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Home My WebLink AboutNC0004243_Report Follow-up_20150921 North Carolina Department of Environmental Quality Pat McCrory Donald R. van der Vaart Governor Secretary September 21, 2015- RECEIVED/DENR/DWR Mr.John J. Moss i 4 2015 Coats American Inc. Sevier Plant Water Quality Permitting Section P.O. Box 368 Marion, North Carolina 28752 Subject: Environmental Response and Recommendations Report Review Follow-Up Sevier Plant/Coats American WWTP NPDES Permit,No. NC0004243 McDowell County, N.C. Dear Mr. Moss: The North Carolina Department of Environment Quality (NCDEQ) received the Environmental ` Response and Recommendations Report (Report) produced for Coats American, Inc. (Coats) by its consultant, ERM, Inc. (ERM) on July 20, 2015. NCDEQ transmitted a Report Review with additional questions on August 7, 2015 and ERM responded on behalf of Coats on September 4, 2015 (Response). The Asheville staff of the NCDEQ Division of Water Resources (DWR) has completed its,review of the September 4, 2015 Response and offers the following additional comments: Comment 9; page 2: Coats American is 'in the process of designing the relocation of the backwash line from the ash pond and.rerouting to wastewater treatment. Provide an estimate of the quantity of flow from this activity that will be rerouted to the wastewater treatment plant. • Comment 12; page 3: The external storage-area is-bermed and each tank is located within a containment area. It was observed that containment around the silicon tanks and the caustic off-load pipe.is compromised by a large dad(in the concrete containment wall. Are there plans to correct this vulnerability in the secondary containment? . North Carolina Division of Water Resources—Asheville Regional Office 2090 U.S.Highway 70,Swannanoa,N.C. 28778 Phone(828)296-4500 FAX (828)299-7043 Internet: http.//portal ncdenr.orglweblwq/ An Equal Opportunity/Affirmative Action Employer • Mr. John J. Moss September 18, 2015 Page 2 of 4 Comment 12: Discharge of uncontaminated accumulated water is conducted by authorized personnel only, who log the activity. How do authorized personnel determine that water inside the secondary containment area is uncontaminated? Is the accumulated water discharged to a nearby storm drain? When was the last logged discharge event and how much water was released? Comment 13: Has an inventory loss evaluation been conducted on the internal chemical storage area (not including the vertical caustic storage tank)? If not, are there plans to conduct an inventory loss evaluation in this area? Comment 14: Caustic piping integrity has - not been verified. It was observed that many t R: of the metal lines associated with the vertical caustic tank are showing signs of corrosion. A buildup of salts is visible on a h li number of joints associated with the piping system. It was also observed that a 14. distribution line from the vertical caustic h w tank was recently rerouted and/or repaired (see photo). Have there been any releases Th' w` . or spills of caustic (past or present) from the vertical caustic tank? Is the buildup of salts on the pipe joints a sign of leakage? Please describe the circumstances which led to the repairs to the distribution lines. Are there plans to verify the integrity of the vertical caustic tank and the associated piping? • x r aka f Comment 15: Raw water is 114:r 'ti fr` � ` 4 � obtained from Armstrong Creek and pumped to the mix basin, ' 414; �%j=s ' where caustic and alum are ;41- K gar r * ,: injected. A buildup of salts is z visible on piping joints �l � r 3 associated with the caustic day e, ( , '` f° tanks. Salts are also visible on 3' 1fi4:p.tf,' the raw water pipe and u = adjacent wall. Have there been any releases or spills of caustic A (past or present) from the �t caustic day tank? Is the buildup of salts a sign of leakage? Are the day tanks automatically refilled or are they manually refilled on a daily basis? ,/ Mr.John J. Moss September 18, 2015 Page 3 of 4 Comment 21: This screening level model indicates that approximately 400 — 500 gallons of caustic would have been necessary to cause the fish kill. According to a United Nations Environmental Program report on sodium hydroxide (Attached), acute toxicity for aquatic organisms is dependent upon the buffering capacity of the receiving stream. LC50 values of acute toxicity tests with aquatic organisms range between 33 and 189 mg/I. Results of aquatic toxicity tests with sodium hydroxide are based on exposure times ranging from 24 hours to 96 hours and are specific to a given fish species. As an example, a 24-hour toxicity test with goldfish revealed an LC50 of 160 mg/I. The incident in the North Fork points to a fast moving event given the moderate stream gradients (reduced exposure times) and the number of fish and amphibian species involved. If the fish kill is related to sodium hydroxide then the release would likely require a greater volume and concentration than the one portrayed in the dilution model. Was exposure times considered in the model? Based on the aquatic toxicity data submitted, is the modeled concentration in the North Fork (37-35 mg/I) and the limited exposure time (4 hours) adequate to produce a large die-off of multiple fish species? Comment response 22: Coats American has discovered that the gauge on its caustic storage tank is-not accurate or reliable when volume drops below 4,000 gallons. The volume in the [caustic storage] tank was below 4,000 gallons in the beginning of July. If the volume gauge is unreliable, how do plant personnel determine when to order additional caustic? In other words, what is the process for resupplying the vertical caustic tank? Is the daily volume for the vertical caustic tank recorded? When was the last time (prior to July 1) the vertical caustic tank was resupplied and what was the volume? What was final volume after the tank was resupplied? Comment response 1; Page 8: Process wastewater from the facility typically exhibits a pH of 7- 8.5 (as measured on 8/31/2015). In response 20, you state the amount of caustic [used] varies depending on the type of dyeing operation. Is it possible that the actual pH range of the process wastewater is much greater than the range quoted above and is dependent upon the type of dyeing operation? Proposed site assessment activities; inactive sludge drying bed: Exploratory borings or trenches will be excavated in the general vicinity of the inactive sludge drying bed area to assess the lateral and depth limits of residual sludge material based on visual observation. Site reconnaissance on July 2 identified potential biosolids in the unnamed tributary. Assessment of the inactive sludge drying bed should extend to the unnamed tributary and quantify any biosolids remaining in the stream. It was also observed that a portion of the inactive sludge drying bed is actively eroding into the unnamed tributary. All biosolids must be prevented from entering waters of the state. It was also observed that coal ash extends around the perimeter of Mr. John J. Moss September 18, 2015 Page 4 of 4 the inactive sludge drying beds. The depth and areal extent of the coal ash needs to be assessed. Proposed site assessment activities; inactive sludge drying bed: A composite sample of residual sludge will be collected from excavations for laboratory analyses of the primary potential COCs. A sample of the biosolids should be collected and analyzed by the Toxicity Characteristic Leaching Procedure (TCLP). If you have questions concerning this matter, please do not hesitate to contact me at 828-296- 4500. Sincerely, Timothy Heim, P.E. Environmental Engineer Water Quality Regional Operations, DWR Asheville Regional Office cc: WQ Asheville Files DEMLR ARO Stormwater MSC 1617-Central Files-Basement WQ Enforcement/NPDES Point Source Branch G:\WR\WQ\McDowell\Wastewater\Industrial\Coats 04243\ERM ER3 Report Response Letter 2.doc