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HomeMy WebLinkAboutNC0085812_NOV-2019-LV-0920 Response_20200106 (2)Department of Public Works WaterNVastewater Division 4600 Goldmine Road Monroe, NC 28110 T. 704-289-1434 F. 704-289-7395 www.unioncountync.gov January 6, 2020 W. Corey Basinger, Regional Supervisor NCDEQ 610 East Center Avenue, Suite 301 Mooresville, NC 28115 Dear Mr. Basinger, FIECMVEr)/N(J,FP;r?1DW .,,li\ Fi J ._.. _�' NGIROS MOORESVILLE REGIONAL OFFICE This letter is in response to NOV-2019-LV-0920, outlining exceedences in both monthly flow and weekly fecal that were experienced at our Grassy Branch WRF in March 2019. These exceedences were a result of continuous, high rain events in the system. In our meeting on 05/02/2019, we detailed our efforts in reducing the I&I that is entering the Grassy Branch collection system. Since that meeting our Collections team has continued working to improve the system. Such efforts include: • Smoke testing • Camera work and jetting • Visual inspections during rain events • Manhole rehab • Installation of inflow collector dishes We are also wrapping up a comprehensive flow monitoring study by Frazier Engineering. This study will give us more than 12 months of data, including both dry and wet season flow characteristics. Once we evaluate this data, we will then start micro -monitoring to pinpoint areas in the system that could profit from future repair/rehab efforts. In addition to the I&I reduction, we are in the process of finalizing our application package for a Special Order by Consent as addressed in our 5/16/19 letter. We contracted with Hazen & Sawyer Engineering to develop a stream model which has since been approved by NCDEQ. Using this information, the engineers then designed upgrades to the facility which will alleviate the issues causing these exceedences. These upgrades would include: • Anew .070MGD treatment train that would bring total plant capacity to .120MGD • Cloth -disc filters • New UV system sized for both trains • Significant changes to the influent pump station • New, larger blowers +1 AEC°EIVED/N C DFNR/DwR JAN q tN0R0; MOORFSVILLF RM-110NAL OFFICE We intend to continue our efforts finding and reducing the I&I in the Grassy Branch basin even as we address the treatment/capacity issues at the Grassy Branch WRF. If you have any questions or concerns please contact me at 704-296-4215. Sincerely, A=rew N`7 Water & Wastewater Division Director Cc: Hyong Yi, Public Works Administrator Josh Brooks, Asst. Div. Director, Water & Wastewater Bart Farmer, WRF Superintendent Greg Morgan, Utility Services Superintendent oN Co H J�\naz U �t •rTF/ CAQ`o .J Page 2