PERMIT RATIONALE FOR REISSUANCE
Magee POTW
Simpson County
Magee, Mississippi
Water NPDES No. MS0024911
September 2022

I.	CLASSIFICATION – NPDES Municipal Minor

II.	DESCRIPTION OF WASTEWATER – Domestic 

III.	DESCRIPTION OF WASTEWATER TREATMENT – Domestic wastewater is collected and treated by means of a conventional lagoon followed by disinfection.  No increase in treated effluent flow is proposed within the application.  

IV.	RECEIVING WATERS – Goodwater Creek.  The receiving stream is located within the Pascagoula River Basin and is classified as Fish and Wildlife.  At the point of discharge the receiving stream does not appear on the most recent State of Mississippi 303(d) list of evaluated or impaired waterbodies. However, the discharge does appear on a completed TMDL for pathogens. This facility disinfects, and complies with the TMDL. The 7Q10 of the receiving stream at the point of discharge is 5.0 cfs.  The instream wastewater concentration at the point of discharge is determined by the following calculation: 

IWC = {(Qw)/(Qw + QR)} * 100 

	Where:
	Qw = Design flow of the wastewater treatment facility, 0.45 MGD or 0.7 cfs
	QR = Receiving stream 7Q10, 5.0 cfs

IWC = {(0.7 cfs)/(0.7 cfs + 5.0 cfs)}*100 = 12.23 %

Only one discharge to surface waters is described within the application with no increase 	in treated effluent flow proposed in the application.  

V.	APPLICABLE GUIDELINES – 11 Mississippi Admin. Code pt. 6, Waste Load Allocation (WLA), Total Maximum Daily Load (TMDL), and Municipal Facility Guidelines (Technology).

VI.	SUMMARY OF LIMITATIONS –
	Parameters				Value				Basis
	Flow					0.45 MGD			Design
	BOD5					30 mg/l		 		WLA
	Phase I Ammonia-Nitrogen		Report, mg/l			WLA
	Phase II Ammonia-Nitrogen		10 mg/l				WLA
	TSS					90 mg/l				Technology
	Phase II Dissolved Oxygen		Report, mg/l			WLA
	Phase II Dissolved Oxygen 		> 6.0 mg/l 			WLA
	E. Coli					126 Col./100 ml 		WLA
	Chlorine, Total Residual			0.09 mg/l 			WLA
	pH					6.0 – 9.0 SU			WLA
	Total Nitrogen				Report, lb. /day			WLA
	Total Phosphorus			Report, lb. /day			WLA
	
VII.	CHANGES FROM PREVIOUS PERMIT –

 Ammonia-Nitrogen and Dissolved Oxygen permit limitations are added to the proposed draft permit. The permit limitations contained in the draft permit reflect the 2022 Waste Load Allocation for this facility’s outfall.

The permittee shall achieve compliance with the effluent limitations specified for discharge in accordance with the following schedule:

Upon issuance of this permit, the permittee shall achieve compliance with the effluent limitations specified for the parameters without a phase designation and for the parameters noted as Phase I; Phase II limitations shall not apply at this time.

Beginning upon completion and start-up of improvements needed to comply with Phase II limitations or three (3) years after the issuance of the permit, whichever comes first, the permittee shall achieve compliance with the effluent limitations specified for the parameters without a phase designation and for the parameters noted as Phase II; Phase I limitations shall no longer apply at this time. 

The permittee shall notify our office orally at least 24 hours prior to start-up and in writing no later than 48 hours after start-up.

The Permittee shall submit engineering report: Due once within 6 months (180 days) after effective date. Said report shall outline the improvement activities needed to upgrade the wastewater treatment facility to comply with the site's Phase II limitations and shall include a proposed schedule for those improvement activities. 

The Permittee shall submit progress report: Due annually - every 1 year after effective date. Said report shall update the Permittee's progress in addressing needed upgrades to the wastewater treatment facility in order to meet the site's Phase II limitations. Said report should also include an updated schedule for completing these activities.