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HomeMy WebLinkAbout201706201041-1�. • OuPont Fluoroproducts 22828 NC Highway 87 W Fayetteville, NC 28306-1332 aUPONr� DuPont Fluoroproducts ` MAY _ 8 2001 L DENR WATER QUALITY POINT SOURCE BRANCH May 3, 2001 CERTIFIED MAIL -RETURN RECEIPT REQUESTED Ms. Valery Stephens NCDENR —Division of Water Quality Point Source Branch 1617 Mail Service Center Raleigh, NC 27699-1617 SUBJECT: NPDES Permit Renewal Application NPDES Permit No. NC0003573 Dear Ms. Stephens: This letter officially requests the renewal of NPDES Permit No. NC0003573, which is due to expire on May 31, 2001. Enclosed you will find the original and two copies of the completed application (Form C). The required section titled "Production Data" is being submitted separately from the application due to the sensitive business confidential information that is included. Included in the permit application's section titled "Priority Pollutant Analysis" is a request to waive the annual sampling requirements for the OCPSF priority pollutants and a certification of the absence of these pollutants in the site's discharge, pursuant to 40 CFR 122.44(a)(2)(i). DuPont has demonstrated that these pollutants are not present in the wastewater discharge through five years of annual monitoring. The results of that monitoring are included in this request. Changes that have occurred since the issuance of the last permit are: • The BCH Energy Project Facility has been shutdown, sold, and dismantled. Therefore, all mention of this facility should be removed from the subject permit. • Anew DuPontTM Teflon® fluoropolymer resin manufacturing facility was started -up during December 2000. Process wastewater from this facility passes through the site's central Wastewater Treatment Plant and is discharged through Outfalls 001 and 002. • A Biomixer® aeration/mixing unit was added to the Wastewater Treatment Plant's Aeration Tank to add additional dissolved oxygen to the incoming wastewater. DuPont is requesting several changes to the effluent limitations and monitoring requirements of the renewed permit, specifically: E. I. du Pont de Nemours and Company �, , „__ ,,,�,,,,,, Ms. Valery Stephens NCDENR —Division of Water Quality May 3, 2001 • Addition of Outfall 007 to allow for the direct discharge of low -biodegradable process wastewater from the new Fluoroproducts APFO manufacturing process. If testing of the wastewater generated by this process should indicate that it would not be appropriate to direct discharge it, then the wastewater will be treated in the site's Wastewater Treatment Plant. • Addition of the Teflon? PMDF manufacturing facility and the Fluoroproducts APFO manufacturing facility to the narrative portion of Outfalls 001 and 002. • Increase of the BODS and TSS limits in response to the anticipated growth of the market for both the Butacite® and Nafion® businesses during the next five years. With this renewal application, DuPont is notifying the Division of Water Quality of its intention to reroute the site's effluent from the current effluent channel to a pipeline that will discharge preferably upstream of Lock and Dam #3, or alternately downstream of the lock and dam. The decision as to location of the discharge will depend on the results of a modeling exercise by DWQ to determine if DuPont's permitted limits would be affected by discharging upstream of the lock and dam. If you have any questions, please feel free to call me at (910) 678-1155. Enclosures Michael E. Johnson Environmental Manager DuPont - Fayetteville Works Present Operating Status NPDES Permit No. NC0003573 Process wastewater and stormwater from the various manufacturing areas are collected in the respective area sumps and ultimately conveyed via a gravity flow underground process sewer pipe to the site's central wastewater treatment plant (WWTP). Sanitary sewage is conveyed via a separate underground sewer system to the WWTP. The permitted flowrate of the WWTP is 2.0 MGD, with an actual average flowrate of approximately one MGD. This untreated wastewater is commingled in the WWTP Influent Sump where it is pumped to an 850,000 -gallon Equalization Basin. The Equalization Basin is mixed with two floating submerged mixers. Three floating surface aerators in the basin cool and aerate the incoming wastewater. A 175,000 -gallon Emergency Retention Tank is available for temporary storage of unsuitable wastewater. This unsuitable wastewater, which typically exhibit a high organic loading or a chemical to which the WWTP activated sludge is not acclimated, is eventually treated in the WWTP at a rate that allows for proper biological treatment. Wastewater from the Equalization Basin