NC0026441_Nutrient Optimization Report (Q2 2024)_20240730

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Town of *fter Ct'tp
Public Works and Utilities
Town of Slier City
NPDES#NC0026441
WWTP Nutrient Removal Optimization
Quarterly Report: 2nd 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 2nd 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 0.02 mg/I during the 2nd 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 2nd Quarter
Optimization 2024
2020
Flow(mgd) 3.26 2.55
BOD(mg/1) 228 255
NHs(mg/I) 19.5 25
TN (mg/1) 35.0 49.4
TKN (mg/L) 34.1
TSS(mg/1) 167
TP (mg/1) 3.34 2.7
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 Ibs BOD/Lbs MLVSS with MLVSS between a concentration of
3,400 to 4,200 mg/I.
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 commanity.

Optimization Implementation
During the 2nd quarter of 2024 the overall performance of the Siler City WWTP has been relatively good although
wastewater influent strengths are higher than the previous quarter. The effluent TN levels have been somewhat
elevated.The influent BOD was in a typical range however influent TN concentrations were higher this quarter.
The MLVSS concentration averaged 3,641 mg/I which is within the range recommended by the optimization
report.
The performance for TN is above the optimization report target of 15 mg/l all three months but due to lower
flows the mass discharged for 2"d quarter is less than the 11T quarter. The average mass TN discharged in Quarter
2 was approximately 11,524 Ibs/month with a total quarter mass of 34,571 lbs. Further optimization will be
needed in 2024 to comply with the reduced annual limit.
Table 2: Nutrient Removal Performance for 2nd Quarter 2024.
Influent I Effluent
April May June Average April May June Average
Flow 2.55 2.84 2.25 2.55
BOD 276 232 257 255 0.11 0.19 0.49 0.26
NH3 24 23 30 25 0.00 0.00 0.08 0.03
TN 49.9 49.0 49.2 49.4 16.95 16.32 20.95 18.07
TP 2.11 2.63 3.49 2.7 0.04 0.004 0.02 0.02
1. All concentrations reported in mg/l. Flow reported in MGD
Table 3: Operating Parameter Summary
April May June Average
MLSS (mg/1) 5,413 5,339 5,248 5,333
MLVSS (mg/1) 3,851 3,534 3,538 3,641
Ditch 1 DO (mg/1) 3.20 2.92 2.52 2.88
Ditch 2 DO (mg/1) 3.52 2.89 2.41 2.94
Conclusion
Overall plant performance during the quarter was good with excellent performance for BOD ammonia and
phosphorus.The performance during this period for Total Nitrogen was ok but is still slightly above the annual
limit level if it continues at this pace.The plants are continuing to prioritize sludge handling and solids levels in the
basins are close to optimization report recommendations.
Thank you,
Town of Siler City
Chris McCorquodal
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 rr Jr•ameivork for our success rhrough bolan,ced quvern(Inr, )0177rc partbrerships.and an engaged cornrnuniol.