PERMIT RATIONALE FOR REISSUANCE
Dalewood Sewer District, Plant Number 1
Lauderdale County
Lauderdale, Mississippi
Water NPDES No. MS0057126
April 2026

I.	CLASSIFICATION – NPDES Municipal Minor

II.	DESCRIPTION OF WASTEWATER – Municipal Wastewater

III.	DESCRIPTION OF WASTEWATER TREATMENT – Domestic wastewater is collected and treated biologically by means of an activated sludge treatment system. No increase in flow is proposed within the application. 

IV.	RECEIVING WATERS – Little Red Creek. At the point of discharge the receiving stream does not appear on the updated 2024 State of Mississippi 303(d) List of Impaired Waterbodies. The facility’s discharge is not listed in a completed TMDL. The receiving water is located in the Tombigbee River drainage basin and is classified as Fish & Wildlife. 

At the point of discharge the 7Q10 for the receiving stream is 0.5 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, 0.35 MGD or 0.54 cfs
 Qr = Receiving stream 7Q10, 0.5 cfs.

IWC = {(0.54 cfs)/(0.54 cfs + 0.5 cfs)}*100 = 52.01%

V.	APPLICABLE GUIDELINES – 11 Mississippi Admin Code Pt. 6, State of Mississippi Water Quality Standards (MS WQS), Municipal Facility Guidelines (Technology), Wasteload Allocation (WLA)

VI.	SUMMARY OF DISCHARGE LIMITATIONS – 

Parameter			Value			Basis
Flow				0.35 MGD			Design
BOD5				10 mg/l (Monthly Average)		WLA
TSS				30 mg/l (Monthly Average)		Technology
NH3-N				2 mg/l (Monthly Average)		WLA
E. coli				126 Col./100ml			MS WQS
Chlorine, T.R.			0.011 mg/l			Technology
Dissolved Oxygen		6.0 mg/l (Minimum)			MS WQS
pH				6.0 – 9.0 S.U.			MS WQS
Total Nitrogen			Report lbs/day			WLA
Total Phosphorous		Report lbs/day			WLA

The minimum and maximum values for Influent pH, Dissolved Oxygen in aeration unit, and 30-Minute Sludge Settleability in aeration unit must be reported