PERMIT RATIONALE FOR REISSUANCE
Crowder POTW
Quitman County
Crowder, Mississippi
Water NPDES No. MS0034304
March 2019

I.	CLASSIFICATION – NPDES Minor Municipal 

II.	DESCRIPTION OF WASTEWATER – Municipal Wastewater

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

IV.	RECEIVING STREAM - Panola-Quitman Floodway. This waterbody is in the Yazoo River drainage basin and is 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. The draft permit contains Total Nitrogen and Total Phosphorus limits that comply with the Total Maximum Daily Load (TMDL) for Nutrients and Organic Enrichment/Low Dissolved Oxygen in the Panola-Quitman Floodway (June 2008).

At the point of discharge, the 7Q10 for the receiving stream is 330 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, 0.16 MGD or 0.25 cfs
		Qr = Receiving stream 7Q10, 330 cfs.

IWC = {(0.25 cfs)/(0.25 cfs + 330 cfs)}*100 = 0.075 %

V.	APPLICABLE GUIDELINES – 11 Mississippi Admin Code pt. 6, Municipal Facility Guidelines (Technology), Wasteload Allocation (WLA)

VI.	CHANGES FROM PREVIOUS PERMIT – 

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, Total Phosphorus, and Ammonia Nitrogen limits have been added to the draft permit in accordance with the limits developed in the Wasteload Allocation for the facility dated February 19, 2019. 

VII.	SUMMARY OF LIMITATIONS – 

Parameter				Flow			Basis
Flow					0.16 MGD		Design
BOD5					30 mg/l 		WLA
Ammonia Nitrogen (Phase I)		Report mg/l		WLA
Ammonia Nitrogen (Phase II)		2 mg/l			WLA
Minimum DO				6 mg/l			WLA
TSS					90 mg/l 		Technology
Chlorine, Total Residual		< 1.0 mg/l		WLA
pH					6.0 – 9.0 SU		Admin Code
Total Nitrogen (Phase I)		Report lbs/day		WLA
Total Nitrogen (Phase II)		15.4 lbs/day		WLA
Total Phosphorus (Phase I)		Report lbs/day		WLA
Total Phosphorus (Phase II)		6.9 lbs/day		WLA

Upon issuance of this permit, the permittee shall achieve compliance with the effluent limitations specified 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 five (5) years after the issuance of the permit, whichever comes first, the permittee shall achieve compliance with the effluent limitations specified for the parameters noted as Phase II; Phase I limitations shall not apply at this time. The permittee shall notify our office orally at least 48 hours prior to start-up and in writing no later than 5 days after start-up.