is pumped to a 250,000 -gallon Predigester Tank in which initial biological activity with the WWTP activated sludge begins. The Predigester Tank is aerated with both a floating surface aerator and diffused air. The partially treated wastewater from the Predigester Tank is pumped to a 1,700,000 -gallon Aeration Tank, The Aeration Tank is the site of the majority of the biological activity. The Aeration Tank is aerated by both a diffused air system located in the bottom of the tank, and by a floating Biomixer(I that injects air through submerged rotors. The biologically treated wastewater is then sent to two in -ground clarifiers (119,000 gallons and 168,000 gallons respectively) in parallel. The clarified treated effluent is discharged to and through Outfall 001. The wasted sludge is sent to a Dissolved Air Floatation (DAF) unit, then to a 47,000 gallon Sludge Storage Tank, and finally to a Rotary Filter for thickening. The thickened sludge is dewatered in a Screw Press, and then dried in a steam -heated dryer. The dried sludge is transported off-site to a commercial landfill. Non -contact process cooling water and non -process stormwater are conveyed via surface ditches to the site's Woodlined Ditch. In addition, excess riverwater flow and Outfall 001 effluent are discharged directly to the Woodlined Ditch. The combined, total flow of water from the site is discharged and monitored at Outfall 002. The Outfall 002 flow averaged 14.5 MGD during the period from 1996 to 2000. DuPont - Fayetteville Works Potential Faeility Changes NPDES Permit No. NC0003573 APFO Manufacturing: The DuPont — Fayetteville Works has been tentatively identified as the location for the DuPontTM APFO manufacturing process. This process will produce ammonium perfluorooctanoate (APFO), CAS No. 3825-26-1, an essential raw material for the DuPontTM Teflon® fluoropolymer resins business. The manufacturing unit will be located either near the existing Dymetrol® manufacturing building or near the Nafion® area's Vinyl Ethers South manufacturing building. APFO is recognized by DuPont and others as a biopersistent compound, meaning it remains in the body or environment for extended periods of time after exposure. Due in part to APFO's biopersistence, DuPont, alone and in collaboration with others, has made considerable investment into studying potential health effects of APFO. DuPont's medical surveillance of its own employees and epidemiological data from others in industry support its conclusion that APFO does not pose a health concern to humans or animals at levels present in the workplace or environment. DuPont has used APFO for more than forty years with no observed health effects in workers. APFO is used in low volumes and does not pose any significant acute or chronic risk. It is not a genotoxic compound. It is neither a known developmental toxin nor a known human carcinogen. APFO exhibits low environmental toxicity; tests on various aquatic life forms have shown no adverse effects even at very high doses. APFO is not bioaccumulative in the food chain. As with most fl uorochemical processes, the wastewater from the APFO manufacturing process is expected to have very little or no biological oxygen demand (BODS) value. In addition, the fluoride and fluorocarbons have been related to settleability problems in the WWTP's final clarifiers. For these reasons, DuPont proposes to create a new permitted outfall, designated as Outfall 007, with the same monitoring requirements as the currently permitted Outfall 006, through which the APFO process wastewater will be discharged directly to the site's woodlined ditch and ultimately through Outfall 002. The rational behind this new outfall is identical to that used to create Outfall 006 (See Attachment A for a letter dated March 15,1996 from Michael E. Johnson, DuPont, to Gregory Nizich, DEM). DuPont will conduct a study of the APFO process wastewater to verify the absence of significant BODS value before the project is constructed to provide support for the appropriateness to discharge of this stream directly to the woodlined ditch. In the extremely unlikely event that this wastewater exhibits BODS concentrations near the permitted limit of 24 mg/L, then DuPont will convey the wastewater to the site's WWTP for treatment and discharge at Outfall 001. The APFO wastewater will contain iodide, a new chemical to the Fayetteville Works facility. Current estimates of the wastewater indicate that there will be approximately 365 lb/day IZ that would convert to form approximately 477 lb/day of the potassium iodide salt (KI). The 7Q10 of the Cape Fear River at the DuPont location is 791 cubic feet per second. At the 7Q10 flowrate, the