Loading...
HomeMy WebLinkAboutNC0025496_Speculative Limits_19990716NPDES DOCWIENT !SCANNING: COVER SHEET NC0025496 Lincolnton WWTP NPDES Permit: Document Type: Permit Issuance Wasteload Allocation Authorization to Construct (AtC) Permit Modification Complete File - Historical Correspondence te, `�'-' 1..-,...:+<'''a"` �-Speculative Limits '4,, Instream Assessment (67b) Environmental Assessment (EA) Permit History Document Date: July 16, 1999 This document is printed on reuse paper - ignore any content on the reizerse side State of North Carolina Department of Environment and Natural Resources Division of Water Quality James B. Hunt, Jr., Governor Wayne McDevitt, Secretary Kerr T. Stevens, Director July 16, 1999 Mr. David E. Lowe. City Manager City of Lincolnton Post Office Box 617 Lincolnton, North Carolina 28095 Al;� NCDENR NORTH CAROLINA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES Subject: Dear Mr. Lowe: Speculative Limits Lincolnton WWTP NC0025496 Lincoln County The purpose of this letter is to provide speculative limitations for the proposed expansion of the Lincolnton WWTP from 6.0 MGD to 9.0 MGD. In light of current water quality concerns in the Catawba River Basin and more specifically in the Lake Wylie Watershed, the Division is holding permitted load for expanding facilities at no more than existing levels. Additionally, in order to provide continued protection of the 5.0 mg/L dissolved oxygen standard, ammonia limitations will be installed when the permit is renewed in 2000. Speculative effluent limitations for renewal at 6.0 MGD and expansion from 6.0 MGD to 9.0 MGD are provided in the table below: Flowrate 6.0 MOD Renewal 9.0 MOD Winter BOD (mg/L) 30.0 20.0 NH3-N (mg/L) 7.5 5.0 TSS (mg/L) 30.0 30.0 Phenols (µg/L) 9.3 6.2 Fecal (#/100 ml) 200 200 pH (SU) 6.9 6.9 TRC (µg/L) - 28 Under current Division policy, effluent residual chlorine limits and dechlorination facilities are required for all new or expanding discharges proposing the use of chlorine for disinfection. Should an alternate form of disinfection be employed, such as ultraviolet light. the chlorine limitation and associated monitoring will be waived. As the result of nutrient concerns in the Catawba River Basin, the City should plan on designing a system upon expansion that is capable of removing total nitrogen to 6.0 mg/L and total phosphorus to 1.0 mg/L. Although no effluent limitations for nitrogen and phosphorus are 1617 MAIL SERVICE CENTER. RALEIGH. NORTH CAROLINA 27699-1617 - TELEPHONE 919-733-5083/FAX 919-733-0719 AN EQUAL OPPORTUNITY AFFIRMATIVE ACTION EMPLOYER - 50% RECYCLED/ 10% POST -CONSUMER PAPER anticipated at this time, limits may be necessary at some point in the future should nutrient studies indicate that nutrient enrichment is occurring. Finally, the Division recently reviewed an Environmental Assessment for the proposed expansion to 9.0 MGD. The only remaining outstanding comment relates to discharge alternatives. The EA did not adequately address alternatives. Such an alternatives analysis must be completed before the Division will consider any expansion of the City's discharge. In order to save the City valuable time and money, it is strongly recommended that this engineering alternatives analysis be included with the environmental assessment before project planning proceeds any further. If you have any questions or comments regarding these speculative limitations, please do not hesitate to contact Mark McIntire at telephone number (919) 733-5083, extension 553. Sincerely David A. Goodrich NPDES Supervisor Cc: Central Files NPDES Permit File Mooresville Regional Office, Water Quality Planning Branch, Gloria Putnam NCDENR/DIVISION OF WATER QUALITY WATER QUALITY SECTION / N PDES UNIT )ULY 13, 1999 MEMORANDUM To: PERMIT/WASTELOAD ALLOCATION FILE NC002 5496 FROM: MARK MCINTIRE SUBJECT: SPECULATIVE EFFLUENT LIMITATIONS RATIONALE CITY OF LINCOLNTON - NC0025496 LINCOLN COUNTY - 030835 The Division received a request for speculative effluent limitations from J. N. Pease Associates on behalf of the City of Lincolnton on May 21, 1999. Speculative limits for an expansion from 6.0 MGD to 9.0 MGD were requested. Additionally, the City has anticipated a change in effluent limitations at 6.0 MGD upon renewal and requested speculative renewal limits as well. Because of the widespread occurrence of transitional waters in the Catawba River Basin, management strategies have been recommended for oxygen -consuming wastes as well as nutrients. A speculative limitations letter was sent to the City in 1992. Limits conveyed to the City in this letter follow: Flowrate 6.0 MGD Existing Renewal 9.0 MGD BOD (mg/L) _ 30.0 30.0 20.0 NH3-N (mg/L) - 7.5 5.0 TSS (mg/L) 30.0 30.0 30 Phenols (µg/L) - 9.3 6.2 Fecal (#/ 100 ml) 200 200 200 pH (SU) 6-9 6-9 6-9 TRC (j.tg/L) - 28 28 The basin plan recommends 15.0 mg/L BOD5 and 4.0 mg/L NH3-N limitations for new or expanding discharges in Catawba watersheds draining to lakes. Lincolnton's discharge is not considered in the area of influence of Lake Wylie, however oxygen - consumption protection is necessary nonetheless. Ammonia limits were never installed upon renewal at 6.0 MGD. The 7.5 mg/L ammonia limit identified in the 1992 spec letter will be included in the spec letter resulting from this memo. Oxygen -consumption limitations were established such that no increase in permitted Toad would be realized. This strategy will be maintained.