PERMIT RATIONALE FOR REISSUANCE
MDOT, Interstate 10 Welcome Center
Jackson County
Moss Point, Mississippi
Water NPDES No. MS0037966
April 4, 2017

I.	CLASSIFICATION – Domestic NPDES

II.	DESCRIPTION OF WASTEWATER – Minor Domestic

III.	DESCRIPTION OF WASTEWATER TREATMENT – Domestic wastewater is collected and treated via an activated sludge system.  

IV.	RECEIVING WATERS – An unnamed creek thence into the Escatawpa River. The Escatawpa River is included in a completed TMDL for mercury. It does not appear on the current 303(d) List of Impaired Waterbodies. This waterbody is in the Pascagoula River drainage basin.  The Escatawpa River is classified as Fish and Wildlife.  One discharge to surface waters is described within the application with no increase in flow proposed. The discharge from this facility should not further impair water quality.

V.	APPLICABLE GUIDELINES – State of Mississippi Wastewater Regulations (WPC-1),  State of Mississippi Water Quality Criteria, Commercial Facility Guidelines

VI.	SUMMARY OF DISCHARGE LIMITATIONS – 

Parameter		Value					Basis
Flow			0.07 MGD				Design
BOD			30 mg/l				Previous Permit
TSS			30 mg/l				Domestic Guidelines
E Coli			126 Col./100mL			Domestic Guidelines
Effluent pH		6.0 to 9.0 S.U.				MS WQS
Chlorine		0.1 to 1.0 mg/l				Domestic Guidelines
	
The minimum and maximum values for Influent ph, Dissolved Oxygen in aeration unit, and 30-Minute Sludge Settleability in aeration unit must be reported

E. Coli will now be the bacterial indicator used for all freshwaters in MS designated as Recreation, Fish and Wildlife Support, and /or Public Water supply (replacing the use of fecal coliform).