PERMIT RATIONALE FOR REISSUANCE
MDOT, Interstate 20 Truck Scales, Warren
Warren County
Vicksburg, Mississippi
Water NPDES No. MS0044300
October 10, 2025

I.	CLASSIFICATION – Commercial NPDES

II.	DESCRIPTION OF WASTEWATER – Domestic Wastewater

III.	DESCRIPTION OF WASTEWATER TREATMENT – Domestic wastewater is collected and treated biologically by means of an aerobic treatment unit (ATU). The facility consists of two separate truck scales, each having its own ATU for treatment of its domestic wastewater, and its own separate outfall to the receiving stream. The treatment capacity for each system is 0.0015 MGD. No increase in treated effluent is proposed within the application. 

IV.	RECEIVING WATERS – Outfall 001 and 002 both discharge into an unnamed tributary of Muddy Creek. At the point of discharge Muddy Creek does appear on the current State of Mississippi 303(d) List of Impaired Waterbodies for Biological Impairment. The facility does not appear in a completed TMDL. Two separate discharges are described within the application. The discharges are an existing source with no proposed increase in treated effluent; therefore, the facility will not further impair water quality. The receiving streams are located within the Big Black River and are classified as Fish & Wildlife. 

V.	APPLICABLE GUIDELINES – 11 Mississippi Admin Code Pt. 6, Domestic Guidlines

VI.	SUMMARY OF DISCHARGE LIMITATIONS – 
Outfall 001
Parameter		Value					Basis
Flow			0.0015 MGD		Design
BOD5			30 mg/l (Monthly Average)		Domestic Guidelines
TSS			30 mg/l (Monthly Average)		Technology
Fecal Coliform	200 Col./100ml		MSWQS
Chlorine, T.R.		0.1 – 1.0 mg/l		Domestic Guidelines
pH			6.0 – 9.0 SU		MSWQS

Parameter		Value					Basis
Flow			0.0015 MGD		Design
BOD5			30 mg/l (Monthly Average)		Domestic Guidelines
TSS			30 mg/l (Monthly Average)		Technology
Fecal Coliform	200 Col./100ml		MSWQS
Chlorine, T.R.		0.1 – 1.0 mg/l		Domestic Guidelines
pH			6.0 – 9.0 SU		MSWQS