PERMIT RATIONALE FOR REISSUANCE
Sunflower POTW
Sunflower County
Sunflower, Mississippi
Water NPDES No. MS0024384
June 2022

I.	CLASSIFICATION – NPDES Municipal Minor

II.	DESCRIPTION OF WASTEWATER – Municipal Wastewater

III.	DESCRIPTION OF WASTEWATER TREATMENT – Municipal wastewater is collected and treated by means of a 3-cell facultative lagoon followed by chlorine disinfection and de-chlorination using sulfur dioxide prior to discharge.  Only one discharge to surface waters is described in the application with no increase in treated effluent flow proposed.

RECEIVING WATERS – Big Sunflower River.  The receiving water is located within the Yazoo River Basin and is classified as Fish and Wildlife.  The Big Sunflower River does not appear on the current State of Mississippi 303(d) List of Impaired Waterbodies.  The receiving waters are listed on a completed TMDL for Organic Enrichment/ Low DO, Nutrients, and Sediment/Siltation (June 2003).  The permit, as written, satisfies the conditions of the TMDL. 

At the point of discharge, the 7Q10 for the receiving stream is 100 cfs.  The instream wastewater concentration at the point of discharge can be determined by the following calculation: 
IWC = {(Qw)/(Qw + Qr)}*100

Where, Qw = Design flow of the wastewater treatment facility, 0.24 MGD or 0.372 cfs
             Qr = Receiving stream 7Q10, 100 cfs

IWC = {(0.372 cfs)/(0.372 cfs + 100 cfs)}*100 = 0.37%

IV.	APPLICABLE GUIDELINES – 11 Mississippi Admin Code pt. 6, State of Mississippi Water Quality Standards (MSWQS), Municipal Facility Guidelines (Technology), Wasteload Allocation (WLA), TMDL

V.	SUMMARY OF LIMITATIONS – 

Parameter			Flow			Basis
Flow			0.24 MGD			Design
BOD5			45 mg/L 			Technology
TSS			90 mg/L 			Technology
E. coli			126 Col./100mL			MSWQS
Chlorine, Total Residual	1.0 mg/l maximum		WLA
	Total Nitrogen			Report			WLA
	Total Phosphorous		Report			WLA
	pH 			6.0 – 9.0 SU			MSWQS	

VI.	CHANGES FROM PREVIOUS PERMIT – 

Influent monitoring and reporting for Total Nitrogen and Total Phosphors have been included in the permit based on Municipal Facility Guidelines.