NC0026441_Report_20240506

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Public Works and Utilities
EMC SOC WQ 522-033
Quarterly SOC Progress Report
1st Quarter 2024
Please accept this submittal as a quarterly progress report for the work and activities for the Town of Siler City under the
Special Order by Consent.
Scheduled Activities paragraph 2(a)
Quarterly Reports
Quarterly Nutrient Optimization Report and Quarterly SOC Report were submitted on January 30, 2024
Collection System Permit WQCS00056
Permit for Main Interceptor Replacement Project was Submitted on February 28, 2023, Sewer Extension Permit
was issued on April 19, 2023.
ARPA Sewer Rehabilitation Project Engineering Report was submitted on May 1, 2023, and was approved on
April 23, 2024. We are currently awaiting approval of encroachment agreements from NCDOT and Norfolk
Southern Railroad.
The Main Interceptor Project is included with scope for WWTP expansion and has been delayed based on delays
in acquiring funding. Bids were received for this project on April 4, 2024, and are planned to be presented to the
Sanford Board for Tentative Notice of Award on May 6, 2024.
All other Activities are scheduled for future quarters and are currently expected to be on schedule.
NPDES Permit NC0026441
IUP Permits were issued to Mountaire Farms, Brookwood Farms, and the Siler City Water Treatment Plant on
May 19, 2023. Mountaire Farms requested an adjudicatory hearing for their permit which was held on July 21.
Mountaire is currently appealing the results of the hearing. Appeal is scheduled to be heard on June 17, 2024.
An Authorization to Construct has been issued to Mountaire Farms for the improvements.
Supplemental Aeration Equipment has been installed in the oxidation ditch basins.The installation was
complete on May 26, 2023, with initial email notification on May 30 and a formal letter on June 29, 2023,
notifying NCDEQ of completion.
Sludge equipment was acquired for winter 2023-2024 season by December 1, 2023
6.0 MGD WWTP Expansion funding has been secured with issuance of the Letter of Intent to fund from NCDEQ
DWI. The Town received bids on this project on April 25, 2024, and this expected to be presented to the Sanford
Board for Tentative Notice of Award on May 6, 2024. Significant concerns about the schedule were raised by
several contractors during the bid and the schedule was extended to allow 30 months due to the current market
and material issues.This work will not be complete by December 31, 2024, and further discussion regarding this
activity is needed.
Chris McCorquodale
Director of Public Utilities [e-mail]
PO Box 769.311 N.Second Avenue Phone:[phone]•Fax:[phone]
Siler City,NC 27344-0769 www.silercity.org
To advance a framework for our success through balanced governance,dynamic partnerships,and an engaged community.

Water Treatment Plant
IUP Permit was issued to the Siler City Water Treatment Plant on May 19, 2023.
Construction of the WTP Pretreatment Improvements was completed on November 21st, 2023, and confirmation
submitted to NCDEQ notifying of the completion.
The WTP Solids Handling Improvements is currently in design.Town is working with McGill to revise the design
for final submission and is expected to submit for permits within 2 weeks.This activity will be behind the
scheduled begin construction date of February 1, 2024, and schedule extension request was declined.
Sludge equipment was acquired for winter 2023-2024 season by December 1, 2023
Action Items under Paragraph 4(a)
Phase 1
All Action Items associated with Phase 1 have been completed.
Phase 2
The Town has submitted plans and specifications to DWI for review and approval.As noted above,The Town received
bids on this project on April 25, 2024, and this expected to be presented to the Sanford Board for Tentative Notice of
Award on May 6, 2024.
As noted above, supplemental aeration equipment installation was completed on May 26, 2023.
As noted above,the Town is issued updated IUPs on May 19, 2023. Authorization to Construction was issued to
Mountaire Farms on March 15, 2024
Phase 3
No overflows from the Town's WTP have occurred from date of execution of the SOC.
As noted above, Construction of the WTP Pretreatment Improvements was completed on November 21st, 2023. During
startup an issue with the existing influent pipe was determined which caused a hydraulic constraint on operation.
Replacement of this pipe has been completed and startup of the facility is scheduled for May 1, 2024.
Summary of Expenditures was submitted in February 2024.
Phase 4
Sludge equipment was acquired for winter 2023-2024 season by December 1, 2023
Other activities are scheduled for future quarters.
Additional Wastewater Flow Pursuant to Paragraph 4
No additional flows have been released since the last report.
Thank you,
Town of Siler City
Chris McCorq ale
Chris McCorquodale
Director of Public Utilities [e-mail]
PO Box 769.311 N.Second Avenue Phone:[phone]•Fax:[phone]
Siler City,NC 27344-0769 www.silercity.org

