PERMIT RATIONALE FOR REISSUANCE
MDOT, Interstate 55 South, Rest Area, Carroll
Carroll County
Vaiden, Mississippi
Water NPDES No. MS0036510
January 2018

I.	CLASSIFICATION – NPDES Commercial

II.	DESCRIPTION OF WASTEWATER – Domestic

III.	DESCRIPTION OF WASTEWATER TREATMENT – Domestic wastewater is collected and treated via an activated sludge system. Only one discharge to surface waters is described in the application with no increase in treated effluent flow proposed. 

IV.	RECEIVING WATERS – An unnamed stream thence to Peachahala Creek. The receiving waters are located in the Big Black River 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 in a completed Total Maximum Daily Load (TMDL). 

V.	APPLICABLE GUIDELINES – 11 Mississippi Admin Code pt. 6, Commercial Facility Guidelines (Technology)

VI.	SUMMARY OF DISCHARGE LIMITATIONS – 

Parameter		Value				Basis
Flow			0.015 MGD			Design
BOD			30 mg/l			Technology
TSS			30 mg/l			Technology
E. coli			126 Col./100mL		Admin Code
pH (effluent)		6.0 - 9.0 S.U.			Admin Code
Chlorine		0.1 - 1.0 mg/l			Admin Code
	
The minimum and maximum values for Influent pH, Dissolved Oxygen in aeration unit, and 30-Minute Sludge Settleability in aeration unit must be reported.

VII.	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.