community Services Taxes and Capital Costs Resource Use Total for Natural Parameter Total for Quality of Life Parameter Total for Primary Impact +2 +1 +1 +1 +2 +1 +1 +1 -al Parameter -2 w•sphere -2 d -2 igysical -2 biological -2 'floral Zone -2 ihysical -2 Biological -2 ter Physical +2 biological +: ity of Life P +2 +1 +1 +1 graphy and +2 +1 +1 +1 + d Use geological, lecreational sportation urce Use -1 -1 0 -1 -1 -1 -1 -nity Servi •• s and Capit +1 +2 +1 +1 +1 +2 +2 0 0 0 0 0 0 0 p 0 0 0 0 0 0 for Seconda -1 0 -1 -1 -1 0 0 -2 -2 -2 -2 -2 -1 -2 -1 0 -1 -1 -1 0 0 +2 +2 +2 +2 +2 +2 +2 +2 -2 +2 +2 -2 -2 +2 +2 -`I -4 -1 -3 -4 -4 0 -1 -6 -1 -1 -6 -6 +2 +1 -1: for HC-1A TABLE 6.27 SECONDARY IMPACT SUMMARY Alternative 1) TC-2 LA-:. L`�X,sl-'rt 5,2e /I VGr[J �� CG _-al Parameter Significance PC-1 PC-2 HC-1 HC-2 HC-3 TC-1 TC-2 LA-4 - 1 -2 •,; sphere 1 +1 +1 +1 +1 +1 +1 +1 +1 - 1 -2 -'_ +1 -2 F ysical 1 +1 +1 +1 +1 +1 +1 +1 +1 -1 -2 !iological 1 +1 +1 +1 +1 +1 +1 +1 +1 -1 -2 .:::oral Zone - 1 -2 ?'ysical 1 +1 +1 +1 +1 +1 +1 +1 +1 - 1 -2 :iological 1 +1 +1 +1 +1 +1 +1 +1 +1 - 1 -2 :er F:,ysical 1 +1 +1 +1 +1 +1 +1 +1 +1 +2 +2 :iological 1 +1 +1 +1 +1 +1 +1 +1 +1 +2 +2 :::y of Life Parameter +2 +. :iraphy and Economics 1 +2 +2 +2 +2 +2 +2 +2 +2 +2 +2 • Use 1 0 0 0 0 0 0 0 0 •theological, Cultural, :creational 1 0 0 0 0 0 0 0 0 :_-sportation 1 -1 -2 0 -2 -2 -1 -2 -1 ::urce Use 1 -1 0 -1 -1 -1 0 0 -2 - 1 -2 =unity Services 1 0 0 0 0 0 0 0 0 ::es and Capital Cost 1 0 0 0 0 0 0 0 0 +2 +2 0 0 0 0 1 for Secondary Impacts +7 +7 +8 +6 +6 +8 +7 +6 0 -2 - 2 -1 0 -� for HC-1A WHOLE EFFLUENT TOXICITY TESTING 0[SELF-MONITORING SUMMARY] Tue, Jul 19, 1994 FACILITY REQUIREMENT I'@PIECOSTAL HOLINESS CHURCH PERM CI IR LIM:31% (GRAB) NC00468091V01 Begin:3/1/91 Frequency: Q P/F 6 FEB MAY AUG NOV NonComp: County:GU1LRRD Region: WSRO Subbasin:CPFOI PF: 0.02 Special 7Q10: 0.07 IWC(%):30.6 Onlcr. YEAR JAN 90-.01 - 92 - 93 •- 94 -- FEB MAR API? MAY JI1N 1111. AUG SEP OCT NOV H - - - - - -- - - - PASS N1 - - H - PASS Ni Ni PERDUE INC. LEWISTON PERM: 4811R LC50 AC LIM 42% NC0028835/001 Begin:11/1/92 Frequency: Q A OCT JAN APR JUL NonComp:SINGLE County: BERTIE Region: WARO Subbasin: ROA08 PF: 3.0 Special 7QI0:0.00 IWC(%):100.00 Order. Y 90 NONE 91 NONE' 92 NONE' 93 >90.0' 94 >90.0' - -- - -- - - -- - - - NONE NONE' >90.0' >90.0' >90.0' - - - -- - - -- - - NONE' NONE' >90.0' >90.0' - - - - -- - - - LATE NONE' >90.0' >90.0' NONE' - - - - - - - • PHIBRO ENERGY USA,WCJSELMA PERM:24 HR LC50 AC MONIT EPIS FTHD (GRAB) 90 - - - - - - - - - - - - NC0076457/001 Begin:8/1/93 Frequency: 3 OWD/A NonComp: 91 90' 11.9' - >90,60' - - - - - - County:JOHNSTON Region: RRO Subbasin: NEU02 92 - - - - - - - - -- - - - PF: VAR Special 93 - - - -- - - .-. >1001 - - •- 7Q10:0.0 IWC(%):100.0 Orden 94 - - - - - PHILLIPS PIPE LINE CO. PERM: 24HR P/P AC MONIT EPIS FTHD (GRAB) 90 NC0032875/002 Bcgin:7/1/94 Frequency: 5OWD/A NonComp: 91 County:JOHNSTON Region: RRO Subbasin: NEU02 92 PF: VAR Special 93 7Q10: 0.0 IWC(%):90er. 94 PHILLIPS PIPELINE CO. PERM: 24 HR LC50 AC MONIT EPIS F711D (GRAB) 90 NC0032875/001 Begin:7/1/94 Frequcncy:.5OWD/A NonComp: 91 County:JOHNSTON Region: RRO Subbasin: NE1.102 92 PP: N/A Special 93 7Q10: 0.0 IWC(%):100.0 Order 04 PHILLIPS PIPELINE CO.00I&002 PERM: 24 HR AC MON1T EPIS FIHID LC50 (GRAB) . 90 - - - - - - - - - -- - - NC0032891/001 Begin:4/1/93 Fnxlucncy:5OWD/A NonComp: 91 --- - - - - - -- - - -- -- -- County: MECKLD1BURG Region: MRO • Subbasin: CTB34 02 -- -- -- - - - - - - - -- PF: VAR Special 03 ... -. ... - -- .- ... 32.68f ••- -- 40.611 >1001 7Q10: 0.0 IWC(%): 100.0 Orden 04 57.341 - 39.53f -- - I'll ILLIPS PIPELINE CO. 003 PERM:48HR AC MONIT EPIS 00 - - - - •- - - - - - - •- NC0032883/003 Begin:1/3/89 Ftequency:5OWD NonComp: 91 - - - 18.5' 28 - - - -- - -- •- County:GUILFORD Region: WSRO Subbasin:CP1708 92 84 - - - - - - - - - - -- PF: Special • - 93 - - - - - - - - - - - - -- 7Q10: 1WC(%):NA Order: ._ . _ _.. 94 .- - - -- - I'IIILLIPS PIPELINE C0.001,002 PERM: 4811R AC MONIT EPIS 90 - - - - - - - - - - - -- NC0032883/001 Begirt:1/3/89 . Frequency: 5OWD NonComp: 91 - - -- 9.50' 36 - -- - - -- --- •- County:GUU.I ?RD Region:WSRO Subbasin:CPF08 92 28 - - -- - - -- - - -•- PF: Special . .J, 93 - - - - - - .-. - -. - __ - 7Q10:0.00 IWC(%):NA Order. / 94 - , - - - I'IIILLIPS PLATING CO.. PERM AC LIM:NO SIGN MORT(2411R PTHD) • Y 90 NR NI FAILI N9 - PASS? -• - PASS? -- • -- PASSI NC0001881/001 Begin: I1/1/89 Fsquency: Q P/F . A MAR JUN SEP DEC NonComp: 91 - - . Na PASS - Nl -- - FAIL? - -- ;BASSI County:CRAVEN Region:WARO Subbasin:NEU10 92 - PASSI .- - PASS? - - PASS? - - PASS?' PF:0.10. Special 93 - - PASSI - PASSI - - PASSI - - PASS? 7Q10: TIDAL IWC(%):NA Order. 