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NPDES#NC0026441
WWTP Nutrient Removal Optimization
Quarterly Report: 1st Quarter 2024
Introduction
In accordance with NPDES Permit requirements this report is provided to document implementation of the optimization
report and performance of the WWTP during the 1st quarter of 2024.The primary focus of this information is nutrient
removal, however data on plant operations for other parameters are included as they influence the nutrient removal
performance.
Phosphorus (TP) removal is achieved with chemical precipitation and performance has been consistently good with
effluent TP averaging less than 0.03 mg/I during the 15Y quarter 2024.Therefore, no further review of TP operation is
included.
Optimization Report Recommendations
The optimization report was prepared in 2020 based on data from January to September of 2020. Operating parameters
at the time are shown in Table 1 below.
Table 1: Influent Wastewater during Optimization Study
Daily Daily Average
Parameter Average during for 3rd Quarter
Optimization 2023
(2020)
Flow(mgd) 3.26 3.12
BOD (mg/I) 228 222
NH3(mg/I) 19.5 20
TN (mg/l) 35.0 42.5
TKN (mg/L) 34.1
TSS (mg/I) 167
TP(mg/I) 3.34 1.8
The report recommends utilizing Simultaneous Nitrification/Denitrification (SNDN)to achieve nitrogen reduction.The
recommended parameters include maintaining dissolved oxygen (DO) in the oxidation ditches between 0.8 to 1.2 mg/I
and maintaining a FM ratio of 0.04 to 0.05 lbs BOD/Lbs MLVSS with MLVSS between a concentration of 3,400 to 4,200
mg/I.
Optimization Implementation
During the 1st quarter of 2024 the overall performance of the Siler City WWTP has was mixed with relatively good
months in January and March and poor performance in February. The influent BOD has remained relatively low,similar
to the 2023 and influent TN concentrations were slightly lower this quarter.
During February excessive solids were received from the Water Treatment Plant with high iron concentrations which
caused a plant upset.The Town commenced higher frequency of pressing sludge and hauling sludge from the WTP
Chris McCorquodale
Director of Public Utilities [e-mail]
PO Box 769.311 N.Second Avenue Phone:[phone]•Fax:[phone]
Siler City,NC 27344-0769 www.silercity.org
To advance a framework for our success through balanced governance,dynamic partnerships,and an engaged community.

directly to the WWTP to sludge holding to minimize the potential for sludge in the biological process.The Town also
received two loads of mixed liquor from the Sanford WWTP to help reestablish the biology and worked with Hazen for
additional testing to get the plant back in shape.The plant was able to recover by approximately March 4, 2024 and
March testing indicates improved results.
The effluent TN concentration has come down some from previous quarters but remains somewhat higher than
desirable at an average of 15.66 mg/I for the quarter.The MLVSS concentration averaged 3,200 mg/I which is just below
the range recommended by the optimization report.
The performance for TN is above the optimization report target of 15 mg/I for two of the three months but is very close
with an average of 15.66 for the quarter. Flow during this quarter has increased, likely due to winter rainfall impacts.
The average mass TN discharged in Quarter 1 was approximately 12,200 lbs/month with a total quarter mass of 36,673
lbs. Further optimization will be needed in 2024 to comply with the reduced annual limit.
Table 2: Nutrient Removal Performance for 1st Quarter 2024.
Influent Effluent
January February March Average January February March Average
Flow 3.29 2.77 3.31 3.12
BOD 195 239 233 222 3.51 16.73 1.30 7.18
NH3 20 20 21 20 3.38 6.15 0.54 3.35
TN 39.6 41.8 46.1 42.5 15.10 17.70 14.17 15.66
TP 1.49 1.95 2.06 1.8 0.02 0.03 0.05 0.03
1. All concentrations reported in mg/I. Flow reported in MGD
Table 3: Operating Parameter Summary
January February March Average
MLSS (mg/I) 4465 4996 4976 4812
MLVSS (mg/I) 3154 3207 3267 3209
Ditch 1 DO (mg/I) 4.22 3.53 2.20 3.32
Ditch 2 DO (mg/I) 3.42 2.75 1.41 2.52
Conclusion
Overall plant performance during January and March was good but upsets in February resulted in high BOD and
ammonia duringthatperiod.Theplants are continuingto prioritize sludge handling and solids levels in the basins are
close to optimization report recommendations.The performance during this period for Total Nitrogen was ok but is
slightly above the annual limit level if it continues at this pace.
Thank you,
Town of Siler City
Chris McCorquodale
Chris McCorquodale
Director of Public Utilities [e-mail]
PO Box 769.311 N.Second Avenue Phone:[phone]•Fax:[phone]
Siler City,NC 27344-0769 www.silercity.org
To advance a framework for our success through balanced governance,dynamic partnerships,and an engaged community.