PERMIT RATIONALE FOR REISSUANCE
Tunica County Utility District, Grand Casino
Tunica County
Robinsonville, Mississippi
Water NPDES No. MS0047635
October 2023

I.	FACILITY INFORMATION

Facility Name:  Tunica County Utility District, Grand Casino
Facility Address:  Grand Casino Parkway 
 Robinsonville, MS 38664    
Robinsonville, 
Permit No.:  MS0047635
SIC:  4952
Permit Writer:  Christiana Boren
EPD Branch:  Municipal and Private Facilities

II.	CLASSIFICATION – NPDES Minor Municipal

III.	DESCRIPTION OF WASTEWATER – Municipal Wastewater

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

V.	RECEVING WATERS – Mississippi River. The receiving waters are located within the Mississippi River drainage basin and are classified as Fish & Wildlife. At the point of discharge, the receiving water is not listed on the current State of Mississippi 303(d) List of Impaired Waterbodies, nor is the facility listed in a completed Total Maximum Daily Load (TMDL)

At the point of discharge the 7Q10 for the receiving stream is 100000 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, 0.67 MGD or 1.04 cfs
		 Qr = Receiving stream 7Q10, 100000 cfs.

IWC = {(1.04 cfs)/(1.04 cfs + 100000 cfs)}*100 = 0.001 %

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

VII.	CHANGES FROM PREVIOUS PERMIT – None. 

VIII.	SUMMARY OF DISCHARGE LIMITATIONS – 
Parameter			Flow				Basis
Flow				0.67 MGD			Design
BOD5				30 mg/l 			Technology
TSS				30 mg/l			Technology
Ammonia-Nitrogen		Report	mg/l			WLA
E. coli				126 Col./100 ml		Admin Code
Chlorine, Total Residual	0.1 - 1.0 mg/l			Admin Code
pH				6.0 – 9.0 SU			Admin Code
Total Nitrogen			Report lbs/day			WLA
Total Phosphorus		Report lbs/day			WLA

The minimum and maximum values for Dissolved Oxygen and Sludge Settleability in the aeration unit and influent pH must be reported.