94 - - PASSI - - PILOT MOUNTAIN WWTP PERM C71R LIM:90%, 5% tiP EXP & R ILOC, 3% @ RELOC Y 90 F.F FAIL FAIL FAIL' : )AIL N3 FAIL FAIL FAIL FAIL FAIL AIL NC0026646J001 Begin:3/I/93 Frequency: Q P/F A JUL OCT JAN APR NonComp:SINGLE 91 FAIL FAIL FAIL 17.7 - - <12.5 - - <12.5 - - County:SURRY Region:WSRO Subbasin:YADO3 92 61.2 - - 61.0 - - 35.0 - - 61.0 - -- PP: 1.5 Special SOC:9/7/93-3/1/96 MONIT Q ChV (100.50.25,10,5) 03 61.0 - - 21.0 21.0 - NR/FAIL FAIL FAIL 71.0 - -- 7QI0:0.153 IWC(%):93.82 Order 94 35.3 - - 35.0 - 0 2 consecutive failures = significant noncompliance Y Pre 1990 Data Available LEGEND: PERM = Permit Requirement LET = Administrative Letter - Target Frequency = Monitoring frequency: Q. Quanaly: M- Monthly; BM- Bimonddy: SA- Semiannually; A- Annually; OWD- Only when discharging: D- Discontinued monitoring requirement; IS- Conducting independent study Begin = First month required 7Q10 a Receiving stream low flow criterion (cfa) A = quarterly numitnring inerenscs to monthly upon single failure Months that testing must occur - ex. JAN,APR.JU1..O(-f NonComp = Current Compliance Requirement PF= Permitted (low (MGD) IWC%= Instrean waste concenration P/F = Pass/Fail chronic test AC = Acute CIIR = Chronic Data Notation: f . Fathead Minnow: • - Ceriodaohnia sp.: my - Mvsid shrimp: ChV - Chronic value: P - Mortality of stated pereenIagc m Richest concentration: at - Performed by DI1M An Tos Group: bt • Dad test Reporting Notation: - = Data not required: NR • Not reported; ( ) - Beginning of Quarter Facility Activity Status: I - Inactive. N - Newly Issucd(fo construct); 11 - Active but not discharging; 1-More data available for month in question SIG = ORC signature needed 39 A r William C. Piver & Associates was authorized to evaluate the Town's most cost effective, lona term discharge location for its wastewater treatment plant's treated effluent. The study generated and evaluated the different options available to the Town for upgrading the WWTP and/or relocating the wastewater treatment plant's treated discharge from Heatherly Creek to a stream with more favorable effluent limits. The Ararat River discharge option was one of the options evaluated. When the expense of further upgrades at the WWTP and their operating. costs .were included in the evaluation, the Ararat discharge option was deemed the most cost effective. RECOMMENDATION: 1. The Town should use this report as the basis for an application for an "Authorization - to -Construct" a new wastewater treatment plant discharge point on the Ararat River. 2 The Town should authorize the Engineer to initiate a search for funding for the project based on the projected construction budget. Revision to the Town of Pilot Mountain 201 Facilities Plan %June 30, 1994 SUMMARY: The Pilot Mountain Wastewater Treatment Plant ( WWTP) presently discharges its treated effluent into Heatherly Creek. The permitted capacity of the WWTP is 1.5 mgd, a flow which amounts to approximately 94% of Heatherly Creek's total stream flow during 7010 low flow conditions. Because the plant's discharge constitutes almost all of the stream's flow under dry conditions, the State's Division of Environmental Management [D.E.M.] has imposed stringent effluent limits on the plant's discharge to protect the environment Under today's ever increasing regulatory climate the Town cannot reasonably anticipate any lessoning of these effluent limits. They may, in fact, become even more stringent in the future. Although the existing WWTP was constructed in 1985 based upon tree recommendation of the Town's 1978 Facilities Plan and has had process modifications and upgrades as recently as this year, the Town is presently under a Special Order of Consent (SOC) due to continuing . toxicity and temperature problems at the present discharge point on Heatherly Creek. The ed‘ h• 6t7 available solutions to the toxicity and temperature problems appear to he further upgrades at z v\C>'R the WWTP, a relocation of the discharge point to a higher flow receiving stream which can tolerate more waste discharge or a combination of the two. G CONCLUSION. -� ��= Cr ems,. CURRENT SITUATION: Collection System - The Town is in the process of implementing collection system extensions as recommended in the 201 Facilities Plan. There have been no changes in the original assumptions or projections nor are any major deviations anticipated. Waste Water Treatment Plant - The recommended plan of action in the 1978 201 Facilities Plan for Pilot Mountain was to construct an Oxidation Ditch style treatment facility followed by final clarification on Heatherly Creek, which was to continue to be the receiving stream for the plant's treated effluent. The construction of this facility was completed in August of !985. However, problems soon arose with some of the innovative technology utilized in the new facility and modifications and upgrades were authorized and funded to improve the plant's aeration and sludge dewatering capabilities. These modifications and upgrades are presently under construction. Population - The Town's present population is 1 181 according to the Piedmont Triad Council of Government and confirmed by the Town. The Town has experienced no major demographic changes from those anticipated in the 201 Facilities Plan nor are any anticipated. infiltration/Inflow - The level of infiltration/inflow calculated in the 201 Facilities Plan was 0.052 MGD which was found to be acceptable for a system the size of Pilot Mountain's. No significant change in this quantity of flow has been observed and all new sewer extensions now have to meet a minimum infiltration