DRAFT PERMIT RATIONALE FOR REISSUANCE
Williams Equipment and Supply
Lee County
Shannon, Mississippi
Water NPDES No. MS0060861
August 9, 2022

I.	FACILITY INFORMATION

Facility Name:		Williams Equipment and Supply
Facility Address:	122 County Road 713 
	Shannon, MS  38868    
Shannon, 
Permit No.:		MS0060861
SIC:			5082
Permit Writer:		Rusty Parrish
EPD Branch:		Water II Branch

II.	NATURE OF BUSINESS

Williams Equipment and Supply sales and rents compact construction equipment. 

III.	EFFLUENT AND RECEIVING STREAM FLOW DATA

Williams Equipment and Supply discharges 0.001 MGD of equipment washdown through an existing outfall into an unnamed tributary of Coonewah Creek thence into Town Creek. 

IV.	TYPE OF WASTEWATER TREATMENT

Equipment washdown is treated by an oil/water separator and sedimentation basin.

V.	303(d) and TOTAL MAXIMUM DAILY LOADS (TMDLs) ISSUES

Coonewah Creek is on the Mississippi 2022 List of Impaired Water Bodies list for biological impairment. The following TMDLs are applicable:

•	Fecal Coliform – Town Creek – Chickasaw, Itawamba, Lee, Monroe, Pontotoc, Prentiss, and Union Counties – June 2002 – ID: 802062101
•	Nutrient – Town Creek – Union, Pontotoc, and Lee Counties – October 2009
•	Sediment – Town Creek – Tombigbee River Basin – January 2007 – ID: 807012602
•	DDT and Toxaphene – Big Black and Tombigbee River Basins – November 2005 – ID: 105111401

VI.	EPA APPLICABLE CATEGORICAL GUIDELINES

None.

VII.	DATA FROM MISSISSIPPI SMALL DOMESTIC NPDES APPLICATION FORM

Application testing waiver was requested and approved.

VIII.	PROPOSED FINAL LIMITATIONS 

Outfall 001
Parameter	Current Permit Limit (CPL)	Present Permit Limit (PPL)	Basis	
	Average	Maximum	Average	Maximum		
Flow	Report	Report	Report	Report	Average Design	
pH	6.0 SU (min)	9.0 SU	6.0 SU (min)	9.0 SU	MSWQS	
Oil and Grease	10 mg/L	15 mg/L	10 mg/L	15 mg/L	1/	
Total Suspended Solids 	30 mg/L	45 mg/L	30 mg/L	45 mg/L	1/	
		MSWQS = Mississippi Water Quality Standards

1/Proposed permit limits for Oil and Grease and Total Suspended Solids are comparable to limits placed in permits held by existing similar commercial car wash facilities in the State of Mississippi.  

Effluent Limits have been developed such that the waste treatment system should protect water quality.  However, this permit is subject to modification if future evidence, monitoring results, or nuisance conditions indicate a higher degree of treatment is required to maintain water quality in the receiving stream.