PERMIT RATIONALE FOR REISSUANCE
Gloster POTW
Amite County
Gloster, Mississippi
Water NPDES No. MS0020818
July 2021

I.	CLASSIFICATION – NPDES Municipal Minor

II.	DESCRIPTION OF WASTEWATER – Domestic

III.	DESCRIPTION OF WASTEWATER TREATMENT – Domestic wastewater is collected and treated via an aerated lagoon followed by chlorine disinfection prior to discharge. Only one discharge to surface waters is described within the application with no increase in treated effluent flow proposed. 

IV.	RECEIVING WATERS – Unnamed Creek into Beaver Creek. The receiving waters are located in the South Independent Streams drainage basin and are classified as Fish and Wildlife. At the point of discharge, the receiving stream does not appear on the current State of Mississippi 303(d) List of Impaired Waterbodies, nor does the discharge appear on a completed Total Maximum Daily Load (TMDL).

At the point of discharge, the 7Q10 for the receiving stream is 0.08 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, 0.19 MGD or 0.29 cfs
		 Qr = Receiving stream 7Q10, 0.08 cfs.

IWC = {(0.29 cfs)/(0.29 cfs + 0.08 cfs)}*100 = 78 %

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

CHANGES FROM PREVIOUS PERMIT – 

VI.	E. coli has replaced fecal coliform as the bacterial indicator for all freshwaters in Mississippi designated as Recreation, Fish and Wildlife Support, and/or Public Water supply. 

Total Nitrogen and Total Phosphorus effluent monitoring and reporting requirements have been added to the draft permit as recommended in the Wasteload Allocation developed for the discharge.

VII.	SUMMARY OF DISCHARGE LIMITATIONS – 

Parameter		Value				Basis
Flow			0.19 MGD		Design
BOD			25 mg/l 			WLA
NH3-N		2 mg/l				WLA
Dissolved Oxygen	≥ 6.0 mg/l		WLA
TSS 			45 mg/l 			Technology
E. coli			126 Col./100mL 	MSWQS
pH			6.0 to 9.0 S.U.	MSWQS
Chlorine		0.014 mg/l		MSWQS, IWC
Total Nitrogen		Report lbs/day	WLA
Total Phosphorus	Report lbs/day	WLA