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HomeMy WebLinkAboutNC0023086_Technical Assistance Inspection_20210630 SENT VIA ELECTRONIC MAIL ONLY: NO HARD COPY WILL BE MAILED. June 30, 2021 Zelerie Rogers, Town Manager Fontana Dam Village E-mail: zelerie.rogers@fontanavillage.com SUBJECT: Technical Assistance Inspection Report Town of Fontana Dam WWTP NPDES WW Permit No. NC0023086 Graham County Dear Permittee: The North Carolina Division of Water Resources conducted a Technical Assistance Inspection of the Town of Fontana Dam WWTP on 6/01/2021. This inspection was conducted to access the facility for causes and potential solutions to challenges operating the #1 Secondary Clarifier to meet compliance with the conditions and limitations specified in NPDES WW Permit No. NC0023086. The findings and comments noted during this inspection are provided in the enclosed copy of the inspection report entitled "Compliance Inspection Report". A response to this inspection report is not required. If you should have any questions, please do not hesitate to contact me with the Water Quality Regional Operations Section in the Asheville Regional Office at 828-296-4500 or via email at tim.heim@ncdenr.gov. Sincerely, Tim Heim, P.E., Environmental Engineer Water Quality Regional Operations Section Asheville Regional Office Division of Water Resources, NCDEQ ATTACHMENTS Ec: LF Dennis.Pillkington@fontanavillage.com DocuSign Envelope ID: 5089D756-A2B0-47E1-AB88-DAF3F216FA2D EPA United States Environmental Protection Agency Washington, D.C. 20460 Water Compliance Inspection Report Form Approved. OMB No. 2040-0057 Approval expires 8-31-98 Section A: National Data System Coding (i.e., PCS) Transaction Code NPDES yr/mo/day Inspection Type Inspector Fac Type 1 N 52 NC0023086 21/06/01 D S31112171819 20 21 66 Inspection Work Days Facility Self-Monitoring Evaluation Rating B1 QA ----------------------Reserved------------------- N67707172 73 74 75 80 Section B: Facility Data Name and Location of Facility Inspected (For Industrial Users discharging to POTW, also include POTW name and NPDES permit Number) Town of Fontana Dam WWTP Fontana Village Resort Fontana Dam NC 28733 Entry Time/Date Permit Effective Date Exit Time/Date Permit Expiration Date 10:00AM 21/06/01 17/11/01 Name(s) of Onsite Representative(s)/Titles(s)/Phone and Fax Number(s) /// Daniel Dennis Pilkington/ORC/828-498-2271/ Other Facility Data 10:00PM 21/06/01 22/10/31 Name, Address of Responsible Official/Title/Phone and Fax Number Zelerie Rogers,PO Box 128 Fontana Dam NC 287330128/Town Administrator/828-498-2107/ Contacted No Section C: Areas Evaluated During Inspection (Check only those areas evaluated) Other Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) (See attachment summary) Name(s) and Signature(s) of Inspector(s)Agency/Office/Phone and Fax Numbers Date Timothy H Heim DWR/ARO WQ/828-296-4665/ Signature of Management Q A Reviewer Agency/Office/Phone and Fax Numbers Date EPA Form 3560-3 (Rev 9-94) Previous editions are obsolete. Page#1 DocuSign Envelope ID: 5089D756-A2B0-47E1-AB88-DAF3F216FA2D 6/30/2021 6/30/2021 NPDES yr/mo/day 21/06/01 Inspection Type D3111218 1 Section D: Summary of Finding/Comments (Attach additional sheets of narrative and checklists as necessary) Tim Heim of the Asheville Regional Office performed a Technical Assistance Inspection concurrent with a Compliance Evaluation Inspection (led by Lauren Armeni) of the WWTP on June 1, 2021. Dennis Pilkington (ORC) and Jason Duke (BORC in training) assisted with the inspection. Observations: The ORC stated the Operation of the #1 Secondary Clarifier (#2 is not in service) sludge collector drive results in the generation of unacceptably high TSS and has resulted in effluent permit violations. Facility staff does not operate the clarifier drive to avoid generating violations. Sludge is wasted from the clarifier by pumping to the digester or headworks. This wastewater facility appears to be operating at the end or past its design life and many components are experiencing significant wear. The facility also experiences significantly lower flows than it was originally designed for, which can cause significant operating challenges. Due to influent conditions beyond the control of the facility, MLSS in the aeration basin is maintained at a relatively low concentration (<100 mg/L) compared to other similar facilities of this type. The facility receives a significant amount of flow from backwashing of filters at the Water Treatment Plant, which may contribute to the operating challenges. The #1 Secondary Clarifier is a rectangular type with a gear and drive chain-based sludge removal system. The ORCs have attempted to vary the sludge blanket depth and other common means of adjusting conditions in this type of clarifier to improve conditions, but this has not led to an improvement. Potential Causes: In the experience of the inspectors, this type of clarifier can be very difficult to operate and is known to cause effluent issues when the sludge drive unit is operated. The composition of the sludge blanket may also hinder settling and be vulnerable to re-suspension of suspended solids, which is due to the influent wastewater quality and operating conditions. Possible Solutions: 1. Replace or upgrade the clarifier and other related facility components. This could be done by specifically selecting a new secondary clarifier for the type of conditions the facility experiences (which are atypical), or replacement of the entire WWTP. This is the recommended option. 2. Contact a qualified specialist to investigate plant operations, specifically influent characteristics and the MLSS concentration in the aeration basin, and whether changes can be made to operate in ranges more typical of a biological treatment process (> 1,500 mg/L is typically considered in the low range). Improved biological treatment could result in improved sludge settling and removal characteristics in the secondary clarifier. 3. Chemical Settling Aids. It is possible that the addition of chemicals (polymers and/or settling aids) could improve sludge blanket conditions and prevent re-suspension of solids during operation of the drive unit. This would have to be evaluated by a specialist and require bench testing. This option is not recommended due to long term cost, complexity, and potential for unintended adverse effects. 4. Alternate means of solids removal. The operators could discontinue using the clarifier sludge removal drive system permanently and attempt an alternative hydraulic/mechanical means of wasting solids from the clarifier that does not NC0023086 17 (Cont.) Page#2 DocuSign Envelope ID: 5089D756-A2B0-47E1-AB88-DAF3F216FA2D Permit:NC0023086 Inspection Date:06/01/2021 Owner - Facility: Inspection Type: Town of Fontana Dam WWTP Technical Assistance result in effluent violations. This option is not recommended as a long term solution due to the additional effort, equipment, and manpower involved. Normal treatment operations would also potentially be disrupted. Note: An additional component of concern is the manual bar screen. Current conditions require the screen to be manually raked and for solids to dry in open air, which has the potential to create nuisance conditions and a health hazard. It is recommended that this unit be upgraded to avoid these conditions. Page#3 DocuSign Envelope ID: 5089D756-A2B0-47E1-AB88-DAF3F216FA2D Permit:NC0023086 Inspection Date:06/01/2021 Owner - Facility: Inspection Type: Town of Fontana Dam WWTP Technical Assistance Other Yes No NA NE The ORC stated that the Operation of the #1 Secondary Clarifier (#2 is not in service) sludge collector drive results in the generation of unacceptably high TSS and has resulted in effluent permit violations. A TA investigation was performed at the request of the ORC by the ARO Environmental Engineer (Heim). Comment: Page#4 DocuSign Envelope ID: 5089D756-A2B0-47E1-AB88-DAF3F216FA2D