rate of 100 gallons/day/inch/mile which should preclude future infiltration/inflow problems. Breakdown of Flows - Based on current billing records the existing flows can be categorized as follows: Source Flow (MOD) Residential 0 080 Commercial/Institutional 0.042 Existing Industrial 1.010 infiltration/Inflow 0.052 Total Present Flow 1.184 EFFLUENT LIMITS/NPDES PERMIT STATUS: The current NPDES PERMIT (NC0026646) for the Town's WWTP was issued February 15, 1993 and expires at midnight on January 31, 1998. This permit allows for an expansion of the existing facility to 3.0 MUD and relocation of the outfall to the Ararat River. A copy of this permit is located in the Appendix. FUTURE SITUATION: Population Projections - The original 201 Facilities Plan population projection of 1 ,440 for the year 2000 by the Piedmont Triad Council of Governments appears reliable. Flow Projections - The 201 Facilities Plan flow projections have been accurate to date and continue to be relied on. These are: Source Flow (MGD) Residential 0.080 Commercial/Institutional 0,042 Subtotal 0.122 Existing Industrial 0.775 Subtotal 0.897 Specified Industrial Reserve 0.090 Industrial Reserve Capacity 0.471 Infiltration/Inflow 0.052 Total Projected Flow 1.510 ALTERNATIVES: No Action - As the Town Is presently under a Special order of Consent (SOC) which provides a fixed timetable to eliminating the toxicity and temperature problems, no action is not an alternative, Optimum Operation of Existing Facilities - The Town has implemented this solution for the past three years. Even after bringing in outside operational assistance and performing plant modifications and upgrades the problem persists. Land Application - Land Application could be a feasible solution considering the low flow streams immediately available to receive the WWTP's discharge and was evaluated as one of the alternatives for relocation of the plant's effluent. 3 Development of Alternative Discharge Points - Wasteload Allocations: The initial step was to determine what the wasteload allocation would be if the discharge were to be relocated to the confluence of Heatherly Creek and Toms Creek, thereby taking advantage of the higher combined flows. In an effort to make such a determination a formal request was made to the State's Division of Environmental Management on May 21, 1990 for a wasteload allocation for a 1.5 mgd discharge into Toms Creek at its confluence with Heatherly Creek. A formal reply was received on August 28, 1990, a copy of which can be found in the Appendix. Because this response left questions unanswered, subsequent meetings were held with the D.E.M. staff in order to more thoroughly evaluate the effluent limits at both the present discharge point as well as the proposed new point of discharge on Toms Creek. Wasteload allocations for toxics were generated for both discharge points using the most recent data collected under the Town's pretreatment program. The complete allocations can also be found in the Appendix and they confirmed as well as expanded on the August 28th Toms Creek parameters. The only other stream in the immediate area of Pilot Mountain with a higher flows than Toms Creek is the Ararat River. Waste load &locations for the Ararat were interpolated from those generated for the Heatherly and Toms Creek. Allowable lbs/day Allowable lbs./day Allowable lbs./day Pollutant Heatherly Creek Toms Creek Ararat River 1, sme, 0 T WC 9 4%a aG)90 (U Cadmium .18 .96 11.17 Chromium 1.48 Copper .28 Nickel .92 Lead .93 Zinc 1.54 Cyanide .09 Mercury .00 Silver ,01 7.97 1.49 4.95 5.03 8.31 .47 .00 .04 22.39 3.12 39.28 11.17 22.39 2.24 .0054 .026 The remaining effluent parameters [ BODS, NH3, TSS & PH ] were assumed to be the same for both discharge points on Heatherly and Toms Creek. The actual permit for the Ararat discharge point reflects less stringent limits for all parameters. As can be seen from comparing these effluent toxic parameters, there is a definite advantage to relocating the discharge to a point with a higher stream flow. Toms Creek can tolerate over five times the toxic loading for most of the pollutants more than Heatherly Creek. Relocating the discharge would reduce the risk to the Town of effluent limit violations as well as reduce the impact on the environment should a violation occur. This is the major advantage to relocating the discharge point. 4 However, it should be noted that the relocation of the discharge to Toms Creek alone will not solve all of the treatment plant's problems. The plant's discharge presently exhibits a chronic toxicity at the Heatherly Creek dilution ratio. The ideal solution to the toxicity problem is to determine its source and remove it before it ever enters the wastestream. In pursuing this approach the Town has commissioned two studies by Burlington Labs [ see references ] , but the source or sources of the toxicity has yet to be identified. The alternative is to treat the toxicity in the plant. Burlington pursued this in their second study and determined that eight days of extended aeration did reduce the effluent's toxicity; but it did not completely eliminate it nor even reduce