concentration of potassium iodide in the river would be 112 µg/L. An emergency oleum water scrubber will be included as an integral part of this process. In - the unlikely event of a release of oleum (a solution of S03 in H2SO4) inside the manufacturing building, the scrubber would remove the resulting S03 from the air. To prevent the growth of DuPont - Fayetteville Works Potential Facility Changes NPDES Permit No. NC0003573 algae and/or slime inside the scrubber, a biocide will likely be added to the water in the scrubber. There will be a purge of some volume of the scrubber water on a continuous basis, so the biocide will be discharged to Outfall 002. At this time, no decision has been made as to what biocide will be used in this scrubber, butJ when one is chosen, DuPont will submit a revised Part 5 to Section II of this application for Outfall 002 and Outfall 007, Finally, stormwater associated with the APF@ process area will be discharged directly to Outfall 002 via the site's Woodlined Ditch, Butacite® Production Increase: Due to the anticipated increases in market demand, the Butacite@ business is expecting a substantial increase in production of the DuPontTM ButaciteO Interlayer sheeting and PVB Resin during the next five years. A new Butacite@ PVB reactor is scheduled to be installed within two years, and additional improvements within the Butacite@ manufacturing processes will result in the needed production increase. See the section titled "Production Data" for more information. Nafion® Production Increase: Due to the anticipated increases in market demand, the DuPont Fluoroproducts monomers business is expecting a substantial increase in production during the next five years. For the same reason, the DuPontTM Nafion@ membrane business is expecting a substantial increase in production during the next five years. Both the monomers and membrane manufacturing areas will accomplish this expanded production capability through debottlenecking the existing processes and/or installation of new equipment. See the section titled "Production Data" for more information. _BCH Alternate Enemy Proiect: The BCH Alternate Energy Project located at the DuPont Fayetteville Works went into bankruptcy in 1998, and the project's physical facility and equipment were sold. Therefore, all reference to this facility should be removed from the subject NPDES permit. Outfa11002 Discharge Relocation: During a drought condition during the summer of 1999, the DuPont effluent channel that conveys the site's final water discharge to the Cape Fear River experienced sloughing of the streambanks into the flowing effluent, resulting in excessive sediment discharge into the river. DuPont has initiated a study to determine a cost effective remedy this situation. Currently, two options are being considered: Option 1: Collect the total flow from Outfall 002 and convey it via a pipeline to the Cape Fear River upstream of Lock &Dam #3. Option 2: Collect the total flow from Outfall 002 and convey it via a pipeline to the Cape Fear River downstream of Lock &Dam #3. Option 1 is the most attractive to DuPont at this time because it is the least expensive due to the shorter distance from Outfall 002 and the river. In addition, Option 2 would require that DuPont lay the pipeline across the government owned property of the park facility at Lock & Dam #3, otherwise the pipeline would have to run over a much longer, more circuitous route. It DuPont - Fayetteville Works Potential Facility Changes NPDES Permit No. NC0003573 is unknown whether DuPont would receive approval from the Army Corps of Engineers to lay this pipeline across their property. This proposal was presented to the Division of Water Quality, and the single concern stated by the division was that a discharge upstream of Lock & Dam #3 might be considered to be a reservoir instead of a flowing river, and as such DuPont's permitted limits for BODS, nitrogen, and phosphorous might be lowered. According to the division, a modeling exercise would have to be performed by DWQ to determine whether or not lower permit limits would result for a discharge upstream from the Lock & Dam. Given the anticipated growth of this site during the next decade, it is essential that DuPont fully understand the implications of relocating the effluent upstream of the Lock & Dam before a decision is made to do so. Therefore, DuPont is awaiting the result of the division's modeling exercise before a decision is made on which option will be pursued. DuPont - Fayetteville Works NPDES Permit No. NC0003573 Schematic of wastewater now A water balance for the site follows. Also, a schematic of wastewater flow in the Wastewater Treatment Plant follows.