it to a level acceptable for discharge into Heatherly Creek. Therefore Heatherly Creek was no longer considered for continued discharge of the WWTP's treated effluent. Unless this toxicity can be removed at its source, additional treatment will be required at the plant for discharge even into Toms Creek. The costs for such a plant upgrade as well as its accompanying operating costs were considered for any solution proposing to utilize Toms Creek. As a result of these further upgrade requirements the possiblity of a discharge point on the Ararat River was brought under consideration as well. There is another advantage to relocation. A problem with high discharge temperatures, which was not addressed in the 201 Plan or the subsequent new WWTP design, has also been experienced. Relocation of the plant discharge point to a higher flow stream or to land application should also eliminate this problem. A formal NPDES application proposing the Ararat discharge was submitted to the Permits and Engineering Unit of the State's Division of Environmental Management ( DEM ) on June 5,1992. The permit was issued and became effective on February 15, 1993. Transportation Alternatives: There are two standard methods of transporting the plant effluent from the plant site to a discharge point. One method is to utilize gravity flow. From a construction perspective this requires that the route selected be generally downhill and it is highly desirable that it does not involve deep excavation. This option is only available to the Pilot Mountain WWTP if the discharge is relocated to the Heatherly Creek confluence with Toms Creek. The most obvious gravity route to Toms Creek is the one presently followed by Heatherly Creek. There are, however, other possible routes which satisfy the general construction requirements. These were also evaluated as shown on the following maps. The possible gravity routes are. 1. Paralleling the length of Heatherly Creek utilizing, a) a gravity pipe, or b) a gravity open channel 2. The East side of the railroad right-of-way [R-0-W] utilizing, a) a gravity pipe, or b) a gravity open channel 5 The other method of transportation is to pump the effluent. This often permits the use of shorter overland routes. Any alternative proposing to pump the effluent would require that an effluent pump station be constructed at the plant site. This pump station would receive the plant's treated effluent and pump it, via a force main, to the receiving stream or land application site. In developing potential routes it is highly desirable to utilize existing rights -of -way. This not only reduces the number of parties with whom the Town would have to negotiate but, since most rights -of -way are held by public entities or monopolies, costs to the Town would be minimized, thereby enhancing their feasibility. Also, by not having to deal with multiple private property owners, the Town avoids the possiblity of costly and time consuming condemnation proceedings. Accordingly, all routes developed in this study propose to utilize public or monopoly rights -of -way as much as is practical. Several rights -of -way are readily accessible from the plant site and offer attractive overland routes to Toms Creek as well as other potential discharge points. The potential force main routes are: 1. Along the east side of the railroad R-O-W to Toms Creek, or 2. Along the Duke Power high voltage transmission R-O-W to Toms Creek, or 3. Along US 52 north to Toms Creek , or 4. Along SR 268 west to Pilot Creek, or 5. Along SR 268 west to the Ararat River. Evaluation of Alternatives Gravity Routes The open channel alternatives initially appeared quite attractive due to their simplicity. However, discussions with the State determined that there are few guidelines for such an approach. The State did make the determination that the plant's effluent cannot mix with any natural stream flow before reaching Toms Creek without the more stringent effluent limits taking effect. Furthermore, there can be no introduction of extraneousness water into the channel except for rain that actually falls on the channel. Thus the effluent flow would need to be physically segregated from all other flows while being transported to Toms Creek. Although this would require a solution employing what would be essentially an aqueduct over low areas along the route, the concept was still felt to have merit until the railroad rejected any type of open ditch on their right-of-way. Since either gravity route would utilize major portions of their right-of-way, this open channel solution was not evaluated further. Any gravity piping solution would require the installation of at least a 36" diameter pipe from the plant site down to Toms Creek. Discussions with the Engineering Section of the Division of Environmental Management indicates a receptiveness to approaching this alternative as if the outfall were a storm drainage line rather than a sanitary sewer. This is a reasonable approach since the flow being transported is treated effluent and not raw sewage. With this approach, reinforced concrete pipe or even lined corrugated metal pipe could be employed, whichever application was determined to be less expensive. Also junction boxes rather than sewer manholes could be used and their spacing could be dictated by the terrain rather than State sanitary sewer regulations. The use of junction boxes instead of manholes should reduce 6 the overall number of structures as well as reduce costs on each structure . A major expense in the construction of any gravity line in the Heatherly Creek basin will be rock excavation. Quantities used in the evaluation are best estimates based on field observations and the route's topography. The topography is an additional cost factor as it will affect access for the construction operations. The contractor will experience considerable difficulty in accessing the creek route due to the creek's proximity to the railroad track and the steep terrain on the western side of the creek. The eastern side of the railroad right-of-way has several steep bluffs with minimum track clearance which will also present the contractor with access problems. The railroad should not object since the pipe would be underground, but they could be expected to charge a yearly lease for the sewer easement. This cost was included in the evaluation. Pressure Routes The most obvious route for a force main would be to parallel the track along the east side of the railroad's right-of-way from the plant site to Toms Creek. Because of the narrow track clearance along this stretch of right -of way, clearing along the entire route as well as considerable grading would be required. Again, as in the case of the gravity line, there would be a lease charge of $2,820/yr for use of the right-of-way. Initial contacts with the railroad indicated that they might be receptive to this approach. However, as the proposal was developed in more detail, additional departments within Southern Railroad became involved and some were against any grading within the right-of-way. This alternative was discarded when further negotiations with the railroad failed to produce acceptable results. A shorter potential route for the force main would be along the Duke Power high voltage transmission right-of-way from the plant site to Toms Creek, However, Duke Power's Transmission Division refused to allow the force main within their right-of-way and this alternative was also discarded. The remaining routes evaluated for the force main were all along N.C.D.O.T. right-of-way. These are: 1. Follow NC 268 west and then US 52 north to Toms Creek, discharging downstream of the water plant, or 2. Follow NC 268 west to Pilot Creek and discharge into the creek, or 3. Follow NC 268 west to the Ararat River and discharge into the river However, subsequent discussions with the State determined that the potential discharge limits for Pilot Creek would be no better than those already issued for Heatherly Creek. There being no advantage to the Town, this alternative was dropped from further consideration. Land application was considered a viable alternative that would require a force main from the plant to the application site. In selecting a site the minimum required acreage was estimated to be at least 500 Acres assuming an application rate of one quarter of an inch per day. Although no actual site was determined it was assumed that the approximate transmission distance could be reasonably estimated at three miles. Comparative Cost Estimates: Those previously discussed alternatives deemed feasible were developed and their costs estimated. Standardized costs for pump stations, aeration lagoons and lines were used so as to allow direct comparison of each alternate. otherwise, costs reflect the unique features for each particular alternative evaluated. These cost estimates include 15% for contingency, engineering fees and the present worth of new operations and land where applicable. Those solutions requiring a pump station ( Alts. 02-4) will have an annual operation and maintenance expense estimated at $ 16,500.00/yr and, when discounted over the accepted twenty year life of the project at the current USEPA discount rate( 8 %), adds $164,387.00 of present worth cost to each of the pumping alternatives. The lagoon operations are estimated to cost $ 48,000.00/yr and, when discounted over twenty years at 8%, add $478,217.00 of present worth cost to Alternatives # 1 ,2 & 4. Alternative f 1 - Gravity along Heatherly Creek to Toms Creek Aeration Lagoon $625,000.00 Clearing - 6 ac. $4000.00 $24,000.00 Grading for access $50,000.00 Rock Excavation - 8630 cy @ $50:00 $431,500.00 36" RCP 0utfall - 8630 if @ $70.00 $604,100.00 Seeding - 259,000 sf @ $0.03 $7,770.00 Tie to existing $8,000.00 Clean -out structures - 15 @ $1200.00 $18,000.00 Railroad Bore - 100 if @ $200.00 $20,000.00 Railroad Encroachment -PW 20 yrs @ 8 % $28,278.00 Subtotal $1,816,648.00 15S Contingency $272,498.00 Estimated Capital Cost $2,089,146.00 Engineering & Inspection $ 282,035.00 Total Estimated Construction Cost $2,371,181.00 Lagoon Operations Present Worth $478,217.00 Total $2,849,398.00 Use $2,850,000.00 8 Alternative *2 — Force Main along NC 52 to Toms Creek Aeration Lagoon $625,000.00 Clearing & Grading $10,000.00 Rock Excavation $150,000.00 Pump Station $150,000.00 Force Main $309,000.00 Air Release Valves $4,000.00 Seeding $6,000.00 Railroad Crossing $20,000.00 Heatherly Creek Crossing $25,000.00 Monitoring Station at Creek $12,500.00 Dodson Mill Road Crossing $3,750.00 Driveway Crossings along NC 268 $5,000.00 Subtotal $1,320,250.00 153 Contingency $198,040.00 Estimated Capital Cost $1,518,290.00 Engineering & Inspection $ 204,969.00 Total Estimated Construction Cost $ 1,723,259.00 Lagoon Operations Present Worth $478,217.00 Pump Station Present Worth $164,387.00 Total $2,365,863.00 Use $2,366,000.00 9 Alternative #3 — Force Main along NC 268 to Ararat River Clearing & Grading $10,000.00 Rock Excavation $100,000.00 Pump Station $175,000.00 Force Main $692,800.00 Air Release Valves $6,000.00 Seeding $10,400.00 NC 52 Bore $15,000.00 Road Crossing $15,000.00 Driveway Crossings along NC 268 $4,120.00 Monitoring Station at River $15,000.00 Subtotal $1,043,320.00 15% Contingency $156,500.00 Estimated Capital Cost $1,199,820.00 Engineering & Inspection $161,976.00 Total Estimated Construction Cost $1,361,796.00 Pump Station Present Worth $164,387.00 Total $1,526,183.00 Use $1,526,200.00 10 Alternative 04 — Force Main to Land Application Site Clearing & Grading $10,000.00 Rock Excavation - 1500 cy @ $50.00 $75,000.00 Pump Station $150,000.00 14" Force Main - 9150 if @ $28.00 $256,200.00 Air Release Valve - 2 co $2000.00 $4,000.00 Seeding - 191,700 sf @ $0.03 $5,751.00 NC 52 Bore - 120 If @ $125.00 $15,000.00 Road Crossing - 40 if @ $125.00 $5,000.00 Driveway Crossings along NC 268 $20,000.00 Aeration Lagoon $625,000.00 Spray Application System $330,000.00 Subtotal $1,495,951.00 15g Contingency $224,393.00 Estimated Capital Cost $1,720,344.00 Engineering & Inspection $232,246.00 Total Estimated Construction Cost $1,952,590.00 Lagoon Operations Present Worth $478,217.00 Pump Station Present. Worth $164,387.00 Total $2,595,194.00 Use $2,596,200.00 ( Land - 500 Acres @ $12,500/Ac. $6,250,000.00) To summarize the preceeding evaluation, the four feasible alternatives and their estimated costs are: Alternative # 1: Gravity along Heatherly Creek to Toms Creek $2,850,000.00 Alternative #2: Force Main along NC 52 to Toms Creek $2,366,000.00 Alternative #3: Force Main to Ararat River $1 ,526,200.00 Alternative #4: Force Main to Land Application Site $2,596,200.00 Based on this analysis the Ararat River (Alternative #3) solution is recommended. 11 User Charges and Financial Capability Assumptions - The loan is simple interest, declining annual payment for $1 ,361 ,796.00 @ 5% interest with payback to begin in 1996. Additional annual operating costs will be $ 16,500.00. Based on the preceeding assumptions, the typical residential sewer user of 5,000 gallons per month, who presently pays $5.85/month, would see their bill increase to $ 6.90/month. PUBLIC PARTICIPATION A public meeting to explain the revisions to the 201 planning and allow the opportunity for questions and comments about 201 planning was held in conjunction with a Town Council meeting on Monday, February 24, 1992 in the council meeting room of the Pilot Mountain Town Hall. The engineering consultant firm of William C. Piver & Associates made a brief presentation covering the recommendations in the 201 Facilities Plan Revision. Questions were asked but no objections were raised. ENVIRONMENTAL ASSESSMENT: GENERAL DISCUSSION This project is the result of the Special Order by Consent (SOC) No. EMC WO 93-02 entered into by the Town of Pilot Mountain and the North Carolina Environmental Management Commission. The basic requirement of the SOC is for the Town of Pilot Mountain Wastewater Treatment Plant to comply with the assigned effluent discharge limitations. The particular limitation in noncompliance is whole effluent toxicity caused by heavy metals due to lack of flow in the receiving stream, Heatherly Creek. The satisfactory solution to the compliance problem as agreed by all parties is to convey the treated effluent to the Ararat River, some 4.3 miles away. The design selected to accomplish the objective is a 1 6" diameter force main. This force main will be placed inside public roadway rights -of -way its entire route. This construction procedure will prelude any environmental damage associated with the disturbance of virgin land and minimize the costs associated with property acquisition. EXISTING ENVIRONMENT The topography and route map presented in this section shows the planned pipeline path. The topography is rolling hills with undulations from 860 MSL to 1 095 MSL. The topsoil is thin and rocky; boulder outcroppings are common. There are vast tracts of forests and pastures; however, there is little serious farming. There are many creeks and streams which typically are dry during the summer months. The only significant surface water in the region is the Ararat River. The groundwater is unpolluted; however, it is typically hard and unmineralized. Deep wells in the area deliver excellent quality. Many rural dwellings, remote to municipal utilities, have private wells. 12 NEED The paramount need for this project is to accomodate the terms of the SOC. This need is based upon the cessation of pollution of the waters of the State of North Carolina. The pollution is the result of heavy metal toxicity. Due to low flow in Heatherly Creek, the effluent is toxic with metals concentration in the parts per billion range. ALTERNATIVE ANALYSIS The choice of alternatives in the problem solution are few. They are shown below: • Do nothing. • Improved pretreatment by user industries. Install sophisticated treatment processes at the POTW. ▪ Land application. * Construct an effluent force main to the Ararat River in order to increase dilution. Do Nothing Should the Town do nothing, it would be in violation of the laws of North Carolina and subject to severe fines and further pollution of the surface waters of the State would continue. The Town of Pilot Mountain does not plan to pursue this alternative. Improve Industrial Pretreatment The user industries have already been required to install individual pretreatment systems in accordance with their specific needs. Due to the level of pretreatment required to remove extremely small amounts of contaminants involved, the cost of additional pretreatment would be great. Such pretreatment would increase the burden of the industries by the complexity of operation and disposal of generated sludge which would likely be classified as "hazardous waste." Budgetary purchase of these treatment devices is estimated between $0.5 million to $ 1.0 million per industry. Due to the necessary aggregate total expenditure, the Town pursued other methods of compliance. Install Sophisticated Treatment Processes at PTOW The PTOW does an excellent job in the treatment of the influent wastewater. The activated sludge process is designed to biologically consume the organic matter and to remove the resulting sludge by sedimentation and clarification. Any removal of dissolved inorganic substances, including heavy metals, is virtually coincidental. Preliminary studies have indicated that up to eight days of additional aeration does not allow for effluent limits to be met. Where removal of metals toxicity is the paramount objective, other unit processes are required. These could include multiple pH adjustments, oxidation-reduction, filtration or reverse osmosis. In order to objectively assay the choice of processes required to enhance the treatment, an extensive and costly pilot test program would be required after which the unit processes) would be designed and Installed. This procedure is estimated at $2 million, and a significant increase in operating cost must be anticipated. Since the additional treatment would remove but not destroy the metals, they would find their way into the sludge, thereby increasing its toxicity. This would aggravate the ultimate sludge disposal problem which is already a serious matter at Town's treatment plant. Should 13 the total improvement effort and expenditure be successful, the effluent discharge would remain in what is essentially a no -flow stream which is looked upon with great disfavor by the DEM. The major hazard associated with this alternative choice is the possibility of massive failure, wherein the planned increase in treatment was not realized, and the Town of Pilot Mountain found itself again under enforcement action. After due deliberation, this alternative was eliminated. Land Application There is considerable data available pertaining to this alternative which is based upon actual installations in North Carolina. Basic requirements for a successful installation demand an abundance of nearby land which is nearly flat topographically and demonstrates good absorption or percolation. There exists many acres of unimproved land near the POTW; however, that land is extremely hilly and very rocky with poor topsoil. Following is a summary of facts pertaining to actual land application systems where the available soils were acceptable. Sprayfield Area - 500 Acres Site Improvements - $1.95 Million Add Land Acquisition Cost Estimate for the Town of pilot Mountain Land Cost - $ 6.25 Million Site Improvements - $1.95 Mill ion Gross Total - $8.2 Million This alternative was withdrawn from consideration. Construct Pipeline to Ararat River The basic reason that the wastewater is toxic is because of the testing protocol brought about by the flow, or lack of flow, in the receiving stream, The testing protocol is designed to somewhat stimulate the effluent impact upon the specific stream. As stream flow decreases as related to effluent flow, the stream becomes overwhelmed by the effluent. Conversely, as the stream flow increases relative to the wastewater, the impact of the effluent becomes insignificant. Specifically at the Town of Pilot Mountain POTW, when the toxicity test is conducted with respect to Heatherly Creek, the result is failure; when accomplished with respect to the Ararat River, the result is successful. Therefore, if the POTW discharged to the Ararat, it would be in compliance. In order to deliver the treated wastewater to the river, there exists no possibility of a gravity pipeline. The force main would be a 16" diameter and about 4.3 miles long. Since the path would be in the public road rights -of -way, minimal property acquisition would be required. 14 Cost Estimate Force Main $1 ,526,200.00 The force main outfall to the Ararat River is the alternative of choice. ENVIRONMENTAL CONSEQUENCES a. Changes in Land Use: The pipeline will be buried in the right-of-way of public roads; therefore, no new lands will be distributed. There will be no changes of land use. b. Wetlands: There is an area of wetlands along the pipeline near the river as shown on the topographic map. An existing State Road (NC 268) goes through the wetlands. The pipeline will be buried in the shoulder of the roadway, thereby obviating any disturbance of the wetlands. c. Agricultural Lands: The pipeline will be placed in road rights -of -way, thereby disturbing no agricultural lands. d. Public Lands Such as Parks: There are no public lands in the vicinity; however, the construction will be limited to rights -of -way. e. Scenic and Recreational Areas: The major length of the project is in rural areas with little uniqueness. The land in immediate proximity to the river is used by fishermen and is quite scenic. Since the pipeline will be placed in the shoulder of an existing State Road, no new property will be distributed, and the disruption of the scenic quality will last only for a few days. t. g. Areas of Archaeological History Value: Since no new lands will be distributed by this protect, there is no historical concern. Air Quality: The project will create no new source of enduring air pollution. During the construction phase of the project, there will be dust produced by digging. This will be temporary and localized. It is unlikely that the described air quality deterioration will be as significant as plowing the nearby fields. h. Groundwater Quality: There will be no impact on groundwater quality. i. Noise Levels! The project will create no enduring source of noise caused by the construction equipment; however, it is unlikely that this will exceed that of farming equipment. Water Supplies: The Ararat and its tributaries provide a source of potable water for several communities. This force main pipeline will discharge treated wastewater directly to the river; however, Heatherly Creek, the current receptor, flows in the Ararat; therefore, there will be no net change. This situation was appraised by the Department of Environmental Management and NPDES permit No. NC0026646 was issued. k. Shellfish or Fish and Their Habitat: The point of intersection will he relocated by the project pipeline from Heatherly Creek; however, there will be no net change. 15 I. Wildlife and Their Habitats: Since this project will be constructed in road rights -of -way, wildlife habitats will be undisturbed. m. Introduction of Toxic Substance: The general understanding of a toxic substance is something that is poison which causes death to humans. The Town of Pilot Mountain treated effluent is not poison; however, the DEM has classified it as toxic to the biota in Heatherly Creek. This is due to the volumetric relationship of stream flow to wastewater flow. According to that same protocol , the effluent is not toxic to the Ararat flow. Since Heatherly Creek is a tributary, the Pilot Mountain effluent currently flows to the Ararat; therefore, no new material will be added. No toxic substances will be introduced. n. Eutrophication of Receiving Waters: Eutrophication of the Ararat will not be increased by this pipeline proiect. it is clear that eutrophication of Heatherly Creek will be reduced when the effluent discharge is removed. MITIGATING MEASURES The pipeline will be placed in existing roadway rights -of -way; therefore, natural habitat will be virtually undisturbed. Construction of the planned project will likely cause some temporary minor adverse environmental impacts which cannot be avoided. These will include expenditures of fossil fuel by the construction machinery and deterioration of air quality as well as some noise pollution. It is not likely that the total impact will be as significant as a nearby farmer preparing his fields for planting. There could be some soil erosion even though every precaution will be taken by the contractor personnel as required by the State laws. All environmental degradation will be completely mitigated by the relocation of the outfall from Heatherly Creek to the Ararat River. The creek bed will be allowed to return to its original habitat prior to POTW construction. Since Heatherly Creek is a tributary of the Ararat, there will be no net change upon the river water quality. 16 References 1. Toxicity Reduction Evaluation, Phase I Report, Town of Pilot Mountain, November 1988 by Burlington Research, Inc. 2. Extended Aeration Toxicity Reduction Study Report, Town of Pilot Mountain, July 18, 1989 by Burlington Research, Inc. 3. Administrative Code Section: 1 SA NCAC 2B .0200-Classification and Water Quality Standards Applicable to Surface Waters of North Carolina, Environmental Management Commission, August 1, 1990 4. Pilot Mountain 201 Facilities Plan 1978, Henningson, Durham & Richardson, Charlotte, N.C. 17 • Force Main along SR 268 west to Pilot Creek